11 files changed, 1059 insertions, 111 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 2ace866ee..a56e526a6 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -310,6 +310,8 @@ add_library(core STATIC
     hle/service/mig/mig.h
     hle/service/mii/mii.cpp
     hle/service/mii/mii.h
+    hle/service/mii/mii_manager.cpp
+    hle/service/mii/mii_manager.h
     hle/service/mm/mm_u.cpp
     hle/service/mm/mm_u.h
     hle/service/ncm/ncm.cpp
diff --git a/src/core/frontend/applets/profile_select.cpp b/src/core/frontend/applets/profile_select.cpp
index fbf5f2a9e..4df3574d2 100644
--- a/src/core/frontend/applets/profile_select.cpp
+++ b/src/core/frontend/applets/profile_select.cpp
@@ -3,6 +3,7 @@
 // Refer to the license.txt file included.
 
 #include "core/frontend/applets/profile_select.h"
+#include "core/hle/service/acc/profile_manager.h"
 #include "core/settings.h"
 
 namespace Core::Frontend {
@@ -10,9 +11,9 @@ namespace Core::Frontend {
 ProfileSelectApplet::~ProfileSelectApplet() = default;
 
 void DefaultProfileSelectApplet::SelectProfile(
-    std::function<void(std::optional<Service::Account::UUID>)> callback) const {
+    std::function<void(std::optional<Common::UUID>)> callback) const {
     Service::Account::ProfileManager manager;
-    callback(manager.GetUser(Settings::values.current_user).value_or(Service::Account::UUID{}));
+    callback(manager.GetUser(Settings::values.current_user).value_or(Common::UUID{}));
     LOG_INFO(Service_ACC, "called, selecting current user instead of prompting...");
 }
 
diff --git a/src/core/frontend/applets/profile_select.h b/src/core/frontend/applets/profile_select.h
index fc8f7ae94..3506b9885 100644
--- a/src/core/frontend/applets/profile_select.h
+++ b/src/core/frontend/applets/profile_select.h
@@ -6,7 +6,7 @@
 
 #include <functional>
 #include <optional>
-#include "core/hle/service/acc/profile_manager.h"
+#include "common/uuid.h"
 
 namespace Core::Frontend {
 
@@ -14,14 +14,12 @@ class ProfileSelectApplet {
 public:
     virtual ~ProfileSelectApplet();
 
-    virtual void SelectProfile(
-        std::function<void(std::optional<Service::Account::UUID>)> callback) const = 0;
+    virtual void SelectProfile(std::function<void(std::optional<Common::UUID>)> callback) const = 0;
 };
 
 class DefaultProfileSelectApplet final : public ProfileSelectApplet {
 public:
-    void SelectProfile(
-        std::function<void(std::optional<Service::Account::UUID>)> callback) const override;
+    void SelectProfile(std::function<void(std::optional<Common::UUID>)> callback) const override;
 };
 
 } // namespace Core::Frontend
diff --git a/src/core/hle/service/acc/acc.cpp b/src/core/hle/service/acc/acc.cpp
index ba7d7acbd..86bf53d08 100644
--- a/src/core/hle/service/acc/acc.cpp
+++ b/src/core/hle/service/acc/acc.cpp
@@ -34,7 +34,7 @@ constexpr std::array<u8, backup_jpeg_size> backup_jpeg{{
     0x01, 0x01, 0x00, 0x00, 0x3f, 0x00, 0xd2, 0xcf, 0x20, 0xff, 0xd9,
 }};
 
-static std::string GetImagePath(UUID uuid) {
+static std::string GetImagePath(Common::UUID uuid) {
     return FileUtil::GetUserPath(FileUtil::UserPath::NANDDir) +
            "/system/save/8000000000000010/su/avators/" + uuid.FormatSwitch() + ".jpg";
 }
@@ -46,7 +46,7 @@ static constexpr u32 SanitizeJPEGSize(std::size_t size) {
 
 class IProfile final : public ServiceFramework<IProfile> {
 public:
-    explicit IProfile(UUID user_id, ProfileManager& profile_manager)
+    explicit IProfile(Common::UUID user_id, ProfileManager& profile_manager)
         : ServiceFramework("IProfile"), profile_manager(profile_manager), user_id(user_id) {
         static const FunctionInfo functions[] = {
             {0, &IProfile::Get, "Get"},
@@ -131,7 +131,7 @@ private:
     }
 
     const ProfileManager& profile_manager;
-    UUID user_id; ///< The user id this profile refers to.
+    Common::UUID user_id; ///< The user id this profile refers to.
 };
 
 class IManagerForApplication final : public ServiceFramework<IManagerForApplication> {
@@ -179,7 +179,7 @@ void Module::Interface::GetUserCount(Kernel::HLERequestContext& ctx) {
 
 void Module::Interface::GetUserExistence(Kernel::HLERequestContext& ctx) {
     IPC::RequestParser rp{ctx};
-    UUID user_id = rp.PopRaw<UUID>();
+    Common::UUID user_id = rp.PopRaw<Common::UUID>();
     LOG_INFO(Service_ACC, "called user_id={}", user_id.Format());
 
     IPC::ResponseBuilder rb{ctx, 3};
@@ -205,12 +205,12 @@ void Module::Interface::GetLastOpenedUser(Kernel::HLERequestContext& ctx) {
     LOG_INFO(Service_ACC, "called");
     IPC::ResponseBuilder rb{ctx, 6};
     rb.Push(RESULT_SUCCESS);
-    rb.PushRaw<UUID>(profile_manager->GetLastOpenedUser());
+    rb.PushRaw<Common::UUID>(profile_manager->GetLastOpenedUser());
 }
 
 void Module::Interface::GetProfile(Kernel::HLERequestContext& ctx) {
     IPC::RequestParser rp{ctx};
-    UUID user_id = rp.PopRaw<UUID>();
+    Common::UUID user_id = rp.PopRaw<Common::UUID>();
     LOG_DEBUG(Service_ACC, "called user_id={}", user_id.Format());
 
     IPC::ResponseBuilder rb{ctx, 2, 0, 1};
@@ -245,15 +245,15 @@ void Module::Interface::TrySelectUserWithoutInteraction(Kernel::HLERequestContex
     IPC::ResponseBuilder rb{ctx, 6};
     if (profile_manager->GetUserCount() != 1) {
         rb.Push(RESULT_SUCCESS);
-        rb.PushRaw<u128>(INVALID_UUID);
+        rb.PushRaw<u128>(Common::INVALID_UUID);
         return;
     }
 
     const auto user_list = profile_manager->GetAllUsers();
     if (std::all_of(user_list.begin(), user_list.end(),
-                    [](const auto& user) { return user.uuid == INVALID_UUID; })) {
+                    [](const auto& user) { return user.uuid == Common::INVALID_UUID; })) {
         rb.Push(ResultCode(-1)); // TODO(ogniK): Find the correct error code
-        rb.PushRaw<u128>(INVALID_UUID);
+        rb.PushRaw<u128>(Common::INVALID_UUID);
         return;
     }
 
diff --git a/src/core/hle/service/acc/profile_manager.cpp b/src/core/hle/service/acc/profile_manager.cpp
index 1316d0b07..49aa5908b 100644
--- a/src/core/hle/service/acc/profile_manager.cpp
+++ b/src/core/hle/service/acc/profile_manager.cpp
@@ -13,6 +13,8 @@
 
 namespace Service::Account {
 
+using Common::UUID;
+
 struct UserRaw {
     UUID uuid;
     UUID uuid2;
@@ -35,26 +37,6 @@ constexpr ResultCode ERROR_ARGUMENT_IS_NULL(ErrorModule::Account, 20);
 
 constexpr char ACC_SAVE_AVATORS_BASE_PATH[] = "/system/save/8000000000000010/su/avators/";
 
-UUID UUID::Generate() {
-    std::random_device device;
-    std::mt19937 gen(device());
-    std::uniform_int_distribution<u64> distribution(1, std::numeric_limits<u64>::max());
-    return UUID{distribution(gen), distribution(gen)};
-}
-
-std::string UUID::Format() const {
-    return fmt::format("0x{:016X}{:016X}", uuid[1], uuid[0]);
-}
-
-std::string UUID::FormatSwitch() const {
-    std::array<u8, 16> s{};
-    std::memcpy(s.data(), uuid.data(), sizeof(u128));
-    return fmt::format("{:02x}{:02x}{:02x}{:02x}-{:02x}{:02x}-{:02x}{:02x}-{:02x}{:02x}-{:02x}{"
-                       ":02x}{:02x}{:02x}{:02x}{:02x}",
-                       s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7], s[8], s[9], s[10], s[11],
-                       s[12], s[13], s[14], s[15]);
-}
-
 ProfileManager::ProfileManager() {
     ParseUserSaveFile();
 
@@ -217,7 +199,7 @@ bool ProfileManager::UserExists(UUID uuid) const {
 bool ProfileManager::UserExistsIndex(std::size_t index) const {
     if (index >= MAX_USERS)
         return false;
-    return profiles[index].user_uuid.uuid != INVALID_UUID;
+    return profiles[index].user_uuid.uuid != Common::INVALID_UUID;
 }
 
 /// Opens a specific user
@@ -311,7 +293,7 @@ bool ProfileManager::RemoveUser(UUID uuid) {
 
 bool ProfileManager::SetProfileBase(UUID uuid, const ProfileBase& profile_new) {
     const auto index = GetUserIndex(uuid);
-    if (!index || profile_new.user_uuid == UUID(INVALID_UUID)) {
+    if (!index || profile_new.user_uuid == UUID(Common::INVALID_UUID)) {
         return false;
     }
 
@@ -342,7 +324,7 @@ void ProfileManager::ParseUserSaveFile() {
     }
 
     for (const auto& user : data.users) {
-        if (user.uuid == UUID(INVALID_UUID)) {
+        if (user.uuid == UUID(Common::INVALID_UUID)) {
             continue;
         }
 
diff --git a/src/core/hle/service/acc/profile_manager.h b/src/core/hle/service/acc/profile_manager.h
index c4ce2e0b3..fd7abb541 100644
--- a/src/core/hle/service/acc/profile_manager.h
+++ b/src/core/hle/service/acc/profile_manager.h
@@ -9,47 +9,15 @@
 
 #include "common/common_types.h"
 #include "common/swap.h"
+#include "common/uuid.h"
 #include "core/hle/result.h"
 
 namespace Service::Account {
 constexpr std::size_t MAX_USERS = 8;
-constexpr u128 INVALID_UUID{{0, 0}};
-
-struct UUID {
-    // UUIDs which are 0 are considered invalid!
-    u128 uuid = INVALID_UUID;
-    UUID() = default;
-    explicit UUID(const u128& id) : uuid{id} {}
-    explicit UUID(const u64 lo, const u64 hi) : uuid{{lo, hi}} {}
-
-    explicit operator bool() const {
-        return uuid != INVALID_UUID;
-    }
-
-    bool operator==(const UUID& rhs) const {
-        return uuid == rhs.uuid;
-    }
-
-    bool operator!=(const UUID& rhs) const {
-        return !operator==(rhs);
-    }
-
-    // TODO(ogniK): Properly generate uuids based on RFC-4122
-    static UUID Generate();
-
-    // Set the UUID to {0,0} to be considered an invalid user
-    void Invalidate() {
-        uuid = INVALID_UUID;
-    }
-
-    std::string Format() const;
-    std::string FormatSwitch() const;
-};
-static_assert(sizeof(UUID) == 16, "UUID is an invalid size!");
 
 constexpr std::size_t profile_username_size = 32;
 using ProfileUsername = std::array<u8, profile_username_size>;
-using UserIDArray = std::array<UUID, MAX_USERS>;
+using UserIDArray = std::array<Common::UUID, MAX_USERS>;
 
 /// Contains extra data related to a user.
 /// TODO: RE this structure
@@ -66,7 +34,7 @@ static_assert(sizeof(ProfileData) == 0x80, "ProfileData structure has incorrect
 /// This holds general information about a users profile. This is where we store all the information
 /// based on a specific user
 struct ProfileInfo {
-    UUID user_uuid;
+    Common::UUID user_uuid;
     ProfileUsername username;
     u64 creation_time;
     ProfileData data; // TODO(ognik): Work out what this is
@@ -74,7 +42,7 @@ struct ProfileInfo {
 };
 
 struct ProfileBase {
-    UUID user_uuid;
+    Common::UUID user_uuid;
     u64_le timestamp;
     ProfileUsername username;
 
@@ -96,33 +64,33 @@ public:
     ~ProfileManager();
 
     ResultCode AddUser(const ProfileInfo& user);
-    ResultCode CreateNewUser(UUID uuid, const ProfileUsername& username);
-    ResultCode CreateNewUser(UUID uuid, const std::string& username);
-    std::optional<UUID> GetUser(std::size_t index) const;
-    std::optional<std::size_t> GetUserIndex(const UUID& uuid) const;
+    ResultCode CreateNewUser(Common::UUID uuid, const ProfileUsername& username);
+    ResultCode CreateNewUser(Common::UUID uuid, const std::string& username);
+    std::optional<Common::UUID> GetUser(std::size_t index) const;
+    std::optional<std::size_t> GetUserIndex(const Common::UUID& uuid) const;
     std::optional<std::size_t> GetUserIndex(const ProfileInfo& user) const;
     bool GetProfileBase(std::optional<std::size_t> index, ProfileBase& profile) const;
-    bool GetProfileBase(UUID uuid, ProfileBase& profile) const;
+    bool GetProfileBase(Common::UUID uuid, ProfileBase& profile) const;
     bool GetProfileBase(const ProfileInfo& user, ProfileBase& profile) const;
     bool GetProfileBaseAndData(std::optional<std::size_t> index, ProfileBase& profile,
                                ProfileData& data) const;
-    bool GetProfileBaseAndData(UUID uuid, ProfileBase& profile, ProfileData& data) const;
+    bool GetProfileBaseAndData(Common::UUID uuid, ProfileBase& profile, ProfileData& data) const;
     bool GetProfileBaseAndData(const ProfileInfo& user, ProfileBase& profile,
                                ProfileData& data) const;
     std::size_t GetUserCount() const;
     std::size_t GetOpenUserCount() const;
-    bool UserExists(UUID uuid) const;
+    bool UserExists(Common::UUID uuid) const;
     bool UserExistsIndex(std::size_t index) const;
-    void OpenUser(UUID uuid);
-    void CloseUser(UUID uuid);
+    void OpenUser(Common::UUID uuid);
+    void CloseUser(Common::UUID uuid);
     UserIDArray GetOpenUsers() const;
     UserIDArray GetAllUsers() const;
-    UUID GetLastOpenedUser() const;
+    Common::UUID GetLastOpenedUser() const;
 
     bool CanSystemRegisterUser() const;
 
-    bool RemoveUser(UUID uuid);
-    bool SetProfileBase(UUID uuid, const ProfileBase& profile_new);
+    bool RemoveUser(Common::UUID uuid);
+    bool SetProfileBase(Common::UUID uuid, const ProfileBase& profile_new);
 
 private:
     void ParseUserSaveFile();
@@ -132,7 +100,7 @@ private:
 
     std::array<ProfileInfo, MAX_USERS> profiles{};
     std::size_t user_count = 0;
-    UUID last_opened_user{INVALID_UUID};
+    Common::UUID last_opened_user{Common::INVALID_UUID};
 };
 
 }; // namespace Service::Account
diff --git a/src/core/hle/service/am/applets/profile_select.cpp b/src/core/hle/service/am/applets/profile_select.cpp
index d113bd2eb..57b5419e8 100644
--- a/src/core/hle/service/am/applets/profile_select.cpp
+++ b/src/core/hle/service/am/applets/profile_select.cpp
@@ -53,19 +53,19 @@ void ProfileSelect::Execute() {
         return;
     }
 
-    frontend.SelectProfile([this](std::optional<Account::UUID> uuid) { SelectionComplete(uuid); });
+    frontend.SelectProfile([this](std::optional<Common::UUID> uuid) { SelectionComplete(uuid); });
 }
 
-void ProfileSelect::SelectionComplete(std::optional<Account::UUID> uuid) {
+void ProfileSelect::SelectionComplete(std::optional<Common::UUID> uuid) {
     UserSelectionOutput output{};
 
-    if (uuid.has_value() && uuid->uuid != Account::INVALID_UUID) {
+    if (uuid.has_value() && uuid->uuid != Common::INVALID_UUID) {
         output.result = 0;
         output.uuid_selected = uuid->uuid;
     } else {
         status = ERR_USER_CANCELLED_SELECTION;
         output.result = ERR_USER_CANCELLED_SELECTION.raw;
-        output.uuid_selected = Account::INVALID_UUID;
+        output.uuid_selected = Common::INVALID_UUID;
     }
 
     final_data = std::vector<u8>(sizeof(UserSelectionOutput));
diff --git a/src/core/hle/service/am/applets/profile_select.h b/src/core/hle/service/am/applets/profile_select.h
index a2ac6cf50..563cd744a 100644
--- a/src/core/hle/service/am/applets/profile_select.h
+++ b/src/core/hle/service/am/applets/profile_select.h
@@ -7,7 +7,8 @@
 #include <vector>
 
 #include "common/common_funcs.h"
-#include "core/hle/service/acc/profile_manager.h"
+#include "common/uuid.h"
+#include "core/hle/result.h"
 #include "core/hle/service/am/applets/applets.h"
 
 namespace Service::AM::Applets {
@@ -38,7 +39,7 @@ public:
     void ExecuteInteractive() override;
     void Execute() override;
 
-    void SelectionComplete(std::optional<Account::UUID> uuid);
+    void SelectionComplete(std::optional<Common::UUID> uuid);
 
 private:
     const Core::Frontend::ProfileSelectApplet& frontend;
diff --git a/src/core/hle/service/mii/mii.cpp b/src/core/hle/service/mii/mii.cpp
index a6197124a..ce84e25ed 100644
--- a/src/core/hle/service/mii/mii.cpp
+++ b/src/core/hle/service/mii/mii.cpp
@@ -4,42 +4,50 @@
 
 #include <memory>
 
+#include <fmt/ostream.h>
+
 #include "common/logging/log.h"
+#include "common/string_util.h"
 #include "core/hle/ipc_helpers.h"
 #include "core/hle/kernel/hle_ipc.h"
 #include "core/hle/service/mii/mii.h"
+#include "core/hle/service/mii/mii_manager.h"
 #include "core/hle/service/service.h"
 #include "core/hle/service/sm/sm.h"
 
 namespace Service::Mii {
 
+constexpr ResultCode ERROR_INVALID_ARGUMENT{ErrorModule::Mii, 1};
+constexpr ResultCode ERROR_CANNOT_FIND_ENTRY{ErrorModule::Mii, 4};
+constexpr ResultCode ERROR_NOT_IN_TEST_MODE{ErrorModule::Mii, 99};
+
 class IDatabaseService final : public ServiceFramework<IDatabaseService> {
 public:
     explicit IDatabaseService() : ServiceFramework{"IDatabaseService"} {
         // clang-format off
         static const FunctionInfo functions[] = {
-            {0, nullptr, "IsUpdated"},
-            {1, nullptr, "IsFullDatabase"},
-            {2, nullptr, "GetCount"},
-            {3, nullptr, "Get"},
-            {4, nullptr, "Get1"},
+            {0, &IDatabaseService::IsUpdated, "IsUpdated"},
+            {1, &IDatabaseService::IsFullDatabase, "IsFullDatabase"},
+            {2, &IDatabaseService::GetCount, "GetCount"},
+            {3, &IDatabaseService::Get, "Get"},
+            {4, &IDatabaseService::Get1, "Get1"},
             {5, nullptr, "UpdateLatest"},
-            {6, nullptr, "BuildRandom"},
-            {7, nullptr, "BuildDefault"},
-            {8, nullptr, "Get2"},
-            {9, nullptr, "Get3"},
+            {6, &IDatabaseService::BuildRandom, "BuildRandom"},
+            {7, &IDatabaseService::BuildDefault, "BuildDefault"},
+            {8, &IDatabaseService::Get2, "Get2"},
+            {9, &IDatabaseService::Get3, "Get3"},
             {10, nullptr, "UpdateLatest1"},
-            {11, nullptr, "FindIndex"},
-            {12, nullptr, "Move"},
-            {13, nullptr, "AddOrReplace"},
-            {14, nullptr, "Delete"},
-            {15, nullptr, "DestroyFile"},
-            {16, nullptr, "DeleteFile"},
-            {17, nullptr, "Format"},
+            {11, &IDatabaseService::FindIndex, "FindIndex"},
+            {12, &IDatabaseService::Move, "Move"},
+            {13, &IDatabaseService::AddOrReplace, "AddOrReplace"},
+            {14, &IDatabaseService::Delete, "Delete"},
+            {15, &IDatabaseService::DestroyFile, "DestroyFile"},
+            {16, &IDatabaseService::DeleteFile, "DeleteFile"},
+            {17, &IDatabaseService::Format, "Format"},
             {18, nullptr, "Import"},
             {19, nullptr, "Export"},
             {20, nullptr, "IsBrokenDatabaseWithClearFlag"},
-            {21, nullptr, "GetIndex"},
+            {21, &IDatabaseService::GetIndex, "GetIndex"},
             {22, nullptr, "SetInterfaceVersion"},
             {23, nullptr, "Convert"},
         };
@@ -47,6 +55,305 @@ public:
 
         RegisterHandlers(functions);
     }
+
+private:
+    template <typename OutType>
+    std::vector<u8> SerializeArray(OutType (MiiManager::*getter)(u32) const, u32 offset,
+                                   u32 requested_size, u32& read_size) {
+        read_size = std::min(requested_size, db.Size() - offset);
+
+        std::vector<u8> out(read_size * sizeof(OutType));
+
+        for (u32 i = 0; i < read_size; ++i) {
+            const auto obj = (db.*getter)(offset + i);
+            std::memcpy(out.data() + i * sizeof(OutType), &obj, sizeof(OutType));
+        }
+
+        return out;
+    }
+
+    void IsUpdated(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto source{rp.PopRaw<Source>()};
+
+        LOG_DEBUG(Service_Mii, "called with source={}", source);
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push(db.CheckUpdatedFlag());
+        db.ResetUpdatedFlag();
+    }
+
+    void IsFullDatabase(Kernel::HLERequestContext& ctx) {
+        LOG_DEBUG(Service_Mii, "called");
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push(db.Full());
+    }
+
+    void GetCount(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto source{rp.PopRaw<Source>()};
+
+        LOG_DEBUG(Service_Mii, "called with source={}", source);
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push<u32>(db.Size());
+    }
+
+    // Gets Miis from database at offset and index in format MiiInfoElement
+    void Get(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto size{rp.PopRaw<u32>()};
+        const auto source{rp.PopRaw<Source>()};
+
+        LOG_DEBUG(Service_Mii, "called with size={:08X}, offset={:08X}, source={}", size,
+                  offsets[0], source);
+
+        u32 read_size{};
+        ctx.WriteBuffer(SerializeArray(&MiiManager::GetInfoElement, offsets[0], size, read_size));
+        offsets[0] += read_size;
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push<u32>(read_size);
+    }
+
+    // Gets Miis from database at offset and index in format MiiInfo
+    void Get1(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto size{rp.PopRaw<u32>()};
+        const auto source{rp.PopRaw<Source>()};
+
+        LOG_DEBUG(Service_Mii, "called with size={:08X}, offset={:08X}, source={}", size,
+                  offsets[1], source);
+
+        u32 read_size{};
+        ctx.WriteBuffer(SerializeArray(&MiiManager::GetInfo, offsets[1], size, read_size));
+        offsets[1] += read_size;
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push<u32>(read_size);
+    }
+
+    void BuildRandom(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto [unknown1, unknown2, unknown3] = rp.PopRaw<RandomParameters>();
+
+        if (unknown1 > 3) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ERROR_INVALID_ARGUMENT);
+            LOG_ERROR(Service_Mii, "Invalid unknown1 value: {}", unknown1);
+            return;
+        }
+
+        if (unknown2 > 2) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ERROR_INVALID_ARGUMENT);
+            LOG_ERROR(Service_Mii, "Invalid unknown2 value: {}", unknown2);
+            return;
+        }
+
+        if (unknown3 > 3) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ERROR_INVALID_ARGUMENT);
+            LOG_ERROR(Service_Mii, "Invalid unknown3 value: {}", unknown3);
+            return;
+        }
+
+        LOG_DEBUG(Service_Mii, "called with param_1={:08X}, param_2={:08X}, param_3={:08X}",
+                  unknown1, unknown2, unknown3);
+
+        const auto info = db.CreateRandom({unknown1, unknown2, unknown3});
+        IPC::ResponseBuilder rb{ctx, 2 + sizeof(MiiInfo) / sizeof(u32)};
+        rb.Push(RESULT_SUCCESS);
+        rb.PushRaw<MiiInfo>(info);
+    }
+
+    void BuildDefault(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto index{rp.PopRaw<u32>()};
+
+        if (index > 5) {
+            LOG_ERROR(Service_Mii, "invalid argument, index cannot be greater than 5 but is {:08X}",
+                      index);
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ERROR_INVALID_ARGUMENT);
+            return;
+        }
+
+        LOG_DEBUG(Service_Mii, "called with index={:08X}", index);
+
+        const auto info = db.CreateDefault(index);
+        IPC::ResponseBuilder rb{ctx, 2 + sizeof(MiiInfo) / sizeof(u32)};
+        rb.Push(RESULT_SUCCESS);
+        rb.PushRaw<MiiInfo>(info);
+    }
+
+    // Gets Miis from database at offset and index in format MiiStoreDataElement
+    void Get2(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto size{rp.PopRaw<u32>()};
+        const auto source{rp.PopRaw<Source>()};
+
+        LOG_DEBUG(Service_Mii, "called with size={:08X}, offset={:08X}, source={}", size,
+                  offsets[2], source);
+
+        u32 read_size{};
+        ctx.WriteBuffer(
+            SerializeArray(&MiiManager::GetStoreDataElement, offsets[2], size, read_size));
+        offsets[2] += read_size;
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push<u32>(read_size);
+    }
+
+    // Gets Miis from database at offset and index in format MiiStoreData
+    void Get3(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto size{rp.PopRaw<u32>()};
+        const auto source{rp.PopRaw<Source>()};
+
+        LOG_DEBUG(Service_Mii, "called with size={:08X}, offset={:08X}, source={}", size,
+                  offsets[3], source);
+
+        u32 read_size{};
+        ctx.WriteBuffer(SerializeArray(&MiiManager::GetStoreData, offsets[3], size, read_size));
+        offsets[3] += read_size;
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push<u32>(read_size);
+    }
+
+    void FindIndex(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto uuid{rp.PopRaw<Common::UUID>()};
+        const auto unknown{rp.PopRaw<bool>()};
+
+        LOG_DEBUG(Service_Mii, "called with uuid={}, unknown={}", uuid.FormatSwitch(), unknown);
+
+        IPC::ResponseBuilder rb{ctx, 3};
+
+        const auto index = db.IndexOf(uuid);
+        if (index > MAX_MIIS) {
+            // TODO(DarkLordZach): Find a better error code
+            rb.Push(ResultCode(-1));
+            rb.Push(index);
+        } else {
+            rb.Push(RESULT_SUCCESS);
+            rb.Push(index);
+        }
+    }
+
+    void Move(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto uuid{rp.PopRaw<Common::UUID>()};
+        const auto index{rp.PopRaw<s32>()};
+
+        if (index < 0) {
+            LOG_ERROR(Service_Mii, "Index cannot be negative but is {:08X}!", index);
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ERROR_INVALID_ARGUMENT);
+            return;
+        }
+
+        LOG_DEBUG(Service_Mii, "called with uuid={}, index={:08X}", uuid.FormatSwitch(), index);
+
+        const auto success = db.Move(uuid, index);
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        // TODO(DarkLordZach): Find a better error code
+        rb.Push(success ? RESULT_SUCCESS : ResultCode(-1));
+    }
+
+    void AddOrReplace(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto data{rp.PopRaw<MiiStoreData>()};
+
+        LOG_DEBUG(Service_Mii, "called with Mii data uuid={}, name={}", data.uuid.FormatSwitch(),
+                  Common::UTF16ToUTF8(data.Name()));
+
+        const auto success = db.AddOrReplace(data);
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        // TODO(DarkLordZach): Find a better error code
+        rb.Push(success ? RESULT_SUCCESS : ResultCode(-1));
+    }
+
+    void Delete(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto uuid{rp.PopRaw<Common::UUID>()};
+
+        LOG_DEBUG(Service_Mii, "called with uuid={}", uuid.FormatSwitch());
+
+        const auto success = db.Remove(uuid);
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        rb.Push(success ? RESULT_SUCCESS : ERROR_CANNOT_FIND_ENTRY);
+    }
+
+    void DestroyFile(Kernel::HLERequestContext& ctx) {
+        LOG_DEBUG(Service_Mii, "called");
+
+        if (!db.IsTestModeEnabled()) {
+            LOG_ERROR(Service_Mii, "Database is not in test mode -- cannot destory database file.");
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ERROR_NOT_IN_TEST_MODE);
+            return;
+        }
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push(db.DestroyFile());
+    }
+
+    void DeleteFile(Kernel::HLERequestContext& ctx) {
+        LOG_DEBUG(Service_Mii, "called");
+
+        if (!db.IsTestModeEnabled()) {
+            LOG_ERROR(Service_Mii, "Database is not in test mode -- cannot delete database file.");
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ERROR_NOT_IN_TEST_MODE);
+            return;
+        }
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push(db.DeleteFile());
+    }
+
+    void Format(Kernel::HLERequestContext& ctx) {
+        LOG_DEBUG(Service_Mii, "called");
+
+        db.Clear();
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        rb.Push(RESULT_SUCCESS);
+    }
+
+    void GetIndex(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const auto info{rp.PopRaw<MiiInfo>()};
+
+        LOG_DEBUG(Service_Mii, "called with Mii info uuid={}, name={}", info.uuid.FormatSwitch(),
+                  Common::UTF16ToUTF8(info.Name()));
+
+        const auto index = db.IndexOf(info);
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push(index);
+    }
+
+    MiiManager db;
+
+    // Last read offsets of Get functions
+    std::array<u32, 4> offsets{};
 };
 
 class MiiDBModule final : public ServiceFramework<MiiDBModule> {
diff --git a/src/core/hle/service/mii/mii_manager.cpp b/src/core/hle/service/mii/mii_manager.cpp
new file mode 100644
index 000000000..131b01d62
--- /dev/null
+++ b/src/core/hle/service/mii/mii_manager.cpp
@@ -0,0 +1,416 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <cstring>
+#include "common/assert.h"
+#include "common/file_util.h"
+#include "common/logging/log.h"
+#include "common/string_util.h"
+#include "core/hle/service/mii/mii_manager.h"
+
+namespace Service::Mii {
+
+namespace {
+
+constexpr char MII_SAVE_DATABASE_PATH[] = "/system/save/8000000000000030/MiiDatabase.dat";
+constexpr std::array<char16_t, 11> DEFAULT_MII_NAME = {u'y', u'u', u'z', u'u', u'\0'};
+
+// This value was retrieved from HW test
+constexpr MiiStoreData DEFAULT_MII = {
+    {
+        0x21, 0x40, 0x40, 0x01, 0x08, 0x01, 0x13, 0x08, 0x08, 0x02, 0x17, 0x8C, 0x06, 0x01,
+        0x69, 0x6D, 0x8A, 0x6A, 0x82, 0x14, 0x00, 0x00, 0x00, 0x20, 0x64, 0x72, 0x44, 0x44,
+    },
+    {'y', 'u', 'z', 'u', '\0'},
+    Common::UUID{1, 0},
+    0,
+    0,
+};
+
+// Default values taken from multiple real databases
+const MiiDatabase DEFAULT_MII_DATABASE{Common::MakeMagic('N', 'F', 'D', 'B'), {}, {1}, 0, 0};
+
+constexpr std::array<const char*, 4> SOURCE_NAMES{
+    "Database",
+    "Default",
+    "Account",
+    "Friend",
+};
+
+template <typename T, std::size_t SourceArraySize, std::size_t DestArraySize>
+std::array<T, DestArraySize> ResizeArray(const std::array<T, SourceArraySize>& in) {
+    std::array<T, DestArraySize> out{};
+    std::memcpy(out.data(), in.data(), sizeof(T) * std::min(SourceArraySize, DestArraySize));
+    return out;
+}
+
+MiiInfo ConvertStoreDataToInfo(const MiiStoreData& data) {
+    MiiStoreBitFields bf{};
+    std::memcpy(&bf, data.data.data(), sizeof(MiiStoreBitFields));
+    return {
+        data.uuid,
+        ResizeArray<char16_t, 10, 11>(data.name),
+        static_cast<u8>(bf.font_region.Value()),
+        static_cast<u8>(bf.favorite_color.Value()),
+        static_cast<u8>(bf.gender.Value()),
+        static_cast<u8>(bf.height.Value()),
+        static_cast<u8>(bf.weight.Value()),
+        static_cast<u8>(bf.mii_type.Value()),
+        static_cast<u8>(bf.mii_region.Value()),
+        static_cast<u8>(bf.face_type.Value()),
+        static_cast<u8>(bf.face_color.Value()),
+        static_cast<u8>(bf.face_wrinkle.Value()),
+        static_cast<u8>(bf.face_makeup.Value()),
+        static_cast<u8>(bf.hair_type.Value()),
+        static_cast<u8>(bf.hair_color.Value()),
+        static_cast<bool>(bf.hair_flip.Value()),
+        static_cast<u8>(bf.eye_type.Value()),
+        static_cast<u8>(bf.eye_color.Value()),
+        static_cast<u8>(bf.eye_scale.Value()),
+        static_cast<u8>(bf.eye_aspect.Value()),
+        static_cast<u8>(bf.eye_rotate.Value()),
+        static_cast<u8>(bf.eye_x.Value()),
+        static_cast<u8>(bf.eye_y.Value()),
+        static_cast<u8>(bf.eyebrow_type.Value()),
+        static_cast<u8>(bf.eyebrow_color.Value()),
+        static_cast<u8>(bf.eyebrow_scale.Value()),
+        static_cast<u8>(bf.eyebrow_aspect.Value()),
+        static_cast<u8>(bf.eyebrow_rotate.Value()),
+        static_cast<u8>(bf.eyebrow_x.Value()),
+        static_cast<u8>(bf.eyebrow_y.Value()),
+        static_cast<u8>(bf.nose_type.Value()),
+        static_cast<u8>(bf.nose_scale.Value()),
+        static_cast<u8>(bf.nose_y.Value()),
+        static_cast<u8>(bf.mouth_type.Value()),
+        static_cast<u8>(bf.mouth_color.Value()),
+        static_cast<u8>(bf.mouth_scale.Value()),
+        static_cast<u8>(bf.mouth_aspect.Value()),
+        static_cast<u8>(bf.mouth_y.Value()),
+        static_cast<u8>(bf.facial_hair_color.Value()),
+        static_cast<u8>(bf.beard_type.Value()),
+        static_cast<u8>(bf.mustache_type.Value()),
+        static_cast<u8>(bf.mustache_scale.Value()),
+        static_cast<u8>(bf.mustache_y.Value()),
+        static_cast<u8>(bf.glasses_type.Value()),
+        static_cast<u8>(bf.glasses_color.Value()),
+        static_cast<u8>(bf.glasses_scale.Value()),
+        static_cast<u8>(bf.glasses_y.Value()),
+        static_cast<u8>(bf.mole_type.Value()),
+        static_cast<u8>(bf.mole_scale.Value()),
+        static_cast<u8>(bf.mole_x.Value()),
+        static_cast<u8>(bf.mole_y.Value()),
+        0x00,
+    };
+}
+MiiStoreData ConvertInfoToStoreData(const MiiInfo& info) {
+    MiiStoreData out{};
+    out.name = ResizeArray<char16_t, 11, 10>(info.name);
+    out.uuid = info.uuid;
+
+    MiiStoreBitFields bf{};
+
+    bf.hair_type.Assign(info.hair_type);
+    bf.mole_type.Assign(info.mole_type);
+    bf.height.Assign(info.height);
+    bf.hair_flip.Assign(info.hair_flip);
+    bf.weight.Assign(info.weight);
+    bf.hair_color.Assign(info.hair_color);
+
+    bf.gender.Assign(info.gender);
+    bf.eye_color.Assign(info.eye_color);
+    bf.eyebrow_color.Assign(info.eyebrow_color);
+    bf.mouth_color.Assign(info.mouth_color);
+    bf.facial_hair_color.Assign(info.facial_hair_color);
+
+    bf.mii_type.Assign(info.mii_type);
+    bf.glasses_color.Assign(info.glasses_color);
+    bf.font_region.Assign(info.font_region);
+    bf.eye_type.Assign(info.eye_type);
+    bf.mii_region.Assign(info.mii_region);
+    bf.mouth_type.Assign(info.mouth_type);
+    bf.glasses_scale.Assign(info.glasses_scale);
+    bf.eye_y.Assign(info.eye_y);
+
+    bf.mustache_type.Assign(info.mustache_type);
+    bf.eyebrow_type.Assign(info.eyebrow_type);
+    bf.beard_type.Assign(info.beard_type);
+    bf.nose_type.Assign(info.nose_type);
+    bf.mouth_aspect.Assign(info.mouth_aspect_ratio);
+    bf.nose_y.Assign(info.nose_y);
+    bf.eyebrow_aspect.Assign(info.eyebrow_aspect_ratio);
+    bf.mouth_y.Assign(info.mouth_y);
+
+    bf.eye_rotate.Assign(info.eye_rotate);
+    bf.mustache_y.Assign(info.mustache_y);
+    bf.eye_aspect.Assign(info.eye_aspect_ratio);
+    bf.glasses_y.Assign(info.glasses_y);
+    bf.eye_scale.Assign(info.eye_scale);
+    bf.mole_x.Assign(info.mole_x);
+    bf.mole_y.Assign(info.mole_y);
+
+    bf.glasses_type.Assign(info.glasses_type);
+    bf.face_type.Assign(info.face_type);
+    bf.favorite_color.Assign(info.favorite_color);
+    bf.face_wrinkle.Assign(info.face_wrinkle);
+    bf.face_color.Assign(info.face_color);
+    bf.eye_x.Assign(info.eye_x);
+    bf.face_makeup.Assign(info.face_makeup);
+
+    bf.eyebrow_rotate.Assign(info.eyebrow_rotate);
+    bf.eyebrow_scale.Assign(info.eyebrow_scale);
+    bf.eyebrow_y.Assign(info.eyebrow_y);
+    bf.eyebrow_x.Assign(info.eyebrow_x);
+    bf.mouth_scale.Assign(info.mouth_scale);
+    bf.nose_scale.Assign(info.nose_scale);
+    bf.mole_scale.Assign(info.mole_scale);
+    bf.mustache_scale.Assign(info.mustache_scale);
+
+    std::memcpy(out.data.data(), &bf, sizeof(MiiStoreBitFields));
+
+    return out;
+}
+
+} // namespace
+
+std::ostream& operator<<(std::ostream& os, Source source) {
+    os << SOURCE_NAMES.at(static_cast<std::size_t>(source));
+    return os;
+}
+
+std::u16string MiiInfo::Name() const {
+    return Common::UTF16StringFromFixedZeroTerminatedBuffer(name.data(), name.size());
+}
+
+bool operator==(const MiiInfo& lhs, const MiiInfo& rhs) {
+    return std::memcmp(&lhs, &rhs, sizeof(MiiInfo)) == 0;
+}
+
+bool operator!=(const MiiInfo& lhs, const MiiInfo& rhs) {
+    return !operator==(lhs, rhs);
+}
+
+std::u16string MiiStoreData::Name() const {
+    return Common::UTF16StringFromFixedZeroTerminatedBuffer(name.data(), name.size());
+}
+
+MiiManager::MiiManager() = default;
+
+MiiManager::~MiiManager() = default;
+
+MiiInfo MiiManager::CreateRandom(RandomParameters params) {
+    LOG_WARNING(Service_Mii,
+                "(STUBBED) called with params={:08X}{:08X}{:08X}, returning default Mii",
+                params.unknown_1, params.unknown_2, params.unknown_3);
+
+    return ConvertStoreDataToInfo(CreateMiiWithUniqueUUID());
+}
+
+MiiInfo MiiManager::CreateDefault(u32 index) {
+    const auto new_mii = CreateMiiWithUniqueUUID();
+
+    database.miis.at(index) = new_mii;
+
+    EnsureDatabasePartition();
+    return ConvertStoreDataToInfo(new_mii);
+}
+
+bool MiiManager::CheckUpdatedFlag() const {
+    return updated_flag;
+}
+
+void MiiManager::ResetUpdatedFlag() {
+    updated_flag = false;
+}
+
+bool MiiManager::IsTestModeEnabled() const {
+    return is_test_mode_enabled;
+}
+
+bool MiiManager::Empty() const {
+    return Size() == 0;
+}
+
+bool MiiManager::Full() const {
+    return Size() == MAX_MIIS;
+}
+
+void MiiManager::Clear() {
+    updated_flag = true;
+    std::fill(database.miis.begin(), database.miis.end(), MiiStoreData{});
+}
+
+u32 MiiManager::Size() const {
+    return static_cast<u32>(std::count_if(database.miis.begin(), database.miis.end(),
+                                          [](const MiiStoreData& elem) { return elem.uuid; }));
+}
+
+MiiInfo MiiManager::GetInfo(u32 index) const {
+    return ConvertStoreDataToInfo(GetStoreData(index));
+}
+
+MiiInfoElement MiiManager::GetInfoElement(u32 index) const {
+    return {GetInfo(index), Source::Database};
+}
+
+MiiStoreData MiiManager::GetStoreData(u32 index) const {
+    return database.miis.at(index);
+}
+
+MiiStoreDataElement MiiManager::GetStoreDataElement(u32 index) const {
+    return {GetStoreData(index), Source::Database};
+}
+
+bool MiiManager::Remove(Common::UUID uuid) {
+    const auto iter = std::find_if(database.miis.begin(), database.miis.end(),
+                                   [uuid](const MiiStoreData& elem) { return elem.uuid == uuid; });
+
+    if (iter == database.miis.end())
+        return false;
+
+    updated_flag = true;
+    *iter = MiiStoreData{};
+    EnsureDatabasePartition();
+    return true;
+}
+
+u32 MiiManager::IndexOf(Common::UUID uuid) const {
+    const auto iter = std::find_if(database.miis.begin(), database.miis.end(),
+                                   [uuid](const MiiStoreData& elem) { return elem.uuid == uuid; });
+
+    if (iter == database.miis.end())
+        return INVALID_INDEX;
+
+    return static_cast<u32>(std::distance(database.miis.begin(), iter));
+}
+
+u32 MiiManager::IndexOf(const MiiInfo& info) const {
+    const auto iter =
+        std::find_if(database.miis.begin(), database.miis.end(), [&info](const MiiStoreData& elem) {
+            return ConvertStoreDataToInfo(elem) == info;
+        });
+
+    if (iter == database.miis.end())
+        return INVALID_INDEX;
+
+    return static_cast<u32>(std::distance(database.miis.begin(), iter));
+}
+
+bool MiiManager::Move(Common::UUID uuid, u32 new_index) {
+    const auto index = IndexOf(uuid);
+
+    if (index == INVALID_INDEX || new_index >= MAX_MIIS)
+        return false;
+
+    updated_flag = true;
+    const auto moving = database.miis[index];
+    const auto replacing = database.miis[new_index];
+    if (replacing.uuid) {
+        database.miis[index] = replacing;
+        database.miis[new_index] = moving;
+    } else {
+        database.miis[index] = MiiStoreData{};
+        database.miis[new_index] = moving;
+    }
+
+    EnsureDatabasePartition();
+    return true;
+}
+
+bool MiiManager::AddOrReplace(const MiiStoreData& data) {
+    const auto index = IndexOf(data.uuid);
+
+    updated_flag = true;
+    if (index == INVALID_INDEX) {
+        const auto size = Size();
+        if (size == MAX_MIIS)
+            return false;
+        database.miis[size] = data;
+    } else {
+        database.miis[index] = data;
+    }
+
+    return true;
+}
+
+bool MiiManager::DestroyFile() {
+    database = DEFAULT_MII_DATABASE;
+    updated_flag = false;
+    return DeleteFile();
+}
+
+bool MiiManager::DeleteFile() {
+    const auto path = FileUtil::GetUserPath(FileUtil::UserPath::NANDDir) + MII_SAVE_DATABASE_PATH;
+    return FileUtil::Exists(path) && FileUtil::Delete(path);
+}
+
+void MiiManager::WriteToFile() {
+    const auto raw_path =
+        FileUtil::GetUserPath(FileUtil::UserPath::NANDDir) + "/system/save/8000000000000030";
+    if (FileUtil::Exists(raw_path) && !FileUtil::IsDirectory(raw_path))
+        FileUtil::Delete(raw_path);
+
+    const auto path = FileUtil::GetUserPath(FileUtil::UserPath::NANDDir) + MII_SAVE_DATABASE_PATH;
+
+    if (!FileUtil::CreateFullPath(path)) {
+        LOG_WARNING(Service_Mii,
+                    "Failed to create full path of MiiDatabase.dat. Create the directory "
+                    "nand/system/save/8000000000000030 to mitigate this "
+                    "issue.");
+        return;
+    }
+
+    FileUtil::IOFile save(path, "wb");
+
+    if (!save.IsOpen()) {
+        LOG_WARNING(Service_Mii, "Failed to write save data to file... No changes to user data "
+                                 "made in current session will be saved.");
+        return;
+    }
+
+    save.Resize(sizeof(MiiDatabase));
+    if (save.WriteBytes(&database, sizeof(MiiDatabase)) != sizeof(MiiDatabase)) {
+        LOG_WARNING(Service_Mii, "Failed to write all data to save file... Data may be malformed "
+                                 "and/or regenerated on next run.");
+        save.Resize(0);
+    }
+}
+
+void MiiManager::ReadFromFile() {
+    FileUtil::IOFile save(
+        FileUtil::GetUserPath(FileUtil::UserPath::NANDDir) + MII_SAVE_DATABASE_PATH, "rb");
+
+    if (!save.IsOpen()) {
+        LOG_WARNING(Service_ACC, "Failed to load profile data from save data... Generating new "
+                                 "blank Mii database with no Miis.");
+        std::memcpy(&database, &DEFAULT_MII_DATABASE, sizeof(MiiDatabase));
+        return;
+    }
+
+    if (save.ReadBytes(&database, sizeof(MiiDatabase)) != sizeof(MiiDatabase)) {
+        LOG_WARNING(Service_ACC, "MiiDatabase.dat is smaller than expected... Generating new blank "
+                                 "Mii database with no Miis.");
+        std::memcpy(&database, &DEFAULT_MII_DATABASE, sizeof(MiiDatabase));
+        return;
+    }
+
+    EnsureDatabasePartition();
+}
+
+MiiStoreData MiiManager::CreateMiiWithUniqueUUID() const {
+    auto new_mii = DEFAULT_MII;
+
+    do {
+        new_mii.uuid = Common::UUID::Generate();
+    } while (IndexOf(new_mii.uuid) != INVALID_INDEX);
+
+    return new_mii;
+}
+
+void MiiManager::EnsureDatabasePartition() {
+    std::stable_partition(database.miis.begin(), database.miis.end(),
+                          [](const MiiStoreData& elem) { return elem.uuid; });
+}
+
+} // namespace Service::Mii
diff --git a/src/core/hle/service/mii/mii_manager.h b/src/core/hle/service/mii/mii_manager.h
new file mode 100644
index 000000000..38ad78a0d
--- /dev/null
+++ b/src/core/hle/service/mii/mii_manager.h
@@ -0,0 +1,273 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/bit_field.h"
+#include "common/common_funcs.h"
+#include "common/uuid.h"
+
+namespace Service::Mii {
+
+constexpr std::size_t MAX_MIIS = 100;
+constexpr u32 INVALID_INDEX = 0xFFFFFFFF;
+
+struct RandomParameters {
+    u32 unknown_1;
+    u32 unknown_2;
+    u32 unknown_3;
+};
+static_assert(sizeof(RandomParameters) == 0xC, "RandomParameters has incorrect size.");
+
+enum class Source : u32 {
+    Database = 0,
+    Default = 1,
+    Account = 2,
+    Friend = 3,
+};
+
+std::ostream& operator<<(std::ostream& os, Source source);
+
+struct MiiInfo {
+    Common::UUID uuid;
+    std::array<char16_t, 11> name;
+    u8 font_region;
+    u8 favorite_color;
+    u8 gender;
+    u8 height;
+    u8 weight;
+    u8 mii_type;
+    u8 mii_region;
+    u8 face_type;
+    u8 face_color;
+    u8 face_wrinkle;
+    u8 face_makeup;
+    u8 hair_type;
+    u8 hair_color;
+    bool hair_flip;
+    u8 eye_type;
+    u8 eye_color;
+    u8 eye_scale;
+    u8 eye_aspect_ratio;
+    u8 eye_rotate;
+    u8 eye_x;
+    u8 eye_y;
+    u8 eyebrow_type;
+    u8 eyebrow_color;
+    u8 eyebrow_scale;
+    u8 eyebrow_aspect_ratio;
+    u8 eyebrow_rotate;
+    u8 eyebrow_x;
+    u8 eyebrow_y;
+    u8 nose_type;
+    u8 nose_scale;
+    u8 nose_y;
+    u8 mouth_type;
+    u8 mouth_color;
+    u8 mouth_scale;
+    u8 mouth_aspect_ratio;
+    u8 mouth_y;
+    u8 facial_hair_color;
+    u8 beard_type;
+    u8 mustache_type;
+    u8 mustache_scale;
+    u8 mustache_y;
+    u8 glasses_type;
+    u8 glasses_color;
+    u8 glasses_scale;
+    u8 glasses_y;
+    u8 mole_type;
+    u8 mole_scale;
+    u8 mole_x;
+    u8 mole_y;
+    INSERT_PADDING_BYTES(1);
+
+    std::u16string Name() const;
+};
+static_assert(sizeof(MiiInfo) == 0x58, "MiiInfo has incorrect size.");
+static_assert(std::has_unique_object_representations_v<MiiInfo>,
+              "All bits of MiiInfo must contribute to its value.");
+
+bool operator==(const MiiInfo& lhs, const MiiInfo& rhs);
+bool operator!=(const MiiInfo& lhs, const MiiInfo& rhs);
+
+#pragma pack(push, 4)
+struct MiiInfoElement {
+    MiiInfo info;
+    Source source;
+};
+static_assert(sizeof(MiiInfoElement) == 0x5C, "MiiInfoElement has incorrect size.");
+
+struct MiiStoreBitFields {
+    union {
+        u32 word_0;
+
+        BitField<24, 8, u32> hair_type;
+        BitField<23, 1, u32> mole_type;
+        BitField<16, 7, u32> height;
+        BitField<15, 1, u32> hair_flip;
+        BitField<8, 7, u32> weight;
+        BitField<0, 7, u32> hair_color;
+    };
+
+    union {
+        u32 word_1;
+
+        BitField<31, 1, u32> gender;
+        BitField<24, 7, u32> eye_color;
+        BitField<16, 7, u32> eyebrow_color;
+        BitField<8, 7, u32> mouth_color;
+        BitField<0, 7, u32> facial_hair_color;
+    };
+
+    union {
+        u32 word_2;
+
+        BitField<31, 1, u32> mii_type;
+        BitField<24, 7, u32> glasses_color;
+        BitField<22, 2, u32> font_region;
+        BitField<16, 6, u32> eye_type;
+        BitField<14, 2, u32> mii_region;
+        BitField<8, 6, u32> mouth_type;
+        BitField<5, 3, u32> glasses_scale;
+        BitField<0, 5, u32> eye_y;
+    };
+
+    union {
+        u32 word_3;
+
+        BitField<29, 3, u32> mustache_type;
+        BitField<24, 5, u32> eyebrow_type;
+        BitField<21, 3, u32> beard_type;
+        BitField<16, 5, u32> nose_type;
+        BitField<13, 3, u32> mouth_aspect;
+        BitField<8, 5, u32> nose_y;
+        BitField<5, 3, u32> eyebrow_aspect;
+        BitField<0, 5, u32> mouth_y;
+    };
+
+    union {
+        u32 word_4;
+
+        BitField<29, 3, u32> eye_rotate;
+        BitField<24, 5, u32> mustache_y;
+        BitField<21, 3, u32> eye_aspect;
+        BitField<16, 5, u32> glasses_y;
+        BitField<13, 3, u32> eye_scale;
+        BitField<8, 5, u32> mole_x;
+        BitField<0, 5, u32> mole_y;
+    };
+
+    union {
+        u32 word_5;
+
+        BitField<24, 5, u32> glasses_type;
+        BitField<20, 4, u32> face_type;
+        BitField<16, 4, u32> favorite_color;
+        BitField<12, 4, u32> face_wrinkle;
+        BitField<8, 4, u32> face_color;
+        BitField<4, 4, u32> eye_x;
+        BitField<0, 4, u32> face_makeup;
+    };
+
+    union {
+        u32 word_6;
+
+        BitField<28, 4, u32> eyebrow_rotate;
+        BitField<24, 4, u32> eyebrow_scale;
+        BitField<20, 4, u32> eyebrow_y;
+        BitField<16, 4, u32> eyebrow_x;
+        BitField<12, 4, u32> mouth_scale;
+        BitField<8, 4, u32> nose_scale;
+        BitField<4, 4, u32> mole_scale;
+        BitField<0, 4, u32> mustache_scale;
+    };
+};
+static_assert(sizeof(MiiStoreBitFields) == 0x1C, "MiiStoreBitFields has incorrect size.");
+static_assert(std::is_trivially_copyable_v<MiiStoreBitFields>,
+              "MiiStoreBitFields is not trivially copyable.");
+
+struct MiiStoreData {
+    // This corresponds to the above structure MiiStoreBitFields. I did it like this because the
+    // BitField<> type makes this (and any thing that contains it) not trivially copyable, which is
+    // not suitable for our uses.
+    std::array<u8, 0x1C> data;
+    static_assert(sizeof(MiiStoreBitFields) == sizeof(data), "data field has incorrect size.");
+
+    std::array<char16_t, 10> name;
+    Common::UUID uuid;
+    u16 crc_1;
+    u16 crc_2;
+
+    std::u16string Name() const;
+};
+static_assert(sizeof(MiiStoreData) == 0x44, "MiiStoreData has incorrect size.");
+
+struct MiiStoreDataElement {
+    MiiStoreData data;
+    Source source;
+};
+static_assert(sizeof(MiiStoreDataElement) == 0x48, "MiiStoreDataElement has incorrect size.");
+
+struct MiiDatabase {
+    u32 magic; // 'NFDB'
+    std::array<MiiStoreData, MAX_MIIS> miis;
+    INSERT_PADDING_BYTES(1);
+    u8 count;
+    u16 crc;
+};
+static_assert(sizeof(MiiDatabase) == 0x1A98, "MiiDatabase has incorrect size.");
+#pragma pack(pop)
+
+// The Mii manager is responsible for loading and storing the Miis to the database in NAND along
+// with providing an easy interface for HLE emulation of the mii service.
+class MiiManager {
+public:
+    MiiManager();
+    ~MiiManager();
+
+    MiiInfo CreateRandom(RandomParameters params);
+    MiiInfo CreateDefault(u32 index);
+
+    bool CheckUpdatedFlag() const;
+    void ResetUpdatedFlag();
+
+    bool IsTestModeEnabled() const;
+
+    bool Empty() const;
+    bool Full() const;
+
+    void Clear();
+
+    u32 Size() const;
+
+    MiiInfo GetInfo(u32 index) const;
+    MiiInfoElement GetInfoElement(u32 index) const;
+    MiiStoreData GetStoreData(u32 index) const;
+    MiiStoreDataElement GetStoreDataElement(u32 index) const;
+
+    bool Remove(Common::UUID uuid);
+    u32 IndexOf(Common::UUID uuid) const;
+    u32 IndexOf(const MiiInfo& info) const;
+
+    bool Move(Common::UUID uuid, u32 new_index);
+    bool AddOrReplace(const MiiStoreData& data);
+
+    bool DestroyFile();
+    bool DeleteFile();
+
+private:
+    void WriteToFile();
+    void ReadFromFile();
+
+    MiiStoreData CreateMiiWithUniqueUUID() const;
+
+    void EnsureDatabasePartition();
+
+    MiiDatabase database;
+    bool updated_flag = false;
+    bool is_test_mode_enabled = false;
+};
+
+}; // namespace Service::Mii