/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

#include "SDL_internal.h"

#include "../SDL_sysstorage.h"

#if defined(_WIN64)
#define SDL_DRIVER_STEAMAPI_DYNAMIC "steam_api64.dll"
#elif defined(_WIN32)
#define SDL_DRIVER_STEAMAPI_DYNAMIC "steam_api.dll"
#elif defined(__APPLE__)
#define SDL_DRIVER_STEAMAPI_DYNAMIC "libsteam_api.dylib"
#else
#define SDL_DRIVER_STEAMAPI_DYNAMIC "libsteam_api.so"
#endif

SDL_ELF_NOTE_DLOPEN(
    "storage-steam",
    "Support for Steam user storage",
    SDL_ELF_NOTE_DLOPEN_PRIORITY_SUGGESTED,
    SDL_DRIVER_STEAMAPI_DYNAMIC
);

// !!! FIXME: Async API can use SteamRemoteStorage_ReadFileAsync
// !!! FIXME: Async API can use SteamRemoteStorage_WriteFileAsync

#define STEAM_PROC(ret, func, parms) \
    typedef ret (*steamfntype_##func) parms;
#include "SDL_steamstorage_proc.h"

typedef struct STEAM_RemoteStorage
{
    SDL_SharedObject *libsteam_api;
    #define STEAM_PROC(ret, func, parms) \
        steamfntype_##func func;
    #include "SDL_steamstorage_proc.h"
} STEAM_RemoteStorage;

static SDL_AtomicInt SDL_steam_storage_refcount;

static bool STEAM_CloseStorage(void *userdata)
{
    bool result = true;
    STEAM_RemoteStorage *steam = (STEAM_RemoteStorage *)userdata;
    void *steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
    bool end_batch = SDL_AtomicDecRef(&SDL_steam_storage_refcount);
    if (steamremotestorage == NULL) {
        result = SDL_SetError("SteamRemoteStorage unavailable");
    } else if (end_batch) {
        if (!steam->SteamAPI_ISteamRemoteStorage_EndFileWriteBatch(steamremotestorage)) {
            result = SDL_SetError("SteamRemoteStorage()->EndFileWriteBatch() failed");
        }
    }
    SDL_UnloadObject(steam->libsteam_api);
    SDL_free(steam);
    return result;
}

static bool STEAM_StorageReady(void *userdata)
{
    return true;
}

static char *GetNormalizedStoragePath(const char *path, bool add_separator)
{
    if (SDL_strcmp(path, ".") == 0) {
        path = "";
    } else {
        while (*path == '/') {
            ++path;
        }
    }

    size_t pathlen = SDL_strlen(path);
    while (pathlen > 0 && path[pathlen - 1] == '/') {
        --pathlen;
    }

    char *normalized = (char *)SDL_malloc(pathlen + add_separator + 1);
    if (normalized) {
        SDL_memcpy(normalized, path, pathlen);
        if (add_separator) {
            normalized[pathlen++] = '/';
        }
        normalized[pathlen] = '\0';
    }
    return normalized;
}

static bool STEAM_EnumerateStorageDirectory(void *userdata, const char *path, SDL_EnumerateDirectoryCallback callback, void *callback_userdata)
{
    bool result = true;
    STEAM_RemoteStorage *steam = (STEAM_RemoteStorage *)userdata;
    void *steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
    if (steamremotestorage == NULL) {
        return SDL_SetError("SteamRemoteStorage unavailable");
    }

    char *dirname = GetNormalizedStoragePath(path, true);
    if (!dirname) {
        return false;
    }
    size_t dirlen = SDL_strlen(dirname);

    bool done = false;
    Sint32 count = steam->SteamAPI_ISteamRemoteStorage_GetFileCount(steamremotestorage);
    for (Sint32 i = count; i-- && !done; ) {
        const char *file = steam->SteamAPI_ISteamRemoteStorage_GetFileNameAndSize(steamremotestorage, i, NULL);
        if (!file) {
            continue;
        }

        const char *fname;
        if (dirlen > 1) {
            // Make sure the directory matches
            if (SDL_strncmp(dirname, file, dirlen) != 0) {
                continue;
            }
            fname = file + dirlen;
        } else {
            fname = file;
        }

        // Make sure this is a file in the current directory
        if (SDL_strchr(fname, '/') != NULL) {
            continue;
        }

        switch (callback(callback_userdata, dirname, fname)) {
        case SDL_ENUM_SUCCESS:
            done = true;
            break;
        case SDL_ENUM_FAILURE:
            result = false;
            done = true;
            break;
        default:
            break;
        }
    }
    SDL_free(dirname);

    return result;
}

static bool STEAM_GetStoragePathInfo(void *userdata, const char *path, SDL_PathInfo *info)
{
    STEAM_RemoteStorage *steam = (STEAM_RemoteStorage *)userdata;
    void *steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
    if (steamremotestorage == NULL) {
        return SDL_SetError("SteamRemoteStorage unavailable");
    }

    if (!steam->SteamAPI_ISteamRemoteStorage_FileExists(steamremotestorage, path)) {
        return SDL_SetError("Can't stat");
    }

    if (info) {
        SDL_zerop(info);
        info->type = SDL_PATHTYPE_FILE;
        info->size = steam->SteamAPI_ISteamRemoteStorage_GetFileSize(steamremotestorage, path);
        Sint64 mtime = steam->SteamAPI_ISteamRemoteStorage_GetFileTimestamp(steamremotestorage, path);
        info->modify_time = (SDL_Time)SDL_SECONDS_TO_NS(mtime);
    }
    return true;
}

static bool STEAM_ReadStorageFile(void *userdata, const char *path, void *destination, Uint64 length)
{
    bool result = false;
    STEAM_RemoteStorage *steam = (STEAM_RemoteStorage *)userdata;
    void *steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
    if (steamremotestorage == NULL) {
        return SDL_SetError("SteamRemoteStorage unavailable");
    }
    if (length > SDL_MAX_SINT32) {
        return SDL_SetError("SteamRemoteStorage only supports INT32_MAX read size");
    }
    if (steam->SteamAPI_ISteamRemoteStorage_FileRead(steamremotestorage, path, destination, (Sint32) length) == length) {
        result = true;
    } else {
        SDL_SetError("SteamRemoteStorage()->FileRead() failed");
    }
    return result;
}

static bool STEAM_WriteStorageFile(void *userdata, const char *path, const void *source, Uint64 length)
{
    bool result = false;
    STEAM_RemoteStorage *steam = (STEAM_RemoteStorage *)userdata;
    void *steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
    if (steamremotestorage == NULL) {
        return SDL_SetError("SteamRemoteStorage unavailable");
    }
    if (length > SDL_MAX_SINT32) {
        return SDL_SetError("SteamRemoteStorage only supports INT32_MAX write size");
    }
    if (steam->SteamAPI_ISteamRemoteStorage_FileWrite(steamremotestorage, path, source, (Sint32)length)) {
        result = true;
    } else {
        SDL_SetError("SteamRemoteStorage()->FileWrite() failed");
    }
    return result;
}

static bool STEAM_RemoveStoragePath(void *userdata, const char *path)
{
    STEAM_RemoteStorage *steam = (STEAM_RemoteStorage *)userdata;
    void *steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
    if (steamremotestorage == NULL) {
        return SDL_SetError("SteamRemoteStorage unavailable");
    }
    if (!steam->SteamAPI_ISteamRemoteStorage_FileDelete(steamremotestorage, path)) {
        return SDL_SetError("SteamRemoteStorage()->FileDelete() failed");
    }
    return true;
}

static Uint64 STEAM_GetStorageSpaceRemaining(void *userdata)
{
    Uint64 total, remaining;
    STEAM_RemoteStorage *steam = (STEAM_RemoteStorage *)userdata;
    void *steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
    if (steamremotestorage == NULL) {
        SDL_SetError("SteamRemoteStorage unavailable");
        return 0;
    }
    if (!steam->SteamAPI_ISteamRemoteStorage_GetQuota(steamremotestorage, &total, &remaining)) {
        SDL_SetError("SteamRemoteStorage()->GetQuota() failed");
        return 0;
    }
    return remaining;
}

static const SDL_StorageInterface STEAM_user_iface = {
    sizeof(SDL_StorageInterface),
    STEAM_CloseStorage,
    STEAM_StorageReady,
    STEAM_EnumerateStorageDirectory,
    STEAM_GetStoragePathInfo,
    STEAM_ReadStorageFile,
    STEAM_WriteStorageFile,
    NULL,   // mkdir
    STEAM_RemoveStoragePath,
    NULL,   // rename
    NULL,   // copy
    STEAM_GetStorageSpaceRemaining
};

static SDL_Storage *STEAM_User_Create(const char *org, const char *app, SDL_PropertiesID props)
{
    SDL_Storage *result;
    STEAM_RemoteStorage *steam;
    void *steamremotestorage;

    steam = (STEAM_RemoteStorage *)SDL_malloc(sizeof(STEAM_RemoteStorage));
    if (steam == NULL) {
        return NULL;
    }

    steam->libsteam_api = SDL_LoadObject(SDL_DRIVER_STEAMAPI_DYNAMIC);
    if (steam->libsteam_api == NULL) {
        SDL_free(steam);
        return NULL;
    }

    #define STEAM_PROC(ret, func, parms) \
        steam->func = (steamfntype_##func) SDL_LoadFunction(steam->libsteam_api, #func); \
        if (steam->func == NULL) { \
            SDL_SetError("Could not load function " #func); \
            goto steamfail; \
        }
    #include "SDL_steamstorage_proc.h"

    steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
    if (steamremotestorage == NULL) {
        SDL_SetError("SteamRemoteStorage unavailable");
        goto steamfail;
    }
    if (!steam->SteamAPI_ISteamRemoteStorage_IsCloudEnabledForAccount(steamremotestorage)) {
        SDL_SetError("Steam cloud is disabled for this user");
        goto steamfail;
    }
    if (!steam->SteamAPI_ISteamRemoteStorage_IsCloudEnabledForApp(steamremotestorage)) {
        SDL_SetError("Steam cloud is disabled for this application");
        goto steamfail;
    }

    result = SDL_OpenStorage(&STEAM_user_iface, steam);
    if (!result) {
        goto steamfail;
    }

    if (SDL_AtomicIncRef(&SDL_steam_storage_refcount) == 0) {
        if (!steam->SteamAPI_ISteamRemoteStorage_BeginFileWriteBatch(steamremotestorage)) {
            // We probably already have a batch in progress (maybe we crashed earlier?)
        }
    }
    return result;

steamfail:
    SDL_UnloadObject(steam->libsteam_api);
    SDL_free(steam);
    return NULL;
}

UserStorageBootStrap STEAM_userbootstrap = {
    "steam",
    "SDL Steam user storage driver",
    STEAM_User_Create
};
