/*
 * Copyright (c) 2018 Atmosphère-NX
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#include <switch.h>
#include <stratosphere.hpp>
#include <atomic>
#include <algorithm>

#include "sm_mitm.h"
#include "debug.hpp"
#include "fsmitm_utils.hpp"

static FsFileSystem g_sd_filesystem = {0};
static std::vector<u64> g_mitm_flagged_tids;
static std::atomic_bool g_has_initialized = false;

static bool IsHexadecimal(const char *str) {
    while (*str) {
        if (isxdigit(*str)) {
            str++;
        } else {
            return false;
        }
    }
    return true;
}

void Utils::InitializeSdThreadFunc(void *args) {
    /* Get required services. */
    Handle tmp_hnd = 0;
    static const char * const required_active_services[] = {"pcv", "gpio", "pinmux", "psc:c"};
    for (unsigned int i = 0; i < sizeof(required_active_services) / sizeof(required_active_services[0]); i++) {
        if (R_FAILED(smGetServiceOriginal(&tmp_hnd, smEncodeName(required_active_services[i])))) {
            /* TODO: Panic */
        } else {
            svcCloseHandle(tmp_hnd);   
        }
    }
    
    /* Mount SD. */
    while (R_FAILED(fsMountSdcard(&g_sd_filesystem))) {
        svcSleepThread(1000ULL);
    }
    
    /* Check for MitM flags. */
    FsDir titles_dir;
    if (R_SUCCEEDED(fsFsOpenDirectory(&g_sd_filesystem, "/atmosphere/titles", FS_DIROPEN_DIRECTORY, &titles_dir))) {
        FsDirectoryEntry dir_entry;
        FsFile f;
        u64 read_entries;
        while (R_SUCCEEDED((fsDirRead(&titles_dir, 0, &read_entries, 1, &dir_entry))) && read_entries == 1) {
            if (strlen(dir_entry.name) == 0x10 && IsHexadecimal(dir_entry.name)) {
                u64 title_id = strtoul(dir_entry.name, NULL, 16);
                char title_path[FS_MAX_PATH] = {0};
                strcpy(title_path, "/atmosphere/titles/");
                strcat(title_path, dir_entry.name);
                strcat(title_path, "/fsmitm.flag");
                if (R_SUCCEEDED(fsFsOpenFile(&g_sd_filesystem, title_path, FS_OPEN_READ, &f))) {
                    g_mitm_flagged_tids.push_back(title_id);
                    fsFileClose(&f);
                }
            }
        }
        fsDirClose(&titles_dir);
    }
    
    g_has_initialized = true;
    
    svcExitThread();
}

bool Utils::IsSdInitialized() {
    return g_has_initialized;
}

Result Utils::OpenSdFile(const char *fn, int flags, FsFile *out) {
    if (!IsSdInitialized()) {
        return 0xFA202;
    }
    
    return fsFsOpenFile(&g_sd_filesystem, fn, flags, out);
}

Result Utils::OpenSdFileForAtmosphere(u64 title_id, const char *fn, int flags, FsFile *out) {
    if (!IsSdInitialized()) {
        return 0xFA202;
    }
    
    char path[FS_MAX_PATH];
    if (*fn == '/') {
        snprintf(path, sizeof(path), "/atmosphere/titles/%016lx%s", title_id, fn);
    } else {
        snprintf(path, sizeof(path), "/atmosphere/titles/%016lx/%s", title_id, fn);
    }
    return fsFsOpenFile(&g_sd_filesystem, path, flags, out);
}

Result Utils::OpenRomFSSdFile(u64 title_id, const char *fn, int flags, FsFile *out) {
    if (!IsSdInitialized()) {
        return 0xFA202;
    }
    
    return OpenRomFSFile(&g_sd_filesystem, title_id, fn, flags, out);
}

Result Utils::OpenSdDir(const char *path, FsDir *out) {
    if (!IsSdInitialized()) {
        return 0xFA202;
    }
    
    return fsFsOpenDirectory(&g_sd_filesystem, path, FS_DIROPEN_DIRECTORY | FS_DIROPEN_FILE, out);
}

Result Utils::OpenSdDirForAtmosphere(u64 title_id, const char *path, FsDir *out) {
    if (!IsSdInitialized()) {
        return 0xFA202;
    }
    
    char safe_path[FS_MAX_PATH];
    if (*path == '/') {
        snprintf(safe_path, sizeof(safe_path), "/atmosphere/titles/%016lx%s", title_id, path);
    } else {
        snprintf(safe_path, sizeof(safe_path), "/atmosphere/titles/%016lx/%s", title_id, path);
    }
    return fsFsOpenDirectory(&g_sd_filesystem, safe_path, FS_DIROPEN_DIRECTORY | FS_DIROPEN_FILE, out);
}

Result Utils::OpenRomFSSdDir(u64 title_id, const char *path, FsDir *out) {
    if (!IsSdInitialized()) {
        return 0xFA202;
    }
    
    return OpenRomFSDir(&g_sd_filesystem, title_id, path, out);
}


Result Utils::OpenRomFSFile(FsFileSystem *fs, u64 title_id, const char *fn, int flags, FsFile *out) {
    char path[FS_MAX_PATH];
    if (*fn == '/') {
        snprintf(path, sizeof(path), "/atmosphere/titles/%016lx/romfs%s", title_id, fn);
    } else {
        snprintf(path, sizeof(path), "/atmosphere/titles/%016lx/romfs/%s", title_id, fn);
    }
    return fsFsOpenFile(fs, path, flags, out);
}

Result Utils::OpenRomFSDir(FsFileSystem *fs, u64 title_id, const char *path, FsDir *out) {
    char safe_path[FS_MAX_PATH];
    if (*path == '/') {
        snprintf(safe_path, sizeof(safe_path), "/atmosphere/titles/%016lx/romfs%s", title_id, path);
    } else {
        snprintf(safe_path, sizeof(safe_path), "/atmosphere/titles/%016lx/romfs/%s", title_id, path);
    }
    return fsFsOpenDirectory(fs, safe_path, FS_DIROPEN_DIRECTORY | FS_DIROPEN_FILE, out);
}

Result Utils::HasSdRomfsContent(u64 title_id, bool *out) {
    Result rc;
    FsDir dir;
    if (R_FAILED((rc = Utils::OpenRomFSSdDir(title_id, "", &dir)))) {
        return rc;
    }
    
    FsDirectoryEntry dir_entry;
    u64 read_entries;
    if (R_SUCCEEDED((rc = fsDirRead(&dir, 0, &read_entries, 1, &dir_entry)))) {
        *out = (read_entries == 1);
    }
    fsDirClose(&dir);
    return rc;
}

bool Utils::HasSdMitMFlag(u64 tid) {
    if (IsSdInitialized()) {
        return std::find(g_mitm_flagged_tids.begin(), g_mitm_flagged_tids.end(), tid) != g_mitm_flagged_tids.end();
    }
    return false;
}