/*
 * 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 <cstring>
#include <switch.h>
#include <stratosphere.hpp>
#include <strings.h>
#include <vector>
#include <algorithm>
#include <map>

#include "ldr_registration.hpp"
#include "ldr_content_management.hpp"
#include "ldr_hid.hpp"
#include "ldr_npdm.hpp"

#include "ini.h"

static FsFileSystem g_CodeFileSystem = {0};
static FsFileSystem g_HblFileSystem = {0};

static std::vector<u64> g_created_titles;
static bool g_has_initialized_fs_dev = false;

/* Default to Key R, hold disables override, HBL at atmosphere/hbl.nsp. */
static bool g_mounted_hbl_nsp = false;
static char g_hbl_sd_path[FS_MAX_PATH+1] = "@Sdcard:/atmosphere/hbl.nsp\x00";

static OverrideKey g_default_override_key = {
    .key_combination = KEY_L,
    .override_by_default = true
};

struct HblOverrideConfig {
    OverrideKey override_key;
    u64 title_id;
    bool override_any_app;
};

static HblOverrideConfig g_hbl_override_config = {
    .override_key = {
        .key_combination = KEY_R,
        .override_by_default = true
    },
    .title_id = 0x010000000000100D,
    .override_any_app = false
};

/* Static buffer for loader.ini contents at runtime. */
static char g_config_ini_data[0x800];

/* SetExternalContentSource extension */
static std::map<u64, ContentManagement::ExternalContentSource> g_external_content_sources;

Result ContentManagement::MountCode(u64 tid, FsStorageId sid) {
    char path[FS_MAX_PATH] = {0};
    Result rc;

    /* We defer SD card mounting, so if relevant ensure it is mounted. */
    if (!g_has_initialized_fs_dev) {
        TryMountSdCard();
    }

    if (g_has_initialized_fs_dev) {
        RefreshConfigurationData();
    }

    if (ShouldOverrideContentsWithSD(tid) && R_SUCCEEDED(MountCodeNspOnSd(tid))) {
        return 0x0;
    }

    if (R_FAILED(rc = ResolveContentPath(path, tid, sid))) {
        return rc;
    }

    /* Fix up path. */
    for (unsigned int i = 0; i < FS_MAX_PATH && path[i] != '\x00'; i++) {
        if (path[i] == '\\') {
            path[i] = '/';
        }
    }

    /* Always re-initialize fsp-ldr, in case it's closed */
    if (R_FAILED(rc = fsldrInitialize())) {
        return rc;
    }

    if (R_FAILED(rc = fsldrOpenCodeFileSystem(tid, path, &g_CodeFileSystem))) {
        fsldrExit();
        return rc;
    }

    fsdevMountDevice("code", g_CodeFileSystem);
    TryMountHblNspOnSd();

    fsldrExit();
    return rc;
}

Result ContentManagement::UnmountCode() {
    if (g_mounted_hbl_nsp) {
        fsdevUnmountDevice("hbl");
        g_mounted_hbl_nsp = false;
    }
    fsdevUnmountDevice("code");
    return 0;
}


void ContentManagement::TryMountHblNspOnSd() {
    char path[FS_MAX_PATH + 1];
    strncpy(path, g_hbl_sd_path, FS_MAX_PATH);
    path[FS_MAX_PATH] = 0;
    for (unsigned int i = 0; i < FS_MAX_PATH && path[i] != '\x00'; i++) {
        if (path[i] == '\\') {
            path[i] = '/';
        }
    }
    if (g_has_initialized_fs_dev && !g_mounted_hbl_nsp && R_SUCCEEDED(fsOpenFileSystemWithId(&g_HblFileSystem, 0, FsFileSystemType_ApplicationPackage, path))) {
        fsdevMountDevice("hbl", g_HblFileSystem);
        g_mounted_hbl_nsp = true;
    }
}

Result ContentManagement::MountCodeNspOnSd(u64 tid) {
    char path[FS_MAX_PATH+1] = {0};
    snprintf(path, FS_MAX_PATH, "@Sdcard:/atmosphere/titles/%016lx/exefs.nsp", tid);
    Result rc = fsOpenFileSystemWithId(&g_CodeFileSystem, 0, FsFileSystemType_ApplicationPackage, path);

    if (R_SUCCEEDED(rc)) {
        fsdevMountDevice("code", g_CodeFileSystem);
        TryMountHblNspOnSd();
    }

    return rc;
}

Result ContentManagement::MountCodeForTidSid(Registration::TidSid *tid_sid) {
    return MountCode(tid_sid->title_id, tid_sid->storage_id);
}

Result ContentManagement::ResolveContentPath(char *out_path, u64 tid, FsStorageId sid) {
    Result rc;
    LrRegisteredLocationResolver reg;
    LrLocationResolver lr;
    char path[FS_MAX_PATH] = {0};

    /* Try to get the path from the registered resolver. */
    if (R_FAILED(rc = lrOpenRegisteredLocationResolver(&reg))) {
        return rc;
    }

    if (R_SUCCEEDED(rc = lrRegLrResolveProgramPath(&reg, tid, path))) {
        strncpy(out_path, path, FS_MAX_PATH);
    } else if (rc != ResultLrProgramNotFound) {
        return rc;
    }

    serviceClose(&reg.s);
    if (R_SUCCEEDED(rc)) {
        return rc;
    }

    /* If getting the path from the registered resolver fails, fall back to the normal resolver. */
    if (R_FAILED(rc = lrOpenLocationResolver(sid, &lr))) {
        return rc;
    }

    if (R_SUCCEEDED(rc = lrLrResolveProgramPath(&lr, tid, path))) {
        strncpy(out_path, path, FS_MAX_PATH);
    }

    serviceClose(&lr.s);

    return rc;
}

Result ContentManagement::ResolveContentPathForTidSid(char *out_path, Registration::TidSid *tid_sid) {
    return ResolveContentPath(out_path, tid_sid->title_id, tid_sid->storage_id);
}

Result ContentManagement::RedirectContentPath(const char *path, u64 tid, FsStorageId sid) {
    Result rc;
    LrLocationResolver lr;

    if (R_FAILED(rc = lrOpenLocationResolver(sid, &lr))) {
        return rc;
    }

    rc = lrLrRedirectProgramPath(&lr, tid, path);

    serviceClose(&lr.s);

    return rc;
}

Result ContentManagement::RedirectContentPathForTidSid(const char *path, Registration::TidSid *tid_sid) {
    return RedirectContentPath(path, tid_sid->title_id, tid_sid->storage_id);
}

void ContentManagement::RedirectHtmlDocumentPathForHbl(u64 tid, FsStorageId sid) {
    LrLocationResolver lr;
    char path[FS_MAX_PATH] = {0};

    /* Open resolver. */
    if (R_FAILED(lrOpenLocationResolver(sid, &lr))) {
        return;
    }

    /* Ensure close on exit. */
    ON_SCOPE_EXIT { serviceClose(&lr.s); };

    /* Only redirect the HTML document path if there is not one already. */
    if (R_SUCCEEDED(lrLrResolveApplicationHtmlDocumentPath(&lr, tid, path))) {
        return;
    }

    /* We just need to set this to any valid NCA path. Let's use the executable path. */
    if (R_FAILED(lrLrResolveProgramPath(&lr, tid, path))) {
        return;
    }

    lrLrRedirectApplicationHtmlDocumentPath(&lr, tid, path);
}

bool ContentManagement::HasCreatedTitle(u64 tid) {
    return std::find(g_created_titles.begin(), g_created_titles.end(), tid) != g_created_titles.end();
}

void ContentManagement::SetCreatedTitle(u64 tid) {
    if (!HasCreatedTitle(tid)) {
        g_created_titles.push_back(tid);
    }
}

static OverrideKey ParseOverrideKey(const char *value) {
    OverrideKey cfg;

    /* Parse on by default. */
    if (value[0] == '!') {
        cfg.override_by_default = true;
        value++;
    } else {
        cfg.override_by_default = false;
    }

    /* Parse key combination. */
    if (strcasecmp(value, "A") == 0) {
        cfg.key_combination = KEY_A;
    } else if (strcasecmp(value, "B") == 0) {
        cfg.key_combination = KEY_B;
    } else if (strcasecmp(value, "X") == 0) {
        cfg.key_combination = KEY_X;
    } else if (strcasecmp(value, "Y") == 0) {
        cfg.key_combination = KEY_Y;
    } else if (strcasecmp(value, "LS") == 0) {
        cfg.key_combination = KEY_LSTICK;
    } else if (strcasecmp(value, "RS") == 0) {
        cfg.key_combination = KEY_RSTICK;
    } else if (strcasecmp(value, "L") == 0) {
        cfg.key_combination = KEY_L;
    } else if (strcasecmp(value, "R") == 0) {
        cfg.key_combination = KEY_R;
    } else if (strcasecmp(value, "ZL") == 0) {
        cfg.key_combination = KEY_ZL;
    } else if (strcasecmp(value, "ZR") == 0) {
        cfg.key_combination = KEY_ZR;
    } else if (strcasecmp(value, "PLUS") == 0) {
        cfg.key_combination = KEY_PLUS;
    } else if (strcasecmp(value, "MINUS") == 0) {
        cfg.key_combination = KEY_MINUS;
    } else if (strcasecmp(value, "DLEFT") == 0) {
        cfg.key_combination = KEY_DLEFT;
    } else if (strcasecmp(value, "DUP") == 0) {
        cfg.key_combination = KEY_DUP;
    } else if (strcasecmp(value, "DRIGHT") == 0) {
        cfg.key_combination = KEY_DRIGHT;
    } else if (strcasecmp(value, "DDOWN") == 0) {
        cfg.key_combination = KEY_DDOWN;
    } else if (strcasecmp(value, "SL") == 0) {
        cfg.key_combination = KEY_SL;
    } else if (strcasecmp(value, "SR") == 0) {
        cfg.key_combination = KEY_SR;
    } else {
        cfg.key_combination = 0;
    }

    return cfg;
}

static int LoaderIniHandler(void *user, const char *section, const char *name, const char *value) {
    /* Taken and modified, with love, from Rajkosto's implementation. */
    if (strcasecmp(section, "hbl_config") == 0) {
        if (strcasecmp(name, "title_id") == 0) {
            if (strcasecmp(value, "app") == 0) {
                /* DEPRECATED */
                g_hbl_override_config.override_any_app = true;
                g_hbl_override_config.title_id = 0;
            } else {
                u64 override_tid = strtoul(value, NULL, 16);
                if (override_tid != 0) {
                    g_hbl_override_config.title_id = override_tid;
                }
            }
        } else if (strcasecmp(name, "path") == 0) {
            while (*value == '/' || *value == '\\') {
                value++;
            }
            snprintf(g_hbl_sd_path, FS_MAX_PATH, "@Sdcard:/%s", value);
            g_hbl_sd_path[FS_MAX_PATH] = 0;
        } else if (strcasecmp(name, "override_key") == 0) {
            g_hbl_override_config.override_key = ParseOverrideKey(value);
        } else if (strcasecmp(name, "override_any_app") == 0) {
            if (strcasecmp(value, "true") == 0 || strcasecmp(value, "1") == 0) {
                g_hbl_override_config.override_any_app = true;
            } else if (strcasecmp(value, "false") == 0 || strcasecmp(value, "0") == 0) {
                g_hbl_override_config.override_any_app = false;
            } else {
                /* I guess we default to not changing the value? */
            }
        }
    } else if (strcasecmp(section, "default_config") == 0) {
        if (strcasecmp(name, "override_key") == 0) {
            g_default_override_key = ParseOverrideKey(value);
        }
    } else {
        return 0;
    }
    return 1;
}

static int LoaderTitleSpecificIniHandler(void *user, const char *section, const char *name, const char *value) {
    /* We'll output an override key when relevant. */
    OverrideKey *user_cfg = reinterpret_cast<OverrideKey *>(user);

    if (strcasecmp(section, "override_config") == 0) {
        if (strcasecmp(name, "override_key") == 0) {
            *user_cfg = ParseOverrideKey(value);
        }
    } else {
        return 0;
    }
    return 1;
}

void ContentManagement::RefreshConfigurationData() {
    FILE *config = fopen("sdmc:/atmosphere/loader.ini", "r");
    if (config == NULL) {
        return;
    }

    std::fill(g_config_ini_data, g_config_ini_data + 0x800, 0);
    fread(g_config_ini_data, 1, 0x7FF, config);
    fclose(config);

    ini_parse_string(g_config_ini_data, LoaderIniHandler, NULL);
}

void ContentManagement::TryMountSdCard() {
    /* Mount SD card, if psc, bus, and pcv have been created. */
    if (!g_has_initialized_fs_dev && HasCreatedTitle(0x0100000000000021) && HasCreatedTitle(0x010000000000000A) && HasCreatedTitle(0x010000000000001A)) {
        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])))) {
                return;
            } else {
                svcCloseHandle(tmp_hnd);
            }
        }

        if (R_SUCCEEDED(fsdevMountSdmc())) {
            g_has_initialized_fs_dev = true;
        }
    }
}

static bool IsHBLTitleId(u64 tid) {
    return ((g_hbl_override_config.override_any_app && IsApplicationTid(tid)) || (tid == g_hbl_override_config.title_id));
}

OverrideKey ContentManagement::GetTitleOverrideKey(u64 tid) {
    OverrideKey cfg = g_default_override_key;
    char path[FS_MAX_PATH+1] = {0};
    snprintf(path, FS_MAX_PATH, "sdmc:/atmosphere/titles/%016lx/config.ini", tid);


    FILE *config = fopen(path, "r");
    if (config != NULL) {
        ON_SCOPE_EXIT { fclose(config); };

        /* Parse current title ini. */
        ini_parse_file(config, LoaderTitleSpecificIniHandler, &cfg);
    }

    return cfg;
}

static bool ShouldOverrideContents(OverrideKey *cfg) {
    u64 kDown = 0;
    bool keys_triggered = (R_SUCCEEDED(HidManagement::GetKeysHeld(&kDown)) && ((kDown & cfg->key_combination) != 0));
    return g_has_initialized_fs_dev && (cfg->override_by_default ^ keys_triggered);
}

bool ContentManagement::ShouldOverrideContentsWithHBL(u64 tid) {
    if (g_mounted_hbl_nsp && tid >= 0x0100000000001000 && HasCreatedTitle(0x0100000000001000)) {
        /* Return whether we should override contents with HBL. */
        return IsHBLTitleId(tid) && ShouldOverrideContents(&g_hbl_override_config.override_key);
    } else {
        /* Don't override if we failed to mount HBL or haven't launched qlaunch. */
        return false;
    }
}

bool ContentManagement::ShouldOverrideContentsWithSD(u64 tid) {
    if (g_has_initialized_fs_dev) {
        if (tid >= 0x0100000000001000 && HasCreatedTitle(0x0100000000001000)) {
            /* Check whether we should override with non-HBL. */
            OverrideKey title_cfg = GetTitleOverrideKey(tid);
            return ShouldOverrideContents(&title_cfg);
        } else {
            /* Always redirect before qlaunch. */
            return true;
        }
    } else {
        /* Never redirect before we can do so. */
        return false;
    }
}

/* SetExternalContentSource extension */
ContentManagement::ExternalContentSource *ContentManagement::GetExternalContentSource(u64 tid) {
    auto i = g_external_content_sources.find(tid);
    if (i == g_external_content_sources.end()) {
        return nullptr;
    } else {
        return &i->second;
    }
}

Result ContentManagement::SetExternalContentSource(u64 tid, FsFileSystem filesystem) {
    if (g_external_content_sources.size() >= 16) {
        return ResultLoaderTooManyArguments; /* TODO: Is this an appropriate error? */
    }

    /* Remove any existing ECS for this title. */
    ClearExternalContentSource(tid);

    char mountpoint[32];
    ExternalContentSource::GenerateMountpointName(tid, mountpoint, sizeof(mountpoint));
    if (fsdevMountDevice(mountpoint, filesystem) == -1) {
        return ResultFsMountNameAlreadyExists;
    }
    g_external_content_sources.emplace(
        std::piecewise_construct,
        std::make_tuple(tid),
        std::make_tuple(tid, mountpoint));

    return 0;
}

void ContentManagement::ClearExternalContentSource(u64 tid) {
    auto i = g_external_content_sources.find(tid);
    if (i != g_external_content_sources.end()) {
        g_external_content_sources.erase(i);
    }
}

void ContentManagement::ExternalContentSource::GenerateMountpointName(u64 tid, char *out, size_t max_length) {
    snprintf(out, max_length, "ecs-%016lx", tid);
}

ContentManagement::ExternalContentSource::ExternalContentSource(u64 tid, const char *mountpoint) : tid(tid) {
    strncpy(this->mountpoint, mountpoint, sizeof(this->mountpoint));
    NpdmUtils::InvalidateCache(tid);
}

ContentManagement::ExternalContentSource::~ExternalContentSource() {
    fsdevUnmountDevice(mountpoint);
}