<?php

namespace App\Console\Commands;

use Illuminate\Console\Command;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;
use App\Models\ForumCategory;
use App\Models\ForumThread;
use App\Models\ForumPost;
use Exception;
use App\Services\BbcodeConverter;

class ForumMigrateOld extends Command
{
    protected $signature = 'forum:migrate-old {--dry-run} {--only=} {--limit=} {--chunk=500} {--report}';

    protected $description = 'Migrate legacy forum data from legacy DB into new forum tables';

    protected string $logPath;

    public function __construct()
    {
        parent::__construct();
        $this->logPath = storage_path('logs/forum_migration.log');
    }

    public function handle(): int
    {
        $this->info('Starting forum migration');
        $this->log('Starting forum migration');

        $dry = $this->option('dry-run');
        $only = $this->option('only');
        $chunk = (int)$this->option('chunk');

        try {
            if (!$only || $only === 'categories') {
                $this->migrateCategories($dry);
            }

            if (!$only || $only === 'threads') {
                $this->migrateThreads($dry, $chunk);
            }

            if (!$only || $only === 'posts') {
                $this->migratePosts($dry, $chunk);
            }

            if (!$only || $only === 'gallery') {
                $this->migrateGallery($dry, $chunk);
            }

            if ($this->option('report')) {
                $this->generateReport();
            }

            $this->info('Forum migration finished');
            $this->log('Forum migration finished');
            return 0;
        } catch (Exception $e) {
            $this->error('Migration failed: ' . $e->getMessage());
            $this->log('Migration failed: ' . $e->getMessage());
            return 1;
        }
    }

    protected function migrateCategories(bool $dry)
    {
        $this->info('Migrating categories');
        $legacy = DB::connection('legacy');

        $roots = $legacy->table('forum_topics')
            ->select('root_id')
            ->distinct()
            ->where('root_id', '>', 0)
            ->pluck('root_id');

        $this->info('Found ' . $roots->count() . ' legacy root ids');

        foreach ($roots as $rootId) {
            $row = $legacy->table('forum_topics')->where('topic_id', $rootId)->first();
            $name = $row->topic ?? 'Category ' . $rootId;
            $slug = Str::slug(substr($name, 0, 150));

            $this->line("-> root {$rootId}: {$name}");

            if ($dry) {
                $this->log("[dry] create category {$name} ({$slug})");
                continue;
            }

            ForumCategory::updateOrCreate(
                ['id' => $rootId],
                ['name' => $name, 'slug' => $slug]
            );
        }

        $this->info('Categories migrated');
    }

    protected function migrateThreads(bool $dry, int $chunk)
    {
        $this->info('Migrating threads');
        $legacy = DB::connection('legacy');

        $query = $legacy->table('forum_topics')->orderBy('topic_id');

        $total = $query->count();
        $this->info("Total threads to process: {$total}");

        $bar = $this->output->createProgressBar($total);
        $bar->start();

        // chunk by legacy primary key `topic_id`
        $query->chunkById($chunk, function ($rows) use ($dry, $bar) {
            foreach ($rows as $r) {
                $bar->advance();

                $data = [
                    'id' => $r->topic_id,
                    'category_id' => $this->resolveCategoryId($r->root_id ?? null, $r->topic_id),
                    // resolve user id or assign to system user (1) when missing or not found
                    'user_id' => $this->resolveUserId($r->user_id ?? null),
                    'title' => $r->topic,
                    'slug' => $this->uniqueSlug(Str::slug(substr($r->topic,0,200)) ?: 'thread-'.$r->topic_id, $r->topic_id),
                    'content' => $r->preview ?? '',
                    'views' => $r->views ?? 0,
                    'is_locked' => isset($r->open) ? !((bool)$r->open) : false,
                    'is_pinned' => false,
                    'visibility' => $this->mapPrivilegeToVisibility($r->privilege ?? 0),
                    'last_post_at' => $this->normalizeDate($r->last_update ?? null),
                ];

                if ($dry) {
                    $this->log('[dry] thread: ' . $r->topic_id . ' - ' . $r->topic);
                    continue;
                }

                ForumThread::updateOrCreate(['id' => $data['id']], $data);
            }
        }, 'topic_id');

        $bar->finish();
        $this->line('');
        $this->info('Threads migrated');
    }

    protected function migratePosts(bool $dry, int $chunk)
    {
        $this->info('Migrating posts');
        $legacy = DB::connection('legacy');

        $query = $legacy->table('forum_posts')->orderBy('post_id');
        $total = $query->count();
        $this->info("Total posts to process: {$total}");

        $bar = $this->output->createProgressBar($total);
        $bar->start();

        // legacy forum_posts uses `post_id` as primary key
        $query->chunkById($chunk, function ($rows) use ($dry, $bar) {
            foreach ($rows as $r) {
                $bar->advance();

                $data = [
                    'id' => $r->post_id,
                    'thread_id' => $r->topic_id,
                    'user_id' => $r->user_id ?? null,
                    'content' => $this->convertLegacyMessage($r->message ?? ''),
                    'is_edited' => isset($r->isupdated) ? (bool)$r->isupdated : false,
                    'edited_at' => $r->updated ?? null,
                ];

                if ($dry) {
                    $this->log('[dry] post: ' . $r->post_id);
                    continue;
                }

                ForumPost::updateOrCreate(['id' => $data['id']], $data);
            }
        }, 'post_id');

        $bar->finish();
        $this->line('');
        $this->info('Posts migrated');
    }

    protected function mapPrivilegeToVisibility($priv)
    {
        // legacy privilege: 0 public, 1 members, 4 staff? adjust mapping conservatively
        if ($priv >= 4) return 'staff';
        if ($priv >= 1) return 'members';
        return 'public';
    }

    protected function normalizeDate($val)
    {
        if (empty($val)) return null;
        $s = trim((string)$val);
        // legacy sometimes contains sentinel invalid dates like -0001-11-30 or zero dates
        if (strpos($s, '-0001') !== false) return null;
        if (strpos($s, '0000-00-00') !== false) return null;
        if (strtotime($s) === false) return null;
        return date('Y-m-d H:i:s', strtotime($s));
    }

    protected function uniqueSlug(string $base, int $id)
    {
        $slug = $base;
        $i = 0;
        while (ForumThread::where('slug', $slug)->where('id', '<>', $id)->exists()) {
            $i++;
            $slug = $base . '-' . $id;
            // if somehow still exists, append counter
            if (ForumThread::where('slug', $slug)->where('id', '<>', $id)->exists()) {
                $slug = $base . '-' . $id . '-' . $i;
            }
        }
        return $slug;
    }

    protected function resolveCategoryId($rootId, $topicId)
    {
        // prefer explicit rootId
        if (!empty($rootId)) {
            // ensure category exists
            if (ForumCategory::where('id', $rootId)->exists()) return $rootId;
        }

        // if this topic itself is a category
        if (ForumCategory::where('id', $topicId)->exists()) return $topicId;

        // fallback: use first available category
        $first = ForumCategory::first();
        if ($first) return $first->id;

        // as last resort, create Uncategorized
        $cat = ForumCategory::create(['name' => 'Uncategorized', 'slug' => 'uncategorized']);
        return $cat->id;
    }

    protected function resolveUserId($userId)
    {
        if (empty($userId)) {
            return 1;
        }

        // check users table in default connection
        if (\DB::table('users')->where('id', $userId)->exists()) {
            return $userId;
        }

        return 1; // fallback system user
    }

    protected function convertLegacyMessage($msg)
    {
        $converter = new BbcodeConverter();
        return $converter->convert($msg);
    }

    protected function generateReport()
    {
        $this->info('Generating migration report');
        $legacy = DB::connection('legacy');

        $legacyCounts = [
            'categories' => $legacy->table('forum_topics')->where('root_id','>',0)->distinct('root_id')->count('root_id'),
            'threads' => $legacy->table('forum_topics')->count(),
            'posts' => $legacy->table('forum_posts')->count(),
        ];

        $newCounts = [
            'categories' => ForumCategory::count(),
            'threads' => ForumThread::count(),
            'posts' => ForumPost::count(),
            'attachments' => \DB::table('forum_attachments')->count(),
        ];

        $this->info('Legacy counts: ' . json_encode($legacyCounts));
        $this->info('New counts: ' . json_encode($newCounts));
        $this->log('Report: legacy=' . json_encode($legacyCounts) . ' new=' . json_encode($newCounts));
    }

    protected function log(string $msg)
    {
        $line = '[' . date('c') . '] ' . $msg . "\n";
        file_put_contents($this->logPath, $line, FILE_APPEND | LOCK_EX);
    }

    protected function migrateGallery(bool $dry, int $chunk)
    {
        $this->info('Migrating gallery (forum_topics_gallery → forum_attachments)');
        $legacy = DB::connection('legacy');

        if (!$legacy->getSchemaBuilder()->hasTable('forum_topics_gallery')) {
            $this->info('No legacy forum_topics_gallery table found, skipping');
            return;
        }

        $query = $legacy->table('forum_topics_gallery')->orderBy('id');
        $total = $query->count();
        $this->info("Total gallery items to process: {$total}");

        $bar = $this->output->createProgressBar($total);
        $bar->start();

        $query->chunkById($chunk, function ($rows) use ($dry, $bar) {
            foreach ($rows as $r) {
                $bar->advance();

                // expected legacy fields: id, name, category (topic id), folder, datum, description
                $topicId = $r->category ?? ($r->topic_id ?? null);
                $fileName = $r->name ?? null;
                if (empty($topicId) || empty($fileName)) {
                    $this->log('Skipping gallery row with missing topic or name: ' . json_encode($r));
                    continue;
                }

                $nid = floor($topicId / 100);
                $relativePath = "files/news/{$nid}/{$topicId}/{$fileName}";
                $publicPath = public_path($relativePath);

                $fileSize = null;
                $mimeType = null;
                $width = null;
                $height = null;

                if (file_exists($publicPath)) {
                    $fileSize = filesize($publicPath);
                    $img = @getimagesize($publicPath);
                    if ($img !== false) {
                        $width = $img[0];
                        $height = $img[1];
                        $mimeType = $img['mime'] ?? null;
                    } else {
                        $finfo = finfo_open(FILEINFO_MIME_TYPE);
                        $mimeType = finfo_file($finfo, $publicPath);
                        finfo_close($finfo);
                    }
                }

                // find legacy first post id for this topic
                $legacy = DB::connection('legacy');
                $firstPostId = $legacy->table('forum_posts')
                    ->where('topic_id', $topicId)
                    ->orderBy('post_date')
                    ->value('post_id');

                // map to new forum_posts id (we preserved ids when migrating)
                $postId = null;
                if ($firstPostId && \App\Models\ForumPost::where('id', $firstPostId)->exists()) {
                    $postId = $firstPostId;
                } else {
                    // fallback: find any post in new DB for thread
                    $post = \App\Models\ForumPost::where('thread_id', $topicId)->orderBy('created_at')->first();
                    if ($post) $postId = $post->id;
                }

                if (empty($postId)) {
                    $this->log('No target post found for gallery item: topic ' . $topicId . ' file ' . $fileName);
                    continue;
                }

                if ($dry) {
                    $this->log("[dry] attach {$relativePath} -> post {$postId}");
                    continue;
                }

                \App\Models\ForumAttachment::create([
                    'post_id' => $postId,
                    'file_path' => $relativePath,
                    'file_size' => $fileSize ?? 0,
                    'mime_type' => $mimeType,
                    'width' => $width,
                    'height' => $height,
                    'created_at' => now(),
                    'updated_at' => now(),
                ]);
            }
        }, 'id');

        $bar->finish();
        $this->line('');
        $this->info('Gallery migrated');
    }
}