<?php

namespace App\Http\Controllers;

use App\Models\Video;
use App\Services\VideoMergeService;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;

class VideoMergeController extends Controller
{
    public function __construct(private VideoMergeService $merger) {}

    /**
     * List the current user's other music videos that $target can be merged with.
     */
    public function candidates(Request $request, Video $target)
    {
        $this->authorizeOwner($target);
        if ($target->type !== 'music') {
            return response()->json(['error' => 'Only music videos can be merged.'], 422);
        }

        $q = trim((string) $request->query('q', ''));
        $query = Video::where('user_id', Auth::id())
            ->where('type', 'music')
            ->where('id', '!=', $target->id)
            ->orderByDesc('created_at');
        if ($q !== '') {
            $query->where('title', 'like', '%' . $q . '%');
        }
        $items = $query->limit(30)->get(['id', 'title', 'thumbnail', 'created_at'])->map(function ($v) {
            return [
                'id'        => $v->getRouteKey(),
                'title'     => $v->title,
                'thumbnail' => $v->thumbnail_url,
                'created'   => $v->created_at?->diffForHumans(),
            ];
        });

        return response()->json(['items' => $items]);
    }

    public function preview(Video $target, Video $source)
    {
        $this->authorizeOwner($target);
        $this->authorizeOwner($source);
        if ($target->type !== 'music' || $source->type !== 'music') {
            return response()->json(['error' => 'Only music videos can be merged.'], 422);
        }
        if ($target->id === $source->id) {
            return response()->json(['error' => 'Cannot merge a video with itself.'], 422);
        }

        return response()->json([
            'source' => [
                'id'    => $source->getRouteKey(),
                'title' => $source->title,
                'thumb' => $source->thumbnail_url,
            ],
            'target' => [
                'id'    => $target->getRouteKey(),
                'title' => $target->title,
                'thumb' => $target->thumbnail_url,
            ],
            'counts' => $this->merger->preview($source, $target),
        ]);
    }

    public function merge(Request $request, Video $target, Video $source)
    {
        $this->authorizeOwner($target);
        $this->authorizeOwner($source);

        try {
            $this->merger->merge($source, $target);
        } catch (\Throwable $e) {
            \Log::error('Video merge failed', [
                'source' => $source->id,
                'target' => $target->id,
                'err'    => $e->getMessage(),
            ]);
            return response()->json(['error' => 'Merge failed: ' . $e->getMessage()], 500);
        }

        return response()->json([
            'ok'       => true,
            'redirect' => route('videos.show', $target),
        ]);
    }

    private function authorizeOwner(Video $video): void
    {
        $user = Auth::user();
        if (!$user) abort(401);
        if ($user->id !== $video->user_id && !$user->isSuperAdmin()) abort(403);
    }
}