<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller;
use App\Models\Conversation;
use App\Models\Message;
use App\Models\User;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\DB;

class MessageApiController extends Controller
{
    // GET /api/messages — conversations list
    public function conversations()
    {
        $user = Auth::user();

        $convs = $user->conversations()
            ->with(['participants', 'lastMessage.user'])
            ->orderByDesc('conversations.updated_at')
            ->limit(50)
            ->get()
            ->map(function ($conv) use ($user) {
                $other  = $conv->participants->firstWhere('id', '!=', $user->id);
                $last   = $conv->lastMessage;
                $unread = $conv->unreadCountFor($user->id);

                $preview = null;
                if ($last) {
                    if (str_starts_with($last->body, 'IMAGE::'))       $preview = '📷 Fotoğraf';
                    elseif (str_starts_with($last->body, 'GIF::'))     $preview = '🎞 GIF';
                    elseif (str_starts_with($last->body, 'ANIMESHARE::')) {
                        try { $sd = json_decode(substr($last->body, 12), true); $preview = '🎬 ' . ($sd['title'] ?? 'Anime'); } catch (\Throwable) {}
                    } else {
                        $isMine  = $last->user_id === $user->id;
                        $preview = ($isMine ? 'Sen: ' : '') . \Illuminate\Support\Str::limit($last->body, 60);
                    }
                }

                return [
                    'id'           => $conv->id,
                    'other_user'   => $other ? [
                        'id'       => $other->id,
                        'name'     => $other->name,
                        'username' => $other->username,
                        'avatar'   => $other->avatar ? \App\Support\MediaUrl::fromStoragePath($other->avatar) : null,
                    ] : null,
                    'last_message' => $last ? [
                        'body'       => $preview ?? '',
                        'user_id'    => $last->user_id,
                        'created_at' => $last->created_at?->toISOString(),
                    ] : null,
                    'unread_count' => $unread,
                    'updated_at'   => $conv->updated_at?->toISOString(),
                ];
            });

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

    // GET /api/messages/{conversation} — messages in a conversation
    public function show(Conversation $conversation)
    {
        $user = Auth::user();

        abort_unless($conversation->participants()->where('user_id', $user->id)->exists(), 403);

        $other = $conversation->participants()->where('user_id', '!=', $user->id)->first();

        $messages = $conversation->messages()
            ->with('user')
            ->orderBy('created_at')
            ->get()
            ->map(fn($m) => [
                'id'         => $m->id,
                'user_id'    => $m->user_id,
                'body'       => $m->body,
                'created_at' => $m->created_at?->toISOString(),
                'author'     => [
                    'id'     => $m->user?->id,
                    'name'   => $m->user?->name,
                    'avatar' => $m->user?->avatar ? \App\Support\MediaUrl::fromStoragePath($m->user->avatar) : null,
                ],
            ]);

        // Mark as read
        $conversation->participants()->updateExistingPivot($user->id, ['last_read_at' => now()]);

        return response()->json([
            'messages'   => $messages,
            'other_user' => $other ? [
                'id'       => $other->id,
                'name'     => $other->name,
                'username' => $other->username,
                'avatar'   => $other->avatar ? \App\Support\MediaUrl::fromStoragePath($other->avatar) : null,
            ] : null,
        ]);
    }

    // POST /api/messages/{conversation} — send a message
    public function send(Request $request, Conversation $conversation)
    {
        $user = Auth::user();

        abort_unless($conversation->participants()->where('user_id', $user->id)->exists(), 403);

        $request->validate(['body' => 'required|string|max:5000']);

        $message = Message::create([
            'conversation_id' => $conversation->id,
            'user_id'         => $user->id,
            'body'            => $request->body,
        ]);

        $conversation->touch();
        $conversation->participants()->updateExistingPivot($user->id, ['last_read_at' => now()]);

        return response()->json([
            'id'         => $message->id,
            'user_id'    => $user->id,
            'body'       => $message->body,
            'created_at' => $message->created_at->toISOString(),
            'author'     => [
                'id'     => $user->id,
                'name'   => $user->name,
                'avatar' => $user->avatar ? \App\Support\MediaUrl::fromStoragePath($user->avatar) : null,
            ],
        ]);
    }

    // POST /api/messages/start/{user} — start or open conversation
    public function startConversation(User $user)
    {
        $me = Auth::user();

        if ($me->id === $user->id) abort(422, 'Kendinize mesaj gönderemezsiniz.');

        $conv = Conversation::whereHas('participants', fn($q) => $q->where('user_id', $me->id))
            ->whereHas('participants', fn($q) => $q->where('user_id', $user->id))
            ->first();

        if (!$conv) {
            $conv = DB::transaction(function () use ($me, $user) {
                $c = Conversation::create();
                $c->participants()->attach([$me->id, $user->id]);
                return $c;
            });
        }

        return response()->json(['conversation_id' => $conv->id]);
    }

    // GET /api/messages/{conv}/poll?after={id} — poll for new messages (mobile)
    public function poll(Request $request, Conversation $conversation)
    {
        $user = Auth::user();
        abort_unless($conversation->participants()->where('user_id', $user->id)->exists(), 403);

        $after = (int) $request->query('after', 0);

        $messages = $conversation->messages()
            ->with('user')
            ->where('id', '>', $after)
            ->orderBy('created_at')
            ->get()
            ->map(fn($m) => [
                'id'         => $m->id,
                'user_id'    => $m->user_id,
                'body'       => $m->body,
                'created_at' => $m->created_at?->toISOString(),
                'author'     => [
                    'id'     => $m->user?->id,
                    'name'   => $m->user?->name,
                    'avatar' => $m->user?->avatar ? \App\Support\MediaUrl::fromStoragePath($m->user->avatar) : null,
                ],
            ]);

        $conversation->participants()->updateExistingPivot($user->id, ['last_read_at' => now()]);

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