<?php

namespace App\Http\Controllers;

use App\Models\DirectMessage;
use App\Models\DirectThread;
use App\Models\Story;
use Illuminate\Http\JsonResponse;

class ThreadController extends Controller
{
    /**
     * Instagram's own story permalinks embed both the poster's username and
     * the story item's numeric pk: instagram.com/stories/{username}/{pk}.
     * That pk is the same id our story scraper stores.
     */
    private function parseStorySharePk(?string $url): ?array
    {
        if (! $url || ! preg_match('#/stories/([^/?]+)/(\d+)#', $url, $matches)) {
            return null;
        }

        return ['username' => $matches[1], 'item_id' => $matches[2]];
    }

    public function index(): JsonResponse
    {
        $threads = DirectThread::query()
            ->with(['messages' => fn ($query) => $query->orderByDesc('timestamp')->limit(1)])
            ->orderByDesc('last_activity_at')
            ->get()
            ->map(function (DirectThread $thread) {
                $last = $thread->messages->first();

                return [
                    'thread_id' => $thread->thread_id,
                    'thread_title' => $thread->thread_title,
                    'is_group' => $thread->is_group,
                    'participants' => $thread->participants,
                    'last_activity_at' => $thread->last_activity_at,
                    'muted' => $thread->muted,
                    'last_message' => $last ? [
                        'username' => $last->username,
                        'text' => $last->text,
                        'item_type' => $last->item_type,
                        'timestamp' => $last->timestamp,
                    ] : null,
                ];
            });

        return response()->json($threads);
    }

    public function show(string $threadId): JsonResponse
    {
        $thread = DirectThread::findOrFail($threadId);

        $messages = $thread->messages()->orderBy('timestamp')->get();

        // Batch-check which story shares actually still exist in our local
        // `stories` table, so we only need one query for the whole thread
        // rather than one per message.
        $storyPks = $messages
            ->map(fn (DirectMessage $m) => $this->parseStorySharePk($m->shared_url)['item_id'] ?? null)
            ->filter()
            ->unique()
            ->values();

        $existingStoryIds = Story::whereIn('id', $storyPks)->pluck('id')->all();

        $messages = $messages->map(function (DirectMessage $message) use ($existingStoryIds) {
            $storyShare = $this->parseStorySharePk($message->shared_url);

            return [
                'id' => $message->id,
                'user_id' => $message->user_id,
                'username' => $message->username,
                'full_name' => $message->full_name,
                'item_type' => $message->item_type,
                'text' => $message->text,
                'timestamp' => $message->timestamp,
                'shared_url' => $message->shared_url,
                'shared_preview_image' => $message->shared_preview_image,
                'shared_title' => $message->shared_title,
                'shared_caption' => $message->shared_caption,
                'attachments' => $message->attachments,
                'reactions' => $message->reactions,
                'replied_to_id' => $message->replied_to_id,
                'replied_to_text' => $message->replied_to_text,
                'story_share' => $storyShare ? [
                    'username' => $storyShare['username'],
                    'item_id' => $storyShare['item_id'],
                    'exists_locally' => in_array($storyShare['item_id'], $existingStoryIds, true),
                ] : null,
            ];
        });

        return response()->json([
            'thread_id' => $thread->thread_id,
            'thread_title' => $thread->thread_title,
            'is_group' => $thread->is_group,
            'participants' => $thread->participants,
            'muted' => $thread->muted,
            'messages' => $messages,
        ]);
    }
}