<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller;
use App\Http\Requests\StoreEventRequest;
use App\Http\Requests\UpdateEventRequest;
use App\Http\Resources\EventResource;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Http\Resources\Json\AnonymousResourceCollection;

class EventController extends Controller
{
    /**
     * GET /api/events
     * Cursor-based pagination by date. Supports ?since=ISO for delta sync.
     */
    public function index(Request $request): AnonymousResourceCollection
    {
        $query = $request->user()->events()->orderBy('date');

        // Delta sync: only events updated since a given timestamp
        if ($request->has('since')) {
            $since = $request->date('since');
            $query->where('updated_at', '>', $since);
        }

        // Cursor-based pagination (default 50, max 200)
        $limit = min((int) $request->input('limit', 50), 200);

        return EventResource::collection(
            $query->cursorPaginate($limit)
        );
    }

    /**
     * POST /api/events
     */
    public function store(StoreEventRequest $request): JsonResponse
    {
        $event = $request->user()->events()->create([
            'client_id' => $request->validated('id'),
            'title' => $request->validated('title'),
            'date' => $request->validated('date'),
            'emotion' => $request->validated('emotion'),
            'custom_color' => $request->validated('customColor'),
            'gradient_preset' => $request->validated('gradientPreset'),
            'image' => $request->validated('image'),
            'note' => $request->validated('note'),
        ]);

        return (new EventResource($event))
            ->response()
            ->setStatusCode(201);
    }

    /**
     * GET /api/events/{clientId}
     */
    public function show(Request $request, string $clientId): EventResource
    {
        $event = $request->user()->events()
            ->where('client_id', $clientId)
            ->firstOrFail();

        return new EventResource($event);
    }

    /**
     * PUT /api/events/{clientId}
     */
    public function update(UpdateEventRequest $request, string $clientId): EventResource
    {
        $event = $request->user()->events()
            ->where('client_id', $clientId)
            ->firstOrFail();

        $data = [];
        $validated = $request->validated();

        if (isset($validated['title'])) {
            $data['title'] = $validated['title'];
        }
        if (isset($validated['date'])) {
            $data['date'] = $validated['date'];
        }
        if (isset($validated['emotion'])) {
            $data['emotion'] = $validated['emotion'];
        }
        if (array_key_exists('customColor', $validated)) {
            $data['custom_color'] = $validated['customColor'];
        }
        if (array_key_exists('gradientPreset', $validated)) {
            $data['gradient_preset'] = $validated['gradientPreset'];
        }
        if (array_key_exists('image', $validated)) {
            $data['image'] = $validated['image'];
        }
        if (array_key_exists('note', $validated)) {
            $data['note'] = $validated['note'];
        }

        $event->update($data);

        return new EventResource($event->fresh());
    }

    /**
     * DELETE /api/events/{clientId}
     */
    public function destroy(Request $request, string $clientId): JsonResponse
    {
        $event = $request->user()->events()
            ->where('client_id', $clientId)
            ->firstOrFail();

        $event->delete();

        return response()->json(null, 204);
    }

    /**
     * POST /api/events/sync
     * Batch sync: process multiple mutations in one request.
     */
    public function sync(Request $request): JsonResponse
    {
        $request->validate([
            'mutations' => ['required', 'array', 'max:100'],
            'mutations.*.action' => ['required', 'in:create,update,delete'],
            'mutations.*.eventId' => ['required', 'uuid'],
            'mutations.*.payload' => ['nullable', 'array'],
        ]);

        $user = $request->user();
        $results = [];

        foreach ($request->input('mutations') as $mutation) {
            $action = $mutation['action'];
            $clientId = $mutation['eventId'];
            $payload = $mutation['payload'] ?? [];

            try {
                if ($action === 'create') {
                    $event = $user->events()->where('client_id', $clientId)->first();
                    if (! $event) {
                        $event = $user->events()->create([
                            'client_id' => $clientId,
                            'title' => $payload['title'] ?? 'Untitled',
                            'date' => $payload['date'] ?? now()->format('Y-m-d'),
                            'emotion' => $payload['emotion'] ?? 0,
                            'custom_color' => $payload['customColor'] ?? null,
                            'gradient_preset' => $payload['gradientPreset'] ?? null,
                            'image' => $payload['image'] ?? null,
                            'note' => $payload['note'] ?? null,
                        ]);
                    }
                    $results[] = ['eventId' => $clientId, 'status' => 'ok'];
                } elseif ($action === 'update') {
                    $event = $user->events()->where('client_id', $clientId)->first();
                    if ($event) {
                        $data = [];
                        if (isset($payload['title'])) {
                            $data['title'] = $payload['title'];
                        }
                        if (isset($payload['date'])) {
                            $data['date'] = $payload['date'];
                        }
                        if (isset($payload['emotion'])) {
                            $data['emotion'] = $payload['emotion'];
                        }
                        if (array_key_exists('customColor', $payload)) {
                            $data['custom_color'] = $payload['customColor'];
                        }
                        if (array_key_exists('gradientPreset', $payload)) {
                            $data['gradient_preset'] = $payload['gradientPreset'];
                        }
                        if (array_key_exists('image', $payload)) {
                            $data['image'] = $payload['image'];
                        }
                        if (array_key_exists('note', $payload)) {
                            $data['note'] = $payload['note'];
                        }
                        $event->update($data);
                    }
                    $results[] = ['eventId' => $clientId, 'status' => 'ok'];
                } elseif ($action === 'delete') {
                    $user->events()->where('client_id', $clientId)->delete();
                    $results[] = ['eventId' => $clientId, 'status' => 'ok'];
                }
            } catch (\Throwable $e) {
                $results[] = ['eventId' => $clientId, 'status' => 'error', 'message' => $e->getMessage()];
            }
        }

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