<?php

namespace App\Http\Controllers;

use App\Models\Task;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Validation\Rule;

class TaskController extends Controller {
    public function index(Request $r) {
        $tasks = $r->user()->tasks()
            ->with(['project:id,name,color', 'tags:id,name,color'])
            ->orderBy('done')
            ->orderByRaw("FIELD(priority,'high','med','low')")
            ->orderBy('created_at')
            ->get();
        return response()->json($tasks);
    }

    public function pending(Request $r): JsonResponse {
        $tasks = $r->user()->tasks()
            ->active()
            ->with('project:id,name,color')
            ->orderByRaw("FIELD(priority,'high','med','low')")
            ->orderBy('created_at')
            ->limit(20)
            ->get();
        return response()->json($tasks->map(fn ($t) => [
            'id'           => $t->id,
            'title'        => $t->title,
            'priority'     => $t->priority,
            'project'      => $t->project?->name,
            'next_due_in'  => $t->next_due_in,
            'estimate_min' => $t->estimate_min,
        ]));
    }

    public function store(Request $r): JsonResponse {
        $data = $r->validate([
            'title'        => 'required|string|max:120',
            'description'  => 'nullable|string',
            'priority'     => 'nullable|in:low,med,high',
            'estimate_min' => 'nullable|integer|min:1|max:9999',
            'deadline'     => 'nullable|date',
            'project_id'   => 'nullable|integer|exists:projects,id',
            'recurrence'   => 'nullable|in:daily,weekly,monthly',
            'tags'         => 'nullable|array',
            'tags.*'       => 'string|max:30',
        ]);
        $task = $r->user()->tasks()->create([
            'title'        => $data['title'],
            'description'  => $data['description'] ?? null,
            'priority'     => $data['priority'] ?? 'med',
            'estimate_min' => $data['estimate_min'] ?? null,
            'deadline'     => $data['deadline']   ?? null,
            'project_id'   => $data['project_id'] ?? null,
            'recurrence'   => $data['recurrence'] ?? null,
        ]);
        if (! empty($data['tags'])) {
            $this->syncTags($task, $data['tags']);
        }
        return response()->json($task->load('project', 'tags'), 201);
    }

    public function update(Request $r, Task $task): JsonResponse {
        abort_unless($task->user_id === $r->user()->id, 403);
        $data = $r->validate([
            'title'        => 'sometimes|required|string|max:120',
            'description'  => 'nullable|string',
            'priority'     => 'nullable|in:low,med,high',
            'estimate_min' => 'nullable|integer|min:1|max:9999',
            'deadline'     => 'nullable|date',
            'project_id'   => 'nullable|integer|exists:projects,id',
            'recurrence'   => 'nullable|in:daily,weekly,monthly',
            'tags'         => 'nullable|array',
        ]);
        $task->update(array_intersect_key($data, array_flip([
            'title', 'description', 'priority', 'estimate_min',
            'deadline', 'project_id', 'recurrence',
        ])));
        if (array_key_exists('tags', $data)) {
            $this->syncTags($task, $data['tags']);
        }
        return response()->json($task->load('project', 'tags'));
    }

    public function done(Request $r, Task $task): JsonResponse {
        abort_unless($task->user_id === $r->user()->id, 403);
        $task->update(['done' => true, 'done_at' => now()]);
        // Si la tarea es recurrente, generamos la siguiente
        if ($task->recurrence) {
            $next = $task->replicate(['done', 'done_at', 'snooze_until']);
            $next->done = false;
            $next->done_at = null;
            $next->snooze_until = null;
            $next->deadline = match ($task->recurrence) {
                'daily'   => $task->deadline?->addDay()  ?? now()->addDay(),
                'weekly'  => $task->deadline?->addWeek() ?? now()->addWeek(),
                'monthly' => $task->deadline?->addMonth() ?? now()->addMonth(),
                default   => null,
            };
            $next->save();
        }
        return response()->json(['ok' => true, 'id' => $task->id]);
    }

    public function snooze(Request $r, Task $task): JsonResponse {
        abort_unless($task->user_id === $r->user()->id, 403);
        $minutes = (int) $r->input('minutes', 5);
        $minutes = max(1, min(720, $minutes));
        $task->update(['snooze_until' => now()->addMinutes($minutes)]);
        return response()->json(['ok' => true, 'id' => $task->id, 'minutes' => $minutes]);
    }

    public function destroy(Request $r, Task $task): JsonResponse {
        abort_unless($task->user_id === $r->user()->id, 403);
        $task->delete();
        return response()->json(['ok' => true]);
    }

    public function restore(Request $r, Task $task): JsonResponse {
        abort_unless($task->user_id === $r->user()->id, 403);
        $task->update(['done' => false, 'done_at' => null, 'snooze_until' => null]);
        return response()->json($task);
    }

    /** Estadísticas rápidas para el dashboard */
    public function stats(Request $r): JsonResponse {
        $userId = $r->user()->id;
        $today = now()->startOfDay();
        return response()->json([
            'pending'   => Task::forUser($userId)->active()->count(),
            'today'     => Task::forUser($userId)->active()
                            ->where('created_at', '>=', $today)->count(),
            'done_today'=> Task::forUser($userId)->where('done', true)
                            ->where('done_at', '>=', $today)->count(),
            'overdue'   => Task::forUser($userId)->active()
                            ->where('deadline', '<', now())->count(),
            'total_done'=> Task::forUser($userId)->where('done', true)->count(),
        ]);
    }

    private function syncTags(Task $task, array $tagNames): void {
        $userId = $task->user_id;
        $ids = [];
        foreach ($tagNames as $name) {
            $tag = \App\Models\Tag::firstOrCreate(
                ['user_id' => $userId, 'name' => $name],
                ['color' => '#a3a3a3']
            );
            $ids[] = $tag->id;
        }
        $task->tags()->sync($ids);
    }
}