<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller;
use App\Http\Resources\ProgramResource;
use App\Models\Program;
use App\Models\WorkoutSession;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;

class ProgramController extends Controller
{
    public function index(): JsonResponse
    {
        $programs = Auth::user()->programs()->withCount('workouts')->latest()->paginate(10);

        return response()->json([
            'data' => ProgramResource::collection($programs->items()),
            'meta' => [
                'current_page' => $programs->currentPage(),
                'last_page' => $programs->lastPage(),
                'per_page' => $programs->perPage(),
                'total' => $programs->total(),
            ],
        ]);
    }

    public function store(Request $request): JsonResponse
    {
        $data = $request->validate([
            'title' => ['required', 'string', 'max:255'],
            'description' => ['nullable', 'string'],
            'weeks' => ['required', 'integer', 'min:1', 'max:52'],
        ]);

        $program = Auth::user()->programs()->create($data);

        return response()->json(['program' => new ProgramResource($program)], 201);
    }

    public function show(Program $program): JsonResponse
    {
        $this->authorizeProgram($program);
        $program->load('workouts');

        $completedWorkoutIds = WorkoutSession::query()
            ->where('user_id', Auth::id())
            ->whereIn('workout_id', $program->workouts->pluck('id'))
            ->whereNotNull('completed_at')
            ->pluck('workout_id')
            ->unique();

        $totalWorkouts = $program->workouts->count();
        $completedCount = $completedWorkoutIds->count();
        $progressPct = $totalWorkouts > 0 ? (int) round(($completedCount / $totalWorkouts) * 100) : 0;

        return response()->json([
            'program' => new ProgramResource($program),
            'completed_workout_ids' => $completedWorkoutIds->values(),
            'progress_pct' => $progressPct,
            'completed_count' => $completedCount,
            'total_workouts' => $totalWorkouts,
        ]);
    }

    public function destroy(Program $program): JsonResponse
    {
        $this->authorizeProgram($program);
        $program->delete();

        return response()->json(['message' => 'Program deleted']);
    }

    public function addWorkout(Request $request, Program $program): JsonResponse
    {
        $this->authorizeProgram($program);
        $data = $request->validate([
            'title' => ['required', 'string', 'max:255'],
            'week_number' => ['required', 'integer', 'min:1', 'max:'.$program->weeks],
            'day_number' => ['required', 'integer', 'min:1', 'max:14'],
            'estimated_minutes' => ['nullable', 'integer', 'min:1', 'max:600'],
        ]);

        $workout = $program->workouts()->create([
            'user_id' => Auth::id(),
            'title' => $data['title'],
            'estimated_minutes' => $data['estimated_minutes'] ?? null,
            'week_number' => $data['week_number'],
            'day_number' => $data['day_number'],
        ]);

        return response()->json(['workout_id' => $workout->id, 'message' => 'Workout added to program'], 201);
    }

    protected function authorizeProgram(Program $program): void
    {
        if ($program->user_id !== Auth::id()) {
            abort(403);
        }
    }
}