<?php
/**
 * Contrôleur des tâches
 */

declare(strict_types=1);

class TaskController extends Controller
{
    /**
     * GET /tasks
     * Liste les tâches avec filtres optionnels
     * ?project_id=X - filtrer par projet
     * ?status_id=X - filtrer par statut
     * ?tag_id=X - filtrer par tag
     * ?date_start=YYYY-MM-DD - tâches commençant après
     * ?date_end=YYYY-MM-DD - tâches finissant avant
     */
    public function index(): void
    {
        $this->requireAuth();

        $db = Database::getInstance();

        $where = ['t.user_id = :user_id'];
        $params = ['user_id' => $this->getUserId()];

        // Filtre par projet
        $projectId = $this->request->get('project_id');
        if ($projectId !== null) {
            $where[] = 't.project_id = :project_id';
            $params['project_id'] = (int) $projectId;
        }

        // Filtre par statut
        $statusId = $this->request->get('status_id');
        if ($statusId !== null) {
            $where[] = 't.status_id = :status_id';
            $params['status_id'] = (int) $statusId;
        }

        // Filtre par date de début
        $dateStart = $this->request->get('date_start');
        if ($dateStart !== null) {
            $where[] = 't.date_start >= :date_start';
            $params['date_start'] = $dateStart;
        }

        // Filtre par date de fin
        $dateEnd = $this->request->get('date_end');
        if ($dateEnd !== null) {
            $where[] = 't.date_end <= :date_end';
            $params['date_end'] = $dateEnd;
        }

        $sql = '
            SELECT t.*,
                   p.name as project_name,
                   s.name as status_name,
                   s.color as status_color,
                   GROUP_CONCAT(tg.id) as tag_ids,
                   GROUP_CONCAT(tg.name) as tag_names,
                   GROUP_CONCAT(tg.color) as tag_colors
            FROM tasks t
            LEFT JOIN projects p ON t.project_id = p.id
            LEFT JOIN statuses s ON t.status_id = s.id
            LEFT JOIN task_tags tt ON t.id = tt.task_id
            LEFT JOIN tags tg ON tt.tag_id = tg.id
            WHERE ' . implode(' AND ', $where) . '
            GROUP BY t.id
            ORDER BY t.position ASC, t.priority DESC, t.created_at DESC
        ';

        $stmt = $db->prepare($sql);
        $stmt->execute($params);
        $tasks = $stmt->fetchAll();

        // Filtre par tag (après GROUP BY)
        $tagId = $this->request->get('tag_id');

        // Parser les tags
        foreach ($tasks as &$task) {
            $task['tags'] = $this->parseTags($task);
            unset($task['tag_ids'], $task['tag_names'], $task['tag_colors']);
        }

        // Appliquer filtre tag si nécessaire
        if ($tagId !== null) {
            $tagId = (int) $tagId;
            $tasks = array_filter($tasks, function ($task) use ($tagId) {
                foreach ($task['tags'] as $tag) {
                    if ($tag['id'] === $tagId) {
                        return true;
                    }
                }
                return false;
            });
            $tasks = array_values($tasks);
        }

        Response::success($tasks);
    }

    /**
     * GET /tasks/{id}
     */
    public function show(): void
    {
        $this->requireAuth();

        $id = (int) $this->request->getParam('id');
        $task = $this->findOrFail($id);

        $task['tags'] = $this->getTaskTags($id);

        Response::success($task);
    }

    /**
     * POST /tasks
     */
    public function store(): void
    {
        $this->requireAuth();

        $data = $this->validate([
            'project_id' => 'required|int',
            'status_id' => 'required|int',
            'title' => 'required|min:1|max:255',
            'description' => 'max:65535',
            'priority' => 'int',
            'date_start' => 'max:10',
            'date_end' => 'max:10',
            'time_estimated' => 'int',
            'time_spent' => 'int',
            'billing' => 'numeric',
            'position' => 'int',
        ]);

        // Vérifier que le projet appartient à l'utilisateur
        $this->verifyProject((int) $data['project_id']);

        // Vérifier que le statut appartient à l'utilisateur
        $this->verifyStatus((int) $data['status_id']);

        $db = Database::getInstance();

        $stmt = $db->prepare('
            INSERT INTO tasks (user_id, project_id, status_id, title, description, priority,
                               date_start, date_end, time_estimated, time_spent, billing, position)
            VALUES (:user_id, :project_id, :status_id, :title, :description, :priority,
                    :date_start, :date_end, :time_estimated, :time_spent, :billing, :position)
        ');

        $stmt->execute([
            'user_id' => $this->getUserId(),
            'project_id' => $data['project_id'],
            'status_id' => $data['status_id'],
            'title' => $data['title'],
            'description' => $data['description'] ?? null,
            'priority' => $data['priority'] ?? 5,
            'date_start' => $data['date_start'] ?: null,
            'date_end' => $data['date_end'] ?: null,
            'time_estimated' => $data['time_estimated'] ?? 0,
            'time_spent' => $data['time_spent'] ?? 0,
            'billing' => $data['billing'] ?? 0,
            'position' => $data['position'] ?? 0,
        ]);

        $taskId = (int) $db->lastInsertId();

        // Gérer les tags si fournis
        $tags = $this->request->get('tags');
        if (is_array($tags)) {
            $this->syncTags($taskId, $tags);
        }

        $task = $this->findOrFail($taskId);
        $task['tags'] = $this->getTaskTags($taskId);

        Response::success($task, 'Tâche créée', 201);
    }

    /**
     * PUT /tasks/{id}
     */
    public function update(): void
    {
        $this->requireAuth();

        $id = (int) $this->request->getParam('id');
        $this->findOrFail($id);

        $data = $this->validate([
            'project_id' => 'int',
            'status_id' => 'int',
            'title' => 'min:1|max:255',
            'description' => 'max:65535',
            'priority' => 'int',
            'date_start' => 'max:10',
            'date_end' => 'max:10',
            'time_estimated' => 'int',
            'time_spent' => 'int',
            'billing' => 'numeric',
            'position' => 'int',
        ]);

        if (!empty($data['project_id'])) {
            $this->verifyProject((int) $data['project_id']);
        }

        if (!empty($data['status_id'])) {
            $this->verifyStatus((int) $data['status_id']);
        }

        $db = Database::getInstance();

        $fields = [];
        $params = ['id' => $id];

        $allowedFields = [
            'project_id', 'status_id', 'title', 'description', 'priority',
            'date_start', 'date_end', 'time_estimated', 'time_spent', 'billing', 'position'
        ];

        foreach ($allowedFields as $field) {
            if (array_key_exists($field, $data)) {
                $fields[] = "{$field} = :{$field}";
                $value = $data[$field];
                // Convertir les chaînes vides en null pour les dates
                if (in_array($field, ['date_start', 'date_end']) && $value === '') {
                    $value = null;
                }
                $params[$field] = $value;
            }
        }

        if (!empty($fields)) {
            $sql = 'UPDATE tasks SET ' . implode(', ', $fields) . ' WHERE id = :id';
            $stmt = $db->prepare($sql);
            $stmt->execute($params);
        }

        // Gérer les tags si fournis
        $tags = $this->request->get('tags');
        if (is_array($tags)) {
            $this->syncTags($id, $tags);
        }

        $task = $this->findOrFail($id);
        $task['tags'] = $this->getTaskTags($id);

        Response::success($task, 'Tâche mise à jour');
    }

    /**
     * DELETE /tasks/{id}
     */
    public function destroy(): void
    {
        $this->requireAuth();

        $id = (int) $this->request->getParam('id');
        $this->findOrFail($id);

        $db = Database::getInstance();

        $stmt = $db->prepare('DELETE FROM tasks WHERE id = :id');
        $stmt->execute(['id' => $id]);

        Response::success(null, 'Tâche supprimée');
    }

    /**
     * Trouver une tâche ou retourner 404
     */
    private function findOrFail(int $id): array
    {
        $db = Database::getInstance();

        $stmt = $db->prepare('
            SELECT t.*, p.name as project_name, s.name as status_name, s.color as status_color
            FROM tasks t
            LEFT JOIN projects p ON t.project_id = p.id
            LEFT JOIN statuses s ON t.status_id = s.id
            WHERE t.id = :id AND t.user_id = :user_id
        ');

        $stmt->execute([
            'id' => $id,
            'user_id' => $this->getUserId(),
        ]);

        $task = $stmt->fetch();

        if (!$task) {
            Response::notFound('Tâche non trouvée');
        }

        return $task;
    }

    /**
     * Vérifier qu'un projet appartient à l'utilisateur
     */
    private function verifyProject(int $projectId): void
    {
        $db = Database::getInstance();

        $stmt = $db->prepare('SELECT id FROM projects WHERE id = :id AND user_id = :user_id');
        $stmt->execute(['id' => $projectId, 'user_id' => $this->getUserId()]);

        if (!$stmt->fetch()) {
            Response::error('Projet invalide', 422);
        }
    }

    /**
     * Vérifier qu'un statut appartient à l'utilisateur
     */
    private function verifyStatus(int $statusId): void
    {
        $db = Database::getInstance();

        $stmt = $db->prepare('SELECT id FROM statuses WHERE id = :id AND user_id = :user_id');
        $stmt->execute(['id' => $statusId, 'user_id' => $this->getUserId()]);

        if (!$stmt->fetch()) {
            Response::error('Statut invalide', 422);
        }
    }

    /**
     * Parser les tags depuis le GROUP_CONCAT
     */
    private function parseTags(array $task): array
    {
        $tags = [];
        if (!empty($task['tag_ids'])) {
            $ids = explode(',', $task['tag_ids']);
            $names = explode(',', $task['tag_names']);
            $colors = explode(',', $task['tag_colors']);
            foreach ($ids as $i => $tagId) {
                $tags[] = [
                    'id' => (int) $tagId,
                    'name' => $names[$i] ?? '',
                    'color' => $colors[$i] ?? '#3B82F6',
                ];
            }
        }
        return $tags;
    }

    /**
     * Récupérer les tags d'une tâche
     */
    private function getTaskTags(int $taskId): array
    {
        $db = Database::getInstance();

        $stmt = $db->prepare('
            SELECT t.id, t.name, t.color
            FROM tags t
            JOIN task_tags tt ON t.id = tt.tag_id
            WHERE tt.task_id = :task_id
        ');

        $stmt->execute(['task_id' => $taskId]);

        return $stmt->fetchAll();
    }

    /**
     * Synchroniser les tags d'une tâche
     */
    private function syncTags(int $taskId, array $tagIds): void
    {
        $db = Database::getInstance();

        $stmt = $db->prepare('DELETE FROM task_tags WHERE task_id = :task_id');
        $stmt->execute(['task_id' => $taskId]);

        if (!empty($tagIds)) {
            $stmt = $db->prepare('
                INSERT INTO task_tags (task_id, tag_id)
                SELECT :task_id, id FROM tags
                WHERE id = :tag_id AND user_id = :user_id
            ');

            foreach ($tagIds as $tagId) {
                $stmt->execute([
                    'task_id' => $taskId,
                    'tag_id' => (int) $tagId,
                    'user_id' => $this->getUserId(),
                ]);
            }
        }
    }
}