<?php
/**
 * Contrôleur des projets
 */

declare(strict_types=1);

class ProjectController extends Controller
{
    /**
     * GET /projects
     * Liste tous les projets de l'utilisateur (arborescence)
     */
    public function index(): void
    {
        $this->requireAuth();

        $db = Database::getInstance();

        // Récupérer tous les projets de l'utilisateur
        $stmt = $db->prepare('
            SELECT p.*,
                   GROUP_CONCAT(t.id) as tag_ids,
                   GROUP_CONCAT(t.name) as tag_names
            FROM projects p
            LEFT JOIN project_tags pt ON p.id = pt.project_id
            LEFT JOIN tags t ON pt.tag_id = t.id
            WHERE p.user_id = :user_id
            GROUP BY p.id
            ORDER BY p.parent_id ASC, p.position ASC, p.name ASC
        ');

        $stmt->execute(['user_id' => $this->getUserId()]);
        $projects = $stmt->fetchAll();

        // Construire l'arborescence
        $tree = $this->buildTree($projects);

        Response::success($tree);
    }

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

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

        // Récupérer les tags
        $project['tags'] = $this->getProjectTags($id);

        // Récupérer les sous-projets
        $project['children'] = $this->getChildren($id);

        Response::success($project);
    }

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

        $data = $this->validate([
            'name' => 'required|min:1|max:100',
            'description' => 'max:65535',
            'parent_id' => 'int',
            'position' => 'int',
        ]);

        // Vérifier que le parent appartient à l'utilisateur
        if (!empty($data['parent_id'])) {
            $this->findOrFail((int) $data['parent_id']);
        }

        $db = Database::getInstance();

        $stmt = $db->prepare('
            INSERT INTO projects (user_id, parent_id, name, description, position)
            VALUES (:user_id, :parent_id, :name, :description, :position)
        ');

        $stmt->execute([
            'user_id' => $this->getUserId(),
            'parent_id' => $data['parent_id'] ?: null,
            'name' => $data['name'],
            'description' => $data['description'] ?? null,
            'position' => $data['position'] ?? 0,
        ]);

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

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

        $project = $this->findOrFail($projectId);
        $project['tags'] = $this->getProjectTags($projectId);

        Response::success($project, 'Projet créé', 201);
    }

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

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

        $data = $this->validate([
            'name' => 'min:1|max:100',
            'description' => 'max:65535',
            'parent_id' => 'int',
            'position' => 'int',
        ]);

        // Vérifier que le parent n'est pas le projet lui-même ou un de ses enfants
        if (!empty($data['parent_id'])) {
            $parentId = (int) $data['parent_id'];
            if ($parentId === $id) {
                Response::error('Un projet ne peut pas être son propre parent', 422);
            }
            $this->findOrFail($parentId);

            // Vérifier que le parent n'est pas un enfant du projet
            if ($this->isDescendant($parentId, $id)) {
                Response::error('Le parent ne peut pas être un sous-projet', 422);
            }
        }

        $db = Database::getInstance();

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

        if (isset($data['name'])) {
            $fields[] = 'name = :name';
            $params['name'] = $data['name'];
        }

        if (array_key_exists('description', $data)) {
            $fields[] = 'description = :description';
            $params['description'] = $data['description'];
        }

        if (array_key_exists('parent_id', $data)) {
            $fields[] = 'parent_id = :parent_id';
            $params['parent_id'] = $data['parent_id'] ?: null;
        }

        if (isset($data['position'])) {
            $fields[] = 'position = :position';
            $params['position'] = $data['position'];
        }

        if (!empty($fields)) {
            $sql = 'UPDATE projects 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);
        }

        $project = $this->findOrFail($id);
        $project['tags'] = $this->getProjectTags($id);

        Response::success($project, 'Projet mis à jour');
    }

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

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

        $db = Database::getInstance();

        // Les sous-projets et tâches seront supprimés en cascade (FK)
        $stmt = $db->prepare('DELETE FROM projects WHERE id = :id');
        $stmt->execute(['id' => $id]);

        Response::success(null, 'Projet supprimé');
    }

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

        $stmt = $db->prepare('
            SELECT * FROM projects
            WHERE id = :id AND user_id = :user_id
        ');

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

        $project = $stmt->fetch();

        if (!$project) {
            Response::notFound('Projet non trouvé');
        }

        return $project;
    }

    /**
     * Construire l'arborescence des projets
     */
    private function buildTree(array $projects, ?int $parentId = null): array
    {
        $tree = [];

        foreach ($projects as $project) {
            if ($project['parent_id'] == $parentId) {
                // Parser les tags
                $project['tags'] = [];
                if (!empty($project['tag_ids'])) {
                    $ids = explode(',', $project['tag_ids']);
                    $names = explode(',', $project['tag_names']);
                    foreach ($ids as $i => $tagId) {
                        $project['tags'][] = [
                            'id' => (int) $tagId,
                            'name' => $names[$i] ?? '',
                        ];
                    }
                }
                unset($project['tag_ids'], $project['tag_names']);

                // Récursion pour les enfants
                $project['children'] = $this->buildTree($projects, (int) $project['id']);

                $tree[] = $project;
            }
        }

        return $tree;
    }

    /**
     * Récupérer les tags d'un projet
     */
    private function getProjectTags(int $projectId): array
    {
        $db = Database::getInstance();

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

        $stmt->execute(['project_id' => $projectId]);

        return $stmt->fetchAll();
    }

    /**
     * Récupérer les sous-projets directs
     */
    private function getChildren(int $projectId): array
    {
        $db = Database::getInstance();

        $stmt = $db->prepare('
            SELECT * FROM projects
            WHERE parent_id = :parent_id AND user_id = :user_id
            ORDER BY position ASC, name ASC
        ');

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

        return $stmt->fetchAll();
    }

    /**
     * Vérifier si un projet est un descendant d'un autre
     */
    private function isDescendant(int $projectId, int $ancestorId): bool
    {
        $db = Database::getInstance();

        $stmt = $db->prepare('
            SELECT parent_id FROM projects
            WHERE id = :id AND user_id = :user_id
        ');

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

        $project = $stmt->fetch();

        if (!$project || $project['parent_id'] === null) {
            return false;
        }

        if ((int) $project['parent_id'] === $ancestorId) {
            return true;
        }

        return $this->isDescendant((int) $project['parent_id'], $ancestorId);
    }

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

        // Supprimer les associations existantes
        $stmt = $db->prepare('DELETE FROM project_tags WHERE project_id = :project_id');
        $stmt->execute(['project_id' => $projectId]);

        // Ajouter les nouvelles associations
        if (!empty($tagIds)) {
            $stmt = $db->prepare('
                INSERT INTO project_tags (project_id, tag_id)
                SELECT :project_id, id FROM tags
                WHERE id = :tag_id AND user_id = :user_id
            ');

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