<?php

declare(strict_types=1);

namespace App\Repository;

use PDO;

/**
 * Data access for the `projects` table.
 *
 * @phpstan-type ProjectRow array{
 *     id: int, owner_id: int, title: string, description: string,
 *     card_count: int, completed_count: int, created_at: string, updated_at: string
 * }
 */
final class ProjectRepository
{
    private const SELECT = <<<'SQL'
        SELECT p.id, p.owner_id, p.title, p.description, p.created_at, p.updated_at,
               (SELECT COUNT(*) FROM cards c WHERE c.project_id = p.id) AS card_count,
               (SELECT COUNT(*) FROM cards c WHERE c.project_id = p.id AND c.complete = 1) AS completed_count
        FROM projects p
        SQL;

    public function __construct(private readonly PDO $pdo)
    {
    }

    /**
     * Every project owned by the user, always sorted alphabetically by title
     * (case-insensitive). There is deliberately no other ordering option.
     *
     * @return ProjectRow[]
     */
    public function allForOwner(int $ownerId): array
    {
        $stmt = $this->pdo->prepare(
            self::SELECT . ' WHERE p.owner_id = :owner ORDER BY p.title COLLATE NOCASE ASC, p.id ASC'
        );
        $stmt->execute(['owner' => $ownerId]);

        return array_map($this->cast(...), $stmt->fetchAll());
    }

    public function countForOwner(int $ownerId): int
    {
        $stmt = $this->pdo->prepare('SELECT COUNT(*) FROM projects WHERE owner_id = :owner');
        $stmt->execute(['owner' => $ownerId]);

        return (int) $stmt->fetchColumn();
    }

    /**
     * @return ProjectRow|null
     */
    public function findOwnedBy(int $id, int $ownerId): ?array
    {
        $stmt = $this->pdo->prepare(self::SELECT . ' WHERE p.id = :id AND p.owner_id = :owner');
        $stmt->execute(['id' => $id, 'owner' => $ownerId]);

        $row = $stmt->fetch();

        return $row === false ? null : $this->cast($row);
    }

    /**
     * @return ProjectRow
     */
    public function create(int $ownerId, string $title, string $description): array
    {
        $stmt = $this->pdo->prepare(
            'INSERT INTO projects (owner_id, title, description) VALUES (:owner, :title, :description)'
        );
        $stmt->execute([
            'owner' => $ownerId,
            'title' => $title,
            'description' => $description,
        ]);

        /** @var ProjectRow $project */
        $project = $this->findOwnedBy((int) $this->pdo->lastInsertId(), $ownerId);

        return $project;
    }

    /**
     * @param array{title?: string, description?: string} $fields
     * @return ProjectRow
     */
    public function update(int $id, int $ownerId, array $fields): array
    {
        $sets = ['updated_at = ' . $this->nowExpr()];
        $params = ['id' => $id];

        foreach (['title', 'description'] as $column) {
            if (array_key_exists($column, $fields)) {
                $sets[] = "{$column} = :{$column}";
                $params[$column] = $fields[$column];
            }
        }

        $stmt = $this->pdo->prepare('UPDATE projects SET ' . implode(', ', $sets) . ' WHERE id = :id');
        $stmt->execute($params);

        /** @var ProjectRow $project */
        $project = $this->findOwnedBy($id, $ownerId);

        return $project;
    }

    public function delete(int $id): void
    {
        $this->pdo->prepare('DELETE FROM projects WHERE id = :id')->execute(['id' => $id]);
    }

    /** Bump updated_at, e.g. when the project's cards change. */
    public function touch(int $id): void
    {
        $this->pdo->prepare('UPDATE projects SET updated_at = ' . $this->nowExpr() . ' WHERE id = :id')
            ->execute(['id' => $id]);
    }

    private function nowExpr(): string
    {
        return "strftime('%Y-%m-%dT%H:%M:%SZ', 'now')";
    }

    /**
     * @param array<string, mixed> $row
     * @return ProjectRow
     */
    private function cast(array $row): array
    {
        $row['id'] = (int) $row['id'];
        $row['owner_id'] = (int) $row['owner_id'];
        $row['card_count'] = (int) $row['card_count'];
        $row['completed_count'] = (int) $row['completed_count'];

        /** @var ProjectRow $row */
        return $row;
    }
}