<?php
// ============================================
// 文件: lib/db.php
// 说明: 数据库连接与初始化（建表 / 字段迁移 / 历史数据迁移 / 默认管理员）
// ============================================

// 数据库连接
function getDB() {
    try {
        $db = new PDO('sqlite:' . DB_PATH);
        $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
        return $db;
    } catch (PDOException $e) {
        die('数据库连接失败: ' . $e->getMessage());
    }
}

// 初始化数据库
function initDB() {
    $db = getDB();

    // 管理员表
    $db->exec("
        CREATE TABLE IF NOT EXISTS admins (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            username TEXT UNIQUE NOT NULL,
            password TEXT NOT NULL,
            avatar TEXT
        )
    ");

    // 电影院表
    $db->exec("
        CREATE TABLE IF NOT EXISTS cinemas (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            place TEXT NOT NULL,
            name TEXT NOT NULL,
            address TEXT,
            color TEXT DEFAULT '#888888'
        )
    ");

    // 电影表
    $db->exec("
        CREATE TABLE IF NOT EXISTS movies (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            title TEXT NOT NULL,
            info TEXT,
            remark TEXT,
            poster_path TEXT,
            ticket_path TEXT,
            photo_path TEXT,
            cinema_id INTEGER,
            watch_date DATE,
            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
            FOREIGN KEY (cinema_id) REFERENCES cinemas(id) ON DELETE SET NULL
        )
    ");

    // 观影人表
    $db->exec("
        CREATE TABLE IF NOT EXISTS persons (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL UNIQUE,
            color TEXT DEFAULT '#888888',
            avatar TEXT
        )
    ");

    // 观影关联表
    $db->exec("
        CREATE TABLE IF NOT EXISTS viewers (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            movie_id INTEGER NOT NULL,
            name TEXT,
            person_id INTEGER,
            FOREIGN KEY (movie_id) REFERENCES movies(id) ON DELETE CASCADE,
            FOREIGN KEY (person_id) REFERENCES persons(id) ON DELETE SET NULL
        )
    ");

    // 多照片表
    $db->exec("
        CREATE TABLE IF NOT EXISTS movie_photos (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            movie_id INTEGER NOT NULL,
            photo_path TEXT NOT NULL,
            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
            FOREIGN KEY (movie_id) REFERENCES movies(id) ON DELETE CASCADE
        )
    ");

    // ===== 迁移字段 =====
    try { $db->exec("ALTER TABLE cinemas ADD COLUMN color TEXT DEFAULT '#888888'"); } catch (PDOException $e) {}
    try { $db->exec("ALTER TABLE admins ADD COLUMN avatar TEXT"); } catch (PDOException $e) {}
    try { $db->exec("ALTER TABLE persons ADD COLUMN avatar TEXT"); } catch (PDOException $e) {}
    try { $db->exec("ALTER TABLE movies ADD COLUMN remark TEXT"); } catch (PDOException $e) {}
    try { $db->exec("ALTER TABLE viewers ADD COLUMN person_id INTEGER REFERENCES persons(id) ON DELETE SET NULL"); } catch (PDOException $e) {}
    // 新增：管理员关联观影人
    try { $db->exec("ALTER TABLE admins ADD COLUMN person_id INTEGER REFERENCES persons(id) ON DELETE SET NULL"); } catch (PDOException $e) {}

    // ===== 迁移旧数据 =====
    // 将 viewers.name 迁移到 persons
    $stmt = $db->query("SELECT DISTINCT name FROM viewers WHERE name != '' AND name IS NOT NULL");
    $names = $stmt->fetchAll(PDO::FETCH_COLUMN);
    foreach ($names as $name) {
        $chk = $db->prepare("SELECT id FROM persons WHERE name = ?");
        $chk->execute([$name]);
        if (!$chk->fetch()) {
            $ins = $db->prepare("INSERT INTO persons (name) VALUES (?)");
            $ins->execute([$name]);
        }
    }
    $update = $db->prepare("UPDATE viewers SET person_id = (SELECT id FROM persons WHERE persons.name = viewers.name) WHERE person_id IS NULL AND name IS NOT NULL");
    $update->execute();

    // 默认管理员
    $stmt = $db->prepare("SELECT COUNT(*) FROM admins");
    $stmt->execute();
    if ($stmt->fetchColumn() == 0) {
        $hashed = password_hash('123456', PASSWORD_DEFAULT);
        $stmt = $db->prepare("INSERT INTO admins (username, password) VALUES (?, ?)");
        $stmt->execute(['admin', $hashed]);
    }
}