<?php
declare(strict_types=1);

require_once __DIR__ . '/config.php';

function db(): PDO
{
    static $pdo = null;
    if ($pdo instanceof PDO) {
        return $pdo;
    }

    $pdo = new PDO('sqlite:' . DB_PATH);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
    $pdo->exec('PRAGMA foreign_keys = ON');

    initSchema($pdo);
    seedAdmin($pdo);
    return $pdo;
}

function initSchema(PDO $pdo): void
{
    $pdo->exec("
        CREATE TABLE IF NOT EXISTS users (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            username TEXT UNIQUE NOT NULL,
            password_hash TEXT NOT NULL,
            role TEXT NOT NULL CHECK(role IN ('admin','user')),
            created_at TEXT NOT NULL
        );
    ");

    $pdo->exec("
        CREATE TABLE IF NOT EXISTS directories (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL,
            parent_id INTEGER NULL,
            level INTEGER NOT NULL CHECK(level BETWEEN 1 AND 3),
            created_at TEXT NOT NULL,
            FOREIGN KEY(parent_id) REFERENCES directories(id) ON DELETE CASCADE
        );
    ");

    $pdo->exec("
        CREATE TABLE IF NOT EXISTS archives (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL,
            directory_id INTEGER NOT NULL,
            loan_institution TEXT,
            borrower TEXT,
            credit_limit REAL,
            remaining_limit REAL,
            start_date TEXT,
            end_date TEXT,
            annual_rate REAL,
            guarantee_type TEXT,
            guarantor TEXT,
            archive_kind TEXT NOT NULL DEFAULT 'bank_loan',
            created_at TEXT NOT NULL,
            updated_at TEXT NOT NULL,
            FOREIGN KEY(directory_id) REFERENCES directories(id) ON DELETE CASCADE
        );
    ");

    $hasArchiveKind = false;
    foreach ($pdo->query('PRAGMA table_info(archives)')->fetchAll(PDO::FETCH_ASSOC) as $col) {
        if (($col['name'] ?? '') === 'archive_kind') {
            $hasArchiveKind = true;
            break;
        }
    }
    if (!$hasArchiveKind) {
        $pdo->exec("ALTER TABLE archives ADD COLUMN archive_kind TEXT NOT NULL DEFAULT 'bank_loan'");
    }

    $pdo->exec("
        CREATE TABLE IF NOT EXISTS files (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            archive_id INTEGER NOT NULL,
            original_name TEXT NOT NULL,
            stored_name TEXT NOT NULL,
            file_ext TEXT NOT NULL,
            file_size INTEGER NOT NULL,
            created_at TEXT NOT NULL,
            FOREIGN KEY(archive_id) REFERENCES archives(id) ON DELETE CASCADE
        );
    ");

    $pdo->exec("CREATE INDEX IF NOT EXISTS idx_archives_end_date ON archives(end_date)");
    $pdo->exec("CREATE INDEX IF NOT EXISTS idx_archives_loan_inst ON archives(loan_institution)");
    $pdo->exec("CREATE INDEX IF NOT EXISTS idx_archives_borrower ON archives(borrower)");
}

function seedAdmin(PDO $pdo): void
{
    $stmt = $pdo->prepare('SELECT COUNT(*) FROM users WHERE username = :username');
    $stmt->execute([':username' => 'admin']);
    if ((int)$stmt->fetchColumn() > 0) {
        return;
    }
    $stmt = $pdo->prepare('INSERT INTO users(username,password_hash,role,created_at) VALUES(:u,:p,:r,:c)');
    $stmt->execute([
        ':u' => 'admin',
        ':p' => password_hash('jinniu123', PASSWORD_DEFAULT),
        ':r' => 'admin',
        ':c' => date('Y-m-d H:i:s'),
    ]);
}