<?php
declare(strict_types=1);

function app_config(): array
{
    static $config = null;
    if ($config === null) {
        $config = require __DIR__ . '/../config.php';
        date_default_timezone_set($config['app']['timezone']);
    }
    return $config;
}

/**
 * Shared PDO connection. Web requests only connect: the schema is created and
 * upgraded explicitly (database/migrate.php or the SQL files in database/),
 * never on each request.
 */
function db(): PDO
{
    static $pdo = null;
    if ($pdo instanceof PDO) {
        return $pdo;
    }
    $c = app_config()['db'];
    if ($c['user'] === '') {
        throw new RuntimeException('Kredensial database belum dikonfigurasi (lihat database/secrets.example.php).');
    }
    $pdo = db_connect($c, true);
    $pdo->exec("SET time_zone = '" . (new DateTime())->format('P') . "'");
    return $pdo;
}

function db_connect(array $c, bool $withDatabase): PDO
{
    $dsn = sprintf('mysql:host=%s;port=%d;charset=utf8mb4', $c['host'], $c['port']);
    if ($withDatabase) {
        $dsn .= ';dbname=' . str_replace('`', '', $c['name']);
    }
    return new PDO($dsn, $c['user'], $c['password'], [
        PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        PDO::ATTR_EMULATE_PREPARES   => false,
    ]);
}

/** Runs a trusted SQL file; statements end with ";" at the end of a line (no splitting inside literals). */
function db_run_sql_file(PDO $pdo, string $file): void
{
    $sql = preg_replace('/^\s*--.*$/m', '', (string)file_get_contents($file));
    foreach (preg_split('/;\s*$/m', $sql) as $stmt) {
        if (trim($stmt) !== '') {
            $pdo->exec($stmt);
        }
    }
}

/** CLI only (database/migrate.php): creates the tables and seed data on an empty database. */
function db_migrate(PDO $pdo): void
{
    $exists = $pdo->query("SHOW TABLES LIKE 'login_attempts'")->fetchColumn();
    if (!$exists) {
        db_run_sql_file($pdo, __DIR__ . '/../database/schema.sql');
    }
    if ((int)$pdo->query('SELECT COUNT(*) FROM settings')->fetchColumn() === 0) {
        db_seed($pdo);
    }
    db_clean_descriptions($pdo);
}

/** Removes workbook cell references like " (COB!F28)" from older seeded descriptions (runs until none are left). */
function db_clean_descriptions(PDO $pdo): void
{
    $rows = $pdo->query("SELECT skey, description FROM settings WHERE description LIKE '%COB!%' OR description LIKE '%CALC!%'")->fetchAll();
    if (!$rows) {
        return;
    }
    $st = $pdo->prepare('UPDATE settings SET description = ? WHERE skey = ?');
    foreach ($rows as $r) {
        $st->execute([trim(preg_replace('/\s*\((?:COB|CALC)![A-Z0-9:]+\)/', '', (string)$r['description'])), $r['skey']]);
    }
}

/** Seeds parameters from database/defaults.php (the values of the reference workbook). */
function db_seed(PDO $pdo, bool $wipe = false): void
{
    $d = require __DIR__ . '/../database/defaults.php';
    $pdo->beginTransaction();
    try {
        if ($wipe) {
            foreach (['deposito_rates', 'deposito_bands', 'product_rates', 'cashback_tiers', 'tenors', 'settings'] as $t) {
                $pdo->exec("DELETE FROM $t");
            }
        }
        $st = $pdo->prepare('INSERT INTO settings (skey, value, label, unit, grp, description, sort) VALUES (?,?,?,?,?,?,?)');
        $i = 0;
        foreach ($d['settings'] as $key => [$value, $label, $unit, $grp, $desc]) {
            $st->execute([$key, $value, $label, $unit, $grp, $desc, ++$i]);
        }
        $st = $pdo->prepare('INSERT INTO tenors (months, cashback) VALUES (?,?)');
        foreach ($d['tenors'] as $m => $cb) {
            $st->execute([$m, $cb ? 1 : 0]);
        }
        $st = $pdo->prepare('INSERT INTO product_rates (product, max_nominal, rate, sort) VALUES (?,?,?,?)');
        foreach ($d['product_rates'] as $product => $tiers) {
            foreach ($tiers as $i => [$max, $rate]) {
                $st->execute([$product, $max, $rate, $i]);
            }
        }
        $band = $pdo->prepare('INSERT INTO deposito_bands (max_nominal, sort) VALUES (?,?)');
        $rate = $pdo->prepare('INSERT INTO deposito_rates (band_id, tenor, rate) VALUES (?,?,?)');
        foreach ($d['deposito_bands'] as $i => $max) {
            $band->execute([$max, $i]);
            $bandId = (int)$pdo->lastInsertId();
            foreach ($d['deposito_rates'] as $tenor => $rates) {
                $rate->execute([$bandId, $tenor, $rates[$i]]);
            }
        }
        $st = $pdo->prepare('INSERT INTO cashback_tiers (min_nominal, share_nasabah) VALUES (?,?)');
        foreach ($d['cashback_tiers'] as [$min, $share]) {
            $st->execute([$min, $share]);
        }
        $pdo->commit();
    } catch (Throwable $e) {
        $pdo->rollBack();
        throw $e;
    }
}