<?php
session_start();

$lockFile = __DIR__ . '/../installed.lock';
if (file_exists($lockFile)) {
    die("Installation already completed. Please remove 'installed.lock' if you want to re-install.");
}

$step = isset($_GET['step']) ? (int)$_GET['step'] : 1;
$error = '';
$success = '';

function installationMigrationSortKey(string $filePath): string {
    $basename = basename($filePath);

    return match ($basename) {
        '20260318_add_outlet_id_to_purchases.sql' => '20260318_10_add_outlet_id_to_purchases.sql',
        '20260318_create_outlets_table.sql' => '20260318_20_create_outlets_table.sql',
        '20260318_multi_outlet_schema.sql' => '20260318_30_multi_outlet_schema.sql',
        '20260318_local_definitions.sql' => '20260318_40_local_definitions.sql',
        '20260318_user_outlets_table.sql' => '20260318_50_user_outlets_table.sql',
        default => $basename,
    };
}

function installationLegacyNumberedMigrationFile(string $filePath): bool {
    // Skip obsolete pre-date-based migrations from older packaged builds.
    return preg_match('/^\d{1,7}_/', basename($filePath)) === 1;
}

function installationMigrationFiles(): array {
    $files = array_merge(
        glob(__DIR__ . '/../db/migrations/*.sql') ?: [],
        glob(__DIR__ . '/../db/migrations/*.php') ?: []
    );

    $files = array_values(array_filter($files, static function (string $filePath): bool {
        return !installationLegacyNumberedMigrationFile($filePath);
    }));

    usort($files, static function (string $left, string $right): int {
        return strnatcasecmp(installationMigrationSortKey($left), installationMigrationSortKey($right));
    });

    return $files;
}

function installationBuildDsn(string $host, ?string $dbName = null): string {
    $normalizedHost = trim($host);
    $port = null;

    if (substr_count($normalizedHost, ':') === 1) {
        [$hostPart, $portPart] = explode(':', $normalizedHost, 2);
        if ($hostPart !== '' && ctype_digit($portPart)) {
            $normalizedHost = $hostPart;
            $port = $portPart;
        }
    }

    $dsn = 'mysql:host=' . $normalizedHost;
    if ($port !== null) {
        $dsn .= ';port=' . $port;
    }
    if ($dbName !== null && $dbName !== '') {
        $dsn .= ';dbname=' . $dbName;
    }

    return $dsn . ';charset=utf8mb4';
}

function installationQuoteIdentifier(string $identifier): string {
    return '`' . str_replace('`', '``', $identifier) . '`';
}

function installationBuildConfigContent(string $host, string $name, string $user, string $pass): string {
    return sprintf(
        <<<'PHP'
<?php
define('DB_HOST', %s);
define('DB_NAME', %s);
define('DB_USER', %s);
define('DB_PASS', %s);

function db() {
  static $pdo;
  if (!$pdo) {
    $pdo = new PDO('mysql:host='.DB_HOST.';dbname='.DB_NAME.';charset=utf8mb4', DB_USER, DB_PASS, [
      PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
      PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    ]);
    if (session_status() === PHP_SESSION_NONE && !headers_sent()) {
        @session_start();
    }
    if (isset($_SESSION['outlet_id'])) {
        $pdo->exec("SET @session_outlet_id = " . (int)$_SESSION['outlet_id']);
    } else {
        $pdo->exec("SET @session_outlet_id = 0");
    }
  }
  return $pdo;
}

PHP,
        var_export($host, true),
        var_export($name, true),
        var_export($user, true),
        var_export($pass, true)
    );
}

// Step 1: Requirements
if ($step === 1) {
    $requirements = [
        'php_version' => [
            'name' => 'PHP Version (>= 8.0)',
            'status' => version_compare(PHP_VERSION, '8.0.0', '>='),
            'current' => PHP_VERSION
        ],
        'pdo_mysql' => [
            'name' => 'PDO MySQL Extension',
            'status' => extension_loaded('pdo_mysql'),
            'current' => extension_loaded('pdo_mysql') ? 'Loaded' : 'Missing'
        ],
        'curl' => [
            'name' => 'cURL Extension (Required for Licensing)',
            'status' => extension_loaded('curl'),
            'current' => extension_loaded('curl') ? 'Loaded' : 'Missing'
        ],
        'config_writable' => [
            'name' => 'db/config.php Writable',
            'status' => is_writable(__DIR__ . '/../db/config.php'),
            'current' => is_writable(__DIR__ . '/../db/config.php') ? 'Yes' : 'No'
        ],
        'root_writable' => [
            'name' => 'Root Directory Writable',
            'status' => is_writable(__DIR__ . '/..'),
            'current' => is_writable(__DIR__ . '/..') ? 'Yes' : 'No'
        ]
    ];
    $allOk = true;
    foreach ($requirements as $req) {
        if (!$req['status']) $allOk = false;
    }
}

// Step 2: Database
if ($step === 2 && $_SERVER['REQUEST_METHOD'] === 'POST') {
    $host = trim((string) ($_POST['db_host'] ?? ''));
    $name = trim((string) ($_POST['db_name'] ?? ''));
    $user = trim((string) ($_POST['db_user'] ?? ''));
    $pass = (string) ($_POST['db_pass'] ?? '');

    if ($host === '' || $name === '' || $user === '') {
        $error = 'Database host, name, and user are required.';
    } else {
        try {
            $pdoOptions = [
                PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            ];

            try {
                $pdo = new PDO(installationBuildDsn($host, $name), $user, $pass, $pdoOptions);
            } catch (PDOException $connectionException) {
                $pdo = new PDO(installationBuildDsn($host), $user, $pass, $pdoOptions);
                $pdo->exec('CREATE DATABASE IF NOT EXISTS ' . installationQuoteIdentifier($name) . ' CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci');
            }

            $configPath = __DIR__ . '/../db/config.php';
            $bytesWritten = file_put_contents($configPath, installationBuildConfigContent($host, $name, $user, $pass));
            if ($bytesWritten === false) {
                throw new RuntimeException('Unable to write db/config.php');
            }

            require_once __DIR__ . '/../includes/DatabaseInstaller.php';
            DatabaseInstaller::install();

            header("Location: index.php?step=3");
            exit;
        } catch (Throwable $e) {
            $error = "Database Setup Failed: " . $e->getMessage();
        }
    }
}

// Step 3: Super Admin
if ($step === 3 && $_SERVER['REQUEST_METHOD'] === 'POST') {
    require_once __DIR__ . '/../db/config.php';
    $adminUser = $_POST['admin_user'] ?? '';
    $adminPass = $_POST['admin_pass'] ?? '';
    $adminEmail = $_POST['admin_email'] ?? '';

    try {
        require_once __DIR__ . '/../includes/DatabaseInstaller.php';
        if (!DatabaseInstaller::isInstalled()) {
            DatabaseInstaller::install();
        } else {
            DatabaseInstaller::ensureCurrentSchema();
        }
        $pdo = db();

        // Ensure Admin Role exists (might be in schema but just in case)
        $stmt = $pdo->prepare("SELECT id FROM role_groups WHERE name = 'Administrator'");
        $stmt->execute();
        $role = $stmt->fetch();
        if (!$role) {
            $pdo->exec("INSERT INTO role_groups (name) VALUES ('Administrator')");
            $roleId = $pdo->lastInsertId();
            $pdo->exec("INSERT INTO role_permissions (role_id, permission) VALUES ($roleId, 'all')");
        } else {
            $roleId = $role['id'];
            // Also ensure 'all' permission exists for it
            $stmt = $pdo->prepare("SELECT id FROM role_permissions WHERE role_id = ? AND permission = 'all'");
            $stmt->execute([$roleId]);
            if (!$stmt->fetch()) {
                $pdo->exec("INSERT INTO role_permissions (role_id, permission) VALUES ($roleId, 'all')");
            }
        }

        // Insert Admin User (Use ON DUPLICATE KEY UPDATE to handle existing user from schema)
        $hashedPass = password_hash($adminPass, PASSWORD_DEFAULT);
        $stmt = $pdo->prepare("INSERT INTO users (username, password, email, group_id, status) 
                               VALUES (?, ?, ?, ?, 'active')
                               ON DUPLICATE KEY UPDATE 
                               password = VALUES(password), 
                               email = VALUES(email), 
                               group_id = VALUES(group_id), 
                               status = 'active'");
        $stmt->execute([$adminUser, $hashedPass, $adminEmail, $roleId]);

        header("Location: index.php?step=4");
        exit;
    } catch (Exception $e) {
        $error = "Setup Failed: " . $e->getMessage();
    }
}

// Step 4: Finish
if ($step === 4) {
    file_put_contents($lockFile, date('Y-m-d H:i:s'));
}

?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="robots" content="noindex, nofollow">
    <title>Installation - Step <?= $step ?></title>
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet">
    <link href="https://cdn.jsdelivr.net/npm/bootstrap-icons@1.10.0/font/bootstrap-icons.css" rel="stylesheet">
    <style>
        body { background: #f0f2f5; font-family: 'Inter', sans-serif; display: flex; align-items: center; justify-content: center; min-height: 100vh; margin: 0; }
        .install-container { width: 100%; max-width: 600px; padding: 20px; }
        .card { border: none; border-radius: 20px; box-shadow: 0 10px 40px rgba(0,0,0,0.08); overflow: hidden; }
        .card-header { background: linear-gradient(135deg, #6e8efb, #a777e3); color: white; border: none; padding: 30px; text-align: center; }
        .step-indicator { display: flex; justify-content: space-between; margin-bottom: 30px; position: relative; }
        .step-indicator::before { content: ''; position: absolute; top: 15px; left: 0; right: 0; height: 2px; background: #e0e0e0; z-index: 1; }
        .step-dot { width: 32px; height: 32px; background: #fff; border: 2px solid #e0e0e0; border-radius: 50%; display: flex; align-items: center; justify-content: center; z-index: 2; font-weight: bold; font-size: 14px; color: #999; }
        .step-dot.active { border-color: #6e8efb; color: #6e8efb; background: #fff; box-shadow: 0 0 10px rgba(110, 142, 251, 0.3); }
        .step-dot.completed { background: #6e8efb; border-color: #6e8efb; color: #fff; }
        .btn-primary { background: linear-gradient(135deg, #6e8efb, #a777e3); border: none; border-radius: 12px; padding: 12px 24px; font-weight: 600; }
        .form-control { border-radius: 12px; padding: 12px; border: 1px solid #dee2e6; }
    </style>
</head>
<body>
    <div class="install-container">
        <div class="card">
            <div class="card-header">
                <h3 class="fw-bold mb-0">System Installation</h3>
                <p class="mb-0 opacity-75">Configure your application in minutes</p>
            </div>
            <div class="card-body p-4 p-md-5">
                <div class="step-indicator">
                    <div class="step-dot <?= $step >= 1 ? ($step > 1 ? 'completed' : 'active') : '' ?>"><?= $step > 1 ? '<i class="bi bi-check"></i>' : '1' ?></div>
                    <div class="step-dot <?= $step >= 2 ? ($step > 2 ? 'completed' : 'active') : '' ?>"><?= $step > 2 ? '<i class="bi bi-check"></i>' : '2' ?></div>
                    <div class="step-dot <?= $step >= 3 ? ($step > 3 ? 'completed' : 'active') : '' ?>"><?= $step > 3 ? '<i class="bi bi-check"></i>' : '3' ?></div>
                    <div class="step-dot <?= $step >= 4 ? 'completed' : '' ?>">4</div>
                </div>

                <?php if ($error): ?>
                    <div class="alert alert-danger d-flex align-items-center mb-4">
                        <i class="bi bi-exclamation-triangle-fill me-2"></i>
                        <div><?= $error ?></div>
                    </div>
                <?php endif; ?>

                <?php if ($step === 1): ?>
                    <h5 class="fw-bold mb-4">Step 1: Check Requirements</h5>
                    <div class="list-group list-group-flush mb-4">
                        <?php foreach ($requirements as $req): ?>
                            <div class="list-group-item d-flex justify-content-between align-items-center py-3">
                                <div>
                                    <h6 class="mb-0 fw-semibold"><?= $req['name'] ?></h6>
                                    <small class="text-muted">Current: <?= $req['current'] ?></small>
                                </div>
                                <?php if ($req['status']): ?>
                                    <span class="badge bg-success-subtle text-success rounded-pill px-3">Passed</span>
                                <?php else: ?>
                                    <span class="badge bg-danger-subtle text-danger rounded-pill px-3">Failed</span>
                                <?php endif; ?>
                            </div>
                        <?php endforeach; ?>
                    </div>
                    <?php if ($allOk): ?>
                        <div class="d-grid">
                            <a href="index.php?step=2" class="btn btn-primary">Next: Database Setup</a>
                        </div>
                    <?php else: ?>
                        <div class="alert alert-warning small">Please fix the issues above to continue.</div>
                        <div class="d-grid">
                            <button onclick="window.location.reload()" class="btn btn-secondary">Retry Check</button>
                        </div>
                    <?php endif; ?>

                <?php elseif ($step === 2): ?>
                    <h5 class="fw-bold mb-4">Step 2: Database Configuration</h5>
                    <form method="POST">
                        <div class="mb-3">
                            <label class="form-label small fw-bold">Database Host</label>
                            <input type="text" name="db_host" class="form-control" value="127.0.0.1" required>
                        </div>
                        <div class="mb-3">
                            <label class="form-label small fw-bold">Database Name</label>
                            <input type="text" name="db_name" class="form-control" placeholder="e.g. admin_db" required>
                        </div>
                        <div class="mb-3">
                            <label class="form-label small fw-bold">Database User</label>
                            <input type="text" name="db_user" class="form-control" placeholder="e.g. root" required>
                        </div>
                        <div class="mb-3">
                            <label class="form-label small fw-bold">Database Password</label>
                            <input type="password" name="db_pass" class="form-control" placeholder="Enter password">
                        </div>
                        <div class="d-grid mt-4">
                            <button type="submit" class="btn btn-primary">Verify, Save & Import Schema</button>
                        </div>
                    </form>
                    <div class="alert alert-info small mt-3 mb-0">This step creates the database tables and imports the base schema before you add the admin account.</div>

                <?php elseif ($step === 3): ?>
                    <h5 class="fw-bold mb-4">Step 3: Super Admin Setup</h5>
                    <form method="POST">
                        <div class="mb-3">
                            <label class="form-label small fw-bold">Admin Username</label>
                            <input type="text" name="admin_user" class="form-control" placeholder="e.g. admin" required>
                        </div>
                        <div class="mb-3">
                            <label class="form-label small fw-bold">Admin Email</label>
                            <input type="email" name="admin_email" class="form-control" placeholder="admin@example.com" required>
                        </div>
                        <div class="mb-3">
                            <label class="form-label small fw-bold">Admin Password</label>
                            <input type="password" name="admin_pass" class="form-control" placeholder="Minimum 6 characters" required minlength="6">
                        </div>
                        <div class="d-grid mt-4">
                            <button type="submit" class="btn btn-primary">Finish Installation</button>
                        </div>
                    </form>

                <?php elseif ($step === 4): ?>
                    <div class="text-center py-4">
                        <div class="display-1 text-success mb-4">
                            <i class="bi bi-check-circle-fill"></i>
                        </div>
                        <h4 class="fw-bold">Ready to Launch!</h4>
                        <p class="text-muted">Installation completed successfully. Your system is now secure and ready to use.</p>
                        <div class="alert alert-info small mt-4">
                            <i class="bi bi-info-circle me-2"></i>
                            For security, the <code>installed.lock</code> file has been created.
                        </div>
                        <div class="d-grid mt-5">
                            <a href="../index.php" class="btn btn-primary">Go to Dashboard</a>
                        </div>
                    </div>
                <?php endif; ?>
            </div>
        </div>
    </div>
</body>
</html>