<?php
// Sheet Management Helper Functions

function getMetadataPath() {
    return __DIR__ . '/sheets_metadata.json';
}

function getSheetPath($user, $sheetId) {
    $safeUser = str_replace(['@', '.'], ['_at_', '_'], $user);
    return __DIR__ . "/sheets/{$safeUser}_{$sheetId}.json";
}

function loadMetadata() {
    $path = getMetadataPath();
    if (!file_exists($path)) {
        return [];
    }
    $content = file_get_contents($path);
    return json_decode($content, true) ?: [];
}

function saveMetadata($metadata) {
    $path = getMetadataPath();
    file_put_contents($path, json_encode($metadata, JSON_PRETTY_PRINT));
    chmod($path, 0666); // Ensure writable
}

function getUserSheets($user) {
    $metadata = loadMetadata();
    return $metadata[$user] ?? [];
}

function createSheet($user, $name, $data = []) {
    $sheetId = time() . rand(100, 999);
    $now = date('c');
    
    $sheet = [
        'id' => $sheetId,
        'name' => $name ?: "Untitled Sheet - " . date('Y-m-d H:i'),
        'created' => $now,
        'modified' => $now,
        'itemCount' => count($data),
        'user' => $user
    ];
    
    // Save sheet data
    $sheetPath = getSheetPath($user, $sheetId);
    file_put_contents($sheetPath, json_encode($data, JSON_PRETTY_PRINT));
    chmod($sheetPath, 0666); // Ensure writable
    
    // Update metadata
    $metadata = loadMetadata();
    if (!isset($metadata[$user])) {
        $metadata[$user] = [];
    }
    $metadata[$user][] = $sheet;
    saveMetadata($metadata);
    
    return $sheet;
}

function loadSheetData($user, $sheetId) {
    $sheetPath = getSheetPath($user, $sheetId);
    if (!file_exists($sheetPath)) {
        return null;
    }
    $content = file_get_contents($sheetPath);
    return json_decode($content, true);
}

function updateSheet($user, $sheetId, $data) {
    // Update sheet data
    $sheetPath = getSheetPath($user, $sheetId);
    file_put_contents($sheetPath, json_encode($data, JSON_PRETTY_PRINT));
    chmod($sheetPath, 0666); // Ensure writable
    
    // Update metadata
    $metadata = loadMetadata();
    if (isset($metadata[$user])) {
        foreach ($metadata[$user] as &$sheet) {
            if ($sheet['id'] == $sheetId) {
                $sheet['modified'] = date('c');
                $sheet['itemCount'] = count($data);
                break;
            }
        }
        saveMetadata($metadata);
    }
}

function deleteSheet($user, $sheetId) {
    // Delete sheet file
    $sheetPath = getSheetPath($user, $sheetId);
    if (file_exists($sheetPath)) {
        unlink($sheetPath);
    }
    
    // Update metadata
    $metadata = loadMetadata();
    if (isset($metadata[$user])) {
        $metadata[$user] = array_filter($metadata[$user], function($sheet) use ($sheetId) {
            return $sheet['id'] != $sheetId;
        });
        $metadata[$user] = array_values($metadata[$user]); // Re-index
        saveMetadata($metadata);
    }
}

function renameSheet($user, $sheetId, $newName) {
    $metadata = loadMetadata();
    if (isset($metadata[$user])) {
        foreach ($metadata[$user] as &$sheet) {
            if ($sheet['id'] == $sheetId) {
                $sheet['name'] = $newName;
                $sheet['modified'] = date('c');
                break;
            }
        }
        saveMetadata($metadata);
        return true;
    }
    return false;
}

function duplicateSheet($user, $sheetId) {
    // Load original sheet
    $originalData = loadSheetData($user, $sheetId);
    if (!$originalData) {
        return null;
    }
    
    // Get original name
    $metadata = loadMetadata();
    $originalName = "Copy of Sheet";
    if (isset($metadata[$user])) {
        foreach ($metadata[$user] as $sheet) {
            if ($sheet['id'] == $sheetId) {
                $originalName = "Copy of " . $sheet['name'];
                break;
            }
        }
    }
    
    // Create new sheet
    return createSheet($user, $originalName, $originalData);
}
?>