<?php
// dashboard.php

// Start session to store GA data and manage state
session_start();

// Configuration and token management
$google_analytics_connected = file_exists('db/google_tokens.json');
$ga_property_id = null;
$ga_data = null;
$ga_error = null;

// Handle GA Property ID submission
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['ga_property_id'])) {
    $property_id = trim($_POST['ga_property_id']);
    if (!empty($property_id)) {
        file_put_contents('db/ga_property_id.txt', $property_id);
        // Clear previous GA data on new ID
        if (isset($_SESSION['ga_data'])) unset($_SESSION['ga_data']);
        if (isset($_SESSION['ga_error'])) unset($_SESSION['ga_error']);
        
        // Set a flag to indicate we need to fetch data
        $_SESSION['ga_fetch_required'] = true;

        header('Location: dashboard.php');
        exit();
    }
}

// Load GA Property ID if it exists
if (file_exists('db/ga_property_id.txt')) {
    $ga_property_id = file_get_contents('db/ga_property_id.txt');
}

// --- GOOGLE ANALYTICS DATA FETCHING ---
// Fetch data only if connected, property ID is set, and a fetch is required
if ($google_analytics_connected && $ga_property_id && isset($_SESSION['ga_fetch_required'])) {
    unset($_SESSION['ga_fetch_required']); // Unset the flag to prevent re-fetching on every page load

    require_once 'google-config.php';
    $tokens_json = file_get_contents('db/google_tokens.json');
    $tokens = json_decode($tokens_json, true);

    if (!is_array($tokens) || !isset($tokens['access_token']) || !isset($tokens['refresh_token'])) {
        $_SESSION['ga_error'] = "Google token file is corrupt or invalid. Please disconnect and reconnect.";
        error_log("Invalid google_tokens.json content: " . $tokens_json);
        header('Location: dashboard.php');
        exit();
    }
    
    $access_token = $tokens['access_token'];
    $refresh_token = $tokens['refresh_token'];

    // --- 1. Refresh Access Token ---
    $token_url = 'https://oauth2.googleapis.com/token';
    $token_params = [
        'client_id' => GOOGLE_CLIENT_ID,
        'client_secret' => GOOGLE_CLIENT_SECRET,
        'refresh_token' => $refresh_token,
        'grant_type' => 'refresh_token'
    ];

    $ch = curl_init($token_url);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($token_params));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($http_code == 200) {
        $new_token_data = json_decode($response, true);
        if (isset($new_token_data['access_token'])) {
            $tokens['access_token'] = $new_token_data['access_token'];
            file_put_contents('db/google_tokens.json', json_encode($tokens));
            $access_token = $new_token_data['access_token'];

            // --- 2. Fetch Data from Google Analytics Data API ---
            $analytics_api_url = "https://analyticsdata.googleapis.com/v1beta/properties/{$ga_property_id}:runReport";

            $api_request_body = [
                'dateRanges' => [['startDate' => '28daysAgo', 'endDate' => 'today']],
                'metrics' => [
                    ['name' => 'sessions'],
                    ['name' => 'totalUsers'],
                    ['name' => 'screenPageViews'],
                    ['name' => 'bounceRate']
                ]
            ];

            $ch_analytics = curl_init($analytics_api_url);
            curl_setopt($ch_analytics, CURLOPT_HTTPHEADER, [
                'Authorization: Bearer ' . $access_token,
                'Content-Type: application/json'
            ]);
            curl_setopt($ch_analytics, CURLOPT_POST, true);
            curl_setopt($ch_analytics, CURLOPT_POSTFIELDS, json_encode($api_request_body));
            curl_setopt($ch_analytics, CURLOPT_RETURNTRANSFER, true);

            $analytics_response = curl_exec($ch_analytics);
            $analytics_http_code = curl_getinfo($ch_analytics, CURLINFO_HTTP_CODE);
            curl_close($ch_analytics);

            if ($analytics_http_code == 200) {
                $report = json_decode($analytics_response, true);
                if (isset($report['rows'][0]['metricValues'])) {
                    $metricValues = $report['rows'][0]['metricValues'];
                    $_SESSION['ga_data'] = [
                        'sessions' => $metricValues[0]['value'] ?? '0',
                        'users' => $metricValues[1]['value'] ?? '0',
                        'page_views' => $metricValues[2]['value'] ?? '0',
                        'bounce_rate' => isset($metricValues[3]['value']) ? round($metricValues[3]['value'] * 100, 2) . '%' : '0%',
                    ];
                } else {
                    $_SESSION['ga_error'] = "No data returned from Analytics. Check if the property ID is correct and has recent data.";
                }
            } else {
                $error_response = json_decode($analytics_response, true);
                $error_message = "HTTP {$analytics_http_code}";
                if (is_array($error_response) && isset($error_response['error']['message'])) {
                    $error_message = $error_response['error']['message'];
                } else {
                    error_log("Unknown Google API Error. Code: {$analytics_http_code}. Response: " . $analytics_response);
                }
                $_SESSION['ga_error'] = "Error fetching Analytics data: " . $error_message;
            }
        } else {
            $_SESSION['ga_error'] = "Failed to refresh token, new access token not found.";
        }
    } else {
        $_SESSION['ga_error'] = "Error refreshing Google token. Please try disconnecting and reconnecting.";
    }
    
    // Redirect to clean the URL and prevent re-submission
    header('Location: dashboard.php');
    exit();
}

// Load data from session if available
if (isset($_SESSION['ga_data'])) {
    $ga_data = $_SESSION['ga_data'];
    unset($_SESSION['ga_data']); // Clear after loading
}
if (isset($_SESSION['ga_error'])) {
    $ga_error = $_SESSION['ga_error'];
    unset($_SESSION['ga_error']); // Clear after loading
}


// Dummy data for other sections (can be replaced later)
$client_name = "Example Client";
$chart_data = [
    "labels" => ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"],
    "values" => [5000, 5500, 6200, 7100, 8000, 8500, 9200, 9800, 10500, 11200, 12000, 12345],
];
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title><?php echo htmlspecialchars($client_name); ?> - Marketing Dashboard</title>
    <link href="https://fonts.googleapis.com/css2?family=Georgia:wght@700&family=Helvetica+Neue:wght@400&display=swap" rel="stylesheet">
    <link rel="stylesheet" href="assets/css/custom.css">
</head>
<body>

    <header class="dashboard-header">
        <div class="logo">
            <a href="index.php">AgencyMoguls</a>
        </div>
        <nav class="dashboard-nav">
            <a href="#overview" class="active">Overview</a>
            <a href="#reports">Reports</a>
            <a href="#settings">Settings</a>
            <a href="index.php" class="logout-btn">Logout</a>
        </nav>
    </header>

    <main class="dashboard-main">
        <div class="integration-connect">
            <?php if ($google_analytics_connected): ?>
                <div class="ga-status-connected">Connected to Google Analytics</div>
                <a href="google_disconnect.php" class="btn btn-secondary">Disconnect</a>
            <?php else: ?>
                <a href="google_auth.php" class="btn btn-primary">Connect to Google Analytics</a>
            <?php endif; ?>
        </div>
        <div class="dashboard-title">
            <h1><?php echo htmlspecialchars($client_name); ?>'s Dashboard</h1>
            <div class="date-range-picker">
                <input type="text" value="Last 28 Days">
                <svg width="14" height="8" viewBox="0 0 14 8" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M1 1L7 7L13 1" stroke="#6C757D" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"/></svg>
            </div>
        </div>

        <?php if ($google_analytics_connected): ?>
            <?php if (!$ga_property_id): ?>
                <section class="ga-property-id-section">
                    <h2>Enter your Google Analytics Property ID</h2>
                    <p>This is required to fetch data from your Analytics account.</p>
                    <form method="POST" action="dashboard.php">
                        <input type="text" name="ga_property_id" placeholder="Enter your Property ID (e.g., 123456789)" required>
                        <button type="submit" class="btn btn-primary">Save and Fetch Data</button>
                    </form>
                </section>
            <?php else: ?>
                <section class="ga-data-section">
                    <h2>Google Analytics Overview <span class="ga-property-id">(Property ID: <?php echo htmlspecialchars($ga_property_id); ?>)</span></h2>
                    
                    <?php if ($ga_error): ?>
                        <div class="ga-error-notice">
                            <strong>Error:</strong> <?php echo htmlspecialchars($ga_error); ?>
                        </div>
                    <?php endif; ?>

                    <?php if ($ga_data): ?>
                        <div class="ga-data-grid">
                            <div class="ga-data-card">
                                <h3>Sessions</h3>
                                <p class="ga-data-value"><?php echo htmlspecialchars($ga_data['sessions']); ?></p>
                            </div>
                            <div class="ga-data-card">
                                <h3>Users</h3>
                                <p class="ga-data-value"><?php echo htmlspecialchars($ga_data['users']); ?></p>
                            </div>
                            <div class="ga-data-card">
                                <h3>Page Views</h3>
                                <p class="ga-data-value"><?php echo htmlspecialchars($ga_data['page_views']); ?></p>
                            </div>
                            <div class="ga-data-card">
                                <h3>Bounce Rate</h3>
                                <p class="ga-data-value"><?php echo htmlspecialchars($ga_data['bounce_rate']); ?></p>
                            </div>
                        </div>
                    <?php else: ?>
                         <div class="ga-loading-notice">
                            Attempting to fetch live data from Google Analytics... If this message persists, please check your Property ID or try reconnecting.
                        </div>
                    <?php endif; ?>
                </section>
            <?php endif; ?>
        <?php endif; ?>

        <section class="chart-section">
            <div class="chart-container">
                <h2 class="chart-title">Sessions Over Time (Sample)</h2>
                <div class="chart">
                    <?php
                    $max_value = max($chart_data['values']);
                    foreach ($chart_data['values'] as $index => $value):
                        $height_percentage = ($value / $max_value) * 100;
                    ?>
                    <div class="chart-bar-wrapper">
                        <div class="chart-bar" style="height: <?php echo $height_percentage; ?>%;"></div>
                        <span class="chart-label"><?php echo $chart_data['labels'][$index]; ?></span>
                    </div>
                    <?php endforeach; ?>
                </div>
            </div>
        </section>

    </main>

</body>
</html>