<?php
require_once 'db/config.php';
$db = db();

echo "<h1>Applying Database Fixes...</h1>";

try {
    // 1. Add columns if missing
    try {
        $db->exec("ALTER TABLE appointments ADD COLUMN start_time DATETIME NULL");
        echo "Added start_time column.<br>";
    } catch (PDOException $e) {
        echo "start_time check: " . $e->getMessage() . "<br>";
    }

    try {
        $db->exec("ALTER TABLE appointments ADD COLUMN end_time DATETIME NULL");
        echo "Added end_time column.<br>";
    } catch (PDOException $e) {
        echo "end_time check: " . $e->getMessage() . "<br>";
    }

    // 2. Migrate data
    // Check if appointment_date exists before trying to use it
    try {
        $stmt = $db->query("SHOW COLUMNS FROM appointments LIKE 'appointment_date'");
        if ($stmt->fetch()) {
            $db->exec("UPDATE appointments SET start_time = appointment_date WHERE start_time IS NULL");
            echo "Migrated data from appointment_date to start_time.<br>";
        } else {
            echo "Column 'appointment_date' does not exist, skipping data migration.<br>";
        }
    } catch (PDOException $e) {
        echo "Data migration check failed: " . $e->getMessage() . "<br>";
    }

    // Populate end_time based on start_time
    try {
        $db->exec("UPDATE appointments SET end_time = DATE_ADD(start_time, INTERVAL 30 MINUTE) WHERE end_time IS NULL AND start_time IS NOT NULL");
        echo "Populated end_time based on start_time.<br>";
    } catch (PDOException $e) {
        echo "Could not populate end_time: " . $e->getMessage() . "<br>";
    }

    // 3. Set NOT NULL constraint
    try {
        // Only if start_time has values (or table is empty)
        $db->exec("ALTER TABLE appointments MODIFY COLUMN start_time DATETIME NOT NULL");
        echo "Set start_time to NOT NULL.<br>";
    } catch (PDOException $e) {
        echo "Could not set start_time to NOT NULL (maybe some rows are NULL?): " . $e->getMessage() . "<br>";
    }
    
    try {
        $db->exec("ALTER TABLE appointments MODIFY COLUMN end_time DATETIME NOT NULL");
        echo "Set end_time to NOT NULL.<br>";
    } catch (PDOException $e) {
        echo "Could not set end_time to NOT NULL: " . $e->getMessage() . "<br>";
    }
    
    // 4. Ensure other columns exist (like nurse_id, visit_type, etc. from previous migrations)
    try {
        $db->exec("ALTER TABLE appointments ADD COLUMN nurse_id INT NULL");
    } catch (Exception $e) {}
    try {
        $db->exec("ALTER TABLE appointments ADD COLUMN visit_type ENUM('Clinic', 'Home') DEFAULT 'Clinic'");
    } catch (Exception $e) {}
    try {
        $db->exec("ALTER TABLE appointments ADD COLUMN address TEXT NULL");
    } catch (Exception $e) {}
    
    echo "<h2>Fix completed successfully.</h2>";
    echo "<p><a href='dashboard.php' class='btn btn-primary'>Go to Dashboard</a></p>";

} catch (PDOException $e) {
    echo "<h2>Fatal Error during fix:</h2> " . $e->getMessage();
}