#!/usr/bin/env php
<?php
/**
 * Migration: Add closed_at column to tickets table
 *
 * Adds a dedicated timestamp for when tickets are closed,
 * so avg resolution time isn't inflated by post-close edits.
 *
 * Usage: php scripts/add_closed_at_column.php
 */

require_once dirname(__DIR__) . '/config/config.php';

$conn = new mysqli(
    $GLOBALS['config']['DB_HOST'],
    $GLOBALS['config']['DB_USER'],
    $GLOBALS['config']['DB_PASS'],
    $GLOBALS['config']['DB_NAME']
);

if ($conn->connect_error) {
    die("Database connection failed: " . $conn->connect_error . "\n");
}

echo "Adding closed_at column to tickets table...\n";

// Add the column if it doesn't exist
$result = $conn->query("SHOW COLUMNS FROM tickets LIKE 'closed_at'");
if ($result->num_rows > 0) {
    echo "Column 'closed_at' already exists, skipping ALTER TABLE.\n";
} else {
    $sql = "ALTER TABLE tickets ADD COLUMN closed_at TIMESTAMP NULL DEFAULT NULL AFTER updated_at";
    if ($conn->query($sql)) {
        echo "Column added successfully.\n";
    } else {
        die("Failed to add column: " . $conn->error . "\n");
    }

    // Add index for stats queries
    $conn->query("CREATE INDEX idx_tickets_closed_at ON tickets (closed_at)");
    echo "Index created.\n";
}

// Backfill: For existing closed tickets, use the audit log to find when they were closed
echo "\nBackfilling closed_at from audit log...\n";

$sql = "UPDATE tickets t
        JOIN (
            SELECT entity_id as ticket_id, MIN(created_at) as first_closed
            FROM audit_log
            WHERE entity_type = 'ticket'
            AND action_type = 'update'
            AND details LIKE '%\"status\":\"Closed\"%'
            GROUP BY entity_id
        ) al ON t.ticket_id = al.ticket_id
        SET t.closed_at = al.first_closed
        WHERE t.status = 'Closed' AND t.closed_at IS NULL";

$result = $conn->query($sql);
$backfilled = $conn->affected_rows;
echo "Backfilled $backfilled tickets from audit log.\n";

// For any remaining closed tickets without audit log entries, use updated_at as fallback
$sql = "UPDATE tickets SET closed_at = updated_at WHERE status = 'Closed' AND closed_at IS NULL";
$conn->query($sql);
$fallback = $conn->affected_rows;
if ($fallback > 0) {
    echo "Used updated_at as fallback for $fallback tickets without audit log entries.\n";
}

echo "\nMigration complete!\n";
$conn->close();