<?php
declare(strict_types=1);

function seoScheme(): string
{
    return (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') ? 'https' : 'http';
}

function seoHost(): string
{
    return $_SERVER['HTTP_HOST'] ?? 'localhost';
}

function seoBasePath(): string
{
    $scriptName = str_replace('\\', '/', $_SERVER['SCRIPT_NAME'] ?? '/index.php');
    $basePath = rtrim(str_replace('/' . basename($scriptName), '', $scriptName), '/');
    return $basePath === '' ? '' : $basePath;
}

function seoSiteUrl(): string
{
    return seoScheme() . '://' . seoHost() . seoBasePath();
}

function seoCurrentUrl(): string
{
    $requestUri = $_SERVER['REQUEST_URI'] ?? '/';
    return seoScheme() . '://' . seoHost() . $requestUri;
}

function seoAbsoluteUrl(string $relative): string
{
    $relative = ltrim($relative, '/');
    return seoSiteUrl() . '/' . $relative;
}

function seoEsc(string $value): string
{
    return htmlspecialchars($value, ENT_QUOTES, 'UTF-8');
}

function seoDefaultMeta(array $overrides = []): array
{
    $defaults = [
        'lang' => 'en',
        'lang_code' => 'en',
        'author' => 'Jyotirmoy Saha',
        'owner' => 'Jyotirmoy Saha',
        'robots' => 'index, follow',
        'revisit_after' => '3 days',
        'copyright' => '©Jyotirmoy Saha',
        'language' => 'English',
        'rating' => 'General',
        'identifier_url' => 'https://www.jsaha.in',
        'company_website' => 'https://www.jsaha.in',
        'company_address' => 'Kolkata, West Bengal',
        'title' => 'Jyotirmoy Saha | Software Engineer | IT, Data Science, Blockchain Expert | Professional Portfolio of Jyotirmoy Saha',
        'description' => 'Jyotirmoy Saha - B.Tech Software Engineer specializing in IT, Computer Networks, Data Science, Cryptography, and Blockchain. Delivering expert tech solutions.',
        'keywords' => 'Jyotirmoy Saha, software engineer, full-stack developer, web developer, portfolio, jsaha, Kolkata, IT, data science, blockchain, cryptography',
        'og_image' => seoAbsoluteUrl('assets/images/logo.png'),
        'og_type' => 'website',
        'og_locale' => 'en_US',
        'canonical' => seoCurrentUrl(),
        'current_url' => seoCurrentUrl(),
        'dc_language' => 'EN-US',
    ];

    return array_replace($defaults, $overrides);
}

function seoRenderMeta(array $overrides = []): void
{
    $meta = seoDefaultMeta($overrides);
    ?>
    <meta charset="utf-8">
    <meta content="width=device-width, initial-scale=1.0, user-scalable=1.0, minimum-scale=1.0, maximum-scale=1.0" name="viewport">
    <meta name="langCode" content="<?= seoEsc($meta['lang_code']); ?>">
    <meta name="author" content="<?= seoEsc($meta['author']); ?>">
    <meta name="owner" content="<?= seoEsc($meta['owner']); ?>">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <meta name="robots" content="<?= seoEsc($meta['robots']); ?>">
    <meta name="revisit-after" content="<?= seoEsc($meta['revisit_after']); ?>">
    <meta name="copyright" content="<?= seoEsc($meta['copyright']); ?>">
    <meta name="language" content="<?= seoEsc($meta['language']); ?>">
    <meta name="rating" content="<?= seoEsc($meta['rating']); ?>">
    <meta name="url" content="<?= seoEsc($meta['current_url']); ?>">
    <meta name="identifier-URL" content="<?= seoEsc($meta['identifier_url']); ?>">
    <meta name="title" content="<?= seoEsc($meta['title']); ?>">
    <meta name="keywords" content="<?= seoEsc($meta['keywords']); ?>">
    <meta name="description" content="<?= seoEsc($meta['description']); ?>">

    <meta property="og:site_name" content="<?= seoEsc($meta['title']); ?>">
    <meta property="og:image" content="<?= seoEsc($meta['og_image']); ?>">
    <meta property="og:image:width" content="400">
    <meta property="og:image:height" content="400">
    <meta property="og:type" content="<?= seoEsc($meta['og_type']); ?>">
    <meta property="og:locale" content="<?= seoEsc($meta['og_locale']); ?>">
    <meta property="og:title" content="<?= seoEsc($meta['title']); ?>">
    <meta property="og:description" content="<?= seoEsc($meta['description']); ?>">
    <meta property="og:url" content="<?= seoEsc($meta['current_url']); ?>">

    <meta name="dc.creator" content="<?= seoEsc($meta['author']); ?>">
    <meta name="dc.publisher" content="<?= seoEsc($meta['owner']); ?>">
    <meta name="dc.contributors" content="<?= seoEsc($meta['owner']); ?>">
    <meta name="dc.identifier" content="<?= seoEsc($meta['current_url']); ?>">
    <meta name="dc.source" content="<?= seoEsc($meta['company_website']); ?>">
    <meta name="dc.language" content="<?= seoEsc($meta['dc_language']); ?>">
    <meta name="dc.relation" content="<?= seoEsc($meta['company_website']); ?>">

    <title><?= seoEsc($meta['title']); ?></title>
    <link rel="icon" href="<?= seoEsc($meta['og_image']); ?>" type="image/x-icon" sizes="16x16">
    <link rel="icon" href="<?= seoEsc($meta['og_image']); ?>" type="image/x-icon" sizes="32x32">
    <link rel="icon" href="<?= seoEsc($meta['og_image']); ?>" type="image/x-icon" sizes="48x48">
    <link rel="canonical" href="<?= seoEsc($meta['canonical']); ?>">
    <?php
}