<?php
declare(strict_types=1);

/**
 * Shared footer fragment for Android Cast web consoles and hub.
 *
 * Configure: examples/platform/footer.config.php (see footer.config.example.php).
 * Usage: <?php platform_render_footer(); ?> or platform_render_footer(['use_i18n' => false]);
 *
 * Layout (each row omitted when empty):
 *   [ top — full width ]
 *   [ left | right ]  — main row (copyright defaults on left when left unset)
 *   [ bottom — full width ]
 */

function platform_footer_h(mixed $value): string
{
    return htmlspecialchars((string) $value, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
}

/** @return array<string, mixed> */
function platform_footer_config(): array
{
    static $loaded = null;
    if ($loaded !== null) {
        return $loaded;
    }
    $path = __DIR__ . '/footer.config.php';
    if (!is_file($path)) {
        $path = __DIR__ . '/footer.config.example.php';
    }
    $loaded = require $path;
    return is_array($loaded) ? $loaded : [];
}

/** @param array<string, mixed> $cfg */
function platform_footer_year_end(array $cfg): int
{
    if (array_key_exists('year', $cfg) && $cfg['year'] !== null) {
        return (int) $cfg['year'];
    }

    return (int) date('Y');
}

/**
 * Year label: single year or range (e.g. 2026–2026) when year_start is set.
 *
 * @param array<string, mixed> $cfg
 */
function platform_footer_year_label(array $cfg): string
{
    $end = platform_footer_year_end($cfg);
    $start = isset($cfg['year_start']) ? (int) $cfg['year_start'] : 0;
    if ($start > 0) {
        if (!empty($cfg['year_through_current'])) {
            return $start . ' - current';
        }
        if ($start === $end) {
            return (string) $start;
        }

        return $start . "\u{2013}" . $end;
    }

    return (string) $end;
}

/**
 * Default left line: © holder[, year|year-range].
 *
 * @param array<string, mixed> $cfg
 */
function platform_footer_default_left(array $cfg): string
{
    $symbol = trim((string) ($cfg['copyright_symbol'] ?? "\u{00A9}"));
    $holder = trim((string) ($cfg['holder'] ?? ''));
    $showYear = (bool) ($cfg['show_year'] ?? true);
    $parts = [];
    if ($symbol !== '') {
        $parts[] = $symbol;
    }
    if ($holder !== '') {
        $parts[] = $holder;
    }
    $line = implode(' ', $parts);
    if (!$showYear) {
        return $line;
    }
    $yearLabel = platform_footer_year_label($cfg);
    if ($line === '') {
        return $yearLabel;
    }

    return $line . ', ' . $yearLabel;
}

/**
 * Resolve optional row text (null/empty = omit row). Supports per-render overrides in $opts.
 *
 * @param array<string, mixed> $cfg
 * @param array<string, mixed> $opts
 */
function platform_footer_field(array $cfg, array $opts, string $key): ?string
{
    if (array_key_exists($key, $opts)) {
        $v = $opts[$key];
        if ($v === null || $v === false) {
            return null;
        }
        $t = trim((string) $v);

        return $t === '' ? null : $t;
    }
    if (!array_key_exists($key, $cfg)) {
        return null;
    }
    $v = $cfg[$key];
    if ($v === null || $v === false) {
        return null;
    }
    $t = trim((string) $v);

    return $t === '' ? null : $t;
}

/**
 * @param array<string, mixed> $cfg
 * @param array<string, mixed> $opts
 */
function platform_footer_resolve_left(array $cfg, array $opts): ?string
{
    $custom = platform_footer_field($cfg, $opts, 'left');
    if ($custom !== null) {
        return $custom;
    }
    $built = platform_footer_default_left($cfg);

    return $built === '' ? null : $built;
}

/** @deprecated Use platform_footer_default_left(); kept for scripts/tests. */
function platform_footer_plain_text(array $cfg, int $year): string
{
    $cfg = array_merge($cfg, ['year' => $year]);

    return platform_footer_default_left($cfg);
}

/**
 * @param array{use_i18n?: bool, extra_class?: string, top?: ?string, left?: ?string, right?: ?string, bottom?: ?string} $opts
 */
function platform_render_footer(array $opts = []): void
{
    $cfg = platform_footer_config();
    $top = platform_footer_field($cfg, $opts, 'top');
    $left = platform_footer_resolve_left($cfg, $opts);
    $right = platform_footer_field($cfg, $opts, 'right');
    $bottom = platform_footer_field($cfg, $opts, 'bottom');

    $baseClass = (string) ($opts['extra_class'] ?? ($cfg['footer_class'] ?? 'bottom-bar'));
    $classes = trim($baseClass . ' platform-footer');
    if ($top === null && $bottom === null && $right === null) {
        $classes .= ' platform-footer--single-row';
    }

    $useI18n = $opts['use_i18n'] ?? (bool) ($cfg['use_i18n'] ?? true);
    $i18nKey = (string) ($cfg['i18n_key'] ?? 'footer.copyright');
    $leftUsesDefault = platform_footer_field($cfg, $opts, 'left') === null;
    $yearEnd = platform_footer_year_end($cfg);

    echo '<footer class="' . platform_footer_h($classes) . '">';

    if ($top !== null) {
        echo '<div class="platform-footer__top">' . platform_footer_h($top) . '</div>';
    }

    if ($left !== null || $right !== null) {
        echo '<div class="platform-footer__main">';
        if ($left !== null) {
            echo '<div class="platform-footer__left"';
            if ($useI18n && $i18nKey !== '' && $leftUsesDefault) {
                echo ' data-i18n="' . platform_footer_h($i18nKey) . '"'
                    . ' data-year="' . platform_footer_h(platform_footer_year_label($cfg)) . '"'
                    . ' data-year-end="' . $yearEnd . '"';
            }
            echo '>' . platform_footer_h($left) . '</div>';
        }
        if ($right !== null) {
            echo '<div class="platform-footer__right">' . platform_footer_h($right) . '</div>';
        }
        echo '</div>';
    }

    if ($bottom !== null) {
        echo '<div class="platform-footer__bottom">' . platform_footer_h($bottom) . '</div>';
    }

    echo '</footer>';
}