<?php
/**
 * Builds the per-gallery CSS: custom properties for every setting and the
 * responsive column counts.
 *
 * The static look and behavior lives in assets/css/frontend.css; this file only
 * supplies values. Everything interpolated here has already been through
 * EquaFrame_Settings::sanitize() (ints, enum members, hex colors).
 */

defined( 'ABSPATH' ) || exit;

class EquaFrame_CSS {

	public static function hex_to_rgb( $hex ) {
		$hex = ltrim( (string) $hex, '#' );
		if ( 3 === strlen( $hex ) ) {
			$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
		}
		if ( 6 !== strlen( $hex ) || ! ctype_xdigit( $hex ) ) {
			return array( 0, 0, 0 );
		}
		return array( hexdec( substr( $hex, 0, 2 ) ), hexdec( substr( $hex, 2, 2 ) ), hexdec( substr( $hex, 4, 2 ) ) );
	}

	private static function rgba( $hex, $opacity_percent ) {
		list( $r, $g, $b ) = self::hex_to_rgb( $hex );
		return sprintf( 'rgba(%d,%d,%d,%s)', $r, $g, $b, round( $opacity_percent / 100, 3 ) );
	}

	/**
	 * Fluid length: equals $max at REF_WIDTH and above, shrinks with the viewport, never below $min.
	 */
	private static function fluid( $max, $min ) {
		$min = min( $min, $max );
		$vw  = round( $max / EquaFrame_Settings::REF_WIDTH * 100, 3 );
		return sprintf( 'clamp(%dpx,%svw,%dpx)', $min, $vw, $max );
	}

	/**
	 * @param int   $id Gallery ID.
	 * @param array $s  Sanitized settings.
	 */
	public static function build( $id, $s ) {
		$id    = (int) $id;
		$scope = '.eqfr-gallery.eqfr-gallery-' . $id;
		$vars  = array();

		// Size and alignment.
		$vars[] = '--eqfr-max:' . (int) $s['max_width'] . $s['max_width_unit'];
		$vars[] = '--eqfr-gap:' . self::fluid( (int) $s['gap'], (int) $s['gap_min'] );
		$vars[] = '--eqfr-cols:' . (int) $s['cols_desktop'];
		$vars[] = '--eqfr-ratio:' . $s['grid_ratio'];
		$vars[] = '--eqfr-row:' . self::fluid( (int) $s['mosaic_row'], (int) round( $s['mosaic_row'] * 0.6 ) );

		// Look.
		$vars[] = '--eqfr-radius:' . ( $s['radius_on'] ? (int) $s['radius'] . $s['radius_unit'] : '0' );
		$vars[] = '--eqfr-border:' . ( $s['border_on'] ? sprintf( '%dpx %s %s', $s['border_width'], $s['border_style'], $s['border_color'] ) : 'none' );
		$vars[] = '--eqfr-shadow:' . ( $s['shadow_on'] ? sprintf( '%dpx %dpx %dpx %dpx %s', $s['shadow_x'], $s['shadow_y'], $s['shadow_blur'], $s['shadow_spread'], self::rgba( $s['shadow_color'], $s['shadow_opacity'] ) ) : 'none' );
		$vars[] = '--eqfr-zoom:' . ( $s['zoom_on'] ? round( 1 + $s['zoom_amount'] / 100, 3 ) : '1' );
		$vars[] = '--eqfr-ctl-color:' . $s['ctl_color'];
		$vars[] = '--eqfr-ctl-bg:' . $s['ctl_bg'];
		// The close button follows the shared button colors unless it has its own.
		$vars[] = '--eqfr-close-color:' . ( '' !== $s['lb_close_color'] ? $s['lb_close_color'] : 'var(--eqfr-ctl-color)' );
		$vars[] = '--eqfr-close-bg:' . ( '' !== $s['lb_close_bg'] ? $s['lb_close_bg'] : 'var(--eqfr-ctl-bg)' );
		$vars[] = '--eqfr-close-border:' . ( '' !== $s['lb_close_border'] ? '2px solid ' . $s['lb_close_border'] : '0' );
		$vars[] = '--eqfr-cap-color:' . $s['cap_color'];
		$vars[] = '--eqfr-cap-bg:' . self::rgba( $s['cap_bg'], $s['cap_bg_opacity'] );
		$vars[] = '--eqfr-lb-bg:' . ( $s['lb_backdrop'] ? self::rgba( $s['lb_backdrop_color'], $s['lb_backdrop_opacity'] ) : 'transparent' );

		// Slideshow.
		$vars[] = '--eqfr-ss-ratio:' . $s['ss_ratio'];
		$vars[] = '--eqfr-ss-fit:' . $s['ss_fit'];
		$vars[] = '--eqfr-strip-visible:' . (int) $s['ss_strip_visible'];

		$css = $scope . '{' . implode( ';', $vars ) . ';';
		$css .= 'margin-left:' . ( 'left' === $s['align'] ? '0' : 'auto' ) . ';';
		$css .= 'margin-right:' . ( 'right' === $s['align'] ? '0' : 'auto' ) . ';';
		if ( '' !== $s['bg_color'] ) {
			$css .= 'background-color:' . $s['bg_color'] . ';';
		}
		if ( $s['outer_pad'] ) {
			$css .= 'padding:var(--eqfr-gap);';
		}
		$css .= '}';

		// Responsive columns, filmstrip count and the mosaic collapse.
		$breakpoints = array(
			EquaFrame_Settings::BP_TABLET => array( (int) $s['cols_tablet'], (int) $s['ss_strip_visible'] ),
			EquaFrame_Settings::BP_MOBILE => array( (int) $s['cols_mobile'], (int) $s['ss_strip_visible_mobile'] ),
		);
		$mosaic = $scope . '.eqfr-layout-mosaic .eqfr-item:nth-child(n){grid-column:auto;grid-row:auto}';

		if ( (int) $s['cols_desktop'] < 2 ) {
			$css .= $mosaic;
		}
		foreach ( $breakpoints as $max => $values ) {
			$css .= '@media (max-width:' . $max . 'px){' . $scope . '{--eqfr-cols:' . $values[0] . ';--eqfr-strip-visible:' . $values[1] . '}';
			if ( $values[0] < 2 ) {
				$css .= $mosaic;
			}
			$css .= '}';
		}

		return $css;
	}
}