<?php
/**
 * Small, dependency-free PDF writer used by Toolkit modules
 * (invoices, packing slips, future gift card certificates).
 *
 * - Coordinates are in points (1/72 in) from the TOP-LEFT of the page.
 * - Fonts: the PDF built-in Helvetica / Helvetica-Bold (no embedding needed).
 *   Text is converted to Windows-1252, which covers English and Western
 *   European languages; other characters print as "?".
 * - Images: JPEG directly; PNG/GIF/WebP are flattened onto white and
 *   converted to JPEG with GD when it's available.
 *
 * @package BYLTCommerce
 */

defined( 'ABSPATH' ) || exit;

class Bylt_Pdf {

	/** @var array|null */
	private static $metrics = null;

	private $w;
	private $h;

	/** @var string[] Content stream per page. */
	private $pages = array();

	/** @var array[] Image XObjects: name => [data, w, h, colorspace, bpc, decode]. */
	private $images = array();

	/** @var array Image cache keyed by source hash. */
	private $image_keys = array();

	private $page = -1;
	private $font = 'F1';
	private $size = 10.0;

	/** @var string */
	private $title = '';

	public function __construct( $paper = 'letter' ) {
		if ( 'a4' === $paper ) {
			$this->w = 595.28;
			$this->h = 841.89;
		} else {
			$this->w = 612.0;
			$this->h = 792.0;
		}
		if ( null === self::$metrics ) {
			self::$metrics = include __DIR__ . '/pdf/font-metrics.php';
		}
	}

	public function width() {
		return $this->w;
	}

	public function height() {
		return $this->h;
	}

	public function set_title( $title ) {
		$this->title = (string) $title;
	}

	/* ---------------------------------------------------------------------
	 * Pages
	 * ------------------------------------------------------------------- */

	public function add_page() {
		$this->pages[] = '';
		$this->page    = count( $this->pages ) - 1;
		return $this->page;
	}

	public function page_count() {
		return count( $this->pages );
	}

	public function current_page() {
		return $this->page;
	}

	/** Go back to an earlier page (e.g. to add "Page 1 of 3" footers). */
	public function set_page( $index ) {
		if ( isset( $this->pages[ $index ] ) ) {
			$this->page = $index;
		}
	}

	private function out( $ops ) {
		if ( $this->page < 0 ) {
			$this->add_page();
		}
		$this->pages[ $this->page ] .= $ops . "\n";
	}

	/* ---------------------------------------------------------------------
	 * Text
	 * ------------------------------------------------------------------- */

	public function set_font( $bold = false, $size = 10 ) {
		$this->font = $bold ? 'F2' : 'F1';
		$this->size = (float) $size;
	}

	public function font_size() {
		return $this->size;
	}

	/**
	 * UTF-8 → Windows-1252.
	 */
	public static function encode( $text ) {
		$text = (string) $text;
		$text = str_replace( array( "\xC2\xA0", "\xE2\x80\xAF" ), ' ', $text ); // Non-breaking spaces.
		if ( function_exists( 'iconv' ) ) {
			$out = @iconv( 'UTF-8', 'CP1252//TRANSLIT//IGNORE', $text ); // phpcs:ignore WordPress.PHP.NoSilencedErrors
			if ( false !== $out ) {
				return $out;
			}
		}
		if ( function_exists( 'mb_convert_encoding' ) ) {
			return mb_convert_encoding( $text, 'Windows-1252', 'UTF-8' );
		}
		return preg_replace( '/[^\x20-\x7E]/', '?', $text );
	}

	/** Width in points of UTF-8 text in the current (or given) font. */
	public function text_width( $text, $bold = null, $size = null ) {
		$font  = null === $bold ? $this->font : ( $bold ? 'F2' : 'F1' );
		$size  = null === $size ? $this->size : (float) $size;
		$bytes = self::encode( $text );
		$units = 0;
		$len   = strlen( $bytes );
		for ( $i = 0; $i < $len; $i++ ) {
			$units += self::$metrics[ $font ][ ord( $bytes[ $i ] ) ];
		}
		return $units * $size / 1000;
	}

	/**
	 * Break text into lines that fit $max_width in the current font.
	 *
	 * @return string[]
	 */
	public function wrap( $text, $max_width ) {
		$lines = array();
		foreach ( preg_split( "/\r\n|\r|\n/", (string) $text ) as $para ) {
			$words = preg_split( '/ +/', trim( $para ) );
			$line  = '';
			foreach ( $words as $word ) {
				$try = '' === $line ? $word : $line . ' ' . $word;
				if ( $this->text_width( $try ) <= $max_width ) {
					$line = $try;
					continue;
				}
				if ( '' !== $line ) {
					$lines[] = $line;
				}
				// A single word longer than the line: hard-break it.
				while ( $this->text_width( $word ) > $max_width && strlen( $word ) > 1 ) {
					$cut = strlen( $word );
					while ( $cut > 1 && $this->text_width( substr( $word, 0, $cut ) ) > $max_width ) {
						--$cut;
					}
					$lines[] = substr( $word, 0, $cut );
					$word    = substr( $word, $cut );
				}
				$line = $word;
			}
			$lines[] = $line;
		}
		return $lines;
	}

	private static function esc( $bytes ) {
		return str_replace( array( '\\', '(', ')', "\r" ), array( '\\\\', '\\(', '\\)', '\\r' ), $bytes );
	}

	private static function rgb( $hex ) {
		$hex = ltrim( (string) $hex, '#' );
		if ( 3 === strlen( $hex ) ) {
			$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
		}
		if ( ! preg_match( '/^[0-9a-fA-F]{6}$/', $hex ) ) {
			$hex = '000000';
		}
		return sprintf( '%.3F %.3F %.3F', hexdec( substr( $hex, 0, 2 ) ) / 255, hexdec( substr( $hex, 2, 2 ) ) / 255, hexdec( substr( $hex, 4, 2 ) ) / 255 );
	}

	/**
	 * Draw one line of text. $y is the TOP of the line box.
	 *
	 * @param array $opts color (hex), align (left|right|center), width (box width for right/center).
	 */
	public function text( $x, $y, $text, $opts = array() ) {
		$opts = array_merge(
			array(
				'color' => '#1d2327',
				'align' => 'left',
				'width' => 0,
			),
			$opts
		);

		if ( 'right' === $opts['align'] ) {
			$x += $opts['width'] - $this->text_width( $text );
		} elseif ( 'center' === $opts['align'] ) {
			$x += ( $opts['width'] - $this->text_width( $text ) ) / 2;
		}

		$baseline = $y + $this->size * 0.8;
		$this->out(
			sprintf(
				'BT /%s %.2F Tf %s rg %.2F %.2F Td (%s) Tj ET',
				$this->font,
				$this->size,
				self::rgb( $opts['color'] ),
				$x,
				$this->h - $baseline,
				self::esc( self::encode( $text ) )
			)
		);
	}

	/**
	 * Wrapped paragraph. Returns the height used.
	 */
	public function paragraph( $x, $y, $width, $text, $opts = array(), $line_height = 1.3 ) {
		$lh    = $this->size * $line_height;
		$lines = $this->wrap( $text, $width );
		foreach ( $lines as $i => $line ) {
			$this->text( $x, $y + $i * $lh, $line, array_merge( $opts, array( 'width' => $width ) ) );
		}
		return count( $lines ) * $lh;
	}

	/* ---------------------------------------------------------------------
	 * Shapes
	 * ------------------------------------------------------------------- */

	public function line( $x1, $y1, $x2, $y2, $width = 0.5, $color = '#c3c4c7' ) {
		$this->out( sprintf( 'q %s RG %.2F w %.2F %.2F m %.2F %.2F l S Q', self::rgb( $color ), $width, $x1, $this->h - $y1, $x2, $this->h - $y2 ) );
	}

	public function rect( $x, $y, $w, $h, $fill = '#f0f0f1', $stroke = null, $stroke_width = 0.5 ) {
		$ops = 'q ';
		if ( $fill ) {
			$ops .= self::rgb( $fill ) . ' rg ';
		}
		if ( $stroke ) {
			$ops .= self::rgb( $stroke ) . ' RG ' . sprintf( '%.2F w ', $stroke_width );
		}
		$op   = $fill && $stroke ? 'B' : ( $fill ? 'f' : 'S' );
		$ops .= sprintf( '%.2F %.2F %.2F %.2F re %s Q', $x, $this->h - $y - $h, $w, $h, $op );
		$this->out( $ops );
	}

	/* ---------------------------------------------------------------------
	 * Images
	 * ------------------------------------------------------------------- */

	/**
	 * Draw an image scaled to fit inside $max_w × $max_h (top-left at $x,$y).
	 *
	 * @param string $source File path or raw image bytes.
	 * @return array|false [width, height] drawn, or false if the image can't be used.
	 */
	public function image( $source, $x, $y, $max_w, $max_h ) {
		$name = $this->load_image( $source );
		if ( ! $name ) {
			return false;
		}
		list( , $iw, $ih ) = $this->images[ $name ];
		$scale             = min( $max_w / $iw, $max_h / $ih );
		$w                 = $iw * $scale;
		$h                 = $ih * $scale;
		$this->out( sprintf( 'q %.2F 0 0 %.2F %.2F %.2F cm /%s Do Q', $w, $h, $x, $this->h - $y - $h, $name ) );
		return array( $w, $h );
	}

	private function load_image( $source ) {
		if ( ! is_string( $source ) || '' === $source ) {
			return false;
		}
		$bytes = ( strlen( $source ) < 4096 && @is_file( $source ) ) ? file_get_contents( $source ) : $source; // phpcs:ignore
		if ( ! $bytes ) {
			return false;
		}

		$key = md5( $bytes );
		if ( isset( $this->image_keys[ $key ] ) ) {
			return $this->image_keys[ $key ];
		}

		$info = @getimagesizefromstring( $bytes ); // phpcs:ignore WordPress.PHP.NoSilencedErrors
		if ( ! $info ) {
			return false;
		}

		if ( IMAGETYPE_JPEG !== $info[2] ) {
			$bytes = self::to_jpeg( $bytes );
			if ( ! $bytes ) {
				return false;
			}
			$info = getimagesizefromstring( $bytes );
		}

		$channels = isset( $info['channels'] ) ? (int) $info['channels'] : 3;
		$cs       = 1 === $channels ? 'DeviceGray' : ( 4 === $channels ? 'DeviceCMYK' : 'DeviceRGB' );

		$name                     = 'I' . ( count( $this->images ) + 1 );
		$this->images[ $name ]    = array( $bytes, (int) $info[0], (int) $info[1], $cs, 4 === $channels );
		$this->image_keys[ $key ] = $name;
		return $name;
	}

	private static function to_jpeg( $bytes ) {
		if ( ! function_exists( 'imagecreatefromstring' ) ) {
			return false;
		}
		$src = @imagecreatefromstring( $bytes ); // phpcs:ignore WordPress.PHP.NoSilencedErrors
		if ( ! $src ) {
			return false;
		}
		$w   = imagesx( $src );
		$h   = imagesy( $src );
		$dst = imagecreatetruecolor( $w, $h );
		imagefill( $dst, 0, 0, imagecolorallocate( $dst, 255, 255, 255 ) );
		imagealphablending( $dst, true );
		imagecopy( $dst, $src, 0, 0, 0, 0, $w, $h );
		ob_start();
		imagejpeg( $dst, null, 92 );
		$out = ob_get_clean();
		imagedestroy( $src );
		imagedestroy( $dst );
		return $out;
	}

	/* ---------------------------------------------------------------------
	 * Output
	 * ------------------------------------------------------------------- */

	/** @return string The PDF file contents. */
	public function output() {
		if ( ! $this->pages ) {
			$this->add_page();
		}

		$objects = array(); // index (1-based) => body.
		$n       = 2;        // 1 = catalog, 2 = pages.

		$font_ids = array();
		foreach ( array( 'F1' => 'Helvetica', 'F2' => 'Helvetica-Bold' ) as $key => $base ) {
			$font_ids[ $key ]  = ++$n;
			$objects[ $n ]     = "<< /Type /Font /Subtype /Type1 /BaseFont /{$base} /Encoding /WinAnsiEncoding >>";
		}

		$image_ids = array();
		foreach ( $this->images as $name => $img ) {
			list( $data, $iw, $ih, $cs, $invert ) = $img;
			$image_ids[ $name ] = ++$n;
			$decode             = $invert ? ' /Decode [1 0 1 0 1 0 1 0]' : '';
			$objects[ $n ]      = array(
				"<< /Type /XObject /Subtype /Image /Width {$iw} /Height {$ih} /ColorSpace /{$cs} /BitsPerComponent 8 /Filter /DCTDecode{$decode} /Length " . strlen( $data ) . ' >>',
				$data,
			);
		}

		$resources = '<< /Font << ';
		foreach ( $font_ids as $key => $id ) {
			$resources .= "/{$key} {$id} 0 R ";
		}
		$resources .= '>>';
		if ( $image_ids ) {
			$resources .= ' /XObject << ';
			foreach ( $image_ids as $name => $id ) {
				$resources .= "/{$name} {$id} 0 R ";
			}
			$resources .= '>>';
		}
		$resources .= ' >>';

		$kids     = array();
		$compress = function_exists( 'gzcompress' );
		foreach ( $this->pages as $content ) {
			$page_id    = ++$n;
			$content_id = ++$n;
			$kids[]     = "{$page_id} 0 R";

			$objects[ $page_id ] = sprintf(
				'<< /Type /Page /Parent 2 0 R /MediaBox [0 0 %.2F %.2F] /Resources %s /Contents %d 0 R >>',
				$this->w,
				$this->h,
				$resources,
				$content_id
			);

			$stream                 = $compress ? gzcompress( $content ) : $content;
			$objects[ $content_id ] = array(
				'<< ' . ( $compress ? '/Filter /FlateDecode ' : '' ) . '/Length ' . strlen( $stream ) . ' >>',
				$stream,
			);
		}

		$objects[1] = '<< /Type /Catalog /Pages 2 0 R >>';
		$objects[2] = '<< /Type /Pages /Kids [' . implode( ' ', $kids ) . '] /Count ' . count( $kids ) . ' >>';

		$info_id             = ++$n;
		$objects[ $info_id ] = '<< /Producer (' . self::esc( 'BYLTCommerce Toolkit' ) . ')' . ( $this->title ? ' /Title (' . self::esc( self::encode( $this->title ) ) . ')' : '' ) . ' /CreationDate (D:' . gmdate( 'YmdHis' ) . 'Z) >>';

		ksort( $objects );

		$pdf     = "%PDF-1.4\n%\xE2\xE3\xCF\xD3\n";
		$offsets = array();
		foreach ( $objects as $id => $body ) {
			$offsets[ $id ] = strlen( $pdf );
			if ( is_array( $body ) ) {
				$pdf .= "{$id} 0 obj\n{$body[0]}\nstream\n{$body[1]}\nendstream\nendobj\n";
			} else {
				$pdf .= "{$id} 0 obj\n{$body}\nendobj\n";
			}
		}

		$xref = strlen( $pdf );
		$pdf .= "xref\n0 " . ( $n + 1 ) . "\n0000000000 65535 f \n";
		for ( $i = 1; $i <= $n; $i++ ) {
			$pdf .= sprintf( "%010d 00000 n \n", $offsets[ $i ] );
		}
		$pdf .= "trailer\n<< /Size " . ( $n + 1 ) . " /Root 1 0 R /Info {$info_id} 0 R >>\nstartxref\n{$xref}\n%%EOF";

		return $pdf;
	}
}