<?php
/**
 * Generate downloadable invoice PDFs.
 *
 * @package PhemightForms
 */

namespace PhemightForms;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Lightweight PDF output for invoices (no external libraries).
 */
class InvoicePdf {

	/**
	 * Stream a PDF download for an invoice.
	 *
	 * @param array $invoice Invoice row.
	 */
	public static function download( array $invoice ) {
		$slug     = sanitize_file_name( $invoice['slug'] ?? 'invoice' );
		$filename = $slug . '.pdf';

		nocache_headers();
		header( 'Content-Type: application/pdf' );
		header( 'Content-Disposition: attachment; filename="' . $filename . '"' );
		header( 'Content-Length: ' . strlen( self::build( $invoice ) ) );

		echo self::build( $invoice ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
		exit;
	}

	/**
	 * Build PDF binary content.
	 *
	 * @param array $invoice Invoice row.
	 * @return string
	 */
	public static function build( array $invoice ) {
		$lines   = [];
		$lines[] = get_bloginfo( 'name' );
		$lines[] = '';
		$lines[] = 'invoice' === ( $invoice['type'] ?? 'invoice' ) ? __( 'INVOICE', 'phemightforms' ) : __( 'PAYMENT REQUEST', 'phemightforms' );
		$lines[] = $invoice['title'] ?? '';
		$lines[] = '';

		if ( ! empty( $invoice['description'] ) ) {
			$lines[] = $invoice['description'];
			$lines[] = '';
		}

		$lines[] = __( 'Invoice #:', 'phemightforms' ) . ' ' . ( $invoice['id'] ?? '' );
		$lines[] = __( 'Date:', 'phemightforms' ) . ' ' . ( isset( $invoice['created'] ) ? mysql2date( get_option( 'date_format' ), $invoice['created'] ) : '' );

		if ( ! empty( $invoice['due_date'] ) ) {
			$lines[] = __( 'Due date:', 'phemightforms' ) . ' ' . $invoice['due_date'];
		}

		$lines[] = __( 'Status:', 'phemightforms' ) . ' ' . ucfirst( $invoice['status'] ?? 'pending' );
		$lines[] = '';

		if ( ! empty( $invoice['customer_name'] ) || ! empty( $invoice['customer_email'] ) ) {
			$lines[] = __( 'Bill to', 'phemightforms' );
			if ( ! empty( $invoice['customer_name'] ) ) {
				$lines[] = $invoice['customer_name'];
			}
			if ( ! empty( $invoice['customer_email'] ) ) {
				$lines[] = $invoice['customer_email'];
			}
			$lines[] = '';
		}

		if ( ! empty( $invoice['line_items'] ) ) {
			$lines[] = __( 'Items', 'phemightforms' );
			$lines[] = str_repeat( '-', 52 );

			foreach ( preg_split( '/\r\n|\r|\n/', $invoice['line_items'] ) as $line ) {
				$line = trim( $line );
				if ( '' === $line ) {
					continue;
				}
				$parts = array_map( 'trim', explode( '|', $line ) );
				$label = $parts[0];
				$price = isset( $parts[1] ) ? Payments::format( Payments::to_amount( $parts[1] ) ) : '';
				$lines[] = $label . ( $price ? '  ·  ' . $price : '' );
			}

			$lines[] = str_repeat( '-', 52 );
			$lines[] = '';
		}

		$lines[] = __( 'Total due:', 'phemightforms' ) . ' ' . Payments::format( $invoice['amount'] ?? 0 );
		$lines[] = '';
		$lines[] = __( 'Payment page:', 'phemightforms' ) . ' ' . Invoices::url( $invoice['slug'] ?? '' );
		$lines[] = '';
		$lines[] = sprintf(
			/* translators: %s: site name */
			__( 'Generated by PhemightForms on %s', 'phemightforms' ),
			get_bloginfo( 'name' )
		);

		return self::document( $lines );
	}

	/**
	 * Render lines into a single-page PDF.
	 *
	 * @param string[] $lines Text lines.
	 * @return string
	 */
	private static function document( array $lines ) {
		$stream  = "BT\n/F1 11 Tf\n50 780 Td\n14 TL\n";
		$first   = true;

		foreach ( $lines as $line ) {
			$escaped = self::escape( (string) $line );

			if ( $first ) {
				$stream .= '(' . $escaped . ") Tj\n";
				$first   = false;
			} else {
				$stream .= 'T* (' . $escaped . ") Tj\n";
			}
		}

		$stream .= 'ET';
		$len     = strlen( $stream );

		$objects   = [];
		$objects[] = '1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj';
		$objects[] = '2 0 obj << /Type /Pages /Kids [3 0 R] /Count 1 >> endobj';
		$objects[] = '3 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Resources << /Font << /F1 4 0 R >> >> /Contents 5 0 R >> endobj';
		$objects[] = '4 0 obj << /Type /Font /Subtype /Type1 /BaseFont /Helvetica >> endobj';
		$objects[] = '5 0 obj << /Length ' . $len . " >> stream\n" . $stream . "\nendstream endobj";

		$pdf  = "%PDF-1.4\n";
		$offs = [];

		foreach ( $objects as $obj ) {
			$offs[] = strlen( $pdf );
			$pdf   .= $obj . "\n";
		}

		$xref = strlen( $pdf );
		$pdf .= "xref\n0 " . ( count( $objects ) + 1 ) . "\n";
		$pdf .= "0000000000 65535 f \n";

		foreach ( $offs as $off ) {
			$pdf .= str_pad( (string) $off, 10, '0', STR_PAD_LEFT ) . " 00000 n \n";
		}

		$pdf .= 'trailer << /Size ' . ( count( $objects ) + 1 ) . ' /Root 1 0 R >> startxref ' . $xref . "\n%%EOF";

		return $pdf;
	}

	/**
	 * Escape text for PDF string literals.
	 *
	 * @param string $text Raw text.
	 * @return string
	 */
	private static function escape( $text ) {
		$text = wp_strip_all_tags( html_entity_decode( $text, ENT_QUOTES, 'UTF-8' ) );

		if ( function_exists( 'iconv' ) ) {
			$converted = iconv( 'UTF-8', 'ISO-8859-1//TRANSLIT//IGNORE', $text );
			if ( false !== $converted ) {
				$text = $converted;
			}
		}

		return str_replace( [ '\\', '(', ')' ], [ '\\\\', '\\(', '\\)' ], $text );
	}
}