<?php
namespace App\Helpers;

/**
 * Class EscPosPrinter
 * Enterprise Thermal Printer ESC/POS Command Builder (Queue Tickets & Tax Invoices)
 *
 * @package App\Helpers
 */
class EscPosPrinter
{
    private string $buffer = "";
    private string $ip;
    private int $port;

    // ESC/POS Command Constants
    const ESC = "\x1B";
    const GS = "\x1D";
    const LF = "\x0A";

    public function __construct(string $ip = '192.168.1.200', int $port = 9100)
    {
        $this->ip = $ip;
        $this->port = $port;
        $this->init();
    }

    /**
     * Initialize Printer
     */
    public function init(): self
    {
        $this->buffer .= self::ESC . "@"; // Reset
        return $this;
    }

    /**
     * Set text alignment
     * @param string $align 'left' | 'center' | 'right'
     */
    public function setAlign(string $align): self
    {
        $val = 0;
        if ($align === 'center') $val = 1;
        if ($align === 'right')  $val = 2;
        $this->buffer .= self::ESC . "a" . chr($val);
        return $this;
    }

    /**
     * Set text size
     * @param int $width 1-8
     * @param int $height 1-8
     */
    public function setSize(int $width = 1, int $height = 1): self
    {
        $w = ($width - 1) << 4;
        $h = ($height - 1);
        $this->buffer .= self::GS . "!" . chr($w | $h);
        return $this;
    }

    /**
     * Set font emphasis (Bold)
     */
    public function setBold(bool $enabled = true): self
    {
        $this->buffer .= self::ESC . "E" . chr($enabled ? 1 : 0);
        return $this;
    }

    /**
     * Print text line with Line Feed
     */
    public function text(string $text): self
    {
        // ในระบบ Thermal Printer ไทยมักใช้ TIS-620 หรือ CP874
        // แปลง UTF-8 เป็น CP874
        $converted = @iconv('UTF-8', 'CP874//IGNORE', $text);
        $this->buffer .= ($converted !== false ? $converted : $text) . self::LF;
        return $this;
    }

    /**
     * Print Horizontal Line separator (80mm = 48 chars)
     */
    public function line(): self
    {
        $this->text(str_repeat('-', 48));
        return $this;
    }

    /**
     * Feed paper and cut
     */
    public function cut(): self
    {
        $this->buffer .= self::LF . self::LF . self::LF;
        $this->buffer .= self::GS . "V" . chr(66) . chr(0); // Partial cut
        return $this;
    }

    /**
     * Get RAW buffer for WebUSB / Browser Print
     */
    public function getBuffer(): string
    {
        return $this->buffer;
    }

    /**
     * Get Base64 encoded buffer for JSON API transfer to POS Frontend
     */
    public function getBase64Buffer(): string
    {
        return base64_encode($this->buffer);
    }

    /**
     * Send command directly to Network LAN Printer via Socket
     * @return bool
     */
    public function sendToPrinter(): bool
    {
        $fp = @fsockopen($this->ip, $this->port, $errno, $errstr, 2.0);
        if (!$fp) {
            error_log("ESC/POS Printer Connect Failed ({$this->ip}:{$this->port}) - {$errstr} ({$errno})");
            return false;
        }
        fwrite($fp, $this->buffer);
        fclose($fp);
        return true;
    }

    /**
     * Build Queue Ticket Buffer (ใบคิวสำหรับผู้ป่วย)
     */
    public static function buildQueueTicket(array $queueData): string
    {
        $printer = new self();
        $printer->setAlign('center')
                ->setSize(2, 2)->setBold(true)->text("ใบคิวนวดแผนไทย")
                ->setSize(1, 1)->setBold(false)->text($queueData['branch_name'] ?? "TTMQMS Center")
                ->line()
                ->setSize(3, 3)->setBold(true)->text($queueData['queue_no'])
                ->setSize(1, 1)->setBold(false)->text("ประเภทคิว: " . ($queueData['priority'] ?? 'Normal'))
                ->line()
                ->setAlign('left')
                ->text("ผู้รับบริการ: " . ($queueData['patient_name'] ?? '-'))
                ->text("บริการ: " . ($queueData['service_name'] ?? '-'))
                ->text("หมอนวด: " . ($queueData['therapist_name'] ?? 'รอจัดสรร (AI Queue)'))
                ->text("ห้องนวด: " . ($queueData['room_no'] ?? '-'))
                ->line()
                ->setAlign('center')
                ->text("เวลาออกคิว: " . ($queueData['checkin_time'] ?? date('Y-m-d H:i:s')))
                ->text("โปรดรอเรียกคิวที่หน้าจอ TV Display")
                ->text("*** ขอบพระคุณที่ใช้บริการ ***")
                ->cut();

        return $printer->getBase64Buffer();
    }
}