import { Socket } from "node:net";
import type {
  PrintReport,
  SubscriptionCardData,
  TicketData,
} from "../interfaces.js";

// Shared ESC/POS rendering + raw-TCP transport for 80mm thermal printers.
// Rongta RP-series, Cashino, and the many OEM clones all speak ESC/POS over a
// raw TCP socket on port 9100 (the JetDirect/RAW convention) with no auth on the
// print socket — they live on the isolated device VLAN. The BYTE STREAM is
// identical across these clones; what differs is live status reporting (the
// Rongta board serves a decoded status page; the Cashino does not), so status
// stays in each driver while the rendering/transport live here.
// See wiki/entities/rongta-printer.md and wiki/concepts/network-isolation.md.

// --- ESC/POS command bytes ----------------------------------------------------
const ESC = 0x1b;
const GS = 0x1d;
const LF = 0x0a;

const INIT = Buffer.from([ESC, 0x40]); // ESC @  — reset to power-on defaults
const ALIGN_CENTER = Buffer.from([ESC, 0x61, 0x01]); // ESC a 1
const ALIGN_LEFT = Buffer.from([ESC, 0x61, 0x00]); // ESC a 0
const BOLD_ON = Buffer.from([ESC, 0x45, 0x01]); // ESC E 1
const BOLD_OFF = Buffer.from([ESC, 0x45, 0x00]); // ESC E 0
const DOUBLE_ON = Buffer.from([GS, 0x21, 0x11]); // GS ! — double width+height
const DOUBLE_OFF = Buffer.from([GS, 0x21, 0x00]);
const FEED_AND_CUT = Buffer.from([ESC, 0x64, 0x04, GS, 0x56, 0x42, 0x00]); // feed 4, GS V B 0 partial cut

// Select code page 852 (Latin-2) for the character set: ESC t n, n=18 (0x12).
// CP852 carries the Albanian letters we print (ë, ç, …); without it the printer
// would interpret our high bytes as CP437 glyphs. Sent in every print's INIT
// preamble. See wiki/concepts/site-metadata.md (i18n / codepage).
const SELECT_CP852 = Buffer.from([ESC, 0x74, 0x12]);

// Minimal Unicode → CP852 byte map for the characters Albanian text actually uses
// beyond ASCII. Anything not listed is transliterated to an ASCII fallback (below)
// so we never emit a byte that renders as the wrong glyph. Extend as needed.
const CP852: Record<string, number> = {
  ë: 0x89,
  Ë: 0xeb,
  ç: 0x87,
  Ç: 0x80,
  // common Latin-2 extras that may appear in a park name/address:
  ä: 0x84,
  ö: 0x94,
  ü: 0x81,
  é: 0x82,
  á: 0xa0,
  í: 0xa1,
  ó: 0xa2,
  ú: 0xa3,
};
// ASCII transliteration for any char with no CP852 mapping (last-resort, so an
// odd glyph degrades to a readable letter rather than garbage).
const ASCII_FALLBACK: Record<string, string> = {
  ë: "e",
  Ë: "E",
  ç: "c",
  Ç: "C",
  ä: "a",
  ö: "o",
  ü: "u",
  é: "e",
  á: "a",
  í: "i",
  ó: "o",
  ú: "u",
};

/** Encode one line of text to CP852 bytes + a line feed. ASCII (<0x80) passes
 *  through; mapped chars use their CP852 byte; unmapped non-ASCII falls back to an
 *  ASCII letter. Pair with SELECT_CP852 in the print preamble. */
function line(text = ""): Buffer {
  const out: number[] = [];
  for (const ch of text) {
    const code = ch.codePointAt(0) ?? 0;
    const mapped = CP852[ch];
    const fallback = ASCII_FALLBACK[ch];
    if (code < 0x80) {
      out.push(code);
    } else if (mapped !== undefined) {
      out.push(mapped);
    } else if (fallback !== undefined) {
      out.push(...Buffer.from(fallback, "ascii"));
    } else {
      out.push(0x3f); // "?" — unknown char, never a wrong glyph
    }
  }
  out.push(LF);
  return Buffer.from(out);
}

// --- Scannable symbol (printer-generated, no image rendering) -----------------
// The ticket id is the session key (wiki/concepts/ticket-encoding.md). We print it
// as a 1D Code128 barcode so ANY legacy laser barcode scanner the booth might have
// can read it. The barcode is rendered by the printer board from these ESC/POS
// commands — we send the data, the firmware draws the bars (no bitmap, no
// dependency). The same code is printed as large human-readable digits below, so
// the operator can hand-key it if every reader fails.

/** GS k — Code128 1D barcode. Height/width set first, then HRI off, then data. */
function code128(data: string): Buffer {
  // Code128 code set B (printable ASCII) — prefix the data with the {B selector.
  const payload = Buffer.from(`{B${data}`, "ascii");
  return Buffer.concat([
    Buffer.from([GS, 0x68, 0x64]), // GS h 100 — barcode height = 100 dots (taller = tolerant of scan angle)
    Buffer.from([GS, 0x77, 0x03]), // GS w 3  — module width = 3 (wider bars for the short-range "Simple" QR/barcode engine; 13-digit Code128 ≈ 495/576 dots, fits 80mm with quiet zones)
    Buffer.from([GS, 0x48, 0x00]), // GS H 0  — HRI text off (we print the id ourselves)
    // GS k 73 n <data>  — function B form: 73 = Code128, n = data byte length.
    Buffer.from([GS, 0x6b, 0x49, payload.length]),
    payload,
  ]);
}

// --- 2D QR symbol (printer-generated via ESC/POS GS ( k) -----------------------
// A true QR for the SUBSCRIPTION card — the subscriber scans it at the reader (which
// reads QR + 1D barcode) every entry/exit for the coverage period. The board renders
// the QR from these GS ( k commands (no bitmap, no dependency), same approach as
// code128. We also print the code as text below as the hand-key fallback.

/** A QR code via ESC/POS `GS ( k`. `size` = module dot size (1–16; 6 ≈ readable on
 *  80mm at short range). Error-correction level M (15%) — robust to a smudged print. */
function qrCode(data: string, size = 6): Buffer {
  const bytes = Buffer.from(data, "ascii");
  // pL/pH encode the data length + 3 (the cn,fn,m header bytes) for function 180.
  const store = bytes.length + 3;
  const pL = store & 0xff;
  const pH = (store >> 8) & 0xff;
  return Buffer.concat([
    // fn 165: select QR model — 1d 28 6b 04 00 31 41 <model=50(2)> 00
    Buffer.from([GS, 0x28, 0x6b, 0x04, 0x00, 0x31, 0x41, 0x32, 0x00]),
    // fn 167: module size — 1d 28 6b 03 00 31 43 <size>
    Buffer.from([GS, 0x28, 0x6b, 0x03, 0x00, 0x31, 0x43, size]),
    // fn 169: error correction level — 1d 28 6b 03 00 31 45 <49=M>
    Buffer.from([GS, 0x28, 0x6b, 0x03, 0x00, 0x31, 0x45, 0x31]),
    // fn 180: store the symbol data — 1d 28 6b pL pH 31 50 30 <data>
    Buffer.from([GS, 0x28, 0x6b, pL, pH, 0x31, 0x50, 0x30]),
    bytes,
    // fn 181: print the stored symbol — 1d 28 6b 03 00 31 51 30
    Buffer.from([GS, 0x28, 0x6b, 0x03, 0x00, 0x31, 0x51, 0x30]),
  ]);
}

// Ticket/receipt strings — Albanian (the site prints in Albanian for now). Kept in
// one place so a real i18n layer (per-locale tables + a t() helper) can replace this
// later without touching the render functions. See wiki/concepts/site-metadata.md.
const STR = {
  /** NIUS label prefix; printed only when the park has a NIUS. */
  nius: (v: string) => `NIUS: ${v}`,
  /** "Printed at:" — precedes the issue timestamp. */
  issuedAt: (v: string) => `Printuar më: ${v}`,
  /** Subscription-card title. */
  subscription: "ABONIM",
  /** "Holder: <name>" line on the card. */
  holder: (name: string) => `Mbajtësi: ${name}`,
  /** "Valid: <from> – <to>" line on the card. */
  validity: (from: string, to: string) => `Vlen: ${from} – ${to}`,
  phone: (v: string) => `TEL: ${v}`,
} as const;

/** Build the ESC/POS byte stream for a free-form text report (e.g. shift Z-report). */
export function renderReport(report: PrintReport): Buffer {
  return Buffer.concat([
    INIT,
    SELECT_CP852,
    ALIGN_CENTER,
    BOLD_ON,
    line(report.title),
    BOLD_OFF,
    ALIGN_LEFT,
    line(),
    ...report.lines.map((l) => line(l)),
    FEED_AND_CUT,
  ]);
}

/** Render the park-identity header from site metadata. Prints the park name large
 *  (or "PARKING" if unset), then operator / NIUS / address lines that are present.
 *  NIUS and the rest only print when set. Non-ASCII renders via CP852 (see line()). */
function renderHeader(h: TicketData["header"]): Buffer {
  const parts: Buffer[] = [
    ALIGN_CENTER,
    BOLD_ON,
    DOUBLE_ON,
    line(h?.parkName || "PARKING"),
    DOUBLE_OFF,
    BOLD_OFF,
  ];
  if (h?.operatorName) parts.push(line(h.operatorName));
  if (h?.nius) parts.push(line(STR.nius(h.nius)));
  if (h?.address) {
    // Address may be multi-line; print each line centered.
    for (const ln of h.address.split(/\r?\n/))
      if (ln.trim()) parts.push(line(ln.trim()));
  }
  if (h?.phone) parts.push(line(STR.phone(h.phone)));
  return Buffer.concat(parts);
}

/** Build the full ESC/POS byte stream for an entry ticket.
 *  Header (park identity) → 1D Code128 barcode of the ticket id → the id in large
 *  digits → issue time. Code128 is read by ANY legacy 1D barcode scanner the booth
 *  might have; the printed digits are the fallback if every reader fails (operator
 *  hand-keys the all-numeric code). Text is Albanian.
 *  See wiki/concepts/ticket-encoding.md and site-metadata.md. */
export function renderTicket(data: TicketData): Buffer {
  return Buffer.concat([
    INIT,
    SELECT_CP852,
    renderHeader(data.header),
    line(),
    // The scannable barcode + the same code in large human-readable digits.
    code128(data.ticketId),
    line(),
    BOLD_ON,
    DOUBLE_ON,
    line(data.ticketId),
    DOUBLE_OFF,
    BOLD_OFF,
    line(),
    line(STR.issuedAt(data.issuedAt)),
    FEED_AND_CUT,
  ]);
}

/** Build the ESC/POS byte stream for a SUBSCRIPTION CARD: park header → a scannable
 *  QR of the code → the code in text (hand-key fallback) → holder + validity window.
 *  The subscriber keeps this and scans the QR at the reader every entry/exit. */
export function renderSubscriptionCard(data: SubscriptionCardData): Buffer {
  const parts: Buffer[] = [
    INIT,
    SELECT_CP852,
    renderHeader(data.header),
    line(),
    BOLD_ON,
    line(STR.subscription),
    BOLD_OFF,
    line(),
    ALIGN_CENTER,
    qrCode(data.code),
    line(),
    // The code in text, as the fallback if the QR won't scan.
    line(data.code),
    ALIGN_LEFT,
    line(),
  ];
  if (data.holderName) parts.push(line(STR.holder(data.holderName)));
  if (data.validFrom || data.validTo) {
    parts.push(line(STR.validity(data.validFrom ?? "—", data.validTo ?? "—")));
  }
  parts.push(FEED_AND_CUT);
  return Buffer.concat(parts);
}

/** Open a TCP socket, write the bytes, wait for flush, then close. */
export function sendRaw(
  host: string,
  port: number,
  payload: Buffer,
  timeoutMs: number,
): Promise<void> {
  return new Promise((resolve, reject) => {
    const sock = new Socket();
    let settled = false;
    const done = (err?: Error) => {
      if (settled) return;
      settled = true;
      sock.destroy();
      err ? reject(err) : resolve();
    };
    sock.setTimeout(timeoutMs);
    sock.on("timeout", () => done(new Error("timeout")));
    sock.on("error", done);
    sock.connect(port, host, () => {
      sock.write(payload, (err) => (err ? done(err) : done()));
    });
  });
}

/** TCP connect probe — reachability of the raw print socket. The print socket has
 *  no status protocol we rely on, so this is the floor for any ESC/POS printer:
 *  it answers "is the printer reachable", not "is it out of paper". */
export function probe(
  host: string,
  port: number,
  timeoutMs: number,
): Promise<void> {
  return new Promise((resolve, reject) => {
    const sock = new Socket();
    let settled = false;
    const done = (err?: Error) => {
      if (settled) return;
      settled = true;
      sock.destroy();
      err ? reject(err) : resolve();
    };
    sock.setTimeout(timeoutMs);
    sock.on("timeout", () => done(new Error("timeout")));
    sock.on("error", done);
    sock.connect(port, host, () => done());
  });
}

// --- shared driver config fields ----------------------------------------------
// Role + failover are identical across ESC/POS printers; defined here so each
// driver shares them. See wiki/concepts/printer-roles-failover.md.
export type PrinterRole = "entry-dispenser" | "booth-receipt";