import fs from 'node:fs';
import os from 'node:os';
import path from 'node:path';
import crypto from 'node:crypto';
import { execFile } from 'node:child_process';
import { createCanvas, loadImage, GlobalFonts } from '@napi-rs/canvas';
import config from './config.js';
import { photoAbsolutePath } from './photos.js';

/**
 * Printing happens on the server, not in the kiosk browser.
 *
 * The badge is drawn to a bitmap here and pushed straight to the printer over the
 * network, so the tablet at the door needs no printer driver, no default printer
 * and no print dialog — and a second kiosk can be added without configuring
 * anything on it.
 *
 * The QL-820NWB prints 696 dots across a 62 mm roll at 300 dpi. That figure is
 * fixed by the printer, so the bitmap is always 696 wide however the badge is
 * laid out; rotation is applied to the finished image, not to the layout.
 */

const DPI = 300;
const DOTS_ACROSS_62MM = 696;
const FONT = 'Liberation Sans, DejaVu Sans, Arial, sans-serif';

const mm = (value) => Math.round((value / 25.4) * DPI);

/** Per-site outcome of the last print, surfaced in the admin console. */
const lastResult = new Map();

export function printerStatus(siteId) {
  return lastResult.get(Number(siteId)) || null;
}

function note(siteId, ok, message) {
  lastResult.set(Number(siteId), { ok, message, at: new Date().toISOString() });
}

export function isConfigured(site) {
  return Boolean(site?.printer_enabled && site?.printer_host);
}

/**
 * brother_ql's media id for the roll that is actually loaded.
 *
 * This is set explicitly rather than inferred from the red styling option. A
 * two-colour job sent to a plain roll is rejected by the printer with "Wrong
 * Roll Type", which gives no clue that a colour checkbox caused it.
 */
export const ROLL_TYPES = {
  '62': '62 mm continuous, black only',
  '62red': '62 mm continuous, black and red (DK-22251)',
};

export function labelFor(site) {
  const label = site?.printer_label;
  return Object.hasOwn(ROLL_TYPES, label) ? label : '62';
}

/** Red ink only exists on the two-colour roll; anywhere else it prints dark grey. */
export function accentWillPrintRed(site) {
  return Boolean(site?.badge_accent) && labelFor(site) === '62red';
}

/* ------------------------------------------------------------ rendering */

function wrapText(ctx, text, maxWidth, maxLines) {
  const words = String(text || '').split(/\s+/).filter(Boolean);
  const lines = [];
  let line = '';
  for (const word of words) {
    const candidate = line ? `${line} ${word}` : word;
    if (ctx.measureText(candidate).width <= maxWidth || !line) {
      line = candidate;
    } else {
      lines.push(line);
      line = word;
      if (lines.length === maxLines - 1) break;
    }
  }
  if (line) lines.push(line);
  return lines.slice(0, maxLines);
}

/**
 * Draws the badge at its designed size in dots. Mirrors the browser badge so the
 * preview and the printed label agree.
 */
async function drawBadge(ctx, widthDots, heightDots, visit, site, accent, startY = null) {
  const unit = Math.min(widthDots, heightDots);
  const pad = Math.round(unit * 0.07);
  const black = '#000000';
  const red = accent ? '#ff0000' : '#000000';

  if (startY !== null) {
    ctx.fillStyle = '#ffffff';
    ctx.fillRect(0, 0, widthDots, heightDots);
  }

  const portrait = heightDots >= widthDots * 1.2;
  const nameSize = Math.max(mm(3.2), Math.round(unit * (portrait ? 0.105 : 0.115)));
  const bodySize = Math.max(mm(2.0), Math.round(unit * (portrait ? 0.055 : 0.062)));

  let photo = null;
  const abs = site.badge_show_photo ? photoAbsolutePath(visit.photo_path) : null;
  if (abs) {
    try {
      photo = await loadImage(abs);
    } catch {
      photo = null;
    }
  }

  const photoSize = photo ? Math.round(unit * (portrait ? 0.52 : 0.5)) : 0;
  let cursorY = startY === null ? pad : startY;
  let textLeft = pad;
  let textWidth = widthDots - pad * 2;

  const paint = startY !== null;

  if (photo) {
    if (portrait) {
      const x = Math.round((widthDots - photoSize) / 2);
      if (paint) ctx.drawImage(photo, x, cursorY, photoSize, photoSize);
      if (paint) {
        ctx.strokeStyle = black;
        ctx.lineWidth = Math.max(2, Math.round(mm(0.3)));
        ctx.strokeRect(x, cursorY, photoSize, photoSize);
      }
      cursorY += photoSize + Math.round(unit * 0.05);
    } else {
      const y = Math.round((heightDots - photoSize) / 2);
      if (paint) {
        ctx.drawImage(photo, pad, y, photoSize, photoSize);
        ctx.strokeStyle = black;
        ctx.lineWidth = Math.max(2, Math.round(mm(0.3)));
        ctx.strokeRect(pad, y, photoSize, photoSize);
      }
      textLeft = pad + photoSize + Math.round(unit * 0.05);
      textWidth = widthDots - textLeft - pad;
    }
  }

  ctx.textBaseline = 'top';
  ctx.textAlign = portrait ? 'center' : 'left';
  const centreX = portrait ? widthDots / 2 : textLeft;

  // Site name, with a rule under it.
  ctx.fillStyle = red;
  ctx.font = `${Math.round(bodySize * 0.8)}px ${FONT}`;
  if (paint) ctx.fillText(`${site.name.toUpperCase()} · VISITOR`, centreX, cursorY, textWidth);
  cursorY += Math.round(bodySize * 0.8 * 1.3);
  if (paint) ctx.fillRect(textLeft, cursorY, textWidth, Math.max(2, Math.round(mm(0.35))));
  cursorY += Math.round(unit * 0.04);

  // Name, wrapped to at most two lines.
  ctx.fillStyle = black;
  ctx.font = `bold ${nameSize}px ${FONT}`;
  const nameLines = wrapText(ctx, `${visit.first_name} ${visit.last_name}`, textWidth, 2);
  for (const line of nameLines) {
    if (paint) ctx.fillText(line, centreX, cursorY, textWidth);
    cursorY += Math.round(nameSize * 1.05);
  }
  cursorY += Math.round(unit * 0.04);

  // Detail rows.
  const timeIn = new Date(visit.signed_in_at);
  const rows = [
    `Visiting ${visit.host_name}`,
    `In at ${timeIn.toLocaleTimeString('en-AU', { hour: '2-digit', minute: '2-digit', hour12: false })} on ${timeIn.toLocaleDateString('en-AU', { day: '2-digit', month: 'short', year: '2-digit' })}`,
  ];

  ctx.font = `${bodySize}px ${FONT}`;
  ctx.fillStyle = black;
  for (const row of rows) {
    for (const line of wrapText(ctx, row, textWidth, 2)) {
      if (paint) ctx.fillText(line, centreX, cursorY, textWidth);
      cursorY += Math.round(bodySize * 1.3);
    }
  }

  // Check status: boxed and in the accent colour when they hold nothing.
  if (visit.check_type === 'NONE') {
    const label = 'No WWCC / VIT';
    ctx.font = `bold ${Math.round(bodySize * 0.95)}px ${FONT}`;
    const w = ctx.measureText(label).width + bodySize;
    const x = portrait ? Math.round((widthDots - w) / 2) : textLeft;
    const h = Math.round(bodySize * 1.5);
    if (paint) {
      ctx.strokeStyle = red;
      ctx.lineWidth = Math.max(2, Math.round(mm(0.35)));
      ctx.strokeRect(x, cursorY, w, h);
      ctx.fillStyle = red;
      ctx.textAlign = 'center';
      ctx.fillText(label, x + w / 2, cursorY + Math.round(bodySize * 0.25));
      ctx.textAlign = portrait ? 'center' : 'left';
    }
    cursorY += h + Math.round(bodySize * 0.3);
  } else {
    ctx.fillStyle = black;
    ctx.font = `${bodySize}px ${FONT}`;
    if (paint) {
      ctx.fillText(`${visit.check_type} ${visit.check_number || ''}`.trim(), centreX, cursorY, textWidth);
    }
    cursorY += Math.round(bodySize * 1.3);
  }

  if (site.badge_note) {
    ctx.fillStyle = black;
    ctx.font = `${Math.round(bodySize * 0.85)}px ${FONT}`;
    for (const line of wrapText(ctx, site.badge_note, textWidth, 2)) {
      if (paint) ctx.fillText(line, centreX, cursorY, textWidth);
      cursorY += Math.round(bodySize * 1.1);
    }
  }

  return cursorY - (startY === null ? pad : startY);
}

/**
 * Produces the PNG that gets sent to the printer.
 *
 * The bitmap is always 696 dots across, because that is the printer's fixed head
 * width on a 62 mm roll. With rotation the badge is laid out along the length of
 * the label instead and the finished image is turned, so the content still lands
 * within those 696 dots.
 */
export async function renderBadgePng(visit, site) {
  const rotate = Number(site.printer_rotate) || 0;
  const lengthMm = Number(site.badge_height_mm) || 90;
  const turned = rotate === 90 || rotate === 270;

  const acrossDots = DOTS_ACROSS_62MM;
  const alongDots = mm(lengthMm);

  // Design canvas: swapped when the badge is laid out along the label.
  const designW = turned ? alongDots : acrossDots;
  const designH = turned ? acrossDots : alongDots;

  const design = createCanvas(designW, designH);
  const ctx = design.getContext('2d');
  // Only paint red when the loaded roll can actually print it.
  const accent = accentWillPrintRed(site);

  // Measure first, then draw the block centred down the label. Without this the
  // content hugs the top and leaves a wide blank strip at the bottom of every badge.
  const used = await drawBadge(ctx, designW, designH, visit, site, accent, null);
  const pad = Math.round(Math.min(designW, designH) * 0.07);
  const startY = Math.max(pad, Math.round((designH - used) / 2));
  await drawBadge(ctx, designW, designH, visit, site, accent, startY);

  if (!rotate) return design.toBuffer('image/png');

  const out = createCanvas(turned ? acrossDots : designW, turned ? alongDots : designH);
  const outCtx = out.getContext('2d');
  outCtx.fillStyle = '#ffffff';
  outCtx.fillRect(0, 0, out.width, out.height);
  outCtx.translate(out.width / 2, out.height / 2);
  outCtx.rotate((rotate * Math.PI) / 180);
  outCtx.drawImage(design, -designW / 2, -designH / 2);
  return out.toBuffer('image/png');
}

/* -------------------------------------------------------------- sending */

/**
 * brother_ql reports failures as a Python traceback. Nobody at a front desk can
 * act on that, so the useful last line is pulled out and the common network
 * failures are rewritten as something with a next step.
 */
function explainPrintError(output, host) {
  const lines = String(output || '')
    .split('\n')
    .map((l) => l.trim())
    .filter((l) => l && !/^deprecation warning/i.test(l));
  const last = lines[lines.length - 1] || '';

  if (/Connection refused/i.test(last)) {
    return `${host} refused the connection. Check the printer is switched on and that port 9100 is the right one.`;
  }
  if (/timed out|timeout/i.test(last)) {
    return `${host} did not answer. Check the IP address and that the printer is on the same network as the server.`;
  }
  if (/No route to host|Network is unreachable/i.test(last)) {
    return `${host} cannot be reached from the server. Check the address and any firewall between them.`;
  }
  if (/Name or service not known|getaddrinfo/i.test(last)) {
    return `${host} could not be resolved. Use the printer's IP address rather than a name.`;
  }
  if (/Unknown label|label/i.test(last) && /identifier/i.test(last)) {
    return 'The printer rejected the label size. Check the roll loaded matches the badge settings.';
  }
  if (/wrong roll|WrongMedia|media/i.test(last)) {
    return 'The printer says the roll is wrong. Check "Roll loaded in the printer" matches what is actually in the machine — a black and red job is refused on a plain roll.';
  }
  return last || 'The printer did not accept the job.';
}

function runBrotherQl(args, timeoutMs) {
  return new Promise((resolve, reject) => {
    execFile(
      config.printing.command,
      args,
      { timeout: timeoutMs, env: { ...process.env, BROTHER_QL_PRINTER: '', BROTHER_QL_MODEL: '' } },
      (err, stdout, stderr) => {
        const output = `${stdout || ''}${stderr || ''}`.trim();
        if (err) {
          if (err.code === 'ENOENT') {
            return reject(
              new Error(
                `${config.printing.command} is not installed in the container. Rebuild the image, or set PRINT_COMMAND.`
              )
            );
          }
          if (err.killed) return reject(new Error('The printer did not respond in time.'));
          return reject(new Error(output || err.message));
        }
        resolve(output);
      }
    );
  });
}

/**
 * Renders and prints one badge. Resolves with a short description on success and
 * rejects with something an admin can act on.
 */
export async function printBadge(visit, site) {
  if (!isConfigured(site)) throw new Error('Server printing is not turned on for this site.');

  const png = await renderBadgePng(visit, site);
  const file = path.join(os.tmpdir(), `badge-${crypto.randomBytes(6).toString('hex')}.png`);
  fs.writeFileSync(file, png);

  const port = Number(site.printer_port) || 9100;
  const target = `tcp://${site.printer_host}:${port}`;

  try {
    await runBrotherQl(
      [
        '--backend', 'network',
        '--model', site.printer_model || 'QL-820NWB',
        '--printer', target,
        'print',
        '--label', labelFor(site),
        file,
      ],
      config.printing.timeoutMs
    );
    note(site.id, true, `Printed to ${site.printer_host}`);
    return { ok: true, target };
  } catch (err) {
    const friendly = explainPrintError(err.message, site.printer_host);
    note(site.id, false, friendly);
    throw new Error(friendly);
  } finally {
    fs.rm(file, { force: true }, () => {});
  }
}

/** A sample badge, for checking the printer and the layout without a real visit. */
export function sampleVisit(site) {
  return {
    id: 0,
    first_name: 'Sample',
    last_name: 'Visitor',
    host_name: 'Jess Rogerson',
    check_type: 'NONE',
    check_number: null,
    photo_path: null,
    signed_in_at: new Date().toISOString(),
    site_name: site.name,
  };
}

export function available() {
  return new Promise((resolve) => {
    execFile(config.printing.command, ['--version'], (err) => resolve(!err));
  });
}