/**
 * Pure utility functions – text processing, date formatting, game detection,
 * priority helpers, template variables.
 */
const { CONFIG, GAME_NAMES, GAME_ALIASES, TICKET_TAGS } = require('./config');

// --- TEXT PROCESSING ---

const BLOCK_TAG_REGEX =
  /<\/(p|div|li|h[1-6]|tr|table|section|article|blockquote)>/gi;

function escapeRegex(str) {
  return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

function decodeHtmlEntities(str) {
  if (!str) return '';
  return str
    .replace(/&amp;/g, '&')
    .replace(/&lt;/g, '<')
    .replace(/&gt;/g, '>')
    .replace(/&quot;/g, '"')
    .replace(/&#39;/g, "'")
    .replace(/&nbsp;/g, ' ');
}

function htmlToTextWithBlocks(html) {
  return decodeHtmlEntities(
    html
      .replace(/\r\n/g, '\n')
      .replace(/<br\s*\/?>/gi, '\n')
      .replace(BLOCK_TAG_REGEX, '\n\n')
      .replace(/<(ul|ol)[^>]*>/gi, '\n')
      .replace(/<[^>]*>?/gm, '')
  );
}

// --- EMAIL BODY EXTRACTION ---

function decodeGmailData(p) {
  if (!p.body?.data) return '';
  let data = Buffer.from(p.body.data, 'base64').toString('utf8');

  const isQuotedPrintable = p.headers?.some(
    h =>
      h.name.toLowerCase() === 'content-transfer-encoding' &&
      h.value.toLowerCase() === 'quoted-printable'
  );
  if (isQuotedPrintable) {
    data = data
      .replace(/=\r?\n/g, '')
      .replace(/=([0-9A-F]{2})/gi, (m, hex) =>
        String.fromCharCode(parseInt(hex, 16))
      );
  }
  return data;
}

function getCleanBody(payload) {
  let body = '';

  const findParts = parts => {
    for (const part of parts) {
      if (part.mimeType === 'text/plain' && part.body?.data && !body) {
        body = decodeGmailData(part);
      }
      if (part.mimeType === 'text/html' && part.body?.data && !body) {
        body = decodeGmailData(part);
      }
      if (part.parts) findParts(part.parts);
    }
  };

  if (payload.parts) {
    findParts(payload.parts);
  } else if (payload.body?.data) {
    body = decodeGmailData(payload);
  }

  return body || payload.snippet || '';
}

// --- QUOTE / FOOTER STRIPPING ---

function stripEmailQuotes(text) {
  let cleaned = text.replace(/\r\n/g, '\n');

  const markers = [
    /\n_{5,}\s*$/m,
    /\nFrom:\s.*<.*@.*>/i,
    /\nSent:\s.*$/i,
    /\nTo:\s.*$/i,
    /\nSubject:\s.*$/i,
    /\nOn .* wrote:/i
  ];

  for (const m of markers) {
    const match = cleaned.match(m);
    if (match) {
      cleaned = cleaned.substring(0, match.index);
      break;
    }
  }

  return cleaned.trim();
}

function stripMobileFooter(text) {
  if (!text) return text;

  const patterns = [
    /Sent from my iPhone/i,
    /Sent from my iPad/i,
    /Sent from my Apple Watch/i,
    /Sent from my Mac/i,
    /Sent from my mobile device/i,
    /Sent from my phone/i,
    /Sent from my smartphone/i,
    /Sent from my Android(?: phone| device)?/i,
    /Sent from my Samsung Galaxy smartphone/i,
    /Sent from Samsung Mobile/i,
    /Sent from my Galaxy/i,
    /Sent from my BlackBerry/i,
    /Sent from my Windows Phone/i,
    /Sent from Outlook for iOS/i,
    /Sent from Outlook for Android/i,
    /Sent from Yahoo Mail for iPhone(?: \/ Android)?/i,
    /Sent from Yahoo Mail for Android/i,
    /Sent from my Amazon Fire/i,
    /Get\s+Outlook\s+for\s+iOS/i,
    /Get\s+Outlook\s+for\s+Android/i,
    /Sent with Proton Mail secure email\./i
  ];

  let result = text;

  for (const re of patterns) {
    const rx = new RegExp(`\\n*${re.source}\\s*`, 'i');
    result = result.replace(rx, '');
  }

  return result;
}

// --- EMAIL HELPERS ---

function extractRawEmail(headerValue) {
  const match = headerValue.match(/<([^>]+)>/);
  return match ? match[1].trim() : headerValue.trim();
}

// --- DATE ---

const getFormattedDate = () => {
  const now = new Date();
  const datePart = now
    .toLocaleDateString('en-US', {
      month: '2-digit',
      day: '2-digit',
      year: 'numeric'
    })
    .replace(/\//g, '-');
  const timePart = now.toLocaleTimeString('en-US', {
    hour: '2-digit',
    minute: '2-digit',
    second: '2-digit',
    hour12: true
  });
  const tzPart = new Intl.DateTimeFormat('en-US', {
    timeZoneName: 'short'
  })
    .formatToParts(now)
    .find(p => p.type === 'timeZoneName').value;
  return `${datePart} ${timePart} ${tzPart}`;
};

// --- GAME DETECTION ---

const detectGame = (subject, body) => {
  const txt = `${subject} ${body}`.toLowerCase();

  for (const game of GAME_NAMES) {
    const g = game.toLowerCase();
    const re = new RegExp(`\\b${escapeRegex(g)}\\b`, 'i');
    if (re.test(txt)) return game;
  }

  for (const [alias, fullName] of Object.entries(GAME_ALIASES)) {
    const a = alias.toLowerCase();
    const re = new RegExp(`\\b${escapeRegex(a)}\\b`, 'i');
    if (re.test(txt)) return fullName;
  }

  return 'Not Mentioned';
};

// --- PRIORITY ---

function getPriorityEmoji(priority) {
  switch (priority) {
    case 'high': return CONFIG.PRIORITY_HIGH_EMOJI;
    case 'low': return CONFIG.PRIORITY_LOW_EMOJI;
    case 'normal':
    case 'medium':
    default: return CONFIG.PRIORITY_MEDIUM_EMOJI;
  }
}

function getPriorityColor(priority) {
  switch (priority) {
    case 'high': return 0xFF0000;
    case 'low': return 0x00FF00;
    case 'normal':
    case 'medium':
    default: return CONFIG.EMBED_COLOR_INFO;
  }
}

/** Returns emoji for a ticket-tag key (e.g. server-down → ⬇️). Priority always comes first in channel name, then tag. */
function getTicketTagEmoji(tagKey) {
  if (!tagKey) return '';
  const t = (TICKET_TAGS || []).find(x => x.value === tagKey);
  return t ? t.emoji : '';
}

// --- TEMPLATE VARIABLES ---

function replaceVariables(template, context = {}) {
  if (!template) return '';

  let result = template;

  if (context.ticket) {
    result = result.replace(/{ticket\.user}/g, context.ticket.sender_name || 'Unknown');
    result = result.replace(/{ticket\.creator}/g, context.ticket.sender_name || 'Unknown');
    result = result.replace(/{ticket\.email}/g, context.ticket.senderEmail || '');
    result = result.replace(/{ticket\.number}/g, context.ticket.ticketNumber != null ? context.ticket.ticketNumber : 'N/A');
    result = result.replace(/{ticket\.subject}/g, context.ticket.subject || 'No subject');
    result = result.replace(/{ticket\.claimed}/g, context.ticket.claimedBy ? 'Yes' : 'No');
    result = result.replace(/{ticket\.claimedby}/g, context.ticket.claimedBy || 'Unclaimed');
    result = result.replace(/{ticket\.priority}/g, context.ticket.priority || 'normal');
    result = result.replace(/{ticket\.id}/g, context.ticket.gmailThreadId || '');
  }

  if (context.staff) {
    result = result.replace(/{staff\.user}/g, context.staff.username || '');
    result = result.replace(/{staff\.name}/g, context.staff.displayName || context.staff.username || '');
    result = result.replace(/{staff\.mention}/g, context.staff.mention || '');
  }

  if (context.guild) {
    result = result.replace(/{server\.name}/g, context.guild.name || '');
    result = result.replace(/{server\.membercount}/g, context.guild.memberCount?.toString() || '0');
  }

  if (context.hours !== undefined) {
    result = result.replace(/{hours}/g, context.hours.toString());
  }

  const now = new Date();
  result = result.replace(/{date}/g, now.toLocaleDateString());
  result = result.replace(/{time}/g, now.toLocaleTimeString());

  return result;
}

module.exports = {
  BLOCK_TAG_REGEX,
  escapeRegex,
  decodeHtmlEntities,
  htmlToTextWithBlocks,
  decodeGmailData,
  getCleanBody,
  stripEmailQuotes,
  stripMobileFooter,
  extractRawEmail,
  getFormattedDate,
  detectGame,
  getPriorityEmoji,
  getPriorityColor,
  getTicketTagEmoji,
  replaceVariables
};