export function extractDomain(fromAddr) {
  const m = String(fromAddr || '').match(/@([A-Za-z0-9.-]+)/);
  return m ? m[1].toLowerCase() : '';
}

export function extractFirstJobNumber(text) {
  const t = String(text || '');
  // heuristic: prefer 8+ digit job numbers (e.g., 0222600001)
  const m = t.match(/\b\d{8,}\b/);
  return m ? m[0] : '';
}

export function validatePassword(pw) {
  const p = String(pw || '');
  if (p.length < 12) return 'Password must be at least 12 characters.';
  if (!/[A-Z]/.test(p)) return 'Password must include an uppercase letter.';
  if (!/[a-z]/.test(p)) return 'Password must include a lowercase letter.';
  if (!/\d/.test(p)) return 'Password must include a number.';
  return null;
}

export async function applyRulesToEmail(emailRow, rules) {
  const from = (emailRow.from_addr || '').toLowerCase();
  const subj = (emailRow.subject || '').toLowerCase();
  const body = (emailRow.body_text || '').toLowerCase();
  const thread = (emailRow.thread_key || '').toLowerCase();

  for (const r of rules) {
    if (!r.enabled) continue;
    const v = (r.match_value || '').toLowerCase();
    let hit = false;
    if (r.match_type === 'from_domain') {
      hit = v && from.includes('@') && from.split('@').pop()?.includes(v.replace(/^@/, ''));
    } else if (r.match_type === 'from_contains') {
      hit = v && from.includes(v);
    } else if (r.match_type === 'subject_contains') {
      hit = v && subj.includes(v);
    } else if (r.match_type === 'body_contains') {
      hit = v && body.includes(v);
    } else if (r.match_type === 'thread_key') {
      hit = v && thread && thread === v;
    }

    if (hit) {
      return { projectId: r.project_id, confidence: 0.9, ruleId: r.id };
    }
  }

  return null;
}

export function buildPCOBody(email, project) {
  return [
    `# Potential Change Order (PCO) — Draft`,
    ``,
    `**Project:** ${project?.name || ''}`,
    `**Job #:** ${project?.job_number || ''}`,
    `**Source email:** ${email?.subject || ''} (${email?.id || ''})`,
    `**From:** ${email?.from_addr || ''}`,
    `**Date:** ${email?.date || ''}`,
    ``,
    `## Description / Change event`,
    `- (Describe what changed and why)`,
    ``,
    `## Contract / drawing references`,
    `- (Sheet/spec refs)`,
    ``,
    `## Cost / schedule impact`,
    `- Labor:`,
    `- Material:`,
    `- Equipment:`,
    `- Schedule impact:`,
    ``,
    `## Supporting info`,
    `- Email excerpt:`,
    ``,
    `> ${String(email?.body_text || '').slice(0, 1200).replace(/\n/g, '\n> ')}`
  ].join('\n');
}

export function buildRFIBody(email, project) {
  return [
    `# RFI — Draft`,
    ``,
    `**Project:** ${project?.name || ''}`,
    `**Job #:** ${project?.job_number || ''}`,
    `**Source email:** ${email?.subject || ''} (${email?.id || ''})`,
    `**From:** ${email?.from_addr || ''}`,
    `**Date:** ${email?.date || ''}`,
    ``,
    `## Question`,
    `- (Write the question clearly)`,
    ``,
    `## Background`,
    `- (Why this is needed / conflict)`,
    ``,
    `## Drawing/spec references`,
    `- (Sheet/detail/spec section)`,
    ``,
    `## Proposed resolution (optional)`,
    `-`,
    ``,
    `## Supporting excerpt`,
    `> ${String(email?.body_text || '').slice(0, 1200).replace(/\n/g, '\n> ')}`
  ].join('\n');
}