#!/usr/bin/env node

// coaching-hook.mjs
// Event: SessionStart
// Purpose: Proactive coaching based on cycle position and OKR status.
// Zero npm dependencies. Target execution: <200ms.

import { readFileSync, existsSync, readdirSync } from 'node:fs';
import { join } from 'node:path';
import { parseFrontmatter } from '../../lib/frontmatter.mjs';

const cwd = process.cwd();
const configPath = join(cwd, '.claude', 'okr.local.md');

if (!existsSync(configPath)) {
  process.exit(0);
}

try {
  const content = readFileSync(configPath, 'utf8');
  const { raw, get } = parseFrontmatter(content);
  if (raw === null) process.exit(0);

  const cycleId = get('id');
  const fase = get('fase');
  if (!cycleId) process.exit(0);

  // Parse cycle type and dates
  const cycleMatch = cycleId.match(/^([TQ])(\d)-(\d{4})$/);
  if (!cycleMatch) process.exit(0);

  const [, type, num, year] = cycleMatch;
  const cycleNum = parseInt(num, 10);
  const cycleYear = parseInt(year, 10);

  // Calculate cycle start/end month (0-indexed)
  let startMonth, endMonth, totalWeeks;
  if (type === 'T') {
    startMonth = (cycleNum - 1) * 4; // T1=0(Jan), T2=4(May), T3=8(Sep)
    endMonth = startMonth + 3;        // T1=3(Apr), T2=7(Aug), T3=11(Dec)
    totalWeeks = 16;
  } else {
    startMonth = (cycleNum - 1) * 3;
    endMonth = startMonth + 2;
    totalWeeks = 13;
  }

  // Testable clock seam: OKR_NOW (ISO date) overrides the wall clock so the
  // phase branches (early/mid/late) can be asserted deterministically.
  const now = process.env.OKR_NOW ? new Date(process.env.OKR_NOW) : new Date();
  const cycleStart = new Date(cycleYear, startMonth, 1);
  const cycleEnd = new Date(cycleYear, endMonth + 1, 0); // last day of end month

  // Calculate current week in cycle
  const msPerWeek = 7 * 24 * 60 * 60 * 1000;
  const elapsed = now - cycleStart;
  const currentWeek = Math.max(1, Math.min(totalWeeks, Math.ceil(elapsed / msPerWeek)));

  // Determine phase
  let phase;
  if (now < cycleStart || now > cycleEnd) {
    phase = 'between';
  } else if (currentWeek <= 4) {
    phase = 'early';
  } else if (currentWeek <= totalWeeks - 4) {
    phase = 'mid';
  } else {
    phase = 'late';
  }

  // Check for at-risk KR in status
  let atRiskCount = 0;
  const okrDir = join(cwd, '.claude', 'okr');
  const statusPath = join(okrDir, 'syklus', cycleId, 'status.md');
  if (existsSync(statusPath)) {
    try {
      const statusContent = readFileSync(statusPath, 'utf8');
      const riskMatches = statusContent.match(/[Ii] fare|[Bb]lokkert|risk/gi);
      if (riskMatches) atRiskCount = riskMatches.length;
    } catch { /* skip */ }
  }

  // Check last archived cycle for learnings
  let lastLearning = '';
  const histDir = join(okrDir, 'historikk');
  if (existsSync(histDir)) {
    try {
      const dirs = readdirSync(histDir, { withFileTypes: true })
        .filter(d => d.isDirectory())
        .map(d => d.name)
        .sort()
        .reverse();
      if (dirs.length > 0) {
        const retroPath = join(histDir, dirs[0], 'retrospektiv.md');
        if (existsSync(retroPath)) {
          const retro = readFileSync(retroPath, 'utf8');
          const learningMatch = retro.match(/## (?:Laering|Læring) til neste syklus\n\n([\s\S]*?)(?:\n##|$)/);
          if (learningMatch) {
            const lines = learningMatch[1].trim().split('\n').filter(l => l.trim());
            if (lines.length > 0) lastLearning = lines[0].replace(/^[-*]\s*/, '');
          }
        }
      }
    } catch { /* skip */ }
  }

  // Build coaching message
  const parts = [];
  parts.push(`OKR coaching: Uke ${currentWeek} av ${totalWeeks} i ${cycleId}.`);

  if (phase === 'early') {
    parts.push('Tidlig i syklusen — fokus på alignment og kvalitetssikring av OKR.');
    parts.push('Anbefalt: /okr:gap (dekning mot tildelingsbrev), /okr:kvalitet (kvalitetssjekk).');
  } else if (phase === 'mid') {
    parts.push('Midtveis i syklusen — tid for fremdriftssjekk.');
    parts.push('Anbefalt: /okr:sporing (statusoppdatering og scoring).');
    if (atRiskCount > 0) {
      parts.push(`OBS: ${atRiskCount} KR er merket som i fare/blokkert i siste status.`);
    }
  } else if (phase === 'late') {
    parts.push('Syklusen nærmer seg slutt — fokus på sluttspurt og forberedelse.');
    parts.push('Anbefalt: /okr:sporing (endelig scoring), /okr:møter (review-møte).');
    if (currentWeek >= totalWeeks - 2) {
      parts.push('Mindre enn 2 uker igjen. Vurder /okr:oppsett arkiver for retrospektiv.');
    }
    if (atRiskCount > 0) {
      parts.push(`OBS: ${atRiskCount} KR er i fare — vurder tiltak eller juster forventninger.`);
    }
  } else {
    // between cycles
    parts.push('Mellom sykluser. Anbefalt: /okr:oppsett arkiver eller /okr:skriv for ny syklus.');
  }

  if (lastLearning) {
    parts.push(`Læring fra forrige syklus: "${lastLearning}"`);
  }

  const msg = parts.join(' ');
  process.stdout.write(JSON.stringify({ systemMessage: msg }));
} catch {
  // Graceful exit on any error — never block the user
  process.exit(0);
}