#!/usr/bin/env node
// gsd-hook-version: {{GSD_VERSION}}
// Claude Code Statusline - GSD Edition
// Shows: model | current task (or GSD state) | directory | context usage

const fs = require('fs');
const path = require('path');
const os = require('os');

// --- GSD state reader -------------------------------------------------------

/**
 * Walk up from dir looking for .planning/STATE.md.
 * Returns parsed state object or null.
 */
function readGsdState(dir) {
  const home = os.homedir();
  let current = dir;
  for (let i = 0; i < 10; i++) {
    const candidate = path.join(current, '.planning', 'STATE.md');
    if (fs.existsSync(candidate)) {
      try {
        return parseStateMd(fs.readFileSync(candidate, 'utf8'));
      } catch (e) {
        return null;
      }
    }
    const parent = path.dirname(current);
    if (parent === current || current === home) break;
    current = parent;
  }
  return null;
}

/**
 * Parse STATE.md frontmatter + Phase line from body.
 * Returns { status, milestone, milestoneName, phaseNum, phaseTotal, phaseName }
 */
function parseStateMd(content) {
  const state = {};

  // YAML frontmatter between --- markers
  const fmMatch = content.match(/^---\n([\s\S]*?)\n---/);
  if (fmMatch) {
    for (const line of fmMatch[1].split('\n')) {
      const m = line.match(/^(\w+):\s*(.+)/);
      if (!m) continue;
      const [, key, val] = m;
      const v = val.trim().replace(/^["']|["']$/g, '');
      if (key === 'status') state.status = v === 'null' ? null : v;
      if (key === 'milestone') state.milestone = v === 'null' ? null : v;
      if (key === 'milestone_name') state.milestoneName = v === 'null' ? null : v;
    }
  }

  // Phase: N of M (name)  or  Phase: none active (...)
  const phaseMatch = content.match(/^Phase:\s*(\d+)\s+of\s+(\d+)(?:\s+\(([^)]+)\))?/m);
  if (phaseMatch) {
    state.phaseNum = phaseMatch[1];
    state.phaseTotal = phaseMatch[2];
    state.phaseName = phaseMatch[3] || null;
  }

  // Fallback: parse Status: from body when frontmatter is absent
  if (!state.status) {
    const bodyStatus = content.match(/^Status:\s*(.+)/m);
    if (bodyStatus) {
      const raw = bodyStatus[1].trim().toLowerCase();
      if (raw.includes('ready to plan') || raw.includes('planning')) state.status = 'planning';
      else if (raw.includes('execut')) state.status = 'executing';
      else if (raw.includes('complet') || raw.includes('archived')) state.status = 'complete';
    }
  }

  return state;
}

/**
 * Format GSD state into display string.
 * Format: "v1.9 Code Quality · executing · fix-graphiti-deployment (1/5)"
 * Gracefully degrades when parts are missing.
 */
function formatGsdState(s) {
  const parts = [];

  // Milestone: version + name (skip placeholder "milestone")
  if (s.milestone || s.milestoneName) {
    const ver = s.milestone || '';
    const name = (s.milestoneName && s.milestoneName !== 'milestone') ? s.milestoneName : '';
    const ms = [ver, name].filter(Boolean).join(' ');
    if (ms) parts.push(ms);
  }

  // Status
  if (s.status) parts.push(s.status);

  // Phase
  if (s.phaseNum && s.phaseTotal) {
    const phase = s.phaseName
      ? `${s.phaseName} (${s.phaseNum}/${s.phaseTotal})`
      : `ph ${s.phaseNum}/${s.phaseTotal}`;
    parts.push(phase);
  }

  return parts.join(' · ');
}

// --- stdin ------------------------------------------------------------------

function runStatusline() {
  let input = '';
  // Timeout guard: if stdin doesn't close within 3s (e.g. pipe issues on
  // Windows/Git Bash), exit silently instead of hanging. See #775.
  const stdinTimeout = setTimeout(() => process.exit(0), 3000);
  process.stdin.setEncoding('utf8');
  process.stdin.on('data', chunk => input += chunk);
  process.stdin.on('end', () => {
  clearTimeout(stdinTimeout);
  try {
    const data = JSON.parse(input);
    const model = data.model?.display_name || 'Claude';
    const dir = data.workspace?.current_dir || process.cwd();
    const session = data.session_id || '';
    const remaining = data.context_window?.remaining_percentage;

    // Context window display (shows USED percentage scaled to usable context)
    // Claude Code reserves a buffer for autocompact. By default this is ~16.5%
    // of the total window, but users can override it via CLAUDE_CODE_AUTO_COMPACT_WINDOW
    // (a token count). When the env var is set, compute the buffer % dynamically so
    // the meter correctly reflects early-compaction configurations (#2219).
    const totalCtx = data.context_window?.total_tokens || 1_000_000;
    const acw = parseInt(process.env.CLAUDE_CODE_AUTO_COMPACT_WINDOW || '0', 10);
    const AUTO_COMPACT_BUFFER_PCT = acw > 0
      ? Math.min(100, (acw / totalCtx) * 100)
      : 16.5;
    let ctx = '';
    if (remaining != null) {
      // Normalize: subtract buffer from remaining, scale to usable range
      const usableRemaining = Math.max(0, ((remaining - AUTO_COMPACT_BUFFER_PCT) / (100 - AUTO_COMPACT_BUFFER_PCT)) * 100);
      const used = Math.max(0, Math.min(100, Math.round(100 - usableRemaining)));

      // Write context metrics to bridge file for the context-monitor PostToolUse hook.
      // The monitor reads this file to inject agent-facing warnings when context is low.
      // Reject session IDs with path separators or traversal sequences to prevent
      // a malicious session_id from writing files outside the temp directory.
      const sessionSafe = session && !/[/\\]|\.\./.test(session);
      if (sessionSafe) {
        try {
          const bridgePath = path.join(os.tmpdir(), `claude-ctx-${session}.json`);
          const bridgeData = JSON.stringify({
            session_id: session,
            remaining_percentage: remaining,
            used_pct: used,
            timestamp: Math.floor(Date.now() / 1000)
          });
          fs.writeFileSync(bridgePath, bridgeData);
        } catch (e) {
          // Silent fail -- bridge is best-effort, don't break statusline
        }
      }

      // Build progress bar (10 segments)
      const filled = Math.floor(used / 10);
      const bar = '█'.repeat(filled) + '░'.repeat(10 - filled);

      // Color based on usable context thresholds
      if (used < 50) {
        ctx = ` \x1b[32m${bar} ${used}%\x1b[0m`;
      } else if (used < 65) {
        ctx = ` \x1b[33m${bar} ${used}%\x1b[0m`;
      } else if (used < 80) {
        ctx = ` \x1b[38;5;208m${bar} ${used}%\x1b[0m`;
      } else {
        ctx = ` \x1b[5;31m💀 ${bar} ${used}%\x1b[0m`;
      }
    }

    // Current task from todos
    let task = '';
    const homeDir = os.homedir();
    // Respect CLAUDE_CONFIG_DIR for custom config directory setups (#870)
    const claudeDir = process.env.CLAUDE_CONFIG_DIR || path.join(homeDir, '.claude');
    const todosDir = path.join(claudeDir, 'todos');
    if (session && fs.existsSync(todosDir)) {
      try {
        const files = fs.readdirSync(todosDir)
          .filter(f => f.startsWith(session) && f.includes('-agent-') && f.endsWith('.json'))
          .map(f => ({ name: f, mtime: fs.statSync(path.join(todosDir, f)).mtime }))
          .sort((a, b) => b.mtime - a.mtime);

        if (files.length > 0) {
          try {
            const todos = JSON.parse(fs.readFileSync(path.join(todosDir, files[0].name), 'utf8'));
            const inProgress = todos.find(t => t.status === 'in_progress');
            if (inProgress) task = inProgress.activeForm || '';
          } catch (e) {}
        }
      } catch (e) {
        // Silently fail on file system errors - don't break statusline
      }
    }

    // GSD state (milestone · status · phase) — shown when no todo task
    const gsdStateStr = task ? '' : formatGsdState(readGsdState(dir) || {});

    // GSD update available?
    // Check shared cache first (#1421), fall back to runtime-specific cache for
    // backward compatibility with older gsd-check-update.js versions.
    let gsdUpdate = '';
    const sharedCacheFile = path.join(homeDir, '.cache', 'gsd', 'gsd-update-check.json');
    const legacyCacheFile = path.join(claudeDir, 'cache', 'gsd-update-check.json');
    const cacheFile = fs.existsSync(sharedCacheFile) ? sharedCacheFile : legacyCacheFile;
    if (fs.existsSync(cacheFile)) {
      try {
        const cache = JSON.parse(fs.readFileSync(cacheFile, 'utf8'));
        if (cache.update_available) {
          gsdUpdate = '\x1b[33m⬆ /gsd-update\x1b[0m │ ';
        }
        if (cache.stale_hooks && cache.stale_hooks.length > 0) {
          // If installed version is ahead of npm latest, this is a dev install.
          // Running /gsd-update would downgrade — show a contextual warning instead.
          const isDevInstall = (() => {
            if (!cache.installed || !cache.latest || cache.latest === 'unknown') return false;
            const parseV = v => v.replace(/^v/, '').split('.').map(Number);
            const [ai, bi, ci] = parseV(cache.installed);
            const [an, bn, cn] = parseV(cache.latest);
            return ai > an || (ai === an && bi > bn) || (ai === an && bi === bn && ci > cn);
          })();
          if (isDevInstall) {
            gsdUpdate += '\x1b[33m⚠ dev install — re-run installer to sync hooks\x1b[0m │ ';
          } else {
            gsdUpdate += '\x1b[31m⚠ stale hooks — run /gsd-update\x1b[0m │ ';
          }
        }
      } catch (e) {}
    }

    // Output
    const dirname = path.basename(dir);
    const middle = task
      ? `\x1b[1m${task}\x1b[0m`
      : gsdStateStr
        ? `\x1b[2m${gsdStateStr}\x1b[0m`
        : null;

    if (middle) {
      process.stdout.write(`${gsdUpdate}\x1b[2m${model}\x1b[0m │ ${middle} │ \x1b[2m${dirname}\x1b[0m${ctx}`);
    } else {
      process.stdout.write(`${gsdUpdate}\x1b[2m${model}\x1b[0m │ \x1b[2m${dirname}\x1b[0m${ctx}`);
    }
  } catch (e) {
    // Silent fail - don't break statusline on parse errors
  }
});
}

// Export helpers for unit tests. Harmless when run as a script.
module.exports = { readGsdState, parseStateMd, formatGsdState };

if (require.main === module) runStatusline();