#!/usr/bin/env node
/**
 * lint-command-contract.cjs  (ADR-0002)
 *
 * Enforces the commands/gsd/*.md contract across all 65 command files:
 *
 *   1. name:        present, non-empty, matches gsd: or gsd- prefix
 *   2. description: present, non-empty
 *   3. allowed-tools: block present, non-empty, all entries from CANONICAL_TOOLS
 *   4. execution_context @-refs: every @-reference resolves to an existing file on disk
 *   5. execution_context @-refs: each appears on its own line (no trailing prose)
 *
 * Exit 0 = clean. Exit 1 = violations (with diagnostics).
 */

'use strict';

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

const ROOT          = path.join(__dirname, '..');
const COMMANDS_DIR  = path.join(ROOT, 'commands', 'gsd');
const GSD_ROOT      = path.join(ROOT, 'get-shit-done');

// All tool names the Claude Code / GSD runtime recognises.
// Wildcard entries (mcp__context7__*) match any mcp__context7__ prefixed name.
const CANONICAL_TOOLS = new Set([
  'Read', 'Write', 'Edit', 'Bash', 'Glob', 'Grep',
  'Task', 'Agent', 'Skill', 'SlashCommand',
  'AskUserQuestion', 'WebFetch', 'WebSearch', 'TodoWrite',
  'mcp__context7__resolve-library-id',
  'mcp__context7__query-docs',
  'mcp__context7__*',
]);

// ─── parsers ─────────────────────────────────────────────────────────────────

function parseFrontmatter(content) {
  const lines = content.split('\n');
  if (lines[0].trim() !== '---') return {};
  const end = lines.indexOf('---', 1);
  if (end === -1) return {};
  const fm = {};
  let key = null;
  for (const line of lines.slice(1, end)) {
    const kv = line.match(/^([a-zA-Z0-9_-]+):\s*(.*)/);
    if (kv) { key = kv[1]; fm[key] = kv[2].trim(); }
    else if (key && line.match(/^\s+-\s+/)) {
      const val = line.replace(/^\s+-\s+/, '').trim();
      fm[key] = fm[key] ? fm[key] + '\n' + val : val;
    }
  }
  return fm;
}

function extractExecutionContextRefs(content) {
  const results = [];
  const blockRe = /<execution_context(?:_extended)?>([\s\S]*?)<\/execution_context(?:_extended)?>/g;
  let m;
  while ((m = blockRe.exec(content)) !== null) {
    const block = m[1];
    for (const rawLine of block.split('\n')) {
      const line = rawLine.trim();
      if (!line.startsWith('@')) continue;
      // Capture the @-reference token (stops at first space)
      const refToken = line.split(/\s+/)[0];
      const hasTrailingProse = line.length > refToken.length;
      // Normalise path: strip @~/.../get-shit-done/ or @$HOME/.../get-shit-done/ prefix
      const normalized = refToken
        .replace(/^@(?:~|\$HOME)\//, '')
        .replace(/^(?:\.claude\/)?(?:get-shit-done\/)?/, '');
      results.push({ ref: refToken, normalized, hasTrailingProse, rawLine });
    }
  }
  return results;
}

// ─── check one file ───────────────────────────────────────────────────────────

function check(filePath) {
  const content  = fs.readFileSync(filePath, 'utf-8');
  const rel      = path.relative(ROOT, filePath);
  const fm       = parseFrontmatter(content);
  const violations = [];

  // 1. name: present + gsd: / gsd- prefix
  if (!fm.name || !fm.name.trim()) {
    violations.push('name: field missing or empty');
  } else if (!/^gsd[:-]/.test(fm.name.trim())) {
    violations.push(`name: must start with "gsd:" or "gsd-", got "${fm.name.trim()}"`);
  }

  // 2. description: present + non-empty
  if (!fm.description || !fm.description.trim()) {
    violations.push('description: field missing or empty');
  }

  // 3. allowed-tools: present + non-empty + all entries canonical
  if (!fm['allowed-tools'] || !fm['allowed-tools'].trim()) {
    violations.push('allowed-tools: block missing or empty');
  } else {
    const tools = fm['allowed-tools'].split('\n').map(t => t.trim()).filter(Boolean);
    for (const tool of tools) {
      const valid =
        CANONICAL_TOOLS.has(tool) ||
        (tool.startsWith('mcp__context7__') && CANONICAL_TOOLS.has('mcp__context7__*'));
      if (!valid) violations.push(`allowed-tools: unknown tool "${tool}"`);
    }
  }

  // 4+5. execution_context @-refs resolve + no trailing prose
  const refs = extractExecutionContextRefs(content);
  for (const { ref, normalized, hasTrailingProse } of refs) {
    const absPath = path.join(GSD_ROOT, normalized);
    if (!fs.existsSync(absPath)) {
      violations.push(`execution_context: @-ref "${normalized}" does not exist on disk`);
    }
    if (hasTrailingProse) {
      violations.push(`execution_context: @-ref "${ref}" has trailing prose on the same line`);
    }
  }

  if (violations.length === 0) return null;
  return { file: rel, violations };
}

// ─── run ─────────────────────────────────────────────────────────────────────

const commandFiles = fs
  .readdirSync(COMMANDS_DIR)
  .filter(f => f.endsWith('.md'))
  .map(f => path.join(COMMANDS_DIR, f));

const results = commandFiles.map(check).filter(Boolean);

if (results.length === 0) {
  console.log(
    `ok lint-command-contract: ${commandFiles.length} command files checked, 0 violations`,
  );
  process.exit(0);
}

const total = results.reduce((n, r) => n + r.violations.length, 0);
process.stderr.write(
  `\nERROR lint-command-contract: ${total} violation(s) across ${results.length} file(s)\n\n`,
);
for (const r of results) {
  process.stderr.write(`  ${r.file}\n`);
  for (const v of r.violations) {
    process.stderr.write(`    - ${v}\n`);
  }
  process.stderr.write('\n');
}
process.stderr.write('See docs/adr/0002-command-contract-validation-module.md for the contract spec.\n\n');
process.exit(1);