#!/usr/bin/env node
/**
 * validate-artifact-paths.js
 *
 * Guards the spec -> plan -> build pipeline against silent artifact-path drift.
 *
 * The `/spec` and `/plan` commands (producers) write their artifacts to a set
 * of paths that the `/build` command and the spec/plan skills (consumers) read
 * back. When a producer moves an artifact without updating the consumers — as
 * in PR #93, which pointed `/spec` and `/plan` at docs/features/[name]/ while
 * `/build` still required SPEC.md and tasks/plan.md — the pipeline breaks, and
 * nothing else in CI catches it (command parity only compares descriptions).
 *
 * This validator enforces one canonical set of spec/plan/todo artifact paths
 * across every file in the pipeline. Changing the convention means updating
 * ARTIFACT_ALLOWLIST *and* every guarded file in the same change; CI fails
 * until they agree.
 *
 * Scope is deliberately narrow: only spec/plan/todo artifacts, only the files
 * that define the pipeline. It is not a general markdown path linter.
 *
 * Exit codes: 0 = all clear, 1 = one or more drifted paths.
 */

'use strict';

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

const ROOT = path.resolve(__dirname, '..');

// The canonical spec/plan/todo artifact paths. These are the only artifact
// file paths the pipeline files may reference. To change the convention, edit
// this list and update every guarded file to match — CI enforces the pairing.
const ARTIFACT_ALLOWLIST = new Set([
  'SPEC.md',        // spec, project root (produced by /spec, read by /build)
  'docs/SPEC.md',   // spec, alternate location accepted by /build
  'tasks/plan.md',  // plan (produced by /plan, read by /build)
  'tasks/todo.md',  // task list (produced by /plan)
]);

// The files that make up the spec -> plan -> build pipeline. Absent files are
// skipped, not failed: this validator checks path consistency, not presence.
const GUARDED_FILES = [
  '.claude/commands/spec.md',
  '.claude/commands/plan.md',
  '.claude/commands/build.md',
  'skills/spec-driven-development/SKILL.md',
  'skills/planning-and-task-breakdown/SKILL.md',
  'docs/getting-started.md',
  'docs/adoption-guide.md',
];

// Matches a path-like token ending in a spec/plan/todo artifact filename,
// including an optional directory prefix with bracket placeholders like
// docs/features/[feature-name]/spec.md. Case-insensitive so SPEC.md and a
// drifted spec.md are both caught, then compared against the allowlist.
const ARTIFACT_RE = /(?:[A-Za-z0-9._[\]-]+\/)*(?:spec|plan|todo)\.md/gi;

function findViolations(relPath) {
  const abs = path.join(ROOT, relPath);
  if (!fs.existsSync(abs)) return null; // skipped

  const violations = [];
  const lines = fs.readFileSync(abs, 'utf8').split(/\r?\n/);
  lines.forEach((line, i) => {
    const matches = line.match(ARTIFACT_RE);
    if (!matches) return;
    for (const match of matches) {
      if (!ARTIFACT_ALLOWLIST.has(match)) {
        violations.push({ line: i + 1, match });
      }
    }
  });
  return violations;
}

function main() {
  console.log('Checking spec/plan/todo artifact paths...\n');

  let checked = 0;
  let errors = 0;

  for (const relPath of GUARDED_FILES) {
    const violations = findViolations(relPath);
    if (violations === null) continue; // file not present, skip
    checked++;

    if (violations.length === 0) {
      console.log(`  ✓  ${relPath}`);
    } else {
      console.log(`  ✗  ${relPath}`);
      for (const { line, match } of violations) {
        console.log(`       L${line}: ${match} — not an approved spec/plan/todo artifact path`);
        errors++;
      }
    }
  }

  const status = errors > 0 ? 'FAILED' : 'PASSED';
  console.log(`\n${checked} files checked — ${errors} error(s) — ${status}`);

  if (errors > 0) {
    console.log('\nThe spec -> plan -> build pipeline expects one set of artifact paths.');
    console.log('Either use a path from ARTIFACT_ALLOWLIST, or change the convention');
    console.log('across every guarded file and update the allowlist in the same change.');
    process.exit(1);
  }
}

main();