#!/usr/bin/env node
/**
 * verify-docs-flow.mjs — documentation reading-flow and consistency verifier (M2, S-206)
 *
 * Asserts:
 *  (i)   every docs/*.md file is linked from docs/README.md
 *  (ii)  the reviewer CLI matrix is consistent across the four canonical sources
 *  (iii) the Telegram agent list matches the set of agents with helpers on disk
 *  (iv)  all repository-relative paths referenced in README.md and docs/ exist
 *
 * Exits 0 when all checks pass; exits 1 with a report when any check fails.
 *
 * Usage:
 *   node scripts/verify-docs-flow.mjs
 *   pnpm run verify:docs   (wired via package.json)
 */

import fs from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";

const __dirname = path.dirname(fileURLToPath(import.meta.url));
export const REPO_ROOT = path.resolve(__dirname, "..");

// ── (i) docs/README.md coverage ───────────────────────────────────────────

/**
 * Check that every *.md file under docs/ is linked from docs/README.md.
 * Returns an array of error strings (empty = pass).
 *
 * @param {string} repoRoot
 * @returns {Promise<string[]>}
 */
export async function checkDocsIndexCoverage(repoRoot) {
  const docsDir = path.join(repoRoot, "docs");
  const readmePath = path.join(docsDir, "README.md");

  if (!fs.existsSync(readmePath)) {
    return ["docs/README.md is missing"];
  }

  const readmeContent = fs.readFileSync(readmePath, "utf8");
  const errors = [];

  // Collect all *.md files under docs/ except README.md itself
  const mdFiles = fs
    .readdirSync(docsDir)
    .filter((f) => f.endsWith(".md") && f !== "README.md");

  for (const file of mdFiles) {
    // Accept both ./FILE.md and FILE.md link forms
    const linked =
      readmeContent.includes(`](${file})`) ||
      readmeContent.includes(`](./${file})`);
    if (!linked) {
      errors.push(`docs/README.md does not link to docs/${file}`);
    }
  }

  return errors;
}

// ── (ii) Reviewer matrix consistency ──────────────────────────────────────

/**
 * Canonical reviewer CLI names expected in workflow docs.
 * Order matters for the consistency check.
 */
const EXPECTED_REVIEWER_CLIS = ["codex", "claude", "cursor", "opencode", "pi"];

/**
 * Check that the reviewer CLI matrix is consistent across the four canonical
 * workflow docs. Returns an array of error strings (empty = pass).
 *
 * @param {string} repoRoot
 * @returns {Promise<string[]>}
 */
export async function checkReviewerMatrixConsistency(repoRoot) {
  const canonical = [
    "docs/CREATE-PLAN.md",
    "docs/IMPLEMENT-PLAN.md",
    "docs/DO-TASK.md",
    "docs/REVIEWERS.md",
  ];

  const errors = [];

  for (const docPath of canonical) {
    const fullPath = path.join(repoRoot, docPath);
    if (!fs.existsSync(fullPath)) {
      errors.push(`${docPath} is missing`);
      continue;
    }
    const content = fs.readFileSync(fullPath, "utf8");
    // Each canonical doc must reference all five CLIs
    for (const cli of EXPECTED_REVIEWER_CLIS) {
      if (!content.includes(`\`${cli}\``)) {
        errors.push(`${docPath}: does not mention reviewer CLI \`${cli}\``);
      }
    }
  }

  return errors;
}

// ── (iii) Telegram agent coverage ─────────────────────────────────────────

/**
 * Agents that must have helpers on disk in skills/reviewer-runtime/.
 * Non-Pi agents use the top-level directory; Pi uses the pi/ sub-directory.
 */
const TELEGRAM_AGENTS = [
  {
    id: "codex",
    helperPath: "skills/reviewer-runtime/notify-telegram.sh",
    telegramSectionKeyword: "Codex",
  },
  {
    id: "claude-code",
    helperPath: "skills/reviewer-runtime/notify-telegram.sh",
    telegramSectionKeyword: "Claude Code",
  },
  {
    id: "opencode",
    helperPath: "skills/reviewer-runtime/notify-telegram.sh",
    telegramSectionKeyword: "OpenCode",
  },
  {
    id: "cursor",
    helperPath: "skills/reviewer-runtime/notify-telegram.sh",
    telegramSectionKeyword: "Cursor",
  },
  {
    id: "pi",
    helperPath: "skills/reviewer-runtime/pi/notify-telegram.sh",
    telegramSectionKeyword: "Pi",
  },
];

/**
 * Check that docs/TELEGRAM-NOTIFICATIONS.md documents every agent that has a
 * notify-telegram.sh helper on disk. Returns an array of error strings.
 *
 * @param {string} repoRoot
 * @returns {Promise<string[]>}
 */
export async function checkTelegramAgentCoverage(repoRoot) {
  const telegramDoc = path.join(repoRoot, "docs", "TELEGRAM-NOTIFICATIONS.md");
  const errors = [];

  if (!fs.existsSync(telegramDoc)) {
    return ["docs/TELEGRAM-NOTIFICATIONS.md is missing"];
  }

  const content = fs.readFileSync(telegramDoc, "utf8");

  for (const agent of TELEGRAM_AGENTS) {
    const helperFullPath = path.join(repoRoot, agent.helperPath);
    if (!fs.existsSync(helperFullPath)) {
      errors.push(
        `Telegram agent ${agent.id}: helper ${agent.helperPath} does not exist on disk`
      );
      continue;
    }
    // The Telegram doc must mention this agent somewhere
    if (!content.includes(agent.telegramSectionKeyword)) {
      errors.push(
        `docs/TELEGRAM-NOTIFICATIONS.md does not document agent: ${agent.telegramSectionKeyword}`
      );
    }
  }

  // Pi-specific: must link to PI-COMMON-REVIEWER.md
  if (!content.includes("PI-COMMON-REVIEWER.md")) {
    errors.push(
      "docs/TELEGRAM-NOTIFICATIONS.md must link to docs/PI-COMMON-REVIEWER.md"
    );
  }

  return errors;
}

// ── (iv) Repo-relative path references ────────────────────────────────────

/**
 * Patterns to skip when checking path references — these are URLs and
 * non-filesystem references that look like repo paths but aren't.
 */
const PATH_SKIP_PATTERNS = [
  /^https?:\/\//,             // HTTP URLs
  /^\/tmp\//,                 // /tmp paths (runtime artifacts)
  /^\$\{/,                    // shell variable expansions
  /^~\//,                     // home directory paths
  /^\.\.?\//,                 // relative ./ or ../ — checked differently
  /node_modules/,             // node_modules
  /^[A-Z_]+_[A-Z_]+$/,        // environment variable names
];

/**
 * Extract candidate repository-relative paths from markdown text.
 * Looks for:
 *   - markdown links: [text](path)
 *   - inline code: `path`
 *   - bare paths starting with known top-level directories
 *
 * @param {string} content
 * @returns {string[]}      - candidate relative paths
 */
function extractRepoPaths(content) {
  const candidates = new Set();

  // Markdown links: [text](path) where path does not start with http/https
  const linkRe = /\[(?:[^\]]*)\]\(([^)]+)\)/g;
  let m;
  while ((m = linkRe.exec(content)) !== null) {
    const href = m[1].split("#")[0].trim(); // strip anchors
    if (!href) continue;
    if (PATH_SKIP_PATTERNS.some((p) => p.test(href))) continue;
    // Normalize ./ prefix
    const normalized = href.startsWith("./") ? href.slice(2) : href;
    if (normalized.startsWith("../")) continue; // skip upward traversals
    candidates.add(normalized);
  }

  return [...candidates];
}

/**
 * Check that all repository-relative paths referenced in README.md and docs/
 * actually exist in the repository. Returns an array of error strings.
 *
 * @param {string} repoRoot
 * @returns {Promise<string[]>}
 */
export async function checkRepoPathsExist(repoRoot) {
  const errors = [];
  const filesToCheck = [
    path.join(repoRoot, "README.md"),
    ...fs
      .readdirSync(path.join(repoRoot, "docs"))
      .filter((f) => f.endsWith(".md"))
      .map((f) => path.join(repoRoot, "docs", f)),
  ];

  for (const filePath of filesToCheck) {
    if (!fs.existsSync(filePath)) continue;
    const content = fs.readFileSync(filePath, "utf8");
    const relDoc = path.relative(repoRoot, filePath);
    const candidates = extractRepoPaths(content);

    for (const candidate of candidates) {
      // Skip things that obviously aren't repo paths
      if (!candidate || candidate.length < 3) continue;
      // Skip paths that look like markdown-only links (heading anchors)
      if (candidate.startsWith("#")) continue;
      // For links relative to docs/, resolve relative to docs/
      let candidatePath;
      if (relDoc.startsWith("docs/")) {
        candidatePath = path.join(repoRoot, "docs", candidate);
        // If not found there, try relative to repo root
        if (!fs.existsSync(candidatePath)) {
          candidatePath = path.join(repoRoot, candidate);
        }
      } else {
        candidatePath = path.join(repoRoot, candidate);
      }

      if (!fs.existsSync(candidatePath)) {
        errors.push(`${relDoc}: broken repo path reference → ${candidate}`);
      }
    }
  }

  return errors;
}

// ── Main ───────────────────────────────────────────────────────────────────

async function main() {
  const repoRoot = REPO_ROOT;
  const allErrors = [];
  const checks = [
    ["docs/README.md coverage", checkDocsIndexCoverage],
    ["reviewer matrix consistency", checkReviewerMatrixConsistency],
    ["Telegram agent coverage", checkTelegramAgentCoverage],
    ["repo-relative path existence", checkRepoPathsExist],
  ];

  for (const [label, fn] of checks) {
    const errors = await fn(repoRoot);
    if (errors.length > 0) {
      console.error(`\n[FAIL] ${label}:`);
      for (const e of errors) {
        console.error(`  - ${e}`);
      }
      allErrors.push(...errors);
    } else {
      console.log(`[pass] ${label}`);
    }
  }

  if (allErrors.length > 0) {
    console.error(`\ndocs-flow: ${allErrors.length} error(s) found.`);
    process.exit(1);
  } else {
    console.log("\ndocs-flow: all checks passed.");
    process.exit(0);
  }
}

// Run main only when executed directly (not when imported by tests)
const isMain = process.argv[1] === fileURLToPath(import.meta.url);
if (isMain) {
  main().catch((err) => {
    console.error(err);
    process.exit(1);
  });
}