#!/usr/bin/env node
/**
 * generate-skills.mjs — shared-source generator for agent variants (M3, S-302)
 *
 * Generates every agent-variant directory (`skills/<skill>/<agent>/`) and
 * `pi-package/skills/<skill>/` mirror from canonical sources.  Generated files
 * carry file-type-aware headers; each generated root gets a non-self-referential
 * `.generated-manifest.json`.
 *
 * Usage:
 *   node scripts/generate-skills.mjs          # regenerate everything
 *   pnpm run sync:pi                           # same via pnpm alias
 *
 * Exported helpers (used by verify-generated.mjs and tests):
 *   detectFileType(filePath) → string
 *   applyHeader(content, fileType, canonicalHint) → string
 *   makePackageJsonContent(sourcePkg, skillName, agentName) → object
 *   getGeneratedRoots(repoRoot?) → string[]
 *   buildManifest(generatedRootAbs, generatedRootRel) → Promise<object>
 *   generateSkills(repoRoot, options?) → Promise<{generatedRoots: string[]}>
 */

import {
  lstat,
  mkdir,
  readdir,
  readFile,
  rm,
  writeFile,
} from "node:fs/promises";
import crypto from "node:crypto";
import path from "node:path";
import { pathToFileURL } from "node:url";

const REPO_ROOT = path.resolve(path.dirname(new URL(import.meta.url).pathname), "..");

// ── Constants ──────────────────────────────────────────────────────────────

const MANIFEST_SCHEMA =
  "https://ai-coding-skills.dev/schemas/generated-manifest/v1.json";
const MANIFEST_GENERATOR = "scripts/generate-skills.mjs";
const MANIFEST_FILENAME = ".generated-manifest.json";

const AGENTS = ["claude-code", "codex", "cursor", "opencode", "pi"];

/**
 * Canonical list of all generated roots, relative to repo root.
 * Verifier uses this to know which directories to walk.
 */
const GENERATED_ROOTS = [
  // atlassian agent variants
  "skills/atlassian/claude-code",
  "skills/atlassian/codex",
  "skills/atlassian/cursor",
  "skills/atlassian/opencode",
  "skills/atlassian/pi",
  // web-automation agent variants
  "skills/web-automation/claude-code",
  "skills/web-automation/codex",
  "skills/web-automation/cursor",
  "skills/web-automation/opencode",
  "skills/web-automation/pi",
  // create-plan agent variants
  "skills/create-plan/claude-code",
  "skills/create-plan/codex",
  "skills/create-plan/cursor",
  "skills/create-plan/opencode",
  "skills/create-plan/pi",
  // do-task agent variants
  "skills/do-task/claude-code",
  "skills/do-task/codex",
  "skills/do-task/cursor",
  "skills/do-task/opencode",
  "skills/do-task/pi",
  // implement-plan agent variants
  "skills/implement-plan/claude-code",
  "skills/implement-plan/codex",
  "skills/implement-plan/cursor",
  "skills/implement-plan/opencode",
  "skills/implement-plan/pi",
  // reviewer-runtime pi variant
  "skills/reviewer-runtime/pi",
  // pi-package mirrors
  "pi-package/skills/atlassian",
  "pi-package/skills/create-plan",
  "pi-package/skills/do-task",
  "pi-package/skills/implement-plan",
  "pi-package/skills/web-automation",
];

// ── File-type detection ────────────────────────────────────────────────────

/**
 * Classify a file path into a header policy category.
 * @param {string} filePath - Relative or absolute path to the file.
 * @returns {'markdown'|'shell'|'ts'|'js'|'json'|'yaml'|'jsonc'|'unknown'}
 */
export function detectFileType(filePath) {
  const base = path.basename(filePath);
  const ext = path.extname(base).toLowerCase();

  if (ext === ".md") return "markdown";
  if (ext === ".sh") return "shell";
  if (ext === ".ts") return "ts";
  if (ext === ".js") return "js";
  if (ext === ".jsonc") return "jsonc";
  if (ext === ".json") return "json";
  if (ext === ".yaml" || ext === ".yml") return "yaml";
  return "unknown";
}

// ── Header insertion ──────────────────────────────────────────────────────

const HEADER_MSG = (hint) =>
  `⚠️ GENERATED FILE – do not edit directly. Edit the canonical source in ${hint} and run \`pnpm run sync:pi\`.`;

/**
 * Insert a file-type-aware generated-file header into content.
 *
 * Policy:
 *   markdown  → HTML comment after YAML front matter (or at top if no front matter)
 *   shell     → # comment after shebang (never before it)
 *   ts/js     → // comment at top
 *   jsonc     → // comment at top
 *   yaml      → # comment at top  (pnpm-lock.yaml skipped by caller)
 *   json      → no header (recorded in .generated-manifest.json)
 *   unknown   → no header
 *
 * @param {string} content - Original file content.
 * @param {string} fileType - Output of detectFileType().
 * @param {string} canonicalHint - Human-readable hint to canonical source location.
 * @returns {string} Content with header inserted, or original if no header applies.
 */
export function applyHeader(content, fileType, canonicalHint) {
  const msg = HEADER_MSG(canonicalHint);

  switch (fileType) {
    case "markdown": {
      // Insert HTML comment after YAML front matter closing ---, or at top
      if (content.startsWith("---\n")) {
        const closingIdx = content.indexOf("\n---\n", 4);
        if (closingIdx !== -1) {
          const after = closingIdx + 5; // length of "\n---\n"
          const before = content.slice(0, after);
          const rest = content.slice(after);
          // Ensure the comment is on its own line, with a blank line before/after
          return `${before}\n<!-- ${msg} -->\n${rest}`;
        }
      }
      return `<!-- ${msg} -->\n${content}`;
    }

    case "shell": {
      // Insert # comment AFTER shebang line (never before it)
      const lines = content.split("\n");
      if (lines[0].startsWith("#!")) {
        return [lines[0], `# ${msg}`, ...lines.slice(1)].join("\n");
      }
      return `# ${msg}\n${content}`;
    }

    case "ts":
    case "js":
    case "jsonc": {
      // Insert after shebang if present (TypeScript requires #! on line 1)
      const lines = content.split("\n");
      if (lines[0].startsWith("#!")) {
        return [lines[0], `// ${msg}`, ...lines.slice(1)].join("\n");
      }
      return `// ${msg}\n${content}`;
    }

    case "yaml": {
      return `# ${msg}\n${content}`;
    }

    case "json":
    case "unknown":
    default:
      return content;
  }
}

// ── package.json transformation ───────────────────────────────────────────

/**
 * Produce a modified package.json object with a unique scoped name and
 * `"private": true` for an agent-variant generated root.
 *
 * @param {object} sourcePkg - Parsed source package.json object.
 * @param {string} skillName - Skill identifier (e.g. "atlassian").
 * @param {string} agentName - Agent identifier (e.g. "claude-code").
 * @returns {object} New object (source is not mutated).
 */
export function makePackageJsonContent(sourcePkg, skillName, agentName) {
  return {
    ...sourcePkg,
    name: `@ai-coding-skills/${skillName}-${agentName}`,
    private: true,
  };
}

// ── Generated-root list ───────────────────────────────────────────────────

/**
 * Return the authoritative list of generated roots as repo-relative paths.
 * Callers (verify-generated.mjs) use this to know which directories to walk.
 *
 * @returns {string[]} Sorted array of relative paths.
 */
export function getGeneratedRoots() {
  return [...GENERATED_ROOTS];
}

// ── Manifest construction ─────────────────────────────────────────────────

/**
 * Walk a directory recursively and return all file paths (abs).
 * Skips node_modules.
 */
async function walkDir(dir) {
  const results = [];
  let entries;
  try {
    entries = await readdir(dir, { withFileTypes: true });
  } catch {
    return results;
  }
  for (const entry of entries) {
    if (entry.name === "node_modules") continue;
    const full = path.join(dir, entry.name);
    if (entry.isDirectory()) {
      const sub = await walkDir(full);
      results.push(...sub);
    } else if (entry.isFile()) {
      results.push(full);
    }
  }
  return results;
}

/**
 * Build a .generated-manifest.json object for a generated root.
 *
 * The manifest lists every file in the generated root EXCEPT itself.
 * Files are sorted by relative path for stable canonical serialization.
 *
 * @param {string} generatedRootAbs - Absolute path to the generated root directory.
 * @param {string} generatedRootRel - Repo-relative path (e.g. "skills/create-plan/pi").
 * @returns {Promise<object>} Manifest object (not yet serialized to disk).
 */
export async function buildManifest(generatedRootAbs, generatedRootRel) {
  const allFiles = await walkDir(generatedRootAbs);
  const entries = [];

  for (const absPath of allFiles) {
    const relPath = path.relative(generatedRootAbs, absPath).replace(/\\/g, "/");

    // Non-self-referential: the manifest never lists itself
    if (relPath === MANIFEST_FILENAME) continue;

    const contentBuf = await readFile(absPath);
    const sha256 = crypto.createHash("sha256").update(contentBuf).digest("hex");

    const st = await lstat(absPath);
    const mode = (st.mode & 0o777).toString(8).padStart(3, "0");

    entries.push({
      path: relPath,
      kind: "file",
      mode,
      sha256,
    });
  }

  entries.sort((a, b) => a.path.localeCompare(b.path));

  return {
    $schema: MANIFEST_SCHEMA,
    generator: MANIFEST_GENERATOR,
    generatedRoot: generatedRootRel,
    files: entries,
  };
}

// ── Core generation helpers ───────────────────────────────────────────────

/**
 * Copy a single file from source to destination, inserting a header.
 * Skips header for:
 *   - pnpm-lock.yaml (managed by pnpm, would be stripped on next install)
 *   - JSON files (per header policy, no in-file header)
 *   - node_modules (never copied)
 */
async function copyWithHeader(srcAbs, dstAbs, canonicalHint) {
  const basename = path.basename(srcAbs);
  // Skip pnpm-lock.yaml header (pnpm regenerates without comment)
  const skipHeader = basename === "pnpm-lock.yaml";

  const raw = await readFile(srcAbs, "utf8");
  const fileType = skipHeader ? "unknown" : detectFileType(srcAbs);
  const content = applyHeader(raw, fileType, canonicalHint);

  await mkdir(path.dirname(dstAbs), { recursive: true });
  await writeFile(dstAbs, content, "utf8");
}

/**
 * Recursively copy a directory tree, adding headers to text files.
 */
async function copyDirWithHeaders(srcDir, dstDir, canonicalHint) {
  const entries = await readdir(srcDir, { withFileTypes: true });
  await mkdir(dstDir, { recursive: true });

  for (const entry of entries) {
    if (entry.name === "node_modules") continue;
    const src = path.join(srcDir, entry.name);
    const dst = path.join(dstDir, entry.name);

    if (entry.isDirectory()) {
      await copyDirWithHeaders(src, dst, canonicalHint);
    } else if (entry.isFile()) {
      await copyWithHeader(src, dst, canonicalHint);
    }
  }
}

/**
 * Write a .generated-manifest.json file into a generated root.
 */
async function writeManifest(generatedRootAbs, generatedRootRel) {
  const manifest = await buildManifest(generatedRootAbs, generatedRootRel);
  const dstPath = path.join(generatedRootAbs, MANIFEST_FILENAME);
  await writeFile(dstPath, JSON.stringify(manifest, null, 2) + "\n", "utf8");
}

// ── Skill-family generators ───────────────────────────────────────────────

/**
 * Generate one agent variant for a "skills-only" skill
 * (create-plan, do-task, implement-plan).
 *
 * Canonical source: skills/<skill>/_source/<agent>/
 * Generated root:   skills/<skill>/<agent>/
 *
 * @param {string} writeRoot - Root directory to write output into (defaults to repoRoot).
 */
async function generateSkillOnlyVariant(repoRoot, writeRoot, skillName, agentName, generatedRootRel) {
  const sourceDir = path.join(repoRoot, "skills", skillName, "_source", agentName);
  const targetDir = path.join(writeRoot, generatedRootRel);
  const canonicalHint = `skills/${skillName}/_source/${agentName}/`;

  // Clear previous generated content (preserve node_modules if any)
  await clearGeneratedRoot(targetDir);

  // Copy all files from source with headers
  await copyDirWithHeaders(sourceDir, targetDir, canonicalHint);

  // Write manifest
  await writeManifest(targetDir, generatedRootRel);
}

/**
 * Generate one agent variant for a "scripts+skill" skill
 * (atlassian, web-automation).
 *
 * For atlassian:
 *   - SKILL.md from skills/atlassian/_source/<agent>/SKILL.md
 *   - scripts/* from skills/atlassian/shared/scripts/
 *     (only src/, tsconfig.json, pnpm-lock.yaml — not tests/ or scripts/sync-*)
 *
 * For web-automation:
 *   - SKILL.md from skills/web-automation/_source/<agent>/SKILL.md
 *   - scripts/* from skills/web-automation/shared/
 *
 * @param {string} [packageAgentName] - Override the agent name used only for the
 *   package.json `name` field.  Defaults to `agentName`.  Use this to give
 *   pi-package mirrors a distinct name (e.g. "pi-mirror") so workspace package
 *   names are unique even when two roots share the same source agent.
 */
async function generateScriptsSkillVariant(
  repoRoot,
  writeRoot,
  skillName,
  agentName,
  generatedRootRel,
  config,
  packageAgentName,
) {
  const targetDir = path.join(writeRoot, generatedRootRel);
  await clearGeneratedRoot(targetDir);

  // 1. Copy SKILL.md from per-agent canonical source
  const skillMdSrc = path.join(repoRoot, "skills", skillName, "_source", agentName, "SKILL.md");
  const skillMdDst = path.join(targetDir, "SKILL.md");
  const skillMdHint = `skills/${skillName}/_source/${agentName}/SKILL.md`;
  await copyWithHeader(skillMdSrc, skillMdDst, skillMdHint);

  // 2. Copy scripts
  const scriptsTargetDir = path.join(targetDir, "scripts");
  await mkdir(scriptsTargetDir, { recursive: true });

  const canonicalScripts = path.join(repoRoot, config.canonicalScripts);
  const scriptsHint = `${config.canonicalScripts}/`;

  for (const entry of config.scriptFiles) {
    const srcPath = path.join(canonicalScripts, entry);
    const dstPath = path.join(scriptsTargetDir, entry); // scriptsTargetDir already uses writeRoot

    // Check if source exists
    let st;
    try {
      st = await lstat(srcPath);
    } catch {
      continue; // skip if file doesn't exist in canonical
    }

    if (st.isDirectory()) {
      await copyDirWithHeaders(srcPath, dstPath, scriptsHint);
    } else {
      await copyWithHeader(srcPath, dstPath, scriptsHint);
    }
  }

  // 3. Generate modified package.json
  const srcPkgPath = path.join(canonicalScripts, "package.json");
  const srcPkg = JSON.parse(await readFile(srcPkgPath, "utf8"));

  let targetPkg = makePackageJsonContent(srcPkg, skillName, packageAgentName ?? agentName);

  // For atlassian variants, strip test/sync scripts (not in agent variants)
  if (skillName === "atlassian") {
    const agentScripts = {};
    for (const [k, v] of Object.entries(targetPkg.scripts ?? {})) {
      if (k !== "test" && k !== "sync:agents") agentScripts[k] = v;
    }
    targetPkg = { ...targetPkg, scripts: agentScripts };
  }

  const dstPkgPath = path.join(scriptsTargetDir, "package.json");
  await writeFile(dstPkgPath, JSON.stringify(targetPkg, null, 2) + "\n", "utf8");

  // 4. Write manifest
  await writeManifest(targetDir, generatedRootRel);
}

/**
 * Generate the reviewer-runtime pi variant from the non-Pi canonical scripts.
 *
 * Canonical source: skills/reviewer-runtime/{run-review.sh,notify-telegram.sh}
 * Generated root:   skills/reviewer-runtime/pi/
 *
 * The pi variant is byte-identical to the canonical except for:
 *   - A generated # comment after the shebang (replaces old "keep in sync" comment)
 *
 * @param {string} writeRoot - Root directory to write output into (defaults to repoRoot).
 */
async function generateReviewerRuntimePi(repoRoot, writeRoot) {
  const srcDir = path.join(repoRoot, "skills", "reviewer-runtime");
  const dstDir = path.join(writeRoot, "skills", "reviewer-runtime", "pi");
  const canonicalHint = "skills/reviewer-runtime/";

  // Clear old generated content (preserve tests/ which is canonical)
  await clearGeneratedRoot(dstDir);

  for (const fname of ["run-review.sh", "notify-telegram.sh"]) {
    const srcPath = path.join(srcDir, fname);
    const dstPath = path.join(dstDir, fname);

    const raw = await readFile(srcPath, "utf8");
    let content = applyHeader(raw, "shell", `${canonicalHint}${fname}`);

    await mkdir(path.dirname(dstPath), { recursive: true });
    await writeFile(dstPath, content, "utf8");

    // Preserve executable bit
    const st = await lstat(srcPath);
    if (st.mode & 0o100) {
      const { chmod } = await import("node:fs/promises");
      await chmod(dstPath, 0o755);
    }
  }

  // Write manifest (generatedRootRel is always relative to repo root, not writeRoot)
  await writeManifest(dstDir, "skills/reviewer-runtime/pi");
}

/**
 * Clear generated content in a root, preserving:
 *   - node_modules (installed by pnpm) — at any depth
 *   - .generated-manifest.json (will be rewritten after generation)
 *
 * Subdirectories are always recursed into before removal so that
 * node_modules trees nested at any depth (e.g. scripts/node_modules inside
 * atlassian or web-automation variants) are preserved.
 */
async function clearGeneratedRoot(rootDir) {
  let entries;
  try {
    entries = await readdir(rootDir, { withFileTypes: true });
  } catch {
    return; // dir doesn't exist yet — nothing to clear
  }

  for (const entry of entries) {
    if (entry.name === "node_modules") continue;
    if (entry.name === MANIFEST_FILENAME) continue;
    const fullPath = path.join(rootDir, entry.name);
    if (entry.isDirectory()) {
      // Always recurse so node_modules at any depth is preserved.
      await clearGeneratedRoot(fullPath);
      // Remove the directory only if nothing protected remains inside it.
      const remaining = await readdir(fullPath).catch(() => []);
      if (remaining.length === 0) {
        await rm(fullPath, { force: true });
      }
    } else {
      await rm(fullPath, { force: true });
    }
  }
}

// ── Skill configurations ──────────────────────────────────────────────────

const SCRIPTS_SKILL_CONFIGS = {
  atlassian: {
    canonicalScripts: "skills/atlassian/shared/scripts",
    // Files to copy from canonicalScripts into each agent's scripts/ dir
    scriptFiles: ["src", "tsconfig.json", "pnpm-lock.yaml"],
  },
  "web-automation": {
    canonicalScripts: "skills/web-automation/shared",
    scriptFiles: [
      "auth.ts",
      "browse.ts",
      "check-install.js",
      "extract.js",
      "flow.ts",
      "lib",
      "scan-local-app.ts",
      "scrape.ts",
      "test-full.ts",
      "test-minimal.ts",
      "test-profile.ts",
      "tsconfig.json",
      "turndown-plugin-gfm.d.ts",
      "pnpm-lock.yaml",
    ],
  },
};

// ── Main generator ────────────────────────────────────────────────────────

/**
 * Regenerate all agent variants from canonical sources.
 *
 * @param {string} repoRoot - Absolute path to repo root (canonical sources are read from here).
 * @param {object} [options]
 * @param {boolean} [options.dryRun] - If true, don't write files (future use).
 * @param {string} [options.targetRoot] - Write generated output here instead of `repoRoot`.
 *   Canonical sources are always read from `repoRoot`.  Use this to generate into a
 *   temp directory for drift detection without modifying on-disk files.
 * @returns {Promise<{generatedRoots: string[]}>}
 */
export async function generateSkills(repoRoot = REPO_ROOT, options = {}) {
  const { dryRun = false, targetRoot } = options;
  const writeRoot = targetRoot ?? repoRoot;
  if (dryRun) {
    return { generatedRoots: GENERATED_ROOTS };
  }

  const skillOnlySkills = ["create-plan", "do-task", "implement-plan"];

  // 1. Generate skill-only skills (create-plan, do-task, implement-plan)
  for (const skillName of skillOnlySkills) {
    for (const agentName of AGENTS) {
      const rootRel = `skills/${skillName}/${agentName}`;
      await generateSkillOnlyVariant(repoRoot, writeRoot, skillName, agentName, rootRel);
    }
    // pi-package mirror (same source as pi variant)
    const piPackageRel = `pi-package/skills/${skillName}`;
    await generateSkillOnlyVariant(repoRoot, writeRoot, skillName, "pi", piPackageRel);
  }

  // 2. Generate scripts skills (atlassian, web-automation)
  for (const [skillName, config] of Object.entries(SCRIPTS_SKILL_CONFIGS)) {
    for (const agentName of AGENTS) {
      const rootRel = `skills/${skillName}/${agentName}`;
      await generateScriptsSkillVariant(repoRoot, writeRoot, skillName, agentName, rootRel, config);
    }
    // pi-package mirror: same source as pi variant but a distinct package name
    // ("pi-mirror" suffix) so the workspace has no duplicate package names.
    const piPackageRel = `pi-package/skills/${skillName}`;
    await generateScriptsSkillVariant(repoRoot, writeRoot, skillName, "pi", piPackageRel, config, "pi-mirror");
  }

  // 3. Generate reviewer-runtime pi variant
  await generateReviewerRuntimePi(repoRoot, writeRoot);

  return { generatedRoots: GENERATED_ROOTS };
}

// ── CLI entry point ────────────────────────────────────────────────────────

if (import.meta.url === pathToFileURL(process.argv[1]).href) {
  try {
    const result = await generateSkills(REPO_ROOT);
    console.log(
      `Generated ${result.generatedRoots.length} roots from canonical sources.`,
    );
    process.exit(0);
  } catch (err) {
    console.error("generate-skills: fatal error:", err.message ?? err);
    process.exit(1);
  }
}