#!/usr/bin/env node
// handoff-pipeline.mjs — Deterministic STATE.md helper for graceful-handoff v3.0.
//
// graceful-handoff is now a thin executor of the global "Session Slutt" ritual,
// centred on STATE.md (the three-layer continuity system). The MODEL writes the
// STATE.md content — only it has the session context needed to fill the mandatory
// "👉 NESTE — START HER" block. This script does ONLY the deterministic parts:
//
//   --plan   (default): resolve the nearest STATE.md, classify the remote
//                       (private → tracked, public/open → local-only), gather git
//                       facts. Read-only. Output JSON. The model uses this to write
//                       STATE.md.
//   --commit          : stage STATE.md (ONLY if it is NOT gitignored) plus any
//                       explicit --also paths, then commit. NEVER `git add -A`.
//                       Never pushes (push stays user-triggered — no window gate).
//   --dry-run         : never writes, never touches git.
//
// Why STATE.md must never be auto-committed on a public mirror: a repo whose only
// remote is the public `open/` Forgejo would leak internal state-of-play on push.
// Per the global rule, such repos keep STATE.md local-only (gitignored). The
// authoritative signal here is `git check-ignore STATE.md`; remote_class is the
// advisory that warns on misconfiguration (public repo, STATE.md NOT gitignored).
//
// Output (JSON to stdout): see buildPlan() / commit result below.
// Exit codes: 0 = success (even if errors[] non-empty); 1 = unrecoverable internal error.

import { execSync, execFileSync } from 'node:child_process';
import { existsSync } from 'node:fs';
import { dirname, join, basename } from 'node:path';

// ---------- Argument parsing ----------

function parseArgs(argv) {
  const args = {
    mode: 'plan', // 'plan' | 'commit'
    dryRun: false,
    message: null,
    also: [],
  };
  for (let i = 0; i < argv.length; i++) {
    const a = argv[i];
    if (a === '--plan') args.mode = 'plan';
    else if (a === '--commit') args.mode = 'commit';
    else if (a === '--dry-run') args.dryRun = true;
    else if (a === '--message' || a === '-m') args.message = argv[++i] || null;
    else if (a === '--also') args.also.push(argv[++i]);
    // unknown flags ignored for forward-compat
  }
  return args;
}

// ---------- Git helpers ----------

function gitOk(cmd, opts = {}) {
  try {
    return execSync(cmd, { encoding: 'utf-8', stdio: ['ignore', 'pipe', 'pipe'], ...opts }).trim();
  } catch {
    return null;
  }
}

function gitStatus(cwd) {
  const o = { cwd };
  const branch = gitOk('git branch --show-current', o) || gitOk('git rev-parse --abbrev-ref HEAD', o);
  const porcelain = gitOk('git status --porcelain', o) || '';
  const dirty = porcelain.length > 0;
  let ahead = 0;
  const upstream = gitOk('git rev-parse --abbrev-ref @{u} 2>/dev/null', o);
  if (upstream) {
    const counts = gitOk(`git rev-list --left-right --count ${upstream}...HEAD`, o);
    if (counts) ahead = parseInt(counts.split(/\s+/)[1] || '0', 10);
  }
  const detached = !branch || branch === 'HEAD';
  const dirtyFiles = porcelain.split('\n').filter(Boolean).map(line => line.slice(3));
  return { branch, dirty, ahead, upstream, detached, porcelain, dirtyFiles };
}

function repoRoot(cwd) {
  return gitOk('git rev-parse --show-toplevel', { cwd });
}

// ---------- STATE.md resolution ----------

// Walk from cwd up to (and including) the git repo root, returning the nearest
// existing STATE.md. Mirrors the global session-start hook's "nearest STATE.md
// from cwd up to repo root". If none exists, the target is <repoRoot>/STATE.md.
function resolveStatePath(cwd, root) {
  const stop = root || cwd;
  let cur = cwd;
  for (let i = 0; i < 12; i++) {
    const candidate = join(cur, 'STATE.md');
    if (existsSync(candidate)) return { path: candidate, exists: true };
    if (cur === stop) break;
    const parent = dirname(cur);
    if (parent === cur) break;
    cur = parent;
  }
  return { path: join(stop, 'STATE.md'), exists: false };
}

// ---------- Remote classification ----------

// STATE.md must never reach a public mirror. Private remote → STATE tracked.
// Public (`github.com`, or the `open/` Forgejo mirror) or no remote → local-only.
export function classifyRemote(url) {
  if (!url) return 'none';
  if (/github\.com|github\.io/i.test(url)) return 'public';
  // `open/<repo>` is the public mirror namespace; `ktg/<repo>` etc. is private.
  if (/[:/]open\//i.test(url)) return 'public';
  return 'private';
}

// ---------- Plan (read-only) ----------

function buildPlan(cwd, errors) {
  const root = repoRoot(cwd);
  if (!root) {
    errors.push('ikke et git-repo (git rev-parse --show-toplevel feilet) — kan ikke resolvere STATE.md-sti');
  }
  const base = root || cwd;
  const { path: statePath, exists: stateExists } = resolveStatePath(cwd, base);

  const remoteUrl = gitOk('git remote get-url origin 2>/dev/null', { cwd })
    || gitOk('git remote get-url --all origin 2>/dev/null', { cwd });
  const remoteClass = classifyRemote(remoteUrl);
  const shouldBeLocalOnly = remoteClass !== 'private';

  // Authoritative commit signal: is STATE.md gitignored?
  const stateGitignored = !!gitOk(
    `git check-ignore -- ${JSON.stringify(basename(statePath))}`,
    { cwd: dirname(statePath) }
  );

  const leakWarning = (shouldBeLocalOnly && !stateGitignored)
    ? `STATE.md er IKKE gitignored, men remote er ${remoteClass} (${remoteUrl || 'ingen'}) — `
      + `legg STATE.md i .gitignore for å unngå å lekke intern state-of-play ved push.`
    : null;

  const git = gitStatus(cwd);
  const recentCommits = (gitOk('git log --oneline -8', { cwd }) || '').split('\n').filter(Boolean);

  return {
    mode: 'plan',
    repo_root: root,
    state_path: statePath,
    state_name: basename(dirname(statePath)), // dir holding STATE.md → title "# STATE — <name>"
    state_exists: stateExists,
    state_gitignored: stateGitignored,
    remote_url: remoteUrl,
    remote_class: remoteClass,
    should_be_local_only: shouldBeLocalOnly,
    should_commit_state: !stateGitignored,
    leak_warning: leakWarning,
    git_status: { branch: git.branch, dirty: git.dirty, ahead: git.ahead, detached: git.detached, upstream: git.upstream },
    dirty_files: git.dirtyFiles,
    recent_commits: recentCommits,
    line_budget: 60,
    errors,
  };
}

// ---------- Commit (write) ----------

function generateCommitMessage(statePath, root) {
  const name = root ? basename(root) : basename(dirname(statePath));
  return `docs(${name}): oppdater STATE.md (session handoff)`;
}

function doCommit(cwd, args, errors) {
  const actions = [];
  const root = repoRoot(cwd);
  const base = root || cwd;
  const { path: statePath } = resolveStatePath(cwd, base);

  const git = gitStatus(cwd);
  if (git.detached) {
    errors.push('detached HEAD — hopper over commit (ingen branch å committe på)');
    return { mode: 'commit', actions_taken: actions, errors, git_status: git };
  }

  const stateGitignored = !!gitOk(
    `git check-ignore -- ${JSON.stringify(basename(statePath))}`,
    { cwd: dirname(statePath) }
  );

  // Build the stage list. CRITICAL: never `git add -A` — stage ONLY STATE.md
  // (when it is tracked, i.e. not gitignored) plus any explicit --also paths.
  const stageList = [];
  if (!stateGitignored) {
    if (existsSync(statePath)) stageList.push(statePath);
    else errors.push(`STATE.md finnes ikke på ${statePath} — skriv den før commit`);
  } else {
    actions.push('state-local-only-skipped (STATE.md gitignored — committes ikke)');
  }
  for (const p of args.also) {
    const abs = p.startsWith('/') ? p : join(cwd, p);
    if (existsSync(abs)) stageList.push(abs);
    else errors.push(`--also sti finnes ikke: ${p}`);
  }

  if (stageList.length === 0) {
    actions.push('intet-å-committe (STATE.md gitignored og ingen --also-stier)');
    return { mode: 'commit', actions_taken: actions, errors, git_status: git };
  }

  const message = args.message || generateCommitMessage(statePath, root);

  try {
    execFileSync('git', ['add', '--', ...stageList], { cwd, stdio: ['ignore', 'pipe', 'pipe'] });
    execFileSync('git', ['commit', '-m', message, '--', ...stageList], { cwd, stdio: ['ignore', 'pipe', 'pipe'] });
    actions.push('committed');
  } catch (e) {
    errors.push(`commit feilet: ${(e.stderr || e.message || '').toString().slice(0, 200)}`);
  }

  return { mode: 'commit', actions_taken: actions, committed_paths: stageList, commit_message: message, errors, git_status: git };
}

// ---------- Main ----------

function main() {
  const args = parseArgs(process.argv.slice(2));
  const cwd = process.cwd();
  const errors = [];

  if (args.dryRun) {
    const plan = buildPlan(cwd, errors);
    plan.mode = 'dry-run';
    plan.note = 'dry-run: ingen skriving, ingen git-mutasjon';
    process.stdout.write(JSON.stringify(plan, null, 2) + '\n');
    return;
  }

  let result;
  if (args.mode === 'commit') {
    result = doCommit(cwd, args, errors);
  } else {
    result = buildPlan(cwd, errors);
  }
  process.stdout.write(JSON.stringify(result, null, 2) + '\n');
}

try {
  main();
} catch (e) {
  process.stderr.write(`pipeline-fatal: ${e.message}\n${e.stack}\n`);
  process.exit(1);
}