#!/usr/bin/env node
// adam-apply-nudge.mjs — apply-path for `nudge` proposals.
//
// Reads a nudge proposal markdown file, validates the apply gate
// (type == "nudge" AND source_session present), and on success appends one
// entry to ~/.claude/adam/active-nudges.json. The message and the `cue` are
// built DETERMINISTICALLY in code from the proposal frontmatter — the analyst
// does not hand-author the JSON, so the cue (ReContext-style query-conditioning)
// is always populated when a cwd is known, not left to chance.
//
// Frontmatter consumed: type, source_session, cwd (optional — becomes cue.cwd),
// dead_end_count (optional — shapes the message), max_displays (optional, ≥1).
//
// CLI: adam-apply-nudge.mjs <proposal-path> [--home <path>]
// Output: JSON one-liner on stdout: {"status":"applied"|"gated", "reason"|"path"}
// Exit: 0 on apply, 0 on gated, 1 on I/O or parse error.
//
// SKILL.md invokes this in the nudge auto-apply path. No code/memory/skill edits.

import { readFileSync, writeFileSync, existsSync, mkdirSync } from "node:fs";
import { join, dirname } from "node:path";
import { homedir } from "node:os";
import { parseFrontmatter } from "./adam-utils.mjs";

export { parseFrontmatter };

const SEVEN_DAYS_MS = 7 * 86400000;
const DEFAULT_MAX_DISPLAYS = 3;

function parseArgs(argv) {
  const args = { home: null, path: null, help: false };
  for (let i = 0; i < argv.length; i++) {
    const a = argv[i];
    if (a === "--home" && i + 1 < argv.length) args.home = argv[++i];
    else if (a === "--help" || a === "-h") args.help = true;
    else if (!args.path && !a.startsWith("--")) args.path = a;
  }
  return args;
}

export function checkGate(fm) {
  if ((fm.type || "") !== "nudge") {
    return { ok: false, reason: `type != nudge (got: ${fm.type || "<none>"})` };
  }
  if (!fm.source_session) {
    return { ok: false, reason: "source_session missing in frontmatter" };
  }
  return { ok: true };
}

export function buildEntry(fm, now = Date.now()) {
  const cwd = fm.cwd ? String(fm.cwd) : "";
  const base = cwd ? cwd.split("/").filter(Boolean).pop() : "";
  const count = Number(fm.dead_end_count) > 0 ? Number(fm.dead_end_count) : 3;
  const maxDisplays = Number(fm.max_displays) > 0 ? Number(fm.max_displays) : DEFAULT_MAX_DISPLAYS;
  const message = `adam: a previous session hit ${count} dead-ends${base ? ` in ${base}` : ""} — consider a checkpoint before continuing.`;
  const entry = {
    kind: "dead_end_reminder",
    message,
    created_at: now,
    expires_at_ts: now + SEVEN_DAYS_MS,
    max_displays: maxDisplays,
    displays_used: 0,
    source_session: String(fm.source_session || ""),
  };
  // The cue is what makes replay query-conditioned: bind the reminder to the
  // project it came from so it only surfaces there (SessionStart + mid-session).
  if (cwd) entry.cue = { cwd };
  return entry;
}

export function appendNudge(nudgesPath, entry) {
  let arr = [];
  if (existsSync(nudgesPath)) {
    try {
      const parsed = JSON.parse(readFileSync(nudgesPath, "utf8"));
      if (Array.isArray(parsed)) arr = parsed;
    } catch { arr = []; }
  }
  arr.push(entry);
  const dir = dirname(nudgesPath);
  if (!existsSync(dir)) mkdirSync(dir, { recursive: true });
  writeFileSync(nudgesPath, JSON.stringify(arr, null, 2));
  return arr.length;
}

function main() {
  const args = parseArgs(process.argv.slice(2));
  if (args.help || !args.path) {
    process.stdout.write("usage: adam-apply-nudge.mjs <proposal-path> [--home <path>]\n");
    process.exit(args.help ? 0 : 1);
  }
  const claudeHome = args.home || join(homedir(), ".claude");
  const nudgesPath = join(claudeHome, "adam", "active-nudges.json");
  try {
    const content = readFileSync(args.path, "utf8");
    const fm = parseFrontmatter(content);
    const gate = checkGate(fm);
    if (!gate.ok) {
      process.stdout.write(JSON.stringify({ status: "gated", reason: gate.reason }) + "\n");
      process.exit(0);
    }
    const entry = buildEntry(fm);
    const count = appendNudge(nudgesPath, entry);
    process.stdout.write(JSON.stringify({ status: "applied", path: nudgesPath, total: count, cue: entry.cue || null }) + "\n");
    process.exit(0);
  } catch (e) {
    process.stderr.write(`adam-apply-nudge error: ${e.message}\n`);
    process.exit(1);
  }
}

if (import.meta.url === `file://${process.argv[1]}`) {
  main();
}