#!/usr/bin/env node
// profile-loader.mjs — Load and validate ultraplan-local profile YAML files.
//
// Profiles describe which agents, skills, and review regime ultraplan-local
// should use. They live in two locations:
//   - Built-in: plugins/ultraplan-local/profiles/*.yaml
//   - User (M3): .claude/ultraplan-profiles/ and ~/.claude/ultraplan-profiles/
//
// M0 ships with built-in discovery only.
//
// The YAML parser here is intentionally a *limited* subset — enough for the
// profile schema, no more. Supports:
//   - Top-level scalars (string, number, bool, null)
//   - Nested mappings via 2-space indent
//   - Block-style lists ('- item')
//   - Inline lists ('[a, b, c]')
//   - Quoted strings ("..." or '...')
//   - Line comments (# at line start, or after whitespace)
// NOT supported: anchors/aliases, multi-line strings, flow mappings,
// tagged values. If you need those, the schema has drifted — fix the schema.
//
// Pure Node stdlib. No npm dependencies.
//
// CLI:
//   node scripts/profile-loader.mjs list
//   node scripts/profile-loader.mjs load <name>

import { readFile, readdir, stat } from 'node:fs/promises';
import { join, dirname, basename } from 'node:path';
import { fileURLToPath } from 'node:url';
import { argv, exit, stdout, stderr } from 'node:process';

const __dirname = dirname(fileURLToPath(import.meta.url));
const PLUGIN_ROOT = join(__dirname, '..');
const PROFILES_DIR = join(PLUGIN_ROOT, 'profiles');
const AGENTS_DIR = join(PLUGIN_ROOT, 'agents');

// === Required profile fields (validated by validateProfile) ===
export const REQUIRED_FIELDS = ['name', 'description', 'version', 'agents'];
export const REQUIRED_AGENT_KEYS = ['exploration', 'review'];

// =====================================================================
// YAML parser (limited subset)
// =====================================================================

/**
 * Strip a line-trailing comment, respecting quoted strings.
 * Returns the line with any '# ...' suffix removed (when '#' is preceded by
 * whitespace or starts the line) and trailing whitespace trimmed.
 */
export function stripLineComment(line) {
  let inQuote = null;
  for (let i = 0; i < line.length; i++) {
    const ch = line[i];
    if (inQuote) {
      if (ch === '\\') { i++; continue; }
      if (ch === inQuote) inQuote = null;
    } else if (ch === '"' || ch === "'") {
      inQuote = ch;
    } else if (ch === '#') {
      const prev = i === 0 ? ' ' : line[i - 1];
      if (prev === ' ' || prev === '\t' || i === 0) {
        return line.slice(0, i).replace(/\s+$/, '');
      }
    }
  }
  return line.replace(/\s+$/, '');
}

/**
 * Pre-process YAML text into an array of {indent, content} entries.
 * Strips comments and blank lines. Preserves indent for structural parsing.
 */
function preprocessLines(text) {
  const out = [];
  for (const raw of text.split('\n')) {
    const stripped = stripLineComment(raw);
    if (stripped.trim() === '') continue;
    const indent = stripped.length - stripped.trimStart().length;
    out.push({ indent, content: stripped.trim() });
  }
  return out;
}

/**
 * Parse a scalar (right-hand side of `key: value` or list item).
 * Recognises quoted strings, bools, null, numbers, inline lists, otherwise
 * returns the raw string.
 */
export function parseScalar(text) {
  const t = text.trim();
  if (t === '') return null;
  if (t === 'null' || t === '~') return null;
  if (t === 'true') return true;
  if (t === 'false') return false;
  if (t.startsWith('[') && t.endsWith(']')) return parseInlineList(t);
  if (t.startsWith('"') && t.endsWith('"')) return unescapeString(t.slice(1, -1));
  if (t.startsWith("'") && t.endsWith("'")) return t.slice(1, -1);
  // Number? (integer or simple float, no scientific notation needed)
  if (/^-?\d+$/.test(t)) return parseInt(t, 10);
  if (/^-?\d+\.\d+$/.test(t)) return parseFloat(t);
  return t;
}

function unescapeString(s) {
  return s
    .replace(/\\n/g, '\n')
    .replace(/\\t/g, '\t')
    .replace(/\\"/g, '"')
    .replace(/\\\\/g, '\\');
}

/**
 * Parse an inline list like `[a, b, "c d", 1, 2]`.
 * Naive split on commas — does not support nested lists/mappings (not needed).
 */
export function parseInlineList(text) {
  const inner = text.slice(1, -1).trim();
  if (inner === '') return [];
  const items = [];
  let depth = 0;
  let inQuote = null;
  let buf = '';
  for (let i = 0; i < inner.length; i++) {
    const ch = inner[i];
    if (inQuote) {
      buf += ch;
      if (ch === '\\') { buf += inner[++i] ?? ''; continue; }
      if (ch === inQuote) inQuote = null;
      continue;
    }
    if (ch === '"' || ch === "'") { inQuote = ch; buf += ch; continue; }
    if (ch === '[') depth++;
    if (ch === ']') depth--;
    if (ch === ',' && depth === 0) {
      items.push(parseScalar(buf));
      buf = '';
      continue;
    }
    buf += ch;
  }
  if (buf.trim() !== '') items.push(parseScalar(buf));
  return items;
}

/**
 * Parse a block-style list at the given indent. Returns [items, nextIdx].
 * List items are simple scalars only (sufficient for profile schema).
 */
function parseList(lines, idx, indent) {
  const items = [];
  while (idx < lines.length && lines[idx].indent === indent && lines[idx].content.startsWith('- ')) {
    const itemText = lines[idx].content.slice(2).trim();
    items.push(parseScalar(itemText));
    idx++;
  }
  return [items, idx];
}

/**
 * Parse a mapping at the given indent. Returns [obj, nextIdx].
 * A mapping key may be followed by a scalar (same line), a nested mapping,
 * or a block-list (indented more on subsequent lines).
 */
function parseMapping(lines, idx, indent) {
  const result = {};
  while (idx < lines.length && lines[idx].indent === indent) {
    const { content } = lines[idx];
    if (content.startsWith('- ')) break; // not a mapping line
    const colonIdx = findUnquotedColon(content);
    if (colonIdx === -1) {
      throw new Error(`Expected 'key: value' at indent ${indent}, got: ${content}`);
    }
    const key = content.slice(0, colonIdx).trim();
    const rhs = content.slice(colonIdx + 1).trim();
    idx++;
    if (rhs === '') {
      // Look for nested mapping or list at deeper indent
      if (idx < lines.length && lines[idx].indent > indent) {
        const childIndent = lines[idx].indent;
        if (lines[idx].content.startsWith('- ')) {
          const [list, nextIdx] = parseList(lines, idx, childIndent);
          result[key] = list;
          idx = nextIdx;
        } else {
          const [obj, nextIdx] = parseMapping(lines, idx, childIndent);
          result[key] = obj;
          idx = nextIdx;
        }
      } else {
        result[key] = null;
      }
    } else {
      result[key] = parseScalar(rhs);
    }
  }
  return [result, idx];
}

function findUnquotedColon(s) {
  let inQuote = null;
  for (let i = 0; i < s.length; i++) {
    const ch = s[i];
    if (inQuote) {
      if (ch === '\\') { i++; continue; }
      if (ch === inQuote) inQuote = null;
    } else if (ch === '"' || ch === "'") {
      inQuote = ch;
    } else if (ch === ':') {
      return i;
    }
  }
  return -1;
}

/**
 * Public: parse a YAML document into a plain JS object.
 * Throws on malformed input.
 */
export function parseYaml(text) {
  const lines = preprocessLines(text);
  if (lines.length === 0) return {};
  const baseIndent = lines[0].indent;
  if (lines[0].content.startsWith('- ')) {
    const [list] = parseList(lines, 0, baseIndent);
    return list;
  }
  const [obj] = parseMapping(lines, 0, baseIndent);
  return obj;
}

// =====================================================================
// Profile loader
// =====================================================================

/**
 * List all built-in profiles by name (filename minus .yaml).
 * Sorted alphabetically.
 */
export async function listProfiles({ profilesDir = PROFILES_DIR } = {}) {
  let entries;
  try {
    entries = await readdir(profilesDir);
  } catch (err) {
    if (err.code === 'ENOENT') return [];
    throw err;
  }
  const names = entries
    .filter((f) => f.endsWith('.yaml') || f.endsWith('.yml'))
    .map((f) => f.replace(/\.ya?ml$/, ''))
    .sort();
  return names;
}

/**
 * Load and validate a profile by name.
 * Throws if the file is missing, malformed, or fails validation.
 */
export async function loadProfile(name, opts = {}) {
  const profilesDir = opts.profilesDir ?? PROFILES_DIR;
  const agentsDir = opts.agentsDir ?? AGENTS_DIR;
  const path = await resolveProfilePath(name, profilesDir);
  if (!path) {
    const available = await listProfiles({ profilesDir });
    throw new Error(
      `Profile '${name}' not found in ${profilesDir}. Available: ${available.join(', ') || '(none)'}.`
    );
  }
  const text = await readFile(path, 'utf8');
  let parsed;
  try {
    parsed = parseYaml(text);
  } catch (err) {
    throw new Error(`Failed to parse profile '${name}' (${path}): ${err.message}`);
  }
  await validateProfile(parsed, { agentsDir, sourcePath: path });
  return parsed;
}

async function resolveProfilePath(name, profilesDir) {
  const candidates = [join(profilesDir, `${name}.yaml`), join(profilesDir, `${name}.yml`)];
  for (const c of candidates) {
    try {
      const s = await stat(c);
      if (s.isFile()) return c;
    } catch {
      // skip
    }
  }
  return null;
}

/**
 * Validate a parsed profile object against the v1 schema.
 * Throws an Error with all validation issues bundled.
 */
export async function validateProfile(profile, opts = {}) {
  const agentsDir = opts.agentsDir ?? AGENTS_DIR;
  const issues = [];

  if (!profile || typeof profile !== 'object' || Array.isArray(profile)) {
    throw new Error('Profile must be a YAML mapping at the top level.');
  }

  for (const field of REQUIRED_FIELDS) {
    if (!(field in profile)) issues.push(`Missing required field: ${field}`);
  }

  if ('version' in profile && profile.version !== 1) {
    issues.push(`Unsupported profile version ${profile.version} (expected 1).`);
  }

  if ('agents' in profile) {
    const agents = profile.agents;
    if (!agents || typeof agents !== 'object' || Array.isArray(agents)) {
      issues.push('agents must be a mapping with exploration and review keys.');
    } else {
      for (const k of REQUIRED_AGENT_KEYS) {
        if (!(k in agents)) issues.push(`agents.${k} is required.`);
        else if (!Array.isArray(agents[k])) issues.push(`agents.${k} must be a list of agent names.`);
      }
      // Cross-check: every agent name must exist in agents/<name>.md
      const allAgents = [
        ...(Array.isArray(agents.exploration) ? agents.exploration : []),
        ...(Array.isArray(agents.review) ? agents.review : []),
      ];
      const missing = await missingAgents(allAgents, agentsDir);
      for (const m of missing) issues.push(`Unknown agent referenced: ${m} (no ${agentsDir}/${m}.md).`);
    }
  }

  if ('axes' in profile && profile.axes !== null) {
    if (typeof profile.axes !== 'object' || Array.isArray(profile.axes)) {
      issues.push('axes must be a mapping (or omitted).');
    }
  }

  if ('triggers' in profile && profile.triggers !== null) {
    if (typeof profile.triggers !== 'object' || Array.isArray(profile.triggers)) {
      issues.push('triggers must be a mapping (or omitted).');
    } else {
      for (const k of ['keywords', 'nfr_signals']) {
        if (k in profile.triggers && !Array.isArray(profile.triggers[k])) {
          issues.push(`triggers.${k} must be a list.`);
        }
      }
    }
  }

  if ('skills' in profile && profile.skills !== null) {
    if (typeof profile.skills !== 'object' || Array.isArray(profile.skills)) {
      issues.push('skills must be a mapping (or omitted).');
    } else {
      for (const k of ['catalog_filter', 'prefer_layer']) {
        if (k in profile.skills && !Array.isArray(profile.skills[k])) {
          issues.push(`skills.${k} must be a list.`);
        }
      }
    }
  }

  if ('adversarial' in profile && profile.adversarial !== null) {
    const adv = profile.adversarial;
    if (typeof adv !== 'object' || Array.isArray(adv)) {
      issues.push('adversarial must be a mapping (or omitted).');
    } else {
      if ('depth' in adv && !['light', 'standard', 'deep'].includes(adv.depth)) {
        issues.push(`adversarial.depth must be one of light|standard|deep, got: ${adv.depth}`);
      }
      if ('iterations' in adv && (typeof adv.iterations !== 'number' || adv.iterations < 1)) {
        issues.push('adversarial.iterations must be a positive number.');
      }
      if ('blockers_only' in adv && typeof adv.blockers_only !== 'boolean') {
        issues.push('adversarial.blockers_only must be a boolean.');
      }
    }
  }

  if (issues.length > 0) {
    const src = opts.sourcePath ? ` (${opts.sourcePath})` : '';
    throw new Error(`Profile validation failed${src}:\n  - ${issues.join('\n  - ')}`);
  }
  return true;
}

async function missingAgents(names, agentsDir) {
  const missing = [];
  for (const n of names) {
    if (typeof n !== 'string') {
      missing.push(String(n));
      continue;
    }
    try {
      const s = await stat(join(agentsDir, `${n}.md`));
      if (!s.isFile()) missing.push(n);
    } catch {
      missing.push(n);
    }
  }
  return missing;
}

// =====================================================================
// Recommendation helper
// =====================================================================

/**
 * Recommendation threshold used by ultrabrief-local Step 4h. The
 * profile-recommender agent's top-ranked profile must reach this score to
 * be presented as a recommendation; below it, ultrabrief falls back to
 * `default` with an explicit message.
 */
export const RECOMMENDATION_THRESHOLD = 0.7;

/**
 * Decide what to do with a `profile-recommender` agent's ranked output.
 * Returns `{ profile, match, rationale, source }` where:
 *   - `source` is `recommended` (top ≥ threshold), `fallback` (top < threshold
 *     or empty input), or `default-only` (only `default` available).
 *   - `profile` is the chosen profile name.
 *   - `match` is one of `exact | partial | fallback | default-only`.
 *   - `rationale` is a one-sentence explanation suitable for the brief
 *     frontmatter.
 *
 * Rules:
 *   - If `availableProfiles` only contains `default`, return `default-only`.
 *   - If `ranked` is empty/malformed, fall back to `default` with a fallback
 *     rationale.
 *   - Otherwise pick the highest-scoring entry; recommend it only when
 *     `score >= RECOMMENDATION_THRESHOLD`. Below threshold, recommend
 *     `default` with `match: fallback` and the top entry's rationale.
 */
export function selectRecommendation(ranked, opts = {}) {
  const threshold = opts.threshold ?? RECOMMENDATION_THRESHOLD;
  const available = opts.availableProfiles ?? null;

  if (Array.isArray(available) && available.length === 1 && available[0] === 'default') {
    return {
      profile: 'default',
      match: 'default-only',
      rationale: 'Only the default profile is available; recommendation skipped.',
      source: 'default-only',
    };
  }

  if (!Array.isArray(ranked) || ranked.length === 0) {
    return {
      profile: 'default',
      match: 'fallback',
      rationale: 'profile-recommender returned no ranked profiles; using default.',
      source: 'fallback',
    };
  }

  // Find highest-scoring entry. Treat missing/non-numeric scores as 0.
  let top = null;
  for (const entry of ranked) {
    if (!entry || typeof entry.name !== 'string') continue;
    const score = typeof entry.score === 'number' ? entry.score : 0;
    if (top === null || score > (typeof top.score === 'number' ? top.score : 0)) {
      top = { ...entry, score };
    }
  }

  if (top === null) {
    return {
      profile: 'default',
      match: 'fallback',
      rationale: 'profile-recommender output had no usable entries; using default.',
      source: 'fallback',
    };
  }

  if (top.score >= threshold) {
    return {
      profile: top.name,
      match: typeof top.match_quality === 'string' ? top.match_quality : 'partial',
      rationale: typeof top.rationale === 'string' && top.rationale.trim() !== ''
        ? top.rationale
        : `Top-ranked profile (score ${top.score}).`,
      source: 'recommended',
    };
  }

  return {
    profile: 'default',
    match: 'fallback',
    rationale: typeof top.rationale === 'string' && top.rationale.trim() !== ''
      ? `Top score ${top.score} below ${threshold}; ${top.rationale}`
      : `Top score ${top.score} below recommendation threshold ${threshold}.`,
    source: 'fallback',
  };
}

// =====================================================================
// CLI
// =====================================================================

const USAGE = `Usage:
  node scripts/profile-loader.mjs list
  node scripts/profile-loader.mjs load <name>
  node scripts/profile-loader.mjs validate <path-to-yaml>
`;

async function main() {
  const args = argv.slice(2);
  if (args.length === 0 || args[0] === '--help' || args[0] === '-h') {
    stdout.write(USAGE);
    return;
  }
  const cmd = args[0];
  if (cmd === 'list') {
    const names = await listProfiles();
    for (const n of names) stdout.write(n + '\n');
    return;
  }
  if (cmd === 'load') {
    const name = args[1];
    if (!name) { stderr.write('load requires <name>\n'); exit(2); }
    const profile = await loadProfile(name);
    stdout.write(JSON.stringify(profile, null, 2) + '\n');
    return;
  }
  if (cmd === 'validate') {
    const path = args[1];
    if (!path) { stderr.write('validate requires <path>\n'); exit(2); }
    const text = await readFile(path, 'utf8');
    const parsed = parseYaml(text);
    await validateProfile(parsed, { sourcePath: path });
    stdout.write(`OK: ${basename(path)} validates against profile schema v1\n`);
    return;
  }
  stderr.write(USAGE);
  exit(2);
}

// Run CLI only if invoked directly, not when imported.
if (import.meta.url === `file://${process.argv[1]}`) {
  main().catch((err) => {
    stderr.write(`Error: ${err.message}\n`);
    exit(1);
  });
}