// lib/profiles/resolver.mjs
// Profile resolution layer (v4.1 SC #5-#9; v5.1.1 brief-signal extension).
//
// Locked interface contract (per brief Preferences):
//   loadProfile(name) → ProfileObject
//     - Reads lib/profiles/<name>.yaml or custom voyage-profiles/<name>.yaml.
//     - Throws Error (cause: PROFILE_NOT_FOUND) when not found.
//     - Returns parsed object with phase_models flattened to {brief: 'sonnet', ...}
//       (object form for downstream JSON-stats; conversion from YAML list-of-dicts).
//
//   resolveProfile(argv, env) → {profile, profile_source}
//     - Resolution order: --profile flag > VOYAGE_PROFILE env > 'premium' default.
//     - profile_source: 'flag' | 'env' | 'default'.
//
//   resolveTrekcontinueProfile(planPath, argv) → {profile, profile_source}
//     - --profile flag in argv wins with 'flag'.
//     - Otherwise reads plan.md frontmatter via parseDocument; returns
//       plan-frontmatter `profile` field with 'inheritance'.
//     - If flag overrides inheritance, console.error emits an advisory.
//     - For v4.0-style plans without `profile:` field, returns 'default' premium.
//
//   validateProfileFile(path) → Result
//     - Thin wrapper around validateProfile from profile-validator.mjs.
//
//   resolvePhaseModel(phase, briefPath, argv, env)
//                                              → {model, source}  (v5.1.1 ADDITIVE)
//     - Highest-priority lookup step: brief.phase_signals[phase].model (source='brief-signal').
//     - Falls through via resolveProfile (flag → env → default) when brief signal absent.
//     - Never throws; ENOENT/parse failures degrade silently to the next step.
//     - phase ∈ {brief, continue} (outside PHASE_SIGNAL_PHASES) always falls through.
//     - Controls ORCHESTRATOR model only. Sub-agents read agents/*.md frontmatter
//       directly; commands must inject {resolved model} into Agent-tool spawn sites
//       for sub-agents to honor brief signals. See feedback_voyage_opus_always.md.
//
// Custom.yaml lookup order: <repo-root>/voyage-profiles/<name>.yaml > ~/.claude/voyage-profiles/<name>.yaml
// Both attempted paths included in error message on miss (HIGH-risk-mitigering).

import { readFileSync, existsSync } from 'node:fs';
import { join, dirname, resolve } from 'node:path';
import { fileURLToPath } from 'node:url';
import { homedir } from 'node:os';
import { parseDocument } from '../util/frontmatter.mjs';
import { validateProfile } from '../validators/profile-validator.mjs';
import { resolvePhaseSignal } from './phase-signal-resolver.mjs';

const __dirname = dirname(fileURLToPath(import.meta.url));
const BUILTIN_PROFILES_DIR = __dirname; // lib/profiles/
const BUILTIN_NAMES = new Set(['economy', 'balanced', 'premium']);

/**
 * Resolve the path to a profile file.
 * Built-in profiles: lib/profiles/<name>.yaml
 * Custom profiles: <repo-root>/voyage-profiles/<name>.yaml > ~/.claude/voyage-profiles/<name>.yaml
 *
 * @returns {{path: string|null, attempted: string[]}}
 */
export function findProfilePath(name, opts = {}) {
  const cwd = opts.cwd || process.cwd();
  const home = opts.home || homedir();
  const attempted = [];

  if (BUILTIN_NAMES.has(name)) {
    const builtinPath = join(BUILTIN_PROFILES_DIR, `${name}.yaml`);
    attempted.push(builtinPath);
    if (existsSync(builtinPath)) return { path: builtinPath, attempted };
  }

  // Custom: repo-root first, then home
  const repoCustom = join(cwd, 'voyage-profiles', `${name}.yaml`);
  attempted.push(repoCustom);
  if (existsSync(repoCustom)) return { path: repoCustom, attempted };

  const homeCustom = join(home, '.claude', 'voyage-profiles', `${name}.yaml`);
  attempted.push(homeCustom);
  if (existsSync(homeCustom)) return { path: homeCustom, attempted };

  return { path: null, attempted };
}

/**
 * Flatten phase_models list-of-dicts to object form: {brief: 'sonnet', research: 'opus', ...}
 */
function flattenPhaseModels(list) {
  const out = {};
  if (!Array.isArray(list)) return out;
  for (const entry of list) {
    if (entry && typeof entry === 'object' && typeof entry.phase === 'string' && typeof entry.model === 'string') {
      out[entry.phase] = entry.model;
    }
  }
  return out;
}

/**
 * Load and parse a profile file by name.
 * @param {string} name
 * @param {{cwd?: string, home?: string}} [opts]
 * @returns {{name: string, profile_version: string, phase_models: object, parallel_agents_min: number, parallel_agents_max: number, external_research_enabled: boolean, brief_reviewer_iter_cap: number, _path: string}}
 * @throws {Error} cause: PROFILE_NOT_FOUND | PROFILE_PARSE_ERROR
 */
export function loadProfile(name, opts = {}) {
  const { path, attempted } = findProfilePath(name, opts);
  if (!path) {
    const err = new Error(
      `Profile "${name}" not found. Attempted paths:\n  - ${attempted.join('\n  - ')}`,
    );
    err.cause = 'PROFILE_NOT_FOUND';
    err.attempted = attempted;
    throw err;
  }

  let text;
  try { text = readFileSync(path, 'utf-8'); }
  catch (e) {
    const err = new Error(`Cannot read profile "${name}" at ${path}: ${e.message}`);
    err.cause = 'PROFILE_READ_ERROR';
    throw err;
  }

  const doc = parseDocument(text);
  if (!doc.valid) {
    const err = new Error(`Profile "${name}" parse error: ${doc.errors[0]?.message || 'unknown'}`);
    err.cause = 'PROFILE_PARSE_ERROR';
    throw err;
  }

  const fm = doc.parsed.frontmatter || {};
  return {
    name: fm.name,
    profile_version: fm.profile_version,
    phase_models: flattenPhaseModels(fm.phase_models),
    parallel_agents_min: fm.parallel_agents_min,
    parallel_agents_max: fm.parallel_agents_max,
    external_research_enabled: fm.external_research_enabled,
    brief_reviewer_iter_cap: fm.brief_reviewer_iter_cap,
    _path: path,
  };
}

/**
 * Resolve profile name from argv + env + default.
 * Order: --profile flag > VOYAGE_PROFILE env > 'premium'.
 *
 * @param {{flags?: object} | string[]} argv  Either parsed argv or a flags-object.
 * @param {object} [env]
 * @returns {{profile: string, profile_source: 'flag'|'env'|'default'}}
 */
export function resolveProfile(argv, env = process.env) {
  const flags = (argv && typeof argv === 'object' && argv.flags) ? argv.flags : (argv || {});
  if (typeof flags['--profile'] === 'string' && flags['--profile'].length > 0) {
    return { profile: flags['--profile'], profile_source: 'flag' };
  }
  if (typeof env.VOYAGE_PROFILE === 'string' && env.VOYAGE_PROFILE.length > 0) {
    return { profile: env.VOYAGE_PROFILE, profile_source: 'env' };
  }
  return { profile: 'premium', profile_source: 'default' };
}

/**
 * Resolve profile for /trekcontinue: prefers explicit flag, falls back to plan
 * frontmatter (inheritance), then 'premium' default if plan has no profile field.
 *
 * @param {string} planPath  Path to plan.md
 * @param {{flags?: object} | string[]} argv
 * @param {{env?: object, console?: Console}} [opts]
 * @returns {{profile: string, profile_source: 'flag'|'inheritance'|'default'}}
 */
export function resolveTrekcontinueProfile(planPath, argv, opts = {}) {
  const env = opts.env || process.env;
  const con = opts.console || console;

  const flags = (argv && typeof argv === 'object' && argv.flags) ? argv.flags : (argv || {});
  const flagProfile = (typeof flags['--profile'] === 'string' && flags['--profile'].length > 0)
    ? flags['--profile'] : null;

  // Read plan-frontmatter to detect inheritance
  let planProfile = null;
  if (planPath && existsSync(planPath)) {
    try {
      const text = readFileSync(planPath, 'utf-8');
      const doc = parseDocument(text);
      if (doc.valid) {
        const fm = doc.parsed.frontmatter || {};
        if (typeof fm.profile === 'string' && fm.profile.length > 0) {
          planProfile = fm.profile;
        }
      }
    } catch {
      // swallow — degrades gracefully to default
    }
  }

  if (flagProfile) {
    if (planProfile && planProfile !== flagProfile) {
      con.error(`[voyage] profile inheritance overridden by --profile flag: ${planProfile} → ${flagProfile}`);
    }
    return { profile: flagProfile, profile_source: 'flag' };
  }

  if (planProfile) {
    return { profile: planProfile, profile_source: 'inheritance' };
  }

  // v4.0-style plan without profile: default to premium
  return { profile: 'premium', profile_source: 'default' };
}

/**
 * Validate a profile YAML file.
 * Thin wrapper for locked-interface compatibility.
 */
export function validateProfileFile(path, opts = {}) {
  return validateProfile(path, opts);
}

/**
 * Resolve the model for a specific pipeline phase, applying brief-signal override
 * as the new highest-priority lookup step (v5.1.1).
 *
 * @param {string} phase            One of brief|research|plan|execute|review|continue
 * @param {string|null} briefPath   Absolute or repo-relative path to brief.md, or null
 * @param {string[]|object} argv    Full process.argv array OR parsed flags object
 * @param {object} [env]            Environment-variable record (defaults to process.env)
 * @returns {{model: string, source: 'brief-signal'|'flag'|'env'|'default'}}
 *
 * Error handling contract:
 *  - Never throws. Any failure (ENOENT on briefPath, malformed YAML, missing
 *    phase_signals entry, missing model field) silently falls through.
 *  - Treats unreadable briefPath as equivalent to briefPath=null.
 *  - Returns the fallthrough resolution when phase ∈ {brief, continue} (not in
 *    PHASE_SIGNAL_PHASES).
 *
 * Controls ORCHESTRATOR model only. Sub-agents read agents/*.md frontmatter
 * directly; commands must inject {resolved model} at Agent-tool spawn sites.
 */
export function resolvePhaseModel(phase, briefPath, argv, env = process.env) {
  // Step 1: brief-signal lookup
  if (typeof briefPath === 'string' && briefPath.length > 0 && existsSync(briefPath)) {
    let fm = null;
    try {
      const text = readFileSync(briefPath, 'utf-8');
      const doc = parseDocument(text);
      if (doc && doc.valid) fm = doc.parsed && doc.parsed.frontmatter;
    } catch {
      // swallow — degrade gracefully to fallthrough
    }
    if (fm) {
      const signal = resolvePhaseSignal(fm, phase);
      if (signal && typeof signal.model === 'string' && signal.model.length > 0) {
        return { model: signal.model, source: 'brief-signal' };
      }
    }
  }

  // Step 2+3+4: fall through via existing resolveProfile chain
  // (flag → env → default), then index into profile.phase_models[phase].
  // Normalize argv: resolveProfile expects flags-object form. When called with
  // a raw process.argv-style array, extract --profile here.
  let normalizedFlags = argv;
  if (Array.isArray(argv)) {
    const idx = argv.indexOf('--profile');
    normalizedFlags = (idx >= 0 && idx + 1 < argv.length)
      ? { '--profile': argv[idx + 1] }
      : {};
  }
  const { profile, profile_source } = resolveProfile(normalizedFlags, env);
  let phaseModels = {};
  try {
    const p = loadProfile(profile);
    phaseModels = p.phase_models || {};
  } catch {
    // Unknown profile → fall back to premium
    try {
      const p = loadProfile('premium');
      phaseModels = p.phase_models || {};
    } catch {
      phaseModels = {};
    }
  }
  const model = phaseModels[phase] || 'opus';
  return { model, source: profile_source };
}

// CLI shim — invoked by commands/trek*.md via Bash.
// Usage: node lib/profiles/resolver.mjs --resolve-phase-model --phase plan --brief-path foo.md --json
if (import.meta.url === `file://${process.argv[1]}`) {
  const args = process.argv.slice(2);
  if (args.includes('--resolve-phase-model')) {
    const getArg = (name) => {
      const i = args.indexOf(name);
      return i >= 0 && i + 1 < args.length ? args[i + 1] : null;
    };
    const phase = getArg('--phase');
    const briefPath = getArg('--brief-path');
    if (!phase) {
      process.stderr.write('Usage: resolver.mjs --resolve-phase-model --phase <name> [--brief-path <path>] [--json]\n');
      process.exit(2);
    }
    const r = resolvePhaseModel(phase, briefPath || null, args, process.env);
    if (args.includes('--json')) {
      process.stdout.write(JSON.stringify(r) + '\n');
    } else {
      process.stdout.write(`model=${r.model} source=${r.source}\n`);
    }
    process.exit(0);
  }
  // Otherwise no-op (the module is primarily imported, not run directly).
}