#!/usr/bin/env node
/**
 * recommend.js — Select optimal provider using token budget intelligence
 *
 * Reads from the cached token-monitor run (if fresh) or probes directly.
 * Returns the best Teams provider considering 7d budget utilization.
 *
 * Selection rules (extra-usage credit era, post April 4 2026):
 *   0. Consult provider-check.json (pi session usability) — primary availability signal
 *      With extra-usage credit, 7d limits don't block sessions; broken OAuth tokens do.
 *   1. Among pi-usable providers: status must be "allowed" or "allowed_warning"
 *   2. Scan chain in order; take first with utilization_7d < SWITCH_THRESHOLD
 *   3. If none under threshold, take lowest-utilization allowed/allowed_warning provider
 *   4. If no usable Teams providers, return emergency=true (shelley-proxy)
 *
 * Note on provider-check.json:
 *   Written by ~/projects/provider-check/provider-check.ts (run by health-pulse hourly)
 *   at /tmp/provider-check.json. Stale if > 2 hours old — fallback to budget-only logic.
 *
 * Usage:
 *   node recommend.js                              # JSON output
 *   node recommend.js --threshold 0.80             # switch above 80% 7d
 *   node recommend.js --chain "vigilio,ludo,molto" # provider order
 *
 * Output JSON:
 *   { provider, model, reason, emergency, alternatives }
 */

import { getProviders } from './providers/index.js';
import { probeTeamsProvider } from './providers/anthropic-teams.js';
import { getCachedRun } from './logger.js';
import { readFileSync, existsSync, statSync } from 'fs';

const args = process.argv.slice(2);

// Parse --threshold
const threshIdx = args.indexOf('--threshold');
const SWITCH_THRESHOLD = threshIdx !== -1 ? parseFloat(args[threshIdx + 1]) : 0.75;

// Parse --chain
const chainIdx = args.indexOf('--chain');
const DEFAULT_CHAIN = ['team-vigilio', 'team-ludo', 'team-buio', 'team-molto', 'team-nadja'];
const PROVIDER_CHAIN = chainIdx !== -1
  ? args[chainIdx + 1].split(',').map(s => s.trim())
  : DEFAULT_CHAIN;

const DEFAULT_MODEL = 'claude-sonnet-4-6';
const EMERGENCY_FALLBACK = 'shelley-proxy';
const PROVIDER_CHECK_PATH = '/tmp/provider-check.json';
const PROVIDER_CHECK_MAX_AGE_MS = 2 * 60 * 60 * 1000; // 2 hours

// Load provider-check.json — returns Set of provider names that can start pi sessions
// Returns null if file missing, stale, or unreadable (fall through to budget-only logic)
function getPiUsableProviders() {
  try {
    if (!existsSync(PROVIDER_CHECK_PATH)) return null;
    const stat = statSync(PROVIDER_CHECK_PATH);
    const ageMs = Date.now() - stat.mtimeMs;
    if (ageMs > PROVIDER_CHECK_MAX_AGE_MS) return null; // stale — don't trust it
    const data = JSON.parse(readFileSync(PROVIDER_CHECK_PATH, 'utf8'));
    if (!data.results) return null;
    const usable = new Set(
      data.results
        .filter(r => r.status === 'ok')
        .map(r => r.provider)
    );
    return usable.size > 0 ? usable : null;
  } catch {
    return null;
  }
}

// Format utilization as percentage string
function pct(v) {
  if (v == null) return '?';
  return `${Math.round(v * 100)}%`;
}

async function getProviderData() {
  // Try fresh cache first (within 20 minutes from monitor.js runs)
  const cached = getCachedRun(20);
  if (cached && cached.providers) {
    // Cache hit — but check if all chain members are invalid_key
    // If so, probe fresh: invalid_key can be transient (API 401s during key rotation)
    // vs. rejected/exhausted which are stable budget states worth caching
    const chainProviders = PROVIDER_CHAIN
      .map(name => cached.providers[name])
      .filter(Boolean);
    const allInvalidOrMissing = chainProviders.length === 0 ||
      chainProviders.every(p => p.status === 'invalid_key' || p.status === 'error');
    if (!allInvalidOrMissing) {
      return { source: 'cache', providers: cached.providers };
    }
    // All invalid — fall through to fresh probe
  }

  // No cache — probe Teams providers directly (no full monitor run, targeted probes only)
  const allProviders = getProviders();
  const providers = {};

  for (const name of PROVIDER_CHAIN) {
    const p = allProviders[name];
    if (!p || p.type !== 'teams-direct') continue;
    try {
      const result = await probeTeamsProvider(p.name, p.baseUrl, p.apiKey);
      providers[name] = result;
    } catch (e) {
      providers[name] = { type: 'teams-direct', status: 'error', utilization_7d: null };
    }
  }

  return { source: 'fresh', providers };
}

async function main() {
  const { source, providers } = await getProviderData();

  // Filter to chain members that are Teams providers with data
  let candidates = PROVIDER_CHAIN
    .filter(name => providers[name] && providers[name].type === 'teams-direct')
    .map(name => ({ name, ...providers[name] }));

  // Apply pi-usability filter from provider-check.json
  // With extra-usage credit, 7d limits don't block sessions — OAuth token validity does.
  // provider-check.json tests actual pi session startup: the ground truth for usability.
  const piUsable = getPiUsableProviders();
  let piFilterApplied = false;
  if (piUsable) {
    const filtered = candidates.filter(p => piUsable.has(p.name));
    if (filtered.length > 0) {
      candidates = filtered;
      piFilterApplied = true;
    }
    // If no candidates pass pi check — don't filter (stale data or misconfigured check)
    // Fall through to budget-only selection so we don't always emergency-fallback
  }

  // Phase 1: first provider under threshold with status=allowed or allowed_warning
  // Both statuses can serve requests; allowed_warning just means approaching limit
  let best = null;
  for (const p of candidates) {
    if (p.status === 'allowed' || p.status === 'allowed_warning') {
      const util7d = p.utilization_7d ?? 0;
      if (util7d < SWITCH_THRESHOLD) {
        best = {
          name: p.name,
          reason: `7d at ${pct(util7d)}, 5h at ${pct(p.utilization_5h)} — under ${pct(SWITCH_THRESHOLD)} threshold (data: ${source}${piFilterApplied ? ', pi-check' : ''})`,
            piFilterApplied,
        };
        break;
      }
    }
  }

  // Phase 2: all over threshold — pick lowest 7d utilization (allowed or allowed_warning)
  // Prefer allowed over allowed_warning; both beat emergency fallback
  if (!best) {
    let lowestUtil = Infinity;
    let lowestCandidate = null;
    for (const p of candidates) {
      if (p.status === 'allowed' || p.status === 'allowed_warning') {
        const util7d = p.utilization_7d ?? 0;
        if (util7d < lowestUtil) {
          lowestUtil = util7d;
          lowestCandidate = p;
        }
      }
    }
    if (lowestCandidate) {
      const warningTag = lowestCandidate.status === 'allowed_warning' ? ', warning' : '';
      best = {
        name: lowestCandidate.name,
        reason: `all over threshold — best available at ${pct(lowestUtil)} 7d${warningTag} (data: ${source}${piFilterApplied ? ', pi-check' : ''})`,
        piFilterApplied,
      };
    }
  }

  // Build alternatives summary
  const alternatives = candidates
    .filter(p => !best || p.name !== best.name)
    .map(p => ({
      name: p.name,
      status: p.status,
      utilization_7d: p.utilization_7d,
      utilization_5h: p.utilization_5h,
    }));

  // Phase 3: no allowed Teams providers
  if (!best) {
    console.log(JSON.stringify({
      provider: EMERGENCY_FALLBACK,
      model: DEFAULT_MODEL,
      reason: 'all Teams providers exhausted — emergency fallback',
      emergency: true,
      alternatives,
    }, null, 2));
    return;
  }

  console.log(JSON.stringify({
    provider: best.name,
    model: DEFAULT_MODEL,
    reason: best.reason,
    emergency: false,
    alternatives,
  }, null, 2));
}

main().catch(e => {
  // Safe fallback — never crash beat.sh
  console.log(JSON.stringify({
    provider: 'team-vigilio',
    model: DEFAULT_MODEL,
    reason: `recommend.js error — defaulting: ${e.message}`,
    emergency: false,
    alternatives: [],
  }, null, 2));
  process.exit(0);
});