#!/usr/bin/env node

import fs from 'node:fs/promises';
import { fileURLToPath } from 'node:url';

function hitId(hit) {
  return String(typeof hit === 'object' && hit !== null ? hit.fragmentId : hit);
}

function hitSource(hit) {
  return typeof hit === 'object' && hit !== null ? String(hit.sourceName || hit.title || '') : '';
}

export function reciprocalRank(retrieved, relevant) {
  const relevantSet = new Set(relevant.map(String));
  const rank = retrieved.findIndex((hit) => relevantSet.has(hitId(hit)));
  return rank < 0 ? 0 : 1 / (rank + 1);
}

export function recallAtK(retrieved, relevant) {
  const relevantSet = new Set(relevant.map(String));
  if (relevantSet.size === 0) return 0;
  const hits = retrieved.filter((hit) => relevantSet.has(hitId(hit)));
  return new Set(hits.map(hitId)).size / relevantSet.size;
}

export function ndcgAtK(retrieved, relevant) {
  const relevantSet = new Set(relevant.map(String));
  if (relevantSet.size === 0) return 0;
  const dcg = retrieved.reduce((sum, hit, index) =>
    sum + (relevantSet.has(hitId(hit)) ? 1 / Math.log2(index + 2) : 0), 0);
  const idealLength = Math.min(relevantSet.size, retrieved.length);
  const ideal = Array.from({ length: idealLength }, (_, index) => 1 / Math.log2(index + 2))
    .reduce((sum, value) => sum + value, 0);
  return ideal === 0 ? 0 : dcg / ideal;
}

export function evaluateCase(retrieved, testCase, k) {
  const ranked = retrieved.slice(0, k);
  const relevant = testCase.relevantFragmentIds || [];
  const forbiddenIds = new Set((testCase.forbiddenFragmentIds || []).map(String));
  const forbiddenSources = new Set((testCase.forbiddenSourceNames || []).map((value) => value.toLowerCase()));
  const requiredSources = new Set((testCase.requiredSourceNames || []).map((value) => value.toLowerCase()));
  const returnedSources = new Set(ranked.map(hitSource).filter(Boolean).map((value) => value.toLowerCase()));
  const forbiddenLeak = ranked.some((hit) => forbiddenIds.has(hitId(hit))
    || forbiddenSources.has(hitSource(hit).toLowerCase()));
  const missingRequiredSource = requiredSources.size > 0
    && ![...requiredSources].some((source) => returnedSources.has(source));
  const expectedNoEvidence = Boolean(testCase.expectedNoEvidence);
  return {
    id: testCase.id,
    caseType: testCase.caseType || (expectedNoEvidence ? 'no-answer' : 'answerable'),
    answerable: !expectedNoEvidence,
    recallAtK: expectedNoEvidence ? null : recallAtK(ranked, relevant),
    reciprocalRank: expectedNoEvidence ? null : reciprocalRank(ranked, relevant),
    ndcgAtK: expectedNoEvidence ? null : ndcgAtK(ranked, relevant),
    forbiddenLeak,
    wrongSource: forbiddenLeak || missingRequiredSource,
    returned: ranked.length,
    noEvidence: ranked.length === 0,
    noAnswerFalsePositive: expectedNoEvidence && ranked.length > 0
  };
}

function rate(rows, predicate) {
  return rows.length ? rows.filter(predicate).length / rows.length : 0;
}

function average(rows, key) {
  return rows.length ? rows.reduce((sum, row) => sum + row[key], 0) / rows.length : 0;
}

export function summarize(results) {
  const answerable = results.filter((row) => row.answerable);
  const noAnswer = results.filter((row) => !row.answerable);
  const byCaseType = Object.fromEntries([...new Set(results.map((row) => row.caseType))].sort().map((caseType) => {
    const rows = results.filter((row) => row.caseType === caseType);
    return [caseType, { cases: rows.length, forbiddenLeakageRate: rate(rows, (row) => row.forbiddenLeak) }];
  }));
  return {
    cases: results.length,
    answerableCases: answerable.length,
    noAnswerCases: noAnswer.length,
    recallAtK: average(answerable, 'recallAtK'),
    mrr: average(answerable, 'reciprocalRank'),
    ndcgAtK: average(answerable, 'ndcgAtK'),
    forbiddenLeakageRate: rate(results, (row) => row.forbiddenLeak),
    wrongSourceRate: rate(results, (row) => row.wrongSource),
    noAnswerFalsePositiveRate: rate(noAnswer, (row) => row.noAnswerFalsePositive),
    noAnswerPrecision: 1 - rate(noAnswer, (row) => row.noAnswerFalsePositive),
    byCaseType
  };
}

export function thresholdFailures(summary, thresholds) {
  const failures = [];
  if (thresholds.minRecall !== undefined && summary.recallAtK < thresholds.minRecall) {
    failures.push(`recallAtK ${summary.recallAtK} < ${thresholds.minRecall}`);
  }
  if (thresholds.minNdcg !== undefined && summary.ndcgAtK < thresholds.minNdcg) {
    failures.push(`ndcgAtK ${summary.ndcgAtK} < ${thresholds.minNdcg}`);
  }
  if (thresholds.minMrr !== undefined && summary.mrr < thresholds.minMrr) {
    failures.push(`mrr ${summary.mrr} < ${thresholds.minMrr}`);
  }
  if (thresholds.maxLeakage !== undefined && summary.forbiddenLeakageRate > thresholds.maxLeakage) {
    failures.push(`forbiddenLeakageRate ${summary.forbiddenLeakageRate} > ${thresholds.maxLeakage}`);
  }
  if (thresholds.maxNoAnswerFalsePositive !== undefined
      && summary.noAnswerFalsePositiveRate > thresholds.maxNoAnswerFalsePositive) {
    failures.push(`noAnswerFalsePositiveRate ${summary.noAnswerFalsePositiveRate} > ${thresholds.maxNoAnswerFalsePositive}`);
  }
  if (thresholds.maxWrongSource !== undefined && summary.wrongSourceRate > thresholds.maxWrongSource) {
    failures.push(`wrongSourceRate ${summary.wrongSourceRate} > ${thresholds.maxWrongSource}`);
  }
  return failures;
}

export function parseArgs(argv) {
  const options = { baseUrl: process.env.AIHR_EVAL_BASE_URL || 'http://127.0.0.1:8080', k: 5 };
  for (let index = 0; index < argv.length; index += 1) {
    const value = argv[index];
    if (value === '--dataset') options.dataset = argv[++index];
    else if (value === '--base-url') options.baseUrl = argv[++index];
    else if (value === '--token') options.token = argv[++index];
    else if (value === '--clientid') options.clientid = argv[++index];
    else if (value === '--k') options.k = Number(argv[++index]);
    else if (value === '--dry-run') options.dryRun = true;
    else if (value === '--min-recall') options.minRecall = Number(argv[++index]);
    else if (value === '--min-ndcg') options.minNdcg = Number(argv[++index]);
    else if (value === '--min-mrr') options.minMrr = Number(argv[++index]);
    else if (value === '--max-leakage') options.maxLeakage = Number(argv[++index]);
    else if (value === '--max-wrong-source') options.maxWrongSource = Number(argv[++index]);
    else if (value === '--max-no-answer-false-positive') options.maxNoAnswerFalsePositive = Number(argv[++index]);
    else throw new Error(`Unknown option: ${value}`);
  }
  if (!options.dataset) throw new Error('--dataset is required');
  if (!Number.isInteger(options.k) || options.k < 1 || options.k > 50) {
    throw new Error('--k must be an integer between 1 and 50');
  }
  for (const key of ['minRecall', 'minNdcg', 'minMrr', 'maxLeakage', 'maxWrongSource', 'maxNoAnswerFalsePositive']) {
    if (options[key] !== undefined && (!Number.isFinite(options[key]) || options[key] < 0 || options[key] > 1)) {
      throw new Error(`--${key.replace(/[A-Z]/g, (letter) => `-${letter.toLowerCase()}`)} must be between 0 and 1`);
    }
  }
  return options;
}

export function validateDataset(dataset) {
  if (dataset?.schemaVersion !== 1) throw new Error('dataset.schemaVersion must be 1');
  if (!dataset || !Array.isArray(dataset.cases) || dataset.cases.length === 0) {
    throw new Error('dataset.cases must be a non-empty array');
  }
  const ids = new Set();
  for (const item of dataset.cases) {
    if (!item.id || ids.has(item.id) || !item.query) throw new Error(`invalid or duplicate case: ${item.id || '<missing>'}`);
    ids.add(item.id);
    if (!item.expectedNoEvidence && (!Array.isArray(item.relevantFragmentIds) || item.relevantFragmentIds.length === 0)) {
      throw new Error(`answerable case must define relevantFragmentIds: ${item.id}`);
    }
    if (item.expectedNoEvidence && (item.relevantFragmentIds || []).length > 0) {
      throw new Error(`no-answer case cannot define relevantFragmentIds: ${item.id}`);
    }
  }
}

async function requestSearch(options, testCase, fetchImpl) {
  const headers = { 'content-type': 'application/json' };
  if (options.token) headers.Authorization = options.token.startsWith('Bearer ') ? options.token : `Bearer ${options.token}`;
  if (options.clientid) headers.clientid = options.clientid;
  const response = await fetchImpl(`${options.baseUrl.replace(/\/$/, '')}/api/knowledge/search`, {
    method: 'POST', headers,
    body: JSON.stringify({
      queryText: testCase.query,
      category: testCase.category || undefined,
      position: testCase.position || undefined,
      source: 'knowledge_search',
      limit: options.k
    })
  });
  const body = await response.json();
  if (!response.ok || body.code !== 200) {
    throw new Error(`case ${testCase.id} search failed with HTTP ${response.status} code ${body.code}`);
  }
  const snippets = body.data?.snippets || [];
  return snippets.filter((snippet) => snippet.fragmentId !== null && snippet.fragmentId !== undefined)
    .map((snippet) => ({ fragmentId: snippet.fragmentId, sourceName: snippet.title || '' }));
}

export async function run(options, dependencies = {}) {
  const dataset = JSON.parse(await fs.readFile(options.dataset, 'utf8'));
  validateDataset(dataset);
  if (options.dryRun) {
    return { datasetCode: dataset.datasetCode, schemaVersion: dataset.schemaVersion,
      cases: dataset.cases.length, k: options.k, dryRun: true };
  }
  const fetchImpl = dependencies.fetchImpl || globalThis.fetch;
  const results = [];
  for (const testCase of dataset.cases) {
    const retrieved = await requestSearch(options, testCase, fetchImpl);
    results.push(evaluateCase(retrieved, testCase, options.k));
  }
  const summary = summarize(results);
  const failures = thresholdFailures(summary, options);
  return { datasetCode: dataset.datasetCode, schemaVersion: dataset.schemaVersion, k: options.k,
    summary, thresholdPassed: failures.length === 0, thresholdFailures: failures, cases: results };
}

if (fileURLToPath(import.meta.url) === process.argv[1]) {
  run(parseArgs(process.argv.slice(2)))
    .then((result) => {
      console.log(JSON.stringify(result, null, 2));
      if (result.thresholdPassed === false) process.exitCode = 2;
    })
    .catch((error) => { console.error(error.message); process.exitCode = 1; });
}