// src/pipeline/batch.mjs
import fs from 'fs/promises';
import path from 'path';

import { preview } from './util.mjs';
import crypto from 'crypto';
import {
  DEFAULT_SEEDS_PATH,
  DEFAULT_OUT_PATH,
  loadSeedQuestions,
  seedToQuestion,
} from './seeds.mjs';
import { runPipelineStep } from './step.mjs';
import { loadProviderFor } from '../providers/provider.mjs';
import { runQuestionGenerator } from '../question/question_core.mjs';
import { fetchChunksFromIndex } from '../retrieval/retrieval.mjs';
import { loadRagChunks } from '../retrieval/jsonl_chunks.mjs';
import {
  chunkIdFromContent,
  questionId,
} from './cache.mjs';
import {
  getCachedQuestions,
  saveQuestions,
  getCachedGeneration,
  saveGeneration,
  getCachedReward,
  saveReward,
  saveVerification,
} from './cache.mjs';

/**
 * Append a single accepted record to a JSONL file.
 */
export async function appendGoldRecord(outPath, record) {
  const line = JSON.stringify(record) + '\n';
  await fs.mkdir(path.dirname(outPath), { recursive: true });
  await fs.appendFile(outPath, line, 'utf8');
}

/**
 * Run the pipeline over a batch of seeds and write accepted
 * samples to a JSONL file.
 *
 * Modes:
 *   - question-first (default): seeds are CHUNKS; we generate questions from each chunk
 *   - static:                  seeds are questions (legacy / low-priority mode)
 *
 * Options:
 *   - seedsPath: JSONL of seeds (defaults to test_samples/seed_questions.jsonl)
 *   - outPath:   output JSONL (defaults to gold/pipeline_gold.jsonl)
 *   - limit:     max number of seeds to process
 *   - verbose:   extra per-stage logging
 *   - logger:    optional logger (defaults to console)
 *   - seedMode:  'question-first' | 'static' (overrides env + default)
 *
 * Returns:
 *   {
 *     mode,
 *     total,
 *     processed,          // number of questions run through pipeline
 *     accepted,
 *     outPath,
 *     statusCounts,
 *     processedSeeds?,    // (question-first) how many chunks actually used
 *     processedQuestions? // (question-first) alias for processed
 *   }
 */
export async function runPipelineBatch({
  seedsPath = DEFAULT_SEEDS_PATH,
  outPath = DEFAULT_OUT_PATH,
  limit,
  chunkLimit,
  verbose = false,
  logger = console,
  seedMode = process.env.PIPELINE_SEED_MODE || 'question-first',
  onProgress = () => {},
} = {}) {
  const log = logger?.log?.bind(logger) || console.log;
  const errLog = logger?.error?.bind(logger) || console.error;

  if (verbose) {
    log('[pipeline] mode:', seedMode);
    log('[pipeline] outPath:', outPath);
  }

  let processed = 0; // number of questions sent through runPipelineStep
  let accepted = 0;
  const statusCounts = {};

  // ----------------------------------------
  // MODE 1: static questions from JSONL (legacy / tests)
  // ----------------------------------------
  if (seedMode === 'static') {
    const seeds = await loadSeedQuestions(seedsPath);
    const maxSeeds = typeof limit === 'number' ? limit : seeds.length;

    if (verbose) {
      log('[pipeline] seedsPath (static questions):', seedsPath);
    }

    for (let idx = 0; idx < maxSeeds; idx++) {
      const seed = seeds[idx];
      const question = seedToQuestion(seed);
      const label = `[${idx + 1}/${maxSeeds}]`;

      log(`→ ${label} Running pipeline for: "${question}"`);

      const tStart = Date.now();
      try {
        const result = await runPipelineStep({
          question,
          verbose,
          logger,
        });

        processed += 1;
        statusCounts[result.status] =
          (statusCounts[result.status] || 0) + 1;

        onProgress({
          processed,
          accepted,
          status: result.status,
          elapsedMs: Date.now() - tStart,
          question,
          mode: seedMode,
        });

        if (verbose) {
          log(`   ↳ status: ${result.status}`);
        }

        if (result.status === 'accepted') {
          const record = {
            question,
            context: result.context,
            sample: {
              answer: result.gen?.answer,
              thought: result.gen?.thought,
              raw: result.gen?.raw,
              confidence: result.gen?.confidence,
              evidence: result.gen?.evidence,
              limitations: result.gen?.limitations,
              thinking: result.gen?.thinking,
            },
            verifier: result.ver,
            reward: result.rew,
          };

          await appendGoldRecord(outPath, record);
          accepted += 1;
        }
      } catch (e) {
        const msg = e?.message || String(e);
        processed += 1;
        statusCounts.pipeline_error =
          (statusCounts.pipeline_error || 0) + 1;
        onProgress({
          processed,
          accepted,
          status: 'pipeline_error',
          elapsedMs: Date.now() - tStart,
          question,
          mode: seedMode,
        });
        errLog('   [pipeline] ERROR:', msg);
      }
    }

    return {
      mode: seedMode,
      total: seeds.length,
      processed,
      accepted,
      outPath,
      statusCounts,
    };
  }

  // ----------------------------------------
  // MODE 2: question-first (JSONL or ES chunks → QG → pipeline)
  // ----------------------------------------
  if (seedMode === 'question-first') {
    const questionProvider = loadProviderFor('question');
    const generatorProviderName =
      process.env.GENERATOR_PROVIDER || 'ollama';
    const verifierProviderName =
      process.env.VERIFIER_PROVIDER || generatorProviderName;
    const rewardProviderName =
      process.env.REWARD_PROVIDER || generatorProviderName;

    const maxQuestionsPerChunk = Number(
      process.env.QUESTION_MAX_PER_CHUNK ||
        process.env.QUESTION_MAX ||
        '5',
    );

    const questionCap =
      typeof limit === 'number' ? limit : Number.POSITIVE_INFINITY;

    const effectiveChunkLimit = (() => {
      if (typeof chunkLimit === 'number') return chunkLimit;
      const envLimit =
        process.env.PIPELINE_CHUNK_LIMIT ||
        process.env.PIPELINE_CHUNKS ||
        process.env.PIPELINE_CHUNK_SAMPLE;
      const parsed = envLimit != null ? Number(envLimit) : NaN;
      return Number.isFinite(parsed) ? parsed : undefined;
    })();

    // Decide where chunks come from:
    //   PIPELINE_CHUNK_SOURCE = 'jsonl' | 'es'
    const chunkSource =
      process.env.PIPELINE_CHUNK_SOURCE || 'jsonl';

    if (verbose) {
      if (chunkSource === 'jsonl') {
        const p =
          process.env.RAG_CHUNKS_PATH ||
          'data/rag_chunks.jsonl';
        log(
          `[pipeline] loading chunks from JSONL (${p}), limit=${effectiveChunkLimit ?? 'all'}`,
        );
      } else {
        log(
          `[pipeline] fetching chunks from ES (limit=${effectiveChunkLimit ?? 'all'})`,
        );
      }
    }

    let chunks = [];
    try {
      if (chunkSource === 'jsonl') {
        chunks = await loadRagChunks(effectiveChunkLimit);
      } else {
        chunks = await fetchChunksFromIndex(effectiveChunkLimit);
      }
    } catch (e) {
      const msg = e?.message || String(e);
      errLog('[pipeline] ERROR loading chunks:', msg);
      return {
        mode: seedMode,
        total: 0,
        processed: 0,
        accepted: 0,
        outPath,
        statusCounts: { chunk_load_error: 1 },
      };
    }

    const totalChunks = chunks.length;
    let processedSeeds = 0;

    // Optional random walk over chunks
    const randomWalk = (() => {
      const v =
        process.env.PIPELINE_RANDOM_WALK ||
        process.env.PIPELINE_CHUNK_ORDER;
      if (!v) return false;
      const s = String(v).toLowerCase();
      return s === '1' || s === 'true' || s === 'yes' || s === 'random';
    })();

    if (randomWalk && chunks.length > 1) {
      for (let i = chunks.length - 1; i > 0; i--) {
        const j = crypto.randomInt(i + 1);
        [chunks[i], chunks[j]] = [chunks[j], chunks[i]];
      }
    }

    for (let idx = 0; idx < chunks.length; idx++) {
      if (processed >= questionCap) break;

      const chunk = chunks[idx];
      const label = `[chunk ${idx + 1}/${chunks.length}]`;
      const contextText = chunk.content;

      const stableChunkId =
        chunk.id ||
        chunkIdFromContent(
          contextText,
          chunk.sourceId || chunk.source?.id,
        );
      chunk.id = stableChunkId;

      if (!contextText || !contextText.trim()) {
        if (verbose) {
          log(`${label} chunk content empty, skipping`);
        }
        continue;
      }

      processedSeeds += 1;

      if (verbose) {
        log(`\n🧩 ${label} generating questions from chunk…`);
        log(`   [question] chunk id: ${chunk.id}`);
        log(
          '   [question] chunk preview:\n   ' +
            preview(contextText, 300).replace(/\n/g, '\n   '),
        );
        log(
          `   [question] using provider="question" maxQuestions=${maxQuestionsPerChunk}`,
        );
      }

      // 1) generate questions from this chunk (or load cache)
      let qResult;
      let questions = [];
      try {
        const cachedQRecords = await getCachedQuestions(stableChunkId);
        if (cachedQRecords.length > 0) {
          questions = cachedQRecords[0].questions.slice(
            0,
            maxQuestionsPerChunk,
          );
          if (verbose)
            log(
              `   [question] loaded ${questions.length} cached question(s)`,
            );
        } else {
          qResult = await runQuestionGenerator(
            contextText,
            questionProvider,
            { maxQuestions: maxQuestionsPerChunk },
          );
          questions = qResult?.questions || [];
          if (questions.length > 0) {
            await saveQuestions(stableChunkId, questions, {
              provider: process.env.QUESTION_PROVIDER,
              model: process.env.QUESTION_MODEL,
            });
          }
        }
      } catch (e) {
        const msg = e?.message || String(e);
        statusCounts.question_error =
          (statusCounts.question_error || 0) + 1;
        if (verbose) {
          errLog('   [question] ERROR:', msg);
        }
        continue;
      }

      if (verbose) {
        log(
          `   [question] generated ${questions.length} question(s) from this chunk`,
        );
        if (questions.length > 0) {
          log(
            '   [question] first question: "' +
              preview(questions[0], 200) +
              '"',
          );
        }
      }

      // 2) run full pipeline for each generated question
      for (const q of questions) {
        if (processed >= questionCap) break;
        if (!q || !q.trim()) continue;

        const qId = questionId(stableChunkId, q);
        const cachedReward = await getCachedReward(stableChunkId, qId);
        if (cachedReward?.ok) {
          processed += 1;
          accepted += 1;
          statusCounts.cached_reward =
            (statusCounts.cached_reward || 0) + 1;
          onProgress({
            processed,
            accepted,
            status: 'cached_reward',
            elapsedMs: 0,
            question: q,
            mode: seedMode,
          });
          if (verbose)
            log(
              `   → [q ${processed}] using cached reward, skipping stages`,
            );
          continue;
        }

        const cachedGen = await getCachedGeneration(stableChunkId, qId);

        const qLabel = `[q ${processed + 1}]`;
        log(
          `   → ${qLabel} Running pipeline for generated question: "${q}"`,
        );

        const tStart = Date.now();
        try {
          const result = await runPipelineStep({
            question: q,
            initialContext: [chunk], // IMPORTANT: reuse SAME chunk, no second retrieval
            cachedGen,
            verbose,
            logger,
          });

          processed += 1;
          statusCounts[result.status] =
            (statusCounts[result.status] || 0) + 1;

          onProgress({
            processed,
            accepted,
            status: result.status,
            elapsedMs: Date.now() - tStart,
            question: q,
            mode: seedMode,
          });

          if (verbose) {
            log(`     ↳ status: ${result.status}`);
          }

          let savedGenRecord = null;
          if (result.gen) {
            savedGenRecord = await saveGeneration(stableChunkId, qId, result.gen, {
              provider: generatorProviderName,
              model: process.env.GENERATOR_MODEL,
            });
            // keep gen_id on the in-memory object for downstream linking
            if (savedGenRecord?.gen_id) {
              result.gen.gen_id = savedGenRecord.gen_id;
            }
          }
          const genIdForFollowups =
            savedGenRecord?.gen_id || cachedGen?.gen_id;
          if (result.ver) {
            await saveVerification(
              stableChunkId,
              qId,
              genIdForFollowups,
              result.ver,
              {
                provider: verifierProviderName,
                model: process.env.VERIFIER_MODEL,
              },
            );
          }
          if (result.rew) {
            await saveReward(
              stableChunkId,
              qId,
              genIdForFollowups,
              result.rew,
              { provider: rewardProviderName, model: process.env.REWARD_MODEL },
            );
          }

          if (result.status === 'accepted') {
            const record = {
              question: q,
              sourceChunkId: chunk.id,
              sourceChunk: contextText,
              sourceDoc: chunk.source,
              context: result.context,
              sample: {
                answer: result.gen?.answer,
                thought: result.gen?.thought,
                raw: result.gen?.raw,
              },
              verifier: result.ver,
              reward: result.rew,
            };

            await appendGoldRecord(outPath, record);
            accepted += 1;

            if (verbose) {
              log('     ✓ accepted and written to gold JSONL');
            }
          }
        } catch (e) {
          const msg = e?.message || String(e);
          processed += 1;
          statusCounts.pipeline_error =
            (statusCounts.pipeline_error || 0) + 1;
          onProgress({
            processed,
            accepted,
            status: 'pipeline_error',
            elapsedMs: Date.now() - tStart,
            question: q,
            mode: seedMode,
          });
          errLog('     [pipeline] ERROR:', msg);
        }
      }
    }

    return {
      mode: seedMode,
      total: totalChunks,
      processed, // number of questions processed
      processedSeeds,
      processedQuestions: processed,
      accepted,
      outPath,
      statusCounts,
    };
  }

  throw new Error(`Unknown PIPELINE_SEED_MODE: ${seedMode}`);
}