#!/usr/bin/env node
/**
 * Splits slash-separated alternatives in lesson corePatterns into separate entries.
 *
 * Default mode is dry-run (no writes).
 * Use --apply to persist changes.
 *
 * Optional filters:
 *   --course-id=<id>
 *   --lesson-id=<id>
 */

import { Op } from 'sequelize';
import { sequelize } from '../utils/sequelize.js';
import VocabCourseLesson from '../models/community/vocab_course_lesson.js';

function parseArgs(argv) {
  const args = {
    apply: false,
    courseId: null,
    lessonId: null,
  };

  argv.forEach((arg) => {
    if (arg === '--apply') {
      args.apply = true;
      return;
    }
    if (arg.startsWith('--course-id=')) {
      const value = Number(arg.split('=')[1]);
      if (Number.isFinite(value) && value > 0) {
        args.courseId = value;
      }
      return;
    }
    if (arg.startsWith('--lesson-id=')) {
      const value = Number(arg.split('=')[1]);
      if (Number.isFinite(value) && value > 0) {
        args.lessonId = value;
      }
    }
  });

  return args;
}

function normalizeText(value) {
  return String(value || '').trim().replace(/\s+/g, ' ');
}

function splitAlternatives(value) {
  const text = normalizeText(value);
  if (!text) return [];
  const parts = text
    .split(/\s+\/\s+/)
    .map((part) => normalizeText(part))
    .filter(Boolean);
  return parts.length >= 2 ? parts : [text];
}

function normalizePatternEntry(entry) {
  if (!entry || typeof entry !== 'object') return null;
  const target = normalizeText(entry.target || '');
  const gloss = normalizeText(entry.gloss || '');
  if (!target || !gloss) return null;
  return { target, gloss };
}

function expandPatternAlternatives(entry) {
  const normalized = normalizePatternEntry(entry);
  if (!normalized) return { expanded: [], changed: false, skipped: false };

  const targets = splitAlternatives(normalized.target);
  const glosses = splitAlternatives(normalized.gloss);

  const hasTargetAlternatives = targets.length > 1;
  const hasGlossAlternatives = glosses.length > 1;

  if (!hasTargetAlternatives && !hasGlossAlternatives) {
    return { expanded: [normalized], changed: false, skipped: false };
  }

  if (hasTargetAlternatives && !hasGlossAlternatives) {
    return {
      expanded: targets.map((target) => ({ target, gloss: normalized.gloss })),
      changed: true,
      skipped: false,
    };
  }

  if (!hasTargetAlternatives && hasGlossAlternatives) {
    return {
      expanded: glosses.map((gloss) => ({ target: normalized.target, gloss })),
      changed: true,
      skipped: false,
    };
  }

  if (targets.length === glosses.length) {
    return {
      expanded: targets.map((target, index) => ({ target, gloss: glosses[index] })),
      changed: true,
      skipped: false,
    };
  }

  return { expanded: [normalized], changed: false, skipped: true };
}

function dedupePatterns(patterns) {
  const out = [];
  const seen = new Set();
  patterns.forEach((entry) => {
    const normalized = normalizePatternEntry(entry);
    if (!normalized) return;
    const key = `${normalized.target.toLowerCase()}|${normalized.gloss.toLowerCase()}`;
    if (seen.has(key)) return;
    seen.add(key);
    out.push(normalized);
  });
  return out;
}

async function main() {
  const args = parseArgs(process.argv.slice(2));

  const where = {};
  if (args.courseId) where.courseId = args.courseId;
  if (args.lessonId) where.id = args.lessonId;

  const lessons = await VocabCourseLesson.findAll({
    where: Object.keys(where).length ? where : undefined,
    attributes: ['id', 'courseId', 'lessonNumber', 'title', 'corePatterns'],
    order: [['courseId', 'ASC'], ['lessonNumber', 'ASC']],
  });

  let affectedLessons = 0;
  let changedPatterns = 0;
  let skippedComplexPatterns = 0;

  console.log(`Gefundene Lektionen: ${lessons.length}`);
  console.log(`Modus: ${args.apply ? 'APPLY (schreibt Änderungen)' : 'DRY-RUN (keine Änderungen)'}`);

  for (const lesson of lessons) {
    const current = Array.isArray(lesson.corePatterns) ? lesson.corePatterns : [];
    if (current.length === 0) continue;

    let lessonChanged = false;
    let lessonChangedCount = 0;
    let lessonSkippedCount = 0;

    const expanded = [];
    current.forEach((entry) => {
      const { expanded: splitEntries, changed, skipped } = expandPatternAlternatives(entry);
      if (changed) {
        lessonChanged = true;
        lessonChangedCount += 1;
      }
      if (skipped) {
        lessonSkippedCount += 1;
      }
      expanded.push(...splitEntries);
    });

    const deduped = dedupePatterns(expanded);
    const oldSerialized = JSON.stringify(dedupePatterns(current));
    const newSerialized = JSON.stringify(deduped);

    if (oldSerialized === newSerialized) {
      skippedComplexPatterns += lessonSkippedCount;
      continue;
    }

    affectedLessons += 1;
    changedPatterns += lessonChangedCount;
    skippedComplexPatterns += lessonSkippedCount;

    console.log(
      `- Kurs ${lesson.courseId}, Lektion #${lesson.lessonNumber} (${lesson.id}) "${lesson.title}": `
      + `${current.length} -> ${deduped.length} Core-Patterns`
      + (lessonSkippedCount > 0 ? `, übersprungen (uneindeutig): ${lessonSkippedCount}` : '')
    );

    if (args.apply) {
      await lesson.update({ corePatterns: deduped });
    }
  }

  console.log('');
  console.log(`Betroffene Lektionen: ${affectedLessons}`);
  console.log(`Geänderte Pattern-Einträge (vor Dedupe): ${changedPatterns}`);
  console.log(`Uneindeutige Slash-Fälle (nicht automatisch geändert): ${skippedComplexPatterns}`);
}

main()
  .then(async () => {
    await sequelize.close();
  })
  .catch(async (error) => {
    console.error('Fehler beim Normalisieren der Core-Patterns:', error);
    await sequelize.close();
    process.exit(1);
  });