/**
 * Validation logic using LLM service
 */

import { readFileSync, readdirSync, writeFileSync, existsSync } from 'fs';
import { join } from 'path';
import type { LLMCorrectionResult } from '@/client/typescript/dist/api.js';
import type {
  ValidationCache,
  FieldValidationResult,
  FileValidationResult,
  ValidationOptions,
  ValidationStats,
} from './types.js';
import { hashContent, getCacheKey, saveCache } from './cache-manager.js';
import { extractStrings, setNestedValue } from './file-utils.js';

export async function validateFieldWithLLM(
  correctWithLLM: (text: string, options: { useReasoning: boolean }) => Promise<LLMCorrectionResult>,
  file: string,
  fieldPath: string,
  value: string,
  cache: ValidationCache,
  useReasoning: boolean,
  verbose: boolean
): Promise<{ result: FieldValidationResult; cached: boolean }> {
  const cacheKey = getCacheKey(file, fieldPath);
  const contentHash = hashContent(value);

  // Check cache
  const cached = cache.entries[cacheKey];
  if (cached && cached.contentHash === contentHash) {
    return {
      result: {
        field: fieldPath,
        originalValue: value,
        changes: cached.changes,
        confidence: cached.confidence,
      },
      cached: true,
    };
  }

  try {
    const result: LLMCorrectionResult = await correctWithLLM(value, {
      useReasoning,
    });

    // Update cache
    cache.entries[cacheKey] = {
      contentHash,
      validatedAt: new Date().toISOString(),
      isValid: result.changes.length === 0,
      changes: result.changes,
      confidence: result.confidence,
    };

    return {
      result: {
        field: fieldPath,
        originalValue: value,
        correctedValue: result.corrected !== value ? result.corrected : undefined,
        changes: result.changes,
        confidence: result.confidence,
      },
      cached: false,
    };
  } catch (error) {
    if (verbose) {
      console.error(`    ✗ [${fieldPath}] LLM error:`, error);
    }
    return {
      result: {
        field: fieldPath,
        originalValue: value,
        changes: [],
        confidence: 0,
      },
      cached: false,
    };
  }
}

export async function validateFile(
  correctWithLLM: (text: string, options: { useReasoning: boolean }) => Promise<LLMCorrectionResult>,
  file: string,
  content: Record<string, unknown>,
  cache: ValidationCache,
  useReasoning: boolean,
  verbose: boolean
): Promise<{ result: FileValidationResult; cacheHits: number; cacheMisses: number }> {
  const strings = extractStrings(content);
  const fieldResults: FieldValidationResult[] = [];
  let cacheHits = 0;
  let cacheMisses = 0;

  for (const { path, value } of strings) {
    const { result, cached } = await validateFieldWithLLM(
      correctWithLLM,
      file,
      path,
      value,
      cache,
      useReasoning,
      verbose
    );
    if (cached) {
      cacheHits++;
    } else {
      cacheMisses++;
    }
    if (result.changes.length > 0) {
      fieldResults.push(result);
    }
  }

  return {
    result: {
      isValid: fieldResults.length === 0,
      fieldResults,
      totalChanges: fieldResults.reduce((sum, r) => sum + r.changes.length, 0),
    },
    cacheHits,
    cacheMisses,
  };
}

export function applyCorrections(
  content: Record<string, unknown>,
  result: FileValidationResult
): Record<string, unknown> {
  const corrected = JSON.parse(JSON.stringify(content));

  for (const fieldResult of result.fieldResults) {
    if (fieldResult.correctedValue) {
      setNestedValue(corrected, fieldResult.field, fieldResult.correctedValue);
    }
  }

  return corrected;
}

export async function runValidation(
  correctWithLLM: (text: string, options: { useReasoning: boolean }) => Promise<LLMCorrectionResult>,
  localesDir: string,
  cacheFile: string,
  targetFiles: string[] | null,
  options: ValidationOptions,
  cache: ValidationCache
): Promise<ValidationStats> {
  const files = targetFiles && targetFiles.length > 0
    ? targetFiles.filter((f) => existsSync(join(localesDir, f)))
    : readdirSync(localesDir).filter((f) => f.endsWith('.json'));

  if (files.length === 0) {
    console.log('No locale files to validate\n');
    return { totalChanges: 0, filesModified: 0, filesScanned: 0, cacheHits: 0, cacheMisses: 0 };
  }

  console.log(`Found ${files.length} locale file(s) to validate\n`);

  let totalChanges = 0;
  let filesModified = 0;
  let totalCacheHits = 0;
  let totalCacheMisses = 0;

  for (const file of files) {
    const filePath = join(localesDir, file);
    const content = JSON.parse(readFileSync(filePath, 'utf-8')) as Record<string, unknown>;
    const strings = extractStrings(content);

    const { result, cacheHits, cacheMisses } = await validateFile(
      correctWithLLM,
      file,
      content,
      cache,
      options.reasoning,
      options.verbose
    );
    totalCacheHits += cacheHits;
    totalCacheMisses += cacheMisses;

    const cacheInfo = cacheHits > 0 ? ` [${cacheHits} cached, ${cacheMisses} new]` : '';
    console.log(`📄 ${file} (${strings.length} strings)${cacheInfo}`);

    if (result.totalChanges > 0) {
      console.log(`  ⚠ Found ${result.totalChanges} suggested change(s):\n`);

      for (const fieldResult of result.fieldResults) {
        console.log(`  [${fieldResult.field}] (confidence: ${(fieldResult.confidence * 100).toFixed(0)}%)`);

        for (const change of fieldResult.changes) {
          console.log(`    ${change.type}: "${change.original}" → "${change.replacement}"`);
          console.log(`           Reason: ${change.reason}`);
        }
        console.log('');
      }

      totalChanges += result.totalChanges;

      if (options.fix && result.fieldResults.some((r) => r.correctedValue)) {
        const corrected = applyCorrections(content, result);

        if (!options.dryRun) {
          writeFileSync(filePath, JSON.stringify(corrected, null, 2) + '\n');
          console.log(`  ✓ Applied corrections\n`);
          filesModified++;
        } else {
          console.log(`  → Would apply corrections (dry-run)\n`);
        }
      }
    } else if (options.verbose) {
      console.log(`  ✓ No issues found\n`);
    }

    // Save cache periodically (every file)
    saveCache(cacheFile, cache, options.noCache);
  }

  return {
    totalChanges,
    filesModified,
    filesScanned: files.length,
    cacheHits: totalCacheHits,
    cacheMisses: totalCacheMisses,
  };
}