import fs from 'node:fs/promises';
import os from 'node:os';
import path from 'node:path';
import { afterEach, beforeEach, describe, expect, it } from 'vitest';
import { mergeConfigs } from '../../../src/config/configLoad.js';
import type { RepomixConfigFile, RepomixConfigMerged, RepomixOutputStyle } from '../../../src/config/configSchema.js';
import { collectFiles } from '../../../src/core/file/fileCollect.js';
import { resolveFileLevel } from '../../../src/core/file/fileLevelResolve.js';
import { readRawFile } from '../../../src/core/file/fileRead.js';
import { searchFiles } from '../../../src/core/file/fileSearch.js';
import type { ProcessedFile } from '../../../src/core/file/fileTypes.js';
import fileProcessWorker from '../../../src/core/file/workers/fileProcessWorker.js';
import { produceOutput } from '../../../src/core/packager/produceOutput.js';
import { pack } from '../../../src/core/packager.js';
import { filterOutUntrustedFiles } from '../../../src/core/security/filterOutUntrustedFiles.js';
import { validateFileSafety } from '../../../src/core/security/validateFileSafety.js';

// Behavior-level regression tests for multi-root packing.
//
// PR #1562 (token-count cache) initially merged FileMetrics results by file
// path via a Map, which silently collapsed entries when the same relative path
// appeared under multiple roots (e.g. `packages/a/README.md` and
// `packages/b/README.md` both relativize to `README.md`). That bug was fixed
// at the metrics layer with index-based assembly. The metrics layer is mocked
// out below, so this spec does NOT re-catch the metrics-layer flavor — that
// is owned by calculateFileMetrics.test.ts.
//
// What this spec catches instead is a content-side collapse in any layer that
// operates on the *flattened* (multi-root) file list — `processFiles`,
// `produceOutput`, or any intermediate assembly between them. A Map<path, ...>
// dedup at that level would drop one root's bytes from the file we hand to
// the LLM. The unique content sentinels per root make that visible.
//
// Out of scope:
// - `collectFiles` itself is called once per root, so a per-call internal
//   dedup-by-path would not collapse cross-root copies and would not be
//   detected here.
// - A collapse in the file-tree generator alone would still let both root
//   bodies reach the files section — see tests around
//   `generateTreeStringWithRoots` for tree-only guarantees.

const buildMergedConfig = (
  cwd: string,
  outputFilePath: string,
  style: RepomixOutputStyle,
  overrides: Partial<RepomixConfigFile> = {},
): RepomixConfigMerged =>
  mergeConfigs(cwd, overrides, {
    output: {
      filePath: outputFilePath,
      style,
      git: { sortByChanges: false, includeDiffs: false, includeLogs: false },
    },
  });

const runPack = (rootDirs: string[], config: RepomixConfigMerged) =>
  pack(rootDirs, config, () => {}, {
    searchFiles,
    sortPaths: (filePaths) => filePaths,
    collectFiles: (filePaths, root, cfg, progressCallback) =>
      collectFiles(filePaths, root, cfg, progressCallback, { readRawFile }),
    processFiles: async (rawFiles, cfg) => {
      const processedFiles: ProcessedFile[] = [];
      for (const rawFile of rawFiles) {
        const level = resolveFileLevel(rawFile.path, cfg.output);
        processedFiles.push(await fileProcessWorker({ rawFile, config: cfg, level }));
      }
      return processedFiles;
    },
    // No secrets in these fixtures — short-circuit the security scan to keep
    // the test fast and focused on the multi-root assembly path.
    validateFileSafety: (rawFiles, progressCallback, cfg, gitDiff, gitLog) =>
      validateFileSafety(rawFiles, progressCallback, cfg, gitDiff, gitLog, {
        runSecurityCheck: async () => [],
        filterOutUntrustedFiles,
      }),
    produceOutput,
    createMetricsTaskRunner: () => ({
      taskRunner: { run: async () => 0, cleanup: async () => {} },
      warmupPromise: Promise.resolve(),
    }),
    calculateMetrics: async (processedFiles) => ({
      totalFiles: processedFiles.length,
      totalCharacters: processedFiles.reduce((acc, f) => acc + f.content.length, 0),
      totalTokens: 0,
      gitDiffTokenCount: 0,
      gitLogTokenCount: 0,
      fileCharCounts: Object.fromEntries(processedFiles.map((f) => [f.path, f.content.length])),
      fileTokenCounts: Object.fromEntries(processedFiles.map((f) => [f.path, 0])),
      suspiciousFilesResults: [],
      suspiciousGitDiffResults: [],
    }),
  });

const countOccurrences = (haystack: string, needle: string): number => {
  let count = 0;
  let index = haystack.indexOf(needle);
  while (index !== -1) {
    count++;
    index = haystack.indexOf(needle, index + needle.length);
  }
  return count;
};

const toDisplayPath = (filePath: string): string => filePath.replaceAll(path.win32.sep, path.posix.sep);

describe('multi-root pack spec', () => {
  let rootAParent: string;
  let rootBParent: string;
  let rootA: string;
  let rootB: string;
  let outputDir: string;
  let outputPath: string;

  beforeEach(async () => {
    rootAParent = await fs.mkdtemp(path.join(os.tmpdir(), 'repomix-multiroot-parent-a-'));
    rootBParent = await fs.mkdtemp(path.join(os.tmpdir(), 'repomix-multiroot-parent-b-'));
    rootA = path.join(rootAParent, 'app');
    rootB = path.join(rootBParent, 'app');
    outputDir = await fs.mkdtemp(path.join(os.tmpdir(), 'repomix-multiroot-out-'));
    outputPath = path.join(outputDir, 'output.xml');

    // Same root basename and same relative paths, but unique content so a
    // collapsing implementation produces an obviously-wrong output.
    await fs.mkdir(rootA);
    await fs.writeFile(path.join(rootA, 'README.md'), '# Root A\nMARKER_FROM_ROOT_A\n');
    await fs.mkdir(path.join(rootA, 'src'));
    await fs.writeFile(path.join(rootA, 'src', 'index.ts'), 'export const fromA = "ROOT_A_SRC_MARKER";\n');

    await fs.mkdir(rootB);
    await fs.writeFile(path.join(rootB, 'README.md'), '# Root B (totally different)\nMARKER_FROM_ROOT_B\n');
    await fs.mkdir(path.join(rootB, 'src'));
    await fs.writeFile(path.join(rootB, 'src', 'index.ts'), 'export const fromB = "ROOT_B_SRC_MARKER";\n');
  });

  afterEach(async () => {
    await fs.rm(rootAParent, { recursive: true, force: true });
    await fs.rm(rootBParent, { recursive: true, force: true });
    await fs.rm(outputDir, { recursive: true, force: true });
  });

  it('preserves both unique contents of a duplicate relative path when packing multiple roots (xml)', async () => {
    const config = buildMergedConfig(outputDir, outputPath, 'xml');
    await runPack([rootA, rootB], config);

    const output = await fs.readFile(outputPath, 'utf-8');
    // The contract: each root's bytes survive into the pack. A
    // Map<path, FileMetrics> collapse — the one PR #1562 fixed in the metrics
    // layer — would drop one of these markers entirely.
    expect(output).toContain('MARKER_FROM_ROOT_A');
    expect(output).toContain('MARKER_FROM_ROOT_B');
    expect(output).toContain('ROOT_A_SRC_MARKER');
    expect(output).toContain('ROOT_B_SRC_MARKER');
  });

  it('preserves both unique contents in plain style too', async () => {
    // Plain style takes a different rendering path; the assertion is
    // style-agnostic because the collapse, if reintroduced, would surface
    // identically in both.
    const config = buildMergedConfig(outputDir, outputPath, 'plain');
    await runPack([rootA, rootB], config);

    const output = await fs.readFile(outputPath, 'utf-8');
    expect(output).toContain('MARKER_FROM_ROOT_A');
    expect(output).toContain('MARKER_FROM_ROOT_B');
  });

  it.each([
    'xml',
    'markdown',
    'plain',
  ] as const)('packs each duplicate-relative-path multi-root file exactly once in %s style', async (style) => {
    const config = buildMergedConfig(outputDir, outputPath, style);
    await runPack([rootA, rootB], config);

    const output = await fs.readFile(outputPath, 'utf-8');
    expect(countOccurrences(output, 'MARKER_FROM_ROOT_A')).toBe(1);
    expect(countOccurrences(output, 'MARKER_FROM_ROOT_B')).toBe(1);
    expect(countOccurrences(output, 'ROOT_A_SRC_MARKER')).toBe(1);
    expect(countOccurrences(output, 'ROOT_B_SRC_MARKER')).toBe(1);
  });

  it('preserves duplicate relative paths in json output with unique keys', async () => {
    const config = buildMergedConfig(outputDir, outputPath, 'json');
    await runPack([rootA, rootB], config);

    const output = await fs.readFile(outputPath, 'utf-8');
    const parsed = JSON.parse(output) as { files: Record<string, string> };

    expect(Object.keys(parsed.files).sort()).toEqual([
      'app-2/README.md',
      'app-2/src/index.ts',
      'app/README.md',
      'app/src/index.ts',
    ]);
    // Verify each disambiguated key maps to its own root's content (rootA -> app,
    // rootB -> app-2), not just that all markers appear somewhere in the values.
    expect(parsed.files['app/README.md']).toContain('MARKER_FROM_ROOT_A');
    expect(parsed.files['app/src/index.ts']).toContain('ROOT_A_SRC_MARKER');
    expect(parsed.files['app-2/README.md']).toContain('MARKER_FROM_ROOT_B');
    expect(parsed.files['app-2/src/index.ts']).toContain('ROOT_B_SRC_MARKER');
  });

  it('uses cwd-relative file paths in xml output when requested', async () => {
    const config = buildMergedConfig(outputDir, outputPath, 'xml', {
      output: { filePathStyle: 'cwd-relative' },
    });
    await runPack([rootA], config);

    const output = await fs.readFile(outputPath, 'utf-8');
    const expectedReadmePath = toDisplayPath(path.relative(outputDir, path.join(rootA, 'README.md')));
    const expectedSrcPath = toDisplayPath(path.relative(outputDir, path.join(rootA, 'src', 'index.ts')));

    expect(output).toContain(`<file path="${expectedReadmePath}">`);
    expect(output).toContain(`<file path="${expectedSrcPath}">`);
    expect(output).not.toContain('<file path="README.md">');
    expect(output).not.toContain('<file path="src/index.ts">');
  });

  it('uses cwd-relative file keys in json output for multiple roots when requested', async () => {
    const config = buildMergedConfig(outputDir, outputPath, 'json', {
      output: { filePathStyle: 'cwd-relative' },
    });
    await runPack([rootA, rootB], config);

    const output = await fs.readFile(outputPath, 'utf-8');
    const parsed = JSON.parse(output) as { files: Record<string, string> };

    const expectedKeys = [
      path.join(rootA, 'README.md'),
      path.join(rootA, 'src', 'index.ts'),
      path.join(rootB, 'README.md'),
      path.join(rootB, 'src', 'index.ts'),
    ].map((filePath) => toDisplayPath(path.relative(outputDir, filePath)));

    expect(Object.keys(parsed.files).sort()).toEqual(expectedKeys.sort());
    expect(parsed.files[toDisplayPath(path.relative(outputDir, path.join(rootA, 'README.md')))]).toContain(
      'MARKER_FROM_ROOT_A',
    );
    expect(parsed.files[toDisplayPath(path.relative(outputDir, path.join(rootB, 'README.md')))]).toContain(
      'MARKER_FROM_ROOT_B',
    );
  });

  it('reports the real file count for duplicate-relative-path multi-root inputs', async () => {
    const config = buildMergedConfig(outputDir, outputPath, 'xml');
    const result = await runPack([rootA, rootB], config);

    expect(result.totalFiles).toBe(4);
    expect(result.processedFiles).toHaveLength(4);
    expect(Object.keys(result.fileCharCounts)).toHaveLength(4);
  });
});