/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import { describe, it, expect, vi, beforeEach, afterEach, } from 'vitest';
import * as actualNodeFs from 'node:fs'; // For setup/teardown
import fs from 'node:fs';
import fsPromises from 'node:fs/promises';
import path from 'node:path';
import os from 'node:os';
import { fileURLToPath } from 'node:url';
// eslint-disable-next-line import/no-internal-modules
import mime from 'mime/lite';
import { isWithinRoot, isBinaryFile, detectFileType, processSingleFileContent, detectBOM, readFileWithEncoding, fileExists, readWasmBinaryFromDisk, saveTruncatedToolOutput, formatTruncatedToolOutput, } from './fileUtils.js';
import { StandardFileSystemService } from '../services/fileSystemService.js';
vi.mock('mime/lite', () => ({
    default: { getType: vi.fn() },
    getType: vi.fn(),
}));
const mockMimeGetType = mime.getType;
describe('fileUtils', () => {
    let tempRootDir;
    const originalProcessCwd = process.cwd;
    let testTextFilePath;
    let testImageFilePath;
    let testPdfFilePath;
    let testAudioFilePath;
    let testBinaryFilePath;
    let nonexistentFilePath;
    let directoryPath;
    beforeEach(() => {
        vi.resetAllMocks(); // Reset all mocks, including mime.getType
        tempRootDir = actualNodeFs.mkdtempSync(path.join(os.tmpdir(), 'fileUtils-test-'));
        process.cwd = vi.fn(() => tempRootDir); // Mock cwd if necessary for relative path logic within tests
        testTextFilePath = path.join(tempRootDir, 'test.txt');
        testImageFilePath = path.join(tempRootDir, 'image.png');
        testPdfFilePath = path.join(tempRootDir, 'document.pdf');
        testAudioFilePath = path.join(tempRootDir, 'audio.mp3');
        testBinaryFilePath = path.join(tempRootDir, 'app.exe');
        nonexistentFilePath = path.join(tempRootDir, 'nonexistent.txt');
        directoryPath = path.join(tempRootDir, 'subdir');
        actualNodeFs.mkdirSync(directoryPath, { recursive: true }); // Ensure subdir exists
    });
    afterEach(() => {
        if (actualNodeFs.existsSync(tempRootDir)) {
            actualNodeFs.rmSync(tempRootDir, { recursive: true, force: true });
        }
        process.cwd = originalProcessCwd;
        vi.restoreAllMocks(); // Restore any spies
    });
    describe('readWasmBinaryFromDisk', () => {
        it('loads a WASM binary from disk as a Uint8Array', async () => {
            const wasmFixtureUrl = new URL('./__fixtures__/dummy.wasm', import.meta.url);
            const wasmFixturePath = fileURLToPath(wasmFixtureUrl);
            const result = await readWasmBinaryFromDisk(wasmFixturePath);
            const expectedBytes = new Uint8Array(await fsPromises.readFile(wasmFixturePath));
            expect(result).toBeInstanceOf(Uint8Array);
            expect(result).toStrictEqual(expectedBytes);
        });
    });
    describe('isWithinRoot', () => {
        const defaultRoot = path.resolve('/project/root');
        it.each([
            {
                name: 'a path directly within the root',
                path: path.join(defaultRoot, 'file.txt'),
                expected: true,
            },
            {
                name: 'a path in a subdirectory within the root',
                path: path.join(defaultRoot, 'subdir', 'file.txt'),
                expected: true,
            },
            { name: 'the root path itself', path: defaultRoot, expected: true },
            {
                name: 'a path with a trailing slash',
                path: path.join(defaultRoot, 'file.txt') + path.sep,
                expected: true,
            },
            {
                name: 'the root path with a trailing slash',
                path: defaultRoot + path.sep,
                expected: true,
            },
            {
                name: 'a sub-path of the path to check',
                path: path.resolve('/project/root/sub'),
                root: path.resolve('/project/root'),
                expected: true,
            },
            {
                name: 'a path outside the root',
                path: path.resolve('/project/other', 'file.txt'),
                expected: false,
            },
            {
                name: 'an unrelated path',
                path: path.resolve('/unrelated', 'file.txt'),
                expected: false,
            },
            {
                name: 'a path that only partially matches the root prefix',
                path: path.resolve('/project/root-but-actually-different'),
                expected: false,
            },
            {
                name: 'a root path that is a sub-path of the path to check',
                path: path.resolve('/project/root'),
                root: path.resolve('/project/root/sub'),
                expected: false,
            },
            {
                name: 'a POSIX path inside',
                path: '/project/root/file.txt',
                root: '/project/root',
                expected: true,
            },
            {
                name: 'a POSIX path outside',
                path: '/project/other/file.txt',
                root: '/project/root',
                expected: false,
            },
        ])('should return $expected for $name', ({ path: testPath, root, expected }) => {
            expect(isWithinRoot(testPath, root || defaultRoot)).toBe(expected);
        });
    });
    describe('fileExists', () => {
        it('should return true if the file exists', async () => {
            const testFile = path.join(tempRootDir, 'exists.txt');
            actualNodeFs.writeFileSync(testFile, 'content');
            await expect(fileExists(testFile)).resolves.toBe(true);
        });
        it('should return false if the file does not exist', async () => {
            const testFile = path.join(tempRootDir, 'does-not-exist.txt');
            await expect(fileExists(testFile)).resolves.toBe(false);
        });
        it('should return true for a directory that exists', async () => {
            const testDir = path.join(tempRootDir, 'exists-dir');
            actualNodeFs.mkdirSync(testDir);
            await expect(fileExists(testDir)).resolves.toBe(true);
        });
    });
    describe('isBinaryFile', () => {
        let filePathForBinaryTest;
        beforeEach(() => {
            filePathForBinaryTest = path.join(tempRootDir, 'binaryCheck.tmp');
        });
        afterEach(() => {
            if (actualNodeFs.existsSync(filePathForBinaryTest)) {
                actualNodeFs.unlinkSync(filePathForBinaryTest);
            }
        });
        it('should return false for an empty file', async () => {
            actualNodeFs.writeFileSync(filePathForBinaryTest, '');
            expect(await isBinaryFile(filePathForBinaryTest)).toBe(false);
        });
        it('should return false for a typical text file', async () => {
            actualNodeFs.writeFileSync(filePathForBinaryTest, 'Hello, world!\nThis is a test file with normal text content.');
            expect(await isBinaryFile(filePathForBinaryTest)).toBe(false);
        });
        it('should return true for a file with many null bytes', async () => {
            const binaryContent = Buffer.from([
                0x48, 0x65, 0x00, 0x6c, 0x6f, 0x00, 0x00, 0x00, 0x00, 0x00,
            ]); // "He\0llo\0\0\0\0\0"
            actualNodeFs.writeFileSync(filePathForBinaryTest, binaryContent);
            expect(await isBinaryFile(filePathForBinaryTest)).toBe(true);
        });
        it('should return true for a file with high percentage of non-printable ASCII', async () => {
            const binaryContent = Buffer.from([
                0x41, 0x42, 0x01, 0x02, 0x03, 0x04, 0x05, 0x43, 0x44, 0x06,
            ]); // AB\x01\x02\x03\x04\x05CD\x06
            actualNodeFs.writeFileSync(filePathForBinaryTest, binaryContent);
            expect(await isBinaryFile(filePathForBinaryTest)).toBe(true);
        });
        it('should return false if file access fails (e.g., ENOENT)', async () => {
            // Ensure the file does not exist
            if (actualNodeFs.existsSync(filePathForBinaryTest)) {
                actualNodeFs.unlinkSync(filePathForBinaryTest);
            }
            expect(await isBinaryFile(filePathForBinaryTest)).toBe(false);
        });
    });
    describe('BOM detection and encoding', () => {
        let testDir;
        beforeEach(async () => {
            testDir = await fsPromises.mkdtemp(path.join(await fsPromises.realpath(os.tmpdir()), 'fileUtils-bom-test-'));
        });
        afterEach(async () => {
            if (testDir) {
                await fsPromises.rm(testDir, { recursive: true, force: true });
            }
        });
        describe('detectBOM', () => {
            it('should detect UTF-8 BOM', () => {
                const buf = Buffer.from([
                    0xef, 0xbb, 0xbf, 0x48, 0x65, 0x6c, 0x6c, 0x6f,
                ]);
                const result = detectBOM(buf);
                expect(result).toEqual({ encoding: 'utf8', bomLength: 3 });
            });
            it('should detect UTF-16 LE BOM', () => {
                const buf = Buffer.from([0xff, 0xfe, 0x48, 0x00, 0x65, 0x00]);
                const result = detectBOM(buf);
                expect(result).toEqual({ encoding: 'utf16le', bomLength: 2 });
            });
            it('should detect UTF-16 BE BOM', () => {
                const buf = Buffer.from([0xfe, 0xff, 0x00, 0x48, 0x00, 0x65]);
                const result = detectBOM(buf);
                expect(result).toEqual({ encoding: 'utf16be', bomLength: 2 });
            });
            it('should detect UTF-32 LE BOM', () => {
                const buf = Buffer.from([
                    0xff, 0xfe, 0x00, 0x00, 0x48, 0x00, 0x00, 0x00,
                ]);
                const result = detectBOM(buf);
                expect(result).toEqual({ encoding: 'utf32le', bomLength: 4 });
            });
            it('should detect UTF-32 BE BOM', () => {
                const buf = Buffer.from([
                    0x00, 0x00, 0xfe, 0xff, 0x00, 0x00, 0x00, 0x48,
                ]);
                const result = detectBOM(buf);
                expect(result).toEqual({ encoding: 'utf32be', bomLength: 4 });
            });
            it('should return null for no BOM', () => {
                const buf = Buffer.from([0x48, 0x65, 0x6c, 0x6c, 0x6f]);
                const result = detectBOM(buf);
                expect(result).toBeNull();
            });
            it('should return null for empty buffer', () => {
                const buf = Buffer.alloc(0);
                const result = detectBOM(buf);
                expect(result).toBeNull();
            });
            it('should return null for partial BOM', () => {
                const buf = Buffer.from([0xef, 0xbb]); // Incomplete UTF-8 BOM
                const result = detectBOM(buf);
                expect(result).toBeNull();
            });
        });
        describe('readFileWithEncoding', () => {
            it('should read UTF-8 BOM file correctly', async () => {
                const content = 'Hello, 世界! 🌍';
                const utf8Bom = Buffer.from([0xef, 0xbb, 0xbf]);
                const utf8Content = Buffer.from(content, 'utf8');
                const fullBuffer = Buffer.concat([utf8Bom, utf8Content]);
                const filePath = path.join(testDir, 'utf8-bom.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await readFileWithEncoding(filePath);
                expect(result).toBe(content);
            });
            it('should read UTF-16 LE BOM file correctly', async () => {
                const content = 'Hello, 世界! 🌍';
                const utf16leBom = Buffer.from([0xff, 0xfe]);
                const utf16leContent = Buffer.from(content, 'utf16le');
                const fullBuffer = Buffer.concat([utf16leBom, utf16leContent]);
                const filePath = path.join(testDir, 'utf16le-bom.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await readFileWithEncoding(filePath);
                expect(result).toBe(content);
            });
            it('should read UTF-16 BE BOM file correctly', async () => {
                const content = 'Hello, 世界! 🌍';
                // Manually encode UTF-16 BE: each char as big-endian 16-bit
                const utf16beBom = Buffer.from([0xfe, 0xff]);
                const chars = Array.from(content);
                const utf16beBytes = [];
                for (const char of chars) {
                    const code = char.codePointAt(0);
                    if (code > 0xffff) {
                        // Surrogate pair for emoji
                        const surrogate1 = 0xd800 + ((code - 0x10000) >> 10);
                        const surrogate2 = 0xdc00 + ((code - 0x10000) & 0x3ff);
                        utf16beBytes.push((surrogate1 >> 8) & 0xff, surrogate1 & 0xff);
                        utf16beBytes.push((surrogate2 >> 8) & 0xff, surrogate2 & 0xff);
                    }
                    else {
                        utf16beBytes.push((code >> 8) & 0xff, code & 0xff);
                    }
                }
                const utf16beContent = Buffer.from(utf16beBytes);
                const fullBuffer = Buffer.concat([utf16beBom, utf16beContent]);
                const filePath = path.join(testDir, 'utf16be-bom.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await readFileWithEncoding(filePath);
                expect(result).toBe(content);
            });
            it('should read UTF-32 LE BOM file correctly', async () => {
                const content = 'Hello, 世界! 🌍';
                const utf32leBom = Buffer.from([0xff, 0xfe, 0x00, 0x00]);
                const utf32leBytes = [];
                for (const char of Array.from(content)) {
                    const code = char.codePointAt(0);
                    utf32leBytes.push(code & 0xff, (code >> 8) & 0xff, (code >> 16) & 0xff, (code >> 24) & 0xff);
                }
                const utf32leContent = Buffer.from(utf32leBytes);
                const fullBuffer = Buffer.concat([utf32leBom, utf32leContent]);
                const filePath = path.join(testDir, 'utf32le-bom.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await readFileWithEncoding(filePath);
                expect(result).toBe(content);
            });
            it('should read UTF-32 BE BOM file correctly', async () => {
                const content = 'Hello, 世界! 🌍';
                const utf32beBom = Buffer.from([0x00, 0x00, 0xfe, 0xff]);
                const utf32beBytes = [];
                for (const char of Array.from(content)) {
                    const code = char.codePointAt(0);
                    utf32beBytes.push((code >> 24) & 0xff, (code >> 16) & 0xff, (code >> 8) & 0xff, code & 0xff);
                }
                const utf32beContent = Buffer.from(utf32beBytes);
                const fullBuffer = Buffer.concat([utf32beBom, utf32beContent]);
                const filePath = path.join(testDir, 'utf32be-bom.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await readFileWithEncoding(filePath);
                expect(result).toBe(content);
            });
            it('should read file without BOM as UTF-8', async () => {
                const content = 'Hello, 世界!';
                const filePath = path.join(testDir, 'no-bom.txt');
                await fsPromises.writeFile(filePath, content, 'utf8');
                const result = await readFileWithEncoding(filePath);
                expect(result).toBe(content);
            });
            it('should handle empty file', async () => {
                const filePath = path.join(testDir, 'empty.txt');
                await fsPromises.writeFile(filePath, '');
                const result = await readFileWithEncoding(filePath);
                expect(result).toBe('');
            });
        });
        describe('isBinaryFile with BOM awareness', () => {
            it('should not treat UTF-8 BOM file as binary', async () => {
                const content = 'Hello, world!';
                const utf8Bom = Buffer.from([0xef, 0xbb, 0xbf]);
                const utf8Content = Buffer.from(content, 'utf8');
                const fullBuffer = Buffer.concat([utf8Bom, utf8Content]);
                const filePath = path.join(testDir, 'utf8-bom-test.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await isBinaryFile(filePath);
                expect(result).toBe(false);
            });
            it('should not treat UTF-16 LE BOM file as binary', async () => {
                const content = 'Hello, world!';
                const utf16leBom = Buffer.from([0xff, 0xfe]);
                const utf16leContent = Buffer.from(content, 'utf16le');
                const fullBuffer = Buffer.concat([utf16leBom, utf16leContent]);
                const filePath = path.join(testDir, 'utf16le-bom-test.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await isBinaryFile(filePath);
                expect(result).toBe(false);
            });
            it('should not treat UTF-16 BE BOM file as binary', async () => {
                const utf16beBom = Buffer.from([0xfe, 0xff]);
                // Simple ASCII in UTF-16 BE
                const utf16beContent = Buffer.from([
                    0x00,
                    0x48, // H
                    0x00,
                    0x65, // e
                    0x00,
                    0x6c, // l
                    0x00,
                    0x6c, // l
                    0x00,
                    0x6f, // o
                    0x00,
                    0x2c, // ,
                    0x00,
                    0x20, // space
                    0x00,
                    0x77, // w
                    0x00,
                    0x6f, // o
                    0x00,
                    0x72, // r
                    0x00,
                    0x6c, // l
                    0x00,
                    0x64, // d
                    0x00,
                    0x21, // !
                ]);
                const fullBuffer = Buffer.concat([utf16beBom, utf16beContent]);
                const filePath = path.join(testDir, 'utf16be-bom-test.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await isBinaryFile(filePath);
                expect(result).toBe(false);
            });
            it('should not treat UTF-32 LE BOM file as binary', async () => {
                const utf32leBom = Buffer.from([0xff, 0xfe, 0x00, 0x00]);
                const utf32leContent = Buffer.from([
                    0x48,
                    0x00,
                    0x00,
                    0x00, // H
                    0x65,
                    0x00,
                    0x00,
                    0x00, // e
                    0x6c,
                    0x00,
                    0x00,
                    0x00, // l
                    0x6c,
                    0x00,
                    0x00,
                    0x00, // l
                    0x6f,
                    0x00,
                    0x00,
                    0x00, // o
                ]);
                const fullBuffer = Buffer.concat([utf32leBom, utf32leContent]);
                const filePath = path.join(testDir, 'utf32le-bom-test.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await isBinaryFile(filePath);
                expect(result).toBe(false);
            });
            it('should not treat UTF-32 BE BOM file as binary', async () => {
                const utf32beBom = Buffer.from([0x00, 0x00, 0xfe, 0xff]);
                const utf32beContent = Buffer.from([
                    0x00,
                    0x00,
                    0x00,
                    0x48, // H
                    0x00,
                    0x00,
                    0x00,
                    0x65, // e
                    0x00,
                    0x00,
                    0x00,
                    0x6c, // l
                    0x00,
                    0x00,
                    0x00,
                    0x6c, // l
                    0x00,
                    0x00,
                    0x00,
                    0x6f, // o
                ]);
                const fullBuffer = Buffer.concat([utf32beBom, utf32beContent]);
                const filePath = path.join(testDir, 'utf32be-bom-test.txt');
                await fsPromises.writeFile(filePath, fullBuffer);
                const result = await isBinaryFile(filePath);
                expect(result).toBe(false);
            });
            it('should still treat actual binary file as binary', async () => {
                // PNG header + some binary data with null bytes
                const pngHeader = Buffer.from([
                    0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a,
                ]);
                const binaryData = Buffer.from([
                    0x00, 0x00, 0x00, 0x0d, 0x49, 0x48, 0x44, 0x52,
                ]); // IHDR chunk with nulls
                const fullContent = Buffer.concat([pngHeader, binaryData]);
                const filePath = path.join(testDir, 'test.png');
                await fsPromises.writeFile(filePath, fullContent);
                const result = await isBinaryFile(filePath);
                expect(result).toBe(true);
            });
            it('should treat file with null bytes (no BOM) as binary', async () => {
                const content = Buffer.from([
                    0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x00, 0x77, 0x6f, 0x72, 0x6c, 0x64,
                ]);
                const filePath = path.join(testDir, 'null-bytes.bin');
                await fsPromises.writeFile(filePath, content);
                const result = await isBinaryFile(filePath);
                expect(result).toBe(true);
            });
        });
    });
    describe('detectFileType', () => {
        let filePathForDetectTest;
        beforeEach(() => {
            filePathForDetectTest = path.join(tempRootDir, 'detectType.tmp');
            // Default: create as a text file for isBinaryFile fallback
            actualNodeFs.writeFileSync(filePathForDetectTest, 'Plain text content');
        });
        afterEach(() => {
            if (actualNodeFs.existsSync(filePathForDetectTest)) {
                actualNodeFs.unlinkSync(filePathForDetectTest);
            }
            vi.restoreAllMocks(); // Restore spies on actualNodeFs
        });
        it('should detect typescript type by extension (ts, mts, cts, tsx)', async () => {
            expect(await detectFileType('file.ts')).toBe('text');
            expect(await detectFileType('file.test.ts')).toBe('text');
            expect(await detectFileType('file.mts')).toBe('text');
            expect(await detectFileType('vite.config.mts')).toBe('text');
            expect(await detectFileType('file.cts')).toBe('text');
            expect(await detectFileType('component.tsx')).toBe('text');
        });
        it.each([
            { type: 'image', file: 'file.png', mime: 'image/png' },
            { type: 'image', file: 'file.jpg', mime: 'image/jpeg' },
            { type: 'pdf', file: 'file.pdf', mime: 'application/pdf' },
            { type: 'binary', file: 'archive.zip', mime: 'application/zip' },
            { type: 'binary', file: 'app.exe', mime: 'application/octet-stream' },
        ])('should detect $type type for $file by extension', async ({ file, mime, type }) => {
            mockMimeGetType.mockReturnValueOnce(mime);
            expect(await detectFileType(file)).toBe(type);
        });
        it.each([
            { type: 'audio', ext: '.mp3', mime: 'audio/mpeg' },
            { type: 'video', ext: '.mp4', mime: 'video/mp4' },
        ])('should detect $type type for binary files with $ext extension', async ({ type, ext, mime }) => {
            const filePath = path.join(tempRootDir, `test${ext}`);
            const binaryContent = Buffer.from([
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            ]);
            actualNodeFs.writeFileSync(filePath, binaryContent);
            mockMimeGetType.mockReturnValueOnce(mime);
            expect(await detectFileType(filePath)).toBe(type);
            actualNodeFs.unlinkSync(filePath);
        });
        it('should detect svg type by extension', async () => {
            expect(await detectFileType('image.svg')).toBe('svg');
            expect(await detectFileType('image.icon.svg')).toBe('svg');
        });
        it('should use isBinaryFile for unknown extensions and detect as binary', async () => {
            mockMimeGetType.mockReturnValueOnce(false); // Unknown mime type
            // Create a file that isBinaryFile will identify as binary
            const binaryContent = Buffer.from([
                0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a,
            ]);
            actualNodeFs.writeFileSync(filePathForDetectTest, binaryContent);
            expect(await detectFileType(filePathForDetectTest)).toBe('binary');
        });
        it('should default to text if mime type is unknown and content is not binary', async () => {
            mockMimeGetType.mockReturnValueOnce(false); // Unknown mime type
            // filePathForDetectTest is already a text file by default from beforeEach
            expect(await detectFileType(filePathForDetectTest)).toBe('text');
        });
        it('should detect .adp files with XML content as text, not audio (#16888)', async () => {
            const adpFilePath = path.join(tempRootDir, 'test.adp');
            const xmlContent = `<?xml version="1.0" encoding="UTF-8"?>
<AdapterType Name="ATimeOut" Comment="Adapter for timed events">
  <InterfaceList>
    <EventInputs>
      <Event Name="TimeOut"/>
    </EventInputs>
  </InterfaceList>
</AdapterType>`;
            actualNodeFs.writeFileSync(adpFilePath, xmlContent);
            mockMimeGetType.mockReturnValueOnce('audio/adpcm');
            expect(await detectFileType(adpFilePath)).toBe('text');
            actualNodeFs.unlinkSync(adpFilePath);
        });
    });
    describe('processSingleFileContent', () => {
        beforeEach(() => {
            // Ensure files exist for statSync checks before readFile might be mocked
            if (actualNodeFs.existsSync(testTextFilePath))
                actualNodeFs.unlinkSync(testTextFilePath);
            if (actualNodeFs.existsSync(testImageFilePath))
                actualNodeFs.unlinkSync(testImageFilePath);
            if (actualNodeFs.existsSync(testPdfFilePath))
                actualNodeFs.unlinkSync(testPdfFilePath);
            if (actualNodeFs.existsSync(testAudioFilePath))
                actualNodeFs.unlinkSync(testAudioFilePath);
            if (actualNodeFs.existsSync(testBinaryFilePath))
                actualNodeFs.unlinkSync(testBinaryFilePath);
        });
        it('should read a text file successfully', async () => {
            const content = 'Line 1\\nLine 2\\nLine 3';
            actualNodeFs.writeFileSync(testTextFilePath, content);
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.llmContent).toBe(content);
            expect(result.returnDisplay).toBe('');
            expect(result.error).toBeUndefined();
        });
        it('should handle file not found', async () => {
            const result = await processSingleFileContent(nonexistentFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.error).toContain('File not found');
            expect(result.returnDisplay).toContain('File not found');
        });
        it('should handle read errors for text files', async () => {
            actualNodeFs.writeFileSync(testTextFilePath, 'content'); // File must exist for initial statSync
            const readError = new Error('Simulated read error');
            vi.spyOn(fsPromises, 'readFile').mockRejectedValueOnce(readError);
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.error).toContain('Simulated read error');
            expect(result.returnDisplay).toContain('Simulated read error');
        });
        it('should handle read errors for image/pdf files', async () => {
            actualNodeFs.writeFileSync(testImageFilePath, 'content'); // File must exist
            mockMimeGetType.mockReturnValue('image/png');
            const readError = new Error('Simulated image read error');
            vi.spyOn(fsPromises, 'readFile').mockRejectedValueOnce(readError);
            const result = await processSingleFileContent(testImageFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.error).toContain('Simulated image read error');
            expect(result.returnDisplay).toContain('Simulated image read error');
        });
        it('should process an image file', async () => {
            const fakePngData = Buffer.from('fake png data');
            actualNodeFs.writeFileSync(testImageFilePath, fakePngData);
            mockMimeGetType.mockReturnValue('image/png');
            const result = await processSingleFileContent(testImageFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.llmContent.inlineData).toBeDefined();
            expect(result.llmContent.inlineData
                .mimeType).toBe('image/png');
            expect(result.llmContent.inlineData.data).toBe(fakePngData.toString('base64'));
            expect(result.returnDisplay).toContain('Read image file: image.png');
        });
        it('should process a PDF file', async () => {
            const fakePdfData = Buffer.from('fake pdf data');
            actualNodeFs.writeFileSync(testPdfFilePath, fakePdfData);
            mockMimeGetType.mockReturnValue('application/pdf');
            const result = await processSingleFileContent(testPdfFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.llmContent.inlineData).toBeDefined();
            expect(result.llmContent.inlineData
                .mimeType).toBe('application/pdf');
            expect(result.llmContent.inlineData.data).toBe(fakePdfData.toString('base64'));
            expect(result.returnDisplay).toContain('Read pdf file: document.pdf');
        });
        it('should process an audio file', async () => {
            const fakeMp3Data = Buffer.from([
                0x49, 0x44, 0x33, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00,
            ]);
            actualNodeFs.writeFileSync(testAudioFilePath, fakeMp3Data);
            mockMimeGetType.mockReturnValue('audio/mpeg');
            const result = await processSingleFileContent(testAudioFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.llmContent.inlineData).toBeDefined();
            expect(result.llmContent.inlineData
                .mimeType).toBe('audio/mpeg');
            expect(result.llmContent.inlineData.data).toBe(fakeMp3Data.toString('base64'));
            expect(result.returnDisplay).toContain('Read audio file: audio.mp3');
        });
        it('should read an SVG file as text when under 1MB', async () => {
            const svgContent = `
    <svg xmlns="http://www.w3.org/2000/svg" width="100" height="100">
      <rect width="100" height="100" fill="blue" />
    </svg>
  `;
            const testSvgFilePath = path.join(tempRootDir, 'test.svg');
            actualNodeFs.writeFileSync(testSvgFilePath, svgContent, 'utf-8');
            mockMimeGetType.mockReturnValue('image/svg+xml');
            const result = await processSingleFileContent(testSvgFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.llmContent).toBe(svgContent);
            expect(result.returnDisplay).toContain('Read SVG as text');
        });
        it('should skip binary files', async () => {
            actualNodeFs.writeFileSync(testBinaryFilePath, Buffer.from([0x00, 0x01, 0x02]));
            mockMimeGetType.mockReturnValueOnce('application/octet-stream');
            // isBinaryFile will operate on the real file.
            const result = await processSingleFileContent(testBinaryFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.llmContent).toContain('Cannot display content of binary file');
            expect(result.returnDisplay).toContain('Skipped binary file: app.exe');
        });
        it('should handle path being a directory', async () => {
            const result = await processSingleFileContent(directoryPath, tempRootDir, new StandardFileSystemService());
            expect(result.error).toContain('Path is a directory');
            expect(result.returnDisplay).toContain('Path is a directory');
        });
        it('should paginate text files correctly (offset and limit)', async () => {
            const lines = Array.from({ length: 20 }, (_, i) => `Line ${i + 1}`);
            actualNodeFs.writeFileSync(testTextFilePath, lines.join('\n'));
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService(), 5, 5); // Read lines 6-10
            const expectedContent = lines.slice(5, 10).join('\n');
            expect(result.llmContent).toBe(expectedContent);
            expect(result.returnDisplay).toBe('Read lines 6-10 of 20 from test.txt');
            expect(result.isTruncated).toBe(true);
            expect(result.originalLineCount).toBe(20);
            expect(result.linesShown).toEqual([6, 10]);
        });
        it('should identify truncation when reading the end of a file', async () => {
            const lines = Array.from({ length: 20 }, (_, i) => `Line ${i + 1}`);
            actualNodeFs.writeFileSync(testTextFilePath, lines.join('\n'));
            // Read from line 11 to 20. The start is not 0, so it's truncated.
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService(), 10, 10);
            const expectedContent = lines.slice(10, 20).join('\n');
            expect(result.llmContent).toContain(expectedContent);
            expect(result.returnDisplay).toBe('Read lines 11-20 of 20 from test.txt');
            expect(result.isTruncated).toBe(true); // This is the key check for the bug
            expect(result.originalLineCount).toBe(20);
            expect(result.linesShown).toEqual([11, 20]);
        });
        it('should handle limit exceeding file length', async () => {
            const lines = ['Line 1', 'Line 2'];
            actualNodeFs.writeFileSync(testTextFilePath, lines.join('\n'));
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService(), 0, 10);
            const expectedContent = lines.join('\n');
            expect(result.llmContent).toBe(expectedContent);
            expect(result.returnDisplay).toBe('');
            expect(result.isTruncated).toBe(false);
            expect(result.originalLineCount).toBe(2);
            expect(result.linesShown).toEqual([1, 2]);
        });
        it('should truncate long lines in text files', async () => {
            const longLine = 'a'.repeat(2500);
            actualNodeFs.writeFileSync(testTextFilePath, `Short line\n${longLine}\nAnother short line`);
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService());
            expect(result.llmContent).toContain('Short line');
            expect(result.llmContent).toContain(longLine.substring(0, 2000) + '... [truncated]');
            expect(result.llmContent).toContain('Another short line');
            expect(result.returnDisplay).toBe('Read all 3 lines from test.txt (some lines were shortened)');
            expect(result.isTruncated).toBe(true);
        });
        it('should truncate when line count exceeds the limit', async () => {
            const lines = Array.from({ length: 11 }, (_, i) => `Line ${i + 1}`);
            actualNodeFs.writeFileSync(testTextFilePath, lines.join('\n'));
            // Read 5 lines, but there are 11 total
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService(), 0, 5);
            expect(result.isTruncated).toBe(true);
            expect(result.returnDisplay).toBe('Read lines 1-5 of 11 from test.txt');
        });
        it('should truncate when a line length exceeds the character limit', async () => {
            const longLine = 'b'.repeat(2500);
            const lines = Array.from({ length: 10 }, (_, i) => `Line ${i + 1}`);
            lines.push(longLine); // Total 11 lines
            actualNodeFs.writeFileSync(testTextFilePath, lines.join('\n'));
            // Read all 11 lines, including the long one
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService(), 0, 11);
            expect(result.isTruncated).toBe(true);
            expect(result.returnDisplay).toBe('Read all 11 lines from test.txt (some lines were shortened)');
        });
        it('should truncate both line count and line length when both exceed limits', async () => {
            const linesWithLongInMiddle = Array.from({ length: 20 }, (_, i) => `Line ${i + 1}`);
            linesWithLongInMiddle[4] = 'c'.repeat(2500);
            actualNodeFs.writeFileSync(testTextFilePath, linesWithLongInMiddle.join('\n'));
            // Read 10 lines out of 20, including the long line
            const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService(), 0, 10);
            expect(result.isTruncated).toBe(true);
            expect(result.returnDisplay).toBe('Read lines 1-10 of 20 from test.txt (some lines were shortened)');
        });
        it('should return an error if the file size exceeds 20MB', async () => {
            // Create a small test file
            actualNodeFs.writeFileSync(testTextFilePath, 'test content');
            // Spy on fs.promises.stat to return a large file size
            const statSpy = vi.spyOn(fs.promises, 'stat').mockResolvedValueOnce({
                size: 21 * 1024 * 1024,
                isDirectory: () => false,
            });
            try {
                const result = await processSingleFileContent(testTextFilePath, tempRootDir, new StandardFileSystemService());
                expect(result.error).toContain('File size exceeds the 20MB limit');
                expect(result.returnDisplay).toContain('File size exceeds the 20MB limit');
                expect(result.llmContent).toContain('File size exceeds the 20MB limit');
            }
            finally {
                statSpy.mockRestore();
            }
        });
    });
    describe('saveTruncatedToolOutput & formatTruncatedToolOutput', () => {
        it('should save content to a file with safe name', async () => {
            const content = 'some content';
            const toolName = 'shell';
            const id = '123';
            const result = await saveTruncatedToolOutput(content, toolName, id, tempRootDir);
            const expectedOutputFile = path.join(tempRootDir, 'shell_123.txt');
            expect(result.outputFile).toBe(expectedOutputFile);
            expect(result.totalLines).toBe(1);
            const savedContent = await fsPromises.readFile(expectedOutputFile, 'utf-8');
            expect(savedContent).toBe(content);
        });
        it('should sanitize tool name in filename', async () => {
            const content = 'content';
            const toolName = '../../dangerous/tool';
            const id = 1;
            const result = await saveTruncatedToolOutput(content, toolName, id, tempRootDir);
            // ../../dangerous/tool -> ______dangerous_tool
            const expectedOutputFile = path.join(tempRootDir, '______dangerous_tool_1.txt');
            expect(result.outputFile).toBe(expectedOutputFile);
        });
        it('should sanitize id in filename', async () => {
            const content = 'content';
            const toolName = 'shell';
            const id = '../../etc/passwd';
            const result = await saveTruncatedToolOutput(content, toolName, id, tempRootDir);
            // ../../etc/passwd -> ______etc_passwd
            const expectedOutputFile = path.join(tempRootDir, 'shell_______etc_passwd.txt');
            expect(result.outputFile).toBe(expectedOutputFile);
        });
        it('should format multi-line output correctly', () => {
            const lines = Array.from({ length: 50 }, (_, i) => `line ${i}`);
            const content = lines.join('\n');
            const outputFile = '/tmp/out.txt';
            const formatted = formatTruncatedToolOutput(content, outputFile, 10);
            expect(formatted).toContain('Output too large. Showing the last 10 of 50 lines.');
            expect(formatted).toContain('For full output see: /tmp/out.txt');
            expect(formatted).toContain('line 49');
            expect(formatted).not.toContain('line 0');
        });
        it('should truncate "elephant lines" (long single line in multi-line output)', () => {
            const longLine = 'a'.repeat(2000);
            const content = `line 1\n${longLine}\nline 3`;
            const outputFile = '/tmp/out.txt';
            const formatted = formatTruncatedToolOutput(content, outputFile, 3);
            expect(formatted).toContain('(some long lines truncated)');
            expect(formatted).toContain('... [LINE WIDTH TRUNCATED]');
            expect(formatted.length).toBeLessThan(longLine.length);
        });
        it('should handle massive single-line string with character-based truncation', () => {
            const content = 'a'.repeat(50000);
            const outputFile = '/tmp/out.txt';
            const formatted = formatTruncatedToolOutput(content, outputFile);
            expect(formatted).toContain('Output too large. Showing the last 4,000 characters');
            expect(formatted.endsWith(content.slice(-4000))).toBe(true);
        });
    });
});
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