/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import { vi, describe, it, expect, beforeEach, afterEach } from 'vitest';
import { execSync } from 'node:child_process';
import * as os from 'node:os';
import { detect as chardetDetect } from 'chardet';
import { debugLogger } from './debugLogger.js';
// Mock dependencies
vi.mock('child_process');
vi.mock('os');
vi.mock('chardet');
// Import the functions we want to test after refactoring
import { getCachedEncodingForBuffer, getSystemEncoding, windowsCodePageToEncoding, detectEncodingFromBuffer, resetEncodingCache, } from './systemEncoding.js';
describe('Shell Command Processor - Encoding Functions', () => {
    let consoleWarnSpy;
    let mockedExecSync;
    let mockedOsPlatform;
    let mockedChardetDetect;
    beforeEach(() => {
        consoleWarnSpy = vi.spyOn(debugLogger, 'warn').mockImplementation(() => { });
        mockedExecSync = vi.mocked(execSync);
        mockedOsPlatform = vi.mocked(os.platform);
        mockedChardetDetect = vi.mocked(chardetDetect);
        // Reset the encoding cache before each test
        resetEncodingCache();
        // Clear environment variables that might affect tests
        delete process.env['LC_ALL'];
        delete process.env['LC_CTYPE'];
        delete process.env['LANG'];
    });
    afterEach(() => {
        vi.restoreAllMocks();
        resetEncodingCache();
    });
    describe('windowsCodePageToEncoding', () => {
        it('should map common Windows code pages correctly', () => {
            expect(windowsCodePageToEncoding(437)).toBe('cp437');
            expect(windowsCodePageToEncoding(850)).toBe('cp850');
            expect(windowsCodePageToEncoding(65001)).toBe('utf-8');
            expect(windowsCodePageToEncoding(1252)).toBe('windows-1252');
            expect(windowsCodePageToEncoding(932)).toBe('shift_jis');
            expect(windowsCodePageToEncoding(936)).toBe('gb2312');
            expect(windowsCodePageToEncoding(949)).toBe('euc-kr');
            expect(windowsCodePageToEncoding(950)).toBe('big5');
            expect(windowsCodePageToEncoding(1200)).toBe('utf-16le');
            expect(windowsCodePageToEncoding(1201)).toBe('utf-16be');
        });
        it('should return null for unmapped code pages and warn', () => {
            expect(windowsCodePageToEncoding(99999)).toBe(null);
            expect(consoleWarnSpy).toHaveBeenCalledWith('Unable to determine encoding for windows code page 99999.');
        });
        it('should handle all Windows-specific code pages', () => {
            expect(windowsCodePageToEncoding(874)).toBe('windows-874');
            expect(windowsCodePageToEncoding(1250)).toBe('windows-1250');
            expect(windowsCodePageToEncoding(1251)).toBe('windows-1251');
            expect(windowsCodePageToEncoding(1253)).toBe('windows-1253');
            expect(windowsCodePageToEncoding(1254)).toBe('windows-1254');
            expect(windowsCodePageToEncoding(1255)).toBe('windows-1255');
            expect(windowsCodePageToEncoding(1256)).toBe('windows-1256');
            expect(windowsCodePageToEncoding(1257)).toBe('windows-1257');
            expect(windowsCodePageToEncoding(1258)).toBe('windows-1258');
        });
    });
    describe('detectEncodingFromBuffer', () => {
        it('should detect encoding using chardet successfully', () => {
            const buffer = Buffer.from('test content', 'utf8');
            mockedChardetDetect.mockReturnValue('UTF-8');
            const result = detectEncodingFromBuffer(buffer);
            expect(result).toBe('utf-8');
            expect(mockedChardetDetect).toHaveBeenCalledWith(buffer);
        });
        it('should handle chardet returning mixed case encoding', () => {
            const buffer = Buffer.from('test content', 'utf8');
            mockedChardetDetect.mockReturnValue('ISO-8859-1');
            const result = detectEncodingFromBuffer(buffer);
            expect(result).toBe('iso-8859-1');
        });
        it('should return null when chardet fails', () => {
            const buffer = Buffer.from('test content', 'utf8');
            mockedChardetDetect.mockImplementation(() => {
                throw new Error('Detection failed');
            });
            const result = detectEncodingFromBuffer(buffer);
            expect(result).toBe(null);
            expect(consoleWarnSpy).toHaveBeenCalledWith('Failed to detect encoding with chardet:', expect.any(Error));
        });
        it('should return null when chardet returns null', () => {
            const buffer = Buffer.from('test content', 'utf8');
            mockedChardetDetect.mockReturnValue(null);
            const result = detectEncodingFromBuffer(buffer);
            expect(result).toBe(null);
        });
        it('should return null when chardet returns non-string', () => {
            const buffer = Buffer.from('test content', 'utf8');
            mockedChardetDetect.mockReturnValue([
                'utf-8',
                'iso-8859-1',
            ]);
            const result = detectEncodingFromBuffer(buffer);
            expect(result).toBe(null);
        });
    });
    describe('getSystemEncoding - Windows', () => {
        beforeEach(() => {
            mockedOsPlatform.mockReturnValue('win32');
        });
        it('should parse Windows chcp output correctly', () => {
            mockedExecSync.mockReturnValue('Active code page: 65001');
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
            expect(mockedExecSync).toHaveBeenCalledWith('chcp', { encoding: 'utf8' });
        });
        it('should handle different chcp output formats', () => {
            mockedExecSync.mockReturnValue('Current code page: 1252');
            const result = getSystemEncoding();
            expect(result).toBe('windows-1252');
        });
        it('should handle chcp output with extra whitespace', () => {
            mockedExecSync.mockReturnValue('Active code page:   437   ');
            const result = getSystemEncoding();
            expect(result).toBe('cp437');
        });
        it('should return null when chcp command fails', () => {
            mockedExecSync.mockImplementation(() => {
                throw new Error('Command failed');
            });
            const result = getSystemEncoding();
            expect(result).toBe(null);
            expect(consoleWarnSpy).toHaveBeenCalledWith(expect.stringContaining("Failed to get Windows code page using 'chcp' command"));
        });
        it('should return null when chcp output cannot be parsed', () => {
            mockedExecSync.mockReturnValue('Unexpected output format');
            const result = getSystemEncoding();
            expect(result).toBe(null);
            expect(consoleWarnSpy).toHaveBeenCalledWith(expect.stringContaining("Failed to get Windows code page using 'chcp' command"));
        });
        it('should return null when code page is not a number', () => {
            mockedExecSync.mockReturnValue('Active code page: abc');
            const result = getSystemEncoding();
            expect(result).toBe(null);
            expect(consoleWarnSpy).toHaveBeenCalledWith(expect.stringContaining("Failed to get Windows code page using 'chcp' command"));
        });
        it('should return null when code page maps to null', () => {
            mockedExecSync.mockReturnValue('Active code page: 99999');
            const result = getSystemEncoding();
            expect(result).toBe(null);
            // Should warn about unknown code page from windowsCodePageToEncoding
            expect(consoleWarnSpy).toHaveBeenCalledWith('Unable to determine encoding for windows code page 99999.');
        });
    });
    describe('getSystemEncoding - Unix-like', () => {
        beforeEach(() => {
            mockedOsPlatform.mockReturnValue('linux');
        });
        it('should parse locale from LC_ALL environment variable', () => {
            process.env['LC_ALL'] = 'en_US.UTF-8';
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
        });
        it('should parse locale from LC_CTYPE when LC_ALL is not set', () => {
            process.env['LC_CTYPE'] = 'fr_FR.ISO-8859-1';
            const result = getSystemEncoding();
            expect(result).toBe('iso-8859-1');
        });
        it('should parse locale from LANG when LC_ALL and LC_CTYPE are not set', () => {
            process.env['LANG'] = 'de_DE.UTF-8';
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
        });
        it('should handle locale charmap command when environment variables are empty', () => {
            mockedExecSync.mockReturnValue('UTF-8\n');
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
            expect(mockedExecSync).toHaveBeenCalledWith('locale charmap', {
                encoding: 'utf8',
            });
        });
        it('should handle locale charmap with mixed case', () => {
            mockedExecSync.mockReturnValue('ISO-8859-1\n');
            const result = getSystemEncoding();
            expect(result).toBe('iso-8859-1');
        });
        it('should return null when locale charmap fails', () => {
            mockedExecSync.mockImplementation(() => {
                throw new Error('Command failed');
            });
            const result = getSystemEncoding();
            expect(result).toBe(null);
            expect(consoleWarnSpy).toHaveBeenCalledWith('Failed to get locale charmap.');
        });
        it('should handle locale without encoding (no dot)', () => {
            process.env['LANG'] = 'C';
            const result = getSystemEncoding();
            expect(result).toBe('c');
        });
        it('should handle empty locale environment variables', () => {
            process.env['LC_ALL'] = '';
            process.env['LC_CTYPE'] = '';
            process.env['LANG'] = '';
            mockedExecSync.mockReturnValue('UTF-8');
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
        });
        it('should return locale as-is when locale format has no dot', () => {
            process.env['LANG'] = 'invalid_format';
            const result = getSystemEncoding();
            expect(result).toBe('invalid_format');
        });
        it('should prioritize LC_ALL over other environment variables', () => {
            process.env['LC_ALL'] = 'en_US.UTF-8';
            process.env['LC_CTYPE'] = 'fr_FR.ISO-8859-1';
            process.env['LANG'] = 'de_DE.CP1252';
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
        });
        it('should prioritize LC_CTYPE over LANG', () => {
            process.env['LC_CTYPE'] = 'fr_FR.ISO-8859-1';
            process.env['LANG'] = 'de_DE.CP1252';
            const result = getSystemEncoding();
            expect(result).toBe('iso-8859-1');
        });
    });
    describe('getEncodingForBuffer', () => {
        beforeEach(() => {
            mockedOsPlatform.mockReturnValue('linux');
        });
        it('should use cached system encoding on subsequent calls', () => {
            process.env['LANG'] = 'en_US.UTF-8';
            const buffer = Buffer.from('test');
            // First call
            const result1 = getCachedEncodingForBuffer(buffer);
            expect(result1).toBe('utf-8');
            // Change environment (should not affect cached result)
            process.env['LANG'] = 'fr_FR.ISO-8859-1';
            // Second call should use cached value
            const result2 = getCachedEncodingForBuffer(buffer);
            expect(result2).toBe('utf-8');
        });
        it('should fall back to buffer detection when system encoding fails', () => {
            // No environment variables set
            mockedExecSync.mockImplementation(() => {
                throw new Error('locale command failed');
            });
            const buffer = Buffer.from('test');
            mockedChardetDetect.mockReturnValue('ISO-8859-1');
            const result = getCachedEncodingForBuffer(buffer);
            expect(result).toBe('iso-8859-1');
            expect(mockedChardetDetect).toHaveBeenCalledWith(buffer);
        });
        it('should fall back to utf-8 when both system and buffer detection fail', () => {
            // System encoding fails
            mockedExecSync.mockImplementation(() => {
                throw new Error('locale command failed');
            });
            // Buffer detection fails
            mockedChardetDetect.mockImplementation(() => {
                throw new Error('chardet failed');
            });
            const buffer = Buffer.from('test');
            const result = getCachedEncodingForBuffer(buffer);
            expect(result).toBe('utf-8');
        });
        it('should not cache buffer detection results', () => {
            // System encoding fails initially
            mockedExecSync.mockImplementation(() => {
                throw new Error('locale command failed');
            });
            const buffer1 = Buffer.from('test1');
            const buffer2 = Buffer.from('test2');
            mockedChardetDetect
                .mockReturnValueOnce('ISO-8859-1')
                .mockReturnValueOnce('UTF-16');
            const result1 = getCachedEncodingForBuffer(buffer1);
            const result2 = getCachedEncodingForBuffer(buffer2);
            expect(result1).toBe('iso-8859-1');
            expect(result2).toBe('utf-16');
            expect(mockedChardetDetect).toHaveBeenCalledTimes(2);
        });
        it('should handle Windows system encoding', () => {
            mockedOsPlatform.mockReturnValue('win32');
            mockedExecSync.mockReturnValue('Active code page: 1252');
            const buffer = Buffer.from('test');
            const result = getCachedEncodingForBuffer(buffer);
            expect(result).toBe('windows-1252');
        });
        it('should cache null system encoding result', () => {
            // Reset the cache specifically for this test
            resetEncodingCache();
            // Ensure we're on Unix-like for this test
            mockedOsPlatform.mockReturnValue('linux');
            // System encoding detection returns null
            mockedExecSync.mockImplementation(() => {
                throw new Error('locale command failed');
            });
            const buffer1 = Buffer.from('test1');
            const buffer2 = Buffer.from('test2');
            mockedChardetDetect
                .mockReturnValueOnce('ISO-8859-1')
                .mockReturnValueOnce('UTF-16');
            // Clear any previous calls from beforeEach setup or previous tests
            mockedExecSync.mockClear();
            const result1 = getCachedEncodingForBuffer(buffer1);
            const result2 = getCachedEncodingForBuffer(buffer2);
            // Should call execSync only once due to caching (null result is cached)
            expect(mockedExecSync).toHaveBeenCalledTimes(1);
            expect(result1).toBe('iso-8859-1');
            expect(result2).toBe('utf-16');
            // Call a third time to verify cache is still used
            const buffer3 = Buffer.from('test3');
            mockedChardetDetect.mockReturnValueOnce('UTF-32');
            const result3 = getCachedEncodingForBuffer(buffer3);
            // Still should be only one call to execSync
            expect(mockedExecSync).toHaveBeenCalledTimes(1);
            expect(result3).toBe('utf-32');
        });
    });
    describe('Cross-platform behavior', () => {
        it('should work correctly on macOS', () => {
            mockedOsPlatform.mockReturnValue('darwin');
            process.env['LANG'] = 'en_US.UTF-8';
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
        });
        it('should work correctly on other Unix-like systems', () => {
            mockedOsPlatform.mockReturnValue('freebsd');
            process.env['LANG'] = 'en_US.UTF-8';
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
        });
        it('should handle unknown platforms as Unix-like', () => {
            mockedOsPlatform.mockReturnValue('unknown');
            process.env['LANG'] = 'en_US.UTF-8';
            const result = getSystemEncoding();
            expect(result).toBe('utf-8');
        });
    });
    describe('Edge cases and error handling', () => {
        it('should handle empty buffer gracefully', () => {
            mockedOsPlatform.mockReturnValue('linux');
            process.env['LANG'] = 'en_US.UTF-8';
            const buffer = Buffer.alloc(0);
            const result = getCachedEncodingForBuffer(buffer);
            expect(result).toBe('utf-8');
        });
        it('should handle very large buffers', () => {
            mockedOsPlatform.mockReturnValue('linux');
            process.env['LANG'] = 'en_US.UTF-8';
            const buffer = Buffer.alloc(1024 * 1024, 'a');
            const result = getCachedEncodingForBuffer(buffer);
            expect(result).toBe('utf-8');
        });
        it('should handle Unicode content', () => {
            mockedOsPlatform.mockReturnValue('linux');
            const unicodeText = '你好世界 🌍 ñoño';
            // System encoding fails
            mockedExecSync.mockImplementation(() => {
                throw new Error('locale command failed');
            });
            mockedChardetDetect.mockReturnValue('UTF-8');
            const buffer = Buffer.from(unicodeText, 'utf8');
            const result = getCachedEncodingForBuffer(buffer);
            expect(result).toBe('utf-8');
        });
    });
});
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