import { exec } from 'child_process';
import { promisify } from 'util';
import * as path from 'path';
import * as fs from 'fs-extra';
import { DiagramFormat } from '../types/diagram-types.js';

const execAsync = promisify(exec);

// Functional types
type VSCodeConfig = Readonly<{
  workspaceRoot: string;
  extensionId: string;
}>;

type ExtensionStatus = Readonly<{
  isInstalled: boolean;
  isVSCodeAvailable: boolean;
  version?: string;
}>;

type SetupResult = Readonly<{
  success: boolean;
  message: string;
}>;

type FileExtensionMap = Readonly<Record<DiagramFormat, string>>;

type PlatformCommandMap = Readonly<Record<string, string>>;

// Pure function to create VSCode configuration
export const createVSCodeConfig = (workspaceRoot?: string): VSCodeConfig => ({
  workspaceRoot: workspaceRoot || process.cwd(),
  extensionId: 'hediet.vscode-drawio'
});

// Pure function to get file extension mapping
const getFileExtensionMap = (): FileExtensionMap => ({
  [DiagramFormat.DRAWIO]: 'drawio',
  [DiagramFormat.DRAWIO_SVG]: 'drawio.svg',
  [DiagramFormat.DRAWIO_PNG]: 'drawio.png',
  [DiagramFormat.DIO]: 'dio',
  [DiagramFormat.XML]: 'xml'
});

// Pure function to get file extension for diagram format
export const getFileExtension = (format: DiagramFormat): string => {
  const extensionMap = getFileExtensionMap();
  return extensionMap[format] || 'drawio';
};

// Pure function to get platform-specific file explorer commands
const getPlatformCommandMap = (targetPath: string): PlatformCommandMap => ({
  'win32': `explorer "${targetPath}"`,
  'darwin': `open "${targetPath}"`,
  'linux': `xdg-open "${targetPath}"`
});

// Pure function to get platform-specific file explorer command
const getFileExplorerCommand = (targetPath: string): string => {
  const platform = process.platform;
  const commandMap = getPlatformCommandMap(targetPath);
  
  const command = commandMap[platform];
  if (!command) {
    throw new Error(`Unsupported platform: ${platform}`);
  }

  return command;
};

// Higher-order function for command execution with error handling
const withCommandErrorHandling = <T extends any[], R>(
  operation: (...args: T) => Promise<R>
) => async (...args: T): Promise<R> => {
  try {
    return await operation(...args);
  } catch (error) {
    throw new Error(`Command execution failed: ${error}`);
  }
};

// Pure function to execute VSCode command
export const executeVSCodeCommand = withCommandErrorHandling(async (command: string, args?: readonly string[]): Promise<string> => {
  const fullCommand = args ? `${command} ${args.join(' ')}` : command;
  const { stdout } = await execAsync(fullCommand);
  return stdout;
});

// Curried function to open diagram file in VSCode
export const openDiagramInVSCode = (config: VSCodeConfig) => async (filePath: string): Promise<void> => {
  const absolutePath = path.isAbsolute(filePath) 
    ? filePath 
    : path.resolve(config.workspaceRoot, filePath);
  
  await executeVSCodeCommand('code', [absolutePath]);
};

// Curried function to check if draw.io extension is installed
export const isDrawioExtensionInstalled = (config: VSCodeConfig) => async (): Promise<boolean> => {
  try {
    const stdout = await executeVSCodeCommand('code', ['--list-extensions']);
    return stdout.includes(config.extensionId);
  } catch (error) {
    console.warn('Could not check VSCode extensions:', error);
    return false;
  }
};

// Curried function to install draw.io extension
export const installDrawioExtension = (config: VSCodeConfig) => async (): Promise<void> => {
  await executeVSCodeCommand('code', ['--install-extension', config.extensionId]);
};

// Curried function to open VSCode workspace
export const openWorkspace = (config: VSCodeConfig) => async (): Promise<void> => {
  await executeVSCodeCommand('code', [config.workspaceRoot]);
};

// Pure function to check if VSCode is available
export const isVSCodeAvailable = async (): Promise<boolean> => {
  try {
    await executeVSCodeCommand('code', ['--version']);
    return true;
  } catch (error) {
    return false;
  }
};

// Pure function to get VSCode version
export const getVSCodeVersion = async (): Promise<string> => {
  const stdout = await executeVSCodeCommand('code', ['--version']);
  return stdout.split('\n')[0];
};

// Curried function to create and open new diagram in VSCode
export const createAndOpenDiagram = (config: VSCodeConfig) => 
  (fileName: string) => 
  (content: string) => 
  (format: DiagramFormat) => 
  async (outputDir?: string): Promise<string> => {
    const dir = outputDir || config.workspaceRoot;
    const extension = getFileExtension(format);
    const fullFileName = fileName.endsWith(extension) ? fileName : `${fileName}.${extension}`;
    const filePath = path.join(dir, fullFileName);

    // Write file
    await fs.ensureDir(path.dirname(filePath));
    await fs.writeFile(filePath, content, 'utf8');

    // Open in VSCode
    await openDiagramInVSCode(config)(filePath);

    return filePath;
  };

// Curried function to get workspace folders
export const getWorkspaceFolders = (config: VSCodeConfig) => async (): Promise<readonly string[]> => {
  try {
    // This would require VSCode API integration
    // For now, return current workspace
    return [config.workspaceRoot];
  } catch (error) {
    console.warn('Could not get workspace folders:', error);
    return [config.workspaceRoot];
  }
};

// Pure function to show notification (placeholder for VSCode API)
export const showNotification = async (
  message: string, 
  type: 'info' | 'warning' | 'error' = 'info'
): Promise<void> => {
  try {
    // This would require VSCode extension API
    // For now, just log to console
    console.log(`[${type.toUpperCase()}] ${message}`);
  } catch (error) {
    console.warn('Could not show notification:', error);
  }
};

// Curried function to open file explorer at specific path
export const openFileExplorer = (config: VSCodeConfig) => async (dirPath?: string): Promise<void> => {
  const targetPath = dirPath || config.workspaceRoot;
  const command = getFileExplorerCommand(targetPath);
  await executeVSCodeCommand(command);
};

// Pure function to refresh workspace (placeholder for VSCode API)
export const refreshWorkspace = async (): Promise<void> => {
  try {
    // This would require VSCode API integration
    // For now, just log
    console.log('Workspace refresh requested');
  } catch (error) {
    console.warn('Could not refresh workspace:', error);
  }
};

// Curried function to check VSCode extension status
export const checkExtensionStatus = (config: VSCodeConfig) => async (): Promise<ExtensionStatus> => {
  const isVSCodeAvail = await isVSCodeAvailable();
  
  if (!isVSCodeAvail) {
    return {
      isInstalled: false,
      isVSCodeAvailable: false
    };
  }

  const isInstalled = await isDrawioExtensionInstalled(config)();
  const version = isVSCodeAvail ? await getVSCodeVersion() : undefined;

  return {
    isInstalled,
    isVSCodeAvailable: isVSCodeAvail,
    version
  };
};

// Curried function to setup VSCode environment for draw.io
export const setupVSCodeEnvironment = (config: VSCodeConfig) => async (): Promise<SetupResult> => {
  try {
    const status = await checkExtensionStatus(config)();
    
    if (!status.isVSCodeAvailable) {
      return {
        success: false,
        message: 'VSCode is not available. Please install VSCode first.'
      };
    }

    if (!status.isInstalled) {
      await installDrawioExtension(config)();
      return {
        success: true,
        message: 'Draw.io extension installed successfully.'
      };
    }

    return {
      success: true,
      message: 'VSCode environment is ready for draw.io.'
    };
  } catch (error) {
    return {
      success: false,
      message: `Failed to setup VSCode environment: ${error}`
    };
  }
};

// Curried function to open multiple diagrams in VSCode
export const openMultipleDiagrams = (config: VSCodeConfig) => async (filePaths: readonly string[]): Promise<readonly string[]> => {
  const results: string[] = [];
  const openDiagram = openDiagramInVSCode(config);
  
  for (const filePath of filePaths) {
    try {
      await openDiagram(filePath);
      results.push(`Successfully opened: ${filePath}`);
    } catch (error) {
      results.push(`Failed to open ${filePath}: ${error}`);
    }
  }

  return results;
};

// Pure function to create VSCode workspace configuration for draw.io
export const createWorkspaceConfig = (config: VSCodeConfig): Readonly<Record<string, any>> => ({
  'hediet.vscode-drawio': {
    'local-storage': path.join(config.workspaceRoot, '.vscode', 'drawio-storage'),
    'theme': 'automatic',
    'online-url': 'https://embed.diagrams.net/',
    'offline': false
  }
});

// Curried function to save VSCode workspace settings
export const saveWorkspaceSettings = (config: VSCodeConfig) => async (settings: Readonly<Record<string, any>>): Promise<void> => {
  const settingsPath = path.join(config.workspaceRoot, '.vscode', 'settings.json');
  
  try {
    await fs.ensureDir(path.dirname(settingsPath));
    
    let existingSettings = {};
    if (await fs.pathExists(settingsPath)) {
      const content = await fs.readFile(settingsPath, 'utf8');
      existingSettings = JSON.parse(content);
    }

    const mergedSettings = { ...existingSettings, ...settings };
    await fs.writeFile(settingsPath, JSON.stringify(mergedSettings, null, 2), 'utf8');
  } catch (error) {
    throw new Error(`Failed to save workspace settings: ${error}`);
  }
};

// Utility functions for functional composition
export const pipe = <T>(...fns: Array<(arg: T) => T>) => (value: T): T =>
  fns.reduce((acc, fn) => fn(acc), value);

export const compose = <T>(...fns: Array<(arg: T) => T>) => (value: T): T =>
  fns.reduceRight((acc, fn) => fn(acc), value);

// Higher-order function for operations with retry logic
export const withRetry = <T extends any[], R>(
  operation: (...args: T) => Promise<R>,
  maxRetries: number = 3,
  delay: number = 1000
) => async (...args: T): Promise<R> => {
  let lastError: Error;
  
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      return await operation(...args);
    } catch (error) {
      lastError = error as Error;
      if (attempt === maxRetries) break;
      
      await new Promise(resolve => setTimeout(resolve, delay * attempt));
    }
  }
  
  throw lastError!;
};

// Higher-order function for operations with timeout
export const withTimeout = <T extends any[], R>(
  operation: (...args: T) => Promise<R>,
  timeoutMs: number = 30000
) => async (...args: T): Promise<R> => {
  return Promise.race([
    operation(...args),
    new Promise<never>((_, reject) => 
      setTimeout(() => reject(new Error(`Operation timed out after ${timeoutMs}ms`)), timeoutMs)
    )
  ]);
};

// Functional VSCode operations with retry and timeout
export const openDiagramInVSCodeWithRetry = (config: VSCodeConfig) => 
  withRetry(openDiagramInVSCode(config));

export const setupVSCodeEnvironmentWithTimeout = (config: VSCodeConfig) => 
  withTimeout(setupVSCodeEnvironment(config));

// Pure function to validate VSCode configuration
export const validateVSCodeConfig = (config: VSCodeConfig): boolean => {
  return typeof config.workspaceRoot === 'string' && 
         config.workspaceRoot.length > 0 &&
         typeof config.extensionId === 'string' &&
         config.extensionId.length > 0;
};

// Pure function to create validated VSCode configuration
export const createValidatedVSCodeConfig = (workspaceRoot?: string): VSCodeConfig => {
  const config = createVSCodeConfig(workspaceRoot);
  
  if (!validateVSCodeConfig(config)) {
    throw new Error('Invalid VSCode configuration');
  }
  
  return config;
};