/**
 * tools/utils.js
 * Utility functions for Task Master CLI integration
 */

import { spawnSync } from 'child_process';
import path from 'path';
import { contextManager } from '../core/context-manager.js'; // Import the singleton

/**
 * Get normalized project root path
 * @param {string|undefined} projectRootRaw - Raw project root from arguments
 * @param {Object} log - Logger object
 * @returns {string} - Normalized absolute path to project root
 */
export function getProjectRoot(projectRootRaw, log) {
	// Make sure projectRoot is set
	const rootPath = projectRootRaw || process.cwd();

	// Ensure projectRoot is absolute
	const projectRoot = path.isAbsolute(rootPath)
		? rootPath
		: path.resolve(process.cwd(), rootPath);

	log.info(`Using project root: ${projectRoot}`);
	return projectRoot;
}

/**
 * Handle API result with standardized error handling and response formatting
 * @param {Object} result - Result object from API call with success, data, and error properties
 * @param {Object} log - Logger object
 * @param {string} errorPrefix - Prefix for error messages
 * @param {Function} processFunction - Optional function to process successful result data
 * @returns {Object} - Standardized MCP response object
 */
export function handleApiResult(
	result,
	log,
	errorPrefix = 'API error',
	processFunction = processMCPResponseData
) {
	if (!result.success) {
		const errorMsg = result.error?.message || `Unknown ${errorPrefix}`;
		// Include cache status in error logs
		log.error(`${errorPrefix}: ${errorMsg}. From cache: ${result.fromCache}`); // Keep logging cache status on error
		return createErrorResponse(errorMsg);
	}

	// Process the result data if needed
	const processedData = processFunction
		? processFunction(result.data)
		: result.data;

	// Log success including cache status
	log.info(`Successfully completed operation. From cache: ${result.fromCache}`); // Add success log with cache status

	// Create the response payload including the fromCache flag
	const responsePayload = {
		fromCache: result.fromCache, // Get the flag from the original 'result'
		data: processedData // Nest the processed data under a 'data' key
	};

	// Pass this combined payload to createContentResponse
	return createContentResponse(responsePayload);
}

/**
 * Execute a Task Master CLI command using child_process
 * @param {string} command - The command to execute
 * @param {Object} log - The logger object from FastMCP
 * @param {Array} args - Arguments for the command
 * @param {string|undefined} projectRootRaw - Optional raw project root path (will be normalized internally)
 * @returns {Object} - The result of the command execution
 */
export function executeTaskMasterCommand(
	command,
	log,
	args = [],
	projectRootRaw = null
) {
	try {
		// Normalize project root internally using the getProjectRoot utility
		const cwd = getProjectRoot(projectRootRaw, log);

		log.info(
			`Executing task-master ${command} with args: ${JSON.stringify(
				args
			)} in directory: ${cwd}`
		);

		// Prepare full arguments array
		const fullArgs = [command, ...args];

		// Common options for spawn
		const spawnOptions = {
			encoding: 'utf8',
			cwd: cwd
		};

		// Execute the command using the global task-master CLI or local script
		// Try the global CLI first
		let result = spawnSync('task-master', fullArgs, spawnOptions);

		// If global CLI is not available, try fallback to the local script
		if (result.error && result.error.code === 'ENOENT') {
			log.info('Global task-master not found, falling back to local script');
			result = spawnSync('node', ['scripts/dev.js', ...fullArgs], spawnOptions);
		}

		if (result.error) {
			throw new Error(`Command execution error: ${result.error.message}`);
		}

		if (result.status !== 0) {
			// Improve error handling by combining stderr and stdout if stderr is empty
			const errorOutput = result.stderr
				? result.stderr.trim()
				: result.stdout
					? result.stdout.trim()
					: 'Unknown error';
			throw new Error(
				`Command failed with exit code ${result.status}: ${errorOutput}`
			);
		}

		return {
			success: true,
			stdout: result.stdout,
			stderr: result.stderr
		};
	} catch (error) {
		log.error(`Error executing task-master command: ${error.message}`);
		return {
			success: false,
			error: error.message
		};
	}
}

/**
 * Checks cache for a result using the provided key. If not found, executes the action function,
 * caches the result upon success, and returns the result.
 *
 * @param {Object} options - Configuration options.
 * @param {string} options.cacheKey - The unique key for caching this operation's result.
 * @param {Function} options.actionFn - The async function to execute if the cache misses.
 *                                      Should return an object like { success: boolean, data?: any, error?: { code: string, message: string } }.
 * @param {Object} options.log - The logger instance.
 * @returns {Promise<Object>} - An object containing the result, indicating if it was from cache.
 *                              Format: { success: boolean, data?: any, error?: { code: string, message: string }, fromCache: boolean }
 */
export async function getCachedOrExecute({ cacheKey, actionFn, log }) {
	// Check cache first
	const cachedResult = contextManager.getCachedData(cacheKey);

	if (cachedResult !== undefined) {
		log.info(`Cache hit for key: ${cacheKey}`);
		// Return the cached data in the same structure as a fresh result
		return {
			...cachedResult, // Spread the cached result to maintain its structure
			fromCache: true // Just add the fromCache flag
		};
	}

	log.info(`Cache miss for key: ${cacheKey}. Executing action function.`);

	// Execute the action function if cache missed
	const result = await actionFn();

	// If the action was successful, cache the result (but without fromCache flag)
	if (result.success && result.data !== undefined) {
		log.info(`Action successful. Caching result for key: ${cacheKey}`);
		// Cache the entire result structure (minus the fromCache flag)
		const { fromCache, ...resultToCache } = result;
		contextManager.setCachedData(cacheKey, resultToCache);
	} else if (!result.success) {
		log.warn(
			`Action failed for cache key ${cacheKey}. Result not cached. Error: ${result.error?.message}`
		);
	} else {
		log.warn(
			`Action for cache key ${cacheKey} succeeded but returned no data. Result not cached.`
		);
	}

	// Return the fresh result, indicating it wasn't from cache
	return {
		...result,
		fromCache: false
	};
}

/**
 * Executes a Task Master tool action with standardized error handling, logging, and response formatting.
 * Integrates caching logic via getCachedOrExecute if a cacheKeyGenerator is provided.
 *
 * @param {Object} options - Options for executing the tool action
 * @param {Function} options.actionFn - The core action function (e.g., listTasksDirect) to execute. Should return {success, data, error}.
 * @param {Object} options.args - Arguments for the action, passed to actionFn and cacheKeyGenerator.
 * @param {Object} options.log - Logger object from FastMCP.
 * @param {string} options.actionName - Name of the action for logging purposes.
 * @param {Function} [options.cacheKeyGenerator] - Optional function to generate a cache key based on args. If provided, caching is enabled.
 * @param {Function} [options.processResult=processMCPResponseData] - Optional function to process the result data before returning.
 * @returns {Promise<Object>} - Standardized response for FastMCP.
 */
export async function executeMCPToolAction({
	actionFn,
	args,
	log,
	actionName,
	cacheKeyGenerator, // Note: We decided not to use this for listTasks for now
	processResult = processMCPResponseData
}) {
	try {
		// Log the action start
		log.info(`${actionName} with args: ${JSON.stringify(args)}`);

		// Normalize project root path - common to almost all tools
		const projectRootRaw = args.projectRoot || process.cwd();
		const projectRoot = path.isAbsolute(projectRootRaw)
			? projectRootRaw
			: path.resolve(process.cwd(), projectRootRaw);

		log.info(`Using project root: ${projectRoot}`);
		const executionArgs = { ...args, projectRoot };

		let result;
		const cacheKey = cacheKeyGenerator
			? cacheKeyGenerator(executionArgs)
			: null;

		if (cacheKey) {
			// Use caching utility
			log.info(`Caching enabled for ${actionName} with key: ${cacheKey}`);
			const cacheWrappedAction = async () => await actionFn(executionArgs, log);
			result = await getCachedOrExecute({
				cacheKey,
				actionFn: cacheWrappedAction,
				log
			});
		} else {
			// Execute directly without caching
			log.info(`Caching disabled for ${actionName}. Executing directly.`);
			// We need to ensure the result from actionFn has a fromCache field
			// Let's assume actionFn now consistently returns { success, data/error, fromCache }
			// The current listTasksDirect does this if it calls getCachedOrExecute internally.
			result = await actionFn(executionArgs, log);
			// If the action function itself doesn't determine caching (like our original listTasksDirect refactor attempt),
			// we'd set it here:
			// result.fromCache = false;
		}

		// Handle error case
		if (!result.success) {
			const errorMsg =
				result.error?.message ||
				`Unknown error during ${actionName.toLowerCase()}`;
			// Include fromCache in error logs too, might be useful
			log.error(
				`Error during ${actionName.toLowerCase()}: ${errorMsg}. From cache: ${result.fromCache}`
			);
			return createErrorResponse(errorMsg);
		}

		// Log success
		log.info(
			`Successfully completed ${actionName.toLowerCase()}. From cache: ${result.fromCache}`
		);

		// Process the result data if needed
		const processedData = processResult
			? processResult(result.data)
			: result.data;

		// Create a new object that includes both the processed data and the fromCache flag
		const responsePayload = {
			fromCache: result.fromCache, // Include the flag here
			data: processedData // Embed the actual data under a 'data' key
		};

		// Pass this combined payload to createContentResponse
		return createContentResponse(responsePayload);
	} catch (error) {
		// Handle unexpected errors during the execution wrapper itself
		log.error(
			`Unexpected error during ${actionName.toLowerCase()} execution wrapper: ${error.message}`
		);
		console.error(error.stack); // Log stack for debugging wrapper errors
		return createErrorResponse(
			`Internal server error during ${actionName.toLowerCase()}: ${error.message}`
		);
	}
}

/**
 * Recursively removes specified fields from task objects, whether single or in an array.
 * Handles common data structures returned by task commands.
 * @param {Object|Array} taskOrData - A single task object or a data object containing a 'tasks' array.
 * @param {string[]} fieldsToRemove - An array of field names to remove.
 * @returns {Object|Array} - The processed data with specified fields removed.
 */
export function processMCPResponseData(
	taskOrData,
	fieldsToRemove = ['details', 'testStrategy']
) {
	if (!taskOrData) {
		return taskOrData;
	}

	// Helper function to process a single task object
	const processSingleTask = (task) => {
		if (typeof task !== 'object' || task === null) {
			return task;
		}

		const processedTask = { ...task };

		// Remove specified fields from the task
		fieldsToRemove.forEach((field) => {
			delete processedTask[field];
		});

		// Recursively process subtasks if they exist and are an array
		if (processedTask.subtasks && Array.isArray(processedTask.subtasks)) {
			// Use processArrayOfTasks to handle the subtasks array
			processedTask.subtasks = processArrayOfTasks(processedTask.subtasks);
		}

		return processedTask;
	};

	// Helper function to process an array of tasks
	const processArrayOfTasks = (tasks) => {
		return tasks.map(processSingleTask);
	};

	// Check if the input is a data structure containing a 'tasks' array (like from listTasks)
	if (
		typeof taskOrData === 'object' &&
		taskOrData !== null &&
		Array.isArray(taskOrData.tasks)
	) {
		return {
			...taskOrData, // Keep other potential fields like 'stats', 'filter'
			tasks: processArrayOfTasks(taskOrData.tasks)
		};
	}
	// Check if the input is likely a single task object (add more checks if needed)
	else if (
		typeof taskOrData === 'object' &&
		taskOrData !== null &&
		'id' in taskOrData &&
		'title' in taskOrData
	) {
		return processSingleTask(taskOrData);
	}
	// Check if the input is an array of tasks directly (less common but possible)
	else if (Array.isArray(taskOrData)) {
		return processArrayOfTasks(taskOrData);
	}

	// If it doesn't match known task structures, return it as is
	return taskOrData;
}

/**
 * Creates standard content response for tools
 * @param {string|Object} content - Content to include in response
 * @returns {Object} - Content response object in FastMCP format
 */
export function createContentResponse(content) {
	// FastMCP requires text type, so we format objects as JSON strings
	return {
		content: [
			{
				type: 'text',
				text:
					typeof content === 'object'
						? // Format JSON nicely with indentation
							JSON.stringify(content, null, 2)
						: // Keep other content types as-is
							String(content)
			}
		]
	};
}

/**
 * Creates error response for tools
 * @param {string} errorMessage - Error message to include in response
 * @returns {Object} - Error content response object in FastMCP format
 */
export function createErrorResponse(errorMessage) {
	return {
		content: [
			{
				type: 'text',
				text: `Error: ${errorMessage}`
			}
		],
		isError: true
	};
}