import path from 'path';
import chalk from 'chalk';
import boxen from 'boxen';
import Table from 'cli-table3';
import { z } from 'zod';
import Fuse from 'fuse.js'; // Import Fuse.js for advanced fuzzy search

import {
	displayBanner,
	getStatusWithColor,
	startLoadingIndicator,
	stopLoadingIndicator,
	succeedLoadingIndicator,
	failLoadingIndicator,
	displayAiUsageSummary,
	displayContextAnalysis
} from '../ui.js';
import {
	readJSON,
	writeJSON,
	log as consoleLog,
	truncate,
	ensureTagMetadata,
	performCompleteTagMigration,
	markMigrationForNotice,
	getCurrentTag
} from '../utils.js';
import { generateObjectService } from '../ai-services-unified.js';
import { getDefaultPriority } from '../config-manager.js';
import generateTaskFiles from './generate-task-files.js';
import ContextGatherer from '../utils/contextGatherer.js';

// Define Zod schema for the expected AI output object
const AiTaskDataSchema = z.object({
	title: z.string().describe('Clear, concise title for the task'),
	description: z
		.string()
		.describe('A one or two sentence description of the task'),
	details: z
		.string()
		.describe('In-depth implementation details, considerations, and guidance'),
	testStrategy: z
		.string()
		.describe('Detailed approach for verifying task completion'),
	dependencies: z
		.array(z.number())
		.optional()
		.describe(
			'Array of task IDs that this task depends on (must be completed before this task can start)'
		)
});

/**
 * Get all tasks from all tags
 * @param {Object} rawData - The raw tagged data object
 * @returns {Array} A flat array of all task objects
 */
function getAllTasks(rawData) {
	let allTasks = [];
	for (const tagName in rawData) {
		if (
			Object.prototype.hasOwnProperty.call(rawData, tagName) &&
			rawData[tagName] &&
			Array.isArray(rawData[tagName].tasks)
		) {
			allTasks = allTasks.concat(rawData[tagName].tasks);
		}
	}
	return allTasks;
}

/**
 * Add a new task using AI
 * @param {string} tasksPath - Path to the tasks.json file
 * @param {string} prompt - Description of the task to add (required for AI-driven creation)
 * @param {Array} dependencies - Task dependencies
 * @param {string} priority - Task priority
 * @param {function} reportProgress - Function to report progress to MCP server (optional)
 * @param {Object} mcpLog - MCP logger object (optional)
 * @param {Object} session - Session object from MCP server (optional)
 * @param {string} outputFormat - Output format (text or json)
 * @param {Object} customEnv - Custom environment variables (optional) - Note: AI params override deprecated
 * @param {Object} manualTaskData - Manual task data (optional, for direct task creation without AI)
 * @param {boolean} useResearch - Whether to use the research model (passed to unified service)
 * @param {Object} context - Context object containing session and potentially projectRoot
 * @param {string} [context.projectRoot] - Project root path (for MCP/env fallback)
 * @param {string} [context.commandName] - The name of the command being executed (for telemetry)
 * @param {string} [context.outputType] - The output type ('cli' or 'mcp', for telemetry)
 * @param {string} [tag] - Tag for the task (optional)
 * @returns {Promise<object>} An object containing newTaskId and telemetryData
 */
async function addTask(
	tasksPath,
	prompt,
	dependencies = [],
	priority = null,
	context = {},
	outputFormat = 'text', // Default to text for CLI
	manualTaskData = null,
	useResearch = false,
	tag = null
) {
	const { session, mcpLog, projectRoot, commandName, outputType } = context;
	const isMCP = !!mcpLog;

	// Create a consistent logFn object regardless of context
	const logFn = isMCP
		? mcpLog // Use MCP logger if provided
		: {
				// Create a wrapper around consoleLog for CLI
				info: (...args) => consoleLog('info', ...args),
				warn: (...args) => consoleLog('warn', ...args),
				error: (...args) => consoleLog('error', ...args),
				debug: (...args) => consoleLog('debug', ...args),
				success: (...args) => consoleLog('success', ...args)
			};

	const effectivePriority = priority || getDefaultPriority(projectRoot);

	logFn.info(
		`Adding new task with prompt: "${prompt}", Priority: ${effectivePriority}, Dependencies: ${dependencies.join(', ') || 'None'}, Research: ${useResearch}, ProjectRoot: ${projectRoot}`
	);
	if (tag) {
		logFn.info(`Using tag context: ${tag}`);
	}

	let loadingIndicator = null;
	let aiServiceResponse = null; // To store the full response from AI service

	// Create custom reporter that checks for MCP log
	const report = (message, level = 'info') => {
		if (mcpLog) {
			mcpLog[level](message);
		} else if (outputFormat === 'text') {
			consoleLog(level, message);
		}
	};

	/**
	 * Recursively builds a dependency graph for a given task
	 * @param {Array} tasks - All tasks from tasks.json
	 * @param {number} taskId - ID of the task to analyze
	 * @param {Set} visited - Set of already visited task IDs
	 * @param {Map} depthMap - Map of task ID to its depth in the graph
	 * @param {number} depth - Current depth in the recursion
	 * @return {Object} Dependency graph data
	 */
	function buildDependencyGraph(
		tasks,
		taskId,
		visited = new Set(),
		depthMap = new Map(),
		depth = 0
	) {
		// Skip if we've already visited this task or it doesn't exist
		if (visited.has(taskId)) {
			return null;
		}

		// Find the task
		const task = tasks.find((t) => t.id === taskId);
		if (!task) {
			return null;
		}

		// Mark as visited
		visited.add(taskId);

		// Update depth if this is a deeper path to this task
		if (!depthMap.has(taskId) || depth < depthMap.get(taskId)) {
			depthMap.set(taskId, depth);
		}

		// Process dependencies
		const dependencyData = [];
		if (task.dependencies && task.dependencies.length > 0) {
			for (const depId of task.dependencies) {
				const depData = buildDependencyGraph(
					tasks,
					depId,
					visited,
					depthMap,
					depth + 1
				);
				if (depData) {
					dependencyData.push(depData);
				}
			}
		}

		return {
			id: task.id,
			title: task.title,
			description: task.description,
			status: task.status,
			dependencies: dependencyData
		};
	}

	try {
		// Read the existing tasks - IMPORTANT: Read the raw data without tag resolution
		let rawData = readJSON(tasksPath, projectRoot); // No tag parameter

		// Handle the case where readJSON returns resolved data with _rawTaggedData
		if (rawData && rawData._rawTaggedData) {
			// Use the raw tagged data and discard the resolved view
			rawData = rawData._rawTaggedData;
		}

		// If file doesn't exist or is invalid, create a new structure in memory
		if (!rawData) {
			report(
				'tasks.json not found or invalid. Initializing new structure.',
				'info'
			);
			rawData = {
				master: {
					tasks: [],
					metadata: {
						created: new Date().toISOString(),
						description: 'Default tasks context'
					}
				}
			};
			// Do not write the file here; it will be written later with the new task.
		}

		// Handle legacy format migration using utilities
		if (rawData && Array.isArray(rawData.tasks) && !rawData._rawTaggedData) {
			report('Legacy format detected. Migrating to tagged format...', 'info');

			// This is legacy format - migrate it to tagged format
			rawData = {
				master: {
					tasks: rawData.tasks,
					metadata: rawData.metadata || {
						created: new Date().toISOString(),
						updated: new Date().toISOString(),
						description: 'Tasks for master context'
					}
				}
			};
			// Ensure proper metadata using utility
			ensureTagMetadata(rawData.master, {
				description: 'Tasks for master context'
			});
			// Do not write the file here; it will be written later with the new task.

			// Perform complete migration (config.json, state.json)
			performCompleteTagMigration(tasksPath);
			markMigrationForNotice(tasksPath);

			report('Successfully migrated to tagged format.', 'success');
		}

		// Use the provided tag, or the current active tag, or default to 'master'
		const targetTag =
			tag || context.tag || getCurrentTag(projectRoot) || 'master';

		// Ensure the target tag exists
		if (!rawData[targetTag]) {
			report(
				`Tag "${targetTag}" does not exist. Please create it first using the 'add-tag' command.`,
				'error'
			);
			throw new Error(`Tag "${targetTag}" not found.`);
		}

		// Ensure the target tag has a tasks array and metadata object
		if (!rawData[targetTag].tasks) {
			rawData[targetTag].tasks = [];
		}
		if (!rawData[targetTag].metadata) {
			rawData[targetTag].metadata = {
				created: new Date().toISOString(),
				updated: new Date().toISOString(),
				description: ``
			};
		}

		// Get a flat list of ALL tasks across ALL tags to validate dependencies
		const allTasks = getAllTasks(rawData);

		// Find the highest task ID *within the target tag* to determine the next ID
		const tasksInTargetTag = rawData[targetTag].tasks;
		const highestId =
			tasksInTargetTag.length > 0
				? Math.max(...tasksInTargetTag.map((t) => t.id))
				: 0;
		const newTaskId = highestId + 1;

		// Only show UI box for CLI mode
		if (outputFormat === 'text') {
			console.log(
				boxen(chalk.white.bold(`Creating New Task #${newTaskId}`), {
					padding: 1,
					borderColor: 'blue',
					borderStyle: 'round',
					margin: { top: 1, bottom: 1 }
				})
			);
		}

		// Validate dependencies before proceeding
		const invalidDeps = dependencies.filter((depId) => {
			// Ensure depId is parsed as a number for comparison
			const numDepId = parseInt(depId, 10);
			return Number.isNaN(numDepId) || !allTasks.some((t) => t.id === numDepId);
		});

		if (invalidDeps.length > 0) {
			report(
				`The following dependencies do not exist or are invalid: ${invalidDeps.join(', ')}`,
				'warn'
			);
			report('Removing invalid dependencies...', 'info');
			dependencies = dependencies.filter(
				(depId) => !invalidDeps.includes(depId)
			);
		}
		// Ensure dependencies are numbers
		const numericDependencies = dependencies.map((dep) => parseInt(dep, 10));

		// Build dependency graphs for explicitly specified dependencies
		const dependencyGraphs = [];
		const allRelatedTaskIds = new Set();
		const depthMap = new Map();

		// First pass: build a complete dependency graph for each specified dependency
		for (const depId of numericDependencies) {
			const graph = buildDependencyGraph(allTasks, depId, new Set(), depthMap);
			if (graph) {
				dependencyGraphs.push(graph);
			}
		}

		// Second pass: build a set of all related task IDs for flat analysis
		for (const [taskId, depth] of depthMap.entries()) {
			allRelatedTaskIds.add(taskId);
		}

		let taskData;

		// Check if manual task data is provided
		if (manualTaskData) {
			report('Using manually provided task data', 'info');
			taskData = manualTaskData;
			report('DEBUG: Taking MANUAL task data path.', 'debug');

			// Basic validation for manual data
			if (
				!taskData.title ||
				typeof taskData.title !== 'string' ||
				!taskData.description ||
				typeof taskData.description !== 'string'
			) {
				throw new Error(
					'Manual task data must include at least a title and description.'
				);
			}
		} else {
			report('DEBUG: Taking AI task generation path.', 'debug');
			// --- Refactored AI Interaction ---
			report(`Generating task data with AI with prompt:\n${prompt}`, 'info');

			// --- Use the new ContextGatherer ---
			const contextGatherer = new ContextGatherer(projectRoot);
			const gatherResult = await contextGatherer.gather({
				semanticQuery: prompt,
				dependencyTasks: numericDependencies,
				format: 'research'
			});

			const gatheredContext = gatherResult.context;
			const analysisData = gatherResult.analysisData;

			// Display context analysis if not in silent mode
			if (outputFormat === 'text' && analysisData) {
				displayContextAnalysis(analysisData, prompt, gatheredContext.length);
			}

			// System Prompt - Enhanced for dependency awareness
			const systemPrompt =
				"You are a helpful assistant that creates well-structured tasks for a software development project. Generate a single new task based on the user's description, adhering strictly to the provided JSON schema. Pay special attention to dependencies between tasks, ensuring the new task correctly references any tasks it depends on.\n\n" +
				'When determining dependencies for a new task, follow these principles:\n' +
				'1. Select dependencies based on logical requirements - what must be completed before this task can begin.\n' +
				'2. Prioritize task dependencies that are semantically related to the functionality being built.\n' +
				'3. Consider both direct dependencies (immediately prerequisite) and indirect dependencies.\n' +
				'4. Avoid adding unnecessary dependencies - only include tasks that are genuinely prerequisite.\n' +
				'5. Consider the current status of tasks - prefer completed tasks as dependencies when possible.\n' +
				"6. Pay special attention to foundation tasks (1-5) but don't automatically include them without reason.\n" +
				'7. Recent tasks (higher ID numbers) may be more relevant for newer functionality.\n\n' +
				'The dependencies array should contain task IDs (numbers) of prerequisite tasks.\n';

			// Task Structure Description (for user prompt)
			const taskStructureDesc = `
      {
        "title": "Task title goes here",
        "description": "A concise one or two sentence description of what the task involves",
    "details": "Detailed implementation steps, considerations, code examples, or technical approach",
    "testStrategy": "Specific steps to verify correct implementation and functionality",
    "dependencies": [1, 3] // Example: IDs of tasks that must be completed before this task
  }
`;

			// Add any manually provided details to the prompt for context
			let contextFromArgs = '';
			if (manualTaskData?.title)
				contextFromArgs += `\n- Suggested Title: "${manualTaskData.title}"`;
			if (manualTaskData?.description)
				contextFromArgs += `\n- Suggested Description: "${manualTaskData.description}"`;
			if (manualTaskData?.details)
				contextFromArgs += `\n- Additional Details Context: "${manualTaskData.details}"`;
			if (manualTaskData?.testStrategy)
				contextFromArgs += `\n- Additional Test Strategy Context: "${manualTaskData.testStrategy}"`;

			// User Prompt
			const userPrompt = `You are generating the details for Task #${newTaskId}. Based on the user's request: "${prompt}", create a comprehensive new task for a software development project.
      
      ${gatheredContext}
      
      Based on the information about existing tasks provided above, include appropriate dependencies in the "dependencies" array. Only include task IDs that this new task directly depends on.
      
      Return your answer as a single JSON object matching the schema precisely:
      ${taskStructureDesc}
      
      Make sure the details and test strategy are comprehensive and specific. DO NOT include the task ID in the title.
      `;

			// Start the loading indicator - only for text mode
			if (outputFormat === 'text') {
				loadingIndicator = startLoadingIndicator(
					`Generating new task with ${useResearch ? 'Research' : 'Main'} AI... \n`
				);
			}

			try {
				const serviceRole = useResearch ? 'research' : 'main';
				report('DEBUG: Calling generateObjectService...', 'debug');

				aiServiceResponse = await generateObjectService({
					// Capture the full response
					role: serviceRole,
					session: session,
					projectRoot: projectRoot,
					schema: AiTaskDataSchema,
					objectName: 'newTaskData',
					systemPrompt: systemPrompt,
					prompt: userPrompt,
					commandName: commandName || 'add-task', // Use passed commandName or default
					outputType: outputType || (isMCP ? 'mcp' : 'cli') // Use passed outputType or derive
				});
				report('DEBUG: generateObjectService returned successfully.', 'debug');

				if (!aiServiceResponse || !aiServiceResponse.mainResult) {
					throw new Error(
						'AI service did not return the expected object structure.'
					);
				}

				// Prefer mainResult if it looks like a valid task object, otherwise try mainResult.object
				if (
					aiServiceResponse.mainResult.title &&
					aiServiceResponse.mainResult.description
				) {
					taskData = aiServiceResponse.mainResult;
				} else if (
					aiServiceResponse.mainResult.object &&
					aiServiceResponse.mainResult.object.title &&
					aiServiceResponse.mainResult.object.description
				) {
					taskData = aiServiceResponse.mainResult.object;
				} else {
					throw new Error('AI service did not return a valid task object.');
				}

				report('Successfully generated task data from AI.', 'success');

				// Success! Show checkmark
				if (loadingIndicator) {
					succeedLoadingIndicator(
						loadingIndicator,
						'Task generated successfully'
					);
					loadingIndicator = null; // Clear it
				}
			} catch (error) {
				// Failure! Show X
				if (loadingIndicator) {
					failLoadingIndicator(loadingIndicator, 'AI generation failed');
					loadingIndicator = null;
				}
				report(
					`DEBUG: generateObjectService caught error: ${error.message}`,
					'debug'
				);
				report(`Error generating task with AI: ${error.message}`, 'error');
				throw error; // Re-throw error after logging
			} finally {
				report('DEBUG: generateObjectService finally block reached.', 'debug');
				// Clean up if somehow still running
				if (loadingIndicator) {
					stopLoadingIndicator(loadingIndicator);
				}
			}
			// --- End Refactored AI Interaction ---
		}

		// Create the new task object
		const newTask = {
			id: newTaskId,
			title: taskData.title,
			description: taskData.description,
			details: taskData.details || '',
			testStrategy: taskData.testStrategy || '',
			status: 'pending',
			dependencies: taskData.dependencies?.length
				? taskData.dependencies
				: numericDependencies, // Use AI-suggested dependencies if available, fallback to manually specified
			priority: effectivePriority,
			subtasks: [] // Initialize with empty subtasks array
		};

		// Additional check: validate all dependencies in the AI response
		if (taskData.dependencies?.length) {
			const allValidDeps = taskData.dependencies.every((depId) => {
				const numDepId = parseInt(depId, 10);
				return (
					!Number.isNaN(numDepId) && allTasks.some((t) => t.id === numDepId)
				);
			});

			if (!allValidDeps) {
				report(
					'AI suggested invalid dependencies. Filtering them out...',
					'warn'
				);
				newTask.dependencies = taskData.dependencies.filter((depId) => {
					const numDepId = parseInt(depId, 10);
					return (
						!Number.isNaN(numDepId) && allTasks.some((t) => t.id === numDepId)
					);
				});
			}
		}

		// Add the task to the tasks array OF THE CORRECT TAG
		rawData[targetTag].tasks.push(newTask);
		// Update the tag's metadata
		ensureTagMetadata(rawData[targetTag], {
			description: `Tasks for ${targetTag} context`
		});

		report('DEBUG: Writing tasks.json...', 'debug');
		// Write the updated raw data back to the file
		// The writeJSON function will automatically filter out _rawTaggedData
		writeJSON(tasksPath, rawData);
		report('DEBUG: tasks.json written.', 'debug');

		// Generate markdown task files
		report('Generating task files...', 'info');
		report('DEBUG: Calling generateTaskFiles...', 'debug');
		// Pass mcpLog if available to generateTaskFiles
		await generateTaskFiles(tasksPath, path.dirname(tasksPath), {
			projectRoot,
			tag: targetTag
		});
		report('DEBUG: generateTaskFiles finished.', 'debug');

		// Show success message - only for text output (CLI)
		if (outputFormat === 'text') {
			const table = new Table({
				head: [
					chalk.cyan.bold('ID'),
					chalk.cyan.bold('Title'),
					chalk.cyan.bold('Description')
				],
				colWidths: [5, 30, 50] // Adjust widths as needed
			});

			table.push([
				newTask.id,
				truncate(newTask.title, 27),
				truncate(newTask.description, 47)
			]);

			console.log(chalk.green('✓ New task created successfully:'));
			console.log(table.toString());

			// Helper to get priority color
			const getPriorityColor = (p) => {
				switch (p?.toLowerCase()) {
					case 'high':
						return 'red';
					case 'low':
						return 'gray';
					default:
						return 'yellow';
				}
			};

			// Check if AI added new dependencies that weren't explicitly provided
			const aiAddedDeps = newTask.dependencies.filter(
				(dep) => !numericDependencies.includes(dep)
			);

			// Check if AI removed any dependencies that were explicitly provided
			const aiRemovedDeps = numericDependencies.filter(
				(dep) => !newTask.dependencies.includes(dep)
			);

			// Get task titles for dependencies to display
			const depTitles = {};
			newTask.dependencies.forEach((dep) => {
				const depTask = allTasks.find((t) => t.id === dep);
				if (depTask) {
					depTitles[dep] = truncate(depTask.title, 30);
				}
			});

			// Prepare dependency display string
			let dependencyDisplay = '';
			if (newTask.dependencies.length > 0) {
				dependencyDisplay = chalk.white('Dependencies:') + '\n';
				newTask.dependencies.forEach((dep) => {
					const isAiAdded = aiAddedDeps.includes(dep);
					const depType = isAiAdded ? chalk.yellow(' (AI suggested)') : '';
					dependencyDisplay +=
						chalk.white(
							`  - ${dep}: ${depTitles[dep] || 'Unknown task'}${depType}`
						) + '\n';
				});
			} else {
				dependencyDisplay = chalk.white('Dependencies: None') + '\n';
			}

			// Add info about removed dependencies if any
			if (aiRemovedDeps.length > 0) {
				dependencyDisplay +=
					chalk.gray('\nUser-specified dependencies that were not used:') +
					'\n';
				aiRemovedDeps.forEach((dep) => {
					const depTask = allTasks.find((t) => t.id === dep);
					const title = depTask ? truncate(depTask.title, 30) : 'Unknown task';
					dependencyDisplay += chalk.gray(`  - ${dep}: ${title}`) + '\n';
				});
			}

			// Add dependency analysis summary
			let dependencyAnalysis = '';
			if (aiAddedDeps.length > 0 || aiRemovedDeps.length > 0) {
				dependencyAnalysis =
					'\n' + chalk.white.bold('Dependency Analysis:') + '\n';
				if (aiAddedDeps.length > 0) {
					dependencyAnalysis +=
						chalk.green(
							`AI identified ${aiAddedDeps.length} additional dependencies`
						) + '\n';
				}
				if (aiRemovedDeps.length > 0) {
					dependencyAnalysis +=
						chalk.yellow(
							`AI excluded ${aiRemovedDeps.length} user-provided dependencies`
						) + '\n';
				}
			}

			// Show success message box
			console.log(
				boxen(
					chalk.white.bold(`Task ${newTaskId} Created Successfully`) +
						'\n\n' +
						chalk.white(`Title: ${newTask.title}`) +
						'\n' +
						chalk.white(`Status: ${getStatusWithColor(newTask.status)}`) +
						'\n' +
						chalk.white(
							`Priority: ${chalk[getPriorityColor(newTask.priority)](newTask.priority)}`
						) +
						'\n\n' +
						dependencyDisplay +
						dependencyAnalysis +
						'\n' +
						chalk.white.bold('Next Steps:') +
						'\n' +
						chalk.cyan(
							`1. Run ${chalk.yellow(`task-master show ${newTaskId}`)} to see complete task details`
						) +
						'\n' +
						chalk.cyan(
							`2. Run ${chalk.yellow(`task-master set-status --id=${newTaskId} --status=in-progress`)} to start working on it`
						) +
						'\n' +
						chalk.cyan(
							`3. Run ${chalk.yellow(`task-master expand --id=${newTaskId}`)} to break it down into subtasks`
						),
					{ padding: 1, borderColor: 'green', borderStyle: 'round' }
				)
			);

			// Display AI Usage Summary if telemetryData is available
			if (
				aiServiceResponse &&
				aiServiceResponse.telemetryData &&
				(outputType === 'cli' || outputType === 'text')
			) {
				displayAiUsageSummary(aiServiceResponse.telemetryData, 'cli');
			}
		}

		report(
			`DEBUG: Returning new task ID: ${newTaskId} and telemetry.`,
			'debug'
		);
		return {
			newTaskId: newTaskId,
			telemetryData: aiServiceResponse ? aiServiceResponse.telemetryData : null,
			tagInfo: aiServiceResponse ? aiServiceResponse.tagInfo : null
		};
	} catch (error) {
		// Stop any loading indicator on error
		if (loadingIndicator) {
			stopLoadingIndicator(loadingIndicator);
		}

		report(`Error adding task: ${error.message}`, 'error');
		if (outputFormat === 'text') {
			console.error(chalk.red(`Error: ${error.message}`));
		}
		// In MCP mode, we let the direct function handler catch and format
		throw error;
	}
}

export default addTask;