/**
 * add_task tool
 * 
 * Agent tool to add a new task to a phase.
 * Auto-generates task_id from phase prefix ("phase1-task1", "phase1-task2", ...).
 * Sets status to "pending".
 * 
 * Used by: mission-pm skill
 */

import {
  readState,
  readRun,
  writeRun,
  findPhase,
  generateTaskId,
  createTask,
  addTaskToRun,
  ensureDir,
  getTaskDir
} from "../state.js";

export interface AddTaskParams {
  phase_id: string;
  name: string;
  file: string;
}

export interface AddTaskResult {
  success: boolean;
  message: string;
  taskId: string | null;
  errors: string[];
}

/**
 * Add a task to a phase in the active mission run
 * 
 * @param params.phase_id - ID of the phase to add task to (e.g., "phase1")
 * @param params.name - Human-readable task name (e.g., "Setup DB Schema")
 * @param params.file - Path to task contract file
 * @returns Result with generated task_id
 */
export function addTask(params: AddTaskParams): AddTaskResult {
  const result: AddTaskResult = {
    success: false,
    message: "",
    taskId: null,
    errors: []
  };

  try {
    // Validate parameters
    if (!params.phase_id || params.phase_id.trim() === "") {
      result.errors.push("Phase ID is required");
      result.message = "Failed to add task: phase_id is required";
      return result;
    }

    if (!params.name || params.name.trim() === "") {
      result.errors.push("Task name is required");
      result.message = "Failed to add task: name is required";
      return result;
    }

    if (!params.file || params.file.trim() === "") {
      result.errors.push("Task file is required");
      result.message = "Failed to add task: file is required";
      return result;
    }

    // Get active run
    const state = readState();
    if (!state.active_run_id) {
      result.errors.push("No active run");
      result.message = "Failed to add task: no active mission run";
      return result;
    }

    // Read run.json
    const run = readRun(state.active_run_id);
    if (!run) {
      result.errors.push(`Run not found: ${state.active_run_id}`);
      result.message = "Failed to add task: run not found";
      return result;
    }

    // Find phase
    const phase = findPhase(run, params.phase_id.trim());
    if (!phase) {
      result.errors.push(`Phase not found: ${params.phase_id}`);
      result.message = "Failed to add task: phase not found";
      return result;
    }

    // Generate task ID
    const taskId = generateTaskId(phase);

    // Create task
    const task = createTask(taskId, params.name.trim(), params.file.trim());

    // Add to run
    const updatedRun = addTaskToRun(run, params.phase_id.trim(), task);
    writeRun(updatedRun);

    // Create task directory
    const taskDir = getTaskDir(state.active_run_id, taskId);
    ensureDir(taskDir);

    result.success = true;
    result.taskId = taskId;
    result.message = `Task added: ${taskId} - ${params.name}`;

  } catch (error) {
    result.success = false;
    result.message = `Error adding task: ${error instanceof Error ? error.message : String(error)}`;
    result.errors.push(String(error));
  }

  return result;
}