/**
 * add_phase tool
 * 
 * Agent tool to add a new phase to the current mission run.
 * Auto-generates phase_id ("phase1", "phase2", ...).
 * Sets status to "pending".
 * 
 * Used by: mission-pm skill
 */

import {
  readState,
  readRun,
  writeRun,
  generatePhaseId,
  createPhase,
  addPhaseToRun
} from "../state.js";

export interface AddPhaseParams {
  name: string;
  file: string;
}

export interface AddPhaseResult {
  success: boolean;
  message: string;
  phaseId: string | null;
  errors: string[];
}

/**
 * Add a phase to the active mission run
 * 
 * @param params.name - Human-readable phase name (e.g., "Auth Backend")
 * @param params.file - Path to phase definition/reference file
 * @returns Result with generated phase_id
 */
export function addPhase(params: AddPhaseParams): AddPhaseResult {
  const result: AddPhaseResult = {
    success: false,
    message: "",
    phaseId: null,
    errors: []
  };

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

    if (!params.file || params.file.trim() === "") {
      result.errors.push("Phase file is required");
      result.message = "Failed to add phase: 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 phase: 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 phase: run not found";
      return result;
    }

    // Generate phase ID
    const phaseId = generatePhaseId(run);

    // Create phase
    const phase = createPhase(phaseId, params.name.trim(), params.file.trim());

    // Add to run
    const updatedRun = addPhaseToRun(run, phase);
    writeRun(updatedRun);

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

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

  return result;
}