import * as fs from 'node:fs';
import { execFile } from 'node:child_process';
import { promisify } from 'node:util';
import { Action, type IActionConfig, type IActionContext } from './base-action.ts';
import { logger } from '../logger.ts';

const execFileAsync = promisify(execFile);

/**
 * ShutdownAction - Initiates system shutdown
 *
 * This action triggers a system shutdown using the standard shutdown command.
 * It includes a configurable delay to allow VMs and services to gracefully terminate.
 */
export class ShutdownAction extends Action {
  readonly type = 'shutdown';

  /**
   * Execute the shutdown action
   * @param context Action context with UPS state
   */
  async execute(context: IActionContext): Promise<void> {
    // Check if we should execute based on trigger mode and thresholds
    if (!this.shouldExecute(context)) {
      logger.info(`Shutdown action skipped (trigger mode: ${this.config.triggerMode || 'powerChangesAndThresholds'})`);
      return;
    }

    const shutdownDelay = this.config.shutdownDelay || 5; // Default 5 minutes

    logger.log('');
    logger.logBoxTitle('Initiating System Shutdown', 60, 'error');
    logger.logBoxLine(`UPS: ${context.upsName} (${context.upsId})`);
    logger.logBoxLine(`Power Status: ${context.powerStatus}`);
    logger.logBoxLine(`Battery: ${context.batteryCapacity}%`);
    logger.logBoxLine(`Runtime: ${context.batteryRuntime} minutes`);
    logger.logBoxLine(`Trigger: ${context.triggerReason}`);
    logger.logBoxLine(`Shutdown delay: ${shutdownDelay} minutes`);
    logger.logBoxEnd();
    logger.log('');

    try {
      await this.executeShutdownCommand(shutdownDelay);
    } catch (error) {
      logger.error(
        `Shutdown command failed: ${error instanceof Error ? error.message : String(error)}`,
      );
      // Try alternative methods
      await this.tryAlternativeShutdownMethods();
    }
  }

  /**
   * Execute the primary shutdown command
   * @param delayMinutes Minutes to delay before shutdown
   */
  private async executeShutdownCommand(delayMinutes: number): Promise<void> {
    // Find shutdown command in common system paths
    const shutdownPaths = [
      '/sbin/shutdown',
      '/usr/sbin/shutdown',
      '/bin/shutdown',
      '/usr/bin/shutdown',
    ];

    let shutdownCmd = '';
    for (const path of shutdownPaths) {
      try {
        if (fs.existsSync(path)) {
          shutdownCmd = path;
          logger.log(`Found shutdown command at: ${shutdownCmd}`);
          break;
        }
      } catch (_e) {
        // Continue checking other paths
      }
    }

    if (shutdownCmd) {
      // Execute shutdown command with delay to allow for VM graceful shutdown
      const message = `UPS battery critical, shutting down in ${delayMinutes} minutes`;
      logger.log(`Executing: ${shutdownCmd} -h +${delayMinutes} "${message}"`);

      const { stdout } = await execFileAsync(shutdownCmd, [
        '-h',
        `+${delayMinutes}`,
        message,
      ]);

      logger.log(`Shutdown initiated: ${stdout}`);
      logger.log(`Allowing ${delayMinutes} minutes for VMs to shut down safely`);
    } else {
      throw new Error('Shutdown command not found in common paths');
    }
  }

  /**
   * Try alternative shutdown methods if primary command fails
   */
  private async tryAlternativeShutdownMethods(): Promise<void> {
    logger.error('Trying alternative shutdown methods...');

    const alternatives = [
      { cmd: 'poweroff', args: ['--force'] },
      { cmd: 'halt', args: ['-p'] },
      { cmd: 'systemctl', args: ['poweroff'] },
      { cmd: 'reboot', args: ['-p'] }, // Some systems allow reboot -p for power off
    ];

    for (const alt of alternatives) {
      try {
        // First check if command exists in common system paths
        const paths = [
          `/sbin/${alt.cmd}`,
          `/usr/sbin/${alt.cmd}`,
          `/bin/${alt.cmd}`,
          `/usr/bin/${alt.cmd}`,
        ];

        let cmdPath = '';
        for (const path of paths) {
          if (fs.existsSync(path)) {
            cmdPath = path;
            break;
          }
        }

        if (cmdPath) {
          logger.log(`Trying alternative shutdown method: ${cmdPath} ${alt.args.join(' ')}`);
          await execFileAsync(cmdPath, alt.args);
          logger.log(`Alternative method ${alt.cmd} succeeded`);
          return; // Exit if successful
        }
      } catch (_altError) {
        logger.error(`Alternative method ${alt.cmd} failed`);
        // Continue to next method
      }
    }

    logger.error('All shutdown methods failed');
  }
}