/**
 * Vultr API Client
 *
 * REST API 클라이언트 for Vultr cloud provider
 * - Instance management (create, get)
 * - Region listing
 * - Automatic retry with exponential backoff
 */

import type { Env, VultrInstance, VultrCreateRequest } from '../types';
import { createLogger } from '../utils/logger';
import { retryWithBackoff } from '../utils/retry';

const logger = createLogger('vultr-api');

/**
 * Vultr API Base URLs
 */
const DEFAULT_API_BASE = 'https://api.vultr.com/v2';

/**
 * Vultr Region
 */
export interface VultrRegion {
  id: string;
  city: string;
  country: string;
  continent: string;
  options: string[];
}

/**
 * Vultr API Error
 */
export class VultrAPIError extends Error {
  constructor(
    message: string,
    public readonly statusCode: number,
    public readonly response?: any
  ) {
    super(message);
    this.name = 'VultrAPIError';
  }
}

/**
 * Create a Vultr instance
 *
 * @param params - Instance creation parameters
 * @param env - Environment variables (API key, base URL)
 * @returns Created instance information
 * @throws VultrAPIError if API call fails
 */
export async function createInstance(
  params: VultrCreateRequest,
  env: Env
): Promise<VultrInstance> {
  const apiKey = env.VULTR_API_KEY;
  if (!apiKey) {
    throw new Error('VULTR_API_KEY is not configured');
  }

  const apiBase = env.VULTR_API_BASE || DEFAULT_API_BASE;
  const url = `${apiBase}/instances`;

  logger.info('Creating Vultr instance', {
    plan: params.plan,
    region: params.region,
    label: params.label,
  });

  return retryWithBackoff(
    async () => {
      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Authorization': `Bearer ${apiKey}`,
          'Content-Type': 'application/json',
        },
        body: JSON.stringify(params),
      });

      if (!response.ok) {
        const errorBody = await response.json().catch(() => ({}));
        logger.error('Vultr API create instance failed', undefined, {
          status: response.status,
          statusText: response.statusText,
          error: errorBody,
        });

        throw new VultrAPIError(
          `Vultr API error: ${response.status} ${response.statusText}`,
          response.status,
          errorBody
        );
      }

      const responseData = await response.json() as { instance: VultrInstance };
      const instance = responseData.instance;

      logger.info('Vultr instance created successfully', {
        id: instance.id,
        label: instance.label,
        main_ip: instance.main_ip,
      });

      return instance;
    },
    {
      maxRetries: 3,
      initialDelayMs: 1000,
      serviceName: 'vultr-api',
    }
  );
}

/**
 * Get a Vultr instance by ID
 *
 * @param instanceId - Vultr instance ID
 * @param env - Environment variables (API key, base URL)
 * @returns Instance information
 * @throws VultrAPIError if API call fails
 */
export async function getInstance(
  instanceId: string,
  env: Env
): Promise<VultrInstance> {
  const apiKey = env.VULTR_API_KEY;
  if (!apiKey) {
    throw new Error('VULTR_API_KEY is not configured');
  }

  const apiBase = env.VULTR_API_BASE || DEFAULT_API_BASE;
  const url = `${apiBase}/instances/${instanceId}`;

  logger.info('Getting Vultr instance', { instanceId });

  return retryWithBackoff(
    async () => {
      const response = await fetch(url, {
        method: 'GET',
        headers: {
          'Authorization': `Bearer ${apiKey}`,
        },
      });

      if (!response.ok) {
        const errorBody = await response.json().catch(() => ({}));
        logger.error('Vultr API get instance failed', undefined, {
          status: response.status,
          statusText: response.statusText,
          instanceId,
          error: errorBody,
        });

        throw new VultrAPIError(
          `Vultr API error: ${response.status} ${response.statusText}`,
          response.status,
          errorBody
        );
      }

      const responseData = await response.json() as { instance: VultrInstance };
      const instance = responseData.instance;

      logger.info('Vultr instance retrieved successfully', {
        id: instance.id,
        label: instance.label,
        status: instance.status,
      });

      return instance;
    },
    {
      maxRetries: 3,
      initialDelayMs: 1000,
      serviceName: 'vultr-api',
    }
  );
}

/**
 * Get list of available Vultr regions
 *
 * @param env - Environment variables (API key, base URL)
 * @returns Array of available regions
 * @throws VultrAPIError if API call fails
 */
export async function getRegions(env: Env): Promise<VultrRegion[]> {
  const apiKey = env.VULTR_API_KEY;
  if (!apiKey) {
    throw new Error('VULTR_API_KEY is not configured');
  }

  const apiBase = env.VULTR_API_BASE || DEFAULT_API_BASE;
  const url = `${apiBase}/regions`;

  logger.info('Getting Vultr regions');

  return retryWithBackoff(
    async () => {
      const response = await fetch(url, {
        method: 'GET',
        headers: {
          'Authorization': `Bearer ${apiKey}`,
        },
      });

      if (!response.ok) {
        const errorBody = await response.json().catch(() => ({}));
        logger.error('Vultr API get regions failed', undefined, {
          status: response.status,
          statusText: response.statusText,
          error: errorBody,
        });

        throw new VultrAPIError(
          `Vultr API error: ${response.status} ${response.statusText}`,
          response.status,
          errorBody
        );
      }

      const responseData = await response.json() as { regions: VultrRegion[] };
      const regions = responseData.regions;

      logger.info('Vultr regions retrieved successfully', {
        count: regions.length,
      });

      return regions;
    },
    {
      maxRetries: 3,
      initialDelayMs: 1000,
      serviceName: 'vultr-api',
    }
  );
}