import { MercurePublishError } from './errors/publish_error.js'
import { MercureTimeoutError } from './errors/timeout_error.js'
import type { MercureConfig, SendOptions } from './types/main.js'

const DEFAULT_TIMEOUT = 5000

export class Publisher {
  #config: MercureConfig

  constructor(config: MercureConfig) {
    this.#config = config
  }

  async publish(
    topics: string | string[],
    data: Record<string, unknown> = {},
    options: SendOptions = {}
  ): Promise<Response> {
    const topicList = Array.isArray(topics) ? topics : [topics]
    const form = new URLSearchParams()

    for (const topic of topicList) {
      form.append('topic', topic)
    }
    form.append('data', JSON.stringify(data))

    if (options.private) form.append('private', 'on')
    if (options.id) form.append('id', options.id)
    if (options.type) form.append('type', options.type)
    if (options.retry !== undefined) form.append('retry', String(options.retry))

    const timeout = this.#config.http?.timeout ?? DEFAULT_TIMEOUT
    const controller = timeout > 0 ? new AbortController() : null
    const timer = controller ? setTimeout(() => controller.abort(), timeout) : null

    try {
      const response = await fetch(this.#config.endpoint, {
        method: 'POST',
        headers: {
          'Authorization': `Bearer ${this.#config.adminToken}`,
          'Content-Type': 'application/x-www-form-urlencoded',
        },
        body: form.toString(),
        signal: controller?.signal,
      })

      if (!response.ok) {
        const body = await response.text()
        throw new MercurePublishError(response.status, body)
      }

      return response
    } catch (err) {
      if ((err as Error)?.name === 'AbortError') {
        throw new MercureTimeoutError(timeout)
      }
      throw err
    } finally {
      if (timer) clearTimeout(timer)
    }
  }
}