# frozen_string_literal: true

require 'faraday'
require 'faraday_middleware'

require_relative 'artifact'
require_relative 'build'
require_relative 'errors'

module CircleCIReporter
  # CircleCI API client
  class Client
    CIRCLECI_ENDPOINT = 'https://circleci.com/api/v1.1'

    # Fetch a build data from API and create a {Build} object for it.
    #
    # @param build_number [Integer, nil]
    # @return [Build, nil]
    # @raise [RequestError]
    # @see https://circleci.com/docs/api/v1-reference/#build
    def single_build(build_number)
      return unless build_number

      resp = get(single_build_url(build_number))
      body = JSON.parse(resp.body)
      raise RequestError.new(body['message'], resp) unless resp.success?

      create_build(body)
    end

    # Retrieve artifacts for the build.
    #
    # @param build_number [Integer]
    # @return [Array<Artifact>]
    # @raise [RequestError]
    # @see https://circleci.com/docs/api/v1-reference/#build-artifacts
    def artifacts(build_number)
      resp = get(artifacts_url(build_number))
      body = JSON.parse(resp.body)
      raise RequestError.new(body['message'], resp) unless resp.success?

      body.map{ |hash| create_artifact(hash) }
    end

    # Find the latest build number for the given vcs revision.
    #
    # @param revision [String]
    # @param branch [String, nil]
    # @return [Integer, nil]
    def build_number_by_revision(revision, branch: nil)
      build = recent_builds(branch).find { |recent_build| recent_build.match?(revision) }
      build ? build.build_number : nil
    end

    # Raw entry point for GET APIs.
    #
    # @param url [String]
    # @param params [Hash]
    # @return [Faraday::Response]
    def get(url, params = {})
      params['circle-token'] = configuration.circleci_token
      query_string = params.map { |key, value| "#{key}=#{value}" }.join('&')
      connection = Faraday.new do |faraday|
        faraday.use FaradayMiddleware::FollowRedirects
      end
      connection.get("#{url}?#{query_string}")
    end

    private

    # @return [Configuration]
    def configuration
      CircleCIReporter.configuration
    end

    # @param build_number [Integer]
    # @return [String] URL for "Artifacts of a Bulid API"
    def artifacts_url(build_number)
      [
        CIRCLECI_ENDPOINT,
        'project',
        configuration.vcs_type,
        configuration.project,
        build_number,
        'artifacts'
      ].join('/')
    end

    # @param branch [String, nil]
    # @return [Array<Build>]
    # @raise [RequestError]
    def recent_builds(branch)
      resp = get(recent_builds_url(branch), limit: 100)
      body = JSON.parse(resp.body)
      raise RequestError.new(body['message'], resp) unless resp.success?

      body.map { |hash| create_build(hash) }
    end

    # @param branch [String, nil]
    # @return [String]
    def recent_builds_url(branch)
      elements = [
        CIRCLECI_ENDPOINT,
        'project',
        configuration.vcs_type,
        configuration.project
      ]
      elements += ['tree', branch] if branch
      elements.join('/')
    end

    # @param build_number [Integer]
    # @return [String]
    def single_build_url(build_number)
      [
        CIRCLECI_ENDPOINT,
        'project',
        configuration.vcs_type,
        configuration.project,
        build_number
      ].join('/')
    end

    # @param hash [Hash]
    # @return [Artifact]
    def create_artifact(hash)
      Artifact.new(hash['path'], hash['url'], hash['node_index'])
    end

    # @param hash [Hash]
    # @return [Build]
    def create_build(hash)
      Build.new(hash['vcs_revision'], hash['build_num'])
    end
  end
end