# frozen_string_literal: true

require 'yaml'

module Diffend
  # Module for all the components related to setting up the config
  module Config
    # Class responsible for fetching the config from .diffend.yml
    module Fetcher
      # All the errors for missing keys in the configuration file
      MISSING_KEY_ERRORS = [
        Errors::ProjectIdMissingInConfigurationFile,
        Errors::ShareableIdMissingInConfigurationFile,
        Errors::ShareableKeyMissingInConfigurationFile,
        Errors::BuildPathMissingInConfigurationFile
      ].freeze

      class << self
        # @param build_path [String] path of the current build
        #
        # @return [OpenStruct] open struct with config details
        #
        # @example
        #   details = Fetcher.new.call('./')
        #   details.build_path #=> './'
        def call(build_path)
          build(build_path)
        rescue Errors::MissingConfigurationFile
          Bundler.ui.error(build_missing_error_message(build_path))

          raise Diffend::Errors::HandledException
        rescue Errors::EmptyConfigurationFile
          Bundler.ui.error(build_empty_error_message(build_path))

          raise Diffend::Errors::HandledException
        rescue Errors::MalformedConfigurationFile
          Bundler.ui.error(build_malformed_error_message(build_path))

          raise Diffend::Errors::HandledException
        rescue *MISSING_KEY_ERRORS => e
          Bundler.ui.error(build_missing_key_error_message(e))

          raise Diffend::Errors::HandledException
        end

        private

        # @param build_path [String] path of the current build
        #
        # @return [OpenStruct] open struct with config details
        def build(build_path)
          content = ERB.new(
            File.read(
              FileFinder.call(build_path)
            )
          ).result

          raise Errors::EmptyConfigurationFile if content.empty?

          OpenStruct.new(
            parse_file(content)
              .merge(build_path: build_path)
              .merge(diffend_env: ENV['DIFFEND_ENV'] || 'development')
          )
          .tap(&Validator.method(:call))
        end

        def parse_file(content)
          YAML.safe_load(content)
        rescue Psych::SyntaxError
          raise Errors::MalformedConfigurationFile
        end

        # @param build_path [String] path of the current build
        #
        # @return [String] missing configuration file message
        def build_missing_error_message(build_path)
          <<~MSG
            \nWe were unable to locate Diffend configuration file.\n
            Please make sure that .diffend.yml is present in #{build_path} folder.\n
          MSG
        end

        # @return [String] empty configuration file message
        def build_empty_error_message
          <<~MSG
            \nYour Diffend configuration file is empty.\n
            Please re-setup.\n
          MSG
        end

        # @return [String] malformed configuration file message
        def build_malformed_error_message
          <<~MSG
            \nYour Diffend configuration file is malformed.\n
            Please re-setup.\n
          MSG
        end

        # @return [String] malformed configuration file message
        def build_missing_key_error_message(exception)
          missing_key = missing_key_from_exception(exception)

          <<~MSG
            \nYour Diffend configuration file is missing #{missing_key} key.\n
            Please re-setup.\n
          MSG
        end

        def missing_key_from_exception(exception)
          case exception
          when Errors::ProjectIdMissingInConfigurationFile then 'project_id'
          when Errors::ShareableIdMissingInConfigurationFile then 'shareable_id'
          when Errors::ShareableKeyMissingInConfigurationFile then 'shareable_key'
          when Errors::BuildPathMissingInConfigurationFile then 'build_path'
          end
        end
      end
    end
  end
end