class Envirobly::Config

def append_image_tags!
  @result[:services].each do |name, service|
    next if NON_BUILDABLE_TYPES.include?(service[:type]) || service[:image].present?
    checksums = []
    BUILD_DEFAULTS.each do |attribute, options|
      value = service.fetch(attribute, options.first)
      if @commit.public_send(options.second, value)
        checksums << @commit.objects_with_checksum_at(value)
      end
    end
    if checksums.size == 2
      @result[:services][name][:image_tag] = Digest::SHA1.hexdigest checksums.to_json
    end
  end
end

def compile(environment = nil)
  return unless @project
  @environment = environment
  @result = @project.slice(:services)
  set_project_url
  merge_environment_overrides! unless @environment.nil?
  transform_env_var_values!
  append_image_tags!
end

def dig(*args)
  @project.dig(*args)
rescue NoMethodError
  nil
end

def initialize(commit)
  @commit = commit
  @errors = []
  @result = {}
  @project_url = nil
  @raw = @commit.file_content PATH
  @project = parse
end

def merge_environment_overrides!
  return unless services = @project.dig(:environments, @environment.to_sym)
  services.each do |name, service|
    service.each do |attribute, value|
      if value.is_a?(Hash) && @result[:services][name][attribute].is_a?(Hash)
        @result[:services][name][attribute].merge! value
        @result[:services][name][attribute].compact!
      else
        @result[:services][name][attribute] = value
      end
    end
  end
end

def parse
  YAML.safe_load @raw, aliases: true, symbolize_names: true
rescue Psych::Exception => exception
  @errors << exception.message
  nil
end

def set_project_url
  @project_url = dig :project
end

def to_deployment_params
  {
    environ: {
      name: @environment,
      project_url: @project_url
    },
    commit: {
      ref: @commit.ref,
      time: @commit.time,
      message: @commit.message
    },
    config: @result,
    raw_config: @raw
  }
end

def transform_env_var_values!
  @result[:services].each do |name, service|
    service.fetch(:env, {}).each do |key, value|
      if value.is_a?(Hash) && value.has_key?(:file)
        @result[:services][name][:env][key] = @commit.file_content(value.fetch(:file)).strip
      end
    end
  end
end

def validate
  return unless @project
  validate_top_level_keys
  validate_services @project.fetch(:services)
  validate_environments
end

def validate_environments
  return unless @project.has_key?(:environments)
  environments = @project.fetch :environments, nil
  unless environments.is_a?(Hash)
    @errors << "`environments` key must be a hash."
    return
  end
  environments.each do |environment, services|
    unless environment =~ NAME_FORMAT
      @errors << "`#{environment}` is not a valid environment name. Allowed characters: a-z, 0-9, -, _"
    end
    validate_services services
  end
end

def validate_services(services)
  unless services.is_a?(Hash)
    @errors << "`services` key must be a hash."
    return
  end
  services.each do |name, service|
    unless name =~ NAME_FORMAT
      @errors << "`#{name}` is not a valid service name. Allowed characters: a-z, 0-9, -, _"
    end
    unless service.is_a?(Hash)
      @errors << "Service `#{name}` must be a hash."
      next
    end
    service.each do |attribute, value|
      unless VALID_SERVICE_KEYS.include?(attribute)
        @errors << "Service `#{name}` attribute `#{attribute}` is not a valid attribute."
      end
    end
    BUILD_DEFAULTS.each do |attribute, options|
      value = service.fetch(attribute, options.first)
      unless @commit.public_send(options.second, value)
        @errors << "Service `#{name}` specifies `#{attribute}` as `#{value}` which doesn't exist in this commit."
      end
    end
    service.fetch(:env, {}).each do |key, value|
      if value.is_a?(Hash) && value.has_key?(:file)
        unless @commit.file_exists?(value.fetch(:file))
          @errors << "Environment variable `#{key}` referring to a file `#{value.fetch(:file)}` doesn't exist in this commit."
        end
      end
    end
  end
end

def validate_top_level_keys
  unless @project.is_a?(Hash)
    @errors << "Config doesn't contain a top level hash structure."
    return
  end
  @errors << "Missing `project: <url>` top level attribute." if @project[:project].blank?
  @project.keys.each do |key|
    unless VALID_TOP_LEVEL_KEYS.include?(key)
      @errors << "Top level key `#{key}` is not allowed. Allowed keys: #{VALID_TOP_LEVEL_KEYS.map{ "`#{_1}`" }.join(", ")}."
    end
  end
end