require "net/http/persistent"
require "aws-sigv4"

module Paapi
  class Client
    attr_accessor :partner_tag, :marketplace, :resources, :condition
    attr_reader :partner_type, :access_key, :secret_key, :market, :http

    def initialize(
      access_key: Paapi.access_key,
      secret_key: Paapi.secret_key,
      partner_tag: Paapi.partner_tag,
      market: Paapi.market || DEFAULT_MARKET,
      condition: Paapi.condition || DEFAULT_CONDITION,
      resources: Paapi.resources || DEFAULT_RESOURCES,
      partner_type: DEFAULT_PARTNER_TYPE
    )
      raise ArgumentError unless MARKETPLACES.key?(market.to_sym)

      @access_key = access_key
      @secret_key = secret_key
      @partner_type = partner_type
      @resources = resources unless resources.nil?
      @condition = condition
      self.market = market
      @partner_tag = partner_tag if !partner_tag.nil?

      @http = Net::HTTP::Persistent.new(name: "paapi").tap do |c|
        c.open_timeout = 2
        c.read_timeout = 5
        c.write_timeout = 5
      end
    end

    def market=(a_market)
      @market = a_market
      @marketplace = MARKETPLACES[market.to_sym]
      return if Paapi.partner_market.nil?

      @partner_tag = Paapi.partner_market[a_market.to_sym] || @partner_tag
    end

    def get_items(item_ids:, **options)
      payload = {"PartnerTag" => partner_tag, "PartnerType" => "Associates", ItemIds: Array(item_ids), Resources: @resources}.merge(options)
      request(op: :get_items, payload: payload)
    end

    def get_variations(asin:, **options)
      payload = {ASIN: asin, Resources: @resources}.merge(options)
      request(op: :get_variations, payload: payload)
    end

    # TODO: Currently we assume Keywords, but we need one of the following: [Keywords Actor Artist Author Brand Title ]
    def search_items(**options)
      options.transform_keys!(&:to_s)
      raise ArgumentError.new("Missing keywords") unless (options.keys & SEARCH_PARAMS).length.positive?

      search_index = options.dig(:SearchIndex) || "All"

      payload = {"PartnerTag" => partner_tag, "PartnerType" => "Associates", "Resources" => @resources, "ItemCount" => 10, "ItemPage" => 1, "SearchIndex" => search_index}.merge(options)

      request(op: :search_items, payload: payload)
    end

    def get_browse_nodes(browse_node_ids:, **options)
      payload = {BrowseNodeIds: Array(browse_node_ids), Resources: @resources}.merge(options)
      request(op: :get_browse_nodes, payload: payload)
    end

    private

    def request(op:, payload:)
      raise ArguemntError unless Paapi::OPERATIONS.key?(op)

      operation = OPERATIONS[op]

      headers = {
        "X-Amz-Target" => "com.amazon.paapi5.v1.ProductAdvertisingAPIv1.#{operation.target_name}",
        "Content-Encoding" => "amz-1.0"
      }

      default_payload = {
        "Condition" => condition,
        "PartnerTag" => partner_tag,
        "PartnerType" => partner_type,
        "Marketplace" => marketplace.site
      }

      payload = default_payload.merge(payload)
puts payload
      endpoint = "https://#{marketplace.host}/paapi5/#{operation.endpoint_suffix}"

      signer = Aws::Sigv4::Signer.new(
        service: operation.service,
        region: marketplace.region,
        access_key_id: access_key,
        secret_access_key: secret_key,
        http_method: operation.http_method,
        endpoint: marketplace.host
      )

      signature = signer.sign_request(http_method: operation.http_method, url: endpoint, headers: headers, body: payload.to_json)

      headers["Host"] = marketplace.host
      headers["X-Amz-Date"] = signature.headers["x-amz-date"]
      headers["X-Amz-Content-Sha256"] = signature.headers["x-amz-content-sha256"]
      headers["Authorization"] = signature.headers["authorization"]
      headers["Content-Type"] = "application/json; charset=utf-8"

      Response.new(post(url: endpoint, body: payload, headers: headers))
    end

    def post(url:, body:, headers:)
      uri = URI.parse(url)

      post_request = Net::HTTP::Post.new(uri.path)
      post_request.content_type = "application/json; charset=UTF-8"

      headers.each { |k, v| post_request[k] = v }
      post_request.body = body.to_json

      http.request uri, post_request
    end
  end
end