require 'socket'
require 'uri'
require 'json'

#
# minimal http server for DataPipeline::RestStorage tests, one request per connection
#   server = TestHttpServer.new { |req| [200, { 'items' => [] }] }
#   req: { method:, path:, query:, headers:, body: }  -> [status, hash/array or string]
#
class TestHttpServer
  attr_reader :requests

  def initialize(&handler)
    @handler = handler
    @requests = []
    @server = TCPServer.new('127.0.0.1', 0)
    @thread = Thread.new { loop { serve(@server.accept) } }
  end

  def url = "http://127.0.0.1:#{@server.addr[1]}"

  def stop
    @thread.kill
    @server.close
  end

  private

  def serve client
    method, target = client.gets.to_s.split
    return unless method

    headers = {}
    while (line = client.gets) && line != "\r\n"
      key, value = line.split(':', 2)
      headers[key.downcase] = value.strip
    end
    body = headers['content-length'] ? client.read(headers['content-length'].to_i) : ''
    path, query = target.split('?', 2)
    request = { method:, path:, query: URI.decode_www_form(query.to_s).to_h, headers:, body: }
    @requests << request

    status, payload = @handler.call(request)
    text = payload.is_a?(String) ? payload : JSON.generate(payload)
    client.write "HTTP/1.1 #{status} X\r\nContent-Type: application/json\r\n" \
                 "Content-Length: #{text.bytesize}\r\nConnection: close\r\n\r\n#{text}"
  rescue StandardError => e
    warn "TestHttpServer: #{e.class}: #{e.message}"
  ensure
    client.close
  end
end