package worker

import (
	"context"
	"errors"
	"net"
	"net/http"
	"net/url"
)

var (
	UnsupportedSchemeErr = errors.New("Ivalid schema, only tcp and unix supported")
)

type ServerTask struct {
	addr    string
	handler http.Handler
}

func NewServerTask(addr string, handler http.Handler) *ServerTask {
	return &ServerTask{
		addr:    addr,
		handler: handler,
	}
}

func (s *ServerTask) Start(ctx context.Context) error {
	done := make(chan error)

	listen, err := getListen(s.addr)
	if err != nil {
		return err
	}
	server := &http.Server{
		Handler: s.handler,
	}

	go func() {
		done <- server.Serve(listen)
	}()

	select {
	// if ListenAndServe error for something other than context.Canceled
	//(e.g.: address already in use) it trigger done to return sonner with
	// the return error
	case err := <-done:
		return err

	// in case of context canceled it will manually trigger the server to
	// shutdown, and return its error, which is most cases, but not limited, is
	// context.Canceled.
	case <-ctx.Done():
		return server.Shutdown(ctx)
	}
}

func getListen(addr string) (net.Listener, error) {
	u, err := url.Parse(addr)
	if err != nil {
		return nil, err
	}

	switch u.Scheme {
	case "tcp":
		return net.Listen(u.Scheme, u.Host)
	case "unix":
		host, err := url.JoinPath("/", u.Host, u.Path)
		if err != nil {
			return nil, err
		}
		return net.Listen(u.Scheme, host)
	default:
		return nil, UnsupportedSchemeErr
	}
}