package fasthttp_client

import (
	"fmt"
	"net"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/eolinker/eosc/eocontext"

	"github.com/valyala/fasthttp"
)

type Addr struct {
	IP   net.IP
	Port int
}

func resolveAddr(scheme string, addr string) (*Addr, error) {
	as := strings.Split(addr, ":")
	if len(as) < 2 {
		if scheme == "http" {
			addr = fmt.Sprintf("%s:80", addr)
		} else if scheme == "https" {
			addr = fmt.Sprintf("%s:443", addr)
		}
	}
	tcpAddr, err := net.ResolveTCPAddr("tcp", addr)
	if err != nil {
		return nil, err
	}
	return &Addr{
		IP:   tcpAddr.IP,
		Port: tcpAddr.Port,
	}, nil
}

func ProxyTimeout(scheme string, node eocontext.INode, req *fasthttp.Request, resp *fasthttp.Response, timeout time.Duration) (*Addr, error) {
	tcpAddr, err := resolveAddr(scheme, node.Addr())
	if err != nil {
		return nil, err
	}
	addr := fmt.Sprintf("%s://%s:%d", scheme, tcpAddr.IP.String(), tcpAddr.Port)
	err = defaultClient.ProxyTimeout(addr, req, resp, timeout)
	if err != nil {
		node.Down()
	}
	return tcpAddr, err
}

var defaultClient Client

const (
	DefaultMaxConns           = 10240
	DefaultMaxConnWaitTimeout = time.Second * 60
	DefaultMaxRedirectCount   = 2
)

// Client implements http client.
//
// Copying Client by value is prohibited. Create new instance instead.
//
// It is safe calling Client methods from concurrently running goroutines.
//
// The fields of a Client should not be changed while it is in use.
type Client struct {
	mLock sync.Mutex
	m     map[string]*fasthttp.HostClient
	ms    map[string]*fasthttp.HostClient
}

func readAddress(addr string) (scheme, host string) {
	if i := strings.Index(addr, "://"); i > 0 {
		return strings.ToLower(addr[:i]), addr[i+3:]
	}
	return "http", addr
}

func (c *Client) getHostClient(addr string) (*fasthttp.HostClient, string, error) {

	scheme, host := readAddress(addr)

	isTLS := false
	if strings.EqualFold(scheme, "https") {
		isTLS = true
	} else if !strings.EqualFold(scheme, "http") {
		return nil, "", fmt.Errorf("unsupported protocol %q. http and https are supported", scheme)
	}

	startCleaner := false

	c.mLock.Lock()
	m := c.m
	if isTLS {
		m = c.ms
	}
	if m == nil {
		m = make(map[string]*fasthttp.HostClient)
		if isTLS {
			c.ms = m
		} else {
			c.m = m
		}
	}
	hc := m[host]
	if hc == nil {
		hc = &fasthttp.HostClient{
			Addr:               addMissingPort(host, isTLS),
			IsTLS:              isTLS,
			Dial:               Dial,
			MaxConns:           DefaultMaxConns,
			MaxConnWaitTimeout: DefaultMaxConnWaitTimeout,
			RetryIf: func(request *fasthttp.Request) bool {
				return false
			},
		}
		m[host] = hc
		if len(m) == 1 {
			startCleaner = true
		}
	}
	c.mLock.Unlock()

	if startCleaner {
		go c.mCleaner(m)
	}
	return hc, scheme, nil
}

//func (c *Client) getDialFunc() fasthttp.DialFunc {
//	return func(addr string) (net.Conn, error) {
//		atomic.AddInt64(&dialCount, 1)
//		conn, err := tcpDial.Dial(addr)
//		if err != nil {
//			return nil, err
//		}
//		c.conn = conn
//		return &debugConn{Conn: conn}, nil
//	}
//}
//
//func (c *Client) RemoteAddr() string {
//	if c.conn != nil {
//		return c.conn.RemoteAddr().String()
//	}
//	return "unknown"
//}
//
//func (c *Client) LocalAddr() string {
//	if c.conn != nil {
//		return c.conn.RemoteAddr().String()
//	}
//	return "unknown"
//}

// ProxyTimeout performs the given request and waits for response during
// the given timeout duration.
//
// Request must contain at least non-zero RequestURI with full url (including
// scheme and host) or non-zero Host header + RequestURI.
//
// Client determines the server to be requested in the following order:
//
//   - from RequestURI if it contains full url with scheme and host;
//   - from Host header otherwise.
//
// The function doesn't follow redirects. Use Get* for following redirects.
//
// Response is ignored if resp is nil.
//
// ErrTimeout is returned if the response wasn't returned during
// the given timeout.
//
// ErrNoFreeConns is returned if all Client.MaxConnsPerHost connections
// to the requested host are busy.
//
// It is recommended obtaining req and resp via AcquireRequest
// and AcquireResponse in performance-critical code.
//
// Warning: ProxyTimeout does not terminate the request itself. The request will
// continue in the background and the response will be discarded.
// If requests take too long and the connection pool gets filled up please
// try setting a ReadTimeout.
func (c *Client) ProxyTimeout(addr string, req *fasthttp.Request, resp *fasthttp.Response, timeout time.Duration) error {
	client, scheme, err := c.getHostClient(addr)
	if err != nil {
		return err
	}

	request := req
	request.URI().SetScheme(scheme)
	request.Header.ResetConnectionClose()
	request.Header.Set("Connection", "keep-alive")

	connectionClose := resp.ConnectionClose()
	err = client.DoTimeout(request, resp, timeout)
	if err != nil {
		return err
	}
	if fasthttp.StatusCodeIsRedirect(resp.StatusCode()) {
		err = client.DoRedirects(request, resp, DefaultMaxRedirectCount)
		if err != nil {
			return err
		}
	}

	if connectionClose {
		resp.SetConnectionClose()
	}
	return nil
}

func (c *Client) mCleaner(m map[string]*fasthttp.HostClient) {
	mustStop := false

	//sleep := c.MaxIdleConnDuration
	//if sleep < time.Second {
	//	sleep = time.Second
	//} else if sleep > 10*time.Second {
	//	sleep = 10 * time.Second
	//}
	sleep := time.Second * 10
	for {
		c.mLock.Lock()
		for k, v := range m {
			shouldRemove := v.ConnsCount() == 0
			if shouldRemove {
				delete(m, k)
			}
		}
		if len(m) == 0 {
			mustStop = true
		}

		c.mLock.Unlock()

		if mustStop {
			break
		}
		time.Sleep(sleep)
	}
}

func addMissingPort(addr string, isTLS bool) string {
	n := strings.Index(addr, ":")
	if n >= 0 {
		return addr
	}
	port := 80
	if isTLS {
		port = 443
	}
	return net.JoinHostPort(addr, strconv.Itoa(port))
}