package http

import (
	"bufio"
	"bytes"
	"errors"
	"fmt"
	"io"
	"net"
	"strconv"
	"strings"
)

type HttpTransport struct{}

func (t *HttpTransport) RoundTrip(req *Request) (*Response, error) {
	conn, err := net.Dial("tcp", req.ConnectPath)
	// conn, err := tls.Dial("tcp", connectPath, nil)
	if err != nil {
		return nil, errors.New("connect " + req.ConnectPath)
	}
	defer conn.Close()

	debugWrap(conn, req, writeRequest)
	return readResponse(conn)
}

func writeRequest(w io.Writer, req *Request) {
	fmt.Fprintf(w, "%s %s %s\r\n", req.Method, req.Path, req.Protocol)

	for _, header := range req.Headers {
		fmt.Fprintf(w, "%s: %s\r\n", header.Name, header.Value)
	}
	fmt.Fprintf(w, "\r\n")

	if len(req.Body) > 0 {
		fmt.Fprintf(w, "%s\r\n", req.Body)
	}
}

func debugWrap(w io.Writer, req *Request, f func(w io.Writer, req *Request)) {
	buffer := &bytes.Buffer{}

	f(buffer, req)

	fmt.Println("----- Debug Info -----")
	fmt.Println(buffer.String())
	fmt.Println("----- Debug End Info -----")

	w.Write(buffer.Bytes())
}

func readResponse(r io.Reader) (*Response, error) {
	b := bufio.NewReader(r)

	if _, err := b.ReadString(' '); err != nil {
		return nil, errors.New("read httpVersion")
	}
	statusCodeStr, err := b.ReadString(' ')
	if err != nil {
		return nil, errors.New("read statusCode")
	}
	if _, err := b.ReadString('\r'); err != nil {
		return nil, errors.New("read statusName")
	}
	if _, err := b.ReadString('\n'); err != nil {
		return nil, errors.New("read LF")
	}

	statusCode, err := strconv.Atoi(statusCodeStr[:len(statusCodeStr)-1])
	if err != nil {
		return nil, errors.New("read statusCode")
	}

	headerStr := ""
	contentLengthStr := ""
	headers := []Header{}
	for {
		headerStr, err = b.ReadString('\n')
		if err != nil {
			return nil, errors.New("read header")
		}
		if headerStr == "\r\n" {
			break
		}
		arr := strings.Split(headerStr, ": ")
		value := strings.TrimSpace(arr[1])
		header := Header{Name: arr[0], Value: value}
		if header.Name == "Content-Length" {
			contentLengthStr = header.Value
		}
		headers = append(headers, header)
	}

	length, err := strconv.Atoi(contentLengthStr)
	if err != nil {
		return nil, errors.New("read Content-Length")
	}

	body := make([]byte, 0, length)

	for i := 0; i < length; i++ {
		r, err := b.ReadByte()
		if err != nil {
			return nil, errors.New("read body")
		}
		body = append(body, r)
	}

	return &Response{
		StatusCode: statusCode,
		Headers:    headers,
		Body:       body,
	}, nil
}