package rtsp

import (
	"bufio"
	"fmt"
	"io"
	"strconv"
)

type Response struct {
	StatusCode int
	Status     string
	Headers    map[string]string
	Content    []byte
}

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

	res := &Response{}

	byts, err := readBytesLimited(rb, ' ', 255)
	if err != nil {
		return nil, err
	}
	proto := string(byts[:len(byts)-1])

	if proto != _RTSP_PROTO {
		return nil, fmt.Errorf("expected '%s', got '%s'", _RTSP_PROTO, proto)
	}

	byts, err = readBytesLimited(rb, ' ', 4)
	if err != nil {
		return nil, err
	}
	statusCodeStr := string(byts[:len(byts)-1])

	statusCode64, err := strconv.ParseInt(statusCodeStr, 10, 32)
	res.StatusCode = int(statusCode64)
	if err != nil {
		return nil, fmt.Errorf("unable to parse status code")
	}

	byts, err = readBytesLimited(rb, '\r', 255)
	if err != nil {
		return nil, err
	}
	res.Status = string(byts[:len(byts)-1])

	if len(res.Status) == 0 {
		return nil, fmt.Errorf("empty status")
	}

	err = readByteEqual(rb, '\n')
	if err != nil {
		return nil, err
	}

	res.Headers, err = readHeaders(rb)
	if err != nil {
		return nil, err
	}

	res.Content, err = readContent(rb, res.Headers)
	if err != nil {
		return nil, err
	}

	return res, nil
}

func responseEncode(w io.Writer, res *Response) error {
	wb := bufio.NewWriter(w)

	_, err := wb.Write([]byte(_RTSP_PROTO + " " + strconv.FormatInt(int64(res.StatusCode), 10) + " " + res.Status + "\r\n"))
	if err != nil {
		return err
	}

	if len(res.Content) != 0 {
		res.Headers["Content-Length"] = strconv.FormatInt(int64(len(res.Content)), 10)
	}

	err = writeHeaders(wb, res.Headers)
	if err != nil {
		return err
	}

	err = writeContent(wb, res.Content)
	if err != nil {
		return err
	}

	return wb.Flush()
}