package http

import (
	"errors"
	"fmt"
	"strconv"
)

// ResponseEncode 编码器, 把response编码为字节流并写入缓冲区
type ResponseEncode struct{}

func (r *ResponseEncode) Encode(response *Response) (err error) {
	defer func() {
		if e := recover(); e != nil {
			err = errors.New(fmt.Sprintln("Error encoding response,", e))
		}
	}()

	if response == nil {
		return errors.New("response cannot be nil")
	}
	if response.BufWriter == nil {
		return errors.New("response.BufWriter cannot be nil")
	}
	r.line(response)
	r.header(response)
	r.body(response)
	return response.BufWriter.Flush()
}

func (r *ResponseEncode) line(response *Response) {
	if err := response.BufWriter.WriteString(response.Proto + " "); err != nil {
		panic(err)
	}
	if err := response.BufWriter.WriteString(strconv.Itoa(response.statusCode) + " "); err != nil {
		panic(err)
	}
	if err := response.BufWriter.WriteString(response.statusText); err != nil {
		panic(err)
	}
	if err := response.BufWriter.WriteBytes(crlf); err != nil {
		panic(err)
	}
}

func (r *ResponseEncode) header(response *Response) {
	buffer := response.BufWriter.WriteBuffer()

	if response.Server != "" {
		if err := writeHeader(buffer, "Server", response.Server); err != nil {
			panic(err)
		}
	}
	if response.body != nil && response.body.size > 0 {
		if err := writeHeader(buffer, "Content-Length", strconv.FormatInt(response.body.size, 10)); err != nil {
			panic(err)
		}
	}

	if response.Header != nil {
		for name, values := range response.Header {
			if values == nil || len(values) == 0 {
				continue
			}
			for i := 0; i < len(values); i++ {
				if name == "Cookie" {
					r.cookie(response)
					continue
				}
				if err := writeHeader(buffer, name, values[i]); err != nil {
					panic(err)
				}
			}
		}
	}
	if err := response.BufWriter.WriteBytes(crlf); err != nil {
		panic(err)
	}
}

// 编码cookie
func (r *ResponseEncode) cookie(response *Response) {
	cookies := response.Cookies()
	if cookies == nil {
		return
	}
	for _, cookie := range cookies[:] {
		if err := writeHeader(response.BufWriter.WriteBuffer(), "Set-Cookie", cookie.String()); err != nil {
			panic(err)
		}
	}
}

func (r *ResponseEncode) body(response *Response) {
	if response.body != nil && response.body.size > 0 {
		if _, err := response.BufWriter.WriteBuffer().ReadFrom(response.body); err != nil {
			panic(err)
		}
	}
}

func NewResponseEncode() *ResponseEncode {
	return &ResponseEncode{}
}