package miniutils

import (
	"net/http"
	"net/textproto"
	"strconv"
	"strings"
	"time"

	"golang.org/x/net/http/httpguts"
)

// Copy "from net/http"，cookie.go

// readSetCookies parses all "Set-Cookie" values from
// the header h and returns the successfully parsed Cookies.
func ReadSetCookies(h http.Header) []*http.Cookie {
	cookieCount := len(h["Set-Cookie"])
	if cookieCount == 0 {
		return []*http.Cookie{}
	}
	cookies := make([]*http.Cookie, 0, cookieCount)
	for _, line := range h["Set-Cookie"] {
		parts := strings.Split(textproto.TrimString(line), ";")
		if len(parts) == 1 && parts[0] == "" {
			continue
		}
		parts[0] = textproto.TrimString(parts[0])
		name, value, ok := strings.Cut(parts[0], "=")
		if !ok {
			continue
		}
		if !isCookieNameValid(name) {
			continue
		}
		value, ok = parseCookieValue(value, true)
		if !ok {
			continue
		}
		c := &http.Cookie{
			Name:  name,
			Value: value,
			Raw:   line,
		}
		for i := 1; i < len(parts); i++ {
			parts[i] = textproto.TrimString(parts[i])
			if len(parts[i]) == 0 {
				continue
			}

			attr, val, _ := strings.Cut(parts[i], "=")
			lowerAttr, isASCII := asciiToLower(attr)
			if !isASCII {
				continue
			}
			val, ok = parseCookieValue(val, false)
			if !ok {
				c.Unparsed = append(c.Unparsed, parts[i])
				continue
			}

			switch lowerAttr {
			case "samesite":
				lowerVal, ascii := asciiToLower(val)
				if !ascii {
					c.SameSite = http.SameSiteDefaultMode
					continue
				}
				switch lowerVal {
				case "lax":
					c.SameSite = http.SameSiteLaxMode
				case "strict":
					c.SameSite = http.SameSiteStrictMode
				case "none":
					c.SameSite = http.SameSiteNoneMode
				default:
					c.SameSite = http.SameSiteDefaultMode
				}
				continue
			case "secure":
				c.Secure = true
				continue
			case "httponly":
				c.HttpOnly = true
				continue
			case "domain":
				c.Domain = val
				continue
			case "max-age":
				secs, err := strconv.Atoi(val)
				if err != nil || secs != 0 && val[0] == '0' {
					break
				}
				if secs <= 0 {
					secs = -1
				}
				c.MaxAge = secs
				continue
			case "expires":
				c.RawExpires = val
				exptime, err := time.Parse(time.RFC1123, val)
				if err != nil {
					exptime, err = time.Parse("Mon, 02-Jan-2006 15:04:05 MST", val)
					if err != nil {
						c.Expires = time.Time{}
						break
					}
				}
				c.Expires = exptime.UTC()
				continue
			case "path":
				c.Path = val
				continue
			}
			c.Unparsed = append(c.Unparsed, parts[i])
		}
		cookies = append(cookies, c)
	}
	return cookies
}

// readCookies parses all "Cookie" values from the header h and
// returns the successfully parsed Cookies.
//
// if filter isn't empty, only cookies of that name are returned
func ReadCookies(h http.Header, filter string) []*http.Cookie {
	lines := h["Cookie"]
	if len(lines) == 0 {
		return []*http.Cookie{}
	}

	cookies := make([]*http.Cookie, 0, len(lines)+strings.Count(lines[0], ";"))
	for _, line := range lines {
		line = textproto.TrimString(line)

		var part string
		for len(line) > 0 { // continue since we have rest
			part, line, _ = strings.Cut(line, ";")
			part = textproto.TrimString(part)
			if part == "" {
				continue
			}
			name, val, _ := strings.Cut(part, "=")
			if !isCookieNameValid(name) {
				continue
			}
			if filter != "" && filter != name {
				continue
			}
			val, ok := parseCookieValue(val, true)
			if !ok {
				continue
			}
			cookies = append(cookies, &http.Cookie{Name: name, Value: val})
		}
	}
	return cookies
}

func validCookieValueByte(b byte) bool {
	return 0x20 <= b && b < 0x7f && b != '"' && b != ';' && b != '\\'
}

func parseCookieValue(raw string, allowDoubleQuote bool) (string, bool) {
	// Strip the quotes, if present.
	if allowDoubleQuote && len(raw) > 1 && raw[0] == '"' && raw[len(raw)-1] == '"' {
		raw = raw[1 : len(raw)-1]
	}
	for i := 0; i < len(raw); i++ {
		if !validCookieValueByte(raw[i]) {
			return "", false
		}
	}
	return raw, true
}

func isCookieNameValid(raw string) bool {
	if raw == "" {
		return false
	}
	return strings.IndexFunc(raw, isNotToken) < 0
}

func isNotToken(r rune) bool {
	return !httpguts.IsTokenRune(r)
}