package fasthttp

import (
	"fmt"
	"sync/atomic"
)

// HTTP status codes were stolen from net/http.
const (
	StatusContinue           = 100
	StatusSwitchingProtocols = 101

	StatusOK                   = 200
	StatusCreated              = 201
	StatusAccepted             = 202
	StatusNonAuthoritativeInfo = 203
	StatusNoContent            = 204
	StatusResetContent         = 205
	StatusPartialContent       = 206

	StatusMultipleChoices   = 300
	StatusMovedPermanently  = 301
	StatusFound             = 302
	StatusSeeOther          = 303
	StatusNotModified       = 304
	StatusUseProxy          = 305
	StatusTemporaryRedirect = 307

	StatusBadRequest                   = 400
	StatusUnauthorized                 = 401
	StatusPaymentRequired              = 402
	StatusForbidden                    = 403
	StatusNotFound                     = 404
	StatusMethodNotAllowed             = 405
	StatusNotAcceptable                = 406
	StatusProxyAuthRequired            = 407
	StatusRequestTimeout               = 408
	StatusConflict                     = 409
	StatusGone                         = 410
	StatusLengthRequired               = 411
	StatusPreconditionFailed           = 412
	StatusRequestEntityTooLarge        = 413
	StatusRequestURITooLong            = 414
	StatusUnsupportedMediaType         = 415
	StatusRequestedRangeNotSatisfiable = 416
	StatusExpectationFailed            = 417
	StatusTeapot                       = 418
	StatusPreconditionRequired         = 428
	StatusTooManyRequests              = 429
	StatusRequestHeaderFieldsTooLarge  = 431

	StatusInternalServerError           = 500
	StatusNotImplemented                = 501
	StatusBadGateway                    = 502
	StatusServiceUnavailable            = 503
	StatusGatewayTimeout                = 504
	StatusHTTPVersionNotSupported       = 505
	StatusNetworkAuthenticationRequired = 511
)

var (
	statusLines atomic.Value

	statusMessages = map[int]string{
		StatusContinue:           "Continue",
		StatusSwitchingProtocols: "SwitchingProtocols",

		StatusOK:                   "OK",
		StatusCreated:              "Created",
		StatusAccepted:             "Accepted",
		StatusNonAuthoritativeInfo: "Non-Authoritative Info",
		StatusNoContent:            "No Content",
		StatusResetContent:         "Reset Content",
		StatusPartialContent:       "Partial Content",

		StatusMultipleChoices:   "Multiple Choices",
		StatusMovedPermanently:  "Moved Permanently",
		StatusFound:             "Found",
		StatusSeeOther:          "See Other",
		StatusNotModified:       "Not Modified",
		StatusUseProxy:          "Use Proxy",
		StatusTemporaryRedirect: "Temporary Redirect",

		StatusBadRequest:                   "Bad Request",
		StatusUnauthorized:                 "Unauthorized",
		StatusPaymentRequired:              "Payment Required",
		StatusForbidden:                    "Forbidden",
		StatusNotFound:                     "Not Found",
		StatusMethodNotAllowed:             "Method Not Allowed",
		StatusNotAcceptable:                "Not Acceptable",
		StatusProxyAuthRequired:            "Proxy Auth Required",
		StatusRequestTimeout:               "Request Timeout",
		StatusConflict:                     "Conflict",
		StatusGone:                         "Gone",
		StatusLengthRequired:               "Length Required",
		StatusPreconditionFailed:           "Precondition Failed",
		StatusRequestEntityTooLarge:        "Request Entity Too Large",
		StatusRequestURITooLong:            "Request URI Too Long",
		StatusUnsupportedMediaType:         "Unsupported Media Type",
		StatusRequestedRangeNotSatisfiable: "Requested Range Not Satisfiable",
		StatusExpectationFailed:            "Expectation Failed",
		StatusTeapot:                       "Teapot",
		StatusPreconditionRequired:         "Precondition Required",
		StatusTooManyRequests:              "Too Many Requests",
		StatusRequestHeaderFieldsTooLarge:  "Request HeaderFields Too Large",

		StatusInternalServerError:           "Internal Server Error",
		StatusNotImplemented:                "Not Implemented",
		StatusBadGateway:                    "Bad Gateway",
		StatusServiceUnavailable:            "Service Unavailable",
		StatusGatewayTimeout:                "Gateway Timeout",
		StatusHTTPVersionNotSupported:       "HTTP Version Not Supported",
		StatusNetworkAuthenticationRequired: "Network Authentication Required",
	}
)

// StatusMessage returns HTTP status message for the given status code.
func StatusMessage(statusCode int) string {
	s := statusMessages[statusCode]
	if s == "" {
		s = "Unknown Status Code"
	}
	return s
}

func init() {
	statusLines.Store(make(map[int][]byte))
}

func statusLine(statusCode int) []byte {
	m := statusLines.Load().(map[int][]byte)
	h := m[statusCode]
	if h != nil {
		return h
	}

	statusText := StatusMessage(statusCode)

	h = []byte(fmt.Sprintf("HTTP/1.1 %d %s\r\n", statusCode, statusText))
	newM := make(map[int][]byte, len(m)+1)
	for k, v := range m {
		newM[k] = v
	}
	newM[statusCode] = h
	statusLines.Store(newM)
	return h
}