//! HTTP status codes
//!
//! This module contains HTTP-status code related structs an errors. The main
//! type in this module is `StatusCode` which is not intended to be used through
//! this module but rather the `http::StatusCode` type.
//!
//! # Examples
//!
//! ```
//! use http::StatusCode;
//!
//! assert_eq!(StatusCode::from_u16(200).unwrap(), StatusCode::OK);
//! assert_eq!(StatusCode::NOT_FOUND, 404);
//! assert!(StatusCode::OK.is_success());
//! ```

use std::fmt;
use std::error::Error;
use std::str::FromStr;

use HttpTryFrom;

/// An HTTP status code (`status-code` in RFC 7230 et al.).
///
/// This type contains constants for all common status codes.
/// It allows status codes in the range [100, 599].
///
/// IANA maintain the [Hypertext Transfer Protocol (HTTP) Status Code
/// Registry](http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml) which is
/// the source for this enum (with one exception, 418 I'm a teapot, which is
/// inexplicably not in the register).
///
/// # Examples
///
/// ```
/// use http::StatusCode;
///
/// assert_eq!(StatusCode::from_u16(200).unwrap(), StatusCode::OK);
/// assert_eq!(StatusCode::NOT_FOUND.as_u16(), 404);
/// assert!(StatusCode::OK.is_success());
/// ```
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct StatusCode(u16);

/// A possible error value when converting a `StatusCode` from a `u16` or `&str`
///
/// This error indicates that the supplied input was not a valid number, was less
/// than 100, or was greater than 599.
#[derive(Debug)]
pub struct InvalidStatusCode {
    _priv: (),
}

impl StatusCode {
    /// Converts a u16 to a status code.
    ///
    /// The function validates the correctness of the supplied u16. It must be
    /// greater or equal to 100 but less than 600.
    ///
    /// # Example
    ///
    /// ```
    /// use http::StatusCode;
    ///
    /// let ok = StatusCode::from_u16(200).unwrap();
    /// assert_eq!(ok, StatusCode::OK);
    ///
    /// let err = StatusCode::from_u16(99);
    /// assert!(err.is_err());
    /// ```
    #[inline]
    pub fn from_u16(src: u16) -> Result<StatusCode, InvalidStatusCode> {
        if src < 100 || src >= 600 {
            return Err(InvalidStatusCode::new());
        }

        Ok(StatusCode(src))
    }

    /// Converts a &[u8] to a status code
    pub fn from_bytes(src: &[u8]) -> Result<StatusCode, InvalidStatusCode> {
        if src.len() != 3 {
            return Err(InvalidStatusCode::new());
        }

        let a = src[0].wrapping_sub(b'0') as u16;
        let b = src[1].wrapping_sub(b'0') as u16;
        let c = src[2].wrapping_sub(b'0') as u16;

        if a == 0 || a > 5 || b > 9 || c > 9 {
            return Err(InvalidStatusCode::new());
        }

        let status = (a * 100) + (b * 10) + c;
        Ok(StatusCode(status))
    }

    /// Returns the `u16` corresponding to this `StatusCode`.
    ///
    /// # Note
    ///
    /// This is the same as the `From<StatusCode>` implementation, but
    /// included as an inherent method because that implementation doesn't
    /// appear in rustdocs, as well as a way to force the type instead of
    /// relying on inference.
    ///
    /// # Example
    ///
    /// ```
    /// let status = http::StatusCode::OK;
    /// assert_eq!(status.as_u16(), 200);
    /// ```
    #[inline]
    pub fn as_u16(&self) -> u16 {
        (*self).into()
    }

    /// Returns a &str representation of the `StatusCode`
    ///
    /// The return value only includes a numerical representation of the
    /// status code. The canonical reason is not included.
    ///
    /// # Example
    ///
    /// ```
    /// let status = http::StatusCode::OK;
    /// assert_eq!(status.as_str(), "200");
    /// ```
    #[inline]
    pub fn as_str(&self) -> &str {
        CODES_AS_STR[(self.0 - 100) as usize]
    }

    /// Get the standardised `reason-phrase` for this status code.
    ///
    /// This is mostly here for servers writing responses, but could potentially have application
    /// at other times.
    ///
    /// The reason phrase is defined as being exclusively for human readers. You should avoid
    /// deriving any meaning from it at all costs.
    ///
    /// Bear in mind also that in HTTP/2.0 the reason phrase is abolished from transmission, and so
    /// this canonical reason phrase really is the only reason phrase you’ll find.
    ///
    /// # Example
    ///
    /// ```
    /// let status = http::StatusCode::OK;
    /// assert_eq!(status.canonical_reason(), Some("OK"));
    /// ```
    pub fn canonical_reason(&self) -> Option<&'static str> {
        canonical_reason(self.0)
    }


    /// Check if status is within 100-199.
    #[inline]
    pub fn is_informational(&self) -> bool {
        200 > self.0 && self.0 >= 100
    }

    /// Check if status is within 200-299.
    #[inline]
    pub fn is_success(&self) -> bool {
        300 > self.0 && self.0 >= 200
    }

    /// Check if status is within 300-399.
    #[inline]
    pub fn is_redirection(&self) -> bool {
        400 > self.0 && self.0 >= 300
    }

    /// Check if status is within 400-499.
    #[inline]
    pub fn is_client_error(&self) -> bool {
        500 > self.0 && self.0 >= 400
    }

    /// Check if status is within 500-599.
    #[inline]
    pub fn is_server_error(&self) -> bool {
        600 > self.0 && self.0 >= 500
    }
}

impl fmt::Debug for StatusCode {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        fmt::Debug::fmt(&self.0, f)
    }
}

/// Formats the status code, *including* the canonical reason.
///
/// # Example
///
/// ```
/// # use http::StatusCode;
/// assert_eq!(format!("{}", StatusCode::OK), "200 OK");
/// ```
impl fmt::Display for StatusCode {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{} {}", u16::from(*self),
               self.canonical_reason().unwrap_or("<unknown status code>"))
    }
}

impl Default for StatusCode {
    #[inline]
    fn default() -> StatusCode {
        StatusCode::OK
    }
}

impl PartialEq<u16> for StatusCode {
    #[inline]
    fn eq(&self, other: &u16) -> bool {
        self.as_u16() == *other
    }
}

impl PartialEq<StatusCode> for u16 {
    #[inline]
    fn eq(&self, other: &StatusCode) -> bool {
        *self == other.as_u16()
    }
}

impl From<StatusCode> for u16 {
    #[inline]
    fn from(status: StatusCode) -> u16 {
        status.0
    }
}

impl FromStr for StatusCode {
    type Err = InvalidStatusCode;

    fn from_str(s: &str) -> Result<StatusCode, InvalidStatusCode> {
        StatusCode::from_bytes(s.as_ref())
    }
}

impl<'a> HttpTryFrom<&'a [u8]> for StatusCode {
    type Error = InvalidStatusCode;

    #[inline]
    fn try_from(t: &'a [u8]) -> Result<Self, Self::Error> {
        StatusCode::from_bytes(t)
    }
}

impl<'a> HttpTryFrom<&'a str> for StatusCode {
    type Error = InvalidStatusCode;

    #[inline]
    fn try_from(t: &'a str) -> Result<Self, Self::Error> {
        t.parse()
    }
}

impl HttpTryFrom<u16> for StatusCode {
    type Error = InvalidStatusCode;

    #[inline]
    fn try_from(t: u16) -> Result<Self, Self::Error> {
        StatusCode::from_u16(t)
    }
}

impl InvalidStatusCode {
    fn new() -> InvalidStatusCode {
        InvalidStatusCode {
            _priv: (),
        }
    }
}

macro_rules! status_codes {
    (
        $(
            $(#[$docs:meta])*
            ($num:expr, $konst:ident, $phrase:expr);
        )+
    ) => {
        impl StatusCode {
        $(
            $(#[$docs])*
            pub const $konst: StatusCode = StatusCode($num);
        )+

        }

        fn canonical_reason(num: u16) -> Option<&'static str> {
            match num {
                $(
                $num => Some($phrase),
                )+
                _ => None
            }
        }
    }
}

status_codes! {
    /// 100 Continue
    /// [[RFC7231, Section 6.2.1](https://tools.ietf.org/html/rfc7231#section-6.2.1)]
    (100, CONTINUE, "Continue");
    /// 101 Switching Protocols
    /// [[RFC7231, Section 6.2.2](https://tools.ietf.org/html/rfc7231#section-6.2.2)]
    (101, SWITCHING_PROTOCOLS, "Switching Protocols");
    /// 102 Processing
    /// [[RFC2518](https://tools.ietf.org/html/rfc2518)]
    (102, PROCESSING, "Processing");

    /// 200 OK
    /// [[RFC7231, Section 6.3.1](https://tools.ietf.org/html/rfc7231#section-6.3.1)]
    (200, OK, "OK");
    /// 201 Created
    /// [[RFC7231, Section 6.3.2](https://tools.ietf.org/html/rfc7231#section-6.3.2)]
    (201, CREATED, "Created");
    /// 202 Accepted
    /// [[RFC7231, Section 6.3.3](https://tools.ietf.org/html/rfc7231#section-6.3.3)]
    (202, ACCEPTED, "Accepted");
    /// 203 Non-Authoritative Information
    /// [[RFC7231, Section 6.3.4](https://tools.ietf.org/html/rfc7231#section-6.3.4)]
    (203, NON_AUTHORITATIVE_INFORMATION, "Non Authoritative Information");
    /// 204 No Content
    /// [[RFC7231, Section 6.3.5](https://tools.ietf.org/html/rfc7231#section-6.3.5)]
    (204, NO_CONTENT, "No Content");
    /// 205 Reset Content
    /// [[RFC7231, Section 6.3.6](https://tools.ietf.org/html/rfc7231#section-6.3.6)]
    (205, RESET_CONTENT, "Reset Content");
    /// 206 Partial Content
    /// [[RFC7233, Section 4.1](https://tools.ietf.org/html/rfc7233#section-4.1)]
    (206, PARTIAL_CONTENT, "Partial Content");
    /// 207 Multi-Status
    /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
    (207, MULTI_STATUS, "Multi-Status");
    /// 208 Already Reported
    /// [[RFC5842](https://tools.ietf.org/html/rfc5842)]
    (208, ALREADY_REPORTED, "Already Reported");

    /// 226 IM Used
    /// [[RFC3229](https://tools.ietf.org/html/rfc3229)]
    (226, IM_USED, "IM Used");

    /// 300 Multiple Choices
    /// [[RFC7231, Section 6.4.1](https://tools.ietf.org/html/rfc7231#section-6.4.1)]
    (300, MULTIPLE_CHOICES, "Multiple Choices");
    /// 301 Moved Permanently
    /// [[RFC7231, Section 6.4.2](https://tools.ietf.org/html/rfc7231#section-6.4.2)]
    (301, MOVED_PERMANENTLY, "Moved Permanently");
    /// 302 Found
    /// [[RFC7231, Section 6.4.3](https://tools.ietf.org/html/rfc7231#section-6.4.3)]
    (302, FOUND, "Found");
    /// 303 See Other
    /// [[RFC7231, Section 6.4.4](https://tools.ietf.org/html/rfc7231#section-6.4.4)]
    (303, SEE_OTHER, "See Other");
    /// 304 Not Modified
    /// [[RFC7232, Section 4.1](https://tools.ietf.org/html/rfc7232#section-4.1)]
    (304, NOT_MODIFIED, "Not Modified");
    /// 305 Use Proxy
    /// [[RFC7231, Section 6.4.5](https://tools.ietf.org/html/rfc7231#section-6.4.5)]
    (305, USE_PROXY, "Use Proxy");
    /// 307 Temporary Redirect
    /// [[RFC7231, Section 6.4.7](https://tools.ietf.org/html/rfc7231#section-6.4.7)]
    (307, TEMPORARY_REDIRECT, "Temporary Redirect");
    /// 308 Permanent Redirect
    /// [[RFC7238](https://tools.ietf.org/html/rfc7238)]
    (308, PERMANENT_REDIRECT, "Permanent Redirect");

    /// 400 Bad Request
    /// [[RFC7231, Section 6.5.1](https://tools.ietf.org/html/rfc7231#section-6.5.1)]
    (400, BAD_REQUEST, "Bad Request");
    /// 401 Unauthorized
    /// [[RFC7235, Section 3.1](https://tools.ietf.org/html/rfc7235#section-3.1)]
    (401, UNAUTHORIZED, "Unauthorized");
    /// 402 Payment Required
    /// [[RFC7231, Section 6.5.2](https://tools.ietf.org/html/rfc7231#section-6.5.2)]
    (402, PAYMENT_REQUIRED, "Payment Required");
    /// 403 Forbidden
    /// [[RFC7231, Section 6.5.3](https://tools.ietf.org/html/rfc7231#section-6.5.3)]
    (403, FORBIDDEN, "Forbidden");
    /// 404 Not Found
    /// [[RFC7231, Section 6.5.4](https://tools.ietf.org/html/rfc7231#section-6.5.4)]
    (404, NOT_FOUND, "Not Found");
    /// 405 Method Not Allowed
    /// [[RFC7231, Section 6.5.5](https://tools.ietf.org/html/rfc7231#section-6.5.5)]
    (405, METHOD_NOT_ALLOWED, "Method Not Allowed");
    /// 406 Not Acceptable
    /// [[RFC7231, Section 6.5.6](https://tools.ietf.org/html/rfc7231#section-6.5.6)]
    (406, NOT_ACCEPTABLE, "Not Acceptable");
    /// 407 Proxy Authentication Required
    /// [[RFC7235, Section 3.2](https://tools.ietf.org/html/rfc7235#section-3.2)]
    (407, PROXY_AUTHENTICATION_REQUIRED, "Proxy Authentication Required");
    /// 408 Request Timeout
    /// [[RFC7231, Section 6.5.7](https://tools.ietf.org/html/rfc7231#section-6.5.7)]
    (408, REQUEST_TIMEOUT, "Request Timeout");
    /// 409 Conflict
    /// [[RFC7231, Section 6.5.8](https://tools.ietf.org/html/rfc7231#section-6.5.8)]
    (409, CONFLICT, "Conflict");
    /// 410 Gone
    /// [[RFC7231, Section 6.5.9](https://tools.ietf.org/html/rfc7231#section-6.5.9)]
    (410, GONE, "Gone");
    /// 411 Length Required
    /// [[RFC7231, Section 6.5.10](https://tools.ietf.org/html/rfc7231#section-6.5.10)]
    (411, LENGTH_REQUIRED, "Length Required");
    /// 412 Precondition Failed
    /// [[RFC7232, Section 4.2](https://tools.ietf.org/html/rfc7232#section-4.2)]
    (412, PRECONDITION_FAILED, "Precondition Failed");
    /// 413 Payload Too Large
    /// [[RFC7231, Section 6.5.11](https://tools.ietf.org/html/rfc7231#section-6.5.11)]
    (413, PAYLOAD_TOO_LARGE, "Payload Too Large");
    /// 414 URI Too Long
    /// [[RFC7231, Section 6.5.12](https://tools.ietf.org/html/rfc7231#section-6.5.12)]
    (414, URI_TOO_LONG, "URI Too Long");
    /// 415 Unsupported Media Type
    /// [[RFC7231, Section 6.5.13](https://tools.ietf.org/html/rfc7231#section-6.5.13)]
    (415, UNSUPPORTED_MEDIA_TYPE, "Unsupported Media Type");
    /// 416 Range Not Satisfiable
    /// [[RFC7233, Section 4.4](https://tools.ietf.org/html/rfc7233#section-4.4)]
    (416, RANGE_NOT_SATISFIABLE, "Range Not Satisfiable");
    /// 417 Expectation Failed
    /// [[RFC7231, Section 6.5.14](https://tools.ietf.org/html/rfc7231#section-6.5.14)]
    (417, EXPECTATION_FAILED, "Expectation Failed");
    /// 418 I'm a teapot
    /// [curiously not registered by IANA but [RFC2324](https://tools.ietf.org/html/rfc2324)]
    (418, IM_A_TEAPOT, "I'm a teapot");

    /// 421 Misdirected Request
    /// [RFC7540, Section 9.1.2](http://tools.ietf.org/html/rfc7540#section-9.1.2)
    (421, MISDIRECTED_REQUEST, "Misdirected Request");
    /// 422 Unprocessable Entity
    /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
    (422, UNPROCESSABLE_ENTITY, "Unprocessable Entity");
    /// 423 Locked
    /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
    (423, LOCKED, "Locked");
    /// 424 Failed Dependency
    /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
    (424, FAILED_DEPENDENCY, "Failed Dependency");

    /// 426 Upgrade Required
    /// [[RFC7231, Section 6.5.15](https://tools.ietf.org/html/rfc7231#section-6.5.15)]
    (426, UPGRADE_REQUIRED, "Upgrade Required");

    /// 428 Precondition Required
    /// [[RFC6585](https://tools.ietf.org/html/rfc6585)]
    (428, PRECONDITION_REQUIRED, "Precondition Required");
    /// 429 Too Many Requests
    /// [[RFC6585](https://tools.ietf.org/html/rfc6585)]
    (429, TOO_MANY_REQUESTS, "Too Many Requests");

    /// 431 Request Header Fields Too Large
    /// [[RFC6585](https://tools.ietf.org/html/rfc6585)]
    (431, REQUEST_HEADER_FIELDS_TOO_LARGE, "Request Header Fields Too Large");

    /// 451 Unavailable For Legal Reasons
    /// [[RFC7725](http://tools.ietf.org/html/rfc7725)]
    (451, UNAVAILABLE_FOR_LEGAL_REASONS, "Unavailable For Legal Reasons");

    /// 500 Internal Server Error
    /// [[RFC7231, Section 6.6.1](https://tools.ietf.org/html/rfc7231#section-6.6.1)]
    (500, INTERNAL_SERVER_ERROR, "Internal Server Error");
    /// 501 Not Implemented
    /// [[RFC7231, Section 6.6.2](https://tools.ietf.org/html/rfc7231#section-6.6.2)]
    (501, NOT_IMPLEMENTED, "Not Implemented");
    /// 502 Bad Gateway
    /// [[RFC7231, Section 6.6.3](https://tools.ietf.org/html/rfc7231#section-6.6.3)]
    (502, BAD_GATEWAY, "Bad Gateway");
    /// 503 Service Unavailable
    /// [[RFC7231, Section 6.6.4](https://tools.ietf.org/html/rfc7231#section-6.6.4)]
    (503, SERVICE_UNAVAILABLE, "Service Unavailable");
    /// 504 Gateway Timeout
    /// [[RFC7231, Section 6.6.5](https://tools.ietf.org/html/rfc7231#section-6.6.5)]
    (504, GATEWAY_TIMEOUT, "Gateway Timeout");
    /// 505 HTTP Version Not Supported
    /// [[RFC7231, Section 6.6.6](https://tools.ietf.org/html/rfc7231#section-6.6.6)]
    (505, HTTP_VERSION_NOT_SUPPORTED, "HTTP Version Not Supported");
    /// 506 Variant Also Negotiates
    /// [[RFC2295](https://tools.ietf.org/html/rfc2295)]
    (506, VARIANT_ALSO_NEGOTIATES, "Variant Also Negotiates");
    /// 507 Insufficient Storage
    /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
    (507, INSUFFICIENT_STORAGE, "Insufficient Storage");
    /// 508 Loop Detected
    /// [[RFC5842](https://tools.ietf.org/html/rfc5842)]
    (508, LOOP_DETECTED, "Loop Detected");

    /// 510 Not Extended
    /// [[RFC2774](https://tools.ietf.org/html/rfc2774)]
    (510, NOT_EXTENDED, "Not Extended");
    /// 511 Network Authentication Required
    /// [[RFC6585](https://tools.ietf.org/html/rfc6585)]
    (511, NETWORK_AUTHENTICATION_REQUIRED, "Network Authentication Required");
}

impl fmt::Display for InvalidStatusCode {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_str(self.description())
    }
}

impl Error for InvalidStatusCode {
    fn description(&self) -> &str {
        "invalid status code"
    }
}

macro_rules! status_code_strs {
    ($($num:expr,)+) => {
        const CODES_AS_STR: [&'static str; 500] = [ $( stringify!($num), )+ ];
    }
}

status_code_strs!(
    100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119,
    120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139,
    140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159,
    160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179,
    180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199,

    200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219,
    220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239,
    240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259,
    260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279,
    280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299,

    300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319,
    320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339,
    340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359,
    360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379,
    380, 381, 382, 383, 384, 385, 386, 387, 388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399,

    400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419,
    420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432, 433, 434, 435, 436, 437, 438, 439,
    440, 441, 442, 443, 444, 445, 446, 447, 448, 449, 450, 451, 452, 453, 454, 455, 456, 457, 458, 459,
    460, 461, 462, 463, 464, 465, 466, 467, 468, 469, 470, 471, 472, 473, 474, 475, 476, 477, 478, 479,
    480, 481, 482, 483, 484, 485, 486, 487, 488, 489, 490, 491, 492, 493, 494, 495, 496, 497, 498, 499,

    500, 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519,
    520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534, 535, 536, 537, 538, 539,
    540, 541, 542, 543, 544, 545, 546, 547, 548, 549, 550, 551, 552, 553, 554, 555, 556, 557, 558, 559,
    560, 561, 562, 563, 564, 565, 566, 567, 568, 569, 570, 571, 572, 573, 574, 575, 576, 577, 578, 579,
    580, 581, 582, 583, 584, 585, 586, 587, 588, 589, 590, 591, 592, 593, 594, 595, 596, 597, 598, 599,
    );