//! # HTTP-API-PROBLEM
//!
//! A library to create HTTP response content for APIs based on
//! [RFC7807](https://tools.ietf.org/html/rfc7807)
//!
//! This library depends on [serde](https://serde.rs/).
//!
//! The ```HttpApiProblem``` struct implements `Serialize'.
//!
//! ## Usage
//! 
//! Add this to your `Cargo.toml`:
//!
//! ```toml
//! http-api-problem = { version="0.1.0" }
//! ```
//! 
//! Add this crate root:
//! 
//! ```rust
//! extern crate http_api_problem;
//! ```
//!
//! ## Example
//!
//! ```rust
//! use http_api_problem::*;
//!
//! let p = 
//!     HttpApiProblem::with_type_and_title_from_status(428)
//!     .set_detail("detailed explanation")
//!     .set_instance("/on/1234/do/something");
//!
//! assert_eq!("https://httpstatuses.com/428", p.type_url);
//! assert_eq!(Some(428), p.status);
//! assert_eq!(Some("Precondition Required".to_string()), p.title);
//! assert_eq!(Some("detailed explanation".to_string()), p.detail);
//! assert_eq!(Some("/on/1234/do/something".to_string()), p.instance);
//! ```
//!
//! ## License
//! 
//! `http-api-problem` is primarily distributed under the terms of both the MIT license and the
//! Apache License (Version 2.0).
//! 
//! Copyright (c) 2017 Christian Douven.

extern crate serde;
#[macro_use]
extern crate serde_derive;

/// The recommended media type when serialized to JSON
pub static PROBLEM_JSON_MEDIA_TYPE: &'static str = "application/problem+json";

/// The recommended media type when serialized to XML
pub static PROBLEM_XML_MEDIA_TYPE: &'static str = "application/problem+xml";

/// Description of a problem that can be returned by an HTTP API
/// based on [RFC7807](https://tools.ietf.org/html/rfc7807)
///
/// # Example
///
/// ```javascript
/// {
///    "type": "https://example.com/probs/out-of-credit",
///    "title": "You do not have enough credit.",
///    "detail": "Your current balance is 30, but that costs 50.",
///    "instance": "/account/12345/msgs/abc",
/// }
/// ```
#[derive(Serialize, Deserialize, Debug)]
pub struct HttpApiProblem {
    /// A URI reference [RFC3986](https://tools.ietf.org/html/rfc3986) that identifies the
    /// problem type.  This specification encourages that, when
    /// dereferenced, it provide human-readable documentation for the
    /// problem type (e.g., using HTML [W3C.REC-html5-20141028]).  When
    /// this member is not present, its value is assumed to be
    /// "about:blank".
    #[serde(rename = "type")]
    pub type_url: String,
    /// The HTTP status code [RFC7231, Section 6](https://tools.ietf.org/html/rfc7231#section-6)
    /// generated by the origin server for this occurrence of the problem.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub status: Option<u16>,
    /// A short, human-readable summary of the problem
    /// type. It SHOULD NOT change from occurrence to occurrence of the
    /// problem, except for purposes of localization (e.g., using
    /// proactive content negotiation;
    /// see [RFC7231, Section 3.4](https://tools.ietf.org/html/rfc7231#section-3.4).
    #[serde(skip_serializing_if = "Option::is_none")]
    pub title: Option<String>,
    /// A human-readable explanation specific to this
    /// occurrence of the problem.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub detail: Option<String>,
    /// A URI reference that identifies the specific
    /// occurrence of the problem.  It may or may not yield further
    /// information if dereferenced.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub instance: Option<String>,
}

impl HttpApiProblem {
    /// Creates a new instance with the given `type_url`.
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p = HttpApiProblem::new("http://example.com/my/error");
    ///
    /// assert_eq!("http://example.com/my/error", p.type_url);
    /// assert_eq!(None, p.status);
    /// assert_eq!(None, p.title);
    /// assert_eq!(None, p.detail);
    /// assert_eq!(None, p.instance);
    /// ```
    pub fn new<T: Into<String>>(type_url: T) -> HttpApiProblem {
        HttpApiProblem {
            type_url: type_url.into(),
            status: None,
            title: None,
            detail: None,
            instance: None,
        }
    }

    /// Creates a new instance with the `type_url` derived from the `status`.
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p = HttpApiProblem::with_type_from_status(503);
    ///
    /// assert_eq!("https://httpstatuses.com/503", p.type_url);
    /// assert_eq!(Some(503), p.status);
    /// assert_eq!(None, p.title);
    /// assert_eq!(None, p.detail);
    /// assert_eq!(None, p.instance);
    /// ```
    pub fn with_type_from_status(status: u16) -> HttpApiProblem {
        HttpApiProblem {
            type_url: format!("https://httpstatuses.com/{}", status),
            status: Some(status),
            title: None,
            detail: None,
            instance: None,
        }
    }

    /// Creates a new instance with `type_url` and `title` derived from `status`.
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p = HttpApiProblem::with_type_and_title_from_status(428);
    ///
    /// assert_eq!("https://httpstatuses.com/428", p.type_url);
    /// assert_eq!(Some(428), p.status);
    /// assert_eq!(Some("Precondition Required".to_string()), p.title);
    /// assert_eq!(None, p.detail);
    /// assert_eq!(None, p.instance);
    /// ```
    pub fn with_type_and_title_from_status(status: u16) -> HttpApiProblem {
        HttpApiProblem {
            type_url: format!("https://httpstatuses.com/{}", status),
            status: Some(status),
            title: Some(title_from_status(status)),
            detail: None,
            instance: None,
        }
    }

    /// Creates a new instance with `type_url` set and `title` derived from `status`.
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p = HttpApiProblem::with_title_from_status("http://example.com/my/error", 404);
    ///
    /// assert_eq!("http://example.com/my/error", p.type_url);
    /// assert_eq!(Some(404), p.status);
    /// assert_eq!(Some("Not Found".to_string()), p.title);
    /// assert_eq!(None, p.detail);
    /// assert_eq!(None, p.instance);
    /// ```
    pub fn with_title_from_status<T: Into<String>>(type_url: T, status: u16) -> HttpApiProblem {
        HttpApiProblem {
            type_url: type_url.into(),
            status: Some(status),
            title: Some(title_from_status(status)),
            detail: None,
            instance: None,
        }
    }

    /// Sets the `type_url`
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p = 
    ///     HttpApiProblem::new("http://example.com/my/error")
    ///     .set_type_url("http://example.com/my/real_error");
    ///
    /// assert_eq!("http://example.com/my/real_error", p.type_url);
    /// assert_eq!(None, p.status);
    /// assert_eq!(None, p.title);
    /// assert_eq!(None, p.detail);
    /// assert_eq!(None, p.instance);
    /// ```
    pub fn set_type_url<T: Into<String>>(self, type_url: T) -> HttpApiProblem {
        let mut s = self;
        s.type_url = type_url.into();
        s
    }
    

    /// Sets the `status`
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p = HttpApiProblem::new("http://example.com/my/error").set_status(404);
    ///
    /// assert_eq!("http://example.com/my/error", p.type_url);
    /// assert_eq!(Some(404), p.status);
    /// assert_eq!(None, p.title);
    /// assert_eq!(None, p.detail);
    /// assert_eq!(None, p.instance);
    /// ```
    pub fn set_status(self, status: u16) -> HttpApiProblem {
        let mut s = self;
        s.status = Some(status);
        s
    }

    /// Sets the `title`
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p = HttpApiProblem::new("http://example.com/my/error").set_title("an error");
    ///
    /// assert_eq!("http://example.com/my/error", p.type_url);
    /// assert_eq!(None, p.status);
    /// assert_eq!(Some("an error".to_string()), p.title);
    /// assert_eq!(None, p.detail);
    /// assert_eq!(None, p.instance);
    /// ```
    pub fn set_title<T: Into<String>>(self, title: T) -> HttpApiProblem {
        let mut s = self;
        s.title = Some(title.into());
        s
    }

    /// Sets the `detail`
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p =
    ///     HttpApiProblem::new("http://example.com/my/error")
    ///     .set_detail("a detailed description");
    ///
    /// assert_eq!("http://example.com/my/error", p.type_url);
    /// assert_eq!(None, p.status);
    /// assert_eq!(None, p.title);
    /// assert_eq!(Some("a detailed description".to_string()), p.detail);
    /// assert_eq!(None, p.instance);
    /// ```
    pub fn set_detail<T: Into<String>>(self, detail: T) -> HttpApiProblem {
        let mut s = self;
        s.detail = Some(detail.into());
        s
    }

    /// Sets the `instance`
    ///
    /// #Example
    ///
    /// ```rust
    /// use http_api_problem::*;
    ///
    /// let p =
    ///     HttpApiProblem::new("http://example.com/my/error")
    ///     .set_instance("/account/1234/withdraw");
    ///
    /// assert_eq!("http://example.com/my/error", p.type_url);
    /// assert_eq!(None, p.status);
    /// assert_eq!(None, p.title);
    /// assert_eq!(None, p.detail);
    /// assert_eq!(Some("/account/1234/withdraw".to_string()), p.instance);
    /// ```
    pub fn set_instance<T: Into<String>>(self, instance: T) -> HttpApiProblem {
        let mut s = self;
        s.instance = Some(instance.into());
        s
    }
}

impl From<u16> for HttpApiProblem {
    fn from(status: u16) -> HttpApiProblem {
        HttpApiProblem::with_type_and_title_from_status(status)
    }
}

fn title_from_status(status: u16) -> String {
    match status {
        400 => "Bad Request".to_string(),
        401 => "Unauthorized".to_string(),
        402 => "Payment Required".to_string(),
        403 => "Forbidden".to_string(),
        404 => "Not Found".to_string(),
        405 => "Method Not Allowed".to_string(),
        406 => "Not Acceptable".to_string(),
        407 => "Proxy Authentication Required".to_string(),
        408 => "Request Timeout".to_string(),
        409 => "Conflict".to_string(),
        410 => "Gone".to_string(),
        411 => "Length Required".to_string(),
        412 => "Precondition Failed".to_string(),
        413 => "Payload Too Large".to_string(),
        414 => "Request-URI Too Long".to_string(),
        415 => "Unsupported Media Type".to_string(),
        416 => "Requested Range Not Satisfiable".to_string(),
        417 => "Expectation Failed".to_string(),
        418 => "I'm a teapot".to_string(),
        421 => "Misdirected Request".to_string(),
        422 => "Unprocessable Entity".to_string(),
        423 => "Locked".to_string(),
        424 => "Failed Dependency".to_string(),
        426 => "Upgrade Required".to_string(),
        428 => "Precondition Required".to_string(),
        429 => "Too Many Requests".to_string(),
        431 => "Request Header Fields Too Large".to_string(),
        444 => "Connection Closed Without Response".to_string(),
        451 => "Unavailable For Legal Reasons".to_string(),
        499 => "Client Closed Request".to_string(),

        500 => "Internal Server Error".to_string(),
        501 => "Not Implemented".to_string(),
        502 => "Bad Gateway".to_string(),
        503 => "Service Unavailable".to_string(),
        504 => "Gateway Timeout".to_string(),
        505 => "HTTP Version Not Supported".to_string(),
        506 => "Variant Also Negotiates".to_string(),
        507 => "Insufficient Storage".to_string(),
        508 => "Loop Detected".to_string(),
        510 => "Not Extended".to_string(),
        511 => "Network Authentication Required".to_string(),
        599 => "Network Connect Timeout Error".to_string(),

        x => {
            if x / 100 == 4 {
                format!("Custom Client Error({})", x)
            } else if x / 100 == 5 {
                format!("Custom Server Error({})", x)
            } else {
                format!("Custom Error({})", x)
            }
        }
    }
}