/*
 * This file is part of ActivityStreams Types.
 *
 * Copyright © 2018 Riley Trautman
 *
 * ActivityStreams Types is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ActivityStreams Types is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ActivityStreams Types.  If not, see <http://www.gnu.org/licenses/>.
 */

//! Namespace for properties of standard link types
//!
//! To use these properties in your own types, you can flatten them into your struct with serde:
//!
//! ```rust
//! extern crate activitystreams_traits;
//! extern crate activitystreams_types;
//! extern crate serde;
//! #[macro_use]
//! extern crate serde_derive;
//!
//! use activitystreams_traits::Link;
//! use activitystreams_types::link::properties::LinkProperties;
//!
//! #[derive(Clone, Debug, Serialize, Deserialize)]
//! #[serde(rename_all = "camelCase")]
//! pub struct MyLink {
//!     #[serde(rename = "type")]
//!     pub kind: String,
//!
//!     /// Define a require property for the MyLink type
//!     pub my_property: String,
//!
//!     #[serde(flatten)]
//!     pub link_properties: LinkProperties,
//! }
//!
//! impl Link for MyLink {}
//! #
//! # fn main() {}
//! ```

use activitystreams_traits::{Error, Link, Object, Result};
use mime;
use serde_json;

/// Define all the properties of the Object base type as described by the Activity Streams
/// vocabulary.
///
/// The properties of the `Link` object are not the properties of the referenced resource, but are
/// provided as hints for rendering agents to understand how to make use of the resource. For
/// example, height and width might represent the desired rendered size of a referenced image,
/// rather than the actual pixel dimensions of the referenced image.
///
/// The target URI of the Link is expressed using the required href property.
///
/// For example, all Objects can contain an image property whose value describes a graphical
/// representation of the containing object. This property will typically be used to provide the URL
/// to an image (e.g. JPEG, GIF or PNG) resource that can be displayed to the user. Any given object
/// might have multiple such visual representations -- multiple screenshots, for instance, or the
/// same image at different resolutions. In Activity Streams 2.0, there are essentially three ways
/// of describing such references.
#[derive(Clone, Debug, Default, Deserialize, Serialize, Properties)]
#[serde(rename_all = "camelCase")]
pub struct LinkProperties {
    // TODO: IRI type
    /// Provides the globally unique identifier for an Object or Link.
    ///
    /// The `id` property is expressed as an absolute IRI in the spec, but for now is represented
    /// as a string.
    ///
    /// - Range: `anyUri`
    /// - Functional: true
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(concrete(String), functional)]
    pub id: Option<serde_json::Value>,

    /// Identifies the context within which the object exists or an activity was performed.
    ///
    /// The notion of "context" used is intentionally vague. The intended function is to serve as a
    /// means of grouping objects and activities that share a common originating context or purpose.
    /// An example could be all activities relating to a common project or event.
    ///
    /// - Range: `Object` | `Link`
    /// - Functional: false
    #[serde(skip_serializing_if = "Option::is_none", rename = "@context")]
    #[activitystreams(ab(Object, Link))]
    pub context: Option<serde_json::Value>,

    // TODO: rdf:langString
    /// A simple, human-readable, plain-text name for the object.
    ///
    /// HTML markup MUST NOT be included. The name MAY be expressed using multiple language-tagged
    /// values.
    ///
    /// - Range: `xsd:string` | `rdf:langString`
    /// - Functional: false
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(concrete(String))]
    pub name: Option<serde_json::Value>,

    /// The target resource pointed to by a Link.
    ///
    /// - Range: `xsd:anyUri`
    /// - Functional: true
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(concrete(String), functional)]
    pub href: Option<serde_json::Value>,

    // TODO: lang enum
    /// Hints as to the language used by the target resource.
    ///
    /// Value MUST be a [[BCP47](https://tools.ietf.org/html/bcp47)]
    /// Language-Tag.
    ///
    /// - Range: [[BCP47](https://tools.ietf.org/html/bcp47)] Language
    /// Tag
    /// - Functional: true
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(concrete(String), functional)]
    pub hreflang: Option<serde_json::Value>,

    /// When used on a `Link`, identifies the MIME media type of the referenced resource.
    ///
    /// If not specified, the content property is assumed to contain text/html content.
    ///
    /// - Range: `Mime Media Type`
    /// - Functional: true
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(concrete(String), functional)]
    pub media_type: Option<serde_json::Value>,

    /// A link relation associated with a Link.
    ///
    /// The value MUST conform to both the
    /// [[HTML5](https://www.w3.org/TR/html5/)] and [[RFC5988](https://tools.ietf.org/html/rfc5988)]
    /// "link relation" definitions.
    ///
    /// In the [[HTML5](https://www.w3.org/TR/html5/)], any string
    /// not containing the "space" U+0020, "tab" (U+0009), "LF" (U+000A), "FF" (U+000C), "CR"
    /// (U+000D) or "," (U+002C) characters can be used as a valid link relation.
    ///
    /// - Range:
    ///     [[RFC5988](https://tools.ietf.org/html/rfc5988)] or
    ///     [[HTML5](https://www.w3.org/TR/html5/)] Link Relation
    /// - Functional: false
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(concrete(String))]
    pub rel: Option<serde_json::Value>,

    /// On a `Link`, specifies a hint as to the rendering height in device-independent pixels of the
    /// linked resource.
    ///
    /// - Range: `xsd:nonNegativeInteger`
    /// - Functional: true
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(concrete(u64), functional)]
    pub height: Option<serde_json::Value>,

    /// On a `Link`, specifies a hint as to the rendering width in device-independent pixels of the
    /// linked resource.
    ///
    /// - Range: `xsd:nonNegativeInteger`
    /// - Functional: true
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(concrete(u64), functional)]
    pub width: Option<serde_json::Value>,

    /// Identifies an entity that provides a preview of this object.
    ///
    /// - Range: `Object` | `Link`
    /// - Functional: false
    #[serde(skip_serializing_if = "Option::is_none")]
    #[activitystreams(ab(Object, Link))]
    pub preview: Option<serde_json::Value>,
}

impl LinkProperties {
    /// Fetch a typed `Mime` struct from the `media_type` field.
    pub fn media_type(&self) -> Result<mime::Mime> {
        self.media_type_string()
            .and_then(|s| s.parse().map_err(|_| Error::Deserialize))
    }
}