//! Virtual Node Support
//!
//! VNodes represent lazily-constructed VDom trees that support diffing and event handlers. These VNodes should be *very*
//! cheap and *very* fast to construct - building a full tree should be quick.

use std::fmt::{Debug, Formatter};

mod arbitrary_value;
mod component;
mod element;
mod factory;
mod fragment;
mod placeholder;
mod suspense;
mod template;
mod text;

pub use arbitrary_value::*;
pub use component::*;
pub use element::*;
pub use factory::*;
pub use fragment::*;
pub use suspense::*;
pub use template::*;
pub use text::*;

use self::placeholder::VPlaceholder;

/// A composable "VirtualNode" to declare a User Interface in the Dioxus VirtualDOM.
///
/// VNodes are designed to be lightweight and used with with a bump allocator. To create a VNode, you can use either of:
///
/// - the `rsx!` macro
/// - the [`NodeFactory`] API
pub enum VNode<'src> {
    /// Text VNodes are simply bump-allocated (or static) string slices
    ///
    /// # Example
    ///
    /// ```rust, ignore
    /// let mut vdom = VirtualDom::new();
    /// let node = vdom.render_vnode(rsx!( "hello" ));
    ///
    /// if let VNode::Text(vtext) = node {
    ///     assert_eq!(vtext.text, "hello");
    ///     assert_eq!(vtext.dom_id.get(), None);
    ///     assert_eq!(vtext.is_static, true);
    /// }
    /// ```
    Text(&'src VText<'src>),

    /// Element VNodes are VNodes that may contain attributes, listeners, a key, a tag, and children.
    ///
    /// # Example
    ///
    /// ```rust, ignore
    /// let mut vdom = VirtualDom::new();
    ///
    /// let node = vdom.render_vnode(rsx!{
    ///     div {
    ///         key: "a",
    ///         onclick: |e| log::info!("clicked"),
    ///         hidden: "true",
    ///         style: { background_color: "red" },
    ///         "hello"
    ///     }
    /// });
    ///
    /// if let VNode::Element(velement) = node {
    ///     assert_eq!(velement.tag_name, "div");
    ///     assert_eq!(velement.namespace, None);
    ///     assert_eq!(velement.key, Some("a"));
    /// }
    /// ```
    Element(&'src VElement<'src>),

    /// Fragment nodes may contain many VNodes without a single root.
    ///
    /// # Example
    ///
    /// ```rust, ignore
    /// rsx!{
    ///     a {}
    ///     link {}
    ///     style {}
    ///     "asd"
    ///     Example {}
    /// }
    /// ```
    Fragment(&'src VFragment<'src>),

    /// Component nodes represent a mounted component with props, children, and a key.
    ///
    /// # Example
    ///
    /// ```rust, ignore
    /// fn Example(cx: Scope) -> Element {
    ///     ...
    /// }
    ///
    /// let mut vdom = VirtualDom::new();
    ///
    /// let node = vdom.render_vnode(rsx!( Example {} ));
    ///
    /// if let VNode::Component(vcomp) = node {
    ///     assert_eq!(vcomp.user_fc, Example as *const ());
    /// }
    /// ```
    Component(&'src VComponent<'src>),

    /// Templetes ase generated by the rsx macro to eleminate diffing static nodes.
    ///
    ///
    ///
    ///
    ///
    ///
    Template(&'src VTemplate<'src>),
}

/// An Element's unique identifier.
///
/// `ElementId` is a `usize` that is unique across the entire VirtualDOM - but not unique across time. If a component is
/// unmounted, then the `ElementId` will be reused for a new component.
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(feature = "serialize", serde(transparent))]
pub struct ElementId(pub usize);

impl<'src> VNode<'src> {
    /// Get the VNode's "key" used in the keyed diffing algorithm.
    pub fn key(&self) -> Option<&'src str> {
        match &self {
            VNode::Element(el) => el.key,
            VNode::Component(c) => c.key,
            VNode::Fragment(f) => f.key,
            VNode::Template(t) => t.key,
            VNode::Text(_t) => None,
        }
    }

    /// Get the ElementID of the mounted VNode.
    ///
    /// Panics if the mounted ID is None or if the VNode is not represented by a single Element.
    pub fn mounted_id(&self) -> ElementId {
        self.try_mounted_id().unwrap()
    }

    /// Try to get the ElementID of the mounted VNode.
    ///
    /// Returns None if the VNode is not mounted, or if the VNode cannot be presented by a mounted ID (Fragment/Component)
    pub fn try_mounted_id(&self) -> Option<ElementId> {
        match &self {
            VNode::Text(el) => el.id.get(),
            VNode::Element(el) => el.id.get(),
            VNode::Fragment(_) => None,
            VNode::Component(_) => None,
            VNode::Template(_) => None,
        }
    }

    // Create an "owned" version of the vnode.
    pub(crate) fn decouple(&self) -> VNode<'src> {
        match *self {
            VNode::Text(t) => VNode::Text(t),
            VNode::Element(e) => VNode::Element(e),
            VNode::Component(c) => VNode::Component(c),
            VNode::Fragment(f) => VNode::Fragment(f),
            VNode::Template(t) => VNode::Template(t),
        }
    }
}

impl Debug for VNode<'_> {
    fn fmt(&self, s: &mut Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
        match &self {
            VNode::Element(el) => s
                .debug_struct("VNode::Element")
                .field("name", &el.tag)
                .field("key", &el.key)
                .field("attrs", &el.attributes)
                .field("children", &el.children)
                .field("id", &el.id)
                .finish(),
            VNode::Text(t) => s
                .debug_struct("VNode::Text")
                .field("text", &t.text)
                .field("id", &t.id)
                .finish(),
            VNode::Fragment(frag) => s
                .debug_struct("VNode::Fragment")
                .field("children", &frag.children)
                .finish(),
            VNode::Component(comp) => s
                .debug_struct("VNode::Component")
                .field("name", &comp.fn_name)
                .field("fnptr", &comp.user_fc)
                .field("key", &comp.key)
                .field("scope", &comp.scope)
                .finish(),
            VNode::Template(temp) => s
                .debug_struct("VNode::Templates")
                .field("template_id", &temp.template.id)
                .finish(),
        }
    }
}