maple-core-macro 0.4.2

use proc_macro2::TokenStream;
use quote::{quote, quote_spanned, ToTokens};
use syn::ext::IdentExt;
use syn::parse::{Parse, ParseStream, Result};
use syn::spanned::Spanned;
use syn::{token, Ident, Token};

use crate::attributes::{AttributeList, AttributeType};
use crate::children::Children;
use crate::text::Text;
use crate::HtmlTree;

/// Represents a html element with all its attributes and properties (e.g. `p(class="text")`).
pub(crate) struct Element {
    tag_name: TagName,
    attributes: Option<AttributeList>,
    children: Option<Children>,
}

impl Parse for Element {
    fn parse(input: ParseStream) -> Result<Self> {
        let tag_name = input.parse()?;

        let attributes = if input.peek(token::Paren) {
            Some(input.parse()?)
        } else {
            None
        };

        let children = if input.peek(token::Brace) {
            Some(input.parse()?)
        } else {
            None
        };

        Ok(Self {
            tag_name,
            attributes,
            children,
        })
    }
}

impl ToTokens for Element {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        let Element {
            tag_name,
            attributes,
            children,
        } = self;

        let mut set_attributes = Vec::new();
        let mut set_event_listeners = Vec::new();
        let mut set_noderefs = Vec::new();
        if let Some(attributes) = attributes {
            for attribute in &attributes.attributes {
                let expr = &attribute.expr;
                let expr_span = expr.span();

                match &attribute.ty {
                    AttributeType::DomAttribute { name } => {
                        set_attributes.push(quote_spanned! { expr_span=>
                                ::maple_core::internal::attr(::std::convert::AsRef::as_ref(&element), #name, ::std::boxed::Box::new(move || ::std::format!("{}", #expr)));
                            });
                    }
                    AttributeType::Event { name } => {
                        set_event_listeners.push(quote_spanned! { expr_span=>
                            ::maple_core::internal::event(::std::convert::AsRef::as_ref(&element), #name, ::std::boxed::Box::new(#expr));
                        });
                    }
                    AttributeType::Ref => {
                        set_noderefs.push(quote_spanned! { expr_span=>
                            ::maple_core::internal::set_noderef(&element, #expr);
                        });
                    }
                }
            }
        }

        let mut append_children = Vec::new();
        if let Some(children) = children {
            for child in &children.body {
                let quoted = match child {
                    HtmlTree::Component(component) => quote_spanned! { component.span()=>
                        ::maple_core::internal::append(&element, &#component);
                    },
                    HtmlTree::Element(element) => quote_spanned! { element.span()=>
                        ::maple_core::internal::append(&element, &#element);
                    },
                    HtmlTree::Text(text) => match text {
                        Text::Text(_) => {
                            quote_spanned! { text.span()=>
                                ::maple_core::internal::append_static_text(&element, &#text);
                            }
                        }
                        Text::Splice(_, _) => {
                            quote_spanned! { text.span()=>
                                ::maple_core::internal::append_render(&element, ::std::boxed::Box::new(move || {
                                    ::std::boxed::Box::new(#text)
                                }));
                            }
                        }
                    },
                };

                append_children.push(quoted);
            }
        }

        let quoted = quote! {{
            let element = #tag_name;
            #(#set_attributes)*
            #(#set_event_listeners)*
            #(#set_noderefs)*
            #(#append_children)*
            element
        }};
        tokens.extend(quoted);
    }
}

/// Represents a html element tag (e.g. `div`, `custom-element` etc...).
pub struct TagName {
    tag: Ident,
    extended: Vec<(Token![-], Ident)>,
}

impl Parse for TagName {
    fn parse(input: ParseStream) -> Result<Self> {
        let tag = input.call(Ident::parse_any)?;
        let mut extended = Vec::new();
        while input.peek(Token![-]) {
            extended.push((input.parse()?, input.parse()?));
        }

        Ok(Self { tag, extended })
    }
}

impl ToTokens for TagName {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        let TagName { tag, extended } = self;

        let mut tag_str = tag.to_string();
        for (_, ident) in extended {
            tag_str.push_str(&format!("-{}", ident));
        }

        let quoted = quote! {
            ::maple_core::internal::element(#tag_str)
        };

        tokens.extend(quoted);
    }
}