//! HTML5 tokenizer and tree builder.
//!
//! Implements the WHATWG HTML5 tokenizer state machine (§13.2.5)
//! and a simplified tree builder for constructing DOM trees from tokens.

mod entities;
pub mod speculative;
mod tokenizer;
mod tree_builder;

pub use tokenizer::{ParseError, Tokenizer};
pub use tree_builder::{parse_html, TreeBuilder};

/// A token emitted by the HTML tokenizer.
#[derive(Debug, Clone, PartialEq)]
pub enum Token {
    /// `<!DOCTYPE name public_id system_id>`
    Doctype {
        name: Option<String>,
        public_id: Option<String>,
        system_id: Option<String>,
        force_quirks: bool,
    },
    /// `<tag attr="val">`
    StartTag {
        name: String,
        attributes: Vec<(String, String)>,
        self_closing: bool,
    },
    /// `</tag>`
    EndTag { name: String },
    /// Character data (may be coalesced).
    Character(String),
    /// `<!-- comment -->`
    Comment(String),
    /// End of file.
    Eof,
}

/// Tokenize an HTML input string into a sequence of tokens.
///
/// Runs the HTML5 tokenizer state machine and returns all emitted tokens
/// (excluding Eof). Adjacent Character tokens are coalesced.
pub fn tokenize(input: &str) -> Vec<Token> {
    let mut tok = Tokenizer::new(input);
    let mut tokens = Vec::new();
    loop {
        let token = tok.next_token();
        if let Token::StartTag { name, .. } = &token {
            // Mirror tree-construction state switching so script/style/title
            // content tokenizes correctly when the caller drives the
            // tokenizer through this convenience wrapper.
            match name.as_str() {
                "script" => tok.switch_to_script_data(),
                "style" | "iframe" | "xmp" | "noembed" | "noframes" | "noscript" => {
                    tok.switch_to_rawtext();
                }
                "title" | "textarea" => tok.switch_to_rcdata(),
                _ => {}
            }
        }
        match token {
            Token::Eof => break,
            Token::Character(ref s) => {
                // Coalesce adjacent character tokens.
                if let Some(Token::Character(ref mut prev)) = tokens.last_mut() {
                    prev.push_str(s);
                } else {
                    tokens.push(token);
                }
            }
            _ => tokens.push(token),
        }
    }
    tokens
}