use crate::html_element::HtmlElement;
use crate::markdown_writer::{HandleTag, MarkdownWriter, StartTagOutcome};

pub struct ParagraphHandler;

impl HandleTag for ParagraphHandler {
    fn should_handle(&self, _tag: &str) -> bool {
        true
    }

    fn handle_tag_start(
        &mut self,
        tag: &HtmlElement,
        writer: &mut MarkdownWriter,
    ) -> StartTagOutcome {
        if tag.is_inline() && writer.is_inside("p") {
            if let Some(parent) = writer.current_element_stack().iter().last() {
                if !parent.is_inline() {
                    if !(writer.markdown.ends_with(' ') || writer.markdown.ends_with('\n')) {
                        writer.push_str(" ");
                    }
                }
            }
        }

        match tag.tag.as_str() {
            "p" => writer.push_blank_line(),
            _ => {}
        }

        StartTagOutcome::Continue
    }
}

pub struct HeadingHandler;

impl HandleTag for HeadingHandler {
    fn should_handle(&self, tag: &str) -> bool {
        match tag {
            "h1" | "h2" | "h3" | "h4" | "h5" | "h6" => true,
            _ => false,
        }
    }

    fn handle_tag_start(
        &mut self,
        tag: &HtmlElement,
        writer: &mut MarkdownWriter,
    ) -> StartTagOutcome {
        match tag.tag.as_str() {
            "h1" => writer.push_str("\n\n# "),
            "h2" => writer.push_str("\n\n## "),
            "h3" => writer.push_str("\n\n### "),
            "h4" => writer.push_str("\n\n#### "),
            "h5" => writer.push_str("\n\n##### "),
            "h6" => writer.push_str("\n\n###### "),
            _ => {}
        }

        StartTagOutcome::Continue
    }

    fn handle_tag_end(&mut self, tag: &HtmlElement, writer: &mut MarkdownWriter) {
        match tag.tag.as_str() {
            "h1" | "h2" | "h3" | "h4" | "h5" | "h6" => writer.push_blank_line(),
            _ => {}
        }
    }
}

pub struct ListHandler;

impl HandleTag for ListHandler {
    fn should_handle(&self, tag: &str) -> bool {
        match tag {
            "ul" | "ol" | "li" => true,
            _ => false,
        }
    }

    fn handle_tag_start(
        &mut self,
        tag: &HtmlElement,
        writer: &mut MarkdownWriter,
    ) -> StartTagOutcome {
        match tag.tag.as_str() {
            "ul" | "ol" => writer.push_newline(),
            "li" => writer.push_str("- "),
            _ => {}
        }

        StartTagOutcome::Continue
    }

    fn handle_tag_end(&mut self, tag: &HtmlElement, writer: &mut MarkdownWriter) {
        match tag.tag.as_str() {
            "ul" | "ol" => writer.push_newline(),
            "li" => writer.push_newline(),
            _ => {}
        }
    }
}

pub struct StyledTextHandler;

impl HandleTag for StyledTextHandler {
    fn should_handle(&self, tag: &str) -> bool {
        match tag {
            "strong" | "em" => true,
            _ => false,
        }
    }

    fn handle_tag_start(
        &mut self,
        tag: &HtmlElement,
        writer: &mut MarkdownWriter,
    ) -> StartTagOutcome {
        match tag.tag.as_str() {
            "strong" => writer.push_str("**"),
            "em" => writer.push_str("_"),
            _ => {}
        }

        StartTagOutcome::Continue
    }

    fn handle_tag_end(&mut self, tag: &HtmlElement, writer: &mut MarkdownWriter) {
        match tag.tag.as_str() {
            "strong" => writer.push_str("**"),
            "em" => writer.push_str("_"),
            _ => {}
        }
    }
}