{-# LANGUAGE OverloadedStrings, QuasiQuotes #-}
module Nirum.Docs.Html (render, renderInline, renderInlines, renderBlock) where

import qualified Data.Text as T
import Text.InterpolatedString.Perl6 (qq)

import Nirum.Docs

renderInline :: Inline -> Html
renderInline (Text t) = escape t
renderInline SoftLineBreak = "\n"
renderInline HardLineBreak = "<br>"
renderInline (HtmlInline html) = html
renderInline (Code code') = [qq|<code>{escape code'}</code>|]
renderInline (Emphasis inlines) = [qq|<em>{renderInlines inlines}</em>|]
renderInline (Strong inlines) = [qq|<strong>{renderInlines inlines}</strong>|]
renderInline (Link url title inlines) =
    let body = renderInlines inlines
    in
        if T.null title
            then [qq|<a href="{escape url}">$body</a>|]
            else [qq|<a href="{escape url}" title="{escape title}">$body</a>|]
renderInline (Image url title) =
    if T.null title
        then [qq|<img src="{escape url}">|]
        else [qq|<img src="{escape url}" title="{escape title}">|]

escape :: T.Text -> Html
escape = T.concatMap escapeChar

escapeChar :: Char -> Html
escapeChar '&' = "&amp;"
escapeChar '"' = "&quot;"
escapeChar '<' = "&lt;"
escapeChar '>' = "&gt;"
escapeChar c = T.singleton c

renderInlines :: [Inline] -> Html
renderInlines = T.concat . map renderInline

renderBlock :: Block -> Html
renderBlock (Document blocks) = renderBlocks blocks `T.snoc` '\n'
renderBlock ThematicBreak = "<hr>"
renderBlock (Paragraph inlines) = [qq|<p>{renderInlines inlines}</p>|]
renderBlock (BlockQuote blocks) =
    [qq|<blockquote>{renderBlocks blocks}</blockquotes>|]
renderBlock (HtmlBlock html) = html
renderBlock (CodeBlock lang code') =
    if T.null lang
    then [qq|<pre><code>$code'</code></pre>|]
    else [qq|<pre><code class="language-$lang">$code'</code></pre>|]
renderBlock (Heading level inlines) =
    let lv = headingLevelInt level
    in [qq|<h$lv>{renderInlines inlines}</h$lv>|]
renderBlock (List listType itemList) =
    let liList = case itemList of
                     TightItemList items ->
                         [ [qq|<li>{renderInlines item}</li>|]
                         | item <- items
                         ]
                     LooseItemList items ->
                         [ [qq|<li>{renderBlocks item}</li>|]
                         | item <- items
                         ]
        tag = case listType of
                  BulletList -> "ul" :: T.Text
                  OrderedList { startNumber = 1 } -> "ol"
                  OrderedList { startNumber = startNumber' } ->
                      [qq|ol start="$startNumber'"|]
        nl = '\n'
        liListT = T.intercalate "\n" liList
    in [qq|<$tag>$nl$liListT$nl</$tag>|]

renderBlocks :: [Block] -> Html
renderBlocks = T.intercalate "\n" . map renderBlock

render :: Block -> Html
render = renderBlock