#!/bin/sh -e

txt2html() {
    # Transform plain-text input into HTML and insert it into the template.
    # Right now this only does some URL transformations.

    # Convert all plain-text links to HTML links (<a href="X">X</a>).
    sed -E "s|([^\"\'\>=])(http[s]?://[^[:space:]\)]*)|\1<a href=\2 target=\"_blank\">\2</a>|g" |
    sed -E "s|^(http[s]?://[^[:space:]\)]*)|<a href=\1>\1</a>|g" |

    # Convert all plain-text links to Gemini links (<a href="X">X</a>).
    sed -E "s|([^\"\'\>=])(gemini://[^[:space:]\)]*)|\1<a href=\2>\2</a>|g" |
    sed -E "s|^(gemini://[^[:space:]\)]*)|<a href=\1>\1</a>|g" |

    # Convert all plain-text links to IRC links (<a href="X">X</a>).
    sed -E "s|([^\"\'\>=])(irc://[^[:space:]\)]*)|\1<a href=\2>\2</a>|g" |
    sed -E "s|^(irc://[^[:space:]\)]*)|<a href=\1>\1</a>|g" |

    # Convert #/words to absolute HTML links.
    # Convert %/words to absolute blog links.
    # Convert @/words to relative HTML links.
    sed -E "s|(#/)([^ \)]*)|\1<a href=/\2>\2</a>|g" |
    sed -E "s|(%/)([^ \)]*)|\1<a href=/blog/\2>\2</a>|g" |
    sed -E "s|(@/)([^ \)]*)|\1<a href=${pp##.}/\2>\2</a>|g" |

    # Convert ~/words to Source Hut URLs.
    # Convert $/words to Source Hut Repo URLs.
    # Conver mail/words to Source Hut Mailing List URLs.
    sed -E "s|(\\~/)([^ \)]*)|\1<a href=$repo_url/~\2>\2</a>|g" |
    sed -E "s|(\\$/)([^ \)]*)|\1<a href=$repo_url/~$sr_ht_user/\2>\2</a>|g" |
    sed -E "s|(\\mail/)([^ \)]*)|\1<a href=$mail_url/~$sr_ht_user/\2>\2</a>|g" |

    # Convert [0-9] into HTML links.
    sed -E "s|^([ -]*)\[([0-9\.]*)\]|\1<span id=\2>[\2]</span>|g" |
    sed -E "s|([^\"#])\[([0-9\.]*)\]|\1[<a class=t href=#\2>\2</a>]|g" |

    # Insert the page into the template.
    sed -E '/%%CONTENT%%/r /dev/stdin' template.html |
    sed -E '/%%CONTENT%%/d' | 
    # Insert the page path into the source URL.
    sed -E "s	%%TITLE%%	$title	"
}

page() {
    pp=${page%/*} title=${page##*/} title=${title%%.txt}

    mkdir -p "docs/$pp"

    # If the title is index.txt, set it to the parent directory name.
    # Example: /wiki/index.txt (index) -> (wiki).
    case $title in index) title=${pp##*/} ;; esac
    case $title in .)     title=home ;; esac

    # GENERATION STEP.
    case $page in
        *.txt)
            txt2html < "site/$page" > "docs/${page%%.txt}.html"
        ;;

        # Copy over any non-txt files.
        *)
            cp -f "site/$page" "docs/$page"
        ;;
    esac

    # POST-GENERATION STEP.
    case $page in
        # Hardlink all .txt files to the docs/ directory.
        *.txt) ln -f "site/$page" "docs/$page" ;;
    esac
}

main() {
    repo_url=https://git.sr.ht
    mail_url=https://lists.sr.ht
    sr_ht_user=ctb

    rm -rf docs
    mkdir -p docs

    (cd site && find . -type f) | while read -r page; do
        printf '%s\n' "CC $page"
        page "$page"
    done
}

main "$@"