#!/bin/sh
# This is the void linux documentation browser

[ "$DEBUG" ] && set -x
# turn on errors and noglob
set -fe

# document to open
VOIDDOC=
# terms to search for
TERMS=
# versions to try
_html=1
_md=1
_roff=1
_pdf=

usage() {
    cat <<EOF
Welcome to the Void Linux documentation browser!

Usage: $0 [options] [search terms]

Options:
-h, --help: show this help text
-b: only try to display the HTML version
-m: only try to display the Markdown version
-r: only try to display the roff (mandoc) version
-p: open the PDF version
-s: only display search results
EOF

    exit 0
}

while [ $# -gt 0 ]; do
    case $1 in
        -h|--help) usage ;;
        -b) _html=1 ; _md= ; _roff= ;;
        -m) _html= ; _md=1 ; _roff= ;;
        -r) _html= ; _md= ; _roff=1 ;;
        -p) _pdf=1 ;;
        -s) _search=1 ;;
        *)
            if [ "$TERMS" ]; then
                TERMS="$TERMS -and -iwholename *$1*"
            else
                TERMS="-iwholename *$1*"
            fi
            ;;
    esac
    shift
done

: "${DOCS:=@PREFIX@/share/doc/void}"

if [ "$_pdf" ]; then
    PDF="$DOCS/handbook.pdf"
    if [ -n "$PDF_VIEWER" ] && command -v "$PDF_VIEWER" >dev/null; then
        exec $PDF_VIEWER $PDF
    elif command -v xdg-open >/dev/null; then
        exec xdg-open $PDF
    elif command -v run-mailcap >/dev/null; then
        exec run-mailcap --action=view $PDF
    else
        for cmd in zathura okular evince
        do
            if command -v $cmd >/dev/null; then
                exec $cmd $PDF
            fi
        done
    fi
fi

# creates the appropriate path
find_page() {
    case $1 in
        html) VOIDDOC="$DOCS/html/$2.html" ;;
        md) VOIDDOC="$DOCS/markdown/$2.md" ;;
        man) VOIDDOC="$DOCS/mandoc/$2.7" ;;
    esac

    if [ -f "$VOIDDOC" ]; then
        echo "$VOIDDOC"
    else
        echo "couldn't find file" >&2
        return 1
    fi
}

# knows how to open a certain page
open_page() {
    if [ "$_html" ]; then
        if [ -n "$BROWSER" ] && command -v $BROWSER >/dev/null; then
            page=$(find_page html $1)
            exec $BROWSER $page
        fi

        # check if wayland or X session
        if [ -n "$WAYLAND_DISPLAY" -o -n "$DISPLAY" ] && command -v xdg-open >/dev/null; then
            page=$(find_page html $1)
            exec xdg-open $page
        fi

        if command -v run-mailcap >/dev/null; then
            exec run-mailcap --action=view $PDF
        fi

        # if a browser or xdg-open weren't available, we can try other stuff

        # cli browser
        for viewer in lynx w3m links
        do
            if command -v $viewer >/dev/null; then
                page=$(find_page html $1)
                exec $viewer $page
            fi
        done
    fi

    if [ "$_md" ]; then
        # markdown processor
        _viewer=
        if command -v mdcat >/dev/null; then
            _viewer=mdcat
        elif command -v lowdown >/dev/null; then
            _viewer="lowdown -Tterm"
        elif command -v glow >/dev/null; then
            _viewer=glow
        fi
        if [ "$_viewer" ]; then
            page=$(find_page md $1)
            $_viewer $page | less -R
            exit
        fi
    fi

    if [ "$_roff" ]; then
        # otherwise go for the man page
        page=$(find_page man $1)
        exec man -l $page
    fi

    echo "Couldn't find a program to display the documentation."
    return 1
}

search_page() {
    file="$(find $DOCS/markdown -type f $1 -printf "%P\n")"
    [ -z "$file" ] && exit 1

    if [ "$_search" ]; then
        echo "$file"
        return 0
    fi

    _pager="head -1"
    if command -v fzf >/dev/null; then
        _pager=fzf
    elif command -v sk >/dev/null; then
        _pager=sk
    elif command -v pick >/dev/null; then
        _pager=pick
    fi

    if [ $(IFS=' '; echo $file | wc -l) -gt 1 ]; then
        file="$(echo "$file" | $_pager)"
    fi
    file="${file%.md}"
    echo "$file"
}

page=about/index
[ "$TERMS" ] && page="$(search_page "$TERMS")"

if [ "$_search" ]; then
    echo "$page"
    exit 0
fi

open_page "$page"