devdocs-local

#!/usr/bin/env sh
# Select docs from devdocs.io using a fuzzy-finder for display at the CLI
#
# Deps: tidy, xmlstarlet, jq, lynx, fzy, curl, POSIX
# (This uses a few shell scripts from $HOME/bin. Look there for reference.)
#
# Usage:
#
#     devdocs-local download
#     devdocs-local

NAME=$(basename "$0")
TEMP="${TMPDIR-/tmp}/${NAME}.${$}.$(awk \
    'BEGIN {srand(); printf "%d\n", rand() * 10^10}')"

DEVDOCS_DIR="${DEVDOCS_DIR-"${HOME}/tmp/docs/devdocs.io"}"
mkdir -p "$DEVDOCS_DIR"

list () {
    # Find the docs JavaScript and try to extract the slug and mtime values.

    curl -sS https://devdocs.io |
        htmlstar sel -t -v '//_:script[contains(@src, "docs-")]/@src' \
            2>/dev/null |
        xargs printf 'http:%s\n' |
        xargs curl -sS |
        awk '
            /^slug: / {
                match($2, /".*"/)
                slug = substr($2, RSTART + 1, RLENGTH - 2)
            }
            /^mtime: / {
                mtime = substr($2, 1, length($2) - 1)
                print slug, mtime
            }
        '
}

download () {
    # Download the docsets to a deterministic location.

    # TODO: add multiple selection
    list |
        fzy -p 'Choose a docset > ' | {
            while read -r slug mtime; do
                test -n "$slug" || return

                ddir="${DEVDOCS_DIR}/${slug}"

                mkdir -p "$ddir"
                cd "$ddir"

                if [ -r "${ddir}/mtime" ]; then
                    old_mtime=$(< "${ddir}/mtime")

                    if [ "$old_mtime" -ge "$mtime" ]; then
                        printf '%s already installed.\n' "$slug" 1>&2
                        return
                    fi
                fi

                printf '%s\n' "$mtime" > mtime

                curl -sS -o index.json "https://devdocs.io/docs/${slug}/index.json?${mtime}"
                curl -sS -o db.json "https://docs.devdocs.io/${slug}/db.json?${mtime}"
            done;
        }
}

doc () {
    find "$DEVDOCS_DIR" -mindepth 1 -type d -printf '%f\n' |
        fzy -p 'Choose docs > ' | {
            read -r slug
            test -n "$slug" || return

            jq -r '.entries[] | "\(.name) --- \(.path) --- (\(.type))"' \
                "${DEVDOCS_DIR}/${slug}/index.json" |
            fzy -p 'Choose a topic > ' |
            awk -F " --- " '{
                h = index($2, "#")
                if (h == 0) {
                    print $2
                } else {
                    print substr($2, 1, h - 1), substr($2, h)
                }
            }' | {
                read -r dpath frag
                test -n "$dpath" || return

                jq -r ".\"${dpath}\"" \
                    < "${DEVDOCS_DIR}/${slug}/db.json" \
                    > "${TEMP}/index.html"

                lynx -assume_charset=utf-8 \
                    "file://localhost/${TEMP}/index.html${frag}"
            };
        }
}

main () {
    trap '
        excode=$?; trap - EXIT;
        rm -rf '"$TEMP"'
        exit $excode
    ' INT TERM EXIT
    mkdir -p -m 700 "$TEMP"

    if [ $# -eq 0 ]; then
        doc
    else
        cmd=$1
        shift

        "$cmd" "$@"
    fi
}

main "$@"