#!/bin/bash
# Run a command, or search the web for it.
#
#   Enter      run it if it is an executable, otherwise search for it
#   Alt+Enter  always search, even if it looks like a command
#
# The second one exists because deciding by "is the first word a binary?" gets
# it wrong for ordinary phrases: test, who, which, sort, time and file are all
# real executables. Alt+Enter is bound to fuzzel's custom-1, which is dmenu-only
# and exits with code 10 (see [key-bindings] in fuzzel.ini).

browser_app_id="google-chrome"
search_url="https://duckduckgo.com/?q="

# Executables in PATH. Deliberately not `compgen -c`: that also lists shell
# builtins and keywords (cd, alias, if, ...), which `command -v` reports as
# found but `exec` cannot run.
list_path_bins() {
    local IFS=: dir file
    for dir in $PATH; do
        [[ -d $dir ]] || continue
        for file in "$dir"/*; do
            [[ -f $file && -x $file ]] && printf '%s\n' "${file##*/}"
        done
    done | sort -u
}

search_web() {
    local query
    query=$(jq -rn --arg q "$1" '$q|@uri')
    xdg-open "$search_url$query" &

    # Wait for the browser window instead of guessing at a fixed sleep: a cold
    # start takes well over half a second, while an already-running Chrome is
    # ready almost immediately.
    local _
    for _ in $(seq 40); do
        if swaymsg -t get_tree |
            jq -e --arg id "$browser_app_id" \
                'recurse(.nodes[]?, .floating_nodes[]?) | select(.app_id == $id)' >/dev/null; then
            swaymsg "[app_id=\"$browser_app_id\"] focus" >/dev/null
            return 0
        fi
        sleep 0.05
    done
}

result=$(list_path_bins | fuzzel --dmenu)
status=$?

[[ -z $result ]] && exit 0

case $status in
    # Alt+Enter: search regardless of what the text looks like.
    10)
        search_web "$result"
        ;;
    # Enter: run it if it really is an executable. type -P looks only at PATH,
    # so builtins and keywords fall through to the search instead of failing
    # silently in exec.
    0)
        if type -P "${result%% *}" >/dev/null 2>&1; then
            exec $result
        fi
        search_web "$result"
        ;;
    # Escape, or fuzzel failed to start.
    *)
        exit 0
        ;;
esac