#!/usr/bin/env nix-shell
#! nix-shell -i oil -p coreutils ripgrep handlr gnused xxd

# A ripoff from Duckduckgo bangs.

# Examples:
# ```
# bangs hello there ~g ~aw
# ```
# will open a search result page on Google and Arch Wiki

proc usage() {
    cat <<HELP
bangs - a ripoff from Duckduckgo bangs, except
        you can open multiple pages in one go.

Usage:
    bangs [SEARCH_QUERY...] [BANGS...]

A bang is absolutely necessary to indicate what search pages
to open.

While there is a default config, you should create your own list
by setting a config file at '\${XDG_CONFIG_HOME}/bangs/config.json'.
The config is simply a JSON file with the bang as the key and an
object with 'url' and 'name'.

Examples:
- Google and Duckduckgo search
    bangs hello world ~g ~ddg

- Change the bangs prefix
    BANGS_PREFIX="--" bangs how to program in python --g --yt
HELP
}

# These are the default bangs available.
# Bangs are any keys that shouldn't have whitespace characters.
const config_dir = "${XDG_CONFIG_HOME:-"$HOME/.config"}/bangs"
const config_file = "${config_dir}/config.json"
const default_config = {
    'aw': {
        'name': 'Arch Wiki',
        'url': 'https://wiki.archlinux.org/index.php?title=Special%3ASearch&search={{{s}}}'
    },
    'gh': {
        'name': 'GitHub',
        'url': 'https://github.com/search?utf8=%E2%9C%93&q={{{s}}}'
    },
    'g': {
        'name': 'Google',
        'url': 'https://www.google.com/search?q={{{s}}}'
    },
    'so': {
        'name': 'Stack Overflow',
        'url': 'http://stackoverflow.com/search?q={{{s}}}'
    },
    'w': {
        'name': 'Wikipedia',
        'url': 'https://en.wikipedia.org/wiki/Special:Search?search={{{s}}}'
    }
}

const bangs_prefix = "${BANGS_PREFIX:-~}"
const bangs_placeholder = "${BANGS_PLACEHOLDER:-{{{s}}}}"
const bangs_format = / %start $bangs_prefix !space+ %end /
const valid_bangs = %()
const search_query = %()
if test -f $config_file {
  json read :bangs < $config_file
} else {
  var bangs = default_config
}

# Stolen from https://gist.github.com/cdown/1163649 and https://gist.github.com/cdown/1163649#gistcomment-1256298
proc urlencode(msg) {
  for (i in 0:len(msg)) {
    var char = msg[i - 1]

    case $char {
        [a-zA-Z0-9.~_-])
          printf '%s' $char
          ;;
        *)
          printf '%s' $char | xxd -plain -cols 1 | while read :hex { printf '%%%s' $hex }
          ;;
    }
  }
}

proc warnf(format, @msg) {
  >&2 printf "$format\\n" @msg
}

if (len(ARGV) == 0) {
  usage
  exit 0
}

for i in @ARGV {
  write -- $i | rg --quiet $bangs_format || {
    push :search_query $i
    continue
  }

  var bang = $(write -- $i | sed --regexp-extended --expression "s/^${bangs_prefix}//")
  if (bang in bangs) {
    push :valid_bangs $bang
    warnf "%s will be used to search." $bang
  } else {
    warnf "%s is not found in the database." $bang
  }
}

var query = $(printf "%s " @search_query)
warnf "Search query is '%s'" $query

for bang in @valid_bangs {
  var metadata = bangs[bang]
  var url = $(write -- ${metadata['url']} | sed --expression "s/${bangs_placeholder}/$(urlencode $query)/")

  handlr open $url
}