#!/bin/bash
#
# [X] open section
# [X] one shot mode
# [X] usage info
# [X] dependencies check
# [X] help
# [X] yank/y/copy/c
# [X] Y/C
# [X] eof problem
# [X] less
# [X] stealth mode
#
# here are several examples for the stealth mode:
#
# zip lists
# list permutation
# random list element
# reverse a list
# read json from file
# append string to a file
# run process in background
# count words in text counter
# group elements list

__CHTSH_VERSION=2
__CHTSH_DATETIME="2018-06-02 22:26:46 +0200"

STEALTH_MAX_SELECTION_LENGTH=5

do_query()
{
  local query="$*"
  local b_opts=()

  if [ -e "$HOME/.cht.sh/id" ]; then
    b_opts=(-b "$HOME/.cht.sh/id")
  fi

  curl "${b_opts[@]}" -s https://cht.sh/"$query" > "$TMP1"

  if [ -z "$lines" ] || [ "$(wc -l "$TMP1" | awk '{print $1}')" -lt "$lines" ]; then
    cat "$TMP1"
  else
    less -R "$TMP1"
  fi
}

prepare_query()
{
  local section="$1"; shift
  local input="$1"; shift
  local arguments="$1"; shift

  local query
  if [ -z "$section" ] || [[ "$input" = /* ]]; then
    query=$(echo "$input" | sed 's@ @/@; s@ @+@g')
  else
    query=$(echo "$section/$input" | sed 's@ @+@g')
  fi

  [ -n "$arguments" ] && arguments="?$arguments"
  echo "$query$arguments"
}

get_list_of_sections()
{
  curl -s https://cht.sh/:list | grep -v '/.*/' | grep '/$'
}

if [ "$1" == --read ]; then
  read -r a || a=exit
  echo $a
  exit 0
elif [ "$1" == --help ] || [ -z "$1" ]; then
  cat <<EOF
Usage:

    ${0##*/} --help           show this help
    ${0##*/} --shell [LANG]   shell mode (open LANG if specified)
    ${0##*/} QUERY            process QUERY and exit
EOF
  exit 0
elif [ "$1" == --shell ]; then
  shell_mode=yes
  shift
fi

if [ "$shell_mode" != yes ]; then
  opts=""
  input=""
  for o; do
    if [[ "$o" == -* ]]; then
      opts="${opts}${o#-}"
    else
      input="$input $o"
    fi
  done
  query=$(echo "$input" | sed 's@ *$@@; s@^ *@@; s@ @/@; s@ @+@g')
  curl -s https://cht.sh/"$query"
  exit 0
fi

which xsel >& /dev/null || { echo 'DEPENDENCY: please install "xsel" for "copy"' >&2; }
which rlwrap >& /dev/null || { echo 'DEPENDENCY: install "rlwrap" to use cht.sh in the shell mode' >&2; exit 1; }
which curl >& /dev/null || { echo 'DEPENDENCY: install "curl" to use cht.sh' >&2; exit 1; }

mkdir -p $HOME/.cht.sh/
lines=$(tput lines)

prompt="cht.sh"
section="$1"

TMP1=$(mktemp /tmp/cht.sh.XXXXXXXXXXXXX)
trap 'rm -rf $TMP1 $TMP2' EXIT

[ -e "$HOME/.cht.sh/.hushlogin" ] || { echo "type 'help' for the cht.sh shell help"; }

while true; do
  if [ "$section" != "" ]; then
    full_prompt="$prompt/$section> "
  else
    full_prompt="$prompt> "
  fi

  input=$(rlwrap -H $HOME/.cht.sh/history -pgreen -C cht.sh -S "$full_prompt" bash "$0" --read)

  case "$input" in
    '?'|h|help)
      cat <<EOF
help    - show this help
hush    - do not show the 'help' string at start anymore
cd LANG - change the language context
copy    - copy the last answer in the clipboard (aliases: yank, y, c)
ccopy   - copy the last answer w/o comments (cut comments; aliases: cc, Y, C)
exit    - exit the cheat shell (aliases: quit, ^D)
id [ID] - set/show an unique session id ("reset" to reset, "remove" to remove)
stealth - stealth mode (automatic queries for selected text)
update  - self update (only if the scriptfile is writeable)
version - show current cht.sh version
/:help  - service help
QUERY   - space ceparated query staring (examples are below)
              cht.sh> python zip list
              cht.sh/python> zip list
              cht.sh/go> /python zip list
EOF
      continue
      ;;
    hush)
      mkdir -p $HOME/.cht.sh/ && touch $HOME/.cht.sh/.hushlogin && echo "Initial 'use help' message was disabled"
      continue
      ;;
    cd)
      section=""
      continue
      ;;
    "cd "*)
      new_section=$(echo "$input" | sed 's/cd //; s/ .*//; s@/\+$@@; s@^/\+@@')
      if [ "$new_section" = "" ] || [ "$new_section" = ".." ] || [ "$new_section" = / ]; then
        section=""
      else
        valid_sections=($(get_list_of_sections))
        valid=no; for q in "${valid_sections[@]}"; do [[ "$q" == $new_section/ ]] && { valid=yes; break; }; done
        if [ "$valid" = no ]; then
          echo "Invalid section: $new_section"
          echo "Valid sections:"
          echo "${valid_sections[@]}" | xargs printf "%-10s\n" | tr ' ' .  | xargs -n 10 | sed 's/\./ /g; s/^/  /'
          continue
        else
          section="$new_section"
        fi
      fi
      continue
      ;;
    exit|quit)
      break
      ;;
    copy|yank|c|y)
      if [ -z "$input" ]; then
        echo copy: Make at least one query first.
        continue
      else
        curl -s https://cht.sh/"$query"?T > "$TMP1"
        xsel -i < "$TMP1"
        echo "copy: $(wc -l "$TMP1" | awk '{print $1}') lines copied to the selection"
        continue
      fi
      ;;
    ccopy|cc|C|Y)
      if [ -z "$input" ]; then
        echo copy: Make at least one query first.
        continue
      else
        curl -s https://cht.sh/"$query"?TQ > "$TMP1"
        xsel -i < "$TMP1"
        echo "copy: $(wc -l "$TMP1" | awk '{print $1}') lines copied to the selection"
        continue
      fi
      ;;
    id|"id "*)
      id_file="$HOME/.cht.sh/id"

      if [ "$input" = id ]; then
        new_id=""
      else
        new_id=$(echo "$input" | sed 's/id \+//; s/ *$//; s/ /+/g')
      fi
      if [ "$new_id" = remove ]; then
        if [ -e "$id_file" ]; then
          rm -f "$id_file" && echo "id is removed"
        else
          echo "id was not set, so you can't remove it"
        fi
        continue
      fi
      if [ -n "$new_id" ] && [ "$new_id" != reset ] && [ "$(echo $new_id | wc -c)" -lt 16 ]; then
        echo "ERROR: $new_id: Too short id. Minimal id length is 16. Use 'id reset' for a random id"
        continue
      fi
      if [ -z "$new_id" ]; then
        # if new_id is not specified check if we have some id already
        # if yes, just show it
        # if not, generate a new id
        if [ -e "$id_file" ]; then
          echo $(cat "$id_file" | awk '{if ($6 == "id") print $NF}' | head -1)
          continue
        else
          new_id=reset
        fi
      fi
      if [ "$new_id" = reset ]; then
        new_id="$(cat /dev/urandom 2> /dev/null | env LC_CTYPE=C tr -cd 'a-f0-9' 2> /dev/null | head -c 32)"
      else
        echo WARNING: if someone gueses your id, he can read your cht.sh search history
      fi
      if [ -e "$id_file" ] && grep -q '\tid\t[^\t]\+$' "$id_file" 2> /dev/null; then
        sed -i 's/\tid\t[^\t]\+$/ id '"$new_id"'/' "$id_file"
      else
        if ! [ -e "$id_file" ]; then
          printf '#\n\n' > "$id_file"
        fi
        printf ".cht.sh\tTRUE\t/\tTRUE\t0\tid\t$new_id\n" >> "$id_file"
      fi
      echo "$new_id"
      continue
      ;;
    stealth|"stealth "*)
        if [ "$input" != stealth ]; then
          arguments=$(echo "$input" | sed 's/stealth //; s/ /\&/')
        fi
        trap break SIGINT
        past=$(xsel -o)
        printf "\033[0;31mstealth:\033[0m you are in the stealth mode; select any text in any window for a query\n"
        printf "\033[0;31mstealth:\033[0m selections longer than $STEALTH_MAX_SELECTION_LENGTH words are ignored\n"
        if [ -n "$arguments" ]; then
          printf "\033[0;31mstealth:\033[0m query arguments: ?$arguments\n"
        fi
        printf "\033[0;31mstealth:\033[0m use ^C to leave this mode\n"
        while true; do
          current=$(xsel -o)
          if [ "$past" != "$current" ]; then
            past=$current
            if [ $(echo $current | wc -w) -gt "$STEALTH_MAX_SELECTION_LENGTH" ]; then
              echo "\033[0;31mstealth:\033[0m selection length is longer than $STEALTH_MAX_SELECTION_LENGTH words; ignoring"
              continue
            else
              current_text="$(echo $current | tr -c '[a-zA-Z0-9]' ' ')"
              printf "\n\033[0;31mstealth: \033[7m $current_text\033[0m\n"
              query=$(prepare_query "$section" "$current_text" "$arguments")
              do_query "$query"
            fi
          fi
          sleep 1;
        done
        trap - SIGINT
        continue
      ;;
    update)
      [ -w "$0" ] || { echo "The script is readonly; please update manually: curl -s https://cht.sh/:bash | sudo tee $0"; continue; }
      TMP2=$(mktemp /tmp/cht.sh.XXXXXXXXXXXXX)
      curl -s https://cht.sh/:bash > "$TMP2"
      if ! cmp "$0" "$TMP2" > /dev/null 2>&1; then
        args=(--shell)
        [ -n "$section" ] && args=("${args[@]}" "$section")
        cp "$TMP2" "$0" && echo "Updated. Restarting..." && exec "$0" "${args[@]}"
      else
        echo "cht.sh is up to date. No update needed"
      fi
      rm -f "$TMP2" > /dev/null 2>&1
      continue
      ;;
    version)
      echo "cht.sh version $__CHTSH_VERSION of $__CHTSH_DATETIME; installed at: $(stat -c %y "$0" | sed 's@\..* @ @')"
      TMP2=$(mktemp /tmp/cht.sh.XXXXXXXXXXXXX)
      if curl -s https://cht.sh/:bash > "$TMP2"; then
        if ! cmp "$0" "$TMP2" > /dev/null 2>&1; then
          echo "Update needed (type 'update' for that)".
        else
          echo "Up to date. No update needed"
        fi
      fi
      rm -f "$TMP2" > /dev/null 2>&1
      continue
      ;;
    "")
      continue
      ;;
  esac

  query=$(prepare_query "$section" "$input")
  do_query "$query"
done