mcfly.bash

#!/bin/bash

# Ensure stdin is a tty
# Avoid loading this file more than once
if [[ -t 0 ]] && [[ "$__MCFLY_LOADED" != "loaded" ]]; then
  __MCFLY_LOADED="loaded"

  # Setup MCFLY_HISTFILE and make sure it exists.
  export MCFLY_HISTFILE="${HISTFILE:-$HOME/.bash_history}"
  export MCFLY_BASH_SEARCH_KEYBINDING=${MCFLY_BASH_SEARCH_KEYBINDING:-"\M-1"}
  export MCFLY_BASH_ACCEPT_LINE_KEYBINDING=${MCFLY_BASH_ACCEPT_LINE_KEYBINDING:-"\M-2"}
  if [[ ! -r "${MCFLY_HISTFILE}" ]]; then
    echo "McFly: ${MCFLY_HISTFILE} does not exist or is not readable. Please fix this or set HISTFILE to something else before using McFly."
    return 1
  fi

  # MCFLY_SESSION_ID is used by McFly internally to keep track of the commands from a particular terminal session.
  MCFLY_SESSION_ID="$(command dd if=/dev/urandom bs=256 count=1 2> /dev/null | LC_ALL=C command tr -dc 'a-zA-Z0-9' | command head -c 24)"
  export MCFLY_SESSION_ID

  # Find the binary
  MCFLY_PATH=${MCFLY_PATH:-$(command which mcfly)}
  if [ -z "$MCFLY_PATH" ]; then
    echo "Cannot find the mcfly binary, please make sure that mcfly is in your path before sourcing mcfly.bash."
    return 1
  fi

  # Ignore commands with a leading space
  export HISTCONTROL="${HISTCONTROL:-ignorespace}"

  # Append new history items to .bash_history
  shopt -s histappend

  # Setup a function to be used by $PROMPT_COMMAND.
  function mcfly_prompt_command {
    local exit_code=$? # Record exit status of previous command.

    # Populate McFly's temporary, per-session history file from recent commands in the shell's primary HISTFILE.
    if [[ ! -f "${MCFLY_HISTORY}" ]]; then
      MCFLY_HISTORY=$(mktemp ${TMPDIR:-/tmp}/mcfly.XXXXXXXX)
      export MCFLY_HISTORY
      command tail -n100 "${MCFLY_HISTFILE}" >| "${MCFLY_HISTORY}"
    fi

    history -a "${MCFLY_HISTORY}" # Append history to $MCFLY_HISTORY.
    # Run mcfly with the saved code. It will:
    # * append commands to $HISTFILE, (~/.bash_history by default)
    #   for backwards compatibility and to load in new terminal sessions;
    # * find the text of the last command in $MCFLY_HISTORY and save it to the database.
    $MCFLY_PATH add --exit ${exit_code} --append-to-histfile "${MCFLY_HISTFILE}"
    # Clear the in-memory history and reload it from $MCFLY_HISTORY
    # (to remove instances of '#mcfly: ' from the local session history).
    history -cr "${MCFLY_HISTORY}"
    return ${exit_code} # Restore the original exit code by returning it.
  }

  # Runs mcfly search with output to file, reads the output, and sets READLINE_LINE to the command.
  # If the command is to be run, binds the MCFLY_KEYSTROKE2 to accept-line, otherwise binds it to nothing.
  function mcfly_search {
    # Get a temp file name but don't create the file - mcfly will create the file for us.
    MCFLY_OUTPUT=$(mktemp --dry-run ${TMPDIR:-/tmp}/mcfly.output.XXXXXXXX)
    echo \#mcfly: ${READLINE_LINE[@]} >> $MCFLY_HISTORY
    mcfly search -o $MCFLY_OUTPUT
    # If the file doesn't exist, nothing was selected from mcfly, exit without binding accept-line
    if [[ ! -f $MCFLY_OUTPUT ]];
    then
      bind "\"$MCFLY_BASH_ACCEPT_LINE_KEYBINDING\":\"\""
      return
    fi;
    # Get the command and set the bash text to it, and move the cursor to the end of the line.
    MCFLY_COMMAND=$(awk 'NR==2{$1=a; print substr($0, 2)}' $MCFLY_OUTPUT)
    READLINE_LINE=$MCFLY_COMMAND
    READLINE_POINT=${#READLINE_LINE}

    # Get the mode and bind the accept-line key if the mode is run.
    MCFLY_MODE=$(awk 'NR==1{$1=a; print substr($0, 2)}' $MCFLY_OUTPUT)
    if [[ $MCFLY_MODE == "run" ]];
    then
      bind "\"$MCFLY_BASH_ACCEPT_LINE_KEYBINDING\":accept-line"
    else
      bind "\"$MCFLY_BASH_ACCEPT_LINE_KEYBINDING\":\"\""
    fi;

    rm -f $MCFLY_OUTPUT
    return $LAST_EXIT_CODE
  }

  # Set $PROMPT_COMMAND run mcfly_prompt_command, preserving any existing $PROMPT_COMMAND.
  if [ -z "$PROMPT_COMMAND" ]
  then
    PROMPT_COMMAND="mcfly_prompt_command"
  elif [[ ! "$PROMPT_COMMAND" =~ "mcfly_prompt_command" ]]
  then
    PROMPT_COMMAND="mcfly_prompt_command;${PROMPT_COMMAND#;}"
  fi

  # If this is an interactive shell, take ownership of ctrl-r.
  if [[ $- =~ .*i.* ]]; then
    if [[ ${BASH_VERSINFO[0]} -ge 4 ]]; then
      # shellcheck disable=SC2016
      if [[ $MCFLY_BASH_USE_TIOCSTI = 1 ]]; then
        bind -x '"\C-r": "echo \#mcfly: ${READLINE_LINE[@]} >> $MCFLY_HISTORY ; READLINE_LINE= ; mcfly search"'
      else
        # Bind ctrl+r to 2 keystrokes, the first one is used to search in McFly, the second one is used to run the command (if mcfly_search binds it to accept-line).
        bind -x "\"$MCFLY_BASH_SEARCH_KEYBINDING\":\"mcfly_search\""
        bind "\"\C-r\":\"$MCFLY_BASH_SEARCH_KEYBINDING$MCFLY_BASH_ACCEPT_LINE_KEYBINDING\""
      fi
    else
      # The logic here is:
      #   1. Jump to the beginning of the edit buffer, add 'mcfly: ', and comment out the current line. We comment out the line
      #      to ensure that all possible special characters, including backticks, are ignored. This commented out line will
      #      end up as the most recent entry in the $MCFLY_HISTORY file.
      #   2. Type "mcfly search" and then run the command. McFly will pull the last line from the $MCFLY_HISTORY file,
      #      which should be the commented-out search from step #1. It will then remove that line from the history file and
      #      render the search UI pre-filled with it.
      if set -o | grep "vi " | grep -q on; then
        bind "'\C-r': '\e0i#mcfly: \e\C-m mcfly search\C-m'"
      else
        bind "'\C-r': '\C-amcfly: \e# mcfly search\C-m'"
      fi
    fi
  fi

fi