#!/usr/bin/env fish

# Ensure stdin is a tty
test -t 0; or exit 0

# Avoid loading this file more than once
if test "$__MCFLY_LOADED" = "loaded"
  exit 0
end
set -g __MCFLY_LOADED "loaded"

# Note: we only use the history file for the session when this file was sourced.
# Would have to reset this before calling mcfly if you want commands from another session later.
if not set -q HISTFILE
  set -gx HISTFILE (set -q XDG_DATA_HOME; and echo $XDG_DATA_HOME; or echo $HOME/.local/share)/fish/(set -q fish_history; and echo $fish_history; or echo fish)_history
end
if not test -r "$HISTFILE"
  echo "McFly: $HISTFILE does not exist or is not readable. Please fix this or set HISTFILE to something else before using McFly." >&2
  exit 1
end

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

# Find the binary
set -q MCFLY_PATH; or set -l MCFLY_PATH (which mcfly)
if test -z "$MCFLY_PATH"; or test "$MCFLY_PATH" = "mcfly not found"
  echo "Cannot find the mcfly binary, please make sure that mcfly is in your path before sourcing mcfly.fish"
  exit 1
end
# We don't need a MCFLY_HISTORY file because we can get the last command in fish_postexec.
set -g __MCFLY_CMD $MCFLY_PATH --mcfly_history /dev/null --history_format fish

function __mcfly_save_old_pwd -d 'Save PWD before running command' -e fish_preexec
  set -g __MCFLY_OLD_PWD "$PWD"
end

function __mcfly_add_command -d 'Add run commands to McFly database' -e fish_postexec
  # First, retain return code of last command before we lose it
  set -l last_status $status
  # Handle first call of this function after sourcing mcfly.fish, when the old PWD won't be set
  set -q __MCFLY_OLD_PWD; or set -g __MCFLY_OLD_PWD "$PWD"

  test -n "$MCFLY_DEBUG"; and echo mcfly.fish: Run eval $__MCFLY_CMD add --exit '$last_status' --old-dir '$__MCFLY_OLD_PWD' '$argv[1]'
  eval $__MCFLY_CMD add --exit '$last_status' --old-dir '$__MCFLY_OLD_PWD' '$argv[1]'
end

# If this is an interactive shell, set up key binding functions.
if status is-interactive
  function __mcfly-history-widget -d "Search command history with McFly"
    set -l mcfly_output (mktemp -t mcfly.output.XXXXXXXX)
    eval $__MCFLY_CMD search -o '$mcfly_output' (commandline)

    # Interpret commandline/run requests from McFly
    set -l mode; set -l commandline
    while read key val
      test "$key" = "mode"; and set mode "$val"
      test "$key" = "commandline"; and set commandline "$val"
      test "$key" = "delete"; and history delete --exact --case-sensitive "$val"
    end < "$mcfly_output"
    rm -f $mcfly_output

    if test -n "$commandline"
      commandline "$commandline"
    end
    if test "$mode" = "run"
      commandline -f execute
    end
    commandline -f repaint
  end

  function mcfly_key_bindings -d "Default key bindings for McFly"
     bind \cr __mcfly-history-widget
     if bind -M insert >/dev/null 2>&1
       bind -M insert \cr __mcfly-history-widget
     end
  end
end
