#! /usr/bin/env bash
set -e
shopt -s extglob
[ -n "$DOTIFY_DEBUG" ] && set -x

# dotify 0.0.1
# https://github.com/jimeh/dotify
#
# Copyright (c) 2013 Jim Myhrberg.
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.


#
# Helper functions
#

# Checks for specified argument.
#
# Example:
#
#   $ has-argument help h "-t none"
#   > returns 1
#   $ has-argument help h "-t none --help"
#   > returns 0
#   $ has-argument help h "-t none -h"
#   > returns 0
#
# Returns 0 if argument was found, returns 1 otherwise.
has-argument() {
  local long short

  long="--$1"
  short="-$2"
  shift 2

  if [[ " $@ " == *" $long "* ]] || [[ " $@ " == *" $long="* ]]; then
    return 0
  elif [[ " $@ " == *" $short "* ]] || [[ " $@ " == *" $short="* ]]; then
    return 0
  fi
  return 1
}

# Parses and echos value of specified argument.
#
# Example:
#
#   $ parse-argument file f -t none --file /tmp/foobar.txt
#   /tmp/foobar.txt
#   $ parse-argument file f -t none --file="/tmp/foo bar.txt"
#   /tmp/foo bar.txt
#   $ parse-argument file f -t none -f /tmp/foobar.txt
#   /tmp/foobar.txt
#   $ parse-argument file f -t none -f=/tmp/foo\ bar.txt
#   /tmp/foo bar.txt
#
# Returns 0 and echos value if argument was found, returns 1 otherwise.
parse-argument() {
  local long short arg next_arg

  long="--$1"
  short="-$2"
  shift 2

  for arg in "$@"; do
    if [ -n "$next_arg" ]; then
      echo "$arg"
      return 0
    elif [[ " $arg " == *" $long "* ]] || [[ " $arg " == *" $short "* ]]; then
      next_arg="yes"
    elif [[ " $arg " == *" $long="* ]]; then
      arg="${arg/#$long=/}"
      echo "$arg"
      return 0
    elif [[ " $arg " == *" $short="* ]]; then
      arg="${arg/#$short=/}"
      echo "$arg"
      return 0
    fi
  done
  return 1
}

# Trim leading and trailing whitespace.
#
# Example:
#
#   $ trim "  foo bar   "
#   foo bar
#
trim() {
  local string="$@"
  string="${string#"${string%%[![:space:]]*}"}"
  string="${string%"${string##*[![:space:]]}"}"
  echo -n "$string"
}


#
# Internal functions
#

compile-dotfile() {
  local dotfile="$1"
  if [ -z "$dotfile" ]; then dotfile="$DOTFILE"; fi

  if [ ! -f "$dotfile" ]; then
    echo "ERROR: \"$dotfile\" does not exist." >&2
    return 1
  fi

  local output=""
  local line=""
  while IFS= read line; do
    # Ignore comments and blank lines.
    if [[ "$line" =~ ^(\ *\#.*|\ *)$ ]]; then
      continue

    # Parse "<action>: <source> -> <target>" lines.
    elif [[ "$line" =~ ^(\ +)?([a-zA-Z0-9_-]+):\ (.+)\ +-[\>]\ +(.+)$ ]]; then
      output="${output}${BASH_REMATCH[1]}dotify-action ${BASH_REMATCH[2]} "
      output="${output}$(trim "${BASH_REMATCH[3]}") "
      output="${output}$(trim "${BASH_REMATCH[4]}")\n"

    # Parse "<source> -> <target>" lines.
    elif [[ "$line" =~ ^(\ +)?(.+)\ -[\>]\ (.+)$ ]]; then
      output="${output}${BASH_REMATCH[1]}dotify-action default "
      output="${output}$(trim "${BASH_REMATCH[2]}") "
      output="${output}$(trim "${BASH_REMATCH[3]}")\n"

    # Append line without modifications.
    else
      output="${output}${line}\n"
    fi
  done < "$dotfile"

  echo -e "$output"
}

create-symlink() {
  local source="$1"
  local target="$2"

  if [ ! -e "$target" ] && [ ! -h "$target" ]; then
    ln -s "$source" "$target"
    return 0
  elif [ -h "$target" ]; then
    if [ "$(readlink "$target")" != "$source" ]; then
      echo "ERROR: \"$target\" exists, is a symlink to:" \
        "$(readlink "$target")" >&2
      return 1
    fi
  else
    echo "ERROR: \"$target\" exists" >&2
    return 1
  fi
}

execute-dotfile() {
  local dotfile_source="$(dotify-compile)"

  locate-target
  if [ "$?" != "0" ]; then return 1; fi

  ROOT_DIR="$(dirname "$DOTFILE")"

  eval "$dotfile_source"
  return $?
}

locate-dotfile() {
  if [ -n "$DOTFILE" ]; then
    if [ ! -f "$DOTFILE" ]; then
      echo "ERROR: \"$DOTFILE\" does not exist." >&2
      return 1
    fi
  elif [ -f "$(pwd)/Dotfile" ]; then
    DOTFILE="$(pwd)/Dotfile"
  else
    echo "ERROR: \"$(pwd)\" does not have a Dotfile." >&2
    return 1
  fi
}

locate-target() {
  if [ -n "$TARGET" ]; then
    if [ ! -d "$TARGET" ]; then
      echo "ERROR: Target \"$TARGET\" is not a directory." >&2
      return 1
    fi
  elif [ -n "$HOME" ] && [ -d "$HOME" ]; then
    TARGET="$HOME"
  elif [ -d ~ ]; then
    TARGET=~
  else
    echo "ERROR: Your \$HOME folder could not be found." >&2
    return 1
  fi
}


#
# Command functions
#

dotify-action() {
  local action="$1"
  local source="$2"
  local target="$3"

  if [ "$action" == "default" ]; then
    action="$DOTIFY_OPT_DEFAULT_ACTION"
  fi

  ! valid_action="$(command -v "dotify-action-${action}")"
  if [ -z "$valid_action" ]; then
    echo "ERROR: \"$action\" is not a valid action." >&2
    return 1
  fi

  dotify-action-${action} "$source" "$target"
}

dotify-clean() {
  DOTIFY_RUN_MODE="clean"
  execute-dotfile
  return $?
}

dotify-compile() {
  locate-dotfile
  if [ "$?" != "0" ]; then return 1; fi

  compile-dotfile "$DOTFILE"
  return $?
}

dotify-help() {
  echo "$(dotify-print-version)"
  echo "usage: dotify <command> [<args>]"
}

dotify-info() {
  locate-dotfile
  if [ "$?" != "0" ]; then return 1; fi

  locate-target
  if [ "$?" != "0" ]; then return 1; fi

  echo "$(dotify-print-version)"
  echo "  Dotfile: $DOTFILE"
  echo "     Root: $(dirname "$DOTFILE")"
  echo "   Target: $TARGET"
}

dotify-install() {
  DOTIFY_RUN_MODE="install"
  execute-dotfile
  return $?
}

dotify-uninstall() {
  DOTIFY_RUN_MODE="uninstall"
  execute-dotfile
  return $?
}

dotify-version() {
  echo "0.0.1"
}

dotify-print-version() {
  echo "dotify $(dotify-version)"
}


#
# Built-in Plugins
#

dotify-action-link() {
  if [ "$DOTIFY_RUN_MODE" == "install" ]; then
    dotify-action-link-install $@
  elif [ "$DOTIFY_RUN_MODE" == "uninstall" ]; then
    dotify-action-link-uninstall $@
  fi
}

dotify-action-link-install() {
  echo "link install: $@"
}

dotify-action-link-uninstall() {
  echo "link uninstall: $@"
}

dotify-action-git() {
  if [ "$DOTIFY_RUN_MODE" == "install" ]; then
    dotify-action-git-install $@
  elif [ "$DOTIFY_RUN_MODE" == "uninstall" ]; then
    dotify-action-git-uninstall $@
  fi
}

dotify-action-git-install() {
  echo "git install: $@"
}

dotify-action-git-uninstall() {
  echo "git uninstall: $@"
}


#
# Dotfile commands
#

root_link () {
  DOTIFY_OPT_ROOT_LINK="$@"
}

default_action() {
  DOTIFY_OPT_DEFAULT_ACTION="$@"
}

include() {
  echo "include: $@"
}


#
# Default Options
#

DOTIFY_OPT_ROOT_LINK=".dotfiles"
DOTIFY_OPT_DEFAULT_ACTION="link"

#
# Argument Parsing
#

DOTFILE="" # --dotfile / -f
TARGET=""  # --target  / -t
DRY_RUN="" # --dry-run / -d
HELP=""    # --help    / -h
VERSION="" # --version / -v

if has-argument dotfile f "$@"; then
  DOTFILE="$(parse-argument dotfile f "$@")"
fi

if has-argument target t "$@"; then
  TARGET="$(parse-argument target t "$@")"
fi

if has-argument dry-run d "$@"; then
  DRY_RUN="1"
fi

if has-argument help h "$@"; then
  HELP="1"
fi

if has-argument version v "$@"; then
  VERSION="1"
fi


#
# Command Parsing
#

# Command is first argument that does not start with a dash or plus.
for arg in "$@"; do
  if [ -n "$skip_next" ]; then
    skip_next=
  elif [[ "$arg" =~ ^(--dotfile|-f|--taraget|-t)$ ]]; then
    skip_next=1
  elif [[ "$arg" != "-"* ]] && [[ "$arg" != "+"* ]]; then
    command="$arg"
    break
  fi
done

# Show help and exit if help arguments or command are given.
if [ -n "$HELP" ] || [ "$command" == "help" ]; then
  dotify-help
  exit
fi

# Show version info and exit if version arguments or command are given.
if [ -n "$VERSION" ] || [ "$command" == "version" ]; then
  dotify-help | head -1
  exit
fi

# Deal with the commands.
case "$command" in
  "info" )
    dotify-info
    ;;
  "compile" )
    dotify-compile
    ;;
  "" | "install" )
    dotify-install
    ;;
  "uninstall" | "remove" )
    dotify-uninstall
    ;;
  "clean" )
    dotify-clean
    ;;
esac

exit $?