#! /usr/bin/env bash
set -e
[ -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
#

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
}

create-rootlink() {
  local root="$1"
  local rootlink="$2"
}

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

parse-dotfile() {
  local dotfile="$1"
  local target="$2"
  local rootlink="$(parse-dotfile-rootlink "$dotfile")"

  local rootdir="$(dirname "$dotfile")"
  local cwd="$(pwd)"
  cd "$rootdir"

  create-rootlink "$rootdir" "$target/$rootlink"
  if [ -n "$?" ]; then return 1; fi

  while read line; do
    parse-dotfile-line "$dotfile" "$target" "$rootdir" "$rootlink" "$line"
    if [ -n "$?" ]; then return 1; fi
  done < "$dotfile"

  cd "$cwd"
}

parse-dotfile-rootlink() {
  local dotfile="$1"
  local rootlink

  while read line; do
    if [[ "$line" == "root_link "* ]]; then
      rootlink=${line/#root_link /}
      break
    fi
  done < "$dotfile"

  if [ -z "$rootlink" ]; then rootlink=".dotfiles"; fi

  echo "$root_link"
}

parse-dotfile-line() {
  local dotfile="$1"
  local target="$2"
  local rootdir="$3"
  local rootlink="$4"
  local line="$5"

  # Ignore comment lines starting with "#".
  if [[ "$line" == "#"* ]]; then return 0; fi

  # Ignore root link command.
  if [[ "$line" == "root_link "* ]]; then return 0; fi

  # Handle include command.
  if [[ "$line" == "include "* ]]; then
    include-dotfile "${line/#include /}" "$target" "$rootdir" "$rootlink"
    return "$?"
  fi

  echo "$line"
}

include-dotfile() {
  local dotfile="$1"
  local target="$2"
  local rootdir="$3"
  local rootlink="$4"

  local cwd="$(pwd)"
  cd "$rootdir"

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

  while read line; do
    parse-dotfile-line "$dotfile" "$target" "$rootdir" "$rootlink" "$line"
    if [ -n "$?" ]; then return 1; fi
  done < "$dotfile"

  cd "$cwd"
}


#
# Command functions
#

dotify-version() {
  echo "0.0.1"
}

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

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

dotify-info() {
  local dotfile="$(locate-dotfile "$@")"
  if [ -z "$dotfile" ]; then return 1; fi

  local target="$(locate-target "$@")"
  if [ -z "$target" ]; then return 1; fi

  echo "dotify $(dotify-version)"
  echo "  Dotfile: $dotfile"
  echo "     Root: $(dirname "$dotfile")"
  echo "   Target: $target"
}

dotify-install() {
  local dotfile="$(locate-dotfile)"
  if [ -z "$dotfile" ]; then return 1; fi

  local target="$(locate-target)"
  if [ -z "$target" ]; then return 1; fi

  parse-dotfile "$dotfile" "$target"
  return $?
}


#
# Argument Parsing
#

DOTFILE="" # --dotfile / -f
TARGET=""  # --target  / -t
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 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 "$@"; do
  if [[ "$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
    ;;
  "" | "install" )
    dotify-install
    ;;
esac

exit $?