#!/bin/bash

#
# ===== dckr =====
#
# Copyright 2020 Jan Heuermann (https://www.jotaen.net)
#
# 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.
#

ini_path=~/.dckr
ini_contents=()
flag_help=0
flag_verbose=0
flag_list=0
flag_describe=0
flag_readonly=""
all_section_names=()
section_name=""
section_exists=0
additional_args=()
additional_cmd=()
config_image=()
config_args=()
config_cmd=()

parse_and_load() {
  PATTERN_ENTRY='^[[:space:]]*(image|args|cmd)[[:space:]]*=[[:space:]]*(.*)'
  PATTERN_SECTION='^[[:space:]]*\[[[:space:]]*([a-zA-Z0-9:._-]+)[[:space:]]*\]'
  section=""
  for line in "${ini_contents[@]}"; do
    if [[ "$line" =~ ^[[:space:]]*\;.* ]] || [[ "$line" =~ ^[[:space:]]*$ ]]; then
      continue
    fi
    if [[ "$line" =~ $PATTERN_SECTION ]]; then
      section=${BASH_REMATCH[1]}
      all_section_names+=( $section )
      if [[ "$section" == "$1" ]]; then
        eval section_exists=1
      fi
      continue
    fi
    if [[ "$section" != "$1" ]]; then
      continue
    fi
    if [[ "$line" =~ $PATTERN_ENTRY ]]; then
      key=${BASH_REMATCH[1]}
      value=${BASH_REMATCH[2]}
      eval config_$key=\( $value \)
    else
      echo "Error: malformed syntax '$line'"
      exit 1
    fi
  done
}

while (( ${#@} )); do # Process input
  if [[ "$section_name" == "" ]]; then # 1. Input meant for this script
    if [[ "$1" =~ ^-.+ ]]; then # 2. dckr flags
      case $1 in
        "-h" | "--help") flag_help=1;;
        "-v" | "--verbose") flag_verbose=1;;
        "-ls" | "--list") flag_list=1;;
        "-d" | "--describe") flag_describe=1;;
        "-ro" | "--readonly") flag_readonly=":ro";;
        *)
          echo "Error: Unrecognized flag $1"
          exit 1
      esac
    else # 3. Section name
      section_name=$1
    fi
  else
    if [[ "$1" != "--" ]]; then # 4.Flags for docker run
      additional_args+=($1)
    else # 5. Separator
      shift 1 # Skip `--` separator
      additional_cmd="${@}"
      break # done
    fi
  fi
  shift 1
done

if [[ ! -f $ini_path ]]; then
  echo "Error: no config file found '$ini_path'"
  exit 1
fi

# Read the file and convert to line array
IFS=$'\n' && file="$(<$ini_path)" ini_contents=( ${file} )

# Print help
if [[ "$flag_help" == 1 ]]; then
  echo "dckr is a command line utility that makes it quick and convenient"
  echo "to execute predefined 'docker run' configurations."
  echo
  echo "Usage: dckr [OPTIONS] NAME [ARGS] [-- CMD]"
  echo
  echo "    OPTIONS   (See below)"
  echo "    NAME      Refers to one specific configuration in ~/.dckr"
  echo "    ARGS      Additional arguments that you want to be"
  echo "              passed to 'docker run'"
  echo "    CMD       Additional command that you want to pass to the"
  echo "              entrypoint (delimited by a double-dash)"
  echo
  echo "Options:"
  echo "    --help      -h    Print help"
  echo "    --verbose   -v    Print docker command before executing"
  echo "    --list      -ls   Enumerate all available configurations"
  echo "    --describe  -d    Print parameters of a specific configuration"
  echo "    --readonly  -ro   Mount current directory as readonly"
  exit 0
fi

# Load config into env variables
parse_and_load $section_name

# Print list of all available configurations
if [[ "$flag_list" == 1 ]]; then
  for s in "${all_section_names[@]}"; do
    echo $s
  done
  exit 0
fi

if [[ "$section_name" == "" ]]; then
  echo "Error: no input argument given"
  exit 1
fi
if [[ "$section_exists" != "1" ]]; then
  echo "Error: no configuration found for alias '$section_name' in $ini_path"
  exit 1
fi
if [[ "$config_image" == "" ]]; then
  echo "Error: no image specified for alias '$section_name' in $ini_path"
  exit 1
fi

# Print info about image
if [[ "$flag_describe" == 1 ]]; then
  echo "Image: $config_image"
  echo "Arguments: ${config_args[@]}"
  echo "Command: ${config_cmd[@]}"
  exit 0
fi

run=( \
  --rm \
  --tty \
  --interactive \
  --workdir=/dckr \
  --volume=$(pwd):/dckr$flag_readonly \
  "${config_args[@]}" \
  "${additional_args[@]}" \
  $config_image \
  "${config_cmd[@]}" \
  "${additional_cmd[@]}" \
)

if [[ "$flag_verbose" == 1 ]]; then
  echo docker run ${run[@]}
  echo
fi

docker run ${run[@]}