#!/bin/bash
XL_PRODUCT="Vim Note System"
XL_VER="1.0a2"

# Environment Constants
readonly VNS_STORE="$HOME/.local/vns"
readonly VNS_KEYFILE="$VNS_STORE/.pubkey"
readonly IFS=$'\n\t'
set -euo pipefail

readonly VNS_RED_COLOR='\033[1;31m'
readonly VNS_YELLOW_COLOR='\033[1;33m'
readonly VNS_RESET_COLOR='\033[0m'

# Erroneous Exit Constants
  
  # Invocation Errors   
    readonly VNS_ERR_NO_STORE=5 # The vns store needs to be initialized
    readonly VNS_ERR_NO_OPTS=10 # No mode argument was specified
    readonly VNS_ERR_NS_ARGS=11 # The specified mode requires an argument
    readonly VNS_ERR_NO_EDTR=15 # No editor specified in environment
  # Dependency Errors
    readonly VNS_ERR_DEPS=20   # Base error - add the following codes
    readonly VNS_ERR_NO_gpg2=1  # GPG is not installed 
    readonly VNS_ERR_NO_tree=2 # Tree is not installed
    readonly VNS_ERR_NO_git=3  # Git is not installed
    
# Global Variables
typeset -a VNS_ACTION=("")
typeset -a MISSING_DEPS
typeset -i VNS_EXIT=0
declare    VNS_PUBKEY= 
# Function Definitions
# vns_index          Print the $1th index of array ${2[@]} (friendly to -euo)
# vns_printError     Prints an error message
# vns_NoteHeader     Prints standard note header to stdout
# vns_checkDeps      Checks the system for required dependencies
# vns_checkStore     Checks if $VNS_STORE exists
# vns_sanityCheck    Wrapper for vns_checkDeps and vns_checkStore
# ----
# vns_initStore      Initializes the VNS Store                             ( -i)
# vns_printHelp      Prints help page                                      ( -h)
# vns_list           Lists all notes in `tree` format                      (  *)
# vns_create         Creates note; calls vns_edit()                        ( -c)
# vns_edit           Decrypts note to /tmp, calls editor, re-encrypts note ( -e)
# vns_print          Prints note to stdout                                 ( -p)
# vns_rm             Deletes note from store                               ( -d)
# vns_gitPassthrough Passes through all instructions to git                (git)

function vns_index(){
  echo "$@" | awk -v i="$(($1+1))" '{print $i}'
}
function vns_printError(){
  printf "$VNS_RED_COLOR!$VNS_RESET_COLOR - %s\n" "$@"
}
function vns_NoteHeader(){
  printf "%s\n%s\n" "Title:" "Date:"
}
function vns_checkDeps(){
  local VNS_RETURN="true";
  for DEP in "${VNS_DEPS[@]}"; do
    if test  ! -e "$(which "$DEP" 2>/dev/null)"; then
      MISSING_DEPS+=("$DEP")
      VNS_RETURN="false";
    fi
  done
  "$VNS_RETURN";
}
function vns_checkStore(){
  if [ -d "$VNS_STORE" ]; then true; else false; fi
}
function vns_sanityCheck {
  if ! vns_checkDeps; then
    VNS_EXIT="$VNS_ERR_DEPS"
    for DEP in "${MISSING_DEPS[@]}"; do
      local VNS_DEP_EC="\$ERR_NO_$DEP"
      vns_printError "Dependency %s not in path." "$DEP";
      VNS_EXIT+=${!VNS_DEP_EC}
    done
  fi
  
  if [ -r "$VNS_STORE/.pubkey" ]; then
    VNS_PUBKEY="$(cat "$VNS_STORE/.pubkey")"
  elif ! vns_checkStore; then
    if [ "$(vns_index "1" "${VNS_ACTION[@]}")" != "vns_initStore" ]; then
      vns_printError "The vns store does not exist."
      printf "  - %s\n" "Please run \`vns -i [gpg-key]\` to initialize vns."
      VNS_EXIT="$VNS_ERR_NO_STORE"
    fi
  fi
}
#----
function vns_initStore {
  mkdir -p "$VNS_STORE"
  echo "$@" | awk '{print $1}' > "$VNS_KEYFILE"
}
function vns_printHelp(){
    printf "%s" "usage: vns [-cedlp] <notebook/section/name>"
    printf "\n%s" "       vns -i <gnupg recipient>"
    printf "\n%s" "       vns -h"
    printf "\n%s%s%s" "usage: vns " "git" " ..."

    printf "\n%s" "  -c | --create : Create note"
    printf "\n%s" "  -d | --delete : Delete note"
    printf "\n%s" "  -e | --edit   : Open note for editing"
    printf "\n%s" "  -h | --help   : Display this message"
    printf "\n%s" "  -i | --init   : Write default config and initalize VNS store"
    printf "\n%s" "  -l | --list   : List all notes in NOTEBOOK"
    printf "\n%s" "  -p | --print  : Print note to console"
    printf "\n\n"
}
function vns_list(){
  # Print the tree
    tree -C --noreport --prune "$VNS_STORE/$(vns_index "1" "$@")" | tail -n +2 | sed s/\.gpg//g
}

function vns_rm(){
  local readonly VNS_NOTE; VNS_NOTE="$VNS_STORE/$(vns_index "1" "$@").gpg"
  echo "Deleting $VNS_NOTE"
  rm -f "$VNS_NOTE"
}
function vns_create(){
  local readonly VNS_NOTE; VNS_NOTE="$VNS_STORE/$(vns_index "1" "$@").gpg"
  # Make sure the note doesn't already exist
    if [ -r "$VNS_NOTE" ]; then 
      vns_printError "Note already exists."
    else
      if [ ! -d "$(dirname "$VNS_NOTE")" ]; then
        mkdir -p "$(dirname "$VNS_NOTE")"
      fi
      vns_NoteHeader | gpg2 -e -r "$VNS_PUBKEY" -o "$VNS_NOTE"
      vns_edit "$@"
    fi
}

function vns_edit(){
  # Make the function more readable
  local readonly VNS_NOTE; VNS_NOTE="$VNS_STORE/$(vns_index "1" "$@").gpg"
  # Edit the note
    vim "$VNS_NOTE"
}
function vns_print(){
  gpg2 -d "$VNS_STORE/$(vns_index "1" "$@").gpg"
}
function vns_gitPassthrough(){
  cd "$VNS_STORE" || exit;
  git "$@";
}
# ----
function vns_argParse(){
  ARGS=($@)
  #echo "${#ARGS}"
  VNS_ACTION=()
  while getopts ":i:hc:e:p:d:" OPT; do
 
    # If an option requiring an argument was passed without an argument,
    # inform the user and set exit code to "$VNS_ERR_NS_ARGS"
    case "${ARGS[!OPTIND]}" in 
      -i|-c|-e|-p|-d)
        if [ "${#ARGS}" -lt 2 ]; then
          vns_printError "A required argument was not given."
          VNS_EXIT="$VNS_ERR_NS_ARGS"
          return
        fi
    esac
    case "$OPT" in
      i)
        VNS_ACTION=("vns_initStore" "$OPTARG");;
      h)
        VNS_ACTION=("vns_printHelp");;
      c)
        VNS_ACTION=("vns_create $OPTARG");;
      e)
        VNS_ACTION=("vns_edit $OPTARG");;
      p)
        VNS_ACTION=("vns_print $OPTARG");;
      d)
        VNS_ACTION=("vns_rm $OPTARG");;
    esac
  done
  
  if [ "${#VNS_ACTION[@]}" -eq 0 ]; then
    if [ "$(vns_index "1" "$@")" == "git" ]; then
      VNS_ACTION=($@)
    else
      if [ -d "$VNS_STORE/$*" ]; then
        VNS_ACTION=("vns_list" "$@")
      else
        VNS_ACTION=("vns_list" "")
      fi
    fi
  fi
}

# Entry Point
printf "%s, %s\n" "$XL_PRODUCT" "$XL_VER"
printf "\n"
cd "$VNS_STORE" || exit;

readonly VNS_EDITOR="vim"
readonly VNS_DEPS=("vim" "gpg2" "tree" "git")

  



vns_argParse "$@"
vns_sanityCheck
if [ "$VNS_EXIT" -eq 0 ]; then
  eval "${VNS_ACTION[@]}"
fi

printf "\n"

exit "$VNS_EXIT"