#!/bin/bash
XL_PRODUCT="Simple Note System"
XL_VER="v2a"

# Environment Constants
readonly SNS_STORE="$HOME/.local/sns"
readonly SNS_KEYFILE="$SNS_STORE/.pubkey"
readonly SNS_DEPS=("gpg2" "tree" "git")
readonly IFS=$'\n\t'
set -euo pipefail

readonly SNS_RED_COLOR='\033[1;31m'
readonly SNS_YELLOW_COLOR='\033[1;33m'
readonly SNS_RESET_COLOR='\033[0m'

# Erroneous Exit Constants
  
  # Invocation Errors   
    readonly SNS_ERR_NO_STORE=5 # The sns store needs to be initialized
    readonly SNS_ERR_NO_OPTS=10 # No mode argument was specified
    readonly SNS_ERR_NS_ARGS=11 # The specified mode requires an argument
  
  # Dependency Errors
    readonly SNS_ERR_DEPS=20   # Base error - add the following codes
    readonly SNS_ERR_NO_gpg2=1  # GPG is not installed 
    readonly SNS_ERR_NO_tree=2 # Tree is not installed
    readonly SNS_ERR_NO_git=3  # Git is not installed
    
# Global Variables
typeset -i SNS_SID="$RANDOM"
typeset -a SNS_ACTION=("")
typeset -a MISSING_DEPS
typeset -i SNS_EXIT=0
declare    SNS_PUBKEY= 

# Function Definitions
# sns_printError     Prints an error message
# sns_NoteHeader     Prints standard note header to stdout
# sns_checkDeps      Checks the system for required dependencies
# sns_checkStore     Checks if $SNS_STORE exists
# sns_sanityCheck    Wrapper for sns_checkDeps and sns_checkStore
# ----
# sns_initStore      Initializes the SNS Store                             ( -i)
# sns_printHelp      Prints help page                                      ( -h)
# sns_list           Lists all notes in `tree` format                      (  *)
# sns_create         Creates note; calls sns_edit()                        ( -c)
# sns_edit           Decrypts note to /tmp, calls editor, re-encrypts note ( -e)
# sns_print          Prints note to stdout                                 ( -p)
# sns_rm             Deletes note from store                               ( -d)
# sns_gitPassthrough Passes through all instructions to git                (git)

function sns_printError(){
  printf "$SNS_RED_COLOR!$SNS_RESET_COLOR - %s\n" "$@"
}
function sns_NoteHeader(){
  printf "%s\n%s\n" "Title:" "Date:"
}
function sns_checkDeps(){
  local SNS_RETURN="true";
  for DEP in "${SNS_DEPS[@]}"; do
    if test  ! -e "$(which "$DEP" 2>/dev/null)"; then
      MISSING_DEPS+=("$DEP")
      SNS_RETURN="false";
    fi
  done
  "$SNS_RETURN";
}
function sns_checkStore(){
  if [ -d "$SNS_STORE" ]; then true; else false; fi
}
function sns_sanityCheck {
  if ! sns_checkDeps; then
    SNS_EXIT="$SNS_ERR_DEPS"
    for DEP in "${MISSING_DEPS[@]}"; do
      local SNS_DEP_EC="\$ERR_NO_$DEP"
      printError "Dependency %s not in path." "$DEP";
      SNS_EXIT+=${!SNS_DEP_EC}
    done
  fi
  
  if [ -r "$SNS_STORE/.pubkey" ]; then
    SNS_PUBKEY="$(cat "$SNS_STORE/.pubkey")"
  elif ! sns_checkStore; then
    if [ "$(echo "${SNS_ACTION[@]}" | awk '{print $1;}')" != "sns_initStore" ]; then
      printError "The sns store does not exist."
      printf "  - %s\n" "Please run \`sns -i [gpg-key]\` to initialize sns."
      SNS_EXIT="$SNS_ERR_NO_STORE"
    fi
  fi
}
#----
function sns_initStore {
  mkdir -p "$SNS_STORE"
  echo "$@" | awk '{print $1}' > "$SNS_KEYFILE"
}
function sns_printHelp(){
    printf "%s" "usage: sns [-cedlp] <notebook/section/name>"
    printf "\n%s%s%s" "usage: sns " "git" " ..."
    printf "\n%s" "       sns [-hi]"

    printf "\n%s" "  -c | --create : Create note"
    printf "\n%s" "  -C | --config : Edit Config"
    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 SNS store"
    printf "\n%s" "  -l | --list   : List all notes in NOTEBOOK"
    printf "\n%s" "  -p | --print  : Print note to console"
    printf "\n\n"
}
function sns_list(){
  # Change directories to fix tree header
    cd "$SNS_STORE" || exit; cd .. || exit;
  # Print the tree
    tree -C --noreport --prune "$(echo "$@" | awk '{print $1}')"
}
function sns_create(){
  # Make sure the note doesn't already exist
    if [ -r "$SNS_STORE/$(echo "$@" | awk '{print $1}')" ]; then 
      sns_printError "Note already exists."
      return
    fi
  
  # Print the standard header to a temporary note
    sns_NoteHeader > /tmp/"$SNS_SID" 
  
  # Edit the new note
    sns_edit "$(echo "$@" | awk '{print $1}')"
}
function sns_edit(){
  # Make the function more readable
    local readonly SNS_NOTE="$SNS_STORE/$(echo "$@" | awk '{print $1}')"

  # Test if edit was called from create
    if [ ! -r /tmp/"$SNS_SID" ]; then gpg2 -d  -o /tmp/"$SNS_SID" "$SNS_NOTE"; fi
    
  # Edit the note
    vim /tmp/"$SNS_SID"

  # Make sure the notebook/section exists
    if [ ! -d "$(dirname "$SNS_NOTE")" ]; then mkdir -p "$(dirname "$SNS_NOTE")"; fi
  
  # If the note previously existed, make a backup.
    if [ -r "$SNS_NOTE" ]; then mv "$SNS_NOTE" "$SNS_NOTE.bk"; fi
      
  # Re-encrypt it to the store
    gpg2 -r "$SNS_PUBKEY" -o "$SNS_NOTE" -e /tmp/"$SNS_SID"
  
  # If all went well, remove the backup
    if [ -r "$SNS_NOTE" ]; then rm "$SNS_NOTE.bk"; fi
}
function sns_print(){
  gpg2 -d "$SNS_STORE/$(echo "$@" | awk '{print $1}')"
}
function sns_rm(){
  rm -f "$SNS_STORE/$(echo "$@" | awk '{print $1}')"
}
function sns_gitPassthrough(){
  cd "$SNS_STORE" || exit;
  git "$@";
}
# ----
function sns_argParse(){
  ARGS=($@)
  #echo "${#ARGS}"
  SNS_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 "$SNS_ERR_NS_ARGS"
    case "${ARGS[!OPTIND]}" in 
      -i|-c|-e|-p|-d)
        if [ "${#ARGS}" -lt 2 ]; then
          printError "A required argument was not given."
          SNS_EXIT="$SNS_ERR_NS_ARGS"
          return
        fi
    esac
    case "$OPT" in
      i)
        SNS_ACTION=("sns_initStore" "$OPTARG");;
      h)
        SNS_ACTION=("sns_printHelp");;
      c)
        SNS_ACTION=("sns_create $OPTARG");;
      e)
        SNS_ACTION=("sns_edit $OPTARG");;
      p)
        SNS_ACTION=("sns_print $OPTARG");;
      d)
        SNS_ACTION=("sns_rm $OPTARG");;
    esac
  done
  
  if [ "${#SNS_ACTION[@]}" -eq 0 ]; then
    if [ "$(echo "$@" | awk '{print $1}')" == "git" ]; then
      SNS_ACTION=($@)
    else
      if [ -d "$SNS_STORE/$*" ]; then
        SNS_ACTION=("sns_list" "sns/$@")
      else
        SNS_ACTION=("sns_list" "sns")
      fi
    fi
  fi
}

# Entry Point
printf "%s\n%s\n" "$XL_PRODUCT" "$XL_VER"
printf "\n"

sns_argParse "$@"
sns_sanityCheck
if [ "$SNS_EXIT" -eq 0 ]; then
  eval "${SNS_ACTION[@]}"
fi

printf "\n"

exit "$SNS_EXIT"