#!/usr/bin/env bash

set -e

DATE_FORMAT="%a, %d %b %Y %H:%M:%S %z"
BASEDIR=~/Notes
EDITOR="${EDITOR:-vim}"

if [ ! -d "$BASEDIR" ]; then
	mkdir -p "$BASEDIR"
fi

die() {
	echo "$@" 1>&2;
	exit 1
}

uuid()
{
	local N B T

	for (( N=0; N < 16; ++N ))
	do
		B=$(( RANDOM%255 ))

		if (( N == 6 ))
		then
			printf '4%x' $(( B%15 ))
		elif (( N == 8 ))
		then
			local C='89ab'
			printf '%c%x' ${C:$(( RANDOM%${#C} )):1} $(( B%15 ))
		else
			printf '%02x' $B
		fi

		for T in 3 5 7 9
		do
			if (( T == N ))
			then
				printf '-'
				break
			fi
		done
	done

	echo
}

canonicalize() {
	NAME="$1"
	NAME="$(echo "$NAME" | tr '[:upper:]' '[:lower:]')"
	NAME="$(echo "$NAME" | sed 's/[^a-z0-9]/_/g')"

	echo "$NAME"
}

utc_timestamp() {
	date -u +"%Y%m%d%H%M%S"
}

find_file_by_id() {
	ID="$1"

	{ grep -l -r -m1 "^X-Note-Id: $ID$" "$BASEDIR" || true; } | sort| head -1
}

assert_find_file_by_id() {
	FILE="$(find_file_by_id "$1")"

	if [ ! -f "$FILE" ]; then
		die "Note with ID <$ID> not found"
	fi

	echo "$FILE"
}

list_entries() {
	FILTER="\
		BEGIN { \
			message_id=0; \
			subject=0; \
			date=0; \
		} \
		match(\$0, /^X-Note-Id: .*$/) { \
				if (message_id != 0) { \
					if (subject !=0 && date != 0)\
						print date, message_id, subject; \
					subject = 0; \
					date = 0; \
				};\
				message_id = substr(\$0, 12, RLENGTH-11); \
		} \
		match(\$0, /^Subject: .*$/) { \
				if (subject != 0) { \
					if (message_id != 0 && date != 0)\
						print date, message_id, subject; \
					message_id = 0; \
					date = 0; \
				}; \
				subject = substr(\$0, 10, RLENGTH-9); \
		} \
		match(\$0, /^X-Date: .*$/) { \
				if (date != 0) { \
					if (message_id != 0 && subject != 0)\
						print date, message_id, subject; \
					subject = 0; \
					message_id = 0; \
				}; \
				date = substr(\$0, 9, RLENGTH-8); \
		} \
		END { \
			if (message_id != 0 && subject != 0 && date != 0)\
				print date, message_id, subject;\
		}\
	"

	grep -r -m 3 -h "^Subject:\|^X-Note-Id:\|^X-Date:" "$BASEDIR" | awk "$FILTER" | sort | cut -d " " -f "2-"
}


new_entry() {
	NAME="$1"
	CANONICAL_NAME="$(canonicalize "$NAME")"
	FULL_NAME="$(utc_timestamp)-$CANONICAL_NAME"
	NOTE_ID="$(uuid)"

	NOTE_DIR="$BASEDIR/$FULL_NAME"
	NOTE_FILE="$NOTE_DIR/note.md"

	mkdir -p "$NOTE_DIR"

	TIMESTAMP=$(date -u +"%Y-%m-%dT%H:%M:%SZ")

	{
		echo "X-Date: $TIMESTAMP"
		echo "X-Note-Id: $NOTE_ID"
		echo "Subject: $NAME"
		echo
	} >> "$NOTE_FILE"

	$EDITOR "$NOTE_FILE"
}

edit_entry() {
	ID="$1"
	FILENAME="$(assert_find_file_by_id "$ID")"

	echo "$FILENAME"

	$EDITOR "$FILENAME"
}

export_note() {
	ID="$1"
	FILENAME="$(assert_find_file_by_id "$ID")"

	DIR="$2"
	if [ -z "$DIR" ]; then
		cat "$FILENAME"
	else
		die "Directory export not implemented"
	fi
}

fzf_entry() {
	NAME="$1"
	ID="$(echo "$2" | cut -d " " -f 1)"

	if [ -z "$ID" ]; then
		if [ ! -z "$NAME" ]; then
			new_entry "$NAME"
		fi
	else
		edit_entry "$ID"
	fi
}

usage() {
  echo "$0 {--new,--list,--edit,--fzf,--help}"
}

while (( "$#" )); do
  case "$1" in
	-n|--new)
	  shift
	  new_entry "$*"
	  exit 0
	  ;;
	-l|--list)
	  list_entries
	  exit 0
	  ;;
	-e|--edit)
	  if [ -z "$2" ]; then
		exit 0
	  fi
	  edit_entry "$2"
	  exit 0
	  ;;
	-f|--fzf)
	  fzf_entry "$2" "$3"
	  exit 0
	  ;;
	-E|--export)
	  if [ -z "$2" ]; then
		echo "Misssing arguments for $1"
		exit 1
	  fi
	  export_note "$2" "$3"
	  exit 0
	  ;;
	-p|--preview)
	  if [ -z "$2" ]; then
		echo "Misssing arguments for $1"
		exit 1
	  fi
	  NOTE_ID="$(echo $2 | cut -d " " -f 1)"
	  export_note "$NOTE_ID" "" | fmt -s -w "$FZF_PREVIEW_COLUMNS"
	  exit 0
	  ;;
	-g|--graph)
	  get_graph
	  exit 0
	  ;;
	*)
	  usage
	  exit 1
	  ;;
  esac

done

usage
exit 1