#!/bin/sh
# Note taking script

NOTES_DIR="$HOME/.notes"

# Initialize with the default editor
[ -z "$EDITOR" ] && EDITOR="/usr/bin/vim"

notes_init() {
    # Check if the notes folder exists, if not, create it
    if [ ! -d $NOTES_DIR ]
    then
        echo -n "Creating notes folder..."
        mkdir -p $NOTES_DIR
        cd $NOTES_DIR
        echo "done."

        git init .
    else
        [ ! -z $1 ] && echo "Notes has already been initialized."
    fi
}

make_title() {
    echo "$*" | sed 's/[^A-Za-z0-9_-]\+/-/g'
}

title_to_name() {
    note_file=$NOTES_DIR/$(make_title $note_arg)
}

check_arg() {
    if [ -z "$note_arg" ]
    then
        echo "Must specify a note title!"
        exit
    fi
}

note_exists() {
    [[ -f "$note_file" ]]
}

check_md5() {
    if [[ "$note_old_md5" == "$note_new_md5" ]]
    then
        echo "No changes to '$note_arg'"

        if [[ ! -z "$1" ]]
        then
            rm -f $1
        fi

        exit
    fi
}

check_dir() {
    if [[ ! -d "$NOTES_DIR" ]]
    then
        echo "Notes not initialized. Run init first!"
        exit
    fi
}

help_cmd() {
    echo '
Note taker for the Command Line
===============================

This is a bash script that lets you take notes which are maintained in a
Git repository. You can run this script by typing the following command
at the command line:

Usage: note <command> <arguments>

Commands
--------

    Command         Usage
    new             Follow this with the note name to create a new note
    edit            Follow this with the note name to edit an existing
                    note
    delete          Follow this with the note name to delete a note
    list            Prints the list of available notes
    hist            Displays the note history
    init            Run this the very first time to set up the folders
    help            Prints this help message
'
}

parse_args() {
    note_cmd=$1
    shift
    note_arg="$*"

    case "$note_cmd" in
    "help")
        help_cmd
        ;;

    "new")
        check_dir
        check_arg
        title_to_name

        if note_exists
        then
            echo "Note '$note_arg' already exists! Use edit instead."
            exit
        fi

        echo "$note_arg" > $note_file
        note_old_md5=$(md5sum $note_file)

        $EDITOR $note_file

        note_new_title=$(head -1 $note_file)
        note_new_md5=$(md5sum $note_file)
        note_new_file=$(make_title $note_new_title)
        check_md5 $note_file

        cd $NOTES_DIR
        gitfile=$(basename $note_new_file)

        git add $gitfile
        git commit -m "Create note '$note_new_title'"
        echo "Created note '$note_new_title'"

        ;;

    "edit")
        check_dir
        check_arg
        title_to_name
        if ! note_exists
        then
            echo "Cannot find note '$note_arg'!"
            exit
        fi

        note_old_title=$(head -1 $note_file)
        note_old_md5=$(md5sum $note_file)

        $EDITOR $note_file

        note_new_title=$(head -1 $note_file)
        note_new_md5=$(md5sum $note_file)

        check_md5

        cd $NOTES_DIR
        gitfile=$(basename $note_file)
        commit_msg="Update note '$note_new_title'"
        if [[ "$note_old_title" != "$note_new_title" ]]
        then
            note_new_file=$(make_title $note_new_title)
            
            git mv $gitfile $note_new_file
            git add $note_new_file
            commit_msg="$commit_msg. Rename from '$note_old_title'"
        else
            git add $gitfile
        fi

        git commit -m "$commit_msg"
        echo "Updated note '$note_new_title'"
        ;;

    "del" | "delete")
        check_dir
        check_arg
        title_to_name
        if ! note_exists
        then
            echo "Cannot find note '$note_arg'!"
            exit
        fi

        cd $NOTES_DIR
        gitfile=$(basename $note_file)
        git rm $gitfile
        git commit -m "Delete note '$note_arg'"
        echo "Deleted note '$note_arg'"
        ;;

    "hist"|"history")
        check_dir
        cd $NOTES_DIR
        git log --pretty=format:'%ai - %s' -- $note_arg
        ;;
    
    "init")
        notes_init warn
        ;;
    
    "list")
        check_dir
        cd $NOTES_DIR
        ls -1 $note_arg
        ;;
    
    *)
        echo "Unrecognized command '$note_cmd'. Use help."
        ;;
    esac
}

parse_args $*