#!/usr/bin/env bash

year="$(date '+%Y')"
usage="Usage: $0 <command> [-r <remote>] [-y <year>]"

print_help() {
    cat << EOF
$usage

Description:
  This script synchronizes files using rsync

Options:
  -r <remote>    Specify the target machine (nest, lnest, laptop, roost).
  -y <year>      Specify the year for data synchronization.
  -h             Display this help message and exit.

commands:
  push           Push data to the specified target.
  pull           Pull data from the specified target.

Examples:
  $0 push -r roost -y 2023     # Push data to the 'roost' target for the year 2023.
  $0 pull -r nest              # Pull data from the 'nest' target for the current year ($year).
EOF
}

check_requirements(){
     if ! command -v rsync > /dev/null; then
        echo "Missing rsync, exiting"
        exit 1
    fi
}

find_local(){
    case "$(uname)" in
        "Linux")
            local_dir="$HOME/doc/edu"
            ;;
        "Darwin")
            local_dir="$HOME/Documents"
            ;;
        *)
            exit 1
    esac
    echo "$local_dir"
}

find_remote(){
    case "$1" in
        "nest"|"lnest")
            echo "$1:doc/edu"
            ;;
        "laptop"|"macbook")
            echo "laptop:Documents"
            ;;
        "roost")
            echo "eduroost:doc"
            ;;
        *)
            exit 1
    esac
}

push_data(){
    local lroot="$1"
    rsync -aiuvzCP --exclude-from="$lroot/.syncignore" "$lroot/$year" "$remote_root"
}

pull_data(){
    local lroot="$1"
    rsync -aiuvzCP "$remote_root/$year" "$lroot"
}

check_requirements

# set command to first argument
command="$1"
[ -z "$command" ] && {
    echo "missing command"
    echo "$usage"
    exit 1
}
shift

# parse options
while getopts ":r:y:h" opt; do
    case $opt in
        r) remote="$OPTARG";;
        y) year="$OPTARG";;
        h) print_help; exit 0 ;;
        \?)
            echo "Invalid options: -$OPTARG" >&2
            exit 1
            ;;
        :)
            echo "Option -$OPTARG requires an argument" >&2
            exit 1
            ;;
    esac
done


# check for valid remote
[ -z "$remote" ] && {
    echo "$usage" >&2
    exit 1
}

# set remote root
remote_root="$(find_remote "$remote")"
[ -z "$remote_root" ] && {
    echo "Unrecognized remote: $remote"
    exit 1
}

local_root="$(find_local)"
[ -z "$local_root" ] && {
    echo "Machine not recognized, exitting"
    exit 1
}

# execute commands
case "$command" in 
    "push") push_data "$local_root";;
    "pull") pull_data "$local_root";;
    "help") print_help ;;
    *)
        echo "unrecognized command: $command"
        exit 1
esac