#!/usr/bin/env bash

SCRIPT_NAME=$(basename "$0")

log_fatal() {
    echo "$SCRIPT_NAME: $*" >&2
    exit 1
}

usage() {
    cat<<EOF
Usage:
    $SCRIPT_NAME list
    $SCRIPT_NAME restore [options] <BACKUP_ID>
    $SCRIPT_NAME help

Commands:
    list                 List available backups
    restore <backup-id>  Restore a backup
    help                 Show this usage message

Restore options:
    --all
    --bluemap
    --fabric
    --fabric-essentials
    --fabric-g4mespeed
    --fabric-world
    --luckperms
    --paper
    --paper-multiverse-inventories
    --paper-essentials
    --paper-plot-squared
    --paper-worlds
    --paper-creative
    --paper-creative-overworld
    --paper-creative-nether
    --paper-survival
    --paper-survival-overworld
    --paper-survival-nether
    --paper-survival-the-end
    --schematics
    --velocity
    --velocity-dclink

Examples:
    $SCRIPT_NAME list
    $SCRIPT_NAME restore --fabric 2026-01-20T07-00-49Z
    $SCRIPT_NAME restore --all latest
EOF
}

cmd_list() {
    docker compose run --rm init ls -1 /backups || log_fatal "failed to list backups"
}

cmd_restore() {
    # Cleanup Flags
    CLEANUP_VOLUMES=0

    # Default flags
    ## Bluemap
    RESTORE_BLUEMAP=0
    ## Fabric server
    RESTORE_FABRIC_ESSENTIALS=0
    RESTORE_FABRIC_G4MESPEED=0
    RESTORE_FABRIC_WORLD=0
    ## LuckPerms
    RESTORE_LUCKPERMS=0
    ## Paper server
    RESTORE_PAPER_MULTIVERSE_INVENTORIES=0
    RESTORE_PAPER_ESSENTIALS=0
    RESTORE_PAPER_PLOT_SQUARED=0
    RESTORE_PAPER_CREATIVE_OVERWORLD=0
    RESTORE_PAPER_CREATIVE_NETHER=0
    RESTORE_PAPER_SURVIVAL_OVERWORLD=0
    RESTORE_PAPER_SURVIVAL_NETHER=0
    RESTORE_PAPER_SURVIVAL_THE_END=0
    ## Schematics
    RESTORE_SCHEMATICS=0
    ## Velocity proxy
    RESTORE_VELOCITY_DCLINK=0

    # Argument parsing
    POS_ARGS=""
    while [ $# -gt 0 ]; do
        case "$1" in
            --all)
                RESTORE_BLUEMAP=1
                RESTORE_FABRIC_ESSENTIALS=1
                RESTORE_FABRIC_G4MESPEED=1
                RESTORE_FABRIC_WORLD=1
                RESTORE_LUCKPERMS=1
                RESTORE_PAPER_MULTIVERSE_INVENTORIES=1
                RESTORE_PAPER_ESSENTIALS=1
                RESTORE_PAPER_PLOT_SQUARED=1
                RESTORE_PAPER_CREATIVE_OVERWORLD=1
                RESTORE_PAPER_CREATIVE_NETHER=1
                RESTORE_PAPER_SURVIVAL_OVERWORLD=1
                RESTORE_PAPER_SURVIVAL_NETHER=1
                RESTORE_PAPER_SURVIVAL_THE_END=1
                RESTORE_SCHEMATICS=1
                RESTORE_VELOCITY_DCLINK=1
                ;;

            --bluemap)
                RESTORE_BLUEMAP=1
                ;;

            --fabric)
                RESTORE_FABRIC_ESSENTIALS=1
                RESTORE_FABRIC_G4MESPEED=1
                RESTORE_FABRIC_WORLD=1
                ;;

            --fabric-essentials)
                RESTORE_FABRIC_ESSENTIALS=1
                ;;

            --fabric-g4mespeed)
                RESTORE_FABRIC_G4MESPEED=1
                ;;

            --fabric-world)
                RESTORE_FABRIC_WORLD=1
                ;;

            --luckperms)
                RESTORE_LUCKPERMS=1
                ;;

            --paper)
                RESTORE_PAPER_MULTIVERSE_INVENTORIES=1
                RESTORE_PAPER_ESSENTIALS=1
                RESTORE_PAPER_PLOT_SQUARED=1
                RESTORE_PAPER_CREATIVE_OVERWORLD=1
                RESTORE_PAPER_CREATIVE_NETHER=1
                RESTORE_PAPER_SURVIVAL_OVERWORLD=1
                RESTORE_PAPER_SURVIVAL_NETHER=1
                RESTORE_PAPER_SURVIVAL_THE_END=1
                ;;

            --paper-multiverse-inventories)
                RESTORE_PAPER_MULTIVERSE_INVENTORIES=1
                ;;

            --paper-essentials)
                RESTORE_PAPER_ESSENTIALS=1
                ;;

            --paper-plot-squared)
                RESTORE_PAPER_PLOT_SQUARED=1
                ;;

            --paper-worlds)
                RESTORE_PAPER_CREATIVE_OVERWORLD=1
                RESTORE_PAPER_CREATIVE_NETHER=1
                RESTORE_PAPER_SURVIVAL_OVERWORLD=1
                RESTORE_PAPER_SURVIVAL_NETHER=1
                RESTORE_PAPER_SURVIVAL_THE_END=1
                ;;

            --paper-creative)
                RESTORE_PAPER_CREATIVE_OVERWORLD=1
                RESTORE_PAPER_CREATIVE_NETHER=1
                ;;

            --paper-creative-overworld)
                RESTORE_PAPER_CREATIVE_OVERWORLD=1
                ;;

            --paper-creative-nether)
                RESTORE_PAPER_CREATIVE_NETHER=1
                ;;

            --paper-survival)
                RESTORE_PAPER_SURVIVAL_OVERWORLD=1
                RESTORE_PAPER_SURVIVAL_NETHER=1
                RESTORE_PAPER_SURVIVAL_THE_END=1
                ;;

            --paper-survival-overworld)
                RESTORE_PAPER_SURVIVAL_OVERWORLD=1
                ;;

            --paper-survival-nether)
                RESTORE_PAPER_SURVIVAL_NETHER=1
                ;;

            --paper-survival-the-end)
                RESTORE_PAPER_SURVIVAL_THE_END=1
                ;;

            --schematics)
                RESTORE_SCHEMATICS=1
                ;;

            --velocity)
                RESTORE_VELOCITY_DCLINK=1
                ;;

            --velocity-dclink)
                RESTORE_VELOCITY_DCLINK=1
                ;;

            --help)
                usage
                exit 0
                ;;

            *)
                POS_ARGS="$POS_ARGS $1"
                ;;
        esac
        shift
    done

    # Restore positional arguments
    set -- $POS_ARGS

    # Validate and resolve backup id
    [ $# -ge 1 ] || log_fatal "missing backup id"
    [ $# -le 1 ] || log_fatal "unexpected argument: $2"
    BACKUP_ID="$1"
    BACKUP_DIR=$(docker compose run --rm init sh -c '
        TARGET=/backups/"$1"
        if [ ! -e "$TARGET" ]; then
            exit 1
        fi
        # Resolve symlinks to real paths
        REALPATH=$(readlink -f "$TARGET")
        echo "$REALPATH"
    ' -- "$BACKUP_ID") || log_fatal "backup '$BACKUP_ID' not found"
    # Update BACKUP_ID to the actual directory name
    BACKUP_ID=$(basename "$BACKUP_DIR")

    # Validate options
    if [ "$RESTORE_BLUEMAP" -eq 0 ] \
    && [ "$RESTORE_FABRIC_ESSENTIALS" -eq 0 ] \
    && [ "$RESTORE_FABRIC_G4MESPEED" -eq 0 ] \
    && [ "$RESTORE_FABRIC_WORLD" -eq 0 ] \
    && [ "$RESTORE_LUCKPERMS" -eq 0 ] \
    && [ "$RESTORE_PAPER_MULTIVERSE_INVENTORIES" -eq 0 ] \
    && [ "$RESTORE_PAPER_ESSENTIALS" -eq 0 ] \
    && [ "$RESTORE_PAPER_PLOT_SQUARED" -eq 0 ] \
    && [ "$RESTORE_PAPER_CREATIVE_OVERWORLD" -eq 0 ] \
    && [ "$RESTORE_PAPER_CREATIVE_NETHER" -eq 0 ] \
    && [ "$RESTORE_PAPER_SURVIVAL_OVERWORLD" -eq 0 ] \
    && [ "$RESTORE_PAPER_SURVIVAL_NETHER" -eq 0 ] \
    && [ "$RESTORE_PAPER_SURVIVAL_THE_END" -eq 0 ] \
    && [ "$RESTORE_SCHEMATICS" -eq 0 ] \
    && [ "$RESTORE_VELOCITY_DCLINK" -eq 0 ]; then
        log_fatal "no restore options specified"
    fi

    echo "=== Restore started at $(date -u '+%Y-%m-%dT%H:%M:%SZ') ==="
    echo "Restoring from backup: $BACKUP_DIR"

    # Ensure stack is not running
    docker compose down > /dev/null 2>&1

    # Create snapshot to revert to on failure
    trap restore_cleanup_trap HUP INT QUIT ABRT TERM
    create_snapshot || restore_cleanup_failure

    restore_bluemap || restore_cleanup_failure
    restore_fabric || restore_cleanup_failure
    restore_luckperms || restore_cleanup_failure
    restore_paper || restore_cleanup_failure
    restore_schematics || restore_cleanup_failure
    restore_velocity || restore_cleanup_failure

    restore_cleanup_success

    echo "=== Restore completed successfully at $(date -u '+%Y-%m-%dT%H:%M:%SZ') ==="
}

create_snapshot() {
    echo "Creating snapshot..."

    # Map: source volume name -> cloned volume name
    # Source names must match the mount points inside init
    declare -Ag VOLUMES=(
        [bluemap_data]="bluemap_data_$BACKUP_ID"
        [bluemap_maps]="bluemap_maps_$BACKUP_ID"
        [bluemap_web]="bluemap_web_$BACKUP_ID"
        [fabric_data]="fabric_data_$BACKUP_ID"
        [luckperms_data]="luckperms_data_$BACKUP_ID"
        [paper_data]="paper_data_$BACKUP_ID"
        [schematics]="schematics_$BACKUP_ID"
        [velocity_data]="velocity_data_$BACKUP_ID"
    )

    MOUNTS=()
    for VOLUME in "${!VOLUMES[@]}"; do
        MOUNTS+=(-v "${VOLUMES[$VOLUME]}:/backup_$VOLUME")
    done

    # Volumes have started being created
    # Cleanup should delete volumes
    CLEANUP_VOLUMES=1

    for VOLUME in "${VOLUMES[@]}"; do
        docker volume create "$VOLUME" > /dev/null || return 1
    done

    docker compose run --rm \
        "${MOUNTS[@]}" \
        init sh -ec '
           for DIR in \
                bluemap_data \
                bluemap_maps \
                bluemap_web \
                fabric_data \
                luckperms_data \
                paper_data \
                schematics \
                velocity_data
            do
                cp -a --reflink=auto "/$DIR/." "/backup_$DIR"
            done
    ' || return 1

    # Volumes have been successfully cloned
    # Cleanup should restore contents to originals, then delete clones
    CLEANUP_VOLUMES=2

    echo "Created snapshot successfully"
}

restore_bluemap() {
    if [ "$RESTORE_BLUEMAP" -eq "1" ]; then
        echo "Restoring BlueMap data..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/bluemap_data/. /bluemap_data &&
            cp -a --reflink=auto "$1"/bluemap_maps/. /bluemap_maps &&
            cp -a --reflink=auto "$1"/bluemap_web/. /bluemap_web
        ' -- "$BACKUP_DIR" || return 1
    fi
}

restore_fabric() {
    if [ "$RESTORE_FABRIC_ESSENTIALS" -eq 1 ]; then
        echo "Restoring Fabric server's Essentials mod data..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/fabric_data/fabric-essentials.json /fabric_data
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_FABRIC_G4MESPEED" -eq 1 ]; then
        echo "Restoring Fabric server's G4mespeed mod data..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/fabric_data/g4mespeed /fabric_data
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_FABRIC_WORLD" -eq 1 ]; then
        echo "Restoring Fabric server's world..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/fabric_data/world /fabric_data
        ' -- "$BACKUP_DIR" || return 1
    fi
}

restore_luckperms() {
    if [ "$RESTORE_LUCKPERMS" -eq 1 ]; then
        echo "Restoring LuckPerms database..."

        docker compose up --wait luckperms > /dev/null 2>&1

        docker compose exec -T luckperms sh -c '
            psql -U luckperms postgres -c "DROP DATABASE IF EXISTS luckperms;" > /dev/null 2>&1 &&
            psql -U luckperms postgres -c "CREATE DATABASE luckperms OWNER luckperms;" > /dev/null 2>&1 &&
            psql -U luckperms luckperms < "$1"/luckperms.sql > /dev/null 2>&1
        ' -- "$BACKUP_DIR" || return 1
    fi
}

restore_paper() {
    if [ "$RESTORE_PAPER_MULTIVERSE_INVENTORIES" -eq 1 ]; then
        echo "Restoring Paper server's Multiverse-Inventories plugin data..."
        docker compose run --rm init sh -c '
            mkdir -p /paper_data/plugins &&
            chown minecraft_server:minecraft_server /paper_data/plugins &&
            cp -a --reflink=auto "$1"/paper_data/plugins/Multiverse-Inventories /paper_data/plugins
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_PAPER_ESSENTIALS" -eq 1 ]; then
        echo "Restoring Paper server's Essentials plugin data..."
        docker compose run --rm init sh -c '
            mkdir -p /paper_data/plugins &&
            chown minecraft_server:minecraft_server /paper_data/plugins &&
            cp -a --reflink=auto "$1"/paper_data/plugins/Essentials /paper_data/plugins
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_PAPER_PLOT_SQUARED" -eq 1 ]; then
        echo "Restoring Paper server's PlotSquared plugin data..."
        docker compose run --rm init sh -c '
            mkdir -p /paper_data/plugins &&
            chown minecraft_server:minecraft_server /paper_data/plugins &&
            cp -a --reflink=auto "$1"/paper_data/plugins/PlotSquared /paper_data/plugins
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_PAPER_CREATIVE_OVERWORLD" -eq 1 ]; then
        echo "Restoring Paper server's creative overworld..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/paper_data/creative /paper_data
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_PAPER_CREATIVE_NETHER" -eq 1 ]; then
        echo "Restoring Paper server's creative nether..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/paper_data/creative_nether /paper_data
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_PAPER_SURVIVAL_OVERWORLD" -eq 1 ]; then
        echo "Restoring Paper server's survival overworld..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/paper_data/survival /paper_data
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_PAPER_SURVIVAL_NETHER" -eq 1 ]; then
        echo "Restoring Paper server's survival nether..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/paper_data/survival_nether /paper_data
        ' -- "$BACKUP_DIR" || return 1
    fi

    if [ "$RESTORE_PAPER_SURVIVAL_THE_END" -eq 1 ]; then
        echo "Restoring Paper server's survival the end..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/paper_data/survival_the_end /paper_data
        ' -- "$BACKUP_DIR" || return 1
    fi
}

restore_schematics() {
    if [ "$RESTORE_SCHEMATICS" -eq 1 ]; then
        echo "Restoring WorldEdit schematics..."
        docker compose run --rm init sh -c '
            cp -a --reflink=auto "$1"/schematics/. /schematics
        ' -- "$BACKUP_DIR" || return 1
    fi
}

restore_velocity() {
    if [ "$RESTORE_VELOCITY_DCLINK" -eq 1 ]; then
        echo "Restoring Velocity proxy's dclink database..."
        docker compose run --rm init sh -c '
            mkdir -p /velocity_data/plugins/dclink-velocity &&
            chown minecraft_server:minecraft_server /velocity_data/plugins &&
            chown minecraft_server:minecraft_server /velocity_data/plugins/dclink-velocity &&
            cp -a --reflink=auto "$1"/velocity_data/plugins/dclink-velocity/dclink.db /velocity_data/plugins/dclink-velocity
        ' -- "$BACKUP_DIR" || return 1
    fi
}

restore_cleanup_success() {
    CLEANUP_VOLUMES=1
    restore_cleanup
}

restore_cleanup_trap() {
    restore_cleanup
    echo "=== Restore cancelled at $(date -u '+%Y-%m-%dT%H:%M:%SZ') ==="
    exit 0
}

restore_cleanup_failure() {
    restore_cleanup
    echo "=== Restore completed unsuccessfully at $(date -u '+%Y-%m-%dT%H:%M:%SZ') ==="
    exit 1
}

restore_cleanup() {
    # Ignore specified conditions to ensure cleanup runs to completion uninterrupted
    trap '' HUP INT QUIT ABRT TERM

    echo "Running cleanup..."

    docker compose down > /dev/null 2>&1

    if [ "$CLEANUP_VOLUMES" -ge "2" ]; then
        echo "Reverting to snapshot..."
        docker compose run --rm \
            "${MOUNTS[@]}" \
            init sh -ec '
                for DIR in \
                    bluemap_data \
                    bluemap_maps \
                    bluemap_web \
                    fabric_data \
                    luckperms_data \
                    paper_data \
                    schematics \
                    velocity_data
                do
                    find "${DIR:?}" -mindepth 1 -delete &&
                    cp -a --reflink=auto "/backup_$DIR/." "/$DIR"
                done
        ' || return 1
        echo "Reverted to snapshot successfully"
    fi

    if [ "$CLEANUP_VOLUMES" -ge "1" ]; then
        echo "Removing snapshot..."
        for VOLUME in "${VOLUMES[@]}"; do
            docker volume rm "$VOLUME" > /dev/null 2>&1
        done
        echo "Removed snapshot successfully"
    fi

    echo "Finished cleanup successfully"
}

if [ "$EUID" -ne 0 ]; then
  log_fatal "This command must be run by the root user"
fi

[ $# -ge 1 ] || {
    usage
    log_fatal "expected argument"
}

COMMAND=$1
shift
case "$COMMAND" in
    list)
        cmd_list "$@"
        ;;

    restore)
        cmd_restore "$@"
        ;;

    help)
        usage
        ;;

    *)
        log_fatal "unknown command: $COMMAND"
        ;;
esac