#!/usr/bin/env bash

if [[ -n $ZIO_HELPERS_DIR ]] && [[ -d $ZIO_HELPERS_DIR ]]; then
    . "$ZIO_HELPERS_DIR/bash.sh"
else
  if [[ "$(realpath "$(dirname "$(realpath -s "$0")")/../../../")" == "/" ]]; then
      . /usr/local/libexec/zio/helpers/bash.sh
  else
      . "$(dirname "$(realpath -s "$0")")/../libexec/zio/helpers/bash.sh"
  fi
fi

me_filename="$(basename "$(realpath -s "$0")")"
backup_scripts_dir="$(get_config_dir "sh.zio.backup")/scripts"
cache_dir="$(get_config_dir "sh.zio.backup" "/var/cache")/restic"
secrets_dir="$(get_config_dir "sh.zio.backup")/secrets"
host="$(hostname -s)"
now="$(date +"%Y-%m-%d %H:%M:%S")"
restic_mount_path="/mnt/restic"
restic_path=""
restic_repo_file="$secrets_dir/restic-repo"
restic_repo_passwd_file="$secrets_dir/restic-repo-passwd"
restic_version="0.16.0"

function download_restic() {
    restic_version="$1"

    restic_download_url="https://github.com/restic/restic/releases/download/v${restic_version}/restic_${restic_version}_linux_amd64.bz2"
    restic_path="/tmp/restic-v$restic_version"
    restic_archive_path="${restic_path}_$(date +%s).${restic_download_url##*.}"

    if [[ ! -f "$restic_path" ]]; then
        say info "Downloading Restic ($restic_version)..."

        curl -L -s -o "$restic_archive_path" "$restic_download_url"
        bzip2 -dc "$restic_archive_path" > "$restic_path"
        rm -f "$restic_archive_path"

        chmod +x "$restic_path"

        if [[ ! "$(echo "$("$restic_path" version)")" == "restic $restic_version"* ]]; then
            die "Unexpected output from '$restic_path version'"
            rm -f "$restic_path"
        fi
    fi
}

function invoke_restic() {
    command="$1"
    args="${@:2}"

    case "$(cat "$restic_repo_file")" in
        "/"*)
            if [[ ! -d "$(cat "$restic_repo_file")" ]]; then
                say warning "'$(cat "$restic_repo_file")' does not exist. Creating directory..."
                mkdir -p "$(cat "$restic_repo_file")"
            fi
            ;;
        "b2"*)
            b2_account_id_file="$secrets_dir/b2-account-id"
            b2_account_key_file="$secrets_dir/b2-account-key"

            test_file "$b2_account_id_file"
            test_file "$b2_account_key_file"

            export B2_ACCOUNT_ID="$(cat "$b2_account_id_file")"
            export B2_ACCOUNT_KEY="$(cat "$b2_account_key_file")"
            ;;
        *)
            die "Repository unsupported ("$(cat "$restic_repo_file")")"
            ;;
    esac

    if [[ -z $command ]]; then
        say warning "No command specified. Not running"
    elif [[ $command == "generate" || $command == "self-update" ]]; then
        say warning "Unsupported command: $command"
    else
        attempts=10
        attempts_delay=600

        while true; do
            "$restic_path" \
                --cache-dir "$cache_dir" \
                --password-file "$restic_repo_passwd_file" \
                --repo "$(cat $restic_repo_file)" \
                $command $args

            if [[ $? == 0 ]]; then
                break
            else
                if [[ $attempts == 0 ]]; then
                    say warning "Command failed. No attempts left"
                    break
                else
                    attempts=$((attempts - 1))
                    say warning "Command failed. Trying again in $attempts_delay seconds ($attempts attempts remaining)..."
                    sleep $attempts_delay
                fi
            fi
        done
    fi
}

function invoke_script() {
    backup_script="$1"

    backup_script_filename="$(basename "$backup_script")"
    backup_script_name="${backup_script_filename%.*}"
    backup_script_name_length="${#backup_script_name}"

    say primary "-[$backup_script_name]$(repeat "-" $((80-3-$backup_script_name_length)))"
    chmod +x "$backup_script"

    export -f backup_dir
    export -f backup_dumps
    export -f backup_files
    export -f create_tmp_file
    export -f die
    export -f forget_backup
    export -f get_config_dir
    export -f get_dump_dir
    export -f get_real_path
    export -f get_secret
    export -f invoke_restic
    export -f podman_exec
    export -f prune_backup
    export -f prune_dumps
    export -f say
    export -f start_service
    export -f stop_service
    export -f test_file
    export backup_scripts_dir
    export cache_dir
    export host
    export me_filename
    export now
    export restic_repo_file
    export restic_repo_passwd_file
    export restic_path
    export secrets_dir

    "$backup_scripts_dir/$backup_script_filename"
}

function backup_files() {
    patterns="$1"
    args="${@:2}"
    files_from_path="$(create_tmp_file "files-from")"

    echo "$patterns" > "$files_from_path"
    sed -i -e 's/:/\n/g' "$files_from_path"

    say info "Backing up: $patterns ➔ $(cat $restic_repo_file)"

    invoke_restic \
        backup \
        --files-from "$files_from_path" \
        --iexclude "__MACOSX" \
        --iexclude ".cache" \
        --iexclude ".DS_Store" \
        --iexclude "cache" \
        --iexclude "CachedData" \
        --iexclude "CachedExtensionVSIXs" \
        --iexclude "Code Cache" \
        --iexclude "GPUCache" \
        --iexclude "GrSharedCache" \
        --iexclude "ShaderCache" \
        --iexclude "system-cache" \
        --iexclude "thumbs.db" \
        --iexclude "tmp" \
        --exclude "containers/storage/overlay" \
        --exclude "containers/storage/overlay-containers" \
        --exclude "containers/storage/overlay-images" \
        --exclude "containers/storage/overlay-layers" \
        --exclude-if-present ".nobackup" \
        --host "$host" \
        --tag "$me_filename" \
        --tag "$(basename "$0")" \
        $args "/"

    rm -f "$files_from_path"
}

function backup_dir() {
    path="$1"
    args="${@:2}"

    if [[ ! -d "$path" ]]; then
        say warning "'$path' does not exist. Not backing up"
    else
        backup_files "$path" $args
    fi
}

function backup_dumps() {
    service="$1"
    service_dumps_dir="/srv/dumps/$host/$service"
    backup_dir "$service_dumps_dir"

    if [[ $? == 0 ]]; then
        rm -rf "$service_dumps_dir"
        prune_dumps
    fi
}

function forget_backup() {
    timeframe="$1"

    if [[ -z $timeframe ]]; then
        timeframe="0y0m7d0h"
    fi

    say info "Forgetting: $timeframe ($host)"

    invoke_restic \
        forget \
        --compact \
        --keep-within "$timeframe" \
        --host "$host"
}

function prune_backup() {
    say info "Pruning"

    invoke_restic \
        prune \
        --dry-run
}

function prune_dumps() {
    [[ -z "$(ls -A "/srv/dumps/$host")" ]] && rm -rf "/srv/dumps/$host"
    [[ -z "$(ls -A "/srv/dumps")" ]] && rm -rf "/srv/dumps"
}

function get_dump_dir() {
    service="$1"

    specific_dumps_dir="/srv/dumps/$host/$service/$(date +"%Y%m%d%H%M%S")"
    mkdir -p "$specific_dumps_dir"
    [[ $? == "0" ]] && echo "$specific_dumps_dir"
}

function get_secret() {
    secret_path="$secrets_dir/$1"

    if [[ -f "$secret_path" ]]; then
        cat "$secret_path"
    fi
}

function start_service() {
    service="$1"

    say info "Starting service: $service"
    systemctl start $service
}

function stop_service() {
    service="$1"

    say info "Stopping service: $service"
    systemctl stop $service
}

if [[ "$@" == "help" ]]; then
    echo "$me_filename

Usage:
    $me_filename
        Run all backup scripts available in $backup_scripts_dir

    $me_filename <script>
        Run a specific script from a given path

    $me_filename rescue <snapshot-ID>
        Restore <snapshot-ID> to /srv/dumps/$host/restic/<snapshot-ID>

    $me_filename toggle-mount
        Mount (or unmount) restic to /mnt/restic

    $me_filename <command> [arguments]
        Execute restic with arbitrary commands and optional arguments.
        This command is bootstrapped with some arguments — which are not
        overridable — as follows:
          * --cache-dir
          * --password-file
          * --repo

    $me_filename help
        Output this usage text. Use '--help' or 'help <command>' to output
        restic's help text
"
    exit 0
fi

test_root
test_prog "bzip2"
test_prog "curl"
test_prog "grep"
test_prog "hostname"

mkdir -p "$backup_scripts_dir"
mkdir -p "$cache_dir"
mkdir -p "$secrets_dir"

chmod -R 711 "$secrets_dir"

download_restic $restic_version

test_file "$restic_repo_file"
test_file "$restic_repo_passwd_file"

if [[ -z "$1" || -f "$1" ]]; then
    if [[ -z "$1" ]]; then
        say info "Running backup scripts..."

        if ! [[ "$(ls -A $backup_scripts_dir)" ]]; then
            die "No scripts found in '$backup_scripts_dir'"
        fi

        for backup_script in $backup_scripts_dir/*; do
            invoke_script $backup_script
        done
    else
        say info "Running script: $(basename "$1")"
        invoke_script "$1"
    fi

    say primary "$(repeat "-" 80)"

    invoke_restic snapshots \
        --compact \
        --latest 1 \
        --host "$host" \
        --tag "$(basename "$0")" \
        | sed -E ":begin;$!N;s/$(basename "$0")\n\s+?//;tbegin;P;D"
elif [[ "$1" == "rescue" ]]; then
    snapshot="$2"
    rescue_dir="/srv/dumps/$host/restic/$snapshot"

    [[ -z "$snapshot" ]] && die "No snapshot ID provided"

    say info "Rescuing: $snapshot (to '$rescue_dir')"

    invoke_restic restore \
        --target "$rescue_dir" \
        "$snapshot"
elif [[ "$1" == "toggle-mount" ]]; then
    function test_restic_mount() {
        mountpoint "$restic_mount_path" &>/dev/null
        echo $?
    }

    mkdir -p "$restic_mount_path"

    if [[ $(test_restic_mount) == 0 ]]; then
        say info "Unmounting: $restic_mount_path"
        umount "$restic_mount_path"

        if [[ $? == 0 ]]; then
            rm -rf "$restic_mount_path"
        else
            die "Failed to unmount (are you still in '$restic_mount_path'?)"
        fi
    else
        say info "Mounting: $restic_mount_path"
        invoke_restic mount "$restic_mount_path" &>/dev/null & disown;

        while true; do
            if [[ $(test_restic_mount) == 0 ]]; then
                exit 0
            fi
        done
    fi
else
    command="$1"
    arguments="${@:2}"

    [[ $command == "purge" ]] && command="prune"

    say info "Running: $restic_path $command $arguments"
    invoke_restic $command $arguments
    exit $?
fi