#!/usr/bin/env bash

# CONSTANTS

BASEDIR=$(dirname "$0")
MIAOU_IMAGE=images:debian/13
APT_ARCHIVES=/var/cache/apt/archives
PROJECT_SANDBOX=sandbox
TEMPLATE_SANDBOX=miaou-debian13-template
TEMPLATE_REFRESH_DELAY="7 days"

CONTAINER=

# FUNCTIONS

function usage {
    echo "$(basename "$0") <CONTAINER_NAME>"
}

function humanize_ago {
    local seconds=$(($(date +%s) - $(date -d "$1" +%s)))

    local days=$((seconds / 86400))
    local hours=$(((seconds % 86400) / 3600))
    local minutes=$(((seconds % 3600) / 60))

    if ((days > 365)); then
        echo "$((days / 365)) year(s) ago"
    elif ((days > 30)); then
        echo "$((days / 30)) month(s) ago"
    elif ((days > 0)); then
        echo "$days day(s) ago"
    elif ((hours > 0)); then
        echo "$hours hour(s) ago"
    elif ((minutes > 0)); then
        echo "$minutes minute(s) ago"
    else
        echo "$seconds second(s) ago"
    fi
}

function parse_options {
    while [[ $# -gt 0 ]]; do
        case "$1" in
            --help | -h)
                usage && exit 0
                ;;
            *)
                if [[ -z $CONTAINER ]]; then
                    CONTAINER=$1
                else
                    echo >&2 "Unknown option: $1" && usage && exit 2
                fi
                ;;
        esac

        shift 1 # Move to the next argument
    done
    [[ -n $CONTAINER ]] || (usage && exit 1)
}

function create {
    incus --project "$PROJECT_SANDBOX" copy "$TEMPLATE_SANDBOX" "$CONTAINER" --target-project $(incus project get-current)
    incus file delete "$CONTAINER/etc/machine-id"
    incus start "$CONTAINER"
    customize_host "$CONTAINER"
}

function mount_miaou_bash {
    [[ -v MIAOU_BASH_DIR ]] && echo >&2 "Warn: variable MIAOU_BASH_DIR missing!" && return
    local target="$1"
    local optional_project=${2:-}
    [[ -n $optional_project ]] && optional_project="--project $optional_project"
    incus $optional_project config device add $target MIAOU-BASH disk source=$MIAOU_BASH_DIR path=/opt/miaou-bash readonly=true | grep -q 'Device MIAOU-BASH added'
    incus $optional_project config set $target environment.PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/miaou-bash/tools
}

function build_sandbox_project {
    incus project show $PROJECT_SANDBOX > /dev/null || incus project create $PROJECT_SANDBOX
}

function refresh_template {
    incus --project "$PROJECT_SANDBOX" start "$TEMPLATE_SANDBOX"
    incus --project "$PROJECT_SANDBOX" exec "$TEMPLATE_SANDBOX" -- bash << EOF
        apt-get update
        apt-get dist-upgrade -y
        apt-get install -y curl
	    /opt/miaou-bash/install.sh
EOF
    incus --project "$PROJECT_SANDBOX" stop "$TEMPLATE_SANDBOX"
    local image_date=$(incus --project "$PROJECT_SANDBOX" list "$TEMPLATE_SANDBOX" -f compact,noheader -cl)
    echo "template refreshed at: $image_date"
}

function build_template_from_scratch {
    build_sandbox_project
    echo "building image from scratch..."
    incus --project "$PROJECT_SANDBOX" file delete "$TEMPLATE_SANDBOX"/etc/apt/sources.list
    incus --project "$PROJECT_SANDBOX" file push --uid 0 --gid 0 --mode 644 --create-dirs /etc/apt/sources.list.d/debian.sources "$TEMPLATE_SANDBOX"/etc/apt/sources.list.d/debian.sources
    cat << EOF | incus --project "$PROJECT_SANDBOX" file push --uid 0 --gid 0 --mode 644 --create-dirs - "$TEMPLATE_SANDBOX"/etc/systemd/resolved.conf.d/10-disable-ipv4-listener.conf
[Resolve]
LLMNR=no
DNSStubListener=no
EOF
    mount_miaou_bash "$TEMPLATE_SANDBOX" "$PROJECT_SANDBOX"

    incus --project "$PROJECT_SANDBOX" create "$MIAOU_IMAGE" "$TEMPLATE_SANDBOX"
    refresh_template
    echo "image:"$TEMPLATE_SANDBOX" from project:$PROJECT_SANDBOX built successfully!"
}

function prepare_template_for_quick_creation {
    local image_date=$(incus list "$TEMPLATE_SANDBOX" -f compact,noheader -cl --project "$PROJECT_SANDBOX")
    if [[ -z $image_date ]]; then
        build_template_from_scratch
    else
        local true_date=$(date -d "$image_date" +%s)
        local expiration_date=$(date -d "$TEMPLATE_REFRESH_DELAY ago" +%s)
        if ((true_date < expiration_date)); then
            echo "template exists $(humanize_ago "$image_date"), needs a refresh..."
            refresh_template
        else
            :
            # echo "template already exists $(humanize_ago "$image_date")!"
        fi
    fi
}

function customize_host {
    local target="$1"
    local domain=$(incus network get incusbr0 dns.domain)
    domain=${domain:-incus}
    cat << EOF | incus file push --uid 0 --gid 0 --mode 644 --create-dirs - $target/etc/hosts
127.0.1.1	$target.$domain $target
127.0.0.1	localhost
EOF
}

function assert_not_sandboxing {
    [[ $(incus project get-current) == "$PROJECT_SANDBOX" ]] \
        && echo ERROR: actual sandboxing project, please switch back to your 'default' project >&2 \
        && exit 30 \
        || true
}

# MAIN

set -Eue
parse_options "$@"

assert_not_sandboxing
prepare_template_for_quick_creation
create
echo Success