#!/bin/bash

MIAOU_BASEDIR=$(readlink -f "$(dirname "$0")/..")
readonly MIAOU_BASEDIR

# shellcheck source=/dev/null
. "$MIAOU_BASEDIR/lib/functions.sh"
miaou_init

EXPANDED_CONF="$MIAOU_CONFIGDIR/miaou.expanded.yaml"
NEW_GROUP=lxd
readonly NEW_GROUP EXPANDED_CONF

on_exit() {
    if [ -n "${1:-}" ]; then
        echowarn "Aborted by $1"
    elif [ "${status:-}" -ne 0 ]; then
        echowarn "Failure (status $status)"
    fi
}

function prepare_lxd {
    local PREFIX="lxd:prepare"

    # test group lxd assign to current user
    if ! groups | grep -q lxd; then
        echo "define lxd and assign to user <$USER>"
        sudo groupadd --force "$NEW_GROUP"
        sudo usermod --append --groups "$NEW_GROUP" "$(whoami)"

        realcommand="$MIAOU_BASEDIR/lib/install.sh"
        sg "$NEW_GROUP" -c "EMAIL=$valid_email $realcommand SESSION_RELOAD_REQUIRED $TARGET"

        set +e
        disable_all_signals
        sudo su - "$(whoami)"
        kill -9 "$PPID"
        # no further processing because exec has been called!

    else
        echo "user <$USER> already belongs to group <lxd>!"
    fi

    sudo /opt/miaou-bash/tools/idem_apt_install lxd btrfs-progs

    sudo tee /etc/systemd/system/lxd-containers-restart-on-failure.service &>/dev/null <<EOF
[Unit]
Description=restart lxd containers when no dhclient 
After=lxd.service lxd-containers.service
Requires=lxd.socket
StartLimitInterval=60
StartLimitBurst=5

[Service]
Type=exec

ExecCondition=sh -c '[ \$(lxc list status=running -c4 -fcsv | wc -l) -gt 0 ]] && lxc list status=running -c4 -fcsv | grep -vq eth0'
ExecStart=systemctl restart lxd-containers.service
ExecStartPost=sh -c 'sleep 2 ; [ \$(lxc list status=running -c4 -fcsv | wc -l) -eq 0 ]] || lxc list status=running -c4 -fcsv | grep -q eth0'

Restart=on-failure
RestartSec=10

[Install]
WantedBy=multi-user.target
EOF
    sudo systemctl daemon-reload
}

function configure_lxd {
    local PREFIX="lxd:configure"

    # test lxdbr0 FIXME: preseed too much repetitions!!!!
    if ! lxc network info lxdbr0 &>/dev/null; then

        echo "bridge <lxdbr0> down, so initialization will use default preseed..."

        if [[ $(printenv container) == 'lxc' ]]; then
            echo "--------------------------------"
            echo "nested configuration applying..."
            echo "--------------------------------"
            cat <<EOF | sg $NEW_GROUP -c 'lxd init --preseed'
config: {}
networks:
- name: lxdbr0
  type: bridge
  config:
    ipv4.address: auto
    ipv6.address: none
storage_pools:
- config: {}
  description: ""
  name: default
  driver: dir
profiles:
- config:
    security.privileged: "true"
  description: ""
  devices:
    eth0:
      name: eth0
      nictype: bridged
      parent: lxdbr0
      type: nic
    root:
        path: /
        pool: default
        type: disk    
  name: default
projects: []
cluster: null
EOF
        else
            #empty_block_partition=$(lsblk -o NAME,FSTYPE,GROUP --noheadings -p | grep -E ^.─ | grep disk | awk '{if($3=="") print $1}' | cut -d'/' -f3)
            empty_block_partition=$(lsblk -o NAME,PTTYPE,FSTYPE -ti -P | grep 'PTTYPE="" FSTYPE=""' | head -n1 | cut -d'"' -f2)
            if [[ -n "$empty_block_partition" ]]; then
                echo "--------------------------------"
                echo "use empty block partition /dev/$empty_block_partition for speed and optimization"
                echo "--------------------------------"
                cat <<EOF | sudo lxd init --preseed
config: {}
networks:
- config:
    ipv4.address: auto
    ipv6.address: none
  description: ""
  name: lxdbr0
  type: ""
  project: default
storage_pools:
- config:
    source: /dev/$empty_block_partition
  description: ""
  name: default
  driver: btrfs
profiles:
- config: {}
  description: ""
  devices:
    eth0:
      name: eth0
      network: lxdbr0
      type: nic
    root:
      path: /
      pool: default
      type: disk
  name: default
projects: []
cluster: null
EOF
            else
                echo "--------------------------------"
                echo "use dir partition for development purpose"
                echo "--------------------------------"
                cat <<EOF | lxd init --preseed
config: {}
networks:
- name: lxdbr0
  type: bridge
  config:
    ipv4.address: auto
    ipv6.address: none
storage_pools:
- config: {}
  description: ""
  name: default
  driver: dir
profiles:
- config: {}
  description: ""
  devices:
    eth0:
      name: eth0
      network: lxdbr0
      type: nic
    root:
      path: /
      pool: default
      type: disk
  name: default
projects: []
cluster: null
EOF
            fi
        fi
    else
        echo "bridge <lxdbr0> found implies it has been already initialized!"
    fi

    set_alias 'sameuser' "exec @ARG1@ -- su --whitelist-environment container,container_hostname - $(whoami)"
    set_alias 'login' 'exec @ARGS@ --mode interactive -- /bin/bash -c $@${user:-root} - exec su --whitelist-environment container,container_hostname - '
    set_alias 'll' 'list -c ns4mDN'

    # test environment container hostname
    local env_container_hostname
    env_container_hostname=$(sg $NEW_GROUP -c 'lxc profile get default environment.container_hostname')
    if [[ -z "$env_container_hostname" ]]; then
        env_container_hostname=$(hostname -s)
        if env | grep -q container_hostname; then
            local previous_container_hostname
            previous_container_hostname=$(env | grep container_hostname | cut -d '=' -f2)
            env_container_hostname="$previous_container_hostname $env_container_hostname"
        fi

        echo -n "set environment container_hostname to <$env_container_hostname> ... "
        sg $NEW_GROUP -c "lxc profile set default environment.container_hostname \"$env_container_hostname\""
        PREFIX="" echoinfo DONE
    else
        echo "environment container_hostname <$env_container_hostname> already defined!"
    fi

    if ! grep -q "root:$(id -u):1" /etc/subuid; then
        echo -n "saving subuid, subgid permissions for <$(whoami)> ..."
        printf "root:$(id -u):1\n" | sudo tee -a /etc/subuid /etc/subgid &>/dev/null
        PREFIX="" echoinfo DONE
    else
        echo "subuid, subgid allowing <$(whoami)> already done!"
    fi

    if [[ ! -d "$HOME/LXD/SHARED" ]]; then
        echo -n "$HOME/LXD/SHARED creating ... "
        mkdir "$HOME/LXD/SHARED" -p
        PREFIX="" echoinfo DONE
    else
        echo "folder <$HOME/LXD/SHARED> already created!"
    fi

    if [[ ! -d "$HOME/LXD/BACKUP" ]]; then
        echo -n "$HOME/LXD/BACKUP creating ... "
        mkdir "$HOME/LXD/BACKUP" -p
        PREFIX="" echoinfo DONE
    else
        echo "folder <$HOME/LXD/BACKUP> already created!"
    fi

}

function set_alias {
    local name="$1"
    local command="$2"
    if ! lxc alias list -f csv | grep -q "^$name,"; then
        echo -n "defining new lxc alias <$name> ..."
        lxc alias add "$name" "$command"
        PREFIX="" echoinfo DONE
    else
        echo "lxc alias <$name> already defined!"
    fi

}

function miaou_evalfrombashrc() {
    local PREFIX="miaou:bashrc"
    output=$(
        /opt/miaou-bash/tools/append_or_replace \
            "^eval \"\\$\($MIAOU_BASEDIR/lib/install.sh shellenv\)\"$" \
            "eval \"\$($MIAOU_BASEDIR/lib/install.sh shellenv)\"" \
            "$HOME/.bashrc"
    )

    if [[ "$output" == "appended" ]]; then
        echo "new path <$MIAOU_BASEDIR> created!"
        SESSION_RELOAD_REQUIRED=true
    else
        echo "path <$MIAOU_BASEDIR> already loaded!"
    fi
}

function ask_target() {
    PS3='Choose miaou target purpose: '
    foods=("Dev" "Beta" "Prod")
    select ans in "${foods[@]}"; do
        builtin echo "${ans^^}"
        break
    done
}

function check_credential {
    local PREFIX="check:credential"

    check_yaml_defined_value /etc/miaou/defaults.yaml 'credential.username' &&
        check_yaml_defined_value /etc/miaou/defaults.yaml 'credential.shadow' &&
        check_yaml_defined_value /etc/miaou/defaults.yaml 'credential.email'
}

function check_target() {
    case "${TARGET^^}" in
    DEV) ;;
    BETA) ;;
    PROD) ;;
    *)
        if [[ -f /etc/miaou/defaults.yaml ]]; then
            # load already defined target in expanded conf
            TARGET=$(grep -Es "^target:" /etc/miaou/defaults.yaml | cut -d ' ' -f2)
        else
            TARGET=$(ask_target)
        fi
        ;;
    esac
    TARGET=${TARGET,,} # downcase
    return 0
}

function miaou_configfiles() {
    local PREFIX="miaou:config"

    if [[ ! -d /etc/miaou ]]; then
        echo -n "configuration initializing ..."
        sudo mkdir -p /etc/miaou
        sudo chown "$USER" /etc/miaou
        PREFIX="" echoinfo DONE
    fi

    if [[ ! -f /etc/miaou/defaults.yaml ]]; then
        echo -n "building /etc/miaou/defaults.yaml for the first time..."
        shadow_passwd=$(sudo grep "$CURRENT_USER" /etc/shadow | cut -d ':' -f2)
        env current_user="$CURRENT_USER" shadow_passwd="$shadow_passwd" valid_email="$valid_email" tera -e --env-key env --env-only -t "$MIAOU_BASEDIR/templates/etc/defaults.yaml.j2" -o /etc/miaou/defaults.yaml >/dev/null
        yq ".target=\"$TARGET\"" /etc/miaou/defaults.yaml -i
        PREFIX="" echoinfo DONE
    fi

    if [[ ! -f /etc/miaou/miaou.yaml ]]; then
        echo -n "building /etc/miaou/miaou.yaml for the first time..."
        cp "$MIAOU_BASEDIR/templates/etc/miaou.yaml.j2" /etc/miaou/miaou.yaml
        PREFIX="" echoinfo DONE
    fi

    PREVIOUS_TARGET=""
    echo "expanded configuration stored in <$MIAOU_CONFIGDIR>!"
    [[ -f "$EXPANDED_CONF" ]] && PREVIOUS_TARGET=$(grep -Es "^target:" "$EXPANDED_CONF" | cut -d ' ' -f2)

    if [[ "$PREVIOUS_TARGET" != "$TARGET" ]]; then
        if [[ -z "$PREVIOUS_TARGET" ]]; then
            echo "new target defined <$TARGET>"
        else
            echowarnn "TARGET has changed from <$PREVIOUS_TARGET> to <$TARGET>, do you agree?"
            if askConfirmation N; then
                echowarn "removing previous settings, please restart <miaou> to apply changes"
                rm "$MIAOU_CONFIGDIR" -rf
            else
                echoerr "TARGET not accepted, exit"
                exit 102
            fi
        fi
        yq ".target=\"$TARGET\"" /etc/miaou/defaults.yaml -i
    else
        echo "target <$TARGET> already defined!"
    fi
}

function opt_link() {
    if [[ $MIAOU_BASEDIR != '/opt/miaou-server' ]]; then
        if [[ -L '/opt/miaou-server' && -d '/opt/miaou-server' && $(readlink /opt/miaou-server) == "$MIAOU_BASEDIR" ]]; then
            echo "symbolic link /opt/miaou-server already set up!"
        else
            sudo rm -f /opt/miaou-server
            sudo ln -s "$MIAOU_BASEDIR" /opt/miaou-server
            echo "symbolic link /opt/miaou-server successfully defined!"
        fi
    else
        echo "real path /opt/miaou-server already set up!"
    fi
}

function miaou_resolver() {
    local PREFIX="miaou:resolver"
    bridge=$(ip addr show lxdbr0 | grep "inet\b" | awk '{print $2}' | cut -d/ -f1)
    gateway=$(ip route | grep default | cut -d' ' -f3)

    echo -n "test gateway <$gateway> as DNS resolver..."
    if dig +short "@$gateway" "$FDN_DOMAINNAME" >/dev/null; then
        resolver="$gateway"
        PREFIX="" echoinfo DONE
    else
        PREFIX="" echoinfo "finally replaced by FDN_RESOLVER=<$FDN_RESOLVER>"
        resolver="$FDN_RESOLVER"
    fi

    if command -v nmcli &>/dev/null; then
        if [[ ! -f /etc/NetworkManager/dispatcher.d/50-miaou-resolver ]]; then
            echo -n "use NetworkManager dispatcher to deal with LXD bridge automatically..."
            sudo cp "$MIAOU_BASEDIR/templates/network-manager/50-miaou-resolver" /etc/NetworkManager/dispatcher.d/
            sudo chmod +x /etc/NetworkManager/dispatcher.d/50-miaou-resolver
            ACTIVE_CONNECTION=$(nmcli -g NAME connection show --active | head -n1)
            sudo nmcli connection up "$ACTIVE_CONNECTION" &>/dev/null
            PREFIX="" echoinfo DONE
        else
            echo "miaou-resolver in NetworkManager dispatcher already initialized!"
        fi
    fi

    if sudo systemctl is-enabled systemd-resolved.service --quiet &>/dev/null; then
        echo -n "disabling systemd-resolved..."
        sudo systemctl stop systemd-resolved.service --quiet
        sudo systemctl disable systemd-resolved.service --quiet
        PREFIX="" echoinfo DONE
    fi

    if ! grep -q "nameserver $bridge" /etc/resolv.conf; then
        echo -n "customize resolv.conf from scratch with bridge=<$bridge>, resolver=<$resolver> ..."
        sudo tee /etc/resolv.conf &>/dev/null <<EOF
# generated by miaou            
nameserver $bridge # LXD bridge
nameserver $resolver # resolver
EOF
        PREFIX="" echoinfo DONE
    else
        echo "customize resolv.conf already defined!"
    fi
}

function extra_dev_desktop {
    # FIXME: detect if DEV && DESKTOP_USAGE to install spicy-client and other desktop tools
    :
}

function override_lxd_service {
    local PREFIX="lxd:override"

    if [[ ! -d /etc/systemd/system/lxd.service.d ]]; then
        echo -n "override lxd service..."
        sudo mkdir -p /etc/systemd/system/lxd.service.d
        sudo tee /etc/systemd/system/lxd.service.d/override.conf &>/dev/null <<EOF
[Service]                                                                                                                                                                        
ExecStartPost=systemctl reload nftables.service
Environment=LANGUAGE=en:en_US
EOF
        sudo systemctl daemon-reload
        sudo systemctl restart lxd.service
        PREFIX="" echoinfo "DONE"
    else
        echo "lxd service already overridden!"
    fi
}

function ask_for_email {
    local PREFIX="install:ask_for_email"
    valid_email=$(auto_detect_email)

    while ! is_email_valid "$valid_email"; do
        echo -n "mandatory email: "
        read -rei "$valid_email" valid_email
    done
}

function preload_bookworm_image {
    local PREFIX="preload:bookworm"

    if [[ $(lxc image list debian/12/cloud -f csv | wc -l) -lt 1 ]]; then
        echo -n "downloading images from public remote, please hold on..."
        sg $NEW_GROUP -c 'lxc image copy images:debian/12/cloud local: --copy-aliases --quiet'
        PREFIX="" echoinfo DONE
    else
        echo -n "refreshing images from public remote..."
        sg $NEW_GROUP -c 'lxc image refresh debian/12/cloud --quiet'
        PREFIX="" echoinfo DONE
    fi
}

function is_email_valid {
    [[ "$1" =~ ^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$ ]]
}

function auto_detect_email {
    found_email="${EMAIL:-}"
    [[ -z "$found_email" ]] && [[ -f /etc/miaou/defaults.yaml ]] && found_email=$(yq '.credential.email' /etc/miaou/defaults.yaml)
    [[ "$found_email" == 'null' ]] && found_email=''
    if ! is_email_valid "$found_email"; then
        if [[ -f $HOME/.ssh/authorized_keys ]]; then
            while IFS= read -r line; do
                found_email="$line"
                is_email_valid "$found_email" && break
            done < <(cut -d ' ' -f3 <"$HOME/.ssh/authorized_keys")
        fi
    fi

    builtin echo "$found_email"
}

### MAIN

if [[ "${1:-}" == "SESSION_RELOAD_REQUIRED" ]]; then
    SESSION_RELOAD_REQUIRED=true
    shift
else
    SESSION_RELOAD_REQUIRED=false
fi

if [[ "${1:-}" == "shellenv" ]]; then
    unset PREFIX
    echo "export MIAOU_BASEDIR=$MIAOU_BASEDIR"
    echo "export PATH=\"\$MIAOU_BASEDIR/scripts\":\$PATH"
else

    . "$MIAOU_BASEDIR/lib/init.sh"

    trap 'status=$?; on_exit; exit $status' EXIT
    trap 'trap - HUP; on_exit SIGHUP; kill -HUP $$' HUP
    trap 'trap - INT; on_exit SIGINT; kill -INT $$' INT
    trap 'trap - TERM; on_exit SIGTERM; kill -TERM $$' TERM

    PREFIX="miaou"
    : $PREFIX
    TARGET=${1:-}
    CURRENT_USER=$(id -un)

    check_normal_user
    check_target
    ask_for_email

    sudo_required
    install_miaou_bash
    install_mandatory_commands
    prepare_toolbox
    add_toolbox_sudoers
    prepare_nftables
    prepare_lxd
    override_lxd_service
    configure_lxd
    preload_bookworm_image
    miaou_resolver
    miaou_evalfrombashrc
    miaou_configfiles
    opt_link
    extra_dev_desktop

    if [[ "$SESSION_RELOAD_REQUIRED" == true ]]; then
        echoinfo "successful \`session\` installation"
        echowarn "current session has been reloaded, due to new group <$NEW_GROUP>! Next time you type \`exit\`, this session will emit a kill signal!"
    else
        echoinfo "successful installation"
    fi
fi