#!/usr/bin/env bash

manage_desktop_display() {
    # Hardware state is detected on demand; HAS_NVIDIA
    # (GDM3 Wayland option) is populated by the battery.
    _ensure_state_detected

    while true; do
        local choice
        choice=$(_menu "Desktop & Display" \
            "Select an option:" $TUI_ALTO $TUI_ANCHO 6 \
            "1" "Desktop Environment" \
            "2" "Display Manager" \
            "3" "Back to main menu")
        [ -z "$choice" ] && break
        clear
        case "$choice" in
        1) desktop_environment_menu ;;
        2) display_manager_menu ;;
        3) break ;;
        esac
    done
}

desktop_environment_menu() {
    while true; do
        local -a env_items=()
        env_items+=("1" "XFCE")
        env_items+=("2" "LXDE")
        env_items+=("3" "GNOME")
        env_items+=("4" "KDE Plasma")
        env_items+=("5" "Back")
        local choice
        choice=$(_menu "Desktop Environment" \
            "Select a desktop environment:" $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
            "${env_items[@]}")
        [ -z "$choice" ] && break
        clear
        case "$choice" in
        1)
            _load_module xfce || continue
            xfce_menu
            ;;
        2)
            _load_module lxde || continue
            lxde_menu
            ;;
        3)
            _load_module gnome || continue
            gnome_menu
            ;;
        4)
            _load_module kde || continue
            kde_menu
            ;;
        5) break ;;
        esac
    done
}

display_manager_menu() {
    while true; do
        local -a dm_items=()
        dm_items+=("1" "LightDM")
        dm_items+=("2" "GDM3")
        dm_items+=("3" "SDDM")
        if [ "$DEBIAN_VERSION" = "12" ] || [ "$DEBIAN_VERSION" = "13" ]; then
            dm_items+=("4" "greetd")
            dm_items+=("5" "Back")
        else
            dm_items+=("4" "Back")
        fi
        local choice
        choice=$(_menu "Display Manager" \
            "Select an option:" $TUI_ALTO $TUI_ANCHO 6 \
            "${dm_items[@]}")
        [ -z "$choice" ] && break
        clear
        case "$choice" in
        1) lightdm_config_menu ;;
        2) configure_gdm3 ;;
        3) configure_sddm ;;
        4)
            if [ "$DEBIAN_VERSION" = "12" ] || [ "$DEBIAN_VERSION" = "13" ]; then
                configure_greetd
            else
                break
            fi
            ;;
        5) break ;;
        esac
    done
}

lightdm_config_menu() {
    local -a items=()
    items+=("install_lightdm" "Install LightDM & GTK Greeter" "$(_state lightdm)")
    items+=("enable_userlist" "Enable user list at login screen" "OFF")
    items+=("enable_autologin" "Enable autologin for current user" "OFF")
    local choices
    choices=$(_checklist "LightDM Configuration" \
        "Select options to apply:" $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
        "${items[@]}")
    if [ -z "$choices" ]; then
        echo "No changes."
        _pause
        return
    fi
    local cleaned
    cleaned=$(echo "$choices" | tr -d '"')
    # SECURITY: Convert to array to avoid word splitting and command injection.
    local -a lm_items=()
    while IFS= read -r _item; do
        [ -n "$_item" ] && lm_items+=("$_item")
    done < <(echo "$cleaned" | tr ' ' '\n')

    for item in "${lm_items[@]}"; do
        case $item in
        install_lightdm)
            if ! is_installed lightdm || ! is_installed lightdm-gtk-greeter-settings; then
                echo "lightdm shared/default-x-display-manager select lightdm" | sudo debconf-set-selections
                _run_cmd "LightDM" "sudo apt install -y lightdm lightdm-gtk-greeter lightdm-gtk-greeter-settings" "Installing LightDM & GTK Greeter..."
            else
                echo -e "${GREEN}[LightDM] LightDM and GTK Greeter settings are already installed, skipping...${NC}"
            fi
            ;;
        enable_userlist)
            local conf="/etc/lightdm/lightdm.conf.d/50-debianito-userlist.conf"
            sudo mkdir -p "$(dirname "$conf")"
            if echo "[Seat:*]
greeter-hide-users=false" | sudo tee "$conf" >/dev/null; then
                echo -e "${GREEN}User list enabled in LightDM.${NC}"
            else
                echo -e "${RED}Failed to write configuration.${NC}"
            fi
            ;;
        enable_autologin)
            local dm_conf="/etc/lightdm/lightdm.conf"
            local lightdm_user="${SUDO_USER:-}"
            if [ -z "$lightdm_user" ] || [ "$lightdm_user" = "root" ]; then
                lightdm_user=$(awk -F: '$3>=1000 && $3<65534 {print $1}' /etc/passwd | head -1)
            fi
            sudo sed -i 's/^#[[:space:]]*autologin-user[[:space:]=].*/autologin-user='"$lightdm_user"'/' "$dm_conf"
            sudo sed -i 's/^#[[:space:]]*autologin-user-timeout[[:space:]=].*/autologin-user-timeout=0/' "$dm_conf"
            echo -e "${GREEN}Autologin enabled for user: ${lightdm_user}${NC}"
            ;;
        esac
    done
    _pause
}

configure_greetd() {
    while true; do
        local -a gd_items=()
        gd_items+=("1" "Install base greetd")
        gd_items+=("2" "Install greetd + tuigreet (Recommended TUI greeter)")
        if [ "$DEBIAN_VERSION" = "13" ]; then
            gd_items+=("3" "Install gtkgreet (Requires manual setup)")
            gd_items+=("4" "Install nwg-hello (Requires manual setup)")
            gd_items+=("5" "Install wlgreet (Requires manual setup)")
            gd_items+=("6" "Back")
        else
            gd_items+=("3" "Back")
        fi
        local choice
        choice=$(_menu "greetd Configuration" \
            "Select an option:" \
            $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
            "${gd_items[@]}")
        [ -z "$choice" ] && return
        clear
        case "$choice" in
        1)
            echo "greetd shared/default-x-display-manager select greetd" | sudo debconf-set-selections
            _run_cmd "greetd" "sudo apt install -y greetd" "Installing greetd..."
            _msg "greetd" "Warning: greetd was installed but NOT configured.\n\nYou must manually create /etc/greetd/config.toml\nto be able to log in.\n\nSee 'man greetd' and 'man 5 greetd-sessions'."
            ;;
        2)
            if [ "$DEBIAN_VERSION" = "12" ]; then
                if [ "$(is_backports_enabled)" != true ]; then
                    _write_deb822_backports "bookworm"
                    _ensure_apt_updated
                fi
                _run_cmd "greetd" "sudo apt install -y -t bookworm-backports tuigreet greetd" "Installing greetd + tuigreet..."
            else
                _run_cmd "greetd" "sudo apt install -y greetd tuigreet" "Installing greetd + tuigreet..."
            fi
            _msg "greetd" "Warning: greetd was installed but NOT configured.\n\nYou must manually create /etc/greetd/config.toml\nto be able to log in.\n\nSee 'man greetd' and 'man 5 greetd-sessions'."
            ;;
        3)
            if [ "$DEBIAN_VERSION" = "13" ]; then
                echo "greetd shared/default-x-display-manager select greetd" | sudo debconf-set-selections
                _run_cmd "greetd" "sudo apt install -y greetd gtkgreet" "Installing greetd + gtkgreet..."
                _msg "greetd" "Warning: greetd was installed but NOT configured.\n\nYou must manually create /etc/greetd/config.toml\nto be able to log in.\n\nSee 'man greetd' and 'man 5 greetd-sessions'."
            else
                return
            fi
            ;;
        4)
            if [ "$DEBIAN_VERSION" = "13" ]; then
                echo "greetd shared/default-x-display-manager select greetd" | sudo debconf-set-selections
                _run_cmd "greetd" "sudo apt install -y greetd nwg-hello" "Installing greetd + nwg-hello..."
                _msg "greetd" "Warning: greetd was installed but NOT configured.\n\nYou must manually create /etc/greetd/config.toml\nto be able to log in.\n\nSee 'man greetd' and 'man 5 greetd-sessions'."
            fi
            ;;
        5)
            if [ "$DEBIAN_VERSION" = "13" ]; then
                echo "greetd shared/default-x-display-manager select greetd" | sudo debconf-set-selections
                _run_cmd "greetd" "sudo apt install -y greetd wlgreet" "Installing greetd + wlgreet..."
                _msg "greetd" "Warning: greetd was installed but NOT configured.\n\nYou must manually create /etc/greetd/config.toml\nto be able to log in.\n\nSee 'man greetd' and 'man 5 greetd-sessions'."
            fi
            ;;
        6) return ;;
        esac
    done
}

configure_gdm3() {
    while true; do
        local items_enabled=()
        items_enabled+=("install" "Install/Reinstall gdm3 (Set as default)" "$(_state gdm3)")
        items_enabled+=("userlist" "Hide user list (disable-user-list)" "OFF")
        items_enabled+=("autologin" "Configure Autologin" "OFF")
        if [ "$DEBIAN_VERSION" = "12" ] || [ "$DEBIAN_VERSION" = "13" ]; then
            if [ "$HAS_NVIDIA" = true ]; then
                items_enabled+=("wayland" "Force Enable Wayland on NVIDIA (Risk!)" "OFF")
            fi
        fi
        local choice
        choice=$(_checklist "GDM3 Configuration" \
            "Select options to apply:" \
            $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
            "${items_enabled[@]}")
        [ -z "$choice" ] && return
        clear

        local cleaned
        cleaned=$(echo "$choice" | tr -d '"')

        # SECURITY: Convert to array to avoid word splitting and command injection.
        local -a gdm_items=()
        while IFS= read -r _item; do
            [ -n "$_item" ] && gdm_items+=("$_item")
        done < <(echo "$cleaned" | tr ' ' '\n')

        for item in "${gdm_items[@]}"; do
            case $item in
            install)
                echo "gdm3 shared/default-x-display-manager select gdm3" | sudo debconf-set-selections
                _run_cmd "GDM3" "sudo apt install -y gdm3" "Installing gdm3..."
                ;;
            userlist)
                local greeter_conf="/etc/gdm3/greeter.dconf-defaults"
                if sudo grep -q '^disable-user-list=true' "$greeter_conf" 2>/dev/null; then
                    sudo sed -i 's/^disable-user-list=true/# disable-user-list=true/' "$greeter_conf"
                    echo -e "${GREEN}User list is now VISIBLE.${NC}"
                else
                    sudo sed -i 's/^#[[:space:]]*disable-user-list=true/disable-user-list=true/' "$greeter_conf"
                    echo -e "${GREEN}User list is now HIDDEN.${NC}"
                fi
                sudo dpkg-reconfigure gdm3 >/dev/null 2>&1
                ;;
            autologin)
                local daemon_conf="/etc/gdm3/daemon.conf"
                local username
                username=$(_inputbox "GDM3 Autologin" \
                    "Enter username to autologin (leave empty to DISABLE autologin):" 10 60)
                if [ -n "$username" ]; then
                    if ! [[ "$username" =~ ^[a-z_][a-z0-9_-]{0,31}$ ]]; then
                        _msg_red "GDM3 Autologin" "Invalid username: ${username}"
                        continue
                    fi
                    [ -f "$daemon_conf" ] || sudo touch "$daemon_conf"
                    sudo sed -i 's/^# *AutomaticLoginEnable[[:space:]=].*/AutomaticLoginEnable=true/' "$daemon_conf"
                    sudo sed -i "s|^# *AutomaticLogin[[:space:]=].*|AutomaticLogin=${username}|" "$daemon_conf"
                    echo -e "${GREEN}Autologin enabled for user: ${username}${NC}"
                else
                    sudo sed -i 's/^AutomaticLoginEnable[[:space:]=].*/# AutomaticLoginEnable=false/' "$daemon_conf"
                    sudo sed -i 's/^AutomaticLogin[[:space:]=].*/# AutomaticLogin=/' "$daemon_conf"
                    echo -e "${GREEN}Autologin disabled.${NC}"
                fi
                ;;
            wayland)
                local rules_link="/etc/udev/rules.d/61-gdm.rules"
                if [ -L "$rules_link" ] || [ -f "$rules_link" ]; then
                    sudo rm -f "$rules_link"
                    echo -e "${GREEN}Reverted. Wayland will be disabled by default on next reboot.${NC}"
                elif [ -f "/lib/udev/rules.d/61-gdm.rules" ]; then
                    if _confirm "Wayland on NVIDIA" \
                        "Force-enable Wayland on NVIDIA?\n\nRisk: This may break graphics or cause instability.\nProceed?"; then
                        sudo ln -s /dev/null "$rules_link"
                        echo -e "${GREEN}Wayland override created. Reboot required.${NC}"
                    fi
                fi
                ;;
            esac
        done
        _pause
    done
}

configure_sddm() {
    while true; do
        local choice
        choice=$(_menu "SDDM Configuration" \
            "Select an option:" \
            $TUI_ALTO $TUI_ANCHO $TUI_ALTO_LISTA \
            "1" "Install SDDM (Set as default)" \
            "2" "Enable Autologin" \
            "3" "Back")
        [ -z "$choice" ] && return
        clear
        case "$choice" in
        1)
            echo "sddm shared/default-x-display-manager select sddm" | sudo debconf-set-selections
            _run_cmd "SDDM" "sudo apt install -y sddm" "Installing SDDM..."
            ;;
        2)
            local sddm_session=""
            local sddm_user="${SUDO_USER:-}"
            if [ -z "$sddm_user" ] || [ "$sddm_user" = "root" ]; then
                sddm_user=$(awk -F: '$3>=1000 && $3<65534 {print $1}' /etc/passwd | head -1)
            fi
            if [ -f /usr/share/wayland-sessions/plasmawayland.desktop ]; then
                sddm_session="plasmawayland"
            elif [ -f /usr/share/wayland-sessions/lxqt-wayland.desktop ]; then
                sddm_session="lxqt-wayland"
            elif [ -f /usr/share/xsessions/plasma.desktop ]; then
                sddm_session="plasma"
            elif [ -f /usr/share/xsessions/lxqt.desktop ]; then
                sddm_session="lxqt"
            fi
            sudo mkdir -p /etc/sddm.conf.d
            cat <<EOF | sudo tee /etc/sddm.conf.d/autologin.conf >/dev/null
[Autologin]
User=${sddm_user}
Session=${sddm_session}
Relogin=false
EOF
            if [ -n "$sddm_session" ]; then
                echo -e "${GREEN}Autologin enabled for user ${sddm_user}, session: ${sddm_session}.${NC}"
            else
                echo -e "${YELLOW}Autologin enabled for user ${sddm_user}. No session set (SDDM will use default).${NC}"
            fi
            _pause
            ;;
        3) return ;;
        esac
    done
}

# ── SP2 shared helpers ────────────────────────────

# Print the display manager already configured as the
# X11 default (/etc/X11/default-display-manager), or an
# enabled DM systemd unit; print nothing when none is
# found. Desktop installers use this to avoid overwriting
# an existing display manager setup.
_existing_display_manager() {
    local dm=""
    local dm_path=""
    # Config path is overridable for tests (same pattern as
    # APT_DIR): the suite must never read the real system file.
    local dm_file="${DM_FILE:-/etc/X11/default-display-manager}"
    if [ -s "$dm_file" ]; then
        dm_path=$(cat "$dm_file" 2>/dev/null) || dm_path=""
        [ -n "$dm_path" ] && dm=$(basename "$dm_path")
    fi
    if [ -z "$dm" ]; then
        local cand
        for cand in gdm3 lightdm sddm greetd gdm; do
            if systemctl is-enabled "$cand" 2>/dev/null | grep -q '^enabled$'; then
                dm="$cand"
                break
            fi
        done
    fi
    printf '%s\n' "$dm"
}

# Offer the standard PipeWire audio stack right after a
# desktop install, when no PipeWire server is present
# yet. _install_pipewire_standard gates itself internally,
# so no pre-prompt is needed here. Declining is a choice,
# not an error: always ends in return 0 so it is safe as
# the last call of an installer.
_offer_pipewire_after_desktop() {
    local pkg_check="pipewire-audio"
    [ "$DEBIAN_VERSION" = "11" ] && pkg_check="pipewire"
    is_installed "$pkg_check" && return 0

    if _confirm "PipeWire Audio" \
        "No PipeWire audio server is installed.\n\nInstall the PipeWire audio stack (recommended)?"; then
        _install_pipewire_standard
    fi
    return 0
}