#!/bin/bash

# SPDX-FileCopyrightText: Christian Schendel <doppelhelix@gmail.com>
# SPDX-License-Identifier: 0BSD

set -eo pipefail

## NOTE A patched version of qt6ct is required.
## NOTE The benefits are:
## NOTE KDE color schemes support,KDE QML applications theming support and
## NOTE KDE's icon engine support
## NOTE See https://aur.archlinux.org/pkgbase/qt6ct-kde/

version='@VERSION@'
pkgname='night-theme-switcher'
default_config_file="/usr/share/$pkgname/nts.skel"

user_name=$(getent passwd "$USER")
homedir=$(echo "$user_name" | cut -d: -f6)

# allow user to override from cli thus using multiple files as needed
XDG_CONFIG_HOME="${XDG_CONFIG_HOME:-$homedir/.config}"
user_config_file=${user_config_file:-$XDG_CONFIG_HOME/$pkgname/$pkgname.conf}

### Begin insert of Arch script
# Avoid any encoding problems
export LANG=C

# check if messages are to be printed using color
unset all_off bold blue green red yellow
if [[ -t 2 ]]; then
  # prefer terminal safe colored and bold text when tput is supported
  if tput setaf 0 &>/dev/null; then
    all_off="$(tput sgr0)"
    bold="$(tput bold)"
    blue="${bold}$(tput setaf 4)"
    green="${bold}$(tput setaf 2)"
    red="${bold}$(tput setaf 1)"
    yellow="${bold}$(tput setaf 3)"
  else
    all_off="\e[1;0m"
    bold="\e[1;1m"
    blue="${bold}\e[1;34m"
    green="${bold}\e[1;32m"
    red="${bold}\e[1;31m"
    yellow="${bold}\e[1;33m"
  fi
fi
readonly all_off bold blue green red yellow

### End insert of Arch script

# dependency checks probably not needed but they do not hurt
if [ ! "$QT_QPA_PLATFORMTHEME" == "qt6ct" ]; then
    notify-send \
        'Wrong environment variable' \
        'Please set QT_QPA_PLATFORMTHEME=qt6ct.' \
        -h string:x-canonical-private-synchronous:sys-notify \
        -u critical \
        -i dialog-error
    mesg="environment variable QT_QPA_PLATFORMTHEME=qt6ct is not set."
    echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
    exit 1
fi
if ! command -v breeze-settings6 >/dev/null 2>&1; then
    notify-send \
        'Missing dependency' \
        'Please install breeze.' \
        -h string:x-canonical-private-synchronous:sys-notify \
        -u critical \
        -i dialog-error
    mesg="breeze is required to use this script."
    echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
    exit 1
fi
if ! command -v qt6ct >/dev/null 2>&1; then
    notify-send \
        'Missing dependency' \
        'Please install qt6ct.' \
        -h string:x-canonical-private-synchronous:sys-notify \
        -u critical \
        -i dialog-error
    mesg="qt6ct-kde is required to use this script."
    echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
    exit 1
fi

if ! command -v gsettings >/dev/null 2>&1; then
    notify-send \
        'Missing dependency' \
        'gsettings not found.\nPlease install glib2.' \
        -h string:x-canonical-private-synchronous:sys-notify \
        -u critical \
        -i dialog-error
    mesg="glib2 is required to use this script."
    echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
    exit 1
fi

check_config() {
    if [[ ! -f $default_config_file ]]; then
        local mesg="$default_config_file is missing.  Reinstall this package to continue."
        echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
        exit 1
    fi
    if [[ ! -f "$user_config_file" ]]; then
        echo -e "${bold}------------------------------------------------------------${all_off}"
        echo -e "${bold} No config file found so creating a fresh one in:${all_off}"
        echo -e "${bold}${blue} $XDG_CONFIG_HOME/$pkgname/$pkgname.conf${all_off}"
        echo
        echo -e "${bold} Edit this file before invoking $pkgname again.${all_off}"
        echo -e "${bold}------------------------------------------------------------${all_off}"
        install -Dm644 $default_config_file "$user_config_file"
        exit 0
    else
        # shellcheck source=nts.skel
        . "$user_config_file"

        # parse config file for correctness
        if [[ ! -f "$kcolorscheme_light" ]]; then
            local mesg="Invalid kcolorscheme_light defined in\n ${blue}$user_config_file"
            echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
            exit 1
        fi
        if [[ ! -f "$kcolorscheme_dark" ]]; then
            local mesg="Invalid kcolorscheme_dark defined in ${blue}$user_config_file"
            echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
            exit 1
        fi
        if [[ ! -d "/usr/share/icons/$icon_theme_light" ]]; then
            local mesg="Invalid icon_theme_light defined in\n ${blue}$user_config_file"
            echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
            exit 1
        fi
        if [[ ! -d "/usr/share/icons/$icon_theme_dark" ]]; then
            local mesg="Invalid icon_theme_dark defined in ${blue}$user_config_file"
            echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
            exit 1
        fi
        if [[ ! -d "/usr/share/themes/$gtk_theme_light" ]]; then
            local mesg="Invalid gtk_theme_light defined in\n ${blue}$user_config_file"
            echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
            exit 1
        fi
        if [[ ! -d "/usr/share/themes/$gtk_theme_dark" ]]; then
            local mesg="Invalid gtk_theme_dark defined in ${blue}$user_config_file"
            echo -e "${red}==> ERROR:${all_off}${bold} ${mesg}${all_off}"
            exit 1
        fi
    fi

}
_reset_settings() {
    ## GTK3
    gtk3_settings_file="$XDG_CONFIG_HOME/gtk-3.0/settings.ini"
    gtk4_settings_file="$XDG_CONFIG_HOME/gtk-4.0/settings.ini"
    qt6ct_settings_file="$XDG_CONFIG_HOME/qt6ct/qt6ct.conf"

    gsettings reset org.gnome.desktop.interface color-scheme
    gsettings reset org.gnome.desktop.interface gtk-theme
    gsettings reset org.gnome.desktop.interface icon-theme

    if [[ ! -w "$gtk3_settings_file" ]]; then
        touch "$gtk3_settings_file"
    fi
    if [[ ! -w "$gtk4_settings_file" ]]; then
        touch "$gtk4_settings_file"
    fi
    if [[ ! -w "$qt6ct_settings_file" ]]; then
        touch "$qt6ct_settings_file"
    fi
}

_set_theme() {
    ## GTK
    gsettings set org.gnome.desktop.interface color-scheme "$gtk_color_scheme"
    gsettings set org.gnome.desktop.interface gtk-theme "$gtk_theme"
    gsettings set org.gnome.desktop.interface icon-theme "$icon_theme"

    ## QT
    if [[ -x /usr/lib/plasma-changeicons ]]; then
        /usr/lib/plasma-changeicons "$icon_theme" >/dev/null 2>&1
    fi
    if [[ -w "$HOME/.config/qt5ct/qt5ct.conf" ]]; then
        sed -i "s/icon_theme=.*/icon_theme=$icon_theme/g" \
            "$HOME/.config/qt5ct/qt5ct.conf"
        sed -i "s,custom_palette=.*,custom_palette=$qt_color_scheme_path,g" \
            "$HOME/.config/qt5ct/qt5ct.conf"
    fi
    if [[ -w "$HOME/.config/qt6ct/qt6ct.conf" ]]; then
        sed -i "s/icon_theme=.*/icon_theme=$icon_theme/g" \
            "$HOME/.config/qt6ct/qt6ct.conf"
        sed -i "s/custom_palette=.*/custom_palette=$qt_custom_palette/g" \
            "$HOME/.config/qt6ct/qt6ct.conf"
        sed -i "s,color_scheme_path=.*,color_scheme_path=$qt_color_scheme_path,g" \
            "$HOME/.config/qt6ct/qt6ct.conf"
    fi
}

switch-dark-light() {
    gtk_color_scheme=$(gsettings get org.gnome.desktop.interface color-scheme)

    if [[ ! $gtk_color_scheme == ''\''prefer-dark'\''' ]]; then
        gtk_color_scheme=prefer-dark
        gtk_prefer_dark_theme=1
        gtk_theme=$gtk_theme_dark
        icon_theme=$icon_theme_dark
        qt_custom_palette=true
        qt_color_scheme_path=$kcolorscheme_dark
        _set_theme
    else
        gtk_color_scheme=prefer-light
        gtk_prefer_dark_theme=0
        gtk_theme=$gtk_theme_light
        icon_theme=$icon_theme_light
        qt_custom_palette=true
        qt_color_scheme_path=$kcolorscheme_light
        _set_theme
    fi
}

restore-theme-on-login() {
    find "$HOME/.config//gtk-3.0/" ! -name 'bookmarks' -type f -exec rm -f {} +
    find "$HOME/.config//gtk-4.0/" ! -name 'bookmarks' -type f -exec rm -f {} +
    gtk_color_scheme=$(gsettings get org.gnome.desktop.interface color-scheme)

    if [[ ! $gtk_color_scheme == ''\''prefer-dark'\''' ]]; then
        gtk_color_scheme=prefer-light
        gtk_prefer_dark_theme=0
        gtk_theme=$gtk_theme_light
        icon_theme=$icon_theme_light
        qt_custom_palette=true
        qt_color_scheme_path=$kcolorscheme_light
        _set_theme
    else
        gtk_color_scheme=prefer-dark
        gtk_prefer_dark_theme=1
        gtk_theme=$gtk_theme_dark
        icon_theme=$icon_theme_dark
        qt_custom_palette=true
        qt_color_scheme_path=$kcolorscheme_dark
        _set_theme
    fi
}

preview() {
  echo -e "${bold}$pkgname v$version${all_off}"
  echo
  echo -e "${bold} KColorScheme"
  if [[ -f "$kcolorscheme_light" ]]; then
    echo -en "${bold}  Light:"
    echo -e "$(tput cr)$(tput cuf 10)${blue}$kcolorscheme_light${all_off}${bold}${all_off}"
  fi
  if [[ -f "$kcolorscheme_dark" ]]; then
    echo -en "${bold}  Dark:"
    echo -e "$(tput cr)$(tput cuf 10)${blue}$kcolorscheme_dark${all_off}${bold}${all_off}"
  fi
  echo
  echo -e "${bold} Icon Theme"
  if [[ -d "/usr/share/icons/$icon_theme_light" ]]; then
    echo -en "${bold}  Light:"
    echo -e "$(tput cr)$(tput cuf 10)${blue}/usr/share/icons/$icon_theme_light${all_off}${bold}${all_off}"
  fi
  if [[ -d "/usr/share/icons/$icon_theme_dark" ]]; then
    echo -en "${bold}  Dark:"
    echo -e "$(tput cr)$(tput cuf 10)${blue}/usr/share/icons/$icon_theme_dark${all_off}${bold}${all_off}"
  fi
  echo
  echo -e "${bold} GTK Theme"
  if [[ -d "/usr/share/themes/$gtk_theme_light" ]]; then
    echo -en "${bold}  Light:"
    echo -e "$(tput cr)$(tput cuf 10)${blue}/usr/share/themes/$gtk_theme_light${all_off}${bold}${all_off}"
  fi
  if [[ -d "/usr/share/themes/$gtk_theme_dark" ]]; then
    echo -en "${bold}  Dark:"
    echo -e "$(tput cr)$(tput cuf 10)${blue}/usr/share/themes/$gtk_theme_dark${all_off}${bold}${all_off}"
  fi

}

case "$1" in
  s)
    check_config && switch-dark-light
    ;;
  r)
    check_config && restore-theme-on-login
    ;;
  c)
    check_config && _reset_settings && preview
    ;;
  p)
    check_config && preview
    ;;
  *)
    echo -e "${bold}$pkgname v$version${all_off}"
    echo
    echo -e "${bold} Usage: ${red}$0${all_off}${bold} ${all_off}${blue}[option]${all_off}"
    echo
    echo -e "${bold}  s) swith between dark and light theme${all_off}"
    echo -e "${bold}  r) restore theme (usefull only once after login)${all_off}"
    echo -e "${bold}  c) create sane default GTK/qt6ct settings files${all_off}"
    echo -e "${bold}  p) Preview settings${all_off}"
    ;;
esac

# vim: set ts=4 sw=4 et: