Add xresources config wrapper

Created a wrapper script to customize theme variables (colors,
fonts, etc) according with your X resources file (~/.Xresources).

As dunst is not a X exclusive notification daemon, this script
could be a workarround to solve this.

Related with: dunst-project#357

contrib/dunst_xr_theme_changer.sh

@@ -0,0 +1,186 @@
+#!/usr/bin/env bash
+###############################################################################
+#
+# This script creates a dunst user configuration file in
+# $XDG_CONFIG_HOME/dunst/ folder, changing dunst basic theming options
+# according to your current X resources color palette.
+#
+# It gets your current user configuration file
+# -$HOME/.conf/dunst/dunstrc, which is copied from the default
+# config file in /usr/share/dunst/dunstrc if it does not exist- and
+# changes the defined attributes -declared further on in the script as
+# $theme_attr_dict dictionary- to the new ones. Then it dumps the new
+# configuration to $user_xr_color_conf file.
+#
+###############################################################################
+
+set -e
+
+# Check if appres is installed
+if [ ! "$(command -v appres)" ]; then
+    printf 'xorg-appres is not installed.'
+    exit 1
+fi
+
+readonly script_name="$(basename "$0")"
+
+# Function to get resource values
+xrdb_get () {
+    output="$(appres Dunst | grep "$1:" | head -n1 | cut -f2)"
+    default="$2"
+    printf '%s' "${output:-$default}"
+}
+
+# Attributes dictionary.
+#
+# Format:
+#     ["<section>-<attribute>"]="<value>|$(xrdb_get '<X_resource>' '<default>')"
+#
+# You have to ensure <attribute> exists in <section> in $user_conf file
+declare -A theme_attr_dict=(
+    ["global-font"]="$(xrdb_get 'font' 'Monospace') $(xrdb_get '*.font_size:' '11')"
+    ["global-frame_width"]="$(xrdb_get 'border_width' '1')"
+    ["global-frame_color"]="\"$(xrdb_get 'color8' '#65737e')\""
+
+    ["urgency_low-background"]="\"$(xrdb_get 'color0' '#2b303b')\""
+    ["urgency_low-foreground"]="\"$(xrdb_get 'color4' '#65737e')\""
+    ["urgency_low-frame_color"]="\"$(xrdb_get 'color4' '#65737e')\""
+
+    ["urgency_normal-background"]="\"$(xrdb_get 'color0' '#2b303b')\""
+    ["urgency_normal-foreground"]="\"$(xrdb_get 'color2' '#a3be8c')\""
+    ["urgency_normal-frame_color"]="\"$(xrdb_get 'color2' '#a3be8c')\""
+
+    ["urgency_critical-background"]="\"$(xrdb_get 'color0' '#2b303b')\""
+    ["urgency_critical-foreground"]="\"$(xrdb_get 'color1' '#bf616a')\""
+    ["urgency_critical-frame_color"]="\"$(xrdb_get 'color1' '#bf616a')\""
+)
+
+# Attributes dictionary keys.
+readonly valid_keys="${!theme_attr_dict[@]}"
+
+
+#
+# File paths
+#
+# User config dir and file
+readonly user_conf_dir="${XDG_CONFIG_HOME:-$HOME/.config}/dunst"
+readonly user_conf="$user_conf_dir/dunstrc"
+
+# Default config dir and example file
+example_conf_dir="/usr/share/dunst"
+example_conf="$example_conf_dir/dunstrc"
+
+# User xresources color config file
+readonly user_xr_color_conf="$user_conf_dir/dunstrc_xr_colors"
+
+
+# Check if the user config directory exists
+if ! [ -d "$user_conf_dir" ]; then
+    printf 'Creating folder "%s".\n' "$user_conf_dir"
+    mkdir -p  "$user_conf_dir"
+fi
+
+# Check if the user config file exists
+if ! [ -f "$user_conf" ]; then
+    printf '"%s" file does not exist.\nChecking for config file example.' \
+               "$user_conf"
+
+    if [ -d "/usr/share/dunst" ]; then
+        # Archlinux default dir and example file
+        example_conf_dir="/usr/share/dunst"
+
+        if [ -f "$example_conf_dir/dunstrc" ]; then
+            example_conf="$example_conf_dir/dunstrc"
+        else
+            printf 'Could not find the example config file in "%s".
+               \nPlease, change $example_conf variable in the script.' \
+                   "$example_conf_dir"
+            exit 1
+        fi
+
+    elif [ -d "/usr/share/doc/dunst" ]; then
+        # Debian/Ubuntu default dir
+        example_conf_dir="/usr/share/doc/dunst"
+
+        if [ -f "$example_conf_dir/dunstrc.example.gz" ]; then
+            # Ubuntu <= 17.10 and Debian <= 1.2.0-2 example file:
+            example_conf="$example_conf_dir/dunstrc.example.gz"
+        elif [ -f "$example_conf_dir/dunstrc.gz" ]; then
+            # Ubuntu >= 18.04 and Debian >= 1.3.0-2 example file:
+            example_conf="$example_conf_dir/dunstrc.gz"
+        else
+            printf 'Could not find the example config file in "%s".
+               \nPlease, change $example_conf variable in the script.' \
+                   "$example_conf_dir"
+            exit 1
+        fi
+
+    else
+        printf 'Could not find the example config directory.
+           \nPlease, change $example_conf_dir variable in the script.'
+        exit 1
+    fi
+
+    printf 'Copying example config to "%s".\n' "$user_conf_dir"
+
+    # Get the extension to check if the file is compressed
+    if [[ "${example_conf##*\.}" == "gz" ]]; then
+        # Extract example file to user config file
+        gunzip -c "$example_conf" > "$user_conf"
+    else
+        cp "$example_conf" "$user_conf_dir"
+    fi
+
+fi
+
+# Regular expressions
+readonly re_section_line='^\[(.*)\]$'
+readonly re_empty_comment_line='(^$)|(^[[:space:]]*(\#)|(;))'
+readonly re_attribute_line='^([[:space:]]*)([_[:alnum:]]+)'
+
+# Create an array with the file lines
+mapfile -t conf < "$user_conf"
+
+# Iterate over the file lines
+for idx in "${!conf[@]}"; do
+    # Current line
+    curr_line="${conf[$idx]}"
+    # If we are in a new section:
+    if [[ "$curr_line" =~ $re_section_line ]]; then
+        curr_section="${BASH_REMATCH[1]}"
+        continue
+    fi
+    # Skip the line if it is empty or has a comment
+    if [[ "$curr_line" =~ $re_empty_comment_line ]]; then
+        continue
+    fi
+    # Get the attribute in the current line
+    [[ "$curr_line" =~ $re_attribute_line ]]
+    curr_attr_name="${BASH_REMATCH[2]}"
+    curr_sett_name="${curr_section}-${curr_attr_name}"
+    # If the current attribute is not in our dictionary, continue
+    case "$valid_keys" in
+        *"$curr_sett_name"*)
+            conf[$idx]="    ${curr_attr_name} = ${theme_attr_dict[$curr_sett_name]}"
+            ;;
+    esac
+done
+
+# Create a header for the xr_color config file
+user_xr_color_conf_content="\
+###################################
+#
+# Config file created with
+# $script_name wrapper
+#
+###################################
+
+"
+
+# After everything is completed, write the new config to a file
+user_xr_color_conf_content+="$(printf '%s\n' "${conf[@]}")"
+
+printf '%s\n' "$user_xr_color_conf_content" > "$user_xr_color_conf"
+
+printf '"%s" updated successfully.\n' "$user_xr_color_conf"
+