add preview and configuration saving to prompt theming

profile.d/bash-completion/prompt-completion.sh

@@ -30,10 +30,12 @@ _complete_set_theme()
             COMPREPLY=()
             return 0
             ;;
+        -p|--preview|-S|--save)
+            ;;
     esac
 
     if [[ "$cur" == -* ]]; then
-        COMPREPLY=( $(compgen -W "-h --help -l --list" -- "$cur") )
+        COMPREPLY=( $(compgen -W "-h --help -l --list -p --preview -S --save" -- "$cur") )
         return 0
     fi
 

profile.d/prompt.sh

@@ -169,6 +169,107 @@ load_theme()
 # ------------------------------------------------------------------------------
 
 
+# ------------------------------------------------------------------------------
+# Persist PROMPT_THEME in profile configuration ([prompt] section).
+# Preference order: ~/.profile.conf when present, else PROFILE_CONF.
+_set_theme_save_prompt_theme()
+{
+    local theme_name="$1"
+    [[ -z "$theme_name" ]] && {
+        disp E "Cannot save an empty theme name."
+        return 1
+    }
+
+    local conf_file
+    if [[ -f "$HOME/.profile.conf" ]]; then
+        conf_file="$HOME/.profile.conf"
+    else
+        conf_file="${PROFILE_CONF:-${MYPATH}/profile.conf}"
+    fi
+
+    local conf_dir
+    conf_dir="${conf_file%/*}"
+    [[ -d "$conf_dir" ]] || mkdir -p "$conf_dir" || {
+        disp E "Unable to create configuration directory: $conf_dir"
+        return 1
+    }
+
+    local tmp_file="${conf_file}.tmp.$$"
+    if [[ ! -e "$conf_file" ]]; then
+        {
+            printf "[prompt]\n"
+            printf "PROMPT_THEME=%s\n" "$theme_name"
+        } > "$conf_file" || {
+            disp E "Unable to write configuration file: $conf_file"
+            return 1
+        }
+        return 0
+    fi
+
+    awk -v theme="$theme_name" '
+        BEGIN {
+            in_prompt = 0
+            saw_prompt = 0
+            wrote_key = 0
+        }
+
+        {
+            if ($0 ~ /^\[[^]]+\][[:space:]]*$/) {
+                if (in_prompt && !wrote_key) {
+                    print "PROMPT_THEME=" theme
+                    wrote_key = 1
+                }
+
+                if ($0 == "[prompt]") {
+                    in_prompt = 1
+                    saw_prompt = 1
+                } else {
+                    in_prompt = 0
+                }
+
+                print
+                next
+            }
+
+            if (in_prompt && $0 ~ /^[[:space:]]*PROMPT_THEME[[:space:]]*=/) {
+                if (!wrote_key) {
+                    print "PROMPT_THEME=" theme
+                    wrote_key = 1
+                }
+                next
+            }
+
+            print
+        }
+
+        END {
+            if (in_prompt && !wrote_key) {
+                print "PROMPT_THEME=" theme
+                wrote_key = 1
+            }
+
+            if (!saw_prompt) {
+                print ""
+                print "[prompt]"
+                print "PROMPT_THEME=" theme
+            }
+        }
+    ' "$conf_file" > "$tmp_file" || {
+        rm -f "$tmp_file"
+        disp E "Unable to update configuration file: $conf_file"
+        return 1
+    }
+
+    mv "$tmp_file" "$conf_file" || {
+        rm -f "$tmp_file"
+        disp E "Unable to replace configuration file: $conf_file"
+        return 1
+    }
+}
+# Not exported, it remains private
+# ------------------------------------------------------------------------------
+
+
 # ------------------------------------------------------------------------------
 # Dynamically switch the prompt theme for the current shell session.
 # Calls load_theme to apply the new colour values immediately, then updates
@@ -179,27 +280,86 @@ load_theme()
 set_theme()
 {
     local theme_dir="${PROMPT_THEME_DIR:-${MYPATH}/profile.d/themes}"
+    local preview=0
+    local save=0
+    local list_only=0
+    local theme_name=""
 
-    # -- help mode -----------------------------------------------------------
+    while [[ $# -gt 0 ]]; do
-    if [[ "$1" == "-h" || "$1" == "--help" ]]; then
+        case "$1" in
-        printf "set_theme: Switch the prompt colour theme for the current shell session.\n\n"
+            -h|--help)
-        printf "Usage: set_theme [options] [theme]\n\n"
+                printf "set_theme: Switch the prompt colour theme for the current shell session.\n\n"
-        printf "Options:\n"
+                printf "Usage: set_theme [options] [theme]\n\n"
-        printf "\t-h, --help\tDisplay this help screen\n"
+                printf "Options:\n"
-        printf "\t-l, --list\tList available themes (default when no argument is given)\n\n"
+                printf "\t-h, --help\tDisplay this help screen\n"
-        printf "Arguments:\n"
+                printf "\t-l, --list\tList available themes (default when no argument is given)\n"
-        printf "\ttheme \tBare theme name (e.g. 'dark') or an explicit path to a .theme file.\n"
+                printf "\t-p, --preview\tPreview a theme without applying it\n\n"
-        printf "\t      \tThemes are searched in: %s\n" "$theme_dir"
+                printf "\t-S, --save\tSave theme to configuration ([prompt] PROMPT_THEME)\n\n"
-        printf "\t      \tOverride with PROMPT_THEME_DIR in profile.conf [prompt].\n\n"
+                printf "Arguments:\n"
-        printf "Examples:\n"
+                printf "\ttheme \tBare theme name (e.g. 'dark') or an explicit path to a .theme file.\n"
-        printf "\tset_theme           \t— list available themes\n"
+                printf "\t      \tThemes are searched in: %s\n" "$theme_dir"
-        printf "\tset_theme dark      \t— apply the dark theme\n"
+                printf "\t      \tOverride with PROMPT_THEME_DIR in profile.conf [prompt].\n\n"
-        printf "\tset_theme ~/my.theme\t— apply a theme by path\n"
+                printf "Examples:\n"
-        return 0
+                printf "\tset_theme           \t— list available themes\n"
+                printf "\tset_theme dark      \t— apply the dark theme\n"
+                printf "\tset_theme -p dark   \t— preview the dark theme\n"
+                printf "\tset_theme -S        \t— save current theme in config\n"
+                printf "\tset_theme -S dark   \t— apply and save the dark theme\n"
+                printf "\tset_theme ~/my.theme\t— apply a theme by path\n"
+                return 0
+                ;;
+            -l|--list)
+                list_only=1
+                shift
+                ;;
+            -p|--preview)
+                preview=1
+                shift
+                ;;
+            -S|--save)
+                save=1
+                shift
+                ;;
+            --)
+                shift
+                break
+                ;;
+            -*)
+                disp E "Unknown option: $1, use \"set_theme --help\" to display usage."
+                return 1
+                ;;
+            *)
+                if [[ -n "$theme_name" ]]; then
+                    disp E "Too many arguments. Usage: set_theme [options] [theme]"
+                    return 1
+                fi
+                theme_name="$1"
+                shift
+                ;;
+        esac
+    done
+
+    if [[ $# -gt 0 ]]; then
+        if [[ -n "$theme_name" ]]; then
+            disp E "Too many arguments. Usage: set_theme [options] [theme]"
+            return 1
+        fi
+        theme_name="$1"
+        shift
     fi
 
     # -- list mode -----------------------------------------------------------
-    if [[ $# -eq 0 || "$1" == "-l" || "$1" == "--list" ]]; then
+    if (( list_only )) || [[ -z "$theme_name" && $preview -eq 0 ]]; then
+        if (( save )); then
+            if [[ -n "${PROMPT_THEME:-}" ]]; then
+                _set_theme_save_prompt_theme "$PROMPT_THEME" || return 1
+                disp I "Saved current prompt theme '$PROMPT_THEME' to configuration."
+                return 0
+            fi
+            disp E "No active theme to save. Apply a theme first or pass one with -S."
+            return 1
+        fi
+
         printf "Available themes in %s:\n" "$theme_dir"
         local f name
         for f in "$theme_dir"/*.theme; do
@@ -215,14 +375,69 @@ set_theme()
         return 0
     fi
 
+    if (( preview )) && [[ -z "$theme_name" ]]; then
+        disp E "--preview requires a theme argument."
+        return 1
+    fi
+
+    if (( preview && save )); then
+        disp E "--preview and --save cannot be used together."
+        return 1
+    fi
+
+    # -- preview mode --------------------------------------------------------
+    if (( preview )); then
+        local old_theme="${PROMPT_THEME:-}"
+        local -a old_prompt_color_vars=()
+        local _v
+        for _v in ${!PROMPT_COLOR_@}; do
+            old_prompt_color_vars+=("$_v=${!_v}")
+        done
+
+        set_colors
+        load_theme "$theme_name" || {
+            set_colors
+            if [[ -n "$old_theme" ]]; then
+                load_theme "$old_theme" || true
+                export PROMPT_THEME="$old_theme"
+            fi
+            return 1
+        }
+
+        printf "Preview for theme '%s':\n" "$theme_name"
+        printf "  %b13:37:00%b %b0%b %b•%b %buser%b@%bhost%b %b/path/to/dir%b %bgit:main +1/-0%b\n" \
+            "${PROMPT_COLOR_TIME_FG:-}" "${DEFAULTCOL:-}" \
+            "${PROMPT_COLOR_OK_FG:-}" "${DEFAULTCOL:-}" \
+            "${PROMPT_COLOR_OK_MARK:-}" "${DEFAULTCOL:-}" \
+            "${PROMPT_COLOR_USER_FG:-}" "${DEFAULTCOL:-}" \
+            "${PROMPT_COLOR_ROOT_FG:-}" "${DEFAULTCOL:-}" \
+            "${PROMPT_COLOR_DIR_FG:-}" "${DEFAULTCOL:-}" \
+            "${PROMPT_COLOR_CTX_FG:-}" "${DEFAULTCOL:-}"
+
+        set_colors
+        if [[ -n "$old_theme" ]]; then
+            load_theme "$old_theme" || true
+            export PROMPT_THEME="$old_theme"
+        fi
+        for _v in "${old_prompt_color_vars[@]}"; do
+            export "$_v"
+        done
+        return 0
+    fi
+
     # -- apply mode ----------------------------------------------------------
-    local theme_name="$1"
 
     # Reset colours to defaults before loading the new theme
     set_colors
     load_theme "$theme_name" || return 1
 
     export PROMPT_THEME="$theme_name"
+    if (( save )); then
+        _set_theme_save_prompt_theme "$theme_name" || return 1
+        disp I "Prompt theme set to $theme_name and saved to configuration."
+        return 0
+    fi
+
     disp I "Prompt theme set to $theme_name."
 }
 export -f set_theme