refactor: rearrange/resort args (#1376)

* clean up Cargo.toml

* some small cleanup

* refactor: group together similar args in the help generation and code

This groups together related arguments in both the help text and the
code itself.

* update changelog

* clippy

* builder pattern instead

2 files changed, 533 insertions, 375 deletions

diff --git a/src/options/args.rs b/src/options/args.rs
index 2c524da8..30fe88c9 100644
--- a/src/options/args.rs
+++ b/src/options/args.rs
@@ -1,16 +1,9 @@
-use clap::{builder::PossibleValuesParser, *};
-
-const TEMPLATE: &str = "\
-{name} {version}
-{author}
-
-{about}
-
-{usage-heading} {usage}
+//! Argument parsing via clap.
+//!
+//! Note that you probably want to keep this as a single file so the build script doesn't
+//! trip all over itself.
 
-{all-args}";
-
-const USAGE: &str = "btm [OPTIONS]";
+use clap::{builder::PossibleValuesParser, *};
 
 const DEFAULT_WIDGET_TYPE_STR: &str = {
     #[cfg(feature = "battery")]
@@ -87,191 +80,236 @@ pub fn get_matches() -> ArgMatches {
     build_app().get_matches()
 }
 
-pub fn build_app() -> Command {
-    // Temps
-    let kelvin = Arg::new("kelvin")
-        .short('k')
-        .long("kelvin")
-        .action(ArgAction::SetTrue)
-        .help("Sets the temperature type to Kelvin.")
-        .long_help("Sets the temperature type to Kelvin.");
-
-    let fahrenheit = Arg::new("fahrenheit")
-        .short('f')
-        .long("fahrenheit")
-        .action(ArgAction::SetTrue)
-        .help("Sets the temperature type to Fahrenheit.")
-        .long_help("Sets the temperature type to Fahrenheit.");
-
-    let celsius = Arg::new("celsius")
-        .short('c')
-        .long("celsius")
-        .action(ArgAction::SetTrue)
-        .help("Sets the temperature type to Celsius.")
-        .long_help("Sets the temperature type to Celsius. This is the default option.");
-
-    // All flags. These are in alphabetical order
-    let autohide_time = Arg::new("autohide_time")
-        .long("autohide_time")
-        .action(ArgAction::SetTrue)
-        .help("Temporarily shows the time scale in graphs.")
-        .long_help(
-            "Automatically hides the time scale in graphs after being shown for \
-            a brief moment when zoomed in/out. If time is disabled via --hide_time \
-            then this will have no effect.",
-        );
+trait CommandBuilder {
+    fn general_args(self) -> Self;
 
-    let basic = Arg::new("basic")
-        .short('b')
-        .long("basic")
-        .action(ArgAction::SetTrue)
-        .help("Hides graphs and uses a more basic look.")
-        .long_help(
-            "Hides graphs and uses a more basic look. Design is largely inspired by htop's.",
-        );
+    fn style_args(self) -> Self;
 
-    let case_sensitive = Arg::new("case_sensitive")
-        .short('S')
-        .long("case_sensitive")
-        .action(ArgAction::SetTrue)
-        .help("Enables case sensitivity by default.")
-        .long_help("When searching for a process, enables case sensitivity by default.");
-
-    let current_usage = Arg::new("current_usage")
-        .short('u')
-        .long("current_usage")
-        .action(ArgAction::SetTrue)
-        .help("Sets process CPU% to be based on current CPU%.")
-        .long_help("Sets process CPU% usage to be based on the current system CPU% usage rather than total CPU usage.");
-
-    let unnormalized_cpu = Arg::new("unnormalized_cpu")
-        .short('n')
-        .long("unnormalized_cpu")
-        .action(ArgAction::SetTrue)
-        .help("Show process CPU% usage without normalizing over the number of cores.")
-        .long_help(
-            "Shows all process CPU% usage without averaging over the number of CPU cores in the system.",
-        );
+    fn temperature_args(self) -> Self;
 
-    let disable_click = Arg::new("disable_click")
-        .long("disable_click")
-        .action(ArgAction::SetTrue)
-        .help("Disables mouse clicks.")
-        .long_help("Disables mouse clicks from interacting with the program.");
-
-    let dot_marker = Arg::new("dot_marker")
-        .short('m')
-        .long("dot_marker")
-        .action(ArgAction::SetTrue)
-        .help("Uses a dot marker for graphs.")
-        .long_help("Uses a dot marker for graphs as opposed to the default braille marker.");
-
-    let group_processes = Arg::new("group_processes")
-        .short('g')
-        .long("group_processes")
-        .action(ArgAction::SetTrue)
-        .help("Groups processes with the same name by default.")
-        .long_help("Groups processes with the same name by default.");
-
-    let hide_avg_cpu = Arg::new("hide_avg_cpu")
-        .short('a')
-        .long("hide_avg_cpu")
-        .action(ArgAction::SetTrue)
-        .help("Hides the average CPU usage.")
-        .long_help("Hides the average CPU usage from being shown.");
-
-    let hide_table_gap = Arg::new("hide_table_gap")
-        .long("hide_table_gap")
-        .action(ArgAction::SetTrue)
-        .help("Hides spacing between table headers and entries.")
-        .long_help("Hides the spacing between table headers and entries.");
-
-    let hide_time = Arg::new("hide_time")
-        .long("hide_time")
-        .action(ArgAction::SetTrue)
-        .help("Hides the time scale.")
-        .long_help("Completely hides the time scale from being shown.");
-
-    let process_command = Arg::new("process_command")
-        .long("process_command")
-        .action(ArgAction::SetTrue)
-        .help("Show processes as their commands by default.")
-        .long_help("Show processes as their commands by default in the process widget.");
-
-    let left_legend = Arg::new("left_legend")
-        .short('l')
-        .long("left_legend")
-        .action(ArgAction::SetTrue)
-        .help("Puts the CPU chart legend to the left side.")
-        .long_help("Puts the CPU chart legend to the left side rather than the right side.");
-
-    let regex = Arg::new("regex")
-        .short('R')
-        .long("regex")
-        .action(ArgAction::SetTrue)
-        .help("Enables regex by default.")
-        .long_help("When searching for a process, enables regex by default.");
-
-    let disable_advanced_kill = Arg::new("disable_advanced_kill")
-        .long("disable_advanced_kill")
-        .action(ArgAction::SetTrue)
-        .help("Hides advanced process killing.")
-        .long_help("Hides advanced options to stop a process on Unix-like systems. The only option shown is 15 (TERM).");
-
-    let show_table_scroll_position = Arg::new("show_table_scroll_position")
-        .long("show_table_scroll_position")
-        .action(ArgAction::SetTrue)
-        .help("Shows the scroll position tracker in table widgets.")
-        .long_help("Shows the list scroll position tracker in the widget title for table widgets.");
-
-    let use_old_network_legend = Arg::new("use_old_network_legend")
-        .long("use_old_network_legend")
-        .action(ArgAction::SetTrue)
-        .help("DEPRECATED - uses a separate network legend.")
-        .long_help(
-            "DEPRECATED - uses an older (pre-0.4), separate network widget legend. This display is not \
-            tested anymore and could be broken.",
-        );
+    fn process_args(self) -> Self;
 
-    let whole_word = Arg::new("whole_word")
-        .short('W')
-        .long("whole_word")
-        .action(ArgAction::SetTrue)
-        .help("Enables whole-word matching by default.")
-        .long_help(
-            "When searching for a process, return results that match the entire query by default.",
-        );
+    fn cpu_args(self) -> Self;
+
+    fn mem_args(self) -> Self;
+
+    fn network_args(self) -> Self;
+
+    fn battery_args(self) -> Self;
+
+    fn gpu_args(self) -> Self;
+
+    fn other(self) -> Self;
+}
+
+impl CommandBuilder for Command {
+    fn general_args(self) -> Command {
+        const HEADING: &str = "General Options";
+
+        let autohide_time = Arg::new("autohide_time")
+            .long("autohide_time")
+            .action(ArgAction::SetTrue)
+            .help("Temporarily shows the time scale in graphs.")
+            .long_help(
+                "Automatically hides the time scale in graphs after being shown for \
+            a brief moment when zoomed in/out. If time is disabled via --hide_time \
+            then this will have no effect.",
+            )
+            .help_heading(HEADING);
+
+        let basic = Arg::new("basic")
+            .short('b')
+            .long("basic")
+            .action(ArgAction::SetTrue)
+            .help("Hides graphs and uses a more basic look.")
+            .long_help(
+                "Hides graphs and uses a more basic look. Design is largely inspired by htop's.",
+            )
+            .help_heading(HEADING);
+
+        let disable_click = Arg::new("disable_click")
+            .long("disable_click")
+            .action(ArgAction::SetTrue)
+            .help("Disables mouse clicks.")
+            .long_help("Disables mouse clicks from interacting with the program.")
+            .help_heading(HEADING);
+
+        let dot_marker = Arg::new("dot_marker")
+            .short('m')
+            .long("dot_marker")
+            .action(ArgAction::SetTrue)
+            .help("Uses a dot marker for graphs.")
+            .long_help("Uses a dot marker for graphs as opposed to the default braille marker.")
+            .help_heading(HEADING);
+
+        let hide_table_gap = Arg::new("hide_table_gap")
+            .long("hide_table_gap")
+            .action(ArgAction::SetTrue)
+            .help("Hides spacing between table headers and entries.")
+            .long_help("Hides the spacing between table headers and entries.")
+            .help_heading(HEADING);
+
+        let hide_time = Arg::new("hide_time")
+            .long("hide_time")
+            .action(ArgAction::SetTrue)
+            .help("Hides the time scale.")
+            .long_help("Completely hides the time scale from being shown.")
+            .help_heading(HEADING);
+
+        let left_legend = Arg::new("left_legend")
+            .short('l')
+            .long("left_legend")
+            .action(ArgAction::SetTrue)
+            .help("Puts the CPU chart legend to the left side.")
+            .long_help("Puts the CPU chart legend to the left side rather than the right side.")
+            .help_heading(HEADING);
+
+        let show_table_scroll_position = Arg::new("show_table_scroll_position")
+            .long("show_table_scroll_position")
+            .action(ArgAction::SetTrue)
+            .help("Shows the scroll position tracker in table widgets.")
+            .long_help(
+                "Shows the list scroll position tracker in the widget title for table widgets.",
+            )
+            .help_heading(HEADING);
+
+        let config_location = Arg::new("config_location")
+            .short('C')
+            .long("config")
+            .action(ArgAction::Set)
+            .value_name("CONFIG PATH")
+            .help("Sets the location of the config file.")
+            .long_help(
+                "Sets the location of the config file. Expects a config file in the TOML format. \
+                If it doesn't exist, one is created.",
+            )
+            .value_hint(ValueHint::AnyPath)
+            .help_heading(HEADING);
+
+        let default_time_value = Arg::new("default_time_value")
+            .short('t')
+            .long("default_time_value")
+            .action(ArgAction::Set)
+            .value_name("TIME")
+            .help("Default time value for graphs.")
+            .long_help(
+                "Default time value for graphs. Takes a number in milliseconds or a human duration (e.g. 60s). The minimum time is 30s, and the default is 60s.",
+            )
+            .help_heading(HEADING);
+
+        // TODO: Charts are broken in the manpage
+        let default_widget_count = Arg::new("default_widget_count")
+            .long("default_widget_count")
+            .action(ArgAction::Set)
+            .requires_all(["default_widget_type"])
+            .value_name("INT")
+            .help("Sets the n'th selected widget type as the default.")
+            .long_help(
+                "\
+Sets the n'th selected widget type to use as the default widget.
+Requires 'default_widget_type' to also be set, and defaults to 1.
+
+This reads from left to right, top to bottom. For example, suppose
+we have a layout that looks like:
++-------------------+-----------------------+
+|      CPU (1)      |        CPU (2)        |
++---------+---------+-------------+---------+
+| Process | CPU (3) | Temperature | CPU (4) |
++---------+---------+-------------+---------+
 
-    // All options. Again, alphabetical order.
-    let config_location = Arg::new("config_location")
-        .short('C')
-        .long("config")
-        .action(ArgAction::Set)
-        .value_name("CONFIG PATH")
-        .help("Sets the location of the config file.")
-        .long_help(
-            "Sets the location of the config file. Expects a config file in the TOML format. \
-            If it doesn't exist, one is created.",
-        )
-        .value_hint(ValueHint::AnyPath);
-
-    // TODO: File an issue with manpage, it cannot render charts correctly.
-    let color = Arg::new("color")
-        .long("color")
-        .action(ArgAction::Set)
-        .value_name("COLOR SCHEME")
-        .value_parser(PossibleValuesParser::new([
-            "default",
-            "default-light",
-            "gruvbox",
-            "gruvbox-light",
-            "nord",
-            "nord-light",
-        ]))
-        .hide_possible_values(true)
-        .help("Use a color scheme, use --help for info.")
-        .long_help(
-            "\
+And we set our default widget type to 'CPU'. If we set
+'--default_widget_count 1', then it would use the CPU (1) as
+the default widget. If we set '--default_widget_count 3', it would
+use CPU (3) as the default instead.
+    ",
+            )
+            .help_heading(HEADING);
+
+        let default_widget_type = Arg::new("default_widget_type")
+            .long("default_widget_type")
+            .action(ArgAction::Set)
+            .value_name("WIDGET TYPE")
+            .help("Sets the default widget type, use --help for info.")
+            .long_help(DEFAULT_WIDGET_TYPE_STR)
+            .help_heading(HEADING);
+
+        let expanded_on_startup = Arg::new("expanded_on_startup")
+            .short('e')
+            .long("expanded")
+            .action(ArgAction::SetTrue)
+            .help("Expand the default widget upon starting the app.")
+            .long_help("Expand the default widget upon starting the app. Same as pressing \"e\" inside the app. Use with \"default_widget_type\" and \"default_widget_count\" to select desired expanded widget. This flag has no effect in basic mode (--basic)")
+            .help_heading(HEADING);
+
+        let rate = Arg::new("rate")
+            .short('r')
+            .long("rate")
+            .action(ArgAction::Set)
+            .value_name("TIME")
+            .help("Sets the data refresh rate.")
+            .long_help("Sets the data refresh rate. Takes a number in milliseconds or a human duration (e.g. 5s). The minimum is 250ms, and defaults to 1000ms. Smaller values may take more computer resources.")
+            .help_heading(HEADING);
+
+        let time_delta = Arg::new("time_delta")
+            .short('d')
+            .long("time_delta")
+            .action(ArgAction::Set)
+            .value_name("TIME")
+            .help("The amount of time changed upon zooming.")
+            .long_help("The amount of time changed when zooming in/out. Takes a number in milliseconds or a human duration (e.g. 30s). The minimum is 1s, and defaults to 15s.")
+            .help_heading(HEADING);
+
+        let retention = Arg::new("retention")
+            .long("retention")
+            .action(ArgAction::Set)
+            .value_name("TIME")
+            .help("The timespan of data stored.")
+            .long_help("How much data is stored at once in terms of time. Takes a number in milliseconds or a human duration (e.g. 20m), with a minimum of 1 minute. Note higher values will take up more memory. Defaults to 10 minutes.")
+            .help_heading(HEADING);
+
+        let mut args = [
+            autohide_time,
+            basic,
+            disable_click,
+            dot_marker,
+            hide_table_gap,
+            hide_time,
+            left_legend,
+            show_table_scroll_position,
+            config_location,
+            default_time_value,
+            default_widget_count,
+            default_widget_type,
+            expanded_on_startup,
+            rate,
+            time_delta,
+            retention,
+        ];
+        args.sort_unstable();
+
+        self.args(args)
+    }
+
+    fn style_args(self) -> Command {
+        const HEADING: &str = "Style Options";
+
+        // TODO: File an issue with manpage, it cannot render charts correctly.
+        let color = Arg::new("color")
+            .long("color")
+            .action(ArgAction::Set)
+            .value_name("COLOR SCHEME")
+            .value_parser(PossibleValuesParser::new([
+                "default",
+                "default-light",
+                "gruvbox",
+                "gruvbox-light",
+                "nord",
+                "nord-light",
+            ]))
+            .hide_possible_values(true)
+            .help("Use a color scheme, use --help for info.")
+            .long_help(
+                "\
 Use a pre-defined color scheme. Currently supported values are:
 +------------------------------------------------------------+
 | default                                                    |
@@ -287,214 +325,315 @@ Use a pre-defined color scheme. Currently supported values are:
 | nord-light (nord but for use with light backgrounds)       |
 +------------------------------------------------------------+
 Defaults to \"default\".
-",
-        );
+    ",
+            )
+            .help_heading(HEADING);
 
-    let mem_as_value = Arg::new("mem_as_value")
-        .long("mem_as_value")
-        .action(ArgAction::SetTrue)
-        .help("Defaults to showing process memory usage by value.")
-        .long_help("Defaults to showing process memory usage by value. Otherwise, it defaults to showing it by percentage.");
-
-    let default_time_value = Arg::new("default_time_value")
-        .short('t')
-        .long("default_time_value")
-        .action(ArgAction::Set)
-        .value_name("TIME")
-        .help("Default time value for graphs.")
-        .long_help(
-            "Default time value for graphs. Takes a number in milliseconds or a human duration (e.g. 60s). The minimum time is 30s, and the default is 60s.",
-        );
+        self.arg(color)
+    }
 
-    // TODO: Charts are broken in the manpage
-    let default_widget_count = Arg::new("default_widget_count")
-        .long("default_widget_count")
-        .action(ArgAction::Set)
-        .requires_all(["default_widget_type"])
-        .value_name("INT")
-        .help("Sets the n'th selected widget type as the default.")
-        .long_help(
-            "\
-Sets the n'th selected widget type to use as the default widget.
-Requires 'default_widget_type' to also be set, and defaults to 1.
+    fn temperature_args(self) -> Command {
+        const HEADING: &str = "Temperature Options";
+
+        let celsius = Arg::new("celsius")
+            .short('c')
+            .long("celsius")
+            .action(ArgAction::SetTrue)
+            .help("Use Celsius as the temperature unit.")
+            .long_help("Use Celsius as the temperature unit. This is the default option.")
+            .help_heading(HEADING);
+
+        let fahrenheit = Arg::new("fahrenheit")
+            .short('f')
+            .long("fahrenheit")
+            .action(ArgAction::SetTrue)
+            .help("Use Fahrenheit as the temperature unit.")
+            .help_heading(HEADING);
+
+        let kelvin = Arg::new("kelvin")
+            .short('k')
+            .long("kelvin")
+            .action(ArgAction::SetTrue)
+            .help("Use Kelvin as the temperature unit.")
+            .help_heading(HEADING);
+
+        let temperature_group = ArgGroup::new("TEMPERATURE_TYPE").args([
+            celsius.get_id(),
+            fahrenheit.get_id(),
+            kelvin.get_id(),
+        ]);
+
+        let args = [celsius, fahrenheit, kelvin];
+
+        self.args(args).group(temperature_group)
+    }
 
-This reads from left to right, top to bottom. For example, suppose
-we have a layout that looks like:
-+-------------------+-----------------------+
-|      CPU (1)      |        CPU (2)        |
-+---------+---------+-------------+---------+
-| Process | CPU (3) | Temperature | CPU (4) |
-+---------+---------+-------------+---------+
+    fn process_args(self) -> Command {
+        const HEADING: &str = "Process Options";
+
+        let case_sensitive = Arg::new("case_sensitive")
+            .short('S')
+            .long("case_sensitive")
+            .action(ArgAction::SetTrue)
+            .help("Enables case sensitivity by default.")
+            .long_help("When searching for a process, enables case sensitivity by default.")
+            .help_heading(HEADING);
+
+        let current_usage = Arg::new("current_usage")
+            .short('u')
+            .long("current_usage")
+            .action(ArgAction::SetTrue)
+            .help("Sets process CPU% to be based on current CPU%.")
+            .long_help("Sets process CPU% usage to be based on the current system CPU% usage rather than total CPU usage.")
+            .help_heading(HEADING);
+
+        let unnormalized_cpu = Arg::new("unnormalized_cpu")
+            .short('n')
+            .long("unnormalized_cpu")
+            .action(ArgAction::SetTrue)
+            .help("Show process CPU% usage without normalizing over the number of cores.")
+            .long_help(
+                "Shows all process CPU% usage without averaging over the number of CPU cores in the system.",
+            )
+            .help_heading(HEADING);
+
+        let group_processes = Arg::new("group_processes")
+            .short('g')
+            .long("group_processes")
+            .action(ArgAction::SetTrue)
+            .help("Groups processes with the same name by default.")
+            .long_help("Groups processes with the same name by default.")
+            .help_heading(HEADING);
+
+        let process_command = Arg::new("process_command")
+            .long("process_command")
+            .action(ArgAction::SetTrue)
+            .help("Show processes as their commands by default.")
+            .long_help("Show processes as their commands by default in the process widget.")
+            .help_heading(HEADING);
+
+        let regex = Arg::new("regex")
+            .short('R')
+            .long("regex")
+            .action(ArgAction::SetTrue)
+            .help("Enables regex by default.")
+            .long_help("When searching for a process, enables regex by default.")
+            .help_heading(HEADING);
+
+        let disable_advanced_kill = Arg::new("disable_advanced_kill")
+            .long("disable_advanced_kill")
+            .action(ArgAction::SetTrue)
+            .help("Hides advanced process killing.")
+            .long_help("Hides advanced options to stop a process on Unix-like systems. The only option shown is 15 (TERM).")
+            .help_heading(HEADING);
+
+        let whole_word = Arg::new("whole_word")
+            .short('W')
+            .long("whole_word")
+            .action(ArgAction::SetTrue)
+            .help("Enables whole-word matching by default.")
+            .long_help(
+                "When searching for a process, return results that match the entire query by default.",
+            )
+            .help_heading(HEADING);
+
+        let tree = Arg::new("tree")
+            .short('T')
+            .long("tree")
+            .action(ArgAction::SetTrue)
+            .help("Defaults the process widget be in tree mode.")
+            .long_help("Defaults to showing the process widget in tree mode.")
+            .help_heading(HEADING);
+
+        let mut args = [
+            case_sensitive,
+            current_usage,
+            unnormalized_cpu,
+            group_processes,
+            process_command,
+            regex,
+            whole_word,
+            disable_advanced_kill,
+            tree,
+        ];
+        args.sort_unstable();
+
+        self.args(args)
+    }
 
-And we set our default widget type to 'CPU'. If we set
-'--default_widget_count 1', then it would use the CPU (1) as
-the default widget. If we set '--default_widget_count 3', it would
-use CPU (3) as the default instead.
-",
-        );
+    fn cpu_args(self) -> Command {
+        const HEADING: &str = "CPU Options";
 
-    let default_widget_type = Arg::new("default_widget_type")
-        .long("default_widget_type")
-        .action(ArgAction::Set)
-        .value_name("WIDGET TYPE")
-        .help("Sets the default widget type, use --help for info.")
-        .long_help(DEFAULT_WIDGET_TYPE_STR);
-
-    let expanded_on_startup = Arg::new("expanded_on_startup")
-        .short('e')
-        .long("expanded")
-        .action(ArgAction::SetTrue)
-        .help("Expand the default widget upon starting the app.")
-        .long_help("Expand the default widget upon starting the app. Same as pressing \"e\" inside the app. Use with \"default_widget_type\" and \"default_widget_count\" to select desired expanded widget. This flag has no effect in basic mode (--basic)");
-
-    let rate = Arg::new("rate")
-        .short('r')
-        .long("rate")
-        .action(ArgAction::Set)
-        .value_name("TIME")
-        .help("Sets the data refresh rate.")
-        .long_help("Sets the data refresh rate. Takes a number in milliseconds or a human duration (e.g. 5s). The minimum is 250ms, and defaults to 1000ms. Smaller values may take more computer resources.");
-
-    let time_delta = Arg::new("time_delta")
-        .short('d')
-        .long("time_delta")
-        .action(ArgAction::Set)
-        .value_name("TIME")
-        .help("The amount of time changed upon zooming.")
-        .long_help("The amount of time changed when zooming in/out. Takes a number in milliseconds or a human duration (e.g. 30s). The minimum is 1s, and defaults to 15s.");
-
-    let tree = Arg::new("tree")
-        .short('T')
-        .long("tree")
-        .action(ArgAction::SetTrue)
-        .help("Defaults the process widget be in tree mode.")
-        .long_help("Defaults to showing the process widget in tree mode.");
-
-    let network_use_bytes = Arg::new("network_use_bytes")
-        .long("network_use_bytes")
-        .action(ArgAction::SetTrue)
-        .help("Displays the network widget using bytes.")
-        .long_help("Displays the network widget using bytes. Defaults to bits.");
-
-    let network_use_log = Arg::new("network_use_log")
-        .long("network_use_log")
-        .action(ArgAction::SetTrue)
-        .help("Displays the network widget with a log scale.")
-        .long_help("Displays the network widget with a log scale. Defaults to a non-log scale.");
-
-    let network_use_binary_prefix = Arg::new("network_use_binary_prefix")
-        .long("network_use_binary_prefix")
-        .action(ArgAction::SetTrue)
-        .help("Displays the network widget with binary prefixes.")
-        .long_help(
-            "Displays the network widget with binary prefixes (i.e. kibibits, mebibits) rather than a decimal prefix (i.e. kilobits, megabits). Defaults to decimal prefixes.",
-        );
+        let hide_avg_cpu = Arg::new("hide_avg_cpu")
+            .short('a')
+            .long("hide_avg_cpu")
+            .action(ArgAction::SetTrue)
+            .help("Hides the average CPU usage.")
+            .long_help("Hides the average CPU usage from being shown.")
+            .help_heading(HEADING);
 
-    let retention = Arg::new("retention")
-        .long("retention")
-        .action(ArgAction::Set)
-        .value_name("TIME")
-        .help("The timespan of data stored.")
-        .long_help("How much data is stored at once in terms of time. Takes a number in milliseconds or a human duration (e.g. 20m), with a minimum of 1 minute. Note higher values will take up more memory. Defaults to 10 minutes.");
+        self.arg(hide_avg_cpu)
+    }
 
-    let version = Arg::new("version")
-        .short('V')
-        .long("version")
-        .action(ArgAction::Version)
-        .help("Prints version information.");
+    fn mem_args(self) -> Command {
+        const HEADING: &str = "Memory Options";
 
-    const VERSION: &str = match option_env!("NIGHTLY_VERSION") {
-        Some(nightly_version) => nightly_version,
-        None => crate_version!(),
-    };
+        let mem_as_value = Arg::new("mem_as_value")
+            .long("mem_as_value")
+            .action(ArgAction::SetTrue)
+            .help("Defaults to showing process memory usage by value.")
+            .long_help("Defaults to showing process memory usage by value. Otherwise, it defaults to showing it by percentage.")
+            .help_heading(HEADING);
 
-    let temperature_group = ArgGroup::new("TEMPERATURE_TYPE").args([
-        kelvin.get_id(),
-        fahrenheit.get_id(),
-        celsius.get_id(),
-    ]);
-
-    let mut args = [
-        version,
-        kelvin,
-        fahrenheit,
-        celsius,
-        autohide_time,
-        basic,
-        case_sensitive,
-        process_command,
-        config_location,
-        color,
-        mem_as_value,
-        default_time_value,
-        default_widget_count,
-        default_widget_type,
-        disable_click,
-        dot_marker,
-        group_processes,
-        hide_avg_cpu,
-        hide_table_gap,
-        hide_time,
-        show_table_scroll_position,
-        left_legend,
-        disable_advanced_kill,
-        rate,
-        regex,
-        time_delta,
-        tree,
-        network_use_bytes,
-        network_use_log,
-        network_use_binary_prefix,
-        current_usage,
-        unnormalized_cpu,
-        use_old_network_legend,
-        whole_word,
-        retention,
-        expanded_on_startup,
-        #[cfg(feature = "battery")]
+        #[cfg(not(target_os = "windows"))]
         {
-            Arg::new("battery")
-                .long("battery")
+            let enable_cache_memory = Arg::new("enable_cache_memory")
+                .long("enable_cache_memory")
                 .action(ArgAction::SetTrue)
-                .help("Shows the battery widget.")
-                .long_help(
-                    "Shows the battery widget in default or basic mode. No effect on custom layouts.",
-                )
-        },
+                .help("Enable collecting and displaying cache and buffer memory.")
+                .help_heading(HEADING);
+
+            self.args([mem_as_value, enable_cache_memory])
+        }
+        #[cfg(target_os = "windows")]
+        {
+            self.arg(mem_as_value)
+        }
+    }
+
+    fn network_args(self) -> Command {
+        const HEADING: &str = "Network Options";
+
+        let use_old_network_legend = Arg::new("use_old_network_legend")
+            .long("use_old_network_legend")
+            .action(ArgAction::SetTrue)
+            .help("DEPRECATED - uses a separate network legend.")
+            .long_help(
+                "DEPRECATED - uses an older (pre-0.4), separate network widget legend. This display is not \
+                tested anymore and could be broken.",
+            )
+            .help_heading(HEADING);
+
+        let network_use_bytes = Arg::new("network_use_bytes")
+            .long("network_use_bytes")
+            .action(ArgAction::SetTrue)
+            .help("Displays the network widget using bytes.")
+            .long_help("Displays the network widget using bytes. Defaults to bits.")
+            .help_heading(HEADING);
+
+        let network_use_log = Arg::new("network_use_log")
+            .long("network_use_log")
+            .action(ArgAction::SetTrue)
+            .help("Displays the network widget with a log scale.")
+            .long_help("Displays the network widget with a log scale. Defaults to a non-log scale.")
+            .help_heading(HEADING);
+
+        let network_use_binary_prefix = Arg::new("network_use_binary_prefix")
+            .long("network_use_binary_prefix")
+            .action(ArgAction::SetTrue)
+            .help("Displays the network widget with binary prefixes.")
+            .long_help(
+                "Displays the network widget with binary prefixes (i.e. kibibits, mebibits) rather than a decimal prefix (i.e. kilobits, megabits). Defaults to decimal prefixes.",
+            )
+            .help_heading(HEADING);
+
+        let mut args = [
+            use_old_network_legend,
+            network_use_bytes,
+            network_use_log,
+            network_use_binary_prefix,
+        ];
+
+        args.sort_unstable();
+
+        self.args(args)
+    }
+
+    fn battery_args(self) -> Command {
+        #[cfg(feature = "battery")]
+        {
+            let battery = Arg::new("battery")
+            .long("battery")
+            .action(ArgAction::SetTrue)
+            .help("Shows the battery widget.")
+            .long_help(
+                "Shows the battery widget in default or basic mode. No effect on custom layouts.",
+            )
+            .help_heading("Battery Options");
+
+            self.arg(battery)
+        }
+        #[cfg(not(feature = "battery"))]
+        {
+            self
+        }
+    }
+
+    fn gpu_args(self) -> Command {
         #[cfg(feature = "gpu")]
         {
-            Arg::new("enable_gpu")
+            let enable_gpu = Arg::new("enable_gpu")
                 .long("enable_gpu")
                 .action(ArgAction::SetTrue)
                 .help("Enable collecting and displaying GPU usage.")
-        },
-        #[cfg(not(target_os = "windows"))]
+                .help_heading("GPU Options");
+
+            self.arg(enable_gpu)
+        }
+        #[cfg(not(feature = "gpu"))]
         {
-            Arg::new("enable_cache_memory")
-                .long("enable_cache_memory")
-                .action(ArgAction::SetTrue)
-                .help("Enable collecting and displaying cache and buffer memory.")
-        },
-    ];
+            self
+        }
+    }
+
+    fn other(self) -> Command {
+        const HEADING: &str = "Other Options";
+
+        let version = Arg::new("version")
+            .short('V')
+            .long("version")
+            .action(ArgAction::Version)
+            .help("Prints version information.")
+            .help_heading(HEADING);
 
-    // Manually sort the arguments.
-    args.sort_by(|a, b| {
-        let a = a.get_long().unwrap_or(a.get_id().as_str());
-        let b = b.get_long().unwrap_or(b.get_id().as_str());
+        let help = Arg::new("help")
+            .short('h')
+            .long("help")
+            .action(ArgAction::Help)
+            .help("Prints help (see more with '--help').")
+            .help_heading(HEADING);
 
-        a.cmp(b)
-    });
+        self.args([version, help])
+    }
+}
+
+pub fn build_app() -> Command {
+    const TEMPLATE: &str = include_str!("./args.template");
+    const USAGE: &str = "btm [OPTIONS]";
+    const VERSION: &str = match option_env!("NIGHTLY_VERSION") {
+        Some(nightly_version) => nightly_version,
+        None => crate_version!(),
+    };
 
     Command::new(crate_name!())
-        .version(VERSION)
         .author(crate_authors!())
         .about(crate_description!())
+        .disable_help_flag(true)
+        .disable_version_flag(true)
         .color(ColorChoice::Auto)
-        .override_usage(USAGE)
         .help_template(TEMPLATE)
-        .disable_version_flag(true)
-        .args(args)
-        .group(temperature_group)
+        .override_usage(USAGE)
+        .version(VERSION)
+        .general_args()
+        .style_args()
+        .temperature_args()
+        .process_args()
+        .cpu_args()
+        .mem_args()
+        .network_args()
+        .battery_args()
+        .gpu_args()
+        .other()
 }
 
 #[cfg(test)]
@@ -505,4 +644,15 @@ mod test {
     fn verify_cli() {
         build_app().debug_assert();
     }
+
+    #[test]
+    fn help_heading_no_default() {
+        let mut app = build_app();
+        let help_str = app.render_help();
+
+        asse