Restructure modules

Modules are now separated into a fashion where the library can be used
for most use cases, without needing to compile the rest.

The core of serenity, with no features enabled, contains only the
struct (model) definitions, constants, and prelude. Models do not have
most functions compiled in, as that is separated into the `model`
feature.

The `client` module has been split into 3 modules: `client`, `gateway`,
and `http`.

`http` contains functions to interact with the REST API. `gateway`
contains the Shard to interact with the gateway, requiring `http` for
retrieving the gateway URL. `client` requires both of the other features
and acts as an abstracted interface over both the gateway and REST APIs,
handling the event loop.

The `builder` module has been separated from `utils`, and can now be
optionally compiled in. It and the `http` feature are required by the
`model` feature due to a large number of methods requiring access to
them.

`utils` now contains a number of utilities, such as the Colour struct, the
`MessageBuilder`, and mention parsing functions.

Each of the original `ext` modules are still featured, with `cache` not
requiring any feature to be enabled, `framework` requiring the `client`,
`model`, and `utils`, and `voice` requiring `gateway`.

In total the features and their requirements are:

- `builder`: none
- `cache`: none
- `client`: `gateway`, `http`
- `framework`: `client`, `model`, `utils`
- `gateway`: `http`
- `http`: none
- `model`: `builder`, `http`
- `utils`: none
- `voice`: `gateway`

The default features are `builder`, `cache`, `client`, `framework`,
`gateway`, `model`, `http`, and `utils`.

To help with forwards compatibility, modules have been re-exported from
their original locations.

1 files changed, 285 insertions, 0 deletions

diff --git a/src/framework/help_commands.rs b/src/framework/help_commands.rs
new file mode 100644
index 0000000..1f38bd5
--- /dev/null
+++ b/src/framework/help_commands.rs
@@ -0,0 +1,285 @@
+//! A collection of default help commands for the framework.
+//!
+//! # Example
+//!
+//! Using the [`with_embeds`] function to have the framework's help message use
+//! embeds:
+//!
+//! ```rs,no_run
+//! use serenity::ext::framework::help_commands;
+//! use serenity::Client;
+//! use std::env;
+//!
+//! let mut client = Client::login(&env::var("DISCORD_TOKEN").unwrap());
+//! client.with_framework(|f| f
+//!     .command("help", |c| c.exec_help(help_commands::with_embeds)));
+//! ```
+//!
+//! The same can be accomplished with no embeds by substituting `with_embeds`
+//! with the [`plain`] function.
+//!
+//! [`plain`]: fn.plain.html
+//! [`with_embeds`]: fn.with_embeds.html
+
+use std::collections::HashMap;
+use std::sync::Arc;
+use std::fmt::Write;
+use super::command::InternalCommand;
+use super::{Command, CommandGroup, CommandOrAlias};
+use ::client::Context;
+use ::model::Message;
+use ::utils::Colour;
+
+fn error_embed(ctx: &mut Context, input: &str) {
+    let _ = ctx.channel_id
+        .unwrap()
+        .send_message(|m| m
+        .embed(|e| e
+            .colour(Colour::dark_red())
+            .description(input)));
+}
+
+fn remove_aliases(cmds: &HashMap<String, CommandOrAlias>) -> HashMap<&String, &InternalCommand> {
+    let mut result = HashMap::new();
+
+    for (n, v) in cmds {
+        if let CommandOrAlias::Command(ref cmd) = *v {
+            result.insert(n, cmd);
+        }
+    }
+
+    result
+}
+
+pub fn with_embeds(ctx: &mut Context,
+                   _: &Message,
+                   groups: HashMap<String, Arc<CommandGroup>>,
+                   args: &[String]) -> Result<(), String> {
+    if !args.is_empty() {
+        let name = args.join(" ");
+
+        for (group_name, group) in groups {
+            let mut found: Option<(&String, &InternalCommand)> = None;
+
+            for (command_name, command) in &group.commands {
+                let with_prefix = if let Some(ref prefix) = group.prefix {
+                    format!("{} {}", prefix, command_name)
+                } else {
+                    command_name.to_owned()
+                };
+
+                if name == with_prefix || name == *command_name {
+                    match *command {
+                        CommandOrAlias::Command(ref cmd) => {
+                            found = Some((command_name, cmd));
+                        },
+                        CommandOrAlias::Alias(ref name) => {
+                            error_embed(ctx, &format!("Did you mean \"{}\"?", name));
+                            return Ok(());
+                        }
+                    }
+                }
+            }
+
+            if let Some((command_name, command)) = found {
+                if !command.help_available {
+                    error_embed(ctx, "**Error**: No help available.");
+
+                    return Ok(());
+                }
+
+                let _ = ctx.channel_id.unwrap().send_message(|m| {
+                    m.embed(|e| {
+                        let mut embed = e.colour(Colour::rosewater())
+                            .title(command_name);
+                        if let Some(ref desc) = command.desc {
+                            embed = embed.description(desc);
+                        }
+
+                        if let Some(ref usage) = command.usage {
+                            embed = embed.field(|f| f
+                                .name("Usage")
+                                .value(&format!("`{} {}`", command_name, usage)));
+                        }
+
+                        if let Some(ref example) = command.example {
+                            embed = embed.field(|f| f
+                                .name("Sample usage")
+                                .value(&format!("`{} {}`", command_name, example)));
+                        }
+
+                        if group_name != "Ungrouped" {
+                            embed = embed.field(|f| f
+                                .name("Group")
+                                .value(&group_name));
+                        }
+
+                        let available = if command.dm_only {
+                            "Only in DM"
+                        } else if command.guild_only {
+                            "Only in guilds"
+                        } else {
+                            "In DM and guilds"
+                        };
+
+                        embed = embed.field(|f| f
+                            .name("Available")
+                            .value(available));
+
+                        embed
+                    })
+                });
+
+                return Ok(());
+            }
+        }
+
+        let error_msg = format!("**Error**: Command `{}` not found.", name);
+        error_embed(ctx, &error_msg);
+
+        return Ok(());
+    }
+
+    let _ = ctx.channel_id.unwrap().send_message(|m| m
+        .embed(|mut e| {
+            e = e.colour(Colour::rosewater())
+                .description("To get help with an individual command, pass its \
+                              name as an argument to this command.");
+
+            for (group_name, group) in groups {
+                let mut desc = String::new();
+
+                if let Some(ref x) = group.prefix {
+                    let _ = write!(desc, "Prefix: {}\n", x);
+                }
+
+                let mut no_commands = true;
+
+                for (n, cmd) in remove_aliases(&group.commands) {
+                    if cmd.help_available {
+                        let _ = write!(desc, "`{}`\n", n);
+
+                        no_commands = false;
+                    }
+                }
+
+                if no_commands {
+                    let _ = write!(desc, "*[No commands]*");
+                }
+
+                e = e.field(|f| f.name(&group_name).value(&desc));
+            }
+
+            e
+        }));
+
+    Ok(())
+}
+
+pub fn plain(ctx: &mut Context,
+             _: &Message,
+             groups: HashMap<String, Arc<CommandGroup>>,
+             args: &[String]) -> Result<(), String> {
+    if !args.is_empty() {
+        let name = args.join(" ");
+
+        for (group_name, group) in groups {
+            let mut found: Option<(&String, &Command)> = None;
+
+            for (command_name, command) in &group.commands {
+                let with_prefix = if let Some(ref prefix) = group.prefix {
+                    format!("{} {}", prefix, command_name)
+                } else {
+                    command_name.to_owned()
+                };
+
+                if name == with_prefix || name == *command_name  {
+                    match *command {
+                        CommandOrAlias::Command(ref cmd) => {
+                            found = Some((command_name, cmd));
+                        },
+                        CommandOrAlias::Alias(ref name) => {
+                            let _ = ctx.channel_id.unwrap().say(&format!("Did you mean {:?}?", name));
+                            return Ok(());
+                        }
+                    }
+                }
+            }
+
+            if let Some((command_name, command)) = found {
+                if !command.help_available {
+                    let _ = ctx.channel_id.unwrap().say("**Error**: No help available.");
+                    return Ok(());
+                }
+
+                let mut result = format!("**{}**\n", command_name);
+
+                if let Some(ref desc) = command.desc {
+                    let _ = write!(result, "**Description:** {}\n", desc);
+                }
+
+                if let Some(ref usage) = command.usage {
+                    let _ = write!(result, "**Usage:** `{} {}`\n", command_name, usage);
+                }
+
+                if let Some(ref example) = command.example {
+                    let _ = write!(result, "**Sample usage:** `{} {}`\n", command_name, example);
+                }
+
+                if group_name != "Ungrouped" {
+                    let _ = write!(result, "**Group:** {}\n", group_name);
+                }
+
+                result.push_str("**Available:** ");
+                result.push_str(if command.dm_only {
+                    "Only in DM"
+                } else if command.guild_only {
+                    "Only in guilds"
+                } else {
+                    "In DM and guilds"
+                });
+                result.push_str("\n");
+
+                let _ = ctx.channel_id.unwrap().say(&result);
+
+                return Ok(());
+            }
+        }
+
+        let _ = ctx.channel_id.unwrap().say(&format!("**Error**: Command `{}` not found.", name));
+
+        return Ok(());
+    }
+
+    let mut result = "**Commands**\nTo get help with an individual command, pass its \
+                      name as an argument to this command.\n\n"
+        .to_string();
+
+    for (group_name, group) in groups {
+        let _ = write!(result, "**{}:** ", group_name);
+
+        if let Some(ref x) = group.prefix {
+            let _ = write!(result, "(prefix: `{}`): ", x);
+        }
+
+        let mut no_commands = true;
+
+        for (n, cmd) in remove_aliases(&group.commands) {
+            if cmd.help_available {
+                let _ = write!(result, "`{}` ", n);
+
+                no_commands = false;
+            }
+        }
+
+        if no_commands {
+            result.push_str("*[No Commands]*");
+        }
+
+        result.push('\n');
+    }
+
+    let _ = ctx.channel_id.unwrap().say(&result);
+
+    Ok(())
+}