use clap::Subcommand;
use ruma::{api::appservice::Registration, events::room::message::RoomMessageEventContent};

use crate::{service::admin::escape_html, services, Result};

#[cfg_attr(test, derive(Debug))]
#[derive(Subcommand)]
pub(crate) enum AppserviceCommand {
	/// - Register an appservice using its registration YAML
	///
	/// This command needs a YAML generated by an appservice (such as a bridge),
	/// which must be provided in a Markdown code block below the command.
	///
	/// Registering a new bridge using the ID of an existing bridge will replace
	/// the old one.
	Register,

	/// - Unregister an appservice using its ID
	///
	/// You can find the ID using the `list-appservices` command.
	Unregister {
		/// The appservice to unregister
		appservice_identifier: String,
	},

	/// - Show an appservice's config using its ID
	///
	/// You can find the ID using the `list-appservices` command.
	Show {
		/// The appservice to show
		appservice_identifier: String,
	},

	/// - List all the currently registered appservices
	List,
}

pub(crate) async fn process(command: AppserviceCommand, body: Vec<&str>) -> Result<RoomMessageEventContent> {
	match command {
		AppserviceCommand::Register => {
			if body.len() > 2 && body[0].trim().starts_with("```") && body.last().unwrap().trim() == "```" {
				let appservice_config = body[1..body.len() - 1].join("\n");
				let parsed_config = serde_yaml::from_str::<Registration>(&appservice_config);
				match parsed_config {
					Ok(yaml) => match services().appservice.register_appservice(yaml).await {
						Ok(id) => Ok(RoomMessageEventContent::text_plain(format!(
							"Appservice registered with ID: {id}."
						))),
						Err(e) => Ok(RoomMessageEventContent::text_plain(format!(
							"Failed to register appservice: {e}"
						))),
					},
					Err(e) => Ok(RoomMessageEventContent::text_plain(format!(
						"Could not parse appservice config: {e}"
					))),
				}
			} else {
				Ok(RoomMessageEventContent::text_plain(
					"Expected code block in command body. Add --help for details.",
				))
			}
		},
		AppserviceCommand::Unregister {
			appservice_identifier,
		} => match services().appservice.unregister_appservice(&appservice_identifier).await {
			Ok(()) => Ok(RoomMessageEventContent::text_plain("Appservice unregistered.")),
			Err(e) => Ok(RoomMessageEventContent::text_plain(format!(
				"Failed to unregister appservice: {e}"
			))),
		},
		AppserviceCommand::Show {
			appservice_identifier,
		} => match services().appservice.get_registration(&appservice_identifier).await {
			Some(config) => {
				let config_str = serde_yaml::to_string(&config).expect("config should've been validated on register");
				let output = format!("Config for {}:\n\n```yaml\n{}\n```", appservice_identifier, config_str,);
				let output_html = format!(
					"Config for {}:\n\n<pre><code class=\"language-yaml\">{}</code></pre>",
					escape_html(&appservice_identifier),
					escape_html(&config_str),
				);
				Ok(RoomMessageEventContent::text_html(output, output_html))
			},
			None => Ok(RoomMessageEventContent::text_plain("Appservice does not exist.")),
		},
		AppserviceCommand::List => {
			let appservices = services().appservice.iter_ids().await;
			let output = format!("Appservices ({}): {}", appservices.len(), appservices.join(", "));
			Ok(RoomMessageEventContent::text_plain(output))
		},
	}
}