use std::{env, error::Error, sync::Arc};

use confindent::Confindent;
use database::{BoardRow, Database, Error as DbError, PermissionSetting};
use twilight_cache_inmemory::{DefaultInMemoryCache, ResourceType};
use twilight_gateway::{Event, EventTypeFlags, Intents, Shard, ShardId, StreamExt};
use twilight_http::{Client as HttpClient, client::InteractionClient};
use twilight_model::{
	application::{
		command::{Command, CommandType},
		interaction::{
			InteractionData,
			application_command::{CommandData, CommandDataOption, CommandOptionValue},
		},
	},
	channel::message::MessageFlags,
	gateway::payload::incoming::InteractionCreate,
	http::interaction::{InteractionResponse, InteractionResponseData, InteractionResponseType},
	id::{
		Id,
		marker::{GuildMarker, InteractionMarker, UserMarker},
	},
};
use twilight_util::builder::{
	InteractionResponseDataBuilder,
	command::{
		CommandBuilder, IntegerBuilder, MentionableBuilder, NumberBuilder, RoleBuilder,
		StringBuilder, SubCommandBuilder, SubCommandGroupBuilder, UserBuilder,
	},
	embed::{EmbedBuilder, EmbedFieldBuilder},
};

mod database;

const APP_ID: u64 = 1363055126264283136;

macro_rules! bail {
	($msg:expr) => {
		return InteractionResponseDataBuilder::new()
			.content(&format!("❌ {}", $msg))
			.build()
	};
}

macro_rules! fail {
	($msg:expr) => {
		InteractionResponseDataBuilder::new()
			.content(&format!("❌ {}", $msg))
			.build()
	};
}

macro_rules! success {
	($msg:expr) => {
		InteractionResponseDataBuilder::new()
			.content(&format!("✅ {}", $msg))
			.build()
	};
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
	dotenv::dotenv().ok();

	let conf = Confindent::from_file("/etc/leaberblord.conf").unwrap();
	let db_dir = conf
		.child_owned("Database")
		.unwrap_or("/var/leaberblord/leaberblord.sqlite".to_string());
	let token = env::var("DISCORD_TOKEN")
		.ok()
		.unwrap_or_else(|| conf.child_owned("DiscordToken").unwrap());

	let db = Arc::new(Database::new(db_dir));
	db.create_tables();

	let mut shard = Shard::new(ShardId::ONE, token.clone(), Intents::GUILD_MESSAGES);
	let http = Arc::new(HttpClient::new(token));
	let mut cache = DefaultInMemoryCache::builder()
		.resource_types(ResourceType::MESSAGE)
		.resource_types(ResourceType::MEMBER)
		.build();

	let iclient = http.interaction(Id::new(APP_ID));
	let commands_vec = commands().await;
	iclient.set_global_commands(&commands_vec).await.unwrap();

	println!("Set commands!");

	let cmd_ap_global = iclient
		.global_commands()
		.await
		.unwrap()
		.models()
		.await
		.unwrap();

	for cmd in cmd_ap_global {
		println!(
			"global command- [{}] {}: {}",
			cmd.id
				.map(|c| c.get().to_string())
				.unwrap_or("-".to_owned()),
			cmd.name,
			cmd.description
		);
	}

	while let Some(item) = shard.next_event(EventTypeFlags::all()).await {
		let Ok(event) = item else {
			eprintln!("error receiving event");
			continue;
		};

		cache.update(&event);

		tokio::spawn(handle_event(event, Arc::clone(&http), Arc::clone(&db)));
	}

	Ok(())
}

async fn handle_event(
	event: Event,
	http: Arc<HttpClient>,
	db: Arc<Database>,
) -> Result<(), Box<dyn Error + Send + Sync>> {
	match event {
		Event::InteractionCreate(create) => {
			// Don't allow direct message commanding
			if create.is_dm() {
				let iclient = http.interaction(Id::new(APP_ID));
				iclient
					.create_response(
						create.id,
						&create.token,
						&InteractionResponse {
							kind: InteractionResponseType::ChannelMessageWithSource,
							data: Some(fail!("leaderboards not supported in DMs")),
						},
					)
					.await
					.unwrap();
			}

			let data = create.data.as_ref().unwrap();

			if let InteractionData::ApplicationCommand(cmd) = data {
				let guild = create.guild.as_ref().unwrap().id.unwrap();

				let command = match cmd.name.as_str() {
					"leaderboard" => Commands::Leaderboard,
					"points" => Commands::Points,
					"permission" => Commands::Permission,
					_ => panic!("'{}' is not a command", cmd.name),
				};

				command_handler(&db, http, guild, &create, command, cmd).await;
			}
		}
		Event::GatewayClose(close) => {
			println!("GatewayClose - {close:?}")
		}
		_ => (),
	}

	Ok(())
}

async fn commands() -> Vec<Command> {
	let leaderboard = CommandBuilder::new(
		"leaderboard",
		"View the server leaderboard",
		CommandType::ChatInput,
	)
	.build();

	let points = CommandBuilder::new("points", "Add and remove points!", CommandType::ChatInput)
		.option(IntegerBuilder::new("points", "number of points. - or +").required(true))
		.option(
			StringBuilder::new("users", "mention people to modify their points!!").required(true),
		)
		.validate()
		.unwrap()
		.build();

	let permission = CommandBuilder::new(
		"permission",
		"set who is allowed to change points",
		CommandType::ChatInput,
	)
	.option(
		SubCommandBuilder::new("role", "require a role to change the score")
			.option(RoleBuilder::new("role", "role required").required(true)),
	)
	.option(SubCommandBuilder::new(
		"none",
		"anyone can change the score",
	))
	.build();

	vec![leaderboard, points, permission]
}

async fn command_handler(
	db: &Database,
	http: Arc<HttpClient>,
	guild: Id<GuildMarker>,
	create: &InteractionCreate,
	command: Commands,
	command_data: &CommandData,
) {
	// Handle the command and create our interaction response data
	let data = match command {
		Commands::Leaderboard => get_leaderboard(&db, guild),
		Commands::Points => add_points(&db, &http, guild, create, command_data).await,
		Commands::Permission => permission(&db, &http, guild, create, command_data).await,
	};

	// Finally, send back the response
	http.interaction(Id::new(APP_ID))
		.create_response(
			create.id,
			&create.token,
			&InteractionResponse {
				kind: InteractionResponseType::ChannelMessageWithSource,
				data: Some(data),
			},
		)
		.await
		.unwrap();
}

fn get_leaderboard(db: &Database, guild: Id<GuildMarker>) -> InteractionResponseData {
	let board = db.get_leaderboard(guild.get());

	match board {
		Err(DbError::TableNotExist) => {
			fail!("No leaderboard exists for this server! Create one by giving someone points.")
		}
		Err(DbError::UserNotExist) => unreachable!(),
		Ok(data) => {
			let str = data
				.into_iter()
				.enumerate()
				.map(|(idx, br)| format!("{idx}. <@{}>: {}", br.user_id, br.points))
				.collect::<Vec<String>>()
				.join("\n");

			let embed = EmbedBuilder::new().description(str).build();

			InteractionResponseDataBuilder::new()
				.embeds([embed])
				.build()
		}
	}
}

// A Absolutely Remarkably Terrible Thing
macro_rules! aumau {
	($meow:expr) => {
		$meow.await.unwrap().model().await.unwrap()
	};
}

async fn add_points(
	db: &Database,
	http: &HttpClient,
	guild: Id<GuildMarker>,
	create: &InteractionCreate,
	data: &CommandData,
) -> InteractionResponseData {
	let mut points = None;
	let mut users: Vec<Id<UserMarker>> = vec![];

	for opt in &data.options {
		match opt.name.as_str() {
			"points" => match opt.value {
				CommandOptionValue::Integer(num) => points = Some(num),
				_ => unreachable!(),
			},
			"users" => match &opt.value {
				CommandOptionValue::String(raw) => {
					println!("raw: {raw}");
					let mentions = extract_mentions(&raw);
					users = mentions;
				}
				_ => unreachable!(),
			},
			_ => unreachable!(),
		}
	}

	let (points, points_display, points_verb) = match points {
		Some(p) if p > 0 => (p, p, "added to"),
		Some(p) if p <= 0 => (p, -p, "removed from"),
		Some(_) | None => unreachable!(),
	};

	// Make sure we have a leaderboard to work on.
	if db.get_leaderboard(guild.get()).is_err() {
		db.create_leaderboard(guild.get()).unwrap();
	}

	let settings = db.get_leaderboard_settings(guild.get()).unwrap();
	if let PermissionSetting::RoleRequired = settings.permission {
		if let Some(role) = settings.role {
			let member = create.member.clone().unwrap();
			let found_role = member.roles.iter().find(|vrole| vrole.get() == role);

			if found_role.is_none() {
				bail!("You do not have the right permissions to change the score");
			}
		} else {
			// Seeing as the role is a required input on the subcommand, this
			// would only happen with direct database fiddling or like, some
			// really weird arcane bullshit?
			bail!(
				"Permissions set to Role Required, but no role is set. \
				This shouldn't be able to happen. \
				Maybe try to set the permissions again?"
			);
		}
	}

	for user in &users {
		match db.give_user_points(guild.get(), user.get(), points) {
			Err(DbError::UserNotExist) => {
				let member = aumau!(http.guild_member(guild, *user));
				let row = BoardRow {
					user_id: user.get(),
					user_handle: member.user.name,
					user_nickname: member.nick.or(member.user.global_name),
					points,
				};
				db.add_user_to_leaderboard(guild.get(), row).unwrap();
			}
			_ => (),
		}
	}

	let users_string = users
		.into_iter()
		.map(|u| format!("<@{u}>"))
		.collect::<Vec<String>>()
		.join(", ");

	let msg = format!("{points_display} points {points_verb} {users_string}");
	let embed = EmbedBuilder::new().description(msg).build();
	InteractionResponseDataBuilder::new()
		.embeds([embed])
		.build()
}

async fn permission(
	db: &Database,
	http: &HttpClient,
	guild: Id<GuildMarker>,
	create: &InteractionCreate,
	data: &CommandData,
) -> InteractionResponseData {
	let member = create.member.clone().unwrap();
	let permissions = member.permissions.unwrap();
	if !permissions.contains(twilight_model::guild::Permissions::MANAGE_GUILD) {
		bail!("You must have the Manage Server permission to perform this command");
	}

	for opt in &data.options {
		return match opt.name.as_str() {
			"none" => permission_none(db, guild),
			"role" => permission_role(db, guild, opt.value.clone()),
			_ => panic!(),
		};
	}

	fail!("this should be unreachable. report the bug maybe? to gennyble on discord")
}

fn permission_none(db: &Database, guild: Id<GuildMarker>) -> InteractionResponseData {
	if db.get_leaderboard(guild.get()).is_err() {
		db.create_leaderboard(guild.get()).unwrap();
	} else {
		db.set_leaderboard_permission(guild.get(), PermissionSetting::None)
			.unwrap();
	}

	success!("Permission for leaderboard changed to none. Anyone may now set the score.")
}

fn permission_role(
	db: &Database,
	guild: Id<GuildMarker>,
	data: CommandOptionValue,
) -> InteractionResponseData {
	let role = if let CommandOptionValue::SubCommand(data) = data {
		match data.iter().find(|d| d.name == "role").unwrap().value {
			CommandOptionValue::Role(role) => role,
			_ => panic!(),
		}
	} else {
		panic!()
	};

	// Make sure we have a leaderboard to work on
	if db.get_leaderboard(guild.get()).is_err() {
		db.create_leaderboard(guild.get()).unwrap();
	}

	db.set_leaderboard_permission(guild.get(), PermissionSetting::RoleRequired)
		.unwrap();
	db.set_leaderboard_permission_role(guild.get(), role.get())
		.unwrap();

	success!(format!(
		"Permission for leaderboard changed to Role Required. \
		Only members of <@&{role}> may now set the score"
	))
}

enum Commands {
	Leaderboard,
	Points,
	Permission,
}

fn extract_mentions(mut raw: &str) -> Vec<Id<UserMarker>> {
	let mut ret = vec![];

	loop {
		let Some(start) = raw.find("<@") else {
			break;
		};

		let Some(end) = raw.find('>') else {
			break;
		};

		let id_str = &raw[start + 2..end];
		raw = &raw[end + 1..];

		let Ok(id) = u64::from_str_radix(id_str, 10) else {
			continue;
		};

		ret.push(Id::new(id));
	}

	ret
}