use std::{
	collections::BTreeMap,
	fmt,
	fmt::Write as _,
	net::{IpAddr, Ipv4Addr},
	path::PathBuf,
};

use either::Either;
use figment::Figment;
use itertools::Itertools;
use regex::RegexSet;
use ruma::{OwnedServerName, RoomVersionId};
use serde::{de::IgnoredAny, Deserialize};
use tracing::{debug, error, warn};

use self::proxy::ProxyConfig;

mod proxy;

#[derive(Deserialize, Clone, Debug)]
#[serde(transparent)]
pub struct ListeningPort {
	#[serde(with = "either::serde_untagged")]
	pub ports: Either<u16, Vec<u16>>,
}

/// all the config options for conduwuit
#[derive(Clone, Debug, Deserialize)]
pub struct Config {
	/// [`IpAddr`] conduwuit will listen on (can be IPv4 or IPv6)
	#[serde(default = "default_address")]
	pub address: IpAddr,
	/// default TCP port(s) conduwuit will listen on
	#[serde(default = "default_port")]
	pub port: ListeningPort,
	pub tls: Option<TlsConfig>,
	pub unix_socket_path: Option<PathBuf>,
	#[serde(default = "default_unix_socket_perms")]
	pub unix_socket_perms: u32,
	pub server_name: OwnedServerName,
	#[serde(default = "default_database_backend")]
	pub database_backend: String,
	pub database_path: String,
	#[serde(default = "default_db_cache_capacity_mb")]
	pub db_cache_capacity_mb: f64,
	#[serde(default = "default_new_user_displayname_suffix")]
	pub new_user_displayname_suffix: String,
	#[serde(default = "true_fn")]
	pub allow_check_for_updates: bool,
	#[serde(default = "default_conduit_cache_capacity_modifier")]
	pub conduit_cache_capacity_modifier: f64,
	#[serde(default = "default_pdu_cache_capacity")]
	pub pdu_cache_capacity: u32,
	#[serde(default = "default_cleanup_second_interval")]
	pub cleanup_second_interval: u32,
	#[serde(default = "default_max_request_size")]
	pub max_request_size: u32,
	#[serde(default = "default_max_concurrent_requests")]
	pub max_concurrent_requests: u16,
	#[serde(default = "default_max_fetch_prev_events")]
	pub max_fetch_prev_events: u16,
	#[serde(default)]
	pub allow_registration: bool,
	#[serde(default)]
	pub yes_i_am_very_very_sure_i_want_an_open_registration_server_prone_to_abuse: bool,
	pub registration_token: Option<String>,
	#[serde(default = "true_fn")]
	pub allow_encryption: bool,
	#[serde(default = "true_fn")]
	pub allow_federation: bool,
	#[serde(default)]
	pub allow_public_room_directory_over_federation: bool,
	#[serde(default)]
	pub allow_public_room_directory_without_auth: bool,
	#[serde(default)]
	pub allow_device_name_federation: bool,
	#[serde(default = "true_fn")]
	pub allow_room_creation: bool,
	#[serde(default = "true_fn")]
	pub allow_unstable_room_versions: bool,
	#[serde(default = "default_default_room_version")]
	pub default_room_version: RoomVersionId,
	pub well_known_client: Option<String>,
	pub well_known_server: Option<String>,
	#[serde(default)]
	pub allow_jaeger: bool,
	#[serde(default)]
	pub tracing_flame: bool,
	#[serde(default)]
	pub proxy: ProxyConfig,
	pub jwt_secret: Option<String>,
	#[serde(default = "default_trusted_servers")]
	pub trusted_servers: Vec<OwnedServerName>,
	#[serde(default = "true_fn")]
	pub query_trusted_key_servers_first: bool,
	#[serde(default = "default_log")]
	pub log: String,
	#[serde(default)]
	pub turn_username: String,
	#[serde(default)]
	pub turn_password: String,
	#[serde(default = "Vec::new")]
	pub turn_uris: Vec<String>,
	#[serde(default)]
	pub turn_secret: String,
	#[serde(default = "default_turn_ttl")]
	pub turn_ttl: u64,

	#[serde(default = "default_rocksdb_log_level")]
	pub rocksdb_log_level: String,
	#[serde(default = "default_rocksdb_max_log_file_size")]
	pub rocksdb_max_log_file_size: usize,
	#[serde(default = "default_rocksdb_log_time_to_roll")]
	pub rocksdb_log_time_to_roll: usize,
	#[serde(default)]
	pub rocksdb_optimize_for_spinning_disks: bool,
	#[serde(default = "default_rocksdb_parallelism_threads")]
	pub rocksdb_parallelism_threads: usize,
	#[serde(default = "default_rocksdb_max_log_files")]
	pub rocksdb_max_log_files: usize,

	pub emergency_password: Option<String>,

	#[serde(default = "default_notification_push_path")]
	pub notification_push_path: String,

	#[serde(default)]
	pub allow_local_presence: bool,
	#[serde(default)]
	pub allow_incoming_presence: bool,
	#[serde(default)]
	pub allow_outgoing_presence: bool,
	#[serde(default = "default_presence_idle_timeout_s")]
	pub presence_idle_timeout_s: u64,
	#[serde(default = "default_presence_offline_timeout_s")]
	pub presence_offline_timeout_s: u64,

	#[serde(default)]
	pub zstd_compression: bool,

	#[serde(default)]
	pub allow_guest_registration: bool,

	#[serde(default = "Vec::new")]
	pub prevent_media_downloads_from: Vec<OwnedServerName>,

	#[serde(default = "default_ip_range_denylist")]
	pub ip_range_denylist: Vec<String>,

	#[serde(default = "Vec::new")]
	pub url_preview_domain_contains_allowlist: Vec<String>,
	#[serde(default = "Vec::new")]
	pub url_preview_domain_explicit_allowlist: Vec<String>,
	#[serde(default = "Vec::new")]
	pub url_preview_url_contains_allowlist: Vec<String>,
	#[serde(default = "default_url_preview_max_spider_size")]
	pub url_preview_max_spider_size: usize,
	#[serde(default)]
	pub url_preview_check_root_domain: bool,

	#[serde(default = "RegexSet::empty")]
	#[serde(with = "serde_regex")]
	pub forbidden_room_names: RegexSet,

	#[serde(default = "RegexSet::empty")]
	#[serde(with = "serde_regex")]
	pub forbidden_usernames: RegexSet,

	#[serde(default)]
	pub block_non_admin_invites: bool,

	#[serde(flatten)]
	pub catchall: BTreeMap<String, IgnoredAny>,
}

#[derive(Clone, Debug, Deserialize)]
pub struct TlsConfig {
	pub certs: String,
	pub key: String,
	#[serde(default)]
	/// Whether to listen and allow for HTTP and HTTPS connections (insecure!)
	/// Only works / does something if the `axum_dual_protocol` feature flag was
	/// built
	pub dual_protocol: bool,
}

const DEPRECATED_KEYS: &[&str] = &["cache_capacity"];

impl Config {
	/// Iterates over all the keys in the config file and warns if there is a
	/// deprecated key specified
	pub fn warn_deprecated(&self) {
		debug!("Checking for deprecated config keys");
		let mut was_deprecated = false;
		for key in self.catchall.keys().filter(|key| DEPRECATED_KEYS.iter().any(|s| s == key)) {
			warn!("Config parameter \"{}\" is deprecated, ignoring.", key);
			was_deprecated = true;
		}

		if was_deprecated {
			warn!(
				"Read conduit documentation and check your configuration if any new configuration parameters should \
				 be adjusted"
			);
		}
	}

	/// iterates over all the catchall keys (unknown config options) and warns
	/// if there are any.
	pub fn warn_unknown_key(&self) {
		debug!("Checking for unknown config keys");
		for key in
			self.catchall.keys().filter(|key| "config".to_owned().ne(key.to_owned()) /* "config" is expected */)
		{
			warn!("Config parameter \"{}\" is unknown to conduwuit, ignoring.", key);
		}
	}

	/// Checks the presence of the `address` and `unix_socket_path` keys in the
	/// raw_config, exiting the process if both keys were detected.
	pub fn is_dual_listening(&self, raw_config: &Figment) -> bool {
		let check_address = raw_config.find_value("address");
		let check_unix_socket = raw_config.find_value("unix_socket_path");

		// are the check_address and check_unix_socket keys both Ok (specified) at the
		// same time?
		if check_address.is_ok() && check_unix_socket.is_ok() {
			error!("TOML keys \"address\" and \"unix_socket_path\" were both defined. Please specify only one option.");
			return true;
		}

		false
	}
}

impl fmt::Display for Config {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		// Prepare a list of config values to show
		let lines = [
			("Server name", self.server_name.host()),
			("Database backend", &self.database_backend),
			("Database path", &self.database_path),
			("Database cache capacity (MB)", &self.db_cache_capacity_mb.to_string()),
			("Cache capacity modifier", &self.conduit_cache_capacity_modifier.to_string()),
			("PDU cache capacity", &self.pdu_cache_capacity.to_string()),
			("Cleanup interval in seconds", &self.cleanup_second_interval.to_string()),
			("Maximum request size (bytes)", &self.max_request_size.to_string()),
			("Maximum concurrent requests", &self.max_concurrent_requests.to_string()),
			("Allow registration", &self.allow_registration.to_string()),
			(
				"Registration token",
				match self.registration_token {
					Some(_) => "set",
					None => "not set (open registration!)",
				},
			),
			(
				"Allow guest registration (inherently false if allow registration is false)",
				&self.allow_guest_registration.to_string(),
			),
			("New user display name suffix", &self.new_user_displayname_suffix),
			("Allow encryption", &self.allow_encryption.to_string()),
			("Allow federation", &self.allow_federation.to_string()),
			(
				"Allow incoming federated presence requests (updates)",
				&self.allow_incoming_presence.to_string(),
			),
			(
				"Allow outgoing federated presence requests (updates)",
				&self.allow_outgoing_presence.to_string(),
			),
			(
				"Allow local presence requests (updates)",
				&self.allow_local_presence.to_string(),
			),
			(
				"Block non-admin room invites (local and remote, admins can still send and receive invites)",
				&self.block_non_admin_invites.to_string(),
			),
			("Allow device name federation", &self.allow_device_name_federation.to_string()),
			("Notification push path", &self.notification_push_path),
			("Allow room creation", &self.allow_room_creation.to_string()),
			(
				"Allow public room directory over federation",
				&self.allow_public_room_directory_over_federation.to_string(),
			),
			(
				"Allow public room directory without authentication",
				&self.allow_public_room_directory_without_auth.to_string(),
			),
			(
				"JWT secret",
				match self.jwt_secret {
					Some(_) => "set",
					None => "not set",
				},
			),
			("Trusted key servers", {
				let mut lst = vec![];
				for server in &self.trusted_servers {
					lst.push(server.host());
				}
				&lst.join(", ")
			}),
			(
				"Query Trusted Key Servers First",
				&self.query_trusted_key_servers_first.to_string(),
			),
			(
				"TURN username",
				if self.turn_username.is_empty() {
					"not set"
				} else {
					&self.turn_username
				},
			),
			("TURN password", {
				if self.turn_password.is_empty() {
					"not set"
				} else {
					"set"
				}
			}),
			("TURN secret", {
				if self.turn_secret.is_empty() {
					"not set"
				} else {
					"set"
				}
			}),
			("Turn TTL", &self.turn_ttl.to_string()),
			("Turn URIs", {
				let mut lst = vec![];
				for item in self.turn_uris.iter().cloned().enumerate() {
					let (_, uri): (usize, String) = item;
					lst.push(uri);
				}
				&lst.join(", ")
			}),
			("zstd Response Body Compression", &self.zstd_compression.to_string()),
			("RocksDB database log level", &self.rocksdb_log_level),
			("RocksDB database log time-to-roll", &self.rocksdb_log_time_to_roll.to_string()),
			("RocksDB Max LOG Files", &self.rocksdb_max_log_files.to_string()),
			(
				"RocksDB database max log file size",
				&self.rocksdb_max_log_file_size.to_string(),
			),
			(
				"RocksDB database optimize for spinning disks",
				&self.rocksdb_optimize_for_spinning_disks.to_string(),
			),
			("RocksDB Parallelism Threads", &self.rocksdb_parallelism_threads.to_string()),
			("Prevent Media Downloads From", {
				let mut lst = vec![];
				for domain in &self.prevent_media_downloads_from {
					lst.push(domain.host());
				}
				&lst.join(", ")
			}),
			("Outbound Request IP Range Denylist", {
				let mut lst = vec![];
				for item in self.ip_range_denylist.iter().cloned().enumerate() {
					let (_, ip): (usize, String) = item;
					lst.push(ip);
				}
				&lst.join(", ")
			}),
			("Forbidden usernames", {
				&self.forbidden_usernames.patterns().iter().join(", ")
			}),
			("Forbidden room names", {
				&self.forbidden_room_names.patterns().iter().join(", ")
			}),
			(
				"URL preview domain contains allowlist",
				&self.url_preview_domain_contains_allowlist.join(", "),
			),
			(
				"URL preview domain explicit allowlist",
				&self.url_preview_domain_explicit_allowlist.join(", "),
			),
			(
				"URL preview URL contains allowlist",
				&self.url_preview_url_contains_allowlist.join(", "),
			),
			("URL preview maximum spider size", &self.url_preview_max_spider_size.to_string()),
			("URL preview check root domain", &self.url_preview_check_root_domain.to_string()),
		];

		let mut msg: String = "Active config values:\n\n".to_owned();

		for line in lines.into_iter().enumerate() {
			let _ = writeln!(msg, "{}: {}", line.1 .0, line.1 .1);
		}

		write!(f, "{msg}")
	}
}

fn true_fn() -> bool { true }

fn default_address() -> IpAddr { Ipv4Addr::LOCALHOST.into() }

fn default_port() -> ListeningPort {
	ListeningPort {
		ports: Either::Left(8008),
	}
}

fn default_unix_socket_perms() -> u32 { 660 }

fn default_database_backend() -> String { "rocksdb".to_owned() }

fn default_db_cache_capacity_mb() -> f64 { 300.0 }

fn default_conduit_cache_capacity_modifier() -> f64 { 1.0 }

fn default_pdu_cache_capacity() -> u32 { 150_000 }

fn default_cleanup_second_interval() -> u32 {
	1800 // every 30 minutes
}

fn default_max_request_size() -> u32 {
	20 * 1024 * 1024 // Default to 20 MB
}

fn default_max_concurrent_requests() -> u16 { 500 }

fn default_max_fetch_prev_events() -> u16 { 100_u16 }

fn default_trusted_servers() -> Vec<OwnedServerName> { vec![OwnedServerName::try_from("matrix.org").unwrap()] }

fn default_log() -> String { "warn,state_res=warn".to_owned() }

fn default_notification_push_path() -> String { "/_matrix/push/v1/notify".to_owned() }

fn default_turn_ttl() -> u64 { 60 * 60 * 24 }

fn default_presence_idle_timeout_s() -> u64 { 5 * 60 }

fn default_presence_offline_timeout_s() -> u64 { 30 * 60 }

fn default_rocksdb_log_level() -> String { "error".to_owned() }

fn default_rocksdb_log_time_to_roll() -> usize { 0 }

fn default_rocksdb_max_log_files() -> usize { 3 }

fn default_rocksdb_parallelism_threads() -> usize { num_cpus::get_physical() / 2 }

// I know, it's a great name
pub(crate) fn default_default_room_version() -> RoomVersionId { RoomVersionId::V10 }

fn default_rocksdb_max_log_file_size() -> usize {
	// 4 megabytes
	4 * 1024 * 1024
}

fn default_ip_range_denylist() -> Vec<String> {
	vec![
		"127.0.0.0/8".to_owned(),
		"10.0.0.0/8".to_owned(),
		"172.16.0.0/12".to_owned(),
		"192.168.0.0/16".to_owned(),
		"100.64.0.0/10".to_owned(),
		"192.0.0.0/24".to_owned(),
		"169.254.0.0/16".to_owned(),
		"192.88.99.0/24".to_owned(),
		"198.18.0.0/15".to_owned(),
		"192.0.2.0/24".to_owned(),
		"198.51.100.0/24".to_owned(),
		"203.0.113.0/24".to_owned(),
		"224.0.0.0/4".to_owned(),
		"::1/128".to_owned(),
		"fe80::/10".to_owned(),
		"fc00::/7".to_owned(),
		"2001:db8::/32".to_owned(),
		"ff00::/8".to_owned(),
		"fec0::/10".to_owned(),
	]
}

fn default_url_preview_max_spider_size() -> usize {
	1_000_000 // 1MB
}

fn default_new_user_displayname_suffix() -> String { "🏳️‍⚧️".to_owned() }