//! Contains type and functions related to Garage configuration file
use std::io::Read;
use std::net::SocketAddr;
use std::path::PathBuf;

use serde::de::Error as SerdeError;
use serde::{de, Deserialize};

use netapp::util::parse_and_resolve_peer_addr;
use netapp::NodeID;

use crate::error::Error;

/// Represent the whole configuration
#[derive(Deserialize, Debug, Clone)]
pub struct Config {
	/// Path where to store metadata. Should be fast, but low volume
	pub metadata_dir: PathBuf,
	/// Path where to store data. Can be slower, but need higher volume
	pub data_dir: PathBuf,

	/// Size of data blocks to save to disk
	#[serde(default = "default_block_size")]
	pub block_size: usize,

	/// Size of data blocks to save to disk
	#[serde(default = "default_block_manager_background_tranquility")]
	pub block_manager_background_tranquility: u32,

	/// Replication mode. Supported values:
	/// - none, 1 -> no replication
	/// - 2 -> 2-way replication
	/// - 3 -> 3-way replication
	// (we can add more aliases for this later)
	pub replication_mode: String,

	/// Zstd compression level used on data blocks
	#[serde(
		deserialize_with = "deserialize_compression",
		default = "default_compression"
	)]
	pub compression_level: Option<i32>,

	/// RPC secret key: 32 bytes hex encoded
	pub rpc_secret: String,

	/// Address to bind for RPC
	pub rpc_bind_addr: SocketAddr,
	/// Public IP address of this node
	pub rpc_public_addr: Option<SocketAddr>,

	/// Bootstrap peers RPC address
	#[serde(deserialize_with = "deserialize_vec_addr", default)]
	pub bootstrap_peers: Vec<(NodeID, SocketAddr)>,
	/// Consul host to connect to to discover more peers
	pub consul_host: Option<String>,
	/// Consul service name to use
	pub consul_service_name: Option<String>,
	/// Kubernetes namespace the service discovery resources are be created in
	pub kubernetes_namespace: Option<String>,
	/// Service name to filter for in k8s custom resources
	pub kubernetes_service_name: Option<String>,
	/// Skip creation of the garagenodes CRD
	#[serde(default)]
	pub kubernetes_skip_crd: bool,

	/// Sled cache size, in bytes
	#[serde(default = "default_sled_cache_capacity")]
	pub sled_cache_capacity: u64,

	/// Sled flush interval in milliseconds
	#[serde(default = "default_sled_flush_every_ms")]
	pub sled_flush_every_ms: u64,

	/// Configuration for S3 api
	pub s3_api: S3ApiConfig,

	/// Configuration for K2V api
	#[cfg(feature = "k2v")]
	pub k2v_api: Option<K2VApiConfig>,

	/// Configuration for serving files as normal web server
	pub s3_web: WebConfig,

	/// Configuration for the admin API endpoint
	#[serde(default = "Default::default")]
	pub admin: AdminConfig,
}

/// Configuration for S3 api
#[derive(Deserialize, Debug, Clone)]
pub struct S3ApiConfig {
	/// Address and port to bind for api serving
	pub api_bind_addr: SocketAddr,
	/// S3 region to use
	pub s3_region: String,
	/// Suffix to remove from domain name to find bucket. If None,
	/// vhost-style S3 request are disabled
	pub root_domain: Option<String>,
}

/// Configuration for K2V api
#[cfg(feature = "k2v")]
#[derive(Deserialize, Debug, Clone)]
pub struct K2VApiConfig {
	/// Address and port to bind for api serving
	pub api_bind_addr: SocketAddr,
}

/// Configuration for serving files as normal web server
#[derive(Deserialize, Debug, Clone)]
pub struct WebConfig {
	/// Address and port to bind for web serving
	pub bind_addr: SocketAddr,
	/// Suffix to remove from domain name to find bucket
	pub root_domain: String,
}

/// Configuration for the admin and monitoring HTTP API
#[derive(Deserialize, Debug, Clone, Default)]
pub struct AdminConfig {
	/// Address and port to bind for admin API serving
	pub api_bind_addr: Option<SocketAddr>,
	/// Bearer token to use to scrape metrics
	pub metrics_token: Option<String>,
	/// Bearer token to use to access Admin API endpoints
	pub admin_token: Option<String>,
	/// OTLP server to where to export traces
	pub trace_sink: Option<String>,
}

fn default_sled_cache_capacity() -> u64 {
	128 * 1024 * 1024
}
fn default_sled_flush_every_ms() -> u64 {
	2000
}
fn default_block_size() -> usize {
	1048576
}
fn default_block_manager_background_tranquility() -> u32 {
	2
}

/// Read and parse configuration
pub fn read_config(config_file: PathBuf) -> Result<Config, Error> {
	let mut file = std::fs::OpenOptions::new()
		.read(true)
		.open(config_file.as_path())?;

	let mut config = String::new();
	file.read_to_string(&mut config)?;

	Ok(toml::from_str(&config)?)
}

fn deserialize_vec_addr<'de, D>(deserializer: D) -> Result<Vec<(NodeID, SocketAddr)>, D::Error>
where
	D: de::Deserializer<'de>,
{
	let mut ret = vec![];

	for peer in <Vec<&str>>::deserialize(deserializer)? {
		let (pubkey, addrs) = parse_and_resolve_peer_addr(peer).ok_or_else(|| {
			D::Error::custom(format!("Unable to parse or resolve peer: {}", peer))
		})?;
		for ip in addrs {
			ret.push((pubkey, ip));
		}
	}

	Ok(ret)
}

fn default_compression() -> Option<i32> {
	Some(1)
}

fn deserialize_compression<'de, D>(deserializer: D) -> Result<Option<i32>, D::Error>
where
	D: de::Deserializer<'de>,
{
	use std::convert::TryFrom;

	struct OptionVisitor;

	impl<'de> serde::de::Visitor<'de> for OptionVisitor {
		type Value = Option<i32>;
		fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
			formatter.write_str("int or 'none'")
		}

		fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
		where
			E: de::Error,
		{
			if value.eq_ignore_ascii_case("none") {
				Ok(None)
			} else {
				Err(E::custom(format!(
					"Invalid compression level: '{}', should be a number, or 'none'",
					value
				)))
			}
		}

		fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E>
		where
			E: de::Error,
		{
			i32::try_from(v)
				.map(Some)
				.map_err(|_| E::custom("Compression level out of bound".to_owned()))
		}

		fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E>
		where
			E: de::Error,
		{
			i32::try_from(v)
				.map(Some)
				.map_err(|_| E::custom("Compression level out of bound".to_owned()))
		}
	}

	deserializer.deserialize_any(OptionVisitor)
}