use std::collections::HashMap;

use anyhow::Result;
use bytes::Bytes;
use log::*;
use reqwest::StatusCode;
use serde::{Deserialize, Serialize};

// ---- Watch and retrieve Consul catalog ----
//
#[derive(Serialize, Deserialize, Debug)]
pub struct ConsulNode {
	#[serde(rename = "Node")]
	pub node: String,
	#[serde(rename = "Address")]
	pub address: String,
}

#[derive(Serialize, Deserialize, Debug)]
pub struct ConsulServiceEntry {
	#[serde(rename = "Service")]
	pub service: String,

	#[serde(rename = "Address")]
	pub address: String,

	#[serde(rename = "Port")]
	pub port: u16,

	#[serde(rename = "Tags")]
	pub tags: Vec<String>,
}

#[derive(Serialize, Deserialize, Debug)]
pub struct ConsulNodeCatalog {
	#[serde(rename = "Node")]
	pub node: ConsulNode,
	#[serde(rename = "Services")]
	pub services: HashMap<String, ConsulServiceEntry>,
}

// ---- Consul session management ----

#[derive(Serialize, Deserialize, Debug)]
pub struct ConsulSessionRequest {
	#[serde(rename = "Name")]
	pub name: String,

	#[serde(rename = "Node")]
	pub node: Option<String>,

	#[serde(rename = "LockDelay")]
	pub lock_delay: Option<String>,

	#[serde(rename = "TTL")]
	pub ttl: Option<String>,

	#[serde(rename = "Behavior")]
	pub behavior: Option<String>,
}

#[derive(Serialize, Deserialize, Debug)]
pub struct ConsulSessionResponse {
	#[serde(rename = "ID")]
	pub id: String,
}

#[derive(Clone)]
pub struct Consul {
	client: reqwest::Client,

	url: String,
	kv_prefix: String,

	pub local_node: String,
}

impl Consul {
	pub fn new(url: &str, kv_prefix: &str, local_node: &str) -> Self {
		return Self {
			client: reqwest::Client::new(),
			url: url.to_string(),
			kv_prefix: kv_prefix.to_string(),
			local_node: local_node.into(),
		};
	}

	pub async fn list_nodes(&self) -> Result<Vec<String>> {
		debug!("list_nodes");

		let url = format!("{}/v1/catalog/nodes", self.url);

		let http = self.client.get(&url).send().await?;
		let resp: Vec<ConsulNode> = http.json().await?;
		Ok(resp.into_iter().map(|n| n.node).collect::<Vec<_>>())
	}

	pub async fn watch_node(
		&self,
		host: &str,
		idx: Option<usize>,
	) -> Result<(ConsulNodeCatalog, usize)> {
		debug!("watch_node {} {:?}", host, idx);

		let url = match idx {
			Some(i) => format!("{}/v1/catalog/node/{}?index={}", self.url, host, i),
			None => format!("{}/v1/catalog/node/{}", self.url, host),
		};

		let http = self.client.get(&url).send().await?;
		let new_idx = match http.headers().get("X-Consul-Index") {
			Some(v) => v.to_str()?.parse::<usize>()?,
			None => bail!("X-Consul-Index header not found"),
		};

		let resp: ConsulNodeCatalog = http.json().await?;
		return Ok((resp, new_idx));
	}

	// ---- KV get and put ----

	pub async fn kv_get(&self, key: &str) -> Result<Option<Bytes>> {
		debug!("kv_get {}", key);

		let url = format!("{}/v1/kv/{}{}?raw", self.url, self.kv_prefix, key);
		let http = self.client.get(&url).send().await?;
		match http.status() {
			StatusCode::OK => Ok(Some(http.bytes().await?)),
			StatusCode::NOT_FOUND => Ok(None),
			_ => Err(anyhow!(
				"Consul request failed: {:?}",
				http.error_for_status()
			)),
		}
	}

	pub async fn kv_get_json<T: for<'de> Deserialize<'de>>(&self, key: &str) -> Result<Option<T>> {
		debug!("kv_get_json {}", key);

		let url = format!("{}/v1/kv/{}{}?raw", self.url, self.kv_prefix, key);
		let http = self.client.get(&url).send().await?;
		match http.status() {
			StatusCode::OK => Ok(Some(http.json().await?)),
			StatusCode::NOT_FOUND => Ok(None),
			_ => Err(anyhow!(
				"Consul request failed: {:?}",
				http.error_for_status()
			)),
		}
	}

	pub async fn kv_put(&self, key: &str, bytes: Bytes) -> Result<()> {
		debug!("kv_put {}", key);

		let url = format!("{}/v1/kv/{}{}", self.url, self.kv_prefix, key);
		let http = self.client.put(&url).body(bytes).send().await?;
		http.error_for_status()?;
		Ok(())
	}

	pub async fn kv_put_json<T: Serialize>(&self, key: &str, value: &T) -> Result<()> {
		debug!("kv_put_json {}", key);

		let url = format!("{}/v1/kv/{}{}", self.url, self.kv_prefix, key);
		let http = self.client.put(&url).json(value).send().await?;
		http.error_for_status()?;
		Ok(())
	}

	pub async fn kv_delete(&self, key: &str) -> Result<()> {
		let url = format!("{}/v1/kv/{}{}", self.url, self.kv_prefix, key);
		let http = self.client.delete(&url).send().await?;
		http.error_for_status()?;
		Ok(())
	}

	// ---- Locking ----

	pub async fn create_session(&self, req: &ConsulSessionRequest) -> Result<String> {
		debug!("create_session {:?}", req);

		let url = format!("{}/v1/session/create", self.url);
		let http = self.client.put(&url).json(req).send().await?;
		let resp: ConsulSessionResponse = http.json().await?;
		Ok(resp.id)
	}

	pub async fn acquire(&self, key: &str, bytes: Bytes, session: &str) -> Result<bool> {
		debug!("acquire {}", key);

		let url = format!(
			"{}/v1/kv/{}{}?acquire={}",
			self.url, self.kv_prefix, key, session
		);
		let http = self.client.put(&url).body(bytes).send().await?;
		let resp: bool = http.json().await?;
		Ok(resp)
	}

	pub async fn release(&self, key: &str, bytes: Bytes, session: &str) -> Result<()> {
		debug!("release {}", key);

		let url = format!(
			"{}/v1/kv/{}{}?release={}",
			self.url, self.kv_prefix, key, session
		);
		let http = self.client.put(&url).body(bytes).send().await?;
		http.error_for_status()?;
		Ok(())
	}
}