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extern crate serde;
extern crate serde_json;
extern crate url;

use reqwest::{Client, Method, RequestBuilder};
use serde::de::DeserializeOwned;
use std::env;
use thiserror::Error;

pub mod api;
pub mod models;

static ENV_NOMAD_BASE: &str = "NOMAD_BASE_URL";
static ENV_NOMAD_PORT: &str = "NOMAD_PORT";
static ENV_NOMAD_API_VERSION: &str = "NOMAD_API_VERSION";

#[derive(Clone, Debug)]
pub struct NomadClient {
    client: Client,
    config: Config,
}

impl NomadClient {
    pub fn new(config: Config) -> Self {
        NomadClient {
            client: Client::new(),
            config,
        }
    }

    pub fn config(&self) -> &Config {
        &self.config
    }

    pub fn get_base_url(&self) -> String {
        format!(
            "{}:{}/{}",
            self.config.base_url, self.config.port, self.config.api_version
        )
    }

    pub fn get_endpoint(&self, endpoint: &str) -> String {
        if endpoint.starts_with('/') {
            return format!("{}{}", self.get_base_url(), endpoint);
        }

        format!("{}/{}", self.get_base_url(), endpoint)
    }

    pub fn request(&self, method: Method, endpoint: &str) -> RequestBuilder {
        self.client.request(method, &self.get_endpoint(endpoint))
    }

    async fn send_plain(&self, req: RequestBuilder) -> Result<String, ClientError> {
        let req_result = req.build();
        if req_result.is_err() {
            return Err(ClientError::RequestError(
                req_result.err().unwrap().to_string(),
            ));
        }

        let req = req_result.unwrap();

        match self.client.execute(req).await {
            Ok(response) => {
                let status = response.status();
                let body_result = response.text().await;

                match body_result {
                    Ok(body) => {
                        if status.is_success() {
                            Ok(body)
                        } else {
                            Err(ClientError::ServerError(status.as_u16(), body))
                        }
                    }
                    Err(err) => Err(ClientError::NetworkError(err.to_string())),
                }
            }
            Err(err) => Err(ClientError::NetworkError(err.to_string())),
        }
    }

    async fn send<TResponse: DeserializeOwned>(
        &self,
        req: RequestBuilder,
    ) -> Result<TResponse, ClientError> {
        let req_result = req.build();
        if req_result.is_err() {
            return Err(ClientError::RequestError(
                req_result.err().unwrap().to_string(),
            ));
        }

        let req = req_result.unwrap();

        match self.client.execute(req).await {
            Ok(response) => {
                let status = response.status();
                if status.is_success() {
                    let body = response.json::<TResponse>().await;
                    match body {
                        Ok(val) => Ok(val),
                        Err(err) => Err(ClientError::DeserializationError(err.to_string())),
                    }
                } else {
                    let error_body = response.text().await;
                    match error_body {
                        Ok(body) => Err(ClientError::ServerError(status.as_u16(), body)),
                        Err(err) => Err(ClientError::NetworkError(err.to_string())),
                    }
                }
            }
            Err(err) => Err(ClientError::NetworkError(err.to_string())),
        }
    }
}

impl Default for NomadClient {
    fn default() -> Self {
        NomadClient {
            config: Config::from_env(),
            client: Client::new(),
        }
    }
}

#[derive(Clone, Debug)]
pub struct Config {
    pub base_url: String,
    pub port: u16,
    pub api_version: String,
}

impl Config {
    pub fn from_env() -> Config {
        let mut config = Config::default();

        if let Ok(var) = env::var(ENV_NOMAD_BASE) {
            config.base_url = var
        }

        if let Ok(var) = env::var(ENV_NOMAD_PORT) {
            if let Ok(port) = var.parse::<u16>() {
                config.port = port
            }
        }

        if let Ok(var) = env::var(ENV_NOMAD_API_VERSION) {
            config.api_version = var
        }

        config
    }
}

impl Default for Config {
    fn default() -> Self {
        Config {
            base_url: "http://localhost".into(),
            port: 4646,
            api_version: "v1".into(),
        }
    }
}

#[derive(Error, Debug)]
pub enum ClientError {
    #[error("Error building the request: {0}")]
    RequestError(String),
    #[error("Response could not be deserialized: {0}")]
    DeserializationError(String),
    #[error("The api has returned an error: [{0}] '{0}'")]
    ServerError(u16, String),
    #[error("A network related error occurred: {0}")]
    NetworkError(String),
}