use std::collections::HashMap;
use std::error::Error;
use std::str::FromStr;

use actix_web::{HttpRequest, HttpResponse, web};
use actix_web::http::{HeaderName, HeaderValue};
use serde::Serialize;

use crate::api_data::http_error::HttpError;
use crate::controllers::routes::RequestResult;
use crate::data::api_client::APIClient;
use crate::data::config::conf;
use crate::data::error::{ExecError, ResultBoxError};
use crate::data::user::UserID;
use crate::helpers::{account_helper, api_helper};

/// Http request handler
///
/// @author Pierre Hubert

/// Single request body  value
pub struct RequestValue {
    pub string: Option<String>
}

impl RequestValue {
    /// Build a string value
    pub fn string(s: String) -> RequestValue {
        RequestValue {
            string: Some(s)
        }
    }
}

#[derive(Serialize)]
struct SuccessMessage {
    success: String
}

pub struct HttpRequestHandler {
    request: web::HttpRequest,
    body: HashMap<String, RequestValue>,
    response: Option<web::HttpResponse>,
    headers: HashMap<String, String>,
    client: Option<APIClient>,
    curr_user_id: Option<UserID>,
}

impl HttpRequestHandler {
    /// Construct a new request handler
    pub fn new(req: HttpRequest, body: HashMap<String, RequestValue>) -> HttpRequestHandler {
        HttpRequestHandler {
            request: req,
            body,
            response: None,
            headers: HashMap::new(),
            client: None,
            curr_user_id: None,
        }
    }

    /// Check if a response has been set for this request
    pub fn has_response(&self) -> bool {
        self.response.is_some()
    }

    /// Get the response status code, eg. 200 or 404
    pub fn response_status_code(&self) -> u16 {
        self.response.as_ref().unwrap().status().as_u16()
    }

    /// Take the response from this struct
    pub fn response(self) -> ResultBoxError<HttpResponse> {
        let mut response = self.response.unwrap();

        // Put additional headers if required
        for (k, v) in &self.headers {
            response.headers_mut().insert(HeaderName::from_str(k)?,
                                          HeaderValue::from_str(v)?,
            );
        }

        Ok(response)
    }

    /// Set request response
    pub fn set_response<T: Serialize>(&mut self, data: T) -> RequestResult {
        self.response = Some(HttpResponse::Ok().json(data));
        Ok(())
    }

    /// Success message
    pub fn success(&mut self, message: &str) -> RequestResult {
        self.response = Some(HttpResponse::Ok().json(SuccessMessage {
            success: message.to_string()
        }));
        Ok(())
    }

    /// Internal error response (500)
    pub fn internal_error(&mut self, error: Box<dyn Error>) -> RequestResult {
        self.response = Some(HttpResponse::InternalServerError().json(
            HttpError::internal_error("Internal server error.")));
        Err(error)
    }

    /// Bad request (400)
    pub fn bad_request(&mut self, message: String) -> RequestResult {
        self.response = Some(HttpResponse::BadRequest().json(
            HttpError::bad_request(&message)));
        Err(Box::new(ExecError::new(&message)))
    }

    /// Forbidden (401)
    pub fn forbidden(&mut self, message: String) -> RequestResult {
        self.response = Some(HttpResponse::Forbidden().json(
            HttpError::forbidden(&message)));
        Err(Box::new(ExecError::new(&message)))
    }

    /// If result is not OK, return a bad request
    pub fn ok_or_bad_request<E>(&mut self, res: ResultBoxError<E>, msg: &str) -> ResultBoxError<E> {
        match res {
            Ok(e) => Ok(e),
            Err(err) => {
                println!("Error leading to bad request: {}", err);
                self.bad_request(msg.to_string())?;
                unreachable!()
            }
        }
    }

    /// Get the path of the request
    pub fn request_path(&self) -> String {
        self.request.path().to_string()
    }

    /// Get information about the client which made the request
    pub fn api_client(&self) -> &APIClient {
        self.client.as_ref().unwrap()
    }

    /// Check if a POST parameter was present in the request or not
    pub fn has_post_parameter(&self, name: &str) -> bool {
        self.body.contains_key(name)
    }

    /// Get a post parameter
    pub fn post_parameter(&mut self, name: &str) -> ResultBoxError<&RequestValue> {
        if !self.has_post_parameter(name) {
            self.bad_request(format!("POST parameter '{}' not found in request!", name))?;
        }

        Ok(self.body.get(name).unwrap())
    }

    /// Get a post string
    pub fn post_string(&mut self, name: &str) -> ResultBoxError<String> {
        self.post_string_opt(name, 1, true)
    }

    /// Get a post string, specifying minimum length
    pub fn post_string_opt(&mut self, name: &str, min_length: usize, required: bool)
                           -> ResultBoxError<String> {
        let param = self.post_parameter(name)?;

        match (&param.string, required) {
            (None, true) =>
                Err(self.bad_request(format!("'{}' is not a string!", name)).unwrap_err()),

            (None, false) => Ok(String::new()),

            (Some(s), _) => {
                if s.len() >= min_length {
                    Ok(s.to_string())
                } else {
                    Err(self.bad_request(format!("'{}' is too short!", name)).unwrap_err())
                }
            }
        }
    }

    /// Check API client tokens
    pub fn check_client_token(&mut self) -> RequestResult {
        let api_name = self.post_string("serviceName")?;
        let api_token = self.post_string("serviceToken")?;

        let client = self.ok_or_bad_request(
            api_helper::get_client(&api_name, &api_token),
            "Client not recognized!",
        )?;


        if let Some(domain) = &client.domain {
            let allowed_origin = match conf().force_https {
                true => format!("https://{}", domain),
                false => format!("http://{}", domain)
            };

            match self.request.headers().get("Referer") {
                None => self.bad_request("Unknown origin!".to_string())?,
                Some(s) => {
                    if !s.to_str()?.starts_with(&allowed_origin) {
                        self.bad_request("Use of this client is prohibited from this domain!".to_string())?;
                    }
                }
            }

            self.headers.insert("Access-Control-Allow-Origin".to_string(), allowed_origin);
        }

        self.client = Some(client);

        Ok(())
    }

    /// Check login token
    pub fn check_user_token(&mut self) -> RequestResult {
        let token = self.post_string("userToken1")?;

        // Find user
        match account_helper::get_user_by_login_token(&token, self.api_client()) {
            Ok(id) => {
                self.curr_user_id = Some(id);

                Ok(())
            }
            Err(e) => {
                println!("Error marking login tokens as invalid: {}", e);
                self.response = Some(
                    actix_web::HttpResponse::
                    build(actix_web::http::StatusCode::from_u16(412)?)
                        .json(HttpError::new(412, "Please check your login tokens!")));
                Err(e)
            }
        }
    }

    /// Get user ID. This function assess that a user ID is available to continue
    pub fn user_id(&self) -> ResultBoxError<UserID> {
        match self.curr_user_id {
            Some(s) => Ok(s),
            None => Err(ExecError::boxed_new("Could not get required user ID!"))
        }
    }

    /// Get an email included in the request
    pub fn post_email(&mut self, name: &str) -> ResultBoxError<String> {
        let mail = self.post_string(name)?;

        if !mailchecker::is_valid(&mail) {
            self.bad_request("Invalid email address!".to_string())?;
        }

        Ok(mail)
    }
}