use std::collections::HashMap;

use rocket::request::{self, Form, FormItems, FromForm, FromRequest, Request};
use rocket::{Outcome, Route};

use rocket_contrib::{Json, Value};

use num_traits::FromPrimitive;

use db::models::*;
use db::DbConn;

use util::{self, JsonMap};

use api::{ApiResult, JsonResult};

pub fn routes() -> Vec<Route> {
    routes![login]
}

#[post("/connect/token", data = "<connect_data>")]
fn login(connect_data: Form<ConnectData>, device_type: DeviceType, conn: DbConn) -> JsonResult {
    let data = connect_data.get();

    match data.grant_type {
        GrantType::RefreshToken => _refresh_login(data, device_type, conn),
        GrantType::Password => _password_login(data, device_type, conn),
    }
}

fn _refresh_login(data: &ConnectData, _device_type: DeviceType, conn: DbConn) -> JsonResult {
    // Extract token
    let token = data.get("refresh_token");

    // Get device by refresh token
    let mut device = match Device::find_by_refresh_token(token, &conn) {
        Some(device) => device,
        None => err!("Invalid refresh token"),
    };

    // COMMON
    let user = User::find_by_uuid(&device.user_uuid, &conn).unwrap();
    let orgs = UserOrganization::find_by_user(&user.uuid, &conn);

    let (access_token, expires_in) = device.refresh_tokens(&user, orgs);
    device.save(&conn);

    Ok(Json(json!({
        "access_token": access_token,
        "expires_in": expires_in,
        "token_type": "Bearer",
        "refresh_token": device.refresh_token,
        "Key": user.key,
        "PrivateKey": user.private_key,
    })))
}

fn _password_login(data: &ConnectData, device_type: DeviceType, conn: DbConn) -> JsonResult {
    // Validate scope
    let scope = data.get("scope");
    if scope != "api offline_access" {
        err!("Scope not supported")
    }

    // Get the user
    let username = data.get("username");
    let user = match User::find_by_mail(username, &conn) {
        Some(user) => user,
        None => err!("Username or password is incorrect. Try again."),
    };

    // Check password
    let password = data.get("password");
    if !user.check_valid_password(password) {
        err!("Username or password is incorrect. Try again.")
    }

    // Let's only use the header and ignore the 'devicetype' parameter
    let device_type_num = device_type.0;

    let (device_id, device_name) = if data.is_device {
        (
            data.get("deviceidentifier").clone(),
            data.get("devicename").clone(),
        )
    } else {
        (format!("web-{}", user.uuid), String::from("web"))
    };

    // Find device or create new
    let mut device = match Device::find_by_uuid(&device_id, &conn) {
        Some(device) => {
            // Check if valid device
            if device.user_uuid != user.uuid {
                device.delete(&conn);
                err!("Device is not owned by user")
            }

            device
        }
        None => {
            // Create new device
            Device::new(device_id, user.uuid.clone(), device_name, device_type_num)
        }
    };

    let twofactor_token = twofactor_auth(&user.uuid, &data, &mut device, &conn)?;

    // Common
    let user = User::find_by_uuid(&device.user_uuid, &conn).unwrap();
    let orgs = UserOrganization::find_by_user(&user.uuid, &conn);

    let (access_token, expires_in) = device.refresh_tokens(&user, orgs);
    device.save(&conn);

    let mut result = json!({
        "access_token": access_token,
        "expires_in": expires_in,
        "token_type": "Bearer",
        "refresh_token": device.refresh_token,
        "Key": user.key,
        "PrivateKey": user.private_key,
        //"TwoFactorToken": "11122233333444555666777888999"
    });

    if let Some(token) = twofactor_token {
        result["TwoFactorToken"] = Value::String(token);
    }

    Ok(Json(result))
}

fn twofactor_auth(
    user_uuid: &str,
    data: &ConnectData,
    device: &mut Device,
    conn: &DbConn,
) -> ApiResult<Option<String>> {
    let twofactors_raw = TwoFactor::find_by_user(user_uuid, conn);
    // Remove u2f challenge twofactors (impl detail)
    let twofactors: Vec<_> = twofactors_raw.iter().filter(|tf| tf.type_ < 1000).collect();

    let providers: Vec<_> = twofactors.iter().map(|tf| tf.type_).collect();

    // No twofactor token if twofactor is disabled
    if twofactors.len() == 0 {
        return Ok(None);
    }

    let provider = match util::parse_option_string(data.get_opt("twoFactorProvider")) {
        Some(provider) => provider,
        None => providers[0], // If we aren't given a two factor provider, asume the first one
    };

    let twofactor_code = match data.get_opt("twoFactorToken") {
        Some(code) => code,
        None => err_json!(_json_err_twofactor(&providers, user_uuid, conn)?),
    };

    let twofactor = twofactors.iter().filter(|tf| tf.type_ == provider).nth(0);

    match TwoFactorType::from_i32(provider) {
        Some(TwoFactorType::Remember) => {
            match &device.twofactor_remember {
                Some(remember) if remember == twofactor_code => return Ok(None), // No twofactor token needed here
                _ => err_json!(_json_err_twofactor(&providers, user_uuid, conn)?),
            }
        }

        Some(TwoFactorType::Authenticator) => {
            let twofactor = match twofactor {
                Some(tf) => tf,
                None => err!("TOTP not enabled"),
            };

            let totp_code: u64 = match twofactor_code.parse() {
                Ok(code) => code,
                _ => err!("Invalid TOTP code"),
            };

            if !twofactor.check_totp_code(totp_code) {
                err_json!(_json_err_twofactor(&providers, user_uuid, conn)?)
            }
        }

        Some(TwoFactorType::U2f) => {
            use api::core::two_factor;

            two_factor::validate_u2f_login(user_uuid, twofactor_code, conn)?;
        }

        _ => err!("Invalid two factor provider"),
    }

    if util::parse_option_string(data.get_opt("twoFactorRemember")).unwrap_or(0) == 1 {
        Ok(Some(device.refresh_twofactor_remember()))
    } else {
        device.delete_twofactor_remember();
        Ok(None)
    }
}

fn _json_err_twofactor(providers: &[i32], user_uuid: &str, conn: &DbConn) -> ApiResult<Value> {
    use api::core::two_factor;

    let mut result = json!({
        "error" : "invalid_grant",
        "error_description" : "Two factor required.",
        "TwoFactorProviders" : providers,
        "TwoFactorProviders2" : {} // { "0" : null }
    });

    for provider in providers {
        result["TwoFactorProviders2"][provider.to_string()] = Value::Null;

        match TwoFactorType::from_i32(*provider) {
            Some(TwoFactorType::Authenticator) => { /* Nothing to do for TOTP */ }

            Some(TwoFactorType::U2f) => {
                let request = two_factor::generate_u2f_login(user_uuid, conn)?;
                let mut challenge_list = Vec::new();

                for key in request.registered_keys {
                    let mut challenge_map = JsonMap::new();

                    challenge_map.insert("appId".into(), Value::String(request.app_id.clone()));
                    challenge_map
                        .insert("challenge".into(), Value::String(request.challenge.clone()));
                    challenge_map.insert("version".into(), Value::String(key.version));
                    challenge_map.insert(
                        "keyHandle".into(),
                        Value::String(key.key_handle.unwrap_or_default()),
                    );

                    challenge_list.push(Value::Object(challenge_map));
                }

                let mut map = JsonMap::new();
                use serde_json;
                let challenge_list_str = serde_json::to_string(&challenge_list).unwrap();

                map.insert("Challenges".into(), Value::String(challenge_list_str));
                result["TwoFactorProviders2"][provider.to_string()] = Value::Object(map);
            }

            _ => {}
        }
    }

    Ok(result)
}

#[derive(Clone, Copy)]
struct DeviceType(i32);

impl<'a, 'r> FromRequest<'a, 'r> for DeviceType {
    type Error = &'static str;

    fn from_request(request: &'a Request<'r>) -> request::Outcome<Self, Self::Error> {
        let headers = request.headers();
        let type_opt = headers.get_one("Device-Type");
        let type_num = util::parse_option_string(type_opt).unwrap_or(0);

        Outcome::Success(DeviceType(type_num))
    }
}

#[derive(Debug)]
struct ConnectData {
    grant_type: GrantType,
    is_device: bool,
    data: HashMap<String, String>,
}

#[derive(Debug, Copy, Clone)]
enum GrantType {
    RefreshToken,
    Password,
}

impl ConnectData {
    fn get(&self, key: &str) -> &String {
        &self.data[&key.to_lowercase()]
    }

    fn get_opt(&self, key: &str) -> Option<&String> {
        self.data.get(&key.to_lowercase())
    }
}

const VALUES_REFRESH: [&str; 1] = ["refresh_token"];
const VALUES_PASSWORD: [&str; 5] = ["client_id", "grant_type", "password", "scope", "username"];
const VALUES_DEVICE: [&str; 3] = ["deviceidentifier", "devicename", "devicetype"];

impl<'f> FromForm<'f> for ConnectData {
    type Error = String;

    fn from_form(items: &mut FormItems<'f>, _strict: bool) -> Result<Self, Self::Error> {
        let mut data = HashMap::new();

        // Insert data into map
        for (key, value) in items {
            match (key.url_decode(), value.url_decode()) {
                (Ok(key), Ok(value)) => data.insert(key.to_lowercase(), value),
                _ => return Err("Error decoding key or value".to_string()),
            };
        }

        // Validate needed values
        let (grant_type, is_device) = match data.get("grant_type").map(String::as_ref) {
            Some("refresh_token") => {
                check_values(&data, &VALUES_REFRESH)?;
                (GrantType::RefreshToken, false) // Device doesn't matter here
            }
            Some("password") => {
                check_values(&data, &VALUES_PASSWORD)?;

                let is_device = match data["client_id"].as_ref() {
                    "browser" | "mobile" => check_values(&data, &VALUES_DEVICE)?,
                    _ => false,
                };
                (GrantType::Password, is_device)
            }
            _ => return Err("Grant type not supported".to_string()),
        };

        Ok(ConnectData {
            grant_type,
            is_device,
            data,
        })
    }
}

fn check_values(map: &HashMap<String, String>, values: &[&str]) -> Result<bool, String> {
    for value in values {
        if !map.contains_key(*value) {
            return Err(format!("{} cannot be blank", value));
        }
    }
    Ok(true)
}