use std::{net::Ipv6Addr, sync::Arc};

use axum::{
    extract::{Query, State},
    http::StatusCode,
    response::IntoResponse,
    routing::{get, post},
    Form, Json, Router,
};
use secrecy::ExposeSecret;
use serde::{Deserialize, Serialize};
use tracing::{event, instrument, Level};

use crate::auth::{
    AuthenticationError, ServerPadlockGenerator, UserAuthenticator, UserServerKeyGenerator,
};
use crate::secrets::{Password, ServerHash, UserToken};

#[derive(Debug, Clone)]
struct AppState {
    user_authenticator: Arc<UserAuthenticator>,
    server_padlock_generator: Arc<ServerPadlockGenerator>,
    user_server_key_generator: Arc<UserServerKeyGenerator>,
}

#[instrument]
pub async fn run(
    port: u16,
    user_authenticator: Arc<UserAuthenticator>,
    server_padlock_generator: Arc<ServerPadlockGenerator>,
    user_server_key_generator: Arc<UserServerKeyGenerator>,
) -> color_eyre::Result<()> {
    let app_state = AppState {
        user_authenticator,
        server_padlock_generator,
        user_server_key_generator,
    };

    let app = Router::new()
        .route("/tls-check/success", get(|| async { "OK" }))
        .route("/api-login", post(api_login))
        .route(
            "/generate-user-server-key-2",
            post(generate_user_server_key_2),
        )
        .route(
            "/generate-server-padlock-2",
            post(generate_server_padlock_2),
        )
        .with_state(app_state);

    let listener = tokio::net::TcpListener::bind((Ipv6Addr::UNSPECIFIED, port)).await?;
    axum::serve(listener, app).await?;

    Ok(())
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
struct ApiError {
    #[serde(skip_serializing)]
    status: StatusCode,
    error: String,
    message: String,
}

impl From<AuthenticationError> for ApiError {
    fn from(err: AuthenticationError) -> Self {
        Self {
            status: StatusCode::UNAUTHORIZED,
            error: "authentication-failed".to_owned(),
            message: err.to_string(),
        }
    }
}

impl IntoResponse for ApiError {
    fn into_response(self) -> axum::response::Response {
        (self.status, Json(self)).into_response()
    }
}

type ApiResult<T> = Result<T, ApiError>;

fn default_api_version() -> String {
    "4".to_owned()
}

#[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
struct ApiVersion {
    #[serde(default = "default_api_version")]
    api_version: String,
}

#[derive(Debug, Clone, Deserialize)]
struct LoginRequest {
    username: String,
    password: Password,
}

#[derive(Debug, Clone, Serialize)]
struct LoginResponse {
    username: String,
    token: String,
}

#[instrument]
async fn api_login(
    State(AppState {
        user_authenticator, ..
    }): State<AppState>,
    Query(ApiVersion { api_version }): Query<ApiVersion>,
    Form(LoginRequest { username, password }): Form<LoginRequest>,
) -> ApiResult<Json<LoginResponse>> {
    event!(Level::INFO, "Generating user key");

    let (username, user_token) = user_authenticator
        .get_user_token(&username, &password)
        .await?;

    Ok(Json(LoginResponse {
        username,
        token: user_token.0.expose_secret().to_owned(),
    }))
}

#[derive(Debug, Clone, Deserialize)]
struct UserServerKeyRequest {
    username: String,
    token: UserToken,
    server_hash: ServerHash,
}

#[derive(Debug, Clone, Serialize)]
struct UserServerKeyResponse {
    server_key: String,
    server_key_timestamp: String,
}

#[instrument]
async fn generate_user_server_key_2(
    State(AppState {
        user_server_key_generator,
        ..
    }): State<AppState>,
    Query(ApiVersion { api_version }): Query<ApiVersion>,
    Form(UserServerKeyRequest {
        username,
        token,
        server_hash,
    }): Form<UserServerKeyRequest>,
) -> ApiResult<Json<UserServerKeyResponse>> {
    event!(Level::INFO, "Creating user_server_key");

    let (server_key, server_key_timestamp) = user_server_key_generator
        .generate_user_server_key(&username, &token, &server_hash)
        .await?;

    Ok(Json(UserServerKeyResponse {
        server_key: server_key.0.expose_secret().to_owned(),
        server_key_timestamp,
    }))
}

#[derive(Serialize)]
struct ServerPadlockResponse {
    server_hash: ServerHash,
    server_padlock: String,
}

#[instrument]
async fn generate_server_padlock_2(
    State(AppState {
        server_padlock_generator,
        ..
    }): State<AppState>,
    Query(ApiVersion { api_version }): Query<ApiVersion>,
) -> ApiResult<Json<ServerPadlockResponse>> {
    event!(Level::INFO, "Creating server padlock");

    let server_hash = ServerPadlockGenerator::generate_hash();
    let server_padlock = server_padlock_generator.generate_padlock(&server_hash);

    Ok(Json(ServerPadlockResponse {
        server_hash,
        server_padlock: server_padlock.0.expose_secret().to_owned(),
    }))
}