use diesel::prelude::*;
use crate::model::{db_model, schema};
use std::error::Error;
use std::fmt::Debug;
use pbkdf2::password_hash::{PasswordHash, PasswordVerifier};
use pbkdf2::Pbkdf2;
use serde_json::json;

pub async fn add_user(app_state: crate::AppState, username: String, password: String, mail: String) -> Result<(), ()> {
    let conn = app_state
        .db
        .get()
        .await
        .map_err(|_| {
            println!("fail to get db connection");
            ()
        })?;
    let target_username = username.clone();
    // 1. check if current username exists.
    let res = conn.interact(
        move |conn| {
            schema::users::table
                .filter(schema::users::username.eq(target_username.clone()))
                .count()
                .get_result::<i64>(conn)
        })
        .await
        .map_err(|res| {
            ()
        })?
        .map_err(|res| {
            ()
        })?;
    println!("ret {}", res);
    if res > 0 {
        println!("user already exists.");
        return Ok(());
    }
    let new_user_form = db_model::UserForm {
        username: username.clone(),
        password: password.clone(),
        mail: mail.clone(),
    };
    // 2. adding user
    let add_res = conn.interact(
        move |conn| {
            diesel::insert_into(schema::users::table)
                .values(&new_user_form)
                .returning(db_model::User::as_returning())
                .get_result(conn)
        })
        .await
        .map_err(|e| {
            ()
        })?
        .map_err(|e| {
            ()
        })?;
    let out = json!(add_res);
    println!("new user {}", out.to_string());
    Ok(())
}

pub async fn check_user_psw(app_state: crate::AppState, username: String, password: String) -> bool {
    let conn_res = app_state
        .db
        .get()
        .await
        .map_err(|_| {
            println!("fail to get db connection");
            ()
        });
    let conn = match conn_res {
        Ok(res) => res,
        Err(err) => { return false; }
    };
    // 1. get psw hash
    let query_username = username.clone();
    let user_rr = conn.interact(
        |conn| {
            schema::users::table
                .filter(schema::users::username.eq(query_username))
                .select(db_model::User::as_select())
                .get_results(conn)
        })
        .await;

    let user_res = match user_rr {
        Ok(res) => res,
        Err(_) => return false,
    };
    println!("get user_res success");
    let user = match user_res {
        Ok(u) => u,
        Err(_) => return false,
    };

    println!("get user success");

    if user.len() != 1 {
        return false;
    }
    println!("get uniq user success");
    let cur_user = user.get(0);
    let psw = match cur_user {
        Some(usr) => usr.password.clone(),
        None => "".to_string(),
    };
    println!("comparing psw, get {}, stored {}.", password.clone(), psw.clone());

    let hash_res = PasswordHash::new(psw.as_str());
    let hash = match hash_res {
        Ok(rs) => rs,
        Err(_) => return false,
    };
    let check_res = Pbkdf2.verify_password(password.as_bytes(), &hash);
    return check_res.is_ok();
}