use std::ops::DerefMut;

use super::{
    role::Role,
    user::{ManageUserUser, User},
};
use chrono::{DateTime, Duration, Local, NaiveDateTime, TimeZone, Utc};
use serde::{Deserialize, Serialize};
use sqlx::{FromRow, Sqlite, SqlitePool, Transaction};

#[derive(FromRow, Debug, Serialize, Deserialize, Clone)]
pub struct Activity {
    pub id: i64,
    pub created_at: NaiveDateTime,
    pub text: String,
    pub relevant_for: String,
    pub keep_until: Option<NaiveDateTime>,
}

#[derive(Serialize, Deserialize, Debug)]
pub struct ActivityWithDetails {
    #[serde(flatten)]
    pub(crate) activity: Activity,
    keep_until_days: Option<i64>,
}

impl From<Activity> for ActivityWithDetails {
    fn from(activity: Activity) -> Self {
        let keep_until_days = activity.keep_until.map(|keep_until| {
            let now = Utc::now().naive_utc();
            let duration = keep_until.signed_duration_since(now);
            duration.num_days()
        });

        Self {
            keep_until_days,
            activity,
        }
    }
}

// TODO: add `reason` as additional db field, to be able to query and show this to the users
pub enum Reason<'a> {
    Auth(ReasonAuth<'a>),
    // `User` changed the data of `User`, explanation in `String`
    UserDataChange(&'a ManageUserUser, &'a User, String),
    // New Note for User
    NewUserNote(&'a ManageUserUser, &'a User, String),
}

impl From<Reason<'_>> for ActivityBuilder {
    fn from(value: Reason<'_>) -> Self {
        match value {
            Reason::Auth(auth) => auth.into(),
            Reason::UserDataChange(changed_by, changed_user, explanation) => Self::new(&format!(
                "{changed_by} hat die Daten von {changed_user} aktualisiert: {explanation}"
            ))
            .relevant_for_user(changed_user),
            Reason::NewUserNote(changed_by, user, explanation) => {
                Self::new(&format!("({changed_by}) {explanation}")).relevant_for_user(user)
            }
        }
    }
}

pub enum ReasonAuth<'a> {
    // `User` tried to login with `String` as UserAgent
    SuccLogin(&'a User, String),
    // `User` tried to login which was already deleted
    DeletedUserLogin(&'a User),
    // `User` tried to login, supplied wrong PW
    WrongPw(&'a User),
}

impl<'a> From<ReasonAuth<'a>> for Reason<'a> {
    fn from(auth_reason: ReasonAuth<'a>) -> Self {
        Reason::Auth(auth_reason)
    }
}

impl From<ReasonAuth<'_>> for ActivityBuilder {
    fn from(value: ReasonAuth<'_>) -> Self {
        match value {
            ReasonAuth::SuccLogin(user, agent) => {
                Self::new(&format!("{user} hat sich eingeloggt (User-Agent: {agent})"))
                    .relevant_for_user(user)
                    .keep_until_days(7)
            }
            ReasonAuth::DeletedUserLogin(user) => Self::new(&format!(
                "User {user} wollte sich einloggen, klappte jedoch nicht weil er gelöscht wurde."
            ))
            .relevant_for_user(user)
            .keep_until_days(30),
            ReasonAuth::WrongPw(user) => Self::new(&format!(
                "User {user} wollte sich einloggen, hat jedoch das falsche Passwort angegeben."
            ))
            .relevant_for_user(user)
            .keep_until_days(7),
        }
    }
}

pub struct ActivityBuilder {
    text: String,
    relevant_for: String,
    keep_until: Option<NaiveDateTime>,
}

impl ActivityBuilder {
    /// TODO: maybe make this private, and only allow specific acitivites defined in `Reason`
    #[must_use]
    pub fn new(text: &str) -> Self {
        Self {
            text: text.into(),
            relevant_for: String::new(),
            keep_until: None,
        }
    }

    #[must_use]
    pub fn relevant_for_user(self, user: &User) -> Self {
        Self {
            relevant_for: format!("{}user-{};", self.relevant_for, user.id),
            ..self
        }
    }

    #[must_use]
    pub fn relevant_for_role(self, role: &Role) -> Self {
        Self {
            relevant_for: format!("{}role-{};", self.relevant_for, role.id),
            ..self
        }
    }

    #[must_use]
    pub fn keep_until_days(self, days: i64) -> Self {
        let now = Utc::now().naive_utc();
        Self {
            keep_until: Some(now + Duration::days(days)),
            ..self
        }
    }

    pub async fn save(self, db: &SqlitePool) {
        Activity::create(db, &self.text, &self.relevant_for, self.keep_until).await;
    }

    pub async fn save_tx(self, db: &mut Transaction<'_, Sqlite>) {
        Activity::create_with_tx(db, &self.text, &self.relevant_for, self.keep_until).await;
    }
}

impl Activity {
    pub async fn find_by_id(db: &SqlitePool, id: i64) -> Option<Self> {
        sqlx::query_as!(
            Self,
            "SELECT id, created_at, text, relevant_for, keep_until FROM activity WHERE id like ?",
            id
        )
        .fetch_one(db)
        .await
        .ok()
    }
    pub(super) async fn create_with_tx(
        db: &mut Transaction<'_, Sqlite>,
        text: &str,
        relevant_for: &str,
        keep_until: Option<NaiveDateTime>,
    ) {
        sqlx::query!(
            "INSERT INTO activity(text, relevant_for, keep_until) VALUES (?, ?, ?)",
            text,
            relevant_for,
            keep_until
        )
        .execute(db.deref_mut())
        .await
        .unwrap();
    }

    pub(super) async fn create(
        db: &SqlitePool,
        text: &str,
        relevant_for: &str,
        keep_until: Option<NaiveDateTime>,
    ) {
        let mut tx = db.begin().await.unwrap();
        Self::create_with_tx(&mut tx, text, relevant_for, keep_until).await;
        tx.commit().await.unwrap();
    }

    pub async fn for_user(db: &SqlitePool, user: &User) -> Vec<Activity> {
        let user_str = format!("user-{};", user.id);
        sqlx::query_as!(
            Self,
            "
SELECT id, created_at, text, relevant_for, keep_until FROM activity
WHERE 
  relevant_for like CONCAT('%', ?, '%')
ORDER BY created_at DESC;
            ",
            user_str
        )
        .fetch_all(db)
        .await
        .unwrap()
    }

    async fn last(db: &SqlitePool) -> Vec<Self> {
        sqlx::query_as!(
            Self,
            "
SELECT id, created_at, text, relevant_for, keep_until FROM activity 
ORDER BY id DESC
LIMIT 1000
    "
        )
        .fetch_all(db)
        .await
        .unwrap()
    }

    pub async fn show(db: &SqlitePool) -> String {
        let mut ret = String::new();

        for log in Self::last(db).await {
            let utc_time: DateTime<Utc> = Utc::from_utc_datetime(&Utc, &log.created_at);
            let local_time = utc_time.with_timezone(&Local);
            ret.push_str(&format!("- {local_time}: {}\n", log.text));
        }

        ret
    }
}