use axum::{
    extract::{Form, Path, Query, State},
    http::StatusCode,
    response::{IntoResponse, Redirect, Response},
};
use http::HeaderValue;
use julid::Julid;
use serde::Deserialize;
use sqlx::{query, query_as, query_scalar, SqlitePool};

use super::templates::{AddNewWatchPage, AddWatchButton, GetWatchPage, SearchWatchesPage};
use crate::{
    misc_util::{empty_string_as_none, year_to_epoch},
    AuthSession, MyWatchesPage, ShowKind, Watch, WatchQuest,
};

//-************************************************************************
// Constants
//-************************************************************************

const GET_SAVED_WATCHES_QUERY: &str = "select * from watches inner join watch_quests quests on quests.user = $1 and quests.watch = watches.id";
const GET_QUEST_QUERY: &str = "select * from watch_quests where user = ? and watch = ?";

const GET_WATCH_QUERY: &str = "select * from watches where id = $1";

const DEFAULT_WATCHES_QUERY: &str =
    "select * from (select * from watches order by random() limit 50) order by release_date asc";

const ADD_WATCH_QUERY: &str = "insert into watches (title, kind, release_date, metadata_url, added_by, length) values ($1, $2, $3, $4, $5, $6) returning id";
const ADD_WATCH_QUEST_QUERY: &str =
    "insert into watch_quests (user, watch, public, watched) values ($1, $2, $3, $4)";

const CHECKMARK: &str = "✓";

//-************************************************************************
// Error types for Watch creation
//-************************************************************************

#[Error]
pub struct AddError(#[from] AddErrorKind);

#[Error]
#[non_exhaustive]
pub enum AddErrorKind {
    UnknownDBError,
    NotSignedIn,
}

impl IntoResponse for AddError {
    fn into_response(self) -> Response {
        match &self.0 {
            AddErrorKind::UnknownDBError => {
                (StatusCode::INTERNAL_SERVER_ERROR, format!("{self}")).into_response()
            }
            AddErrorKind::NotSignedIn => (
                StatusCode::OK,
                "Ope, you need to sign in first!".to_string(),
            )
                .into_response(),
        }
    }
}

//-************************************************************************
// Types for receiving arguments from forms
//-************************************************************************

#[derive(Debug, Default, Clone, Deserialize, PartialEq, Eq)]
pub struct SearchQuery {
    #[serde(default, deserialize_with = "empty_string_as_none")]
    pub search: Option<String>,
    #[serde(default, deserialize_with = "empty_string_as_none")]
    pub title: Option<String>,
    #[serde(default, deserialize_with = "empty_string_as_none")]
    pub kind: Option<String>,
    #[serde(default, deserialize_with = "empty_string_as_none")]
    pub year: Option<i64>,
}

// kinda the main form?
#[derive(Debug, Default, Deserialize, PartialEq, Eq)]
pub struct PostAddNewWatch {
    pub title: String,
    #[serde(default)]
    pub private: bool,
    pub kind: ShowKind,
    #[serde(default, deserialize_with = "empty_string_as_none")]
    pub year: Option<String>, // need a date-picker or something
    #[serde(default, deserialize_with = "empty_string_as_none")]
    pub metadata_url: Option<String>,
    #[serde(default)]
    pub watched_already: bool,
}

#[derive(Debug, Default, Deserialize, PartialEq, Eq)]
pub struct PostAddExistingWatch {
    pub watch: String,
    pub public: bool,
}

//-************************************************************************
// handlers
//-************************************************************************

pub async fn get_add_new_watch(auth: AuthSession) -> impl IntoResponse {
    AddNewWatchPage { user: auth.user }
}

/// Add a Watch to your watchlist (side effects system-add)
pub async fn post_add_new_watch(
    auth: AuthSession,
    State(pool): State<SqlitePool>,
    Form(form): Form<PostAddNewWatch>,
) -> Result<impl IntoResponse, AddError> {
    if let Some(user) = auth.user {
        {
            let release_date = year_to_epoch(form.year.as_deref());
            let watch = Watch {
                title: form.title,
                kind: form.kind,
                metadata_url: form.metadata_url,
                release_date,
                added_by: user.id,
                ..Default::default()
            };

            let watch_id = add_new_watch_impl(&pool, &watch).await?;
            let quest = WatchQuest {
                user: user.id,
                public: !form.private,
                watched: false,
                watch: watch_id,
            };
            add_watch_quest_impl(&pool, &quest)
                .await
                .map_err(|_| AddErrorKind::UnknownDBError)?;

            let location = format!("/watch/{watch_id}");
            Ok(Redirect::to(&location))
        }
    } else {
        Err(AddErrorKind::NotSignedIn.into())
    }
}

async fn add_new_watch_impl(db_pool: &SqlitePool, watch: &Watch) -> Result<Julid, AddError> {
    let watch_id: Julid = query_scalar(ADD_WATCH_QUERY)
        .bind(&watch.title)
        .bind(watch.kind)
        .bind(watch.release_date)
        .bind(&watch.metadata_url)
        .bind(watch.added_by)
        .bind(watch.length)
        .fetch_one(db_pool)
        .await
        .map_err(|err| {
            tracing::error!("Got error: {err}");
            AddErrorKind::UnknownDBError
        })?;
    Ok(watch_id)
}

/// Add a Watch to your watchlist by selecting it with a checkbox
pub async fn post_add_watch_quest(
    auth: AuthSession,
    State(pool): State<SqlitePool>,
    Form(form): Form<PostAddExistingWatch>,
) -> Result<impl IntoResponse, AddError> {
    if let Some(user) = auth.user {
        let quest = WatchQuest {
            user: user.id,
            watch: Julid::from_str(&form.watch).unwrap(),
            public: form.public,
            watched: false,
        };
        add_watch_quest_impl(&pool, &quest)
            .await
            .map_err(|_| AddErrorKind::UnknownDBError)?;
        let resp = checkmark(form.public);
        Ok(resp.into_response())
    } else {
        let resp = Redirect::to("/login");
        let mut resp = resp.into_response();
        resp.headers_mut()
            .insert("HX-Redirect", HeaderValue::from_str("/login").unwrap());
        Ok(resp)
    }
}

pub async fn add_watch_quest_impl(pool: &SqlitePool, quest: &WatchQuest) -> Result<(), ()> {
    query(ADD_WATCH_QUEST_QUERY)
        .bind(quest.user)
        .bind(quest.watch)
        .bind(quest.public)
        .bind(quest.watched)
        .execute(pool)
        .await
        .map_err(|err| {
            tracing::error!("Got error: {err}");
        })?;
    Ok(())
}

/// A single Watch
pub async fn get_watch(
    auth: AuthSession,
    watch: Option<Path<String>>,
    State(pool): State<SqlitePool>,
) -> impl IntoResponse {
    let id = if let Some(Path(id)) = watch {
        id
    } else {
        "".to_string()
    };
    let id = id.trim();
    let id = Julid::from_str(id).unwrap_or_default();
    let q = query_as(GET_WATCH_QUERY).bind(id);
    let watch: Option<Watch> = q.fetch_one(&pool).await.ok();

    GetWatchPage {
        watch,
        user: auth.user,
    }
}

/// everything the user has saved
pub async fn get_watches(auth: AuthSession, State(pool): State<SqlitePool>) -> impl IntoResponse {
    let user = auth.user;
    let watches: Vec<Watch> = if (user).is_some() {
        query_as(GET_SAVED_WATCHES_QUERY)
            .bind(user.as_ref().unwrap().id)
            .fetch_all(&pool)
            .await
            .unwrap_or_default()
    } else {
        vec![]
    };

    MyWatchesPage { watches, user }
}

pub async fn get_search_watch(
    auth: AuthSession,
    State(pool): State<SqlitePool>,
    search: Query<SearchQuery>,
) -> impl IntoResponse {
    let user = auth.user;
    let search_query = search.0;

    let query = if search_query == SearchQuery::default() {
        query_as(DEFAULT_WATCHES_QUERY)
    } else if let Some(title) = search_query.title {
        query_as(
            "select * from watches where id in (select id from watch_search where title match ? order by rank)",
        )
        .bind(title)
    } else if let Some(ref search) = search_query.search {
        query_as("select * from watches where id in (select id from watch_search where title match ?) outer join (select * from stars where id in (select id from star_search where name match ?)) s")
            .bind(search).bind(search)
    } else {
        query_as(DEFAULT_WATCHES_QUERY)
    };

    // until tantivy search
    let watches: Vec<Watch> = query.fetch_all(&pool).await.unwrap();

    SearchWatchesPage { watches, user }
}

pub async fn get_watch_status(
    auth: AuthSession,
    State(pool): State<SqlitePool>,
    Path(watch): Path<String>,
) -> Result<impl IntoResponse, ()> {
    if let Some(user) = auth.user {
        let watch = Julid::from_str(&watch).unwrap();
        let quest: Option<WatchQuest> = query_as(GET_QUEST_QUERY)
            .bind(user.id)
            .bind(watch)
            .fetch_optional(&pool)
            .await
            .map_err(|e| {
                tracing::error!("Got error from checking watch status: {e:?}");
            })?;
        match quest {
            Some(quest) if quest.watched => Ok(format!("{CHECKMARK} watched").into_response()),
            Some(quest) => Ok(checkmark(quest.public).into_response()),
            None => Ok(AddWatchButton { watch }.into_response()),
        }
    } else {
        Ok("<a href='/login'>Login to add</a>".into_response())
    }
}

fn checkmark(public: bool) -> String {
    let public = if public { "public" } else { "private" };
    format!("{CHECKMARK} ({public})")
}