use std::collections::HashMap;

use askama::Template;
use axum::{
    extract::{Path, State},
    response::{Html, IntoResponse as _, Redirect, Response},
};
use axum_extra::extract::Form;
use interim_models::{
    lens::{Lens, LensDisplayType},
    selection::{AttrFilter, Field, Selection},
};
use interim_pgtypes::pg_attribute::{PgAttribute, fetch_attributes_for_rel};
use serde::Deserialize;
use sqlx::{
    postgres::{PgRow, types::Oid},
    query,
};
use uuid::Uuid;

use crate::{
    app_error::{AppError, not_found},
    app_state::AppDbConn,
    base_pooler::BasePooler,
    bases::Base,
    data_layer::{ToHtmlString as _, Value},
    db_conns::{escape_identifier, init_role},
    settings::Settings,
    users::CurrentUser,
};

#[derive(Deserialize)]
pub struct LensesPagePath {
    base_id: Uuid,
    class_oid: u32,
}

pub async fn lenses_page(
    State(settings): State<Settings>,
    AppDbConn(mut app_db): AppDbConn,
    Path(LensesPagePath { base_id, class_oid }): Path<LensesPagePath>,
) -> Result<Response, AppError> {
    // FIXME auth
    let lenses = Lens::fetch_by_rel(base_id, Oid(class_oid), &mut *app_db).await?;
    #[derive(Template)]
    #[template(path = "lenses.html")]
    struct ResponseTemplate {
        base_id: Uuid,
        class_oid: u32,
        lenses: Vec<Lens>,
        settings: Settings,
    }

    Ok(Html(
        ResponseTemplate {
            base_id,
            class_oid,
            lenses,
            settings,
        }
        .render()?,
    )
    .into_response())
}

pub async fn add_lens_page_get(
    State(settings): State<Settings>,
    AppDbConn(mut app_db): AppDbConn,
    Path(LensesPagePath { base_id, class_oid }): Path<LensesPagePath>,
) -> Result<Response, AppError> {
    // FIXME auth
    #[derive(Template)]
    #[template(path = "add_lens.html")]
    struct ResponseTemplate {
        base_id: Uuid,
        class_oid: u32,
        settings: Settings,
    }

    Ok(Html(
        ResponseTemplate {
            base_id,
            class_oid,
            settings,
        }
        .render()?,
    )
    .into_response())
}

#[derive(Deserialize)]
pub struct AddLensPagePostForm {
    name: String,
}

pub async fn add_lens_page_post(
    State(Settings { root_path, .. }): State<Settings>,
    AppDbConn(mut app_db): AppDbConn,
    Path(LensesPagePath { base_id, class_oid }): Path<LensesPagePath>,
    Form(AddLensPagePostForm { name }): Form<AddLensPagePostForm>,
) -> Result<Response, AppError> {
    // FIXME auth
    // FIXME csrf
    let lens = Lens::insertable_builder()
        .base_id(base_id)
        .class_oid(Oid(class_oid))
        .name(name)
        .display_type(LensDisplayType::Table)
        .build()?
        .insert(&mut *app_db)
        .await?;
    Ok(Redirect::to(&format!(
        "{root_path}/d/{0}/r/{class_oid}/l/{1}",
        base_id.simple(),
        lens.id.simple()
    ))
    .into_response())
}

#[derive(Deserialize)]
pub struct LensPagePath {
    base_id: Uuid,
    class_oid: u32,
    lens_id: Uuid,
}

pub async fn lens_page(
    State(settings): State<Settings>,
    State(mut base_pooler): State<BasePooler>,
    AppDbConn(mut app_db): AppDbConn,
    CurrentUser(current_user): CurrentUser,
    Path(LensPagePath {
        base_id,
        class_oid,
        lens_id,
    }): Path<LensPagePath>,
) -> Result<Response, AppError> {
    // FIXME auth
    let base = Base::fetch_by_id(base_id, &mut *app_db)
        .await?
        .ok_or(AppError::NotFound("no base found with that id".to_owned()))?;
    let mut client = base_pooler.acquire_for(base_id).await?;

    init_role(
        &format!("{}{}", &base.user_role_prefix, &current_user.id.simple()),
        &mut client,
    )
    .await?;

    // FIXME auth

    let class = query!(
        "select relname from pg_class where oid = $1",
        Oid(class_oid)
    )
    .fetch_optional(&mut *client)
    .await?
    .ok_or(AppError::NotFound(
        "no relation found with that oid".to_owned(),
    ))?;

    let lens = Lens::fetch_by_id(lens_id, &mut *app_db)
        .await?
        .ok_or(not_found!("no lens found with that id"))?;

    let attrs = fetch_attributes_for_rel(Oid(class_oid), &mut *client).await?;

    let selections = lens.fetch_selections(&mut *app_db).await?;
    let mut fields: Vec<Field> = Vec::with_capacity(selections.len());
    for selection in selections.clone() {
        fields.append(&mut selection.resolve_fields_from_attrs(&attrs));
    }

    const FRONTEND_ROW_LIMIT: i64 = 1000;
    let rows = query(&format!(
        "select {} from {} limit $1",
        attrs
            .iter()
            .map(|attr| attr.attname.clone())
            .collect::<Vec<_>>()
            .join(", "),
        escape_identifier(&class.relname),
    ))
    .bind(FRONTEND_ROW_LIMIT)
    .fetch_all(&mut *client)
    .await?;
    #[derive(Template)]
    #[template(path = "lens.html")]
    struct ResponseTemplate {
        fields: Vec<Field>,
        all_columns: Vec<PgAttribute>,
        rows: Vec<PgRow>,
        selections_json: String,
        settings: Settings,
    }
    Ok(Html(
        ResponseTemplate {
            all_columns: attrs,
            fields,
            rows,
            selections_json: serde_json::to_string(&selections)?,
            settings,
        }
        .render()?,
    )
    .into_response())
}

#[derive(Debug, Deserialize)]
pub struct AddSelectionPageForm {
    column: String,
}

pub async fn add_selection_page_post(
    State(settings): State<Settings>,
    AppDbConn(mut app_db): AppDbConn,
    CurrentUser(current_user): CurrentUser,
    Path(LensPagePath {
        base_id,
        class_oid,
        lens_id,
    }): Path<LensPagePath>,
    Form(form): Form<AddSelectionPageForm>,
) -> Result<Response, AppError> {
    dbg!(&form);
    // FIXME auth
    // FIXME csrf

    let lens = Lens::fetch_by_id(lens_id, &mut *app_db)
        .await?
        .ok_or(not_found!("lens not found"))?;
    Selection::insertable_builder()
        .lens_id(lens.id)
        .attr_filters(vec![AttrFilter::NameEq(form.column)])
        .build()?
        .insert(&mut *app_db)
        .await?;

    Ok(Redirect::to(&format!(
        "{0}/d/{base_id}/r/{class_oid}/l/{lens_id}/",
        settings.root_path
    ))
    .into_response())
}

pub async fn update_lens_page_post(
    State(settings): State<Settings>,
    AppDbConn(mut app_db): AppDbConn,
    CurrentUser(current_user): CurrentUser,
    Path(LensPagePath {
        base_id,
        class_oid,
        lens_id,
    }): Path<LensPagePath>,
    Form(form): Form<HashMap<String, String>>,
) -> Result<Response, AppError> {
    dbg!(&form);
    // FIXME auth
    // FIXME csrf

    Ok(Redirect::to(&format!(
        "{0}/d/{base_id}/r/{class_oid}/l/{lens_id}/",
        settings.root_path
    ))
    .into_response())
}

#[derive(Deserialize)]
pub struct ViewerPagePath {
    base_id: Uuid,
    class_oid: u32,
    lens_id: Uuid,
}

pub async fn viewer_page(
    State(settings): State<Settings>,
    State(mut base_pooler): State<BasePooler>,
    AppDbConn(mut app_db): AppDbConn,
    CurrentUser(current_user): CurrentUser,
    Path(params): Path<ViewerPagePath>,
) -> Result<Response, AppError> {
    todo!("not yet implemented");
}