use std::collections::HashMap;

use askama::Template;
use axum::{
    Json,
    extract::{Path, State},
    response::{Html, IntoResponse, Response},
};
use axum_extra::extract::Form;
use interim_models::{
    base::Base,
    field::{Encodable, Field, FieldType, InsertableFieldBuilder, RFC_3339_S},
    lens::{Lens, LensDisplayType},
};
use interim_pgtypes::{escape_identifier, pg_attribute::PgAttribute, pg_class::PgClass};
use serde::Deserialize;
use serde_json::json;
use sqlx::{
    postgres::{PgRow, types::Oid},
    query,
};
use uuid::Uuid;

use crate::{
    app_error::{AppError, bad_request},
    app_state::AppDbConn,
    base_pooler::{BasePooler, RoleAssignment},
    navbar::{NavLocation, Navbar, RelLocation},
    navigator::Navigator,
    settings::Settings,
    user::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::belonging_to_base(base_id)
        .belonging_to_rel(Oid(class_oid))
        .fetch_all(&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): State<Settings>,
    State(mut base_pooler): State<BasePooler>,
    navigator: Navigator,
    AppDbConn(mut app_db): AppDbConn,
    CurrentUser(current_user): CurrentUser,
    Path(LensesPagePath { base_id, class_oid }): Path<LensesPagePath>,
    Form(AddLensPagePostForm { name }): Form<AddLensPagePostForm>,
) -> Result<Response, AppError> {
    // FIXME auth
    // FIXME csrf

    let mut client = base_pooler
        .acquire_for(base_id, RoleAssignment::User(current_user.id))
        .await?;

    let attrs = PgAttribute::all_for_rel(Oid(class_oid))
        .fetch_all(&mut client)
        .await?;

    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?;

    for attr in attrs {
        InsertableFieldBuilder::default_from_attr(&attr)
            .lens_id(lens.id)
            .build()?
            .insert(&mut app_db)
            .await?;
    }

    Ok(navigator.lens_page(&lens).redirect_to())
}

#[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 {
        lens_id,
        base_id,
        class_oid,
    }): Path<LensPagePath>,
) -> Result<Response, AppError> {
    // FIXME auth
    let base = Base::with_id(base_id).fetch_one(&mut app_db).await?;
    let lens = Lens::with_id(lens_id).fetch_one(&mut app_db).await?;

    let mut base_client = base_pooler
        .acquire_for(lens.base_id, RoleAssignment::User(current_user.id))
        .await?;
    let rel = PgClass::with_oid(lens.class_oid)
        .fetch_one(&mut base_client)
        .await?;

    let attrs = PgAttribute::all_for_rel(lens.class_oid)
        .fetch_all(&mut base_client)
        .await?;
    let fields = Field::belonging_to_lens(lens.id)
        .fetch_all(&mut app_db)
        .await?;
    let pkey_attrs = PgAttribute::pkeys_for_rel(lens.class_oid)
        .fetch_all(&mut base_client)
        .await?;

    const FRONTEND_ROW_LIMIT: i64 = 1000;
    let rows: Vec<PgRow> = query(&format!(
        "select {0} from {1}.{2} limit $1",
        pkey_attrs
            .iter()
            .chain(attrs.iter())
            .map(|attr| escape_identifier(&attr.attname))
            .collect::<Vec<_>>()
            .join(", "),
        escape_identifier(&rel.regnamespace),
        escape_identifier(&rel.relname),
    ))
    .bind(FRONTEND_ROW_LIMIT)
    .fetch_all(base_client.get_conn())
    .await?;
    let pkeys: Vec<HashMap<String, Encodable>> = rows
        .iter()
        .map(|row| {
            let mut pkey_values: HashMap<String, Encodable> = HashMap::new();
            for attr in pkey_attrs.clone() {
                let field = Field::default_from_attr(&attr);
                pkey_values.insert(field.name.clone(), field.get_value_encodable(row).unwrap());
            }
            pkey_values
        })
        .collect();

    #[derive(Template)]
    #[template(path = "lens.html")]
    struct ResponseTemplate {
        fields: Vec<Field>,
        all_columns: Vec<PgAttribute>,
        rows: Vec<PgRow>,
        pkeys: Vec<HashMap<String, Encodable>>,
        settings: Settings,
        navbar: Navbar,
    }
    Ok(Html(
        ResponseTemplate {
            all_columns: attrs,
            fields,
            pkeys,
            rows,
            navbar: Navbar::builder()
                .root_path(settings.root_path.clone())
                .base(base.clone())
                .populate_rels(&mut app_db, &mut base_client)
                .await?
                .current(NavLocation::Rel(
                    Oid(class_oid),
                    Some(RelLocation::Lens(lens.id)),
                ))
                .build()?,
            settings,
        }
        .render()?,
    )
    .into_response())
}

#[derive(Debug, Deserialize)]
pub struct AddColumnPageForm {
    name: String,
    label: String,
    field_type: String,
    timestamp_format: Option<String>,
}

fn try_field_type_from_form(form: &AddColumnPageForm) -> Result<FieldType, AppError> {
    let serialized = match form.field_type.as_str() {
        "Timestamp" => {
            json!({
                "t": form.field_type,
                "c": {
                    "format": form.timestamp_format.clone().unwrap_or(RFC_3339_S.to_owned()),
                },
            })
        }
        _ => json!({"t": form.field_type}),
    };
    serde_json::from_value(serialized).or(Err(bad_request!("unable to parse field type")))
}

pub async fn add_column_page_post(
    State(mut base_pooler): State<BasePooler>,
    navigator: Navigator,
    AppDbConn(mut app_db): AppDbConn,
    CurrentUser(current_user): CurrentUser,
    Path(LensPagePath { lens_id, .. }): Path<LensPagePath>,
    Form(form): Form<AddColumnPageForm>,
) -> Result<Response, AppError> {
    // FIXME auth
    // FIXME csrf
    // FIXME validate column name length is less than 64

    let lens = Lens::with_id(lens_id).fetch_one(&mut app_db).await?;
    let base = Base::with_id(lens.base_id).fetch_one(&mut app_db).await?;

    let mut base_client = base_pooler
        .acquire_for(base.id, RoleAssignment::User(current_user.id))
        .await?;

    let class = PgClass::with_oid(lens.class_oid)
        .fetch_one(&mut base_client)
        .await?;

    let field_type = try_field_type_from_form(&form)?;
    let data_type_fragment = field_type.attr_data_type_fragment().ok_or(bad_request!(
        "cannot create column with type specified as Unknown"
    ))?;

    query(&format!(
        r#"
alter table {0}
add column if not exists {1} {2}
"#,
        class.get_identifier(),
        escape_identifier(&form.name),
        data_type_fragment
    ))
    .execute(base_client.get_conn())
    .await?;

    Field::insertable_builder()
        .lens_id(lens.id)
        .name(form.name)
        .label(if form.label.is_empty() {
            None
        } else {
            Some(form.label)
        })
        .field_type(field_type)
        .build()?
        .insert(&mut app_db)
        .await?;

    Ok(navigator.lens_page(&lens).redirect_to())
}

// #[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())
// }

#[derive(Deserialize)]
pub struct UpdateValuePageForm {
    column: String,
    pkeys: HashMap<String, Encodable>,
    value: Encodable,
}

pub async fn update_value_page_post(
    State(mut base_pooler): State<BasePooler>,
    CurrentUser(current_user): CurrentUser,
    Path(LensPagePath {
        base_id, class_oid, ..
    }): Path<LensPagePath>,
    Json(body): Json<UpdateValuePageForm>,
) -> Result<Response, AppError> {
    // FIXME auth
    // FIXME csrf

    let mut base_client = base_pooler
        .acquire_for(base_id, RoleAssignment::User(current_user.id))
        .await?;
    let rel = PgClass::with_oid(Oid(class_oid))
        .fetch_one(&mut base_client)
        .await?;
    let pkey_attrs = PgAttribute::pkeys_for_rel(rel.oid)
        .fetch_all(&mut base_client)
        .await?;

    body.pkeys
        .get(&pkey_attrs.first().unwrap().attname)
        .unwrap()
        .bind_onto(body.value.bind_onto(query(&format!(
            r#"update {0}.{1} set {2} = $1 where {3} = $2"#,
            escape_identifier(&rel.regnamespace),
            escape_identifier(&rel.relname),
            escape_identifier(&body.column),
            escape_identifier(&pkey_attrs.first().unwrap().attname),
        ))))
        .execute(base_client.get_conn())
        .await?;

    Ok(Json(json!({ "ok": true })).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");
}