use axum::{
    debug_handler,
    extract::{Path, State},
    response::Response,
};
// [`axum_extra`]'s form extractor is preferred:
// https://docs.rs/axum-extra/0.10.1/axum_extra/extract/struct.Form.html#differences-from-axumextractform
use axum_extra::extract::Form;
use phono_backends::{escape_identifier, pg_class::PgClass};
use phono_models::{
    accessors::{Accessor as _, Actor, portal::PortalAccessor},
    field::Field,
    presentation::Presentation,
};
use serde::Deserialize;
use sqlx::{postgres::types::Oid, query};
use uuid::Uuid;

use crate::{
    app::{App, AppDbConn},
    errors::AppError,
    navigator::{Navigator, NavigatorPage},
    presentation_form::PresentationForm,
    roles::get_writer_role,
    user::CurrentUser,
    workspace_pooler::{RoleAssignment, WorkspacePooler},
};

#[derive(Debug, Deserialize)]
pub(super) struct PathParams {
    portal_id: Uuid,
    rel_oid: u32,
    workspace_id: Uuid,
}

// FIXME: validate name, prevent leading underscore
#[derive(Debug, Deserialize)]
pub(super) struct FormBody {
    name: String,
    table_label: String,

    #[serde(flatten)]
    presentation_form: PresentationForm,
}

/// HTTP POST handler for adding a [`Field`] to a [`Portal`]. If the field name
/// does not match a column in the backing database, a new column is created
/// with a compatible type.
///
/// This handler expects 3 path parameters with the structure described by
/// [`PathParams`].
#[debug_handler(state = App)]
pub(super) async fn post(
    State(mut pooler): State<WorkspacePooler>,
    AppDbConn(mut app_db): AppDbConn,
    CurrentUser(user): CurrentUser,
    navigator: Navigator,
    Path(PathParams {
        portal_id,
        rel_oid,
        workspace_id,
    }): Path<PathParams>,
    Form(form): Form<FormBody>,
) -> Result<Response, AppError> {
    // FIXME: csrf

    let mut workspace_client = pooler
        .acquire_for(workspace_id, RoleAssignment::User(user.id))
        .await?;

    let rel = PgClass::with_oid(Oid(rel_oid))
        .fetch_one(&mut workspace_client)
        .await?;

    let portal = PortalAccessor::new()
        .id(portal_id)
        .as_actor(Actor::User(user.id))
        .verify_workspace_id(workspace_id)
        .verify_rel_oid(Oid(rel_oid))
        .verify_rel_ownership()
        .using_rel(&rel)
        .using_app_db(&mut app_db)
        .using_workspace_client(&mut workspace_client)
        .fetch_one()
        .await?;

    let presentation = Presentation::try_from(form.presentation_form)?;

    query(&format!(
        "alter table {ident} add column if not exists {col} {typ}",
        ident = rel.get_identifier(),
        col = escape_identifier(&form.name),
        typ = presentation.attr_data_type_fragment(),
    ))
    .execute(workspace_client.get_conn())
    .await?;
    query(&format!(
        "grant insert ({col}), update ({col}) on table {ident} to {writer_role}",
        col = escape_identifier(&form.name),
        ident = rel.get_identifier(),
        writer_role = escape_identifier(&get_writer_role(&rel)?),
    ))
    .execute(workspace_client.get_conn())
    .await?;

    Field::insert()
        .portal_id(portal.id)
        .name(form.name)
        .table_label(if form.table_label.is_empty() {
            None
        } else {
            Some(form.table_label)
        })
        .presentation(presentation)
        .build()?
        .insert(&mut app_db)
        .await?;

    Ok(navigator
        .portal_page()
        .workspace_id(workspace_id)
        .rel_oid(Oid(rel_oid))
        .portal_id(portal_id)
        .build()?
        .redirect_to())
}