use std::sync::LazyLock;

use axum::{
    debug_handler,
    extract::{Path, State},
    response::Response,
};
use phono_backends::{escape_identifier, pg_class::PgClass};
use regex::Regex;
use serde::Deserialize;
use sqlx::{postgres::types::Oid, query};
use uuid::Uuid;
use validator::Validate;

use crate::{
    app::App,
    errors::AppError,
    extractors::ValidatedForm,
    navigator::{Navigator, NavigatorPage as _},
    user::CurrentUser,
    workspace_pooler::WorkspacePooler,
};

static RE_REL_NAME: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"^[a-z][a-z0-9_]*$").unwrap());

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

#[derive(Debug, Deserialize, Validate)]
pub(super) struct FormBody {
    #[validate(regex(path = *RE_REL_NAME))]
    name: String,
}

/// HTTP POST handler for updating a relation's name.
///
/// Currently, names must begin with a letter and may only contain lowercase
/// alphanumeric characters and underscores.
#[debug_handler(state = App)]
pub(super) async fn post(
    State(mut pooler): State<WorkspacePooler>,
    CurrentUser(user): CurrentUser,
    navigator: Navigator,
    Path(PathParams {
        rel_oid,
        workspace_id,
    }): Path<PathParams>,
    ValidatedForm(FormBody { name }): ValidatedForm<FormBody>,
) -> Result<Response, AppError> {
    // FIXME: Check workspace authorization.

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

    let rel = PgClass::with_oid(Oid(rel_oid))
        .fetch_one(&mut workspace_client)
        .await?;
    // FIXME ensure that user has ownership of the table.

    // TODO: move this to a function in `phono_backends`.
    query(&format!(
        "alter table {ident} rename to {name_esc}",
        ident = rel.get_identifier(),
        // `_esc` suffixes to make sure that the macro won't fall back to
        // similarly named variable(s) in scope if anything inadvertently
        // changes.
        name_esc = escape_identifier(&name)
    ))
    .execute(workspace_client.get_conn())
    .await?;

    Ok(navigator
        .rel_page()
        .workspace_id(workspace_id)
        .rel_oid(Oid(rel_oid))
        .suffix("settings/")
        .build()?
        .redirect_to())
}