use std::ops::{Deref, DerefMut};
use axum::extract::{FromRequest, FromRequestParts, Request};
use axum::http::StatusCode;
use axum::{async_trait, RequestPartsExt};
use axum::extract::rejection::FormRejection;
use axum::response::{IntoResponse, IntoResponseParts};
use crate::app::routes::AppState;
use crate::error::AppError;
use super::htmx_form_data::{HtmxFormData, HtmxFormDataError};

#[derive(Debug, Clone, Copy, Default)]
pub struct ValidatedForm<T>(pub T);

#[async_trait]
impl<T> FromRequest<AppState> for ValidatedForm<T>
where
    T: HtmxFormData
{
    type Rejection = ValidatedFormError<T::FormTemplate>;

    async fn from_request(req: Request, state: &AppState) -> Result<Self, Self::Rejection> {

        let raw_form_data = axum::Form::<T>::from_request(req, state)
            .await
            .map_err(|e| ValidatedFormError::FormError(e))?;

        let value = raw_form_data.0
            .validate(&state)
            .await
            .map_err(|e|
                match e {
                    HtmxFormDataError::ValidationError(e) => ValidatedFormError::ValidationError(e),
                    HtmxFormDataError::InternalServerError(e) => ValidatedFormError::InternalServerError(e),
                }
            )?;

        Ok(ValidatedForm(value))
    }
}

impl<T> Deref for ValidatedForm<T> {
    type Target = T;

    #[inline]
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl<T> DerefMut for ValidatedForm<T> {
    #[inline]
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.0
    }
}

pub enum ValidatedFormError<T> {
    ValidationError(T),
    FormError(FormRejection),
    InternalServerError(anyhow::Error)
}


impl<T> IntoResponse for ValidatedFormError<T>
where T: IntoResponse
{
    fn into_response(self) -> axum::response::Response {
        match self {
            ValidatedFormError::FormError(err) => {
                err.into_response()
            },
            ValidatedFormError::ValidationError(err) => {
                let (mut parts, body) = err.into_response().into_parts();
                parts.status = StatusCode::OK;
                (parts, body).into_response()
            }
            ValidatedFormError::InternalServerError(err) => {
                AppError::from(err).into_response()
            }
        }
    }
}