use actix_web::{web, HttpResponse, Responder};
use serde::Deserialize;
use sqlx::PgPool;

use crate::{
    endpoints::vehicle_assignment::PlanVehiclesPartialTemplate,
    utils::{
        event_planning_template::generate_vehicles_assigned_and_available, ApplicationError,
        TemplateResponse,
    },
};
use brass_db::models::{Event, Role, User, Vehicle, VehicleAssignment};

#[derive(Deserialize)]
pub struct VehicleAssignmentQuery {
    event: i32,
}

#[derive(Deserialize)]
pub struct VehicleAssignmentForm {
    vehicle: i32,
}

#[actix_web::post("/vehicleassignments/new")]
pub async fn post(
    user: web::ReqData<User>,
    pool: web::Data<PgPool>,
    form: web::Form<VehicleAssignmentForm>,
    query: web::Query<VehicleAssignmentQuery>,
) -> Result<impl Responder, ApplicationError> {
    let Some(event) = Event::read_by_id_including_location(pool.get_ref(), query.event).await?
    else {
        return Ok(HttpResponse::NotFound().finish());
    };

    let user_is_admin_or_area_manager_of_event_area = user.role == Role::Admin
        || (user.role == Role::AreaManager
            && user.area_id == event.location.as_ref().unwrap().area_id);

    if !user_is_admin_or_area_manager_of_event_area {
        return Err(ApplicationError::Unauthorized);
    }

    let Some(vehicle) = Vehicle::read(pool.get_ref(), form.vehicle).await? else {
        return Ok(HttpResponse::NotFound().finish());
    };

    let existing_assignments_for_vehicle = VehicleAssignment::read_all_by_vehicle_and_date(
        pool.get_ref(),
        vehicle.id,
        event.start.date(),
    )
    .await?;
    let has_start_time_during_event =
        |a: &VehicleAssignment| a.start >= event.start && a.start <= event.end;
    let has_end_time_during_event =
        |a: &VehicleAssignment| a.end >= event.start && a.end <= event.end;

    let availability_already_assigned = existing_assignments_for_vehicle
        .iter()
        .any(|a| has_start_time_during_event(a) || has_end_time_during_event(a));

    if availability_already_assigned {
        return Ok(HttpResponse::BadRequest()
            .body("Vehicle already assigned to a timely conflicting event."));
    }

    VehicleAssignment::create(pool.get_ref(), event.id, vehicle.id, event.start, event.end).await?;

    let (vehicles_assigned, vehicles_available) =
        generate_vehicles_assigned_and_available(pool.get_ref(), &event).await?;
    let template = PlanVehiclesPartialTemplate {
        event,
        vehicles_assigned,
        vehicles_available,
    };

    Ok(template.to_response()?)
}