use actix_web::{http::header::LOCATION, web, HttpResponse, Responder};
use chrono::{NaiveDate, NaiveTime};
use garde::Validate;
use serde::Deserialize;
use sqlx::PgPool;

use crate::{
    endpoints::IdPath,
    models::{
        Assignment, AssignmentChangeset, Availabillity, Event, EventChangeset, EventContext,
        Function, Location, Role, User,
    },
    utils::{self, ApplicationError},
};

#[derive(Deserialize)]
pub struct EditEventForm {
    name: String,
    date: NaiveDate,
    from: NaiveTime,
    till: NaiveTime,
    location: i32,
    voluntarywachhabender: Option<bool>,
    voluntaryfuehrungsassistent: Option<bool>,
    amount: i16,
    clothing: String,
    note: Option<String>,
}

#[actix_web::post("/events/{id}/edit")]
pub async fn post(
    user: web::ReqData<User>,
    pool: web::Data<PgPool>,
    form: web::Form<EditEventForm>,
    path: web::Path<IdPath>,
) -> Result<impl Responder, ApplicationError> {
    if user.role != Role::Admin && user.role != Role::AreaManager {
        return Err(ApplicationError::Unauthorized);
    }

    let Some(event) = Event::read_by_id_including_location(pool.get_ref(), path.id).await? else {
        return Ok(HttpResponse::NotFound().finish());
    };

    if event.location_id != form.location {
        let Some(location) = Location::read_by_id(pool.get_ref(), form.location).await? else {
            return Ok(HttpResponse::BadRequest().body("Location does not exist"));
        };

        if user.role != Role::Admin && user.area_id != location.area_id {
            return Ok(HttpResponse::BadRequest().body("Can't use location outside of your area"));
        }

        if event.location.as_ref().unwrap().area_id != location.area_id {
            return Ok(HttpResponse::BadRequest()
                .body("Can't change to a location outside of previous location area"));
        }
    }

    let changeset = EventChangeset {
        date: form.date,
        amount_of_posten: form.amount,
        clothing: form.clothing.clone(),
        location_id: form.location,
        time: (form.from, form.till),
        name: form.name.clone(),
        note: form
            .note
            .clone()
            .and_then(|n| if n.len() != 0 { Some(n) } else { None }),
        voluntary_wachhabender: form.voluntarywachhabender.unwrap_or(false),
        voluntary_fuehrungsassistent: form.voluntaryfuehrungsassistent.unwrap_or(false),
    };

    let assignments_for_event = Assignment::read_all_by_event(pool.get_ref(), event.id).await?;

    let mut common_time = (
        NaiveTime::parse_from_str("00:00", "%R").unwrap(),
        NaiveTime::parse_from_str("23:59", "%R").unwrap(),
    );
    for assignment in &assignments_for_event {
        let availability = Availabillity::read_by_id(pool.get_ref(), assignment.availabillity_id)
            .await?
            .unwrap();
        let all_assignments =
            Assignment::read_all_by_availabillity(pool.get_ref(), assignment.availabillity_id)
                .await?;

        if all_assignments.len() == 1 {
            if availability.start_time.is_some() && availability.end_time.is_some() {
                let start = availability.start_time.unwrap();
                let end = availability.end_time.unwrap();

                if start > common_time.0 {
                    common_time.0 = start;
                }

                if end < common_time.1 {
                    common_time.1 = end;
                }
            }
        } else {
            let mut slots = if availability.start_time.is_some() && availability.end_time.is_some()
            {
                vec![(
                    availability.start_time.as_ref().unwrap().clone(),
                    availability.end_time.as_ref().unwrap().clone(),
                )]
            } else {
                vec![(
                    NaiveTime::parse_from_str("00:00", "%R").unwrap(),
                    NaiveTime::parse_from_str("23:59", "%R").unwrap(),
                )]
            };
            for a in all_assignments
                .iter()
                .filter(|x| x.event_id != assignment.event_id)
            {
                let (fit, rest) = slots
                    .into_iter()
                    .partition(|s| s.0 >= a.start_time && s.1 <= a.end_time);
                slots = rest;
                let fit = fit.first().unwrap();

                if fit.0 != a.start_time {
                    slots.push((fit.0, a.start_time));
                }

                if fit.1 != a.end_time {
                    slots.push((a.end_time, fit.1));
                }
            }

            let slot = slots
                .into_iter()
                .find(|s| s.0 >= assignment.start_time && s.1 <= assignment.end_time)
                .unwrap();

            if slot.0 > common_time.0 {
                common_time.0 = slot.0;
            }

            if slot.1 < common_time.1 {
                common_time.1 = slot.1;
            }
        }
    }

    let context = Some(EventContext {
        date_in_db: event.date,
        common_min_max_available_time: common_time,
        // safe as max amount of posten can be only 100
        amount_of_assigned_posten: assignments_for_event
            .iter()
            .filter(|a| a.function == Function::Posten)
            .count() as i16,
        wachhabender_assigned: assignments_for_event
            .iter()
            .any(|a| a.function == Function::Wachhabender),
        fuehrungsassistent_assigned: assignments_for_event
            .iter()
            .any(|a| a.function == Function::Fuehrungsassistent),
    });

    if let Err(e) = changeset.validate_with(&context) {
        return Ok(HttpResponse::BadRequest().body(e.to_string()));
    };

    if event.start_time != changeset.time.0 || event.end_time != changeset.time.1 {
        for a in assignments_for_event {
            let c = AssignmentChangeset {
                function: a.function,
                time: changeset.time.clone(),
            };
            Assignment::update(pool.get_ref(), a.event_id, a.availabillity_id, c).await?;
        }
    }

    Event::update(pool.get_ref(), event.id, changeset).await?;

    let url = utils::get_return_url_for_date(&form.date);
    println!("redirecto to {url}");
    Ok(HttpResponse::Found()
        .insert_header((LOCATION, url.clone()))
        .insert_header(("HX-LOCATION", url))
        .finish())
}