use chrono::Utc;

use domain::models::ScheduledSlot;
use domain::value_objects::ChannelId;
use domain::{DomainResult, ScheduleEngineService};

use super::deps::ScheduleDeps;
use super::queries::GetEpgQuery;

/// Return EPG (electronic program guide) data for a channel.
///
/// Returns the slots that overlap the active schedule's validity window.
/// Returns an empty vec when no schedule is active.
pub async fn execute(
    deps: &ScheduleDeps,
    query: GetEpgQuery,
) -> DomainResult<Vec<ScheduledSlot>> {
    let channel_id = ChannelId::from(query.channel_id);
    let now = Utc::now();

    let schedule = match deps.schedule_query.find_active(channel_id, now).await? {
        Some(s) => s,
        None => return Ok(vec![]),
    };

    let slots = ScheduleEngineService::get_epg(
        &schedule,
        schedule.valid_from(),
        schedule.valid_until(),
    );

    Ok(slots.into_iter().cloned().collect())
}

#[cfg(test)]
#[path = "tests/get_epg.rs"]
mod tests;