use domain::{DataSourceId, Value, WidgetConfig, WidgetId, WidgetState};
use std::collections::HashMap;

#[derive(Default)]
pub struct DataProjection {
    current: HashMap<WidgetId, WidgetState>,
}

impl DataProjection {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn get_state(&self, widget_id: WidgetId) -> Option<&WidgetState> {
        self.current.get(&widget_id)
    }

    pub fn apply_poll_result(
        &mut self,
        data_source_id: DataSourceId,
        raw: &Value,
        widget_configs: &[WidgetConfig],
    ) -> Vec<(WidgetId, WidgetState)> {
        let mut changed = Vec::new();

        for config in widget_configs {
            if config.data_source_id != data_source_id {
                continue;
            }

            let new_state = config.extract(raw);

            let is_changed = self
                .current
                .get(&config.id)
                .is_none_or(|prev| *prev != new_state);

            if is_changed {
                self.current.insert(config.id, new_state.clone());
                changed.push((config.id, new_state));
            }
        }

        changed
    }
}