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//! Extracts data from the current state.

use crate::{
    context::MapContext,
    render::{
        eventually::{Eventually, Eventually::Initialized},
        tile_view_pattern::{ViewTileSources, WgpuTileViewPattern, DEFAULT_TILE_SIZE},
    },
};

pub fn tile_view_pattern_system(
    MapContext {
        view_state, world, ..
    }: &mut MapContext,
) {
    let Some((Initialized(tile_view_pattern), view_tile_sources)) = world
        .resources
        .query::<(&Eventually<WgpuTileViewPattern>, &ViewTileSources)>()
    else {
        return;
    };
    let view_region =
        view_state.create_view_region(view_state.zoom().zoom_level(DEFAULT_TILE_SIZE));

    if let Some(view_region) = &view_region {
        let zoom = view_state.zoom();

        let view_tiles =
            tile_view_pattern.generate_pattern(view_region, view_tile_sources, zoom, world);

        // TODO: Can we &mut borrow initially somehow instead of here?
        let Some(Initialized(tile_view_pattern)) = world
            .resources
            .query_mut::<&mut Eventually<WgpuTileViewPattern>>()
        else {
            return;
        };

        log::trace!("Tiles in view: {}", view_tiles.len());

        tile_view_pattern.update_pattern(view_tiles);
    }
}