import { listen } from "rkgk/framework.js";

function numChunksInRectangle(rect, chunkSize) {
    let leftChunk = Math.floor(rect.left / chunkSize);
    let topChunk = Math.floor(rect.top / chunkSize);
    let rightChunk = Math.ceil(rect.right / chunkSize);
    let bottomChunk = Math.ceil(rect.bottom / chunkSize);
    let numX = rightChunk - leftChunk;
    let numY = bottomChunk - topChunk;
    return numX * numY;
}

function* chunksInRectangle(rect, chunkSize) {
    let leftChunk = Math.floor(rect.left / chunkSize);
    let topChunk = Math.floor(rect.top / chunkSize);
    let rightChunk = Math.ceil(rect.right / chunkSize);
    let bottomChunk = Math.ceil(rect.bottom / chunkSize);
    for (let chunkY = topChunk; chunkY < bottomChunk; ++chunkY) {
        for (let chunkX = leftChunk; chunkX < rightChunk; ++chunkX) {
            yield [chunkX, chunkY];
        }
    }
}

export function renderToChunksInArea(layer, renderArea, renderToPixmap) {
    for (let [chunkX, chunkY] of chunksInRectangle(renderArea, layer.chunkSize)) {
        let chunk = layer.getOrCreateChunk(chunkX, chunkY);
        if (chunk == null) continue;

        let translationX = -chunkX * layer.chunkSize;
        let translationY = -chunkY * layer.chunkSize;
        let result = renderToPixmap(chunk.pixmap, translationX, translationY);
        chunk.markModified();
        if (result.status != "ok") return result;
    }

    return { status: "ok" };
}

export function dotterRenderArea(wall, dotter) {
    let halfPaintArea = wall.paintArea / 2;
    return {
        left: dotter.toX - halfPaintArea,
        top: dotter.toY - halfPaintArea,
        right: dotter.toX + halfPaintArea,
        bottom: dotter.toY + halfPaintArea,
    };
}

export function selfController(interactionQueue, wall, layer, event) {
    let renderArea = null;
    return {
        async runScribble(renderToPixmap) {
            interactionQueue.push({ kind: "scribble" });
            if (renderArea != null) {
                let numChunksToRender = numChunksInRectangle(renderArea, layer.chunkSize);
                let result = renderToChunksInArea(layer, renderArea, renderToPixmap);
                if (!layer.canFitNewChunks(numChunksToRender)) {
                    console.debug("too many chunks rendered; committing interaction early");
                    event.earlyCommitInteraction();
                }
                return result;
            } else {
                console.debug("render area is empty, nothing will be rendered");
            }
            return { status: "ok" };
        },

        async runDotter() {
            let dotter = await event.continueAsDotter();
            interactionQueue.push({
                kind: "dotter",
                from: { x: dotter.fromX, y: dotter.fromY },
                to: { x: dotter.toX, y: dotter.toY },
                num: dotter.num,
            });
            renderArea = dotterRenderArea(wall, dotter);
            return dotter;
        },
    };
}