// file: kb-app-demo-desktop/frontend/ts/demo_store_block_pagination.ts
// version: 1

export type StoreBlockMetadata = {
    blockSize: number;
    blockIndex: number;
    totalRows: string;
    totalBlocks: number;
    nextCursor: string | null;
};

export type StoreBlockState = {
    blockSize: number;
    currentBlock: number;
    totalBlocks: number;
    totalRows: string;
    nextCursor: string | null;
    cursors: Map<number, string | null>;
};

export type StoreBlockControls = {
    firstSelector: string;
    previousSelector: string;
    nextSelector: string;
    summarySelector: string;
};

export function createStoreBlockState(): StoreBlockState {
    return {
        blockSize: 500,
        currentBlock: 0,
        totalBlocks: 0,
        totalRows: "0",
        nextCursor: null,
        cursors: new Map<number, string | null>([[1, null]]),
    };
}

export function resetStoreBlockState(state: StoreBlockState): void {
    state.blockSize = 500;
    state.currentBlock = 0;
    state.totalBlocks = 0;
    state.totalRows = "0";
    state.nextCursor = null;
    state.cursors = new Map<number, string | null>([[1, null]]);
}

export function applyStoreBlockMetadata(
    state: StoreBlockState,
    metadata: StoreBlockMetadata,
    controls: StoreBlockControls,
): void {
    state.blockSize = metadata.blockSize;
    state.currentBlock = metadata.blockIndex;
    state.totalBlocks = metadata.totalBlocks;
    state.totalRows = metadata.totalRows;
    state.nextCursor = metadata.nextCursor;
    if (metadata.blockIndex > 0 && metadata.nextCursor !== null) {
        state.cursors.set(metadata.blockIndex + 1, metadata.nextCursor);
    }
    renderStoreBlockControls(state, controls);
}

export function renderStoreBlockControls(
    state: StoreBlockState,
    controls: StoreBlockControls,
): void {
    const firstButton = document.querySelector<HTMLButtonElement>(controls.firstSelector);
    const previousButton = document.querySelector<HTMLButtonElement>(controls.previousSelector);
    const nextButton = document.querySelector<HTMLButtonElement>(controls.nextSelector);
    const summary = document.querySelector<HTMLElement>(controls.summarySelector);
    const hasRows = state.totalBlocks > 0;
    if (firstButton !== null) {
        firstButton.disabled = !hasRows || state.currentBlock <= 1;
    }
    if (previousButton !== null) {
        previousButton.disabled = !hasRows || state.currentBlock <= 1;
    }
    if (nextButton !== null) {
        nextButton.disabled = state.nextCursor === null;
    }
    if (summary !== null) {
        summary.textContent = hasRows
            ? `Bloc ${state.currentBlock} / ${state.totalBlocks} · ${state.totalRows} résultat(s) · ${state.blockSize}/bloc`
            : `Bloc 0 / 0 · 0 résultat · ${state.blockSize}/bloc`;
    }
}

export function markStoreBlockFiltersDirty(
    state: StoreBlockState,
    controls: StoreBlockControls,
): void {
    resetStoreBlockState(state);
    const firstButton = document.querySelector<HTMLButtonElement>(controls.firstSelector);
    const previousButton = document.querySelector<HTMLButtonElement>(controls.previousSelector);
    const nextButton = document.querySelector<HTMLButtonElement>(controls.nextSelector);
    const summary = document.querySelector<HTMLElement>(controls.summarySelector);
    if (firstButton !== null) {
        firstButton.disabled = true;
    }
    if (previousButton !== null) {
        previousButton.disabled = true;
    }
    if (nextButton !== null) {
        nextButton.disabled = true;
    }
    if (summary !== null) {
        summary.textContent = "Filtres modifiés — rechargez le premier bloc.";
    }
}

export function cursorForBlock(state: StoreBlockState, blockIndex: number): string | null | undefined {
    return state.cursors.get(blockIndex);
}