import {
    RECIEVE_SHOP_PACKAGES,
    RECEIVE_SHOPS,
    SELECT_SHOP,
    REQUEST_SHOP_PACKAGES,
    SHOP_PAGE_SIZE,
    SEARCH_SHOP_PACKAGES_REQUEST,
    SEARCH_SHOP_PACKAGES_RESULT,
} from '../../constants/coMarketConstants';

const moduleReducers = {};

moduleReducers[REQUEST_SHOP_PACKAGES] = (state, action) => {
    return Object.assign({}, state, {
        isLoading: action.isLoading,
        shopSearch: false,
    });
};

moduleReducers[RECIEVE_SHOP_PACKAGES] = (state = {}, action) => {

    // implement paging
    // paging is implemented in a way that requested number of packages is {page_size + 1}
    // this way if retrieved number of packages is greater than page size there may be more packages

    const shopPage = action.page || 1;
    let shopPackages = [];
    let shopPackagesDiff = [];
    let retrievedShopPackages = action.shopPackages || [];

    // append newly retrieved packages to existing ones if more packages are loaded
    if (state.shopPage && shopPage > state.shopPage) {
        shopPackages = state.loadedShopPackages || [];
        // get ignored packages from previous request
        const oldShopPackagesDiff = state.shopPackagesDiff || [];
        // append packages ignored previous time to the beginning
        retrievedShopPackages = oldShopPackagesDiff.concat(retrievedShopPackages);
    }

    // if number of packages is greater than page size there may be more of them to retrieve
    const hasMorePages = retrievedShopPackages.length > SHOP_PAGE_SIZE;

    // ignore all packages over limit of page size (they will be displayed at the beginning of the next request)
    while (retrievedShopPackages.length > SHOP_PAGE_SIZE) {
        shopPackagesDiff.push(retrievedShopPackages.pop());
    }

    // append packages from this page to existing ones
    shopPackages = shopPackages.concat(retrievedShopPackages);

    return Object.assign({}, state, {
        shopPackages: shopPackages,
        loadedShopPackages: shopPackages,
        shopPackagesDiff: shopPackagesDiff,
        shopPage: shopPage,
        shopSearch: false,
        shopHasMorePackages: hasMorePages,
        isLoading: action.isLoading
    });
};

moduleReducers[SEARCH_SHOP_PACKAGES_REQUEST] = (state, action) => {
    return Object.assign({}, state, {
        shopSearch: true,
        isLoading: action.isLoading
    });
};

moduleReducers[SEARCH_SHOP_PACKAGES_RESULT] = (state, action) => {
    return Object.assign({}, state, {
        shopPackages: action.shopPackages || [],
        shopSearch: true,
        isLoading: action.isLoading
    });
};

moduleReducers[RECEIVE_SHOPS] = (state, action) => {
    return Object.assign({}, state, {
        shops: action.shops
    });
};

moduleReducers[SELECT_SHOP] = (state, action) => {
    return Object.assign({}, state, {
        selectedShop: action.selectedShop
    });
};

const coMarketPackagesReducer = (state = {}, action) => {

    return moduleReducers[action.type] ? moduleReducers[action.type](state, action) : state;
};

export default coMarketPackagesReducer;