// (C) 2007-2018 GoodData Corporation
import get from "lodash/get";
import find from "lodash/find";
import omit from "lodash/omit";
import cloneDeep from "lodash/cloneDeep";
import { XhrModule } from "./xhr";
import { ExecutionModule } from "./execution";
import { IAdHocItemDescription, IStoredItemDescription, ItemDescription } from "./interfaces";

const REQUEST_DEFAULTS = {
    types: ["attribute", "metric", "fact"],
    paging: {
        offset: 0,
    },
};

const LOAD_DATE_DATASET_DEFAULTS = {
    includeUnavailableDateDataSetsCount: true,
    includeAvailableDateAttributes: true,
};

/**
 * Convert specific params in options to "requiredDataSets" structure. For more details look into
 * res file https://github.com/gooddata/gdc-bear/blob/develop/resources/specification/internal/catalog.res
 *
 * @param options Supported keys in options are:
 * <ul>
 * <li>dataSetIdentifier - in value is string identifier of dataSet - this leads to CUSTOM type
 * <li>returnAllDateDataSets - true value means to return ALL values without dataSet differentiation
 * <li>returnAllRelatedDateDataSets - only related date dataSets are loaded across all dataSets
 * <li>by default we get PRODUCTION dataSets
 * </ul>
 * @returns {Object} "requiredDataSets" object hash.
 */
const getRequiredDataSets = (options: any) => {
    if (get(options, "returnAllRelatedDateDataSets")) {
        return {};
    }

    if (get(options, "returnAllDateDataSets")) {
        return { requiredDataSets: { type: "ALL" } };
    }

    if (get(options, "dataSetIdentifier")) {
        return {
            requiredDataSets: {
                type: "CUSTOM",
                customIdentifiers: [get(options, "dataSetIdentifier")],
            },
        };
    }

    return { requiredDataSets: { type: "PRODUCTION" } };
};

interface IColumnsAndDefinitions {
    columns: string[];
    definitions: any[];
}

const buildItemDescriptionObjects = ({ columns, definitions }: IColumnsAndDefinitions): ItemDescription[] => {
    if (!columns) {
        return [];
    }

    return columns.map((column: string) => {
        const definition = find(
            definitions,
            ({ metricDefinition }) => metricDefinition.identifier === column,
        );
        const maql = get(definition, "metricDefinition.expression");
        if (maql) {
            return { expression: maql };
        }
        return { uri: column };
    });
};

const isStoredItemDescription = (
    itemDescription: ItemDescription,
): itemDescription is IStoredItemDescription => {
    return !!(itemDescription as IStoredItemDescription).uri;
};

const isAdHocItemDescription = (
    itemDescription: ItemDescription,
): itemDescription is IAdHocItemDescription => {
    return !!(itemDescription as IAdHocItemDescription).expression;
};

const unwrapItemDescriptionObject = (itemDescription: ItemDescription): string => {
    if (isStoredItemDescription(itemDescription)) {
        return itemDescription.uri;
    }
    if (isAdHocItemDescription(itemDescription)) {
        return itemDescription.expression;
    }
    throw new Error("Item description can only have expression or uri");
};

export class CatalogueModule {
    constructor(private xhr: XhrModule, private execution: ExecutionModule) {}

    public loadItems(projectId: string, options = {}) {
        const request = omit(
            {
                ...REQUEST_DEFAULTS,
                ...options,
                ...getRequiredDataSets(options),
            },
            ["dataSetIdentifier", "returnAllDateDataSets", "attributesMap"],
        );

        const mdObj = get(cloneDeep(options), "bucketItems");
        const attributesMap = get(options, "attributesMap");
        const hasBuckets = get(mdObj, "buckets") !== undefined;
        if (hasBuckets) {
            return this.loadItemDescriptions(projectId, mdObj, attributesMap).then((bucketItems: any) =>
                this.loadCatalog(projectId, { ...request, bucketItems }),
            );
        }

        return this.loadCatalog(projectId, request);
    }

    public async loadDateDataSets(projectId: string, options: any) {
        const mdObj = cloneDeep(options).bucketItems;
        const bucketItems = mdObj
            ? await this.loadItemDescriptions(projectId, mdObj, get(options, "attributesMap"), true)
            : undefined;

        const omittedOptions = [
            "filter",
            "types",
            "paging",
            "dataSetIdentifier",
            "returnAllDateDataSets",
            "returnAllRelatedDateDataSets",
            "attributesMap",
        ];
        // includeObjectsWithTags has higher priority than excludeObjectsWithTags,
        // so when present omit excludeObjectsWithTags
        if (options.includeObjectsWithTags) {
            omittedOptions.push("excludeObjectsWithTags");
        }

        const request = omit(
            {
                ...LOAD_DATE_DATASET_DEFAULTS,
                ...REQUEST_DEFAULTS,
                ...options,
                ...getRequiredDataSets(options),
                bucketItems,
            },
            omittedOptions,
        );

        return this.requestDateDataSets(projectId, request);
    }

    /**
     * Loads item description objects and returns them
     *
     * @internal
     * @private
     *
     * @param projectId {string}
     * @param mdObj metadata object containing buckets, visualization class, properties etc.
     * @param attributesMap contains map of attributes where the keys are the attributes display forms URIs
     * @param removeDateItems {boolean} skip date items
     * @return ItemDescription which is either `{ uri: string }` or `{ expression: string }`
     */
    public async loadItemDescriptionObjects(
        projectId: string,
        mdObj: any,
        attributesMap: any,
        removeDateItems = false,
    ): Promise<ItemDescription[]> {
        const definitionsAndColumns = await this.execution.mdToExecutionDefinitionsAndColumns(
            projectId,
            mdObj,
            { attributesMap, removeDateItems },
        );

        return buildItemDescriptionObjects(definitionsAndColumns);
    }

    /**
     * ItemDescription is either URI or MAQL expression
     * https://github.com/gooddata/gdc-bear/blob/185.4/resources/specification/md/obj.res#L284
     *
     * @param projectId {string}
     * @param mdObj metadata object containing buckets, visualization class, properties etc.
     * @param attributesMap contains map of attributes where the keys are the attributes display forms URIs
     * @param removeDateItems {boolean} skip date items
     * @deprecated
     */
    public async loadItemDescriptions(
        projectId: string,
        mdObj: any,
        attributesMap: any,
        removeDateItems = false,
    ): Promise<string[]> {
        const itemDescriptions = await this.loadItemDescriptionObjects(
            projectId,
            mdObj,
            attributesMap,
            removeDateItems,
        );

        return itemDescriptions.map(unwrapItemDescriptionObject);
    }

    private requestDateDataSets(projectId: string, dateDataSetsRequest: any) {
        const uri = `/gdc/internal/projects/${projectId}/loadDateDataSets`;

        return this.xhr
            .post(uri, { data: { dateDataSetsRequest } })
            .then(r => r.getData())
            .then(data => data.dateDataSetsResponse);
    }

    private loadCatalog(projectId: string, catalogRequest: any) {
        const uri = `/gdc/internal/projects/${projectId}/loadCatalog`;

        return this.xhr
            .post(uri, { data: { catalogRequest } })
            .then(r => r.getData())
            .then(data => data.catalogResponse);
    }
}