import { Knex } from "knex";
import { db } from "@db/db";

export interface RequestQuery {
    length: string;
    start: string;
    order: { column: string; dir: string }[];
    columns: { [key: string]: { data: string; searchable: string } };
    search: { value: string };
    filters: { [key: string]: any };
}

export interface ResponseQuery {
    query: Knex.QueryBuilder;
    recordsTotal: number | string;
    recordsFiltered: number | string;
}

type FilterConfig = {
    [key: string]: (value: any) => Knex.QueryBuilder;
};

export const buildDatatableQuery = async (request: { query: RequestQuery }, query: Knex.QueryBuilder, tableName: string): Promise<ResponseQuery> => {
    const size: number = parseInt(request.query.length) || 10;
    const start: number = parseInt(request.query.start);
    const order: string = (
        request.query.order && request.query.columns
        [request.query.order[0].column].data
    ) || 'id'
    const direction: string = (request.query.order && request.query.order[0].dir) || "asc";
    const search: string = request.query.search.value;

    const recordsTotalResult = await query.clone().count("* as count").first();
    const recordsTotal = recordsTotalResult ? recordsTotalResult.count : 0;

    const filterConfig: FilterConfig = {
        active: (value: string) => query.where('active', '=', value),
    };

    if (request.query.filters) {
        Object.keys(request.query.filters).forEach((filterName: any) => {
            const filterValue = request.query.filters[filterName];
            if (filterConfig[filterName] && filterValue) {
                query = filterConfig[filterName](filterValue);
            }
        });
    }

    if (search) {
        console.log("applying search: " + search)
        console.log("columns: " + JSON.stringify(request.query.columns, null, 4));
        query = query.where(builder => {
            Object.values(request.query.columns)
                .filter(column => column.searchable === "true")
                .forEach((col, index) =>
                    index === 0
                        ? builder.where(`${tableName}.${col.data}`, "like", `%${search}%`)
                        : builder.orWhere(`${tableName}.${col.data}`, "like", `%${search}%`)
                );
        });
    }

    const recordsFilteredResult = await query.clone().count("* as count").first();
    const recordsFiltered = recordsFilteredResult ? recordsFilteredResult.count : 0;

    query = query.orderBy(`${tableName}.${order}`, direction).limit(size).offset(start);

    return {
        query,
        recordsTotal,
        recordsFiltered
    };
}