import {
    DSQL_DatabaseSchemaType,
    DSQL_FieldSchemaType,
    DSQL_MYSQL_SHOW_COLUMNS_Type,
} from "../../types";
import dbHandler from "../../functions/backend/dbHandler";
import defaultFieldsRegexp from "../../functions/dsql/default-fields-regexp";
import { writeUpdatedDbSchema } from "../createDbFromSchema/grab-required-database-schemas";
import _ from "lodash";

type Param = {
    dbFullName: string;
    tableName: string;
    fields: DSQL_FieldSchemaType[];
    dbSchema: DSQL_DatabaseSchemaType;
    userId?: number | string | null;
};

/**
 * Handle MYSQL Columns (Fields)
 * ===================================================
 * @description Now handle all fields/columns
 */
export default async function handleMariaDBExistingColumns({
    dbFullName,
    tableName,
    fields,
    dbSchema,
    userId,
}: Param) {
    let upToDateTableFieldsArray = _.cloneDeep(fields);

    let allExistingColumns: DSQL_MYSQL_SHOW_COLUMNS_Type[] = (await dbHandler({
        query: `SHOW COLUMNS FROM \`${dbFullName}\`.\`${tableName}\``,
    })) as DSQL_MYSQL_SHOW_COLUMNS_Type[];

    /**
     * @description Iterate through every existing column
     */
    for (let e = 0; e < allExistingColumns.length; e++) {
        const { Field } = allExistingColumns[e];

        if (Field.match(defaultFieldsRegexp)) continue;

        /**
         * @description This finds out whether the fieldName corresponds with the MSQL Field name
         * if the fildName doesn't match any MYSQL Field name, the field is deleted.
         */
        let existingEntry = upToDateTableFieldsArray.find(
            (column) =>
                column.fieldName === Field || column.originName === Field
        );

        if (!existingEntry) {
            await dbHandler({
                query: `ALTER TABLE \`${dbFullName}\`.\`${tableName}\` DROP COLUMN \`${Field}\``,
            });
            continue;
        }

        if (existingEntry) {
            /**
             * @description Check if Field name has been updated
             */
            if (existingEntry.updatedField && existingEntry.fieldName) {
                await dbHandler({
                    query: `ALTER TABLE \`${dbFullName}\`.\`${tableName}\` RENAME COLUMN \`${existingEntry.originName}\` TO \`${existingEntry.fieldName}\``,
                });

                console.log(
                    `Column Renamed from "${existingEntry.originName}" to "${existingEntry.fieldName}"`
                );

                /**
                 * Update Db Schema
                 * ===================================================
                 * @description Update Db Schema after renaming column
                 */
                try {
                    const updatedSchemaData = _.cloneDeep(dbSchema);

                    const targetTableIndex = updatedSchemaData.tables.findIndex(
                        (table) => table.tableName === tableName
                    );
                    const targetFieldIndex = updatedSchemaData.tables[
                        targetTableIndex
                    ].fields.findIndex(
                        (field) => field.fieldName === existingEntry.fieldName
                    );

                    delete updatedSchemaData.tables[targetTableIndex].fields[
                        targetFieldIndex
                    ]["originName"];
                    delete updatedSchemaData.tables[targetTableIndex].fields[
                        targetFieldIndex
                    ]["updatedField"];

                    /**
                     * @description Set New Table Fields Array
                     */
                    upToDateTableFieldsArray =
                        updatedSchemaData.tables[targetTableIndex].fields;

                    if (userId) {
                        writeUpdatedDbSchema({
                            dbSchema: updatedSchemaData,
                            userId,
                        });
                    }

                    allExistingColumns = (await dbHandler({
                        query: `SHOW COLUMNS FROM \`${dbFullName}\`.\`${tableName}\``,
                    })) as DSQL_MYSQL_SHOW_COLUMNS_Type[];
                } catch (error: any) {
                    console.log("Update table error =>", error.message);
                }

                ////////////////////////////////////////
            }

            continue;
        }
    }

    return { upToDateTableFieldsArray, allExistingColumns };
}