import {
    DSQL_FieldSchemaType,
    DSQL_MYSQL_SHOW_COLUMNS_Type,
} from "../../types";
import dbHandler from "../../functions/backend/dbHandler";
import defaultFieldsRegexp from "../../functions/dsql/default-fields-regexp";
import generateColumnDescription from "./generateColumnDescription";

type Param = {
    dbFullName: string;
    tableName: string;
    fields: DSQL_FieldSchemaType[];
    clone?: boolean;
    allExistingColumns: DSQL_MYSQL_SHOW_COLUMNS_Type[];
};

/**
 * Handle DATASQUIREL schema fields for current table
 * ===================================================
 * @description Iterate through each field object and
 * perform operations
 */
export default async function handleDSQLSchemaFields({
    dbFullName,
    tableName,
    fields,
    allExistingColumns,
}: Param) {
    let sql = `ALTER TABLE \`${dbFullName}\`.\`${tableName}\``;

    for (let i = 0; i < fields.length; i++) {
        const column = fields[i];
        // const prevColumn = fields[i - 1];
        // const nextColumn = fields[i + 1];

        const { fieldName, dataType, foreignKey } = column;

        if (!fieldName) continue;
        if (defaultFieldsRegexp.test(fieldName)) continue;

        let updateText = "";

        const existingColumnIndex = allExistingColumns?.findIndex(
            (_column, _index) => _column.Field === fieldName
        );

        const existingColumn =
            existingColumnIndex >= 0
                ? allExistingColumns[existingColumnIndex]
                : undefined;

        let { fieldEntryText } = generateColumnDescription({
            columnData: column,
        });

        /**
         * @description Modify Column(Field) if it already exists
         * in MYSQL database
         */
        if (existingColumn?.Field) {
            const { Field, Type } = existingColumn;

            updateText += ` MODIFY COLUMN ${fieldEntryText}`;
        } else {
            /**
             * @description Append new column to the end of existing columns
             */
            updateText += ` ADD COLUMN ${fieldEntryText}`;
        }

        /**
         * @description Pust SQL code snippet to updateTableQueryArray Array
         * Add a comma(,) to separate from the next snippet
         */
        if (updateText.match(/./)) {
            sql += " " + updateText + ",";
        }
    }

    const finalSQL = sql.replace(/\,$/, "");

    const updateTable = await dbHandler({
        query: finalSQL,
    });
}