// @ts-check

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const path = require("path");

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const noDatabaseDbHandler = require("./utils/noDatabaseDbHandler");
const varDatabaseDbHandler = require("./utils/varDatabaseDbHandler");
const createTable = require("./utils/createTable");
const updateTable = require("./utils/updateTable");

/** ****************************************************************************** */
/** ****************************************************************************** */
/** ****************************************************************************** */
/** ****************************************************************************** */
/** ****************************************************************************** */
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/**
 * Create database from Schema
 * ==============================================================================
 * @description Create database from Schema. This function is called when the user
 * runs the "dsql create" command. `NOTE`: there must be a "dsql.schema.json" file
 * in the root of the project for this function to work
 *
 * @param {import("../../types/database-schema.td").DSQL_DatabaseSchemaType[]} dbSchema - An array of database schema objects
 */
async function createDbFromSchema(dbSchema) {
    /**
     * Grab Schema
     *
     * @description Grab Schema
     */

    if (!dbSchema || !Array.isArray(dbSchema) || !dbSchema[0]) {
        console.log("Invalid DB schema data");
        return;
    }

    for (let i = 0; i < dbSchema.length; i++) {
        /** @type {import("../../types/database-schema.td").DSQL_DatabaseSchemaType} */
        const database = dbSchema[i];
        const { dbFullName, tables } = database;

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        /** @type {{ dbFullName: string }[] | null} */
        const dbCheck = await noDatabaseDbHandler({ query: `SELECT SCHEMA_NAME AS dbFullName FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = '${dbFullName}'` });

        if (dbCheck && dbCheck[0]?.dbFullName) {
            // Database Exists
        } else {
            const newDatabase = await noDatabaseDbHandler({ query: `CREATE DATABASE IF NOT EXISTS \`${dbFullName}\` CHARACTER SET utf8mb4 COLLATE utf8mb4_bin` });
        }

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        /**
         * Select all tables
         * @type {{ TABLE_NAME: string }[] | null}
         * @description Select All tables in target database
         */
        const allTables = await noDatabaseDbHandler({ query: `SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA='${dbFullName}'` });

        let tableDropped;

        if (!allTables) {
            console.log("No Tables to Update");
            continue;
        }

        for (let tb = 0; tb < allTables.length; tb++) {
            const { TABLE_NAME } = allTables[tb];

            /**
             * @description Check if TABLE_NAME is part of the tables contained
             * in the user schema JSON. If it's not, the table is either deleted
             * or the table name has been recently changed
             */
            if (!tables.filter((_table) => _table.tableName === TABLE_NAME)[0]) {
                const oldTableFilteredArray = tables.filter((_table) => _table.tableNameOld && _table.tableNameOld === TABLE_NAME);

                /**
                 * @description Check if this table has been recently renamed. Rename
                 * table id true. Drop table if false
                 */
                if (oldTableFilteredArray && oldTableFilteredArray[0]) {
                    console.log("Renaming Table");
                    await varDatabaseDbHandler({
                        queryString: `RENAME TABLE \`${oldTableFilteredArray[0].tableNameOld}\` TO \`${oldTableFilteredArray[0].tableName}\``,
                        database: dbFullName,
                    });
                } else {
                    console.log(`Dropping Table from ${dbFullName}`);
                    // deepcode ignore reDOS: <NO user input>
                    await varDatabaseDbHandler({
                        queryString: `DROP TABLE \`${TABLE_NAME}\``,
                        database: dbFullName,
                    });

                    tableDropped = true;
                }
            }
        }

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        /**
         * @description Iterate through each table and perform table actions
         */
        for (let t = 0; t < tables.length; t++) {
            const table = tables[t];

            if (tableDropped) continue;

            const { tableName, fields, indexes } = table;

            /**
             * @description Check if table exists
             */
            const tableCheck = await varDatabaseDbHandler({
                queryString: `
                    SELECT EXISTS (
                        SELECT 
                        TABLE_NAME
                        FROM 
                        information_schema.TABLES 
                        WHERE 
                        TABLE_SCHEMA = ? AND
                        TABLE_NAME = ?
                        ) AS tableExists`,
                queryValuesArray: [dbFullName, table.tableName],
                database: dbFullName,
            });

            ////////////////////////////////////////

            if (tableCheck && tableCheck[0]?.tableExists > 0) {
                /**
                 * @description Update table if table exists
                 */
                const updateExistingTable = await updateTable({
                    dbFullName: dbFullName,
                    tableName: tableName,
                    tableInfoArray: fields,
                    dbSchema,
                    tableIndexes: indexes,
                    tableIndex: t,
                });

                if (table.childrenTables && table.childrenTables[0]) {
                    for (let ch = 0; ch < table.childrenTables.length; ch++) {
                        const childTable = table.childrenTables[ch];

                        const updateExistingChildTable = await updateTable({
                            dbFullName: childTable.dbNameFull,
                            tableName: childTable.tableName,
                            tableInfoArray: fields,
                            dbSchema,
                            tableIndexes: indexes,
                            clone: true,
                        });

                        // console.log(updateExistingChildTable);
                    }
                }

                ////////////////////////////////////////
            } else {
                ////////////////////////////////////////

                /**
                 * @description Create new Table if table doesnt exist
                 */
                const createNewTable = await createTable({
                    tableName: tableName,
                    tableInfoArray: fields,
                    varDatabaseDbHandler,
                    dbFullName: dbFullName,
                    dbSchema,
                });

                if (indexes && indexes[0]) {
                    /**
                     * Handle DATASQUIREL Table Indexes
                     * ===================================================
                     * @description Iterate through each datasquirel schema
                     * table index(if available), and perform operations
                     */
                    if (indexes && indexes[0]) {
                        for (let g = 0; g < indexes.length; g++) {
                            const { indexType, indexName, indexTableFields, alias } = indexes[g];

                            if (!alias?.match(/./)) continue;

                            /**
                             * @type {DSQL_MYSQL_SHOW_INDEXES_Type[] | null}
                             * @description All indexes from MYSQL db
                             */
                            const allExistingIndexes = await varDatabaseDbHandler({
                                queryString: `SHOW INDEXES FROM \`${tableName}\``,
                                database: dbFullName,
                            });

                            /**
                             * @description Check for existing Index in MYSQL db
                             */
                            try {
                                const existingKeyInDb = allExistingIndexes ? allExistingIndexes.filter((indexObject) => indexObject.Key_name === alias) : null;
                                if (!existingKeyInDb?.[0]) throw new Error("This Index Does not Exist");
                            } catch (error) {
                                /**
                                 * @description Create new index if determined that it
                                 * doesn't exist in MYSQL db
                                 */
                                await varDatabaseDbHandler({
                                    queryString: `CREATE${indexType.match(/fullText/i) ? " FULLTEXT" : ""} INDEX \`${alias}\` ON ${tableName}(${indexTableFields
                                        .map((nm) => nm.value)
                                        .map((nm) => `\`${nm}\``)
                                        .join(",")}) COMMENT 'schema_index'`,
                                    database: dbFullName,
                                });
                            }
                        }
                    }
                }
            }

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        }
    }

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}

/** ****************************************************************************** */
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module.exports = createDbFromSchema;