import {DatabaseConnection} from "./DatabaseConnection";
import {DatabaseColumnDefinition, DatabaseDefinition} from "./DatabaseDefinition";
import {Container} from "../Container/Container";
import {Logger} from "log4js";

export class DatabaseUpdater {
    constructor(private readonly database: DatabaseConnection) {}
    
    public ensureAvaliablity(definitions: Iterable<DatabaseDefinition>) {
        for (const definition of definitions) {
            this.ensureDefinition(definition);
        }
    }
    
    private ensureDefinition(definition: DatabaseDefinition) {
        if (this.database.hasTable(definition.name)) {
            this.ensureTableColumns(definition);
            return;
        }
        
        this.createTable(definition);
    }
    
    private ensureTableColumns(definition: DatabaseDefinition) {
        const DBSQLColumns = this.database.fetchAll<{}, {name: string, type: string}>(
            `PRAGMA table_info("${definition.name}")`
        );
        
        if (!DBSQLColumns) {
            Container.get<Logger>("logger").log("Request failed...");
            return;
        }
        
        const missingColumns = definition.columns.filter(
            (column: DatabaseColumnDefinition) => {
                return !DBSQLColumns.some((dbColumn: DatabaseColumnDefinition) => {
                    return column.name === dbColumn.name
                });
            }
        )
        
        if (missingColumns.length < 1) {
            Container.get<Logger>("logger").log(`No new columns found for ${definition.name}`)
            return;
        }
        
        const columnsSQL = missingColumns.map((column: DatabaseColumnDefinition) => {
            const values = [
                "ADD",
                column.name,
                column.type,
                column.primaryKey ? `PRIMARY KEY` : '',
                column.notNull ? 'NOT NULL' : '',
                column.autoIncrement ? 'AUTOINCREMENT' : '',
            ]

            return values.join(' ');
        }).join(', ');
        
        const sql = `ALTER TABLE ${definition.name} ${columnsSQL}`;
        this.database.execute(sql);
    }


    private createTable(definition: DatabaseDefinition) {
        const columnsSQL = definition.columns.map((column: DatabaseColumnDefinition) => {
            const values = [
                column.name,
                column.type,
                column.primaryKey ? `PRIMARY KEY` : '',
                column.notNull ? 'NOT NULL' : '',
                column.autoIncrement ? 'AUTOINCREMENT' : '',
            ]
            
            return values.join(' ');
        }).join(', ');
        
        const sql = `CREATE TABLE IF NOT EXISTS ${definition.name} (${columnsSQL})`;
        const result = this.database.execute(sql);
    }
}