import * as path from 'path';
import * as fs from 'fs';
import {
  SystemDef,
  StorageDef,
  EndpointDef,
  Order,
  Filter,
  TableDef,
  ColumnDef,
  BelongsToDef,
  ManyToManyDef
} from '../systemGenService';

let outDir = 'test';

export function createDatabase(storageDef: StorageDef) {
  let tableCreationQueries: string[] = [];
  let tableDeletionQueries: string[] = [];
  for (let i in storageDef.tables) {
    tableCreationQueries.push(getTableCreationString(storageDef.tables[i]));
    tableDeletionQueries.push(getTableDeletionString(storageDef.tables[i]));
  }
  for (let i in storageDef.relations) {
    tableCreationQueries.push(getTableRelationsCreationString(storageDef.relations[i]));
    tableDeletionQueries.push(getTableRelationsDeletionString(storageDef.relations[i]))
  }
  tableCreationQueries.map((query: string) => {
    console.log(query);
  });

  tableDeletionQueries.map((query: string) => {
    console.log(query);
  });

  return {
    up: tableCreationQueries,
    down: tableDeletionQueries,
  };
}

function getTableCreationString(tableDef: TableDef): string {
  let primaryKeyString: string = `${tableDef.name}_id VARCHAR(36) PRIMARY KEY`;
  let columnString: string = `${primaryKeyString}`;
  let defaultColumns: string = `created DATETIME NOT NULL DEFAULT NOW(), modified DATETIME NOT NULL DEFAULT NOW()`
  let indexString: string = ``;

  // columns
  for (let i in tableDef.columns) {
    let column: ColumnDef = tableDef.columns[i];
    columnString = `${columnString}, ${createColumnString(column)}`;
  }

  // relations
  for (let i in tableDef.relations) {
    let relation: BelongsToDef = tableDef.relations[i];
    columnString = `${columnString}, ${relation.table}_id VARCHAR(36)`;
  }

  // default created & modified
  columnString = `${columnString}, ${defaultColumns}`;

  return `CREATE TABLE IF NOT EXISTS ${tableDef.name} (${columnString}${indexString !== '' ? ', ' + indexString : ''});`;
}

function getTableRelationsCreationString(relationsDef: ManyToManyDef): string {
  let columnString: string = `${relationsDef.left}_id VARCHAR(36) NOT NULL, ${relationsDef.right}_id VARCHAR(36) NOT NULL`;
  let indexString: string = `INDEX ${relationsDef.left}_id_index (${relationsDef.left}_id), INDEX ${relationsDef.right}_id_index (${relationsDef.right}_id)`;

  if (relationsDef.columns && relationsDef.columns.length) {
    for (let i in relationsDef.columns) {
      let column: ColumnDef = relationsDef.columns[i];
      columnString = `${columnString}, ${createColumnString(column)}`;
    }
  }

  return `CREATE TABLE IF NOT EXISTS ${relationsDef.left}_${relationsDef.right} (${columnString}${indexString !== '' ? ', ' + indexString : ''});`;
}

function createColumnString(column: ColumnDef) {
  const typeMap: {[type: string]: string} = {
    "blob": "BLOB",
    "boolean": "BOOLEAN",
    "date": "DATE",
    "dateTIME": "DATETIME",
    "number": "INT",
    "string": "VARCHAR(255)",
  };

  return `${column.name} ${typeMap[column.type]}${column.nullable ? '' : ' NOT NULL'}${column.default ? ' DEFAULT ' + column.default : ''}${column.autoIncrement ? ' AUTO_INCREMENT' : ''}${column.unique ? ' UNIQUE' : ''}`;
}

function getTableDeletionString(tableDef: TableDef): string {
  return `DROP TABLE IF EXISTS ${tableDef.name};`
}

function getTableRelationsDeletionString(relationsDef: ManyToManyDef) : string {
  return `DROP TABLE IF EXISTS ${relationsDef.left}_${relationsDef.right};`
}

function dateString() {
  let date = new Date();
  return `${date.getFullYear()}${date.getMonth() + 1}${date.getDate()}`;
}

export function writeMigrationsToFile(migrations: {up: string[], down: string[]}, outDir: string) {
  let migrationFileContents = `
--up
${migrations.up.join('\n')}
--down
${migrations.down.join('\n')}
  `;
  let migrationFilePath = path.join(process.cwd(), outDir, 'src', 'migrationJobs', `${dateString()}-create-database.sql`);
  fs.writeFileSync(migrationFilePath, migrationFileContents);
}