/* eslint max-len:0 no-console:0*/

// MySQL Table Builder & Compiler
// -------
import inherits from 'inherits';
import TableCompiler from '../../../schema/tablecompiler';
import * as helpers from '../../../helpers';
import Promise from '../../../promise';

import { assign } from 'lodash'

// Table Compiler
// ------

function TableCompiler_MySQL() {
  TableCompiler.apply(this, arguments);
}
inherits(TableCompiler_MySQL, TableCompiler);

assign(TableCompiler_MySQL.prototype, {

  createQuery(columns, ifNot) {
    const createStatement = ifNot ? 'create table if not exists ' : 'create table ';
    const { client } = this;
    let conn = {};
    let sql = createStatement + this.tableName() + ' (' + columns.sql.join(', ') + ')';

    // Check if the connection settings are set.
    if (client.connectionSettings) {
      conn = client.connectionSettings;
    }

    const charset = this.single.charset || conn.charset || '';
    const collation = this.single.collate || conn.collate || '';
    const engine = this.single.engine  || '';

    // var conn = builder.client.connectionSettings;
    if (charset)   sql += ` default character set ${charset}`;
    if (collation) sql += ` collate ${collation}`;
    if (engine)    sql += ` engine = ${engine}`;

    if (this.single.comment) {
      const comment = (this.single.comment || '');
      if (comment.length > 60) helpers.warn('The max length for a table comment is 60 characters');
      sql += ` comment = '${comment}'`;
    }

    this.pushQuery(sql);
  },

  addColumnsPrefix: 'add ',

  dropColumnPrefix: 'drop ',

  // Compiles the comment on the table.
  comment(comment) {
    this.pushQuery(`alter table ${this.tableName()} comment = '${comment}'`);
  },

  changeType() {
    // alter table + table + ' modify ' + wrapped + '// type';
  },

  // Renames a column on the table.
  renameColumn(from, to) {
    const compiler = this;
    const table = this.tableName();
    const wrapped = this.formatter.wrap(from) + ' ' + this.formatter.wrap(to);

    this.pushQuery({
      sql: `show fields from ${table} where field = ` +
        this.formatter.parameter(from),
      output(resp) {
        const column = resp[0];
        const runner = this;
        return compiler.getFKRefs(runner).get(0)
          .then(refs =>
            Promise.try(function () {
              if (!refs.length) { return; }
              return compiler.dropFKRefs(runner, refs);
            }).then(function () {
              let sql = `alter table ${table} change ${wrapped} ${column.Type}`;

              if(String(column.Null).toUpperCase() !== 'YES') {
                sql += ` NOT NULL`
              }
              if(column.Default !== void 0 && column.Default !== null) {
                sql += ` DEFAULT '${column.Default}'`
              }

              return runner.query({
                sql
              });
            }).then(function () {
              if (!refs.length) { return; }
              return compiler.createFKRefs(runner, refs.map(function (ref) {
                if (ref.REFERENCED_COLUMN_NAME === from) {
                  ref.REFERENCED_COLUMN_NAME = to;
                }
                if (ref.COLUMN_NAME === from) {
                  ref.COLUMN_NAME = to;
                }
                return ref;
              }));
            })
          );
      }
    });
  },

  getFKRefs (runner) {
    const formatter = this.client.formatter();
    const sql = 'SELECT KCU.CONSTRAINT_NAME, KCU.TABLE_NAME, KCU.COLUMN_NAME, '+
              '       KCU.REFERENCED_TABLE_NAME, KCU.REFERENCED_COLUMN_NAME, '+
              '       RC.UPDATE_RULE, RC.DELETE_RULE '+
              'FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU '+
              'JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS AS RC '+
              '       USING(CONSTRAINT_NAME)' +
              'WHERE KCU.REFERENCED_TABLE_NAME = ' + formatter.parameter(this.tableNameRaw) + ' '+
              '  AND KCU.CONSTRAINT_SCHEMA = ' + formatter.parameter(this.client.database()) + ' '+
              '  AND RC.CONSTRAINT_SCHEMA = ' + formatter.parameter(this.client.database());

    return runner.query({
      sql,
      bindings: formatter.bindings
    });
  },

  dropFKRefs (runner, refs) {
    const formatter = this.client.formatter();

    return Promise.all(refs.map(function (ref) {
      const constraintName = formatter.wrap(ref.CONSTRAINT_NAME);
      const tableName = formatter.wrap(ref.TABLE_NAME);
      return runner.query({
        sql: `alter table ${tableName} drop foreign key ${constraintName}`
      });
    }));
  },
  createFKRefs (runner, refs) {
    const formatter = this.client.formatter();

    return Promise.all(refs.map(function (ref) {
      const tableName = formatter.wrap(ref.TABLE_NAME);
      const keyName = formatter.wrap(ref.CONSTRAINT_NAME);
      const column = formatter.columnize(ref.COLUMN_NAME);
      const references = formatter.columnize(ref.REFERENCED_COLUMN_NAME);
      const inTable = formatter.wrap(ref.REFERENCED_TABLE_NAME);
      const onUpdate = ` ON UPDATE ${ref.UPDATE_RULE}`;
      const onDelete = ` ON DELETE ${ref.DELETE_RULE}`;

      return runner.query({
        sql: `alter table ${tableName} add constraint ${keyName} ` +
          'foreign key (' + column + ') references ' + inTable + ' (' + references + ')' + onUpdate + onDelete
      });
    }));
  },
  index(columns, indexName) {
    indexName = indexName ? this.formatter.wrap(indexName) : this._indexCommand('index', this.tableNameRaw, columns);
    this.pushQuery(`alter table ${this.tableName()} add index ${indexName}(${this.formatter.columnize(columns)})`);
  },

  primary(columns, indexName) {
    indexName = indexName ? this.formatter.wrap(indexName) : this._indexCommand('primary', this.tableNameRaw, columns);
    this.pushQuery(`alter table ${this.tableName()} add primary key ${indexName}(${this.formatter.columnize(columns)})`);
  },

  unique(columns, indexName) {
    indexName = indexName ? this.formatter.wrap(indexName) : this._indexCommand('unique', this.tableNameRaw, columns);
    this.pushQuery(`alter table ${this.tableName()} add unique ${indexName}(${this.formatter.columnize(columns)})`);
  },

  // Compile a drop index command.
  dropIndex(columns, indexName) {
    indexName = indexName ? this.formatter.wrap(indexName) : this._indexCommand('index', this.tableNameRaw, columns);
    this.pushQuery(`alter table ${this.tableName()} drop index ${indexName}`);
  },

  // Compile a drop foreign key command.
  dropForeign(columns, indexName) {
    indexName = indexName ? this.formatter.wrap(indexName) : this._indexCommand('foreign', this.tableNameRaw, columns);
    this.pushQuery(`alter table ${this.tableName()} drop foreign key ${indexName}`);
  },

  // Compile a drop primary key command.
  dropPrimary() {
    this.pushQuery(`alter table ${this.tableName()} drop primary key`);
  },

  // Compile a drop unique key command.
  dropUnique(column, indexName) {
    indexName = indexName ? this.formatter.wrap(indexName) : this._indexCommand('unique', this.tableNameRaw, column);
    this.pushQuery(`alter table ${this.tableName()} drop index ${indexName}`);
  }

})

export default TableCompiler_MySQL;