/* eslint max-len:0 */

// Oracle Query Builder & Compiler
// ------
import { assign, isPlainObject, isEmpty, isString, map, reduce, compact } from 'lodash'
import inherits from 'inherits';
import QueryCompiler from '../../../query/compiler';
import * as helpers from '../../../helpers';
import { ReturningHelper } from '../utils';

const components = [
  'columns', 'join', 'where', 'union', 'group', 'having', 'order', 'lock'
];

// Query Compiler
// -------

// Set the "Formatter" to use for the queries,
// ensuring that all parameterized values (even across sub-queries)
// are properly built into the same query.
function QueryCompiler_Oracle(client, builder) {
  QueryCompiler.call(this, client, builder)
}
inherits(QueryCompiler_Oracle, QueryCompiler)

assign(QueryCompiler_Oracle.prototype, {

  // Compiles an "insert" query, allowing for multiple
  // inserts using a single query statement.
  insert() {
    let insertValues = this.single.insert || []
    let { returning } = this.single;

    if (!Array.isArray(insertValues) && isPlainObject(this.single.insert)) {
      insertValues = [this.single.insert]
    }

    // always wrap returning argument in array
    if (returning && !Array.isArray(returning)) {
      returning = [returning];
    }

    if (Array.isArray(insertValues) && insertValues.length === 1 && isEmpty(insertValues[0])) {
      return this._addReturningToSqlAndConvert(`insert into ${this.tableName} (${this.formatter.wrap(this.single.returning)}) values (default)`, returning, this.tableName);
    }

    if (isEmpty(this.single.insert) && typeof this.single.insert !== 'function') {
      return '';
    }

    const insertData = this._prepInsert(insertValues);

    const sql = {};

    if (isString(insertData)) {
      return this._addReturningToSqlAndConvert(`insert into ${this.tableName} ${insertData}`, returning);
    }

    if (insertData.values.length === 1) {
      return this._addReturningToSqlAndConvert(`insert into ${this.tableName} (${this.formatter.columnize(insertData.columns)}) values (${this.formatter.parameterize(insertData.values[0])})`, returning, this.tableName);
    }

    const insertDefaultsOnly = (insertData.columns.length === 0);

    sql.sql = 'begin ' + map(insertData.values, (value) => {
      let returningHelper;
      const parameterizedValues = !insertDefaultsOnly ? this.formatter.parameterize(value, this.client.valueForUndefined) : '';
      const returningValues = Array.isArray(returning) ? returning : [returning];
      let subSql = `insert into ${this.tableName} `;

      if (returning) {
        returningHelper = new ReturningHelper(returningValues.join(':'));
        sql.outParams = (sql.outParams || []).concat(returningHelper);
      }

      if (insertDefaultsOnly) {
        // no columns given so only the default value
        subSql += `(${this.formatter.wrap(this.single.returning)}) values (default)`;
      } else {
        subSql += `(${this.formatter.columnize(insertData.columns)}) values (${parameterizedValues})`;
      }
      subSql += (returning ? ` returning ROWID into ${this.formatter.parameter(returningHelper)}` : '');

      // pre bind position because subSql is an execute immediate parameter
      // later position binding will only convert the ? params

      subSql = this.formatter.client.positionBindings(subSql);

      const parameterizedValuesWithoutDefault = parameterizedValues.replace('DEFAULT, ', '').replace(', DEFAULT', '');
      return `execute immediate '${subSql.replace(/'/g, "''")}` +
        ((parameterizedValuesWithoutDefault || returning) ? '\' using ' : '') +
        parameterizedValuesWithoutDefault +
        ((parameterizedValuesWithoutDefault && returning) ? ', ' : '') +
        (returning ? 'out ?' : '') + ';';
    }).join(' ') + 'end;';

    if (returning) {
      sql.returning = returning;
      // generate select statement with special order by to keep the order because 'in (..)' may change the order
      sql.returningSql = `select ${this.formatter.columnize(returning)}` +
        ' from ' + this.tableName +
        ' where ROWID in (' + sql.outParams.map((v, i) => `:${i + 1}`).join(', ') + ')' +
        ' order by case ROWID ' + sql.outParams.map((v, i) => `when CHARTOROWID(:${i + 1}) then ${i}`).join(' ') + ' end';
    }

    return sql;
  },

  // Update method, including joins, wheres, order & limits.
  update() {
    const updates = this._prepUpdate(this.single.update);
    const where = this.where();
    let { returning } = this.single;
    const sql = `update ${this.tableName}` +
      ' set ' + updates.join(', ') +
      (where ? ` ${where}` : '');

    if (!returning) {
      return sql;
    }

    // always wrap returning argument in array
    if (returning && !Array.isArray(returning)) {
      returning = [returning];
    }

    return this._addReturningToSqlAndConvert(sql, returning, this.tableName);
  },

  // Compiles a `truncate` query.
  truncate() {
    return `truncate table ${this.tableName}`;
  },

  forUpdate() {
    return 'for update';
  },

  forShare() {
    // lock for share is not directly supported by oracle
    // use LOCK TABLE .. IN SHARE MODE; instead
    helpers.warn('lock for share is not supported by oracle dialect');
    return '';
  },

  // Compiles a `columnInfo` query.
  columnInfo() {
    const column = this.single.columnInfo;
    return {
      sql: 'select COLUMN_NAME, DATA_TYPE, CHAR_COL_DECL_LENGTH, NULLABLE from USER_TAB_COLS where TABLE_NAME = :1',
      bindings: [this.single.table],
      output(resp) {
        const out = reduce(resp, function(columns, val) {
          columns[val.COLUMN_NAME] = {
            type: val.DATA_TYPE,
            maxLength: val.CHAR_COL_DECL_LENGTH,
            nullable: (val.NULLABLE === 'Y')
          };
          return columns;
        }, {});
        return column && out[column] || out;
      }
    };
  },

  select() {
    const statements = map(components, (component) => {
      return this[component]();
    });
    const query = compact(statements).join(' ');
    return this._surroundQueryWithLimitAndOffset(query);
  },

  aggregate(stmt) {
    const val = stmt.value;
    const splitOn = val.toLowerCase().indexOf(' as ');
    const distinct = stmt.aggregateDistinct ? 'distinct ' : '';
    // Allows us to speciy an alias for the aggregate types.
    if (splitOn !== -1) {
      const col = val.slice(0, splitOn);
      const alias = val.slice(splitOn + 4);
      return stmt.method + '(' + distinct + this.formatter.wrap(col) + ') ' + this.formatter.wrap(alias);
    }
    return stmt.method + '(' + distinct + this.formatter.wrap(val) + ')';
  },

  // for single commands only
  _addReturningToSqlAndConvert(sql, returning, tableName) {
    const res = {
      sql
    };

    if (!returning) {
      return res;
    }

    const returningValues = Array.isArray(returning) ? returning : [returning];
    const returningHelper = new ReturningHelper(returningValues.join(':'));
    res.sql = sql + ' returning ROWID into ' + this.formatter.parameter(returningHelper);
    res.returningSql = `select ${this.formatter.columnize(returning)} from ${tableName} where ROWID = :1`;
    res.outParams = [returningHelper];
    res.returning = returning;
    return res;
  },

  _surroundQueryWithLimitAndOffset(query) {
    let { limit } = this.single
    const { offset } = this.single
    const hasLimit = (limit || limit === 0 || limit === '0');
    limit = +limit;

    if (!hasLimit && !offset) return query;
    query = query || "";

    if (hasLimit && !offset) {
      return `select * from (${query}) where rownum <= ${this.formatter.parameter(limit)}`;
    }

    const endRow = +(offset) + (hasLimit ? limit : 10000000000000);

    return "select * from " +
           "(select row_.*, ROWNUM rownum_ from (" + query + ") row_ " +
           "where rownum <= " + this.formatter.parameter(endRow) + ") " +
           "where rownum_ > " + this.formatter.parameter(offset);
  }

})

// Compiles the `select` statement, or nested sub-selects
// by calling each of the component compilers, trimming out
// the empties, and returning a generated query string.
QueryCompiler_Oracle.prototype.first = QueryCompiler_Oracle.prototype.select

export default QueryCompiler_Oracle;