import { assign } from 'lodash'
import assert from 'assert';

// JoinClause
// -------

// The "JoinClause" is an object holding any necessary info about a join,
// including the type, and any associated tables & columns being joined.
function JoinClause(table, type, schema) {
  this.schema = schema;
  this.table = table;
  this.joinType = type;
  this.and = this;
  this.clauses = [];
}

assign(JoinClause.prototype, {

  grouping: 'join',

  // Adds an "on" clause to the current join object.
  on(first, operator, second) {
    if (typeof first === 'function') {
      this.clauses.push({
        type: 'onWrapped',
        value: first,
        bool: this._bool()
      });
      return this;
    }

    let data;
    const bool = this._bool();
    switch (arguments.length) {
      case 1:  {
        if (typeof first === 'object' && typeof first.toSQL !== 'function') {
          const keys = Object.keys(first);
          let i = -1;
          const method = bool === 'or' ? 'orOn' : 'on'
          while (++i < keys.length) {
            this[method](keys[i], first[keys[i]])
          }
          return this;
        } else {
          data = {type: 'onRaw', value: first, bool};
        }
        break;
      }
      case 2:  data = {type: 'onBasic', column: first, operator: '=', value: operator, bool}; break;
      default: data = {type: 'onBasic', column: first, operator, value: second, bool};
    }
    this.clauses.push(data);
    return this;
  },

  // Adds a "using" clause to the current join.
  using(column) {
    return this.clauses.push({type: 'onUsing', column, bool: this._bool()});
  },

  /*// Adds an "and on" clause to the current join object.
  andOn() {
    return this.on.apply(this, arguments);
  },*/

  // Adds an "or on" clause to the current join object.
  orOn(first, operator, second) {
    return this._bool('or').on.apply(this, arguments);
  },

  onBetween(column, values) {
    assert(Array.isArray(values), 'The second argument to onBetween must be an array.')
    assert(values.length === 2, 'You must specify 2 values for the onBetween clause')
    this.clauses.push({
      type: 'onBetween',
      column,
      value: values,
      bool: this._bool(),
      not: this._not()
    });
    return this;
  },

  onNotBetween(column, values) {
    return this._not(true).onBetween(column, values);
  },

  orOnBetween(column, values) {
    return this._bool('or').onBetween(column, values);
  },

  orOnNotBetween(column, values) {
    return this._bool('or')._not(true).onBetween(column, values);
  },

  onIn(column, values) {
    if (Array.isArray(values) && values.length === 0) return this.where(this._not());
    this.clauses.push({
      type: 'onIn',
      column,
      value: values,
      not: this._not(),
      bool: this._bool()
    });
    return this;
  },

  onNotIn(column, values) {
    return this._not(true).onIn(column, values);
  },

  orOnIn(column, values) {
    return this._bool('or').onIn(column, values);
  },

  orOnNotIn(column, values) {
    return this._bool('or')._not(true).onIn(column, values);
  },

  onNull(column) {
    this.clauses.push({
      type: 'onNull',
      column,
      not: this._not(),
      bool: this._bool()
    });
    return this;
  },

  orOnNull(callback) {
    return this._bool('or').onNull(callback);
  },

  onNotNull(callback) {
    return this._not(true).onNull(callback);
  },

  orOnNotNull(callback) {
    return this._not(true)._bool('or').onNull(callback);
  },

  onExists(callback) {
    this.clauses.push({
      type: 'onExists',
      value: callback,
      not: this._not(),
      bool: this._bool()
    });
    return this;
  },

  orOnExists(callback) {
    return this._bool('or').onExists(callback);
  },

  onNotExists(callback) {
    return this._not(true).onExists(callback);
  },

  orOnNotExists(callback) {
    return this._not(true)._bool('or').onExists(callback);
  },

  // Explicitly set the type of join, useful within a function when creating a grouped join.
  type(type) {
    this.joinType = type;
    return this;
  },

  _bool(bool) {
    if (arguments.length === 1) {
      this._boolFlag = bool;
      return this;
    }
    const ret = this._boolFlag || 'and';
    this._boolFlag = 'and';
    return ret;
  },

  _not(val) {
    if (arguments.length === 1) {
      this._notFlag = val;
      return this;
    }
    const ret = this._notFlag;
    this._notFlag = false;
    return ret;
  },

})

Object.defineProperty(JoinClause.prototype, 'or', {
  get () {
    return this._bool('or');
  }
});

JoinClause.prototype.andOn = JoinClause.prototype.on
JoinClause.prototype.andOnIn = JoinClause.prototype.onIn
JoinClause.prototype.andOnNotIn = JoinClause.prototype.onNotIn
JoinClause.prototype.andOnNull = JoinClause.prototype.onNull
JoinClause.prototype.andOnNotNull = JoinClause.prototype.onNotNull
JoinClause.prototype.andOnExists = JoinClause.prototype.onExists
JoinClause.prototype.andOnNotExists = JoinClause.prototype.onNotExists
JoinClause.prototype.andOnBetween = JoinClause.prototype.onBetween
JoinClause.prototype.andOnNotBetween = JoinClause.prototype.onNotBetween

export default JoinClause;