var t = require('./typecheck');


// "name" | "table"."name" | "schema"."table"."name"
function name (column, table, schema) {
	if (this.typecheck) t.typecheck('name', [column, table, schema]);

	var result = [];
	schema && result.push(this.quotes(schema));
	table && result.push(this.quotes(table));
	column && result.push(this.quotes(column));
	return result.join('.');
}

// name,name,...
function names (columns, table, schema) {
	if (this.typecheck) t.typecheck('names', [columns, table, schema]);

	var result = [];
	for (var i=0; i < columns.length; i++) {
		result.push(this.name(columns[i],table,schema));
	}

	return result.join(',');
}

// schema
function schema (name) {
	if (this.typecheck) t.typecheck('schema', [name]);
	if (this.dialect != 'pg') return;
	return name||this._schema;
}

// column as name
function as (column, name) {
	if (this.typecheck) t.typecheck('as', [column, name]);
	return [column,'as',name].join(' ');
}

// table alias
function alias (table, name) {
	if (this.typecheck) t.typecheck('alias', [table, name]);
	return [table,name].join(' ');
}

// func(arg1,arg2,...)
function func (name, args, sep) {
	if (this.typecheck) t.typecheck('func', [name, args, sep]);
	if ('string'===typeof args) args = [args];
	return name+'('+args.join(sep||',')+')';
}

// select col1,col2
function select (args) {
	if (this.typecheck) t.typecheck('select', [args]);
	if ('string'===typeof args) args = [args];
	return 'select '+args.join();
}

// from table
function from (table) {
	if (this.typecheck) t.typecheck('from', [table]);
	return 'from '+table;
}

// left join table on pk1=fk1 and pk2=fk2 ...
function join (table, args, type) {
	this.typecheck && t.typecheck('join', [table, args, type]);
	if ('string'===typeof args) args = [args];
	var result = ['join',table,'on',args.join(' and ')];
	if (type) result.splice(0,0,type);
	return result.join(' ');
}

// a = b
function eq (a, b) {
	if (this.typecheck) t.typecheck('eq', [a, b]);
	return a+'='+b;
}

// col = val
function eqv (column, value) {
	if (this.typecheck) t.typecheck('eqv', [column, value]);
	if (value===undefined||value===null) value = null;
	if ('string'===typeof value) value = this.string(value);
	if ('boolean'===typeof value)
		value = (this.dialect == 'pg')
			? ((value == false) ? this.wrap('f') : this.wrap('t'))
			: ((value == false) ? 0 : 1);

	return column+'='+value;
}

// group by arg1,arg2 ...
function groupby (args) {
	if (this.typecheck) t.typecheck('groupby', [args]);
	if ('string'===typeof args) args = [args];
	return 'group by '+args.join();
}

// order by col1 asc, col2 desc ...
function orderby (args, order) {
	if (this.typecheck) t.typecheck('orderby', [args, order]);
	
	var o = (order&&'string'===typeof order) ? order : '';
	var result = [];

	if ('string'===typeof args) {
		result = o ? [args+' '+o] : [args];
	}
	else if (args instanceof Array) {
		for (var i=0; i < args.length; i++) {
			if ('string'===typeof args[i]) {
				o ? result.push(args[i]+' '+o) : result.push(args[i]);
			}
			else if ('object'===typeof args[i]) {
				var key = Object.keys(args[i])[0];
				result.push(key+' '+args[i][key]);
			}
		}
	}
	else if (args instanceof Object) {
		var key = Object.keys(args)[0];
		result = [key+' '+args[key]];
	}

	return 'order by '+result.join();
}

// limit 1,2
function limit (a, b) {
	if (this.typecheck) t.typecheck('limit', [a, b]);
	return (this.dialect == 'pg')
		? ['limit',b,'offset',a].join(' ')
		: 'limit '+[a,b].join();
}

// and expr
function and (expr) {
	if (this.typecheck) t.typecheck('and', [expr]);
	if ('string'===typeof expr) return 'and '+expr;
	if (expr instanceof Array) return expr.join(' and ');
}

// or expr
function or (expr) {
	if (this.typecheck) t.typecheck('or', [expr]);
	if ('string'===typeof expr) return 'or '+expr;
	if (expr instanceof Array) return expr.join(' or ');
}

// between a and b
function between (a, b) {
	if (this.typecheck) t.typecheck('between', [a, b]);
	return ['between',a,'and',b].join(' ');
}

// like str
function like (str) {
	if (this.typecheck) t.typecheck('like', [str]);
	return 'like '+str;
}

// where expr1 and expr2 ...
function where (expr, operator) {
	if (this.typecheck) t.typecheck('where', [expr, operator]);
	if ('string'===typeof expr) return 'where '+expr;
	return 'where ' + expr.join(' '+(operator||'and')+' ');
}

// insert into tbl (col1,col2) values (val1,val2) ...
function insert (table, columns, values) {
	if (this.typecheck) t.typecheck('insert', [table, columns, values]);
	if ('string'===typeof columns) columns = [columns];
	if ('string'===typeof values) values = [values];

	var get = function get (values) {
		var result = [];
		for (var i=0; i < values.length; i++) {
			var value = values[i];
			if ('string'===typeof value
				// X\'blob\' \'\\xblob\'
				&& value.indexOf("X\'") != 0 && value.indexOf("\'\\x") != 0)
				value = this.string(value);
			if (value===null) value = 'null';
			result.push(value);
		}
		return result;
	}.bind(this);

	var result = [];
	if (values[0] instanceof Array) {
		for (var i=0; i < values.length; i++) {
			var val = get(values[i]);
			result.push('('+val.join()+')');
		}
	}
	else {
		var val = get(values);
		result.push('('+val.join()+')');
	}

	return ['insert','into',table,'('+columns.join()+')','values',result.join()].join(' ');
}

// update tbl set col1=val1,col2=val2 ...
function update (table, columns, values) {
	if (this.typecheck) t.typecheck('update', [table, columns, values]);
	if ('string'===typeof columns) {
		columns = [columns];
		values = [values];
	}
	var result = [];
	for (var i=0; i < columns.length; i++) {
		var value = ('string'===typeof values[i]
			// X\'blob\' \'\\xblob\'
			&& values[i].indexOf("X\'") != 0 && values[i].indexOf("\'\\x") != 0)
			? this.string(values[i]) : values[i];
		result.push(columns[i]+'='+value);
	}
	return ['update',table,'set',result.join()].join(' ');
}


exports = module.exports = function () {
	this.name = name;
	this.names = names;
	this.schema = schema;
	this.as = as;
	this.alias = alias;
	this.func = func;
	this.select = select;
	this.from = from;
	this.join = join;
	this.eq = eq;
	this.eqv = eqv;
	this.groupby = groupby;
	this.orderby = orderby;
	this.limit = limit;
	this.and = and;
	this.or = or;
	this.between = between;
	this.like = like;
	this.where = where;
	this.insert = insert;
	this.update = update;
	// in (arg1,arg2,...)
	this.in = function (args) {
		if (this.typecheck) t.typecheck('in', [args]);
		if (!(args instanceof Array)) args = [args];

		var result = [];
		for (var i=0; i < args.length; i++) {
			'string'===typeof args[i]
				? result.push(this.string(args[i]))
				: result.push(args[i]);
		}

		return 'in('+result.join()+')';
	};
	// delete from tbl
	this.delete = function (table) {
		if (this.typecheck) t.typecheck('delete', [table]);
		return ['delete','from',table].join(' ');
	};
};