# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# MIT License. See license.txt

from __future__ import unicode_literals
"""docfield utililtes"""

import frappe

def rename(doctype, fieldname, newname):
	"""rename docfield"""
	df = frappe.db.sql("""select * from tabDocField where parent=%s and fieldname=%s""",
		(doctype, fieldname), as_dict=1)
	if not df:
		return
	
	df = df[0]
	
	if frappe.db.get_value('DocType', doctype, 'issingle'):	
		update_single(df, newname)
	else:
		update_table(df, newname)
		update_parent_field(df, newname)

def update_single(f, new):
	"""update in tabSingles"""
	frappe.db.begin()
	frappe.db.sql("""update tabSingles set field=%s where doctype=%s and field=%s""",
		(new, f['parent'], f['fieldname']))
	frappe.db.commit()

def update_table(f, new):
	"""update table"""
	query = get_change_column_query(f, new)
	if query:
		frappe.db.sql(query)
	
def update_parent_field(f, new):
	"""update 'parentfield' in tables"""
	if f['fieldtype']=='Table':
		frappe.db.begin()
		frappe.db.sql("""update `tab%s` set parentfield=%s where parentfield=%s""" \
			% (f['options'], '%s', '%s'), (new, f['fieldname']))
		frappe.db.commit()
	
def get_change_column_query(f, new):
	"""generate change fieldname query"""
	desc = frappe.db.sql("desc `tab%s`" % f['parent'])
	for d in desc:
		if d[0]== f['fieldname']:
			return 'alter table `tab%s` change `%s` `%s` %s' % \
				(f['parent'], f['fieldname'], new, d[1])