# -*- coding: utf-8 -*-
# Copyright (c) 2015, Frappe Technologies and contributors
# For lice

from __future__ import unicode_literals
import frappe
from frappe import _

class OverlapError(frappe.ValidationError): pass

def validate_overlap_for(doc, doctype, fieldname, value=None):
	"""Checks overlap for specified feild.
	
	:param fieldname: Checks Overlap for this feild 
	"""
	
	existing = get_overlap_for(doc, doctype, fieldname, value)
	if existing:
		frappe.throw(_("This {0} conflicts with {1} for {2} {3}").format(doc.doctype, existing.name,
			doc.meta.get_label(fieldname) if not value else fieldname , value or doc.get(fieldname)), OverlapError)
	
def get_overlap_for(doc, doctype, fieldname, value=None):
	"""Returns overlaping document for specified feild.
	
	:param fieldname: Checks Overlap for this feild 
	"""

	existing = frappe.db.sql("""select name, from_time, to_time from `tab{0}`
		where `{1}`=%(val)s and schedule_date = %(schedule_date)s and
		(
			(from_time > %(from_time)s and from_time < %(to_time)s) or
			(to_time > %(from_time)s and to_time < %(to_time)s) or
			(%(from_time)s > from_time and %(from_time)s < to_time) or
			(%(from_time)s = from_time and %(to_time)s = to_time))
		and name!=%(name)s""".format(doctype, fieldname),
		{
			"schedule_date": doc.schedule_date,
			"val": value or doc.get(fieldname),
			"from_time": doc.from_time,
			"to_time": doc.to_time,
			"name": doc.name or "No Name"
		}, as_dict=True)

	return existing[0] if existing else None