# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# License: GNU General Public License v3. See license.txt

from __future__ import unicode_literals
import frappe
from frappe import _
from frappe.utils import formatdate, format_datetime, getdate, get_datetime, nowdate, flt
from frappe.model.document import Document
from frappe.desk.form import assign_to
from erpnext.hr.doctype.salary_structure.salary_structure import make_salary_slip

class EmployeeBoardingController(Document):
	'''
		Create the project and the task for the boarding process
		Assign to the concerned person and roles as per the onboarding/separation template
	'''
	def validate(self):
		# remove the task if linked before submitting the form
		if self.amended_from:
			for activity in self.activities:
				activity.task = ''

	def on_submit(self):
		# create the project for the given employee onboarding
		project_name = _(self.doctype) + " : "
		if self.doctype == "Employee Onboarding":
			project_name += self.job_applicant
		else:
			project_name += self.employee
		project = frappe.get_doc({
				"doctype": "Project",
				"project_name": project_name,
				"expected_start_date": self.date_of_joining if self.doctype == "Employee Onboarding" else self.resignation_letter_date,
				"department": self.department,
				"company": self.company
			}).insert(ignore_permissions=True)
		self.db_set("project", project.name)

		# create the task for the given project and assign to the concerned person
		for activity in self.activities:
			task = frappe.get_doc({
					"doctype": "Task",
					"project": project.name,
					"subject": activity.activity_name + " : " + self.employee_name,
					"description": activity.description,
					"department": self.department,
					"company": self.company
				}).insert(ignore_permissions=True)
			activity.db_set("task", task.name)
			users = [activity.user] if activity.user else []
			if activity.role:
				user_list = frappe.db.sql_list('''select distinct(parent) from `tabHas Role`
					where parenttype='User' and role=%s''', activity.role)
				users = users + user_list

			# assign the task the users
			if users:
				self.assign_task_to_users(task, set(users))

	def assign_task_to_users(self, task, users):
		for user in users:
			args = {
				'assign_to' 	:	user,
				'doctype'		:	task.doctype,
				'name'			:	task.name,
				'description'	:	task.description or task.subject,
			}
			assign_to.add(args)

	def on_cancel(self):
		# delete task project
		for task in frappe.get_all("Task", filters={"project": self.project}):
			frappe.delete_doc("Task", task.name)
		frappe.delete_doc("Project", self.project)
		self.db_set('project', '')
		for activity in self.activities:
			activity.db_set("task", "")


@frappe.whitelist()
def get_onboarding_details(parent, parenttype):
	return frappe.get_list("Employee Boarding Activity",
		fields=["activity_name", "role", "user", "required_for_employee_creation", "description"],
		filters={"parent": parent, "parenttype": parenttype},
		order_by= "idx")

def set_employee_name(doc):
	if doc.employee and not doc.employee_name:
		doc.employee_name = frappe.db.get_value("Employee", doc.employee, "employee_name")

def update_employee(employee, details, date=None, cancel=False):
	internal_work_history = {}
	for item in details:
		fieldtype = frappe.get_meta("Employee").get_field(item.fieldname).fieldtype
		new_data = item.new if not cancel else item.current
		if fieldtype == "Date" and new_data:
			new_data = getdate(new_data)
		elif fieldtype =="Datetime" and new_data:
			new_data = get_datetime(new_data)
		setattr(employee, item.fieldname, new_data)
		if item.fieldname in ["department", "designation", "branch"]:
			internal_work_history[item.fieldname] = item.new
	if internal_work_history and not cancel:
		internal_work_history["from_date"] = date
		employee.append("internal_work_history", internal_work_history)
	return employee

@frappe.whitelist()
def get_employee_fields_label():
	fields = []
	for df in frappe.get_meta("Employee").get("fields"):
		if df.fieldtype in ["Data", "Date", "Datetime", "Float", "Int",
		"Link", "Percent", "Select", "Small Text"] and df.fieldname not in ["lft", "rgt", "old_parent"]:
			fields.append({"value": df.fieldname, "label": df.label})
	return fields

@frappe.whitelist()
def get_employee_field_property(employee, fieldname):
	if employee and fieldname:
		field = frappe.get_meta("Employee").get_field(fieldname)
		value = frappe.db.get_value("Employee", employee, fieldname)
		options = field.options
		if field.fieldtype == "Date":
			value = formatdate(value)
		elif field.fieldtype == "Datetime":
			value = format_datetime(value)
		return {
			"value" : value,
			"datatype" : field.fieldtype,
			"label" : field.label,
			"options" : options
		}
	else:
		return False

def validate_dates(doc, from_date, to_date):
	date_of_joining, relieving_date = frappe.db.get_value("Employee", doc.employee, ["date_of_joining", "relieving_date"])
	if getdate(from_date) > getdate(to_date):
		frappe.throw(_("To date can not be less than from date"))
	elif getdate(from_date) > getdate(nowdate()):
		frappe.throw(_("Future dates not allowed"))
	elif date_of_joining and getdate(from_date) < getdate(date_of_joining):
		frappe.throw(_("From date can not be less than employee's joining date"))
	elif relieving_date and getdate(to_date) > getdate(relieving_date):
		frappe.throw(_("To date can not greater than employee's relieving date"))

def validate_overlap(doc, from_date, to_date, company = None):
	query = """
		select name
		from `tab{0}`
		where name != %(name)s
		"""
	query += get_doc_condition(doc.doctype)

	if not doc.name:
		# hack! if name is null, it could cause problems with !=
		doc.name = "New "+doc.doctype

	overlap_doc = frappe.db.sql(query.format(doc.doctype),{
			"employee": doc.employee,
			"from_date": from_date,
			"to_date": to_date,
			"name": doc.name,
			"company": company
		}, as_dict = 1)

	if overlap_doc:
		exists_for = doc.employee
		if company:
			exists_for = company
		throw_overlap_error(doc, exists_for, overlap_doc[0].name, from_date, to_date)

def get_doc_condition(doctype):
	if doctype == "Compensatory Leave Request":
		return "and employee = %(employee)s and docstatus < 2 \
		and (work_from_date between %(from_date)s and %(to_date)s \
		or work_end_date between %(from_date)s and %(to_date)s \
		or (work_from_date < %(from_date)s and work_end_date > %(to_date)s))"
	elif doctype == "Leave Period":
		return "and company = %(company)s and (from_date between %(from_date)s and %(to_date)s \
			or to_date between %(from_date)s and %(to_date)s \
			or (from_date < %(from_date)s and to_date > %(to_date)s))"

def throw_overlap_error(doc, exists_for, overlap_doc, from_date, to_date):
	msg = _("A {0} exists between {1} and {2} (").format(doc.doctype,
		formatdate(from_date), formatdate(to_date)) \
		+ """ <b><a href="#Form/{0}/{1}">{1}</a></b>""".format(doc.doctype, overlap_doc) \
		+ _(") for {0}").format(exists_for)
	frappe.throw(msg)

def get_employee_leave_policy(employee):
	leave_policy = frappe.db.get_value("Employee", employee, "leave_policy")
	if not leave_policy:
		employee_grade = frappe.db.get_value("Employee", employee, "grade")
		if employee_grade:
			leave_policy = frappe.db.get_value("Employee Grade", employee_grade, "default_leave_policy")
			if not leave_policy:
				frappe.throw(_("Employee {0} of grade {1} have no default leave policy").format(employee, employee_grade))
		else:
			frappe.throw(_("Employee {0} has no grade to get default leave policy").format(employee))
	if leave_policy:
		return frappe.get_doc("Leave Policy", leave_policy)

def validate_tax_declaration(declarations):
	subcategories = []
	for declaration in declarations:
		if declaration.exemption_sub_category in  subcategories:
			frappe.throw(_("More than one selection for {0} not \
			allowed").format(declaration.exemption_sub_category), frappe.ValidationError)
		subcategories.append(declaration.exemption_sub_category)
		max_amount = frappe.db.get_value("Employee Tax Exemption Sub Category", \
		declaration.exemption_sub_category, "max_amount")
		if declaration.amount > max_amount:
			frappe.throw(_("Max exemption amount for {0} is {1}").format(\
			declaration.exemption_sub_category, max_amount), frappe.ValidationError)

def get_leave_period(from_date, to_date, company):
	leave_period = frappe.db.sql("""
		select name, from_date, to_date
		from `tabLeave Period`
		where company=%(company)s and is_active=1
			and (from_date between %(from_date)s and %(to_date)s
				or to_date between %(from_date)s and %(to_date)s
				or (from_date < %(from_date)s and to_date > %(to_date)s))
	""", {
		"from_date": from_date,
		"to_date": to_date,
		"company": company
	}, as_dict=1)

	if leave_period:
		return leave_period

def get_payroll_period(from_date, to_date, company):
	payroll_period = frappe.db.sql("""select name, start_date, end_date from
		`tabPayroll Period`
		where start_date<=%s and end_date>= %s and company=%s""", (from_date, to_date, company), as_dict=1)
	return payroll_period[0] if payroll_period else None

def allocate_earned_leaves():
	'''Allocate earned leaves to Employees'''
	e_leave_types = frappe.get_all("Leave Type",
		fields=["name", "max_leaves_allowed", "earned_leave_frequency", "rounding"],
		filters={'is_earned_leave' : 1})
	today = getdate()
	divide_by_frequency = {"Yearly": 1, "Quarterly": 4, "Monthly": 12}
	if e_leave_types:
		for e_leave_type in e_leave_types:
			leave_allocations = frappe.db.sql("""select name, employee, from_date, to_date from `tabLeave Allocation` where '{0}'
				between from_date and to_date and docstatus=1 and leave_type='{1}'"""
				.format(today, e_leave_type.name), as_dict=1)
			for allocation in leave_allocations:
				leave_policy = get_employee_leave_policy(allocation.employee)
				if not leave_policy:
					continue
				if not e_leave_type.earned_leave_frequency == "Monthly":
					if not check_frequency_hit(allocation.from_date, today, e_leave_type.earned_leave_frequency):
						continue
				annual_allocation = frappe.db.sql("""select annual_allocation from `tabLeave Policy Detail`
					where parent=%s and leave_type=%s""", (leave_policy.name, e_leave_type.name))
				if annual_allocation and annual_allocation[0]:
					earned_leaves = flt(annual_allocation[0][0]) / divide_by_frequency[e_leave_type.earned_leave_frequency]
					if e_leave_type.rounding == "0.5":
						earned_leaves = round(earned_leaves * 2) / 2
					else:
						earned_leaves = round(earned_leaves)

					allocated_leaves = frappe.db.get_value('Leave Allocation', allocation.name, 'total_leaves_allocated')
					new_allocation = flt(allocated_leaves) + flt(earned_leaves)
					new_allocation = new_allocation if new_allocation <= e_leave_type.max_leaves_allowed else e_leave_type.max_leaves_allowed
					frappe.db.set_value('Leave Allocation', allocation.name, 'total_leaves_allocated', new_allocation)

def check_frequency_hit(from_date, to_date, frequency):
	'''Return True if current date matches frequency'''
	from_dt = get_datetime(from_date)
	to_dt = get_datetime(to_date)
	from dateutil import relativedelta
	rd = relativedelta.relativedelta(to_dt, from_dt)
	months = rd.months
	if frequency == "Quarterly":
		if not months % 3:
			return True
	elif frequency == "Yearly":
		if not months % 12:
			return True
	return False

def get_salary_assignment(employee, date):
	assignment = frappe.db.sql("""
		select * from `tabSalary Structure Assignment`
		where employee=%(employee)s
		and docstatus = 1
		and (
			(%(on_date)s between from_date and ifnull(to_date, '2199-12-31'))
		)""", {
			'employee': employee,
			'on_date': date,
		}, as_dict=1)
	return assignment[0] if assignment else None

def calculate_eligible_hra_exemption(company, employee, monthly_house_rent, rented_in_metro_city):
	hra_component = frappe.db.get_value("Company", company, "hra_component")
	annual_exemption, monthly_exemption, hra_amount = 0, 0, 0
	if hra_component:
		assignment = get_salary_assignment(employee, getdate())
		if assignment and frappe.db.exists("Salary Detail", {
			"parent": assignment.salary_structure,
			"salary_component": hra_component, "parentfield": "earnings"}):
			hra_amount = get_hra_from_salary_slip(employee, assignment.salary_structure, hra_component)
			if hra_amount:
				if monthly_house_rent:
					annual_exemption = calculate_hra_exemption(assignment.salary_structure,
					 				assignment.base, hra_amount, monthly_house_rent,
									rented_in_metro_city)
					if annual_exemption > 0:
						monthly_exemption = annual_exemption / 12
					else:
						annual_exemption = 0
	return {"hra_amount": hra_amount, "annual_exemption": annual_exemption, "monthly_exemption": monthly_exemption}

def get_hra_from_salary_slip(employee, salary_structure, hra_component):
	salary_slip = make_salary_slip(salary_structure, employee=employee)
	for earning in salary_slip.earnings:
		if earning.salary_component == hra_component:
			return earning.amount

def calculate_hra_exemption(salary_structure, base, monthly_hra, monthly_house_rent, rented_in_metro_city):
	# TODO make this configurable
	exemptions = []
	frequency = frappe.get_value("Salary Structure", salary_structure, "payroll_frequency")
	# case 1: The actual amount allotted by the employer as the HRA.
	exemptions.append(get_annual_component_pay(frequency, monthly_hra))
	actual_annual_rent = monthly_house_rent * 12
	annual_base = get_annual_component_pay(frequency, base)
	# case 2: Actual rent paid less 10% of the basic salary.
	exemptions.append(flt(actual_annual_rent) - flt(annual_base * 0.1))
	# case 3: 50% of the basic salary, if the employee is staying in a metro city (40% for a non-metro city).
	exemptions.append(annual_base * 0.5 if rented_in_metro_city else annual_base * 0.4)
	# return minimum of 3 cases
	return min(exemptions)

def get_annual_component_pay(frequency, amount):
	if frequency == "Daily":
		return amount * 365
	elif frequency == "Weekly":
		return amount * 52
	elif frequency == "Fortnightly":
		return amount * 26
	elif frequency == "Monthly":
		return amount * 12
	elif frequency == "Bimonthly":
		return amount * 6