fix: stock analytics report date range issues and add company filter (#27014)

* test: tests for correct get_period_date_ranges

* fix: stock analytics report date range issues

- Upon selecting second half of month with Monthly filter, data from
  that period was missing.
- Solution: "round down" the date as per expected frequency.

* chore: drop py2 and fix misleading docstring

* test: fix test to avoid FY clash

* feat: add company filter in stock analytics report

[skip ci]

Co-authored-by: Marica <maricadsouza221197@gmail.com>
diff --git a/erpnext/stock/report/stock_analytics/stock_analytics.js b/erpnext/stock/report/stock_analytics/stock_analytics.js
index 6b384e2..78afe6d 100644
--- a/erpnext/stock/report/stock_analytics/stock_analytics.js
+++ b/erpnext/stock/report/stock_analytics/stock_analytics.js
@@ -37,11 +37,25 @@
 			default: "",
 		},
 		{
+			fieldname: "company",
+			label: __("Company"),
+			fieldtype: "Link",
+			options: "Company",
+			default: frappe.defaults.get_user_default("Company"),
+			reqd: 1,
+		},
+		{
 			fieldname: "warehouse",
 			label: __("Warehouse"),
 			fieldtype: "Link",
-			options:"Warehouse",
+			options: "Warehouse",
 			default: "",
+			get_query: function() {
+				const company = frappe.query_report.get_filter_value('company');
+				return {
+					filters: { 'company': company }
+				}
+			}
 		},
 		{
 			fieldname: "from_date",
diff --git a/erpnext/stock/report/stock_analytics/stock_analytics.py b/erpnext/stock/report/stock_analytics/stock_analytics.py
index d62abed..a1e1e7f 100644
--- a/erpnext/stock/report/stock_analytics/stock_analytics.py
+++ b/erpnext/stock/report/stock_analytics/stock_analytics.py
@@ -1,14 +1,15 @@
 # Copyright (c) 2013, Frappe Technologies Pvt. Ltd. and contributors
 # For license information, please see license.txt
+import datetime
 
-from __future__ import unicode_literals
 import frappe
 from frappe import _, scrub
-from frappe.utils import getdate, flt
+from frappe.utils import getdate, get_quarter_start, get_first_day_of_week
+from frappe.utils import get_first_day as get_first_day_of_month
+
 from erpnext.stock.report.stock_balance.stock_balance import (get_items, get_stock_ledger_entries, get_item_details)
 from erpnext.accounts.utils import get_fiscal_year
 from erpnext.stock.utils import is_reposting_item_valuation_in_progress
-from six import iteritems
 
 def execute(filters=None):
 	is_reposting_item_valuation_in_progress()
@@ -71,7 +72,8 @@
 
 def get_period_date_ranges(filters):
 		from dateutil.relativedelta import relativedelta
-		from_date, to_date = getdate(filters.from_date), getdate(filters.to_date)
+		from_date = round_down_to_nearest_frequency(filters.from_date, filters.range)
+		to_date = getdate(filters.to_date)
 
 		increment = {
 			"Monthly": 1,
@@ -97,6 +99,31 @@
 
 		return periodic_daterange
 
+
+def round_down_to_nearest_frequency(date: str, frequency: str) -> datetime.datetime:
+	"""Rounds down the date to nearest frequency unit.
+	example:
+
+	>>> round_down_to_nearest_frequency("2021-02-21", "Monthly")
+	datetime.datetime(2021, 2, 1)
+
+	>>> round_down_to_nearest_frequency("2021-08-21", "Yearly")
+	datetime.datetime(2021, 1, 1)
+	"""
+
+	def _get_first_day_of_fiscal_year(date):
+		fiscal_year = get_fiscal_year(date)
+		return fiscal_year and fiscal_year[1] or date
+
+	round_down_function = {
+		"Monthly": get_first_day_of_month,
+		"Quarterly": get_quarter_start,
+		"Weekly": get_first_day_of_week,
+		"Yearly": _get_first_day_of_fiscal_year,
+	}.get(frequency, getdate)
+	return round_down_function(date)
+
+
 def get_period(posting_date, filters):
 	months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
 
@@ -177,7 +204,7 @@
 	periodic_data = get_periodic_data(sle, filters)
 	ranges = get_period_date_ranges(filters)
 
-	for dummy, item_data in iteritems(item_details):
+	for dummy, item_data in item_details.items():
 		row = {
 			"name": item_data.name,
 			"item_name": item_data.item_name,
diff --git a/erpnext/stock/report/stock_analytics/test_stock_analytics.py b/erpnext/stock/report/stock_analytics/test_stock_analytics.py
new file mode 100644
index 0000000..00e268b
--- /dev/null
+++ b/erpnext/stock/report/stock_analytics/test_stock_analytics.py
@@ -0,0 +1,35 @@
+import datetime
+import unittest
+
+from frappe import _dict
+from erpnext.accounts.utils import get_fiscal_year
+
+from erpnext.stock.report.stock_analytics.stock_analytics import get_period_date_ranges
+
+
+class TestStockAnalyticsReport(unittest.TestCase):
+	def test_get_period_date_ranges(self):
+
+		filters = _dict(range="Monthly", from_date="2020-12-28", to_date="2021-02-06")
+
+		ranges = get_period_date_ranges(filters)
+
+		expected_ranges = [
+			[datetime.date(2020, 12, 1), datetime.date(2020, 12, 31)],
+			[datetime.date(2021, 1, 1), datetime.date(2021, 1, 31)],
+			[datetime.date(2021, 2, 1), datetime.date(2021, 2, 6)],
+		]
+
+		self.assertEqual(ranges, expected_ranges)
+
+	def test_get_period_date_ranges_yearly(self):
+
+		filters = _dict(range="Yearly", from_date="2021-01-28", to_date="2021-02-06")
+
+		ranges = get_period_date_ranges(filters)
+		first_date = get_fiscal_year("2021-01-28")[1]
+		expected_ranges = [
+			[first_date, datetime.date(2021, 2, 6)],
+		]
+
+		self.assertEqual(ranges, expected_ranges)