From a6a145f7121944fba7501c242aa66053ede2d24d Mon Sep 17 00:00:00 2001
From: Sergey Elpashev <elpashevs@bk.ru>
Date: Thu, 3 Apr 2025 16:51:56 +0300
Subject: [PATCH] feat: calendar fixes

---
 src/pages/calendar.tsx | 73 ++++++++++++++++++++++++++++++++----------
 1 file changed, 56 insertions(+), 17 deletions(-)

diff --git a/src/pages/calendar.tsx b/src/pages/calendar.tsx
index 64e3ca4..ae58944 100644
--- a/src/pages/calendar.tsx
+++ b/src/pages/calendar.tsx
@@ -1,3 +1,4 @@
+import { cn } from "@/utils/class-merge";
 import { FunctionComponent, h } from "preact";
 import { useState } from "preact/hooks";
 
@@ -11,7 +12,7 @@ interface BigCalendarProps {
 }
 
 const BigCalendar: FunctionComponent<BigCalendarProps> = ({
-  onDateSelect,
+  onDateSelect = () => {},
   markedDates = {},
   className = "",
 }: BigCalendarProps) => {
@@ -33,14 +34,15 @@ const BigCalendar: FunctionComponent<BigCalendarProps> = ({
     "Декабрь",
   ];
 
-  const dayNames: string[] = ["Вс", "Пн", "Вт", "Ср", "Чт", "Пт", "Сб"];
+  const dayNames: string[] = ["Пн", "Вт", "Ср", "Чт", "Пт", "Сб", "Вс"];
 
   const getDaysInMonth = (year: number, month: number): number => {
     return new Date(year, month + 1, 0).getDate();
   };
 
   const getFirstDayOfMonth = (year: number, month: number): number => {
-    return new Date(year, month, 1).getDay();
+    const day = new Date(year, month, 1).getDay();
+    return day === 0 ? 6 : day - 1;
   };
 
   const handlePrevMonth = (): void => {
@@ -64,21 +66,28 @@ const BigCalendar: FunctionComponent<BigCalendarProps> = ({
     return markedDates[dateStr];
   };
 
+  const getLastDayOfMonth = (year: number, month: number): number => {
+    const day = new Date(year, month + 1, 0).getDay();
+    return day === 0 ? 6 : day - 1;
+  };
+
   const renderDays = (): h.JSX.Element[] => {
     const year: number = currentDate.getFullYear();
     const month: number = currentDate.getMonth();
 
     const daysInMonth: number = getDaysInMonth(year, month);
     const firstDayOfMonth: number = getFirstDayOfMonth(year, month);
-    const lastDayOfMonth: number = new Date(year, month, daysInMonth).getDay();
+    const lastDayOfMonth: number = getLastDayOfMonth(year, month);
 
     const days: h.JSX.Element[] = [];
 
     // Дни предыдущего месяца
+    //TODO: work on click on 31 march
     const prevMonthDays = getDaysInMonth(year, month - 1);
-    for (let i = firstDayOfMonth - 1; i >= 0; i--) {
+    const daysFromPrevMonth = firstDayOfMonth === 0 ? 6 : firstDayOfMonth;
+    for (let i = daysFromPrevMonth - 1; i >= 0; i--) {
       const day = prevMonthDays - i;
-      const date = new Date(year, month - 1, day);
+      const date = new Date(year, month - 1, day + 1);
       const dateStr = date.toISOString().split("T")[0];
       const isSelected = selectedDate?.toISOString().split("T")[0] === dateStr;
       const markType = isDateMarked(date);
@@ -86,13 +95,21 @@ const BigCalendar: FunctionComponent<BigCalendarProps> = ({
       days.push(
         <div
           key={`prev-${day}`}
-          className={`relative flex h-24 cursor-pointer flex-col border border-gray-200 p-2 opacity-50 hover:opacity-70 ${isSelected ? "bg-gray-200" : ""} `}
+          className={cn(
+            "relative flex h-24 cursor-pointer flex-col border border-gray-200 p-2 opacity-50 hover:opacity-70",
+            { "bg-gray-200": isSelected }
+          )}
           onClick={() => handleDateClick(date, false)}
         >
           <div className="flex h-8 w-8 items-center justify-center self-end rounded-full text-gray-600">{day}</div>
           {markType && (
             <div
-              className={`mb-1 truncate rounded p-1 text-xs ${markType === "event" ? "bg-green-100 text-green-800" : ""} ${markType === "holiday" ? "bg-red-100 text-red-800" : ""} ${markType === "important" ? "bg-yellow-100 text-yellow-800" : ""} `}
+              className={cn(
+                "mb-1 truncate rounded p-1 text-xs",
+                { "bg-green-100 text-green-800": markType === "event" },
+                { "bg-red-100 text-red-800": markType === "holiday" },
+                { "bg-yellow-100 text-yellow-800": markType === "important" }
+              )}
             >
               {markType}
             </div>
@@ -103,7 +120,7 @@ const BigCalendar: FunctionComponent<BigCalendarProps> = ({
 
     // Дни текущего месяца
     for (let day = 1; day <= daysInMonth; day++) {
-      const date = new Date(year, month, day);
+      const date = new Date(year, month, day + 1);
       const dateStr = date.toISOString().split("T")[0];
       const isSelected = selectedDate?.toISOString().split("T")[0] === dateStr;
       const markType = isDateMarked(date);
@@ -112,18 +129,32 @@ const BigCalendar: FunctionComponent<BigCalendarProps> = ({
       days.push(
         <div
           key={`current-${day}`}
-          className={`relative flex h-24 flex-col border border-gray-200 p-2 ${isSelected ? "border-blue-400 bg-blue-100" : ""} ${isToday ? "border-yellow-400" : ""} cursor-pointer hover:bg-gray-50`}
-          onClick={() => handleDateClick(date, true)}
+          className={cn(
+            "relative flex h-24 flex-col border border-gray-200 p-2",
+            { "border-blue-400 bg-blue-100": isSelected },
+            { "border-yellow-400": isToday },
+            "cursor-pointer hover:bg-gray-50"
+          )}
+          onClick={() => (selectedDate ? setSelectedDate(null) : handleDateClick(date, true))}
         >
           <div
-            className={`flex h-8 w-8 items-center justify-center self-end rounded-full ${isSelected ? "bg-blue-600 text-white" : ""} ${isToday && !isSelected ? "bg-yellow-100 text-yellow-800" : ""} `}
+            className={cn(
+              "flex h-8 w-8 items-center justify-center self-end rounded-full",
+              { "bg-blue-600 text-white": isSelected },
+              { "bg-yellow-100 text-yellow-800": isToday && !isSelected }
+            )}
           >
             {day}
           </div>
 
           {markType && (
             <div
-              className={`mb-1 truncate rounded p-1 text-xs ${markType === "event" ? "bg-green-100 text-green-800" : ""} ${markType === "holiday" ? "bg-red-100 text-red-800" : ""} ${markType === "important" ? "bg-yellow-100 text-yellow-800" : ""} `}
+              className={cn(
+                "mb-1 truncate rounded p-1 text-xs",
+                { "bg-green-100 text-green-800": markType === "event" },
+                { "bg-red-100 text-red-800": markType === "holiday" },
+                { "bg-yellow-100 text-yellow-800": markType === "important" }
+              )}
             >
               {markType}
             </div>
@@ -133,9 +164,9 @@ const BigCalendar: FunctionComponent<BigCalendarProps> = ({
     }
 
     // Дни следующего месяца
-    const daysToAdd = 6 - lastDayOfMonth;
+    const daysToAdd = 6 - (lastDayOfMonth === 6 ? 4 : lastDayOfMonth);
     for (let day = 1; day <= daysToAdd; day++) {
-      const date = new Date(year, month + 1, day);
+      const date = new Date(year, month + 1, day + 1);
       const dateStr = date.toISOString().split("T")[0];
       const isSelected = selectedDate?.toISOString().split("T")[0] === dateStr;
       const markType = isDateMarked(date);
@@ -143,13 +174,21 @@ const BigCalendar: FunctionComponent<BigCalendarProps> = ({
       days.push(
         <div
           key={`next-${day}`}
-          className={`relative flex h-24 cursor-pointer flex-col border border-gray-200 p-2 opacity-50 hover:opacity-70 ${isSelected ? "bg-gray-200" : ""} `}
+          className={cn(
+            "relative flex h-24 cursor-pointer flex-col border border-gray-200 p-2 opacity-50 hover:opacity-70",
+            { "bg-gray-200": isSelected }
+          )}
           onClick={() => handleDateClick(date, false)}
         >
           <div className="flex h-8 w-8 items-center justify-center self-end rounded-full text-gray-600">{day}</div>
           {markType && (
             <div
-              className={`mb-1 truncate rounded p-1 text-xs ${markType === "event" ? "bg-green-100 text-green-800" : ""} ${markType === "holiday" ? "bg-red-100 text-red-800" : ""} ${markType === "important" ? "bg-yellow-100 text-yellow-800" : ""} `}
+              className={cn(
+                "mb-1 truncate rounded p-1 text-xs",
+                { "bg-green-100 text-green-800": markType === "event" },
+                { "bg-red-100 text-red-800": markType === "holiday" },
+                { "bg-yellow-100 text-yellow-800": markType === "important" }
+              )}
             >
               {markType}
             </div>