"use client";

import type { DragEndEvent, DragStartEvent } from "@dnd-kit/core";
import {
  closestCenter,
  DndContext,
  DragOverlay,
  KeyboardSensor,
  PointerSensor,
  useSensor,
  useSensors,
} from "@dnd-kit/core";
import {
  arrayMove,
  SortableContext,
  sortableKeyboardCoordinates,
  useSortable,
  verticalListSortingStrategy,
} from "@dnd-kit/sortable";
import { CSS } from "@dnd-kit/utilities";
import { Filter, GripVertical, Plus, SortAsc, Star, X } from "lucide-react";
import { useMemo, useState } from "react";

import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { Checkbox } from "@/components/ui/checkbox";
import {
  DropdownMenu,
  DropdownMenuCheckboxItem,
  DropdownMenuContent,
  DropdownMenuLabel,
  DropdownMenuRadioGroup,
  DropdownMenuRadioItem,
  DropdownMenuSeparator,
  DropdownMenuTrigger,
} from "@/components/ui/dropdown-menu";
import { Input } from "@/components/ui/input";
import {
  Item,
  ItemContent,
  ItemGroup,
  ItemMedia,
  ItemTitle,
} from "@/components/ui/item";
import { Separator } from "@/components/ui/separator";
import { cn } from "@/lib/utils";

type Priority = "high" | "medium" | "low";
type SortOption = "manual" | "title" | "priority";

interface Todo {
  id: string;
  title: string;
  completed: boolean;
  priority: Priority;
  starred: boolean;
}

interface Filters {
  starredOnly: boolean;
  priorities: Priority[];
}

interface Todo6Props {
  heading?: string;
  description?: string;
  filterLabel?: string;
  filterByLabel?: string;
  starredOnlyLabel?: string;
  prioritySectionLabel?: string;
  clearFiltersLabel?: string;
  sortLabel?: string;
  sortByLabel?: string;
  manualOrderLabel?: string;
  titleSortLabel?: string;
  prioritySortLabel?: string;
  addTaskLabel?: string;
  taskPlaceholder?: string;
  cancelLabel?: string;
  submitLabel?: string;
  emptyFiltersMessage?: string;
  taskCountLabel?: (count: number) => string;
  priorityLabels?: Record<Priority, string>;
  sortBadges?: Record<SortOption, string>;
  starredAriaLabel?: string;
  initialTodos?: Todo[];
  className?: string;
}

const defaultPriorityLabels: Record<Priority, string> = {
  high: "زیاد",
  medium: "متوسط",
  low: "کم",
};

const defaultSortBadges: Record<SortOption, string> = {
  manual: "د",
  title: "ع",
  priority: "ا",
};

const defaultTodos: Todo[] = [
  {
    id: "1",
    title: "تکمیل مستندات فنی پروژه",
    completed: false,
    priority: "high",
    starred: true,
  },
  {
    id: "2",
    title: "بررسی و تأیید طراحی رابط کاربری",
    completed: false,
    priority: "medium",
    starred: false,
  },
  {
    id: "3",
    title: "آماده‌سازی گزارش هفتگی",
    completed: false,
    priority: "low",
    starred: false,
  },
  {
    id: "4",
    title: "بازبینی کد منابع",
    completed: true,
    priority: "medium",
    starred: false,
  },
  {
    id: "5",
    title: "هماهنگی با تیم طراحی",
    completed: false,
    priority: "high",
    starred: true,
  },
];

interface SortableTodoItemProps {
  todo: Todo;
  onToggle: (id: string) => void;
  priorityLabels: Record<Priority, string>;
  starredAriaLabel: string;
}

const SortableTodoItem = ({
  todo,
  onToggle,
  priorityLabels,
  starredAriaLabel,
}: SortableTodoItemProps) => {
  const {
    attributes,
    listeners,
    setNodeRef,
    transform,
    transition,
    isDragging,
  } = useSortable({ id: todo.id });

  const style = {
    transform: CSS.Translate.toString(transform),
    transition,
    opacity: isDragging ? 0.5 : 1,
  };

  return (
    <div ref={setNodeRef} style={style}>
      <Item
        variant={todo.completed ? "muted" : "default"}
        className={cn(
          "cursor-pointer items-center border-b transition-opacity",
          todo.completed && "opacity-60",
        )}
        onClick={() => onToggle(todo.id)}
      >
        <ItemMedia>
          <div className="flex items-center gap-2">
            <Button
              variant="ghost"
              size="icon-sm"
              {...attributes}
              {...listeners}
              className="cursor-grab active:cursor-grabbing"
              onClick={(e) => e.stopPropagation()}
              aria-label={`جابه‌جایی «${todo.title}»`}
            >
              <GripVertical className="size-4 text-muted-foreground" />
            </Button>
            <Checkbox
              checked={todo.completed}
              onCheckedChange={() => onToggle(todo.id)}
              onClick={(e) => e.stopPropagation()}
              aria-label={
                todo.completed
                  ? `علامت‌گذاری «${todo.title}» به‌عنوان انجام‌نشده`
                  : `علامت‌گذاری «${todo.title}» به‌عنوان انجام‌شده`
              }
            />
          </div>
        </ItemMedia>
        <ItemContent>
          <div className="flex items-center gap-2">
            <ItemTitle
              className={
                todo.completed ? "text-muted-foreground line-through" : ""
              }
            >
              {todo.title}
            </ItemTitle>
            {todo.starred && (
              <Star
                className="size-4 fill-amber-500 text-amber-500"
                aria-label={starredAriaLabel}
              />
            )}
            <Badge variant="outline" className="text-xs">
              {priorityLabels[todo.priority]}
            </Badge>
          </div>
        </ItemContent>
      </Item>
    </div>
  );
};

const Todo6 = ({
  heading = "مدیریت وظایف با فیلتر و مرتب‌سازی",
  description =
    "وظیفه جدید بسازید، بر اساس اولویت و علاقه‌مندی فیلتر کنید و بر اساس عنوان یا اولویت مرتب کنید.",
  filterLabel = "فیلتر",
  filterByLabel = "فیلتر بر اساس",
  starredOnlyLabel = "فقط علاقه‌مندی‌ها",
  prioritySectionLabel = "اولویت",
  clearFiltersLabel = "پاک کردن فیلترها",
  sortLabel = "مرتب‌سازی",
  sortByLabel = "مرتب‌سازی بر اساس",
  manualOrderLabel = "ترتیب دستی",
  titleSortLabel = "عنوان (الف–ی)",
  prioritySortLabel = "اولویت",
  addTaskLabel = "افزودن وظیفه جدید",
  taskPlaceholder = "عنوان وظیفه",
  cancelLabel = "انصراف",
  submitLabel = "افزودن",
  emptyFiltersMessage = "هیچ وظیفه‌ای با فیلترهای شما مطابقت ندارد.",
  taskCountLabel = (count) => `${count} وظیفه`,
  priorityLabels = defaultPriorityLabels,
  sortBadges = defaultSortBadges,
  starredAriaLabel = "علاقه‌مندی",
  initialTodos = defaultTodos,
  className,
}: Todo6Props) => {
  const [todos, setTodos] = useState(initialTodos);
  const [isFormExpanded, setIsFormExpanded] = useState(false);
  const [newTaskTitle, setNewTaskTitle] = useState("");
  const [sortBy, setSortBy] = useState<SortOption>("manual");
  const [filters, setFilters] = useState<Filters>({
    starredOnly: false,
    priorities: [],
  });
  const [activeTodo, setActiveTodo] = useState<Todo | null>(null);

  const sensors = useSensors(
    useSensor(PointerSensor),
    useSensor(KeyboardSensor, {
      coordinateGetter: sortableKeyboardCoordinates,
    }),
  );

  const toggleTodo = (id: string) => {
    setTodos((prevTodos) =>
      prevTodos.map((todo) =>
        todo.id === id ? { ...todo, completed: !todo.completed } : todo,
      ),
    );
  };

  const handleAddTask = () => {
    if (newTaskTitle.trim()) {
      const newTodo: Todo = {
        id: Date.now().toString(),
        title: newTaskTitle.trim(),
        completed: false,
        priority: "medium",
        starred: false,
      };
      setTodos((prevTodos) => [...prevTodos, newTodo]);
      setNewTaskTitle("");
      setIsFormExpanded(false);
    }
  };

  const togglePriorityFilter = (priority: Priority) => {
    setFilters((prev) => ({
      ...prev,
      priorities: prev.priorities.includes(priority)
        ? prev.priorities.filter((p) => p !== priority)
        : [...prev.priorities, priority],
    }));
  };

  const clearFilters = () => {
    setFilters({
      starredOnly: false,
      priorities: [],
    });
  };

  const activeFilterCount =
    (filters.starredOnly ? 1 : 0) + filters.priorities.length;

  const filteredAndSortedTodos = useMemo(() => {
    let filtered = todos.filter((todo) => {
      if (filters.starredOnly && !todo.starred) return false;
      if (
        filters.priorities.length > 0 &&
        !filters.priorities.includes(todo.priority)
      )
        return false;
      return true;
    });

    if (sortBy === "title") {
      filtered = [...filtered].sort((a, b) =>
        a.title.localeCompare(b.title, "fa"),
      );
    } else if (sortBy === "priority") {
      const priorityOrder: Record<Priority, number> = {
        high: 1,
        medium: 2,
        low: 3,
      };
      filtered = [...filtered].sort(
        (a, b) => priorityOrder[a.priority] - priorityOrder[b.priority],
      );
    }

    return filtered;
  }, [todos, filters, sortBy]);

  const handleDragStart = (event: DragStartEvent) => {
    const { active } = event;
    const todo = filteredAndSortedTodos.find((t) => t.id === active.id);
    setActiveTodo(todo || null);
    if (sortBy !== "manual") {
      setSortBy("manual");
    }
  };

  const handleDragEnd = (event: DragEndEvent) => {
    const { active, over } = event;

    if (over && active.id !== over.id) {
      const oldIndex = filteredAndSortedTodos.findIndex(
        (item) => item.id === active.id,
      );
      const newIndex = filteredAndSortedTodos.findIndex(
        (item) => item.id === over.id,
      );

      if (oldIndex !== -1 && newIndex !== -1) {
        const reorderedFiltered = arrayMove(
          filteredAndSortedTodos,
          oldIndex,
          newIndex,
        );
        const reorderedIds = reorderedFiltered.map((t) => t.id);
        setTodos((items) => {
          const sortedItems = [...items].sort((a, b) => {
            const aIndex = reorderedIds.indexOf(a.id);
            const bIndex = reorderedIds.indexOf(b.id);
            if (aIndex === -1) return 1;
            if (bIndex === -1) return -1;
            return aIndex - bIndex;
          });
          return sortedItems;
        });
      }
    }

    setActiveTodo(null);
  };

  return (
    <section dir="rtl" lang="fa" className={cn("py-32", className)}>
      <div className="container">
        <div className="mx-auto flex max-w-2xl flex-col gap-8">
          <div className="flex flex-col gap-2">
            <h2 className="text-3xl font-semibold md:text-xl">{heading}</h2>
            <p className="text-muted-foreground">{description}</p>
          </div>
          <DndContext
            sensors={sensors}
            collisionDetection={closestCenter}
            onDragStart={handleDragStart}
            onDragEnd={handleDragEnd}
          >
            <div className="flex max-w-2xl flex-col gap-4">
              <div className="flex flex-wrap items-center gap-2">
                <DropdownMenu>
                  <DropdownMenuTrigger asChild>
                    <Button variant="outline" size="sm">
                      <Filter className="h-4 w-4" aria-hidden />
                      {filterLabel}
                      {activeFilterCount > 0 && (
                        <Badge variant="secondary" className="px-1.5 py-0">
                          {activeFilterCount}
                        </Badge>
                      )}
                    </Button>
                  </DropdownMenuTrigger>
                  <DropdownMenuContent align="start" className="w-64">
                    <DropdownMenuLabel>{filterByLabel}</DropdownMenuLabel>
                    <DropdownMenuSeparator />
                    <DropdownMenuCheckboxItem
                      checked={filters.starredOnly}
                      onCheckedChange={(checked) =>
                        setFilters((prev) => ({
                          ...prev,
                          starredOnly: checked,
                        }))
                      }
                    >
                      <Star className="h-4 w-4" aria-hidden />
                      {starredOnlyLabel}
                    </DropdownMenuCheckboxItem>
                    <DropdownMenuSeparator />
                    <DropdownMenuLabel className="text-xs">
                      {prioritySectionLabel}
                    </DropdownMenuLabel>
                    <DropdownMenuCheckboxItem
                      checked={filters.priorities.includes("high")}
                      onCheckedChange={() => togglePriorityFilter("high")}
                    >
                      {priorityLabels.high}
                    </DropdownMenuCheckboxItem>
                    <DropdownMenuCheckboxItem
                      checked={filters.priorities.includes("medium")}
                      onCheckedChange={() => togglePriorityFilter("medium")}
                    >
                      {priorityLabels.medium}
                    </DropdownMenuCheckboxItem>
                    <DropdownMenuCheckboxItem
                      checked={filters.priorities.includes("low")}
                      onCheckedChange={() => togglePriorityFilter("low")}
                    >
                      {priorityLabels.low}
                    </DropdownMenuCheckboxItem>
                    {activeFilterCount > 0 && (
                      <>
                        <DropdownMenuSeparator />
                        <Button
                          variant="ghost"
                          size="sm"
                          className="w-full"
                          onClick={clearFilters}
                        >
                          <X className="h-4 w-4" aria-hidden />
                          {clearFiltersLabel}
                        </Button>
                      </>
                    )}
                  </DropdownMenuContent>
                </DropdownMenu>

                <Separator orientation="vertical" className="h-8" />

                <DropdownMenu>
                  <DropdownMenuTrigger asChild>
                    <Button variant="outline" size="sm">
                      <SortAsc className="h-4 w-4" aria-hidden />
                      {sortLabel}
                      <Badge variant="secondary" className="px-1.5 py-0">
                        {sortBadges[sortBy]}
                      </Badge>
                    </Button>
                  </DropdownMenuTrigger>
                  <DropdownMenuContent align="start">
                    <DropdownMenuLabel>{sortByLabel}</DropdownMenuLabel>
                    <DropdownMenuSeparator />
                    <DropdownMenuRadioGroup
                      value={sortBy}
                      onValueChange={(value) => setSortBy(value as SortOption)}
                    >
                      <DropdownMenuRadioItem value="manual">
                        {manualOrderLabel}
                      </DropdownMenuRadioItem>
                      <DropdownMenuRadioItem value="title">
                        {titleSortLabel}
                      </DropdownMenuRadioItem>
                      <DropdownMenuRadioItem value="priority">
                        {prioritySortLabel}
                      </DropdownMenuRadioItem>
                    </DropdownMenuRadioGroup>
                  </DropdownMenuContent>
                </DropdownMenu>

                <div className="ms-auto text-sm text-muted-foreground">
                  {taskCountLabel(filteredAndSortedTodos.length)}
                </div>
              </div>

              {!isFormExpanded ? (
                <Button
                  variant="ghost"
                  size="lg"
                  className="w-full justify-start gap-2"
                  onClick={() => setIsFormExpanded(true)}
                >
                  <Plus className="h-4 w-4" aria-hidden />
                  {addTaskLabel}
                </Button>
              ) : (
                <div className="flex flex-col gap-2 rounded-lg border p-4">
                  <Input
                    autoFocus
                    placeholder={taskPlaceholder}
                    value={newTaskTitle}
                    onChange={(e) => setNewTaskTitle(e.target.value)}
                    onKeyDown={(e) => {
                      if (e.key === "Enter" && newTaskTitle.trim()) {
                        handleAddTask();
                      }
                      if (e.key === "Escape") {
                        setNewTaskTitle("");
                        setIsFormExpanded(false);
                      }
                    }}
                    className="text-base font-medium"
                    aria-label={taskPlaceholder}
                  />
                  <div className="flex items-center justify-end gap-2">
                    <Button
                      variant="secondary"
                      size="sm"
                      onClick={() => {
                        setNewTaskTitle("");
                        setIsFormExpanded(false);
                      }}
                    >
                      <X className="h-4 w-4" aria-hidden />
                      {cancelLabel}
                    </Button>
                    <Button
                      size="sm"
                      onClick={handleAddTask}
                      disabled={!newTaskTitle.trim()}
                    >
                      <Plus className="h-4 w-4" aria-hidden />
                      {submitLabel}
                    </Button>
                  </div>
                </div>
              )}

              <SortableContext
                items={filteredAndSortedTodos.map((t) => t.id)}
                strategy={verticalListSortingStrategy}
              >
                <ItemGroup>
                  {filteredAndSortedTodos.length === 0 ? (
                    <div className="py-8 text-center text-sm text-muted-foreground">
                      {emptyFiltersMessage}
                    </div>
                  ) : (
                    filteredAndSortedTodos.map((todo) => (
                      <SortableTodoItem
                        key={todo.id}
                        todo={todo}
                        onToggle={toggleTodo}
                        priorityLabels={priorityLabels}
                        starredAriaLabel={starredAriaLabel}
                      />
                    ))
                  )}
                </ItemGroup>
              </SortableContext>
            </div>
            <DragOverlay>
              {activeTodo ? (
                <Item
                  variant={activeTodo.completed ? "muted" : "default"}
                  className="cursor-grabbing items-center border-b opacity-90 shadow-lg"
                >
                  <ItemMedia>
                    <div className="flex items-center gap-2">
                      <Button
                        variant="ghost"
                        size="icon-sm"
                        className="cursor-grabbing"
                        aria-hidden
                        tabIndex={-1}
                      >
                        <GripVertical className="size-4 text-muted-foreground" />
                      </Button>
                      <Checkbox
                        checked={activeTodo.completed}
                        aria-hidden
                        tabIndex={-1}
                      />
                    </div>
                  </ItemMedia>
                  <ItemContent>
                    <div className="flex items-center gap-2">
                      <ItemTitle
                        className={
                          activeTodo.completed
                            ? "text-muted-foreground line-through"
                            : ""
                        }
                      >
                        {activeTodo.title}
                      </ItemTitle>
                      {activeTodo.starred && (
                        <Star
                          className="size-4 fill-amber-500 text-amber-500"
                          aria-hidden
                        />
                      )}
                      <Badge variant="outline" className="text-xs">
                        {priorityLabels[activeTodo.priority]}
                      </Badge>
                    </div>
                  </ItemContent>
                </Item>
              ) : null}
            </DragOverlay>
          </DndContext>
        </div>
      </div>
    </section>
  );
};

export { Todo6 };