"use client";

import { useMemo, useState } from "react";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { toast } from "sonner";
import { Button, Card, CardContent, Dialog, Drawer, Input, PageHeader, Select } from "@/components/ds";
import { useMe } from "@/hooks/useMe";
import { useCurrentHub } from "@/modules/workspace/hooks/useCurrentHub";
import { workspaceApi } from "@/modules/workspace/services/workspace-api";
import { KANBAN_COLUMNS, TASK_STATUS, displayPerson, formatDay } from "@/modules/workspace/labels";
import { StatusChip } from "@/modules/workspace/components/StatusChip";
import { IdentityUserSelect } from "@/modules/workspace/components/IdentityUserSelect";
import { CommentThread } from "@/modules/workspace/components/CommentThread";
import { WorkspaceEmptyState, WorkspacePageError, WorkspacePageLoader } from "@/modules/workspace/pages/shared";
import type { WorkspaceRecord } from "@/modules/workspace/types";

export const WorkspaceTasks = function WorkspaceTasksPage() {
  const queryClient = useQueryClient();
  const { me } = useMe();
  const { tenantId, hubId, loading } = useCurrentHub();
  const [open, setOpen] = useState(false);
  const [title, setTitle] = useState("");
  const [projectId, setProjectId] = useState("");
  const [assignee, setAssignee] = useState("");
  const [dueDate, setDueDate] = useState("");
  const [mineOnly, setMineOnly] = useState(false);
  const [selected, setSelected] = useState<WorkspaceRecord | null>(null);
  const [labels, setLabels] = useState("");
  const projects = useQuery({
    queryKey: ["workspace", tenantId, "projects", hubId],
    queryFn: () => workspaceApi.projects.list(tenantId!, { work_hub_id: hubId || undefined }),
    enabled: !!tenantId && !!hubId,
  });
  const tasks = useQuery({
    queryKey: ["workspace", tenantId, "tasks", hubId, mineOnly],
    queryFn: () =>
      workspaceApi.tasks.list(tenantId!, {
        work_hub_id: hubId || undefined,
        assignee_user_id: mineOnly && me?.user_id ? me.user_id : undefined,
      }),
    enabled: !!tenantId && !!hubId,
  });
  const create = useMutation({
    mutationFn: () =>
      workspaceApi.tasks.create(tenantId!, {
        project_id: projectId,
        title,
        assignee_user_id: assignee || undefined,
        due_date: dueDate || undefined,
        labels: labels ? labels.split(",").map((item) => item.trim()).filter(Boolean) : [],
      }),
    onSuccess: () => {
      toast.success("وظیفه ایجاد شد");
      setOpen(false);
      setTitle("");
      void queryClient.invalidateQueries({ queryKey: ["workspace", tenantId, "tasks"] });
    },
    onError: (err) => toast.error(err instanceof Error ? err.message : "ایجاد وظیفه ناموفق بود"),
  });
  const move = useMutation({
    mutationFn: ({ id, status }: { id: string; status: string }) =>
      workspaceApi.tasks.update(tenantId!, id, { status }),
    onSuccess: () => {
      toast.success("وضعیت وظیفه ذخیره شد");
      void queryClient.invalidateQueries({ queryKey: ["workspace", tenantId, "tasks"] });
    },
    onError: (err) => toast.error(err instanceof Error ? err.message : "تغییر وضعیت مجاز نیست"),
  });

  const grouped = useMemo(() => {
    const map: Record<string, WorkspaceRecord[]> = {};
    for (const column of KANBAN_COLUMNS) map[column.id] = [];
    for (const task of tasks.data ?? []) {
      const status = String(task.status || "backlog");
      if (!map[status]) map[status] = [];
      map[status].push(task);
    }
    return map;
  }, [tasks.data]);

  if (!tenantId || loading || tasks.isLoading) return <WorkspacePageLoader />;
  if (!hubId) return <WorkspaceEmptyState title="مرکز کار لازم است" description="ابتدا مرکز کار را انتخاب کنید." />;
  if (tasks.error) return <WorkspacePageError error={tasks.error} onRetry={() => tasks.refetch()} />;

  return (
    <div className="space-y-6">
      <PageHeader
        title="وظایف"
        description="ستون‌های کانبان روی سرور ذخیره می‌شوند. کارت را بکشید تا وضعیت عوض شود."
        actions={
          <div className="flex gap-2">
            <Button variant={mineOnly ? "default" : "outline"} onClick={() => setMineOnly((value) => !value)}>
              وظایف من
            </Button>
            <Button onClick={() => setOpen(true)}>وظیفه جدید</Button>
          </div>
        }
      />
      {(tasks.data ?? []).length === 0 ? (
        <WorkspaceEmptyState
          title="وظیفه‌ای نیست"
          description="یک وظیفه بسازید و آن را بین ستون‌ها جابه‌جا کنید."
          action={<Button onClick={() => setOpen(true)}>ایجاد وظیفه</Button>}
        />
      ) : (
        <div className="grid gap-3 overflow-x-auto pb-4 md:grid-cols-5">
          {KANBAN_COLUMNS.map((column) => (
            <div
              key={column.id}
              className="min-w-[220px] rounded-2xl bg-[var(--surface-muted)] p-3"
              onDragOver={(event) => event.preventDefault()}
              onDrop={(event) => {
                const id = event.dataTransfer.getData("text/task-id");
                if (id) move.mutate({ id, status: column.id });
              }}
            >
              <h2 className="mb-3 text-sm font-semibold text-secondary">{column.label}</h2>
              <div className="space-y-2">
                {(grouped[column.id] ?? []).map((task) => (
                  <Card
                    key={String(task.id)}
                    draggable
                    onDragStart={(event) => event.dataTransfer.setData("text/task-id", String(task.id))}
                    className="cursor-grab"
                    onClick={() => setSelected(task)}
                  >
                    <CardContent className="space-y-2 p-3">
                      <p className="text-sm font-medium">{String(task.title || "وظیفه")}</p>
                      <div className="flex flex-wrap items-center gap-1">
                        <StatusChip value={String(task.priority || "")} kind="priority" />
                        <span className="text-xs text-[var(--muted)]">{displayPerson(String(task.assignee_user_id || ""))}</span>
                      </div>
                      {task.due_date ? (
                        <p className="text-xs text-[var(--muted)]">مهلت {formatDay(String(task.due_date))}</p>
                      ) : null}
                      <Select
                        aria-label="تغییر وضعیت"
                        value={String(task.status || column.id)}
                        onChange={(event) => move.mutate({ id: String(task.id), status: event.target.value })}
                      >
                        {Object.entries(TASK_STATUS)
                          .filter(([value]) => value !== "archived")
                          .map(([value, label]) => (
                            <option key={value} value={value}>
                              {label}
                            </option>
                          ))}
                      </Select>
                    </CardContent>
                  </Card>
                ))}
              </div>
            </div>
          ))}
        </div>
      )}
      <Dialog open={open} onClose={() => setOpen(false)} title="وظیفه جدید">
        <div className="space-y-3">
          <Select value={projectId} onChange={(event) => setProjectId(event.target.value)}>
            <option value="">انتخاب پروژه</option>
            {(projects.data ?? []).map((project) => (
              <option key={String(project.id)} value={String(project.id)}>
                {String(project.name)}
              </option>
            ))}
          </Select>
          <Input value={title} onChange={(event) => setTitle(event.target.value)} placeholder="عنوان وظیفه" />
          <IdentityUserSelect value={assignee} onChange={setAssignee} emptyLabel="مسئول وظیفه" />
          <Input type="date" value={dueDate} onChange={(event) => setDueDate(event.target.value)} />
          <Input value={labels} onChange={(event) => setLabels(event.target.value)} placeholder="برچسب‌ها با ویرگول" />
          <Button className="w-full" disabled={!title.trim() || !projectId || create.isPending} onClick={() => create.mutate()}>
            ایجاد
          </Button>
        </div>
      </Dialog>
      <Drawer open={!!selected} onClose={() => setSelected(null)} title={String(selected?.title || "وظیفه")}>
        {selected && hubId ? (
          <div className="space-y-4">
            <IdentityUserSelect
              value={String(selected.assignee_user_id || "")}
              onChange={(id) => {
                void workspaceApi.tasks.update(tenantId!, String(selected.id), { assignee_user_id: id }).then(() => {
                  toast.success("مسئول ذخیره شد");
                  void queryClient.invalidateQueries({ queryKey: ["workspace", tenantId, "tasks"] });
                });
              }}
              emptyLabel="مسئول"
            />
            <Input
              type="date"
              defaultValue={String(selected.due_date || "").slice(0, 10)}
              onBlur={(event) => {
                void workspaceApi.tasks.update(tenantId!, String(selected.id), { due_date: event.target.value }).then(() => {
                  toast.success("مهلت ذخیره شد");
                  void queryClient.invalidateQueries({ queryKey: ["workspace", tenantId, "tasks"] });
                });
              }}
            />
            <CommentThread tenantId={tenantId!} workHubId={hubId} subjectType="task" subjectId={String(selected.id)} />
          </div>
        ) : null}
      </Drawer>
    </div>
  );
};

export default WorkspaceTasks;