"use client";

import * as React from "react";
import { useMemo } from "react";
import * as Popover from "@radix-ui/react-popover";
import { Check, Search } from "lucide-react";

import { cn } from "@/lib/utils";
import { api } from "@/lib/trpc";
import {
  Avatar,
  AvatarFallback,
  AvatarImage,
} from "@/components/ui/avatar";
import { Input } from "@/components/ui/input";

export interface WorkspaceUser {
  id: string;
  name: string;
  avatarUrl?: string | null;
}

/** Internal default for prop comparison only; list comes from `listMembers` when `workspaceId` is set */
const WORKSPACE_USERS: WorkspaceUser[] = [
  { id: "u1", name: "Alice", avatarUrl: null },
  { id: "u2", name: "Bob", avatarUrl: null },
  { id: "u3", name: "Charlie", avatarUrl: null },
  { id: "u4", name: "Diana", avatarUrl: null },
];

function initials(name: string) {
  return name
    .split(/\s+/)
    .map((p) => p[0])
    .join("")
    .slice(0, 2)
    .toUpperCase();
}

export interface AssigneePickerProps {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  assignedIds: string[];
  onToggle: (userId: string) => void;
  users?: WorkspaceUser[];
  workspaceHandle?: string;
  children: React.ReactNode;
  side?: "top" | "right" | "bottom" | "left";
  align?: "start" | "center" | "end";
}

export function AssigneePicker({
  open,
  onOpenChange,
  assignedIds,
  onToggle,
  users = WORKSPACE_USERS,
  workspaceHandle,
  children,
  side = "bottom",
  align = "start",
}: AssigneePickerProps) {
  const { data: members } = api.workspaces.listMembers.useQuery(
    { workspace: workspaceHandle! },
    { enabled: Boolean(workspaceHandle) },
  );

  const resolvedUsers = useMemo(() => {
    if (users && users !== WORKSPACE_USERS) return users;
    if (!members) return [];
    return members.map((m) => ({
      id: m.id,
      name: m.name ?? m.email,
      avatarUrl: m.avatarUrl,
    }));
  }, [users, members]);

  const [q, setQ] = React.useState("");
  const filtered = React.useMemo(() => {
    const s = q.trim().toLowerCase();
    if (!s) return resolvedUsers;
    return resolvedUsers.filter((u) => u.name.toLowerCase().includes(s));
  }, [q, resolvedUsers]);

  React.useEffect(() => {
    if (!open) setQ("");
  }, [open]);

  return (
    <Popover.Root open={open} onOpenChange={onOpenChange}>
      <Popover.Trigger asChild>{children}</Popover.Trigger>
      <Popover.Portal>
        <Popover.Content
          side={side}
          align={align}
          sideOffset={6}
          className={cn(
            "z-50 w-[min(100vw-2rem,280px)] rounded-lg border border-border bg-popover p-0 shadow-lg outline-none",
            "data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0",
            "data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2",
          )}
        >
          <div className="border-b border-border p-2">
            <div className="relative">
              <Search className="pointer-events-none absolute left-2 top-1/2 size-3.5 -translate-y-1/2 text-muted-foreground" />
              <Input
                value={q}
                onChange={(e) => setQ(e.target.value)}
                placeholder="Search people…"
                className="h-8 border-0 bg-muted/50 pl-8 text-xs focus-visible:ring-1"
              />
            </div>
          </div>
          <div className="max-h-56 overflow-y-auto p-1">
            {filtered.length === 0 ? (
              <p className="px-2 py-4 text-center text-xs text-muted-foreground">
                No matches
              </p>
            ) : (
              filtered.map((user) => {
                const assigned = assignedIds.includes(user.id);
                return (
                  <button
                    key={user.id}
                    type="button"
                    onClick={() => onToggle(user.id)}
                    className={cn(
                      "flex w-full items-center gap-2 rounded-md px-2 py-1.5 text-left text-xs transition-colors",
                      "hover:bg-accent focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring",
                      assigned && "bg-primary/5",
                    )}
                  >
                    <Avatar className="size-7 border border-border">
                      <AvatarImage src={user.avatarUrl ?? undefined} alt="" />
                      <AvatarFallback className="text-[10px] font-medium">
                        {initials(user.name)}
                      </AvatarFallback>
                    </Avatar>
                    <span className="min-w-0 flex-1 truncate font-medium text-foreground">
                      {user.name}
                    </span>
                    {assigned ? (
                      <Check className="size-4 shrink-0 text-primary" aria-hidden />
                    ) : (
                      <span className="size-4 shrink-0" />
                    )}
                  </button>
                );
              })
            )}
          </div>
        </Popover.Content>
      </Popover.Portal>
    </Popover.Root>
  );
}