"use client";

import { useMemo, useState } from "react";
import { Check, ChevronsUpDown } from "lucide-react";
import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from "@/components/ui/dialog";
import { Button } from "@/components/ui/button";
import { Label } from "@/components/ui/label";
import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
import {
  Command,
  CommandEmpty,
  CommandGroup,
  CommandInput,
  CommandItem,
  CommandList,
} from "@/components/ui/command";
import type { ImpersonationUser } from "@/lib/impersonation";
import { cn } from "@/lib/utils";

interface ImpersonationModalProps {
  users: ImpersonationUser[];
  open: boolean;
  onOpenChange: (open: boolean) => void;
  onStart?: () => void;
}

export function ImpersonationModal({ users, open, onOpenChange, onStart }: ImpersonationModalProps) {
  const [userId, setUserId] = useState("");
  const [pickerOpen, setPickerOpen] = useState(false);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const selectedUser = useMemo(
    () => users.find((user) => String(user.id) === userId) ?? null,
    [users, userId],
  );

  async function startImpersonation() {
    if (!userId) return;
    setBusy(true);
    setError(null);
    try {
      const response = await fetch("/api/impersonation/start", {
        method: "POST",
        headers: { "content-type": "application/json" },
        body: JSON.stringify({ userId }),
      });
      const body = await response.json().catch(() => null);
      if (!response.ok) throw new Error(body?.error ?? "Unable to start impersonation.");
      onOpenChange(false);
      onStart?.();
    } catch (e) {
      setError(e instanceof Error ? e.message : "Unable to start impersonation.");
    } finally {
      setBusy(false);
    }
  }

  return (
    <Dialog open={open} onOpenChange={onOpenChange}>
      <DialogContent className="sm:max-w-lg">
        <DialogHeader>
          <DialogTitle>Impersonate a user</DialogTitle>
          <DialogDescription>
            All requests will use the selected user&apos;s identity and permissions until you return to your account.
          </DialogDescription>
        </DialogHeader>
        <div className="flex flex-col gap-4">
          <div>
            <Label htmlFor="impersonation-user">User</Label>
            <Popover open={pickerOpen} onOpenChange={setPickerOpen}>
              <PopoverTrigger asChild>
                <Button
                  id="impersonation-user"
                  variant="outline"
                  role="combobox"
                  aria-expanded={pickerOpen}
                  className="mt-1 w-full justify-between font-normal"
                >
                  {selectedUser
                    ? selectedUser.displayName || selectedUser.username || `User ${selectedUser.id}`
                    : "Select a user"}
                  <ChevronsUpDown className="ml-2 h-4 w-4 shrink-0 opacity-50" />
                </Button>
              </PopoverTrigger>
              <PopoverContent className="w-(--radix-popover-trigger-width) p-0" align="start">
                <Command>
                  <CommandInput placeholder="Search by name or username..." />
                  <CommandList>
                    <CommandEmpty>No users found.</CommandEmpty>
                    <CommandGroup>
                      {users.map((user) => (
                        <CommandItem
                          key={String(user.id)}
                          value={`${user.displayName ?? ""} ${user.username ?? ""}`.trim()}
                          onSelect={() => {
                            setUserId(String(user.id));
                            setPickerOpen(false);
                          }}
                        >
                          <span className="truncate">
                            {user.displayName || user.username || `User ${user.id}`}
                            {user.username ? ` (${user.username})` : ""}
                          </span>
                          <Check
                            className={cn(
                              "ml-auto size-4",
                              String(user.id) === userId ? "opacity-100" : "opacity-0",
                            )}
                          />
                        </CommandItem>
                      ))}
                    </CommandGroup>
                  </CommandList>
                </Command>
              </PopoverContent>
            </Popover>
          </div>
          {error && <p className="text-sm text-destructive">{error}</p>}
          <Button onClick={startImpersonation} disabled={!userId || busy}>
            {busy ? "Starting..." : "Start impersonation"}
          </Button>
        </div>
      </DialogContent>
    </Dialog>
  );
}