/** MessagingTab — compose email to Authentik users via the mail queue. */
import { useState } from "react";
import { Alert, AlertDescription } from "@/components/ui/alert";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import {
	useAuthentikUsers,
	useSendAuthentikMessage,
} from "../../hooks/useAuthentik";
import type { ServiceInstance } from "../../types";

const DEFAULT_BODY = "<p>Hello,</p><p> </p><p>Best,<br />Manage</p>";

export function MessagingTab({ instance }: { instance: ServiceInstance }) {
	const [search, setSearch] = useState("");
	const [selectedEmails, setSelectedEmails] = useState<Set<string>>(new Set());
	const [subject, setSubject] = useState("");
	const [htmlBody, setHtmlBody] = useState(DEFAULT_BODY);

	const { data } = useAuthentikUsers(instance.id, {
		search,
		page: 1,
		page_size: 100,
	});
	const sendMessage = useSendAuthentikMessage(instance.id);

	const users = (data?.items ?? []).filter((u) => u.email);
	const error = data?.error;

	function toggleEmail(email: string) {
		setSelectedEmails((prev) => {
			const next = new Set(prev);
			if (next.has(email)) next.delete(email);
			else next.add(email);
			return next;
		});
	}

	function handleSend() {
		if (!subject.trim() || selectedEmails.size === 0) return;
		sendMessage.mutate({
			recipient_emails: Array.from(selectedEmails),
			subject: subject.trim(),
			html_body: htmlBody,
		});
	}

	const canSend =
		subject.trim() !== "" && selectedEmails.size > 0 && !sendMessage.isPending;

	return (
		<div className="flex flex-col gap-4">
			{error ? (
				<Alert variant="destructive">
					<AlertDescription>{error}</AlertDescription>
				</Alert>
			) : null}

			{sendMessage.data ? (
				<Alert>
					<AlertDescription>
						{sendMessage.data.status === "queued"
							? `Message queued (${sendMessage.data.recipient_count ?? 0} recipients, request ${sendMessage.data.request_id?.slice(0, 8) ?? ""}).`
							: `Error: ${sendMessage.data.error ?? "unknown"}`}
					</AlertDescription>
				</Alert>
			) : null}

			<div className="flex flex-col gap-2">
				<Label htmlFor="msg-search">Find recipients</Label>
				<Input
					id="msg-search"
					placeholder="Search users to add as recipients…"
					value={search}
					onChange={(e) => setSearch(e.target.value)}
					className="max-w-md"
				/>
				{users.length > 0 ? (
					<div className="flex flex-wrap gap-2">
						{users.slice(0, 20).map((user) => (
							<Button
								key={user.pk}
								variant={selectedEmails.has(user.email) ? "default" : "outline"}
								size="sm"
								onClick={() => toggleEmail(user.email)}
							>
								{user.name || user.username}
							</Button>
						))}
					</div>
				) : null}
				{selectedEmails.size > 0 ? (
					<p className="text-sm text-muted-foreground">
						{selectedEmails.size} recipient
						{selectedEmails.size === 1 ? "" : "s"} selected.
					</p>
				) : null}
			</div>

			<div className="flex flex-col gap-2">
				<Label htmlFor="msg-subject">Subject</Label>
				<Input
					id="msg-subject"
					value={subject}
					onChange={(e) => setSubject(e.target.value)}
				/>
			</div>

			<div className="flex flex-col gap-2">
				<Label htmlFor="msg-body">Message (HTML)</Label>
				<Textarea
					id="msg-body"
					rows={8}
					value={htmlBody}
					onChange={(e) => setHtmlBody(e.target.value)}
					className="font-mono text-xs"
				/>
			</div>

			<div>
				<Button onClick={handleSend} disabled={!canSend}>
					{sendMessage.isPending ? "Sending…" : "Send message"}
				</Button>
			</div>
		</div>
	);
}