import ContinueSessionButton from "./continue-session-button";
import useShownSession from "@/src/hooks/use-shown-session";
import conversationHref from "@/src/utils/conversation-href";
import {
    useEffect,
    useState,
    type ComponentProps,
    type ReactNode,
} from "react";
import Input from "@moduletrace/twui/form/Input";
import Modal from "@moduletrace/twui/elements/Modal";
import Button from "@moduletrace/twui/layout/Button";
import H2 from "@moduletrace/twui/layout/H2";
import Row from "@moduletrace/twui/layout/Row";
import Span from "@moduletrace/twui/layout/Span";
import Stack from "@moduletrace/twui/layout/Stack";
import { History, Plus, CircleAlert } from "lucide-react";
import type { BotWithLastMessage } from "@/src/types";
import useBotSessions from "@/src/hooks/use-bot-sessions";
import BotSessionRow from "./bot-session-row";
import HeaderIconButton from "./header-icon-button";
import LoadingBlock from "@moduletrace/twui/elements/LoadingBlock";

type Props = {
    bot: BotWithLastMessage;
    workspace_id?: number | null;
    /**
     * A bot message arrived in another session of this conversation.
     */
    has_other_unread?: boolean;
    /**
     * What opens it; the conversation header's sessions icon by default.
     */
    target?: ReactNode;
    target_wrapper_props?: ComponentProps<typeof Modal>["targetWrapperProps"];
    /**
     * Runs as it opens, e.g. closing the menu it was opened from.
     */
    on_open?: () => void;
};

/**
 * The sessions icon (or another target) that opens a conversation's
 * sessions. A conversation is split into sessions so a bot's context never
 * grows without bound; this lists them, searches them, starts a fresh one,
 * or reopens an old one to carry on.
 */
export default function BotSessionsModal({
    bot,
    workspace_id,
    has_other_unread,
    target,
    target_wrapper_props,
    on_open,
}: Props) {
    const [open, setOpen] = useState(false);
    const on_screen = useShownSession({ bot_id: Number(bot.id), workspace_id });
    const sessions = useBotSessions({
        bot_id: Number(bot.id),
        workspace_id,
        open,
        refresh_key: on_screen ? `${on_screen.id}:${on_screen.status}` : null,
    });
    const name = bot.name || "the bot";

    useEffect(() => {
        if (open) {
            on_open?.();
        }
    }, [open]);

    return (
        <Modal
            target={
                target ?? (
                    <HeaderIconButton
                        icon={History}
                        title={
                            has_other_unread
                                ? "Sessions: new messages in another session"
                                : "Sessions"
                        }
                    />
                )
            }
            targetWrapperProps={
                target_wrapper_props ?? {
                    className: target ? "w-full" : "shrink-0",
                }
            }
            open={open}
            setOpen={setOpen}
            className="max-w-lg bg-paper p-6 xl:p-10 py-14!"
        >
            <Row className="w-full gap-3! flex-nowrap items-start justify-between">
                <Stack className="min-w-0 gap-1! items-stretch">
                    <H2 className="text-lg! leading-6! tracking-normal! font-bold text-ink">
                        Sessions
                    </H2>
                    <Span className="text-[13px] leading-[18px] text-ink-secondary">
                        {`Each session keeps ${name}'s context short. New starts fresh; Continue carries a summary of this one into the next. Reopen any to pick up where you left off.`}
                    </Span>
                </Stack>
                <Row className="shrink-0 gap-2! flex-nowrap items-center">
                    <ContinueSessionButton
                        bot_id={Number(bot.id)}
                        workspace_id={workspace_id}
                    />
                    <Button
                        title="Start a fresh session, without carrying this one over"
                        type="button"
                        size="small"
                        loading={sessions.busy_id == "new"}
                        disabled={Boolean(sessions.busy_id)}
                        onClick={sessions.startSession}
                        className="shrink-0 gap-1!"
                    >
                        <Plus size={14} aria-hidden />
                        New
                    </Button>
                </Row>
            </Row>
            <Input
                id="bot-sessions-search"
                title="Search sessions"
                placeholder="Search titles, summaries and messages"
                autoComplete="off"
                defaultValue={sessions.query}
                onChange={(e) => sessions.setQuery(e.target.value)}
                wrapperWrapperProps={{ className: "mt-4" }}
            />
            {sessions.error ? (
                <Span
                    role="alert"
                    className="mt-2 flex items-center gap-1.5 text-[13px] leading-[18px] text-ink"
                >
                    <CircleAlert size={14} aria-hidden className="shrink-0" />
                    {sessions.error}
                </Span>
            ) : null}
            <Stack className="w-full mt-2 max-h-[60vh] overflow-y-auto gap-0! items-stretch">
                {sessions.sessions.map((session) => (
                    <BotSessionRow
                        key={session.id}
                        session={session}
                        loading={sessions.busy_id == session.id}
                        disabled={Boolean(sessions.busy_id)}
                        current={on_screen?.id ? on_screen.id == session.id : session.status == "active"}
                        onOpen={() =>
                            session.status == "active"
                                ? window.location.assign(conversationHref({ bot_id: Number(bot.id), workspace_id }))
                                : sessions.reopenSession({
                                      session_id: Number(session.id),
                                  })
                        }
                    />
                ))}
                {sessions.loading ? (
                    <LoadingBlock className="w-full h-[300px]" />
                ) : sessions.sessions.length ? (
                    <Span className="px-3 py-6 text-[13px] leading-[18px] text-ink-secondary">
                        {sessions.query.trim()
                            ? `No session matches "${sessions.query.trim()}".`
                            : "No sessions yet."}
                    </Span>
                ) : null}
            </Stack>
        </Modal>
    );
}