import type { NotificationProvider } from "@rakazo/adapter-kit";
import { NUDGES_PER_DAY } from "@rakazo/contracts";
import type { PrismaClient } from "@rakazo/db";
import {
  claimDailyNudge,
  countPushSubscriptions,
  ensureMainConversation,
  isPersonalMainBot,
  loadNotificationPolicy,
} from "@rakazo/db";
import { z } from "zod";

export const NOTIFY_USER_BODY_MAX_LENGTH = 200;
export const NOTIFY_USER_TITLE_MAX_LENGTH = 60;

const NotifyUserArgs = z.object({
  body: z.string().trim().min(1).max(NOTIFY_USER_BODY_MAX_LENGTH),
  title: z.string().trim().max(NOTIFY_USER_TITLE_MAX_LENGTH).optional(),
});

export interface NotifyUserToolContext {
  userId: string;
  spaceId: string;
  runId: string;
  bot: { id: string; name: string; kind: string };
  signal: AbortSignal;
}

export type NotifyUserResult = { error: string } | { sent: true } | { sent: false; reason: string };

/**
 * A nudge from the main bot: a push that opens the main conversation. The user's nudge switch,
 * quiet hours and the daily cap all apply; a held-back nudge is reported, not an error.
 */
export async function notifyUserFromTool(
  deps: { prisma: PrismaClient; notifications?: NotificationProvider },
  context: NotifyUserToolContext,
  rawArgs: Record<string, unknown>,
): Promise<NotifyUserResult> {
  if (
    !(await isPersonalMainBot(deps.prisma, { kind: context.bot.kind, spaceId: context.spaceId }))
  ) {
    return { error: "Only the user's main bot can notify the user." };
  }
  const parsed = NotifyUserArgs.safeParse(rawArgs);
  if (!parsed.success) {
    return {
      error: `Invalid notification: body is required, up to ${NOTIFY_USER_BODY_MAX_LENGTH} characters; title up to ${NOTIFY_USER_TITLE_MAX_LENGTH}.`,
    };
  }
  const { prisma, notifications } = deps;
  if (!notifications) {
    return { sent: false, reason: "Push notifications are not available on this server." };
  }
  const policy = await loadNotificationPolicy(prisma, context.userId);
  if (!policy.nudges) return { sent: false, reason: "The user turned nudges off." };
  if (policy.quiet) return { sent: false, reason: "It is the user's quiet hours." };
  if ((await countPushSubscriptions(prisma, context.userId)) === 0) {
    return { sent: false, reason: "The user has no device with notifications turned on." };
  }
  if (!(await claimDailyNudge(prisma, context.userId, policy.localDate))) {
    return { sent: false, reason: `The daily limit of ${NUDGES_PER_DAY} nudges is reached.` };
  }
  const conversation = await ensureMainConversation(prisma, context.userId);
  try {
    await notifications.send(
      {
        kind: "nudge",
        title: parsed.data.title || context.bot.name,
        body: parsed.data.body,
        botId: context.bot.id,
        threadId: conversation.threadId,
      },
      {
        operationId: `notify_user:${context.runId}`,
        traceId: context.runId,
        spaceId: context.spaceId,
        userId: context.userId,
        botId: context.bot.id,
        runId: context.runId,
        signal: context.signal,
      },
    );
  } catch {
    return { sent: false, reason: "No device accepted the notification." };
  }
  return { sent: true };
}