import { createHash, randomUUID } from "node:crypto";
import type { SupabaseClient } from "@supabase/supabase-js";
import type { Database } from "../shared/database";
import {
  DiscordClient,
  DiscordDeliveryError,
  discordConfiguration,
  discordText,
  type DiscordMessage,
} from "./discord-client";

export const TOURNAMENT_NEWS_CHANNEL = "1558048830770122772";
export const TOURNAMENT_EVENT_ROLES = [
  "1558053709554909205",
  "1558052962817933322",
] as const;
export const TOURNAMENT_ANNOUNCEMENT_LEAD_MS = 15 * 60 * 1000;

export type TournamentAnnouncementSource = {
  id: string;
  name: string;
  owner: string;
  starts_at: string;
  server_timezone: string;
  player_limit: number;
  round_count: number;
  round_time_seconds: number;
  timer_mode: "shared" | "perMini";
  status: string;
  announce_discord: boolean;
};
export type TournamentAnnouncementJob = {
  id: string;
  tournament_id: string;
  state: "pending" | "sending" | "sent" | "skipped" | "failed";
  attempts: number;
  next_attempt_at: string;
  lease_owner: string | null;
  lease_until: string | null;
  channel_id: string | null;
  message_id: string | null;
  sent_at: string | null;
  last_error: string | null;
};

export function tournamentAnnouncementMessage(
  event: string,
  source: TournamentAnnouncementSource,
): DiscordMessage {
  if (!/^[a-zA-Z0-9-]{1,80}$/.test(source.id))
    throw new Error("Invalid tournament link.");
  const timestamp = Date.parse(source.starts_at);
  if (!Number.isFinite(timestamp))
    throw new Error("Invalid tournament start time.");
  const serverTime = new Intl.DateTimeFormat("en-GB", {
    dateStyle: "full",
    timeStyle: "short",
    timeZone: source.server_timezone,
  }).format(timestamp);
  const link = `https://minegeo.site/tournaments/${source.id}`;
  return {
    content: `${TOURNAMENT_EVENT_ROLES.map((role) => `<@&${role}>`).join(", ")}.\n\n## ${discordText(source.name, 120)} will starting soon!\n\nAccess it by this link [${link}](${link})\n\n-------`,
    allowed_mentions: {
      roles: [...TOURNAMENT_EVENT_ROLES],
      users: [],
      replied_user: false,
    },
    nonce: createHash("sha256")
      .update(`tournament:${event}`)
      .digest("hex")
      .slice(0, 24),
    enforce_nonce: true,
    embeds: [
      {
        title: "A community expedition is about to begin!",
        url: link,
        description:
          "Join the lobby before the scheduled start. Play the same locations, climb the final standings, and compete for the champion spotlight on the global leaderboard for seven days.",
        color: 0x55d6ad,
        thumbnail: { url: "https://minegeo.site/images/minegeo-mark.webp" },
        fields: [
          {
            name: "Organizer",
            value: discordText(source.owner, 80),
            inline: true,
          },
          {
            name: "Players",
            value: `Up to ${source.player_limit}`,
            inline: true,
          },
          {
            name: "Format",
            value: `${source.round_count} tournament round${source.round_count === 1 ? "" : "s"} · 5 mini-rounds each`,
            inline: false,
          },
          {
            name: "Round timer",
            value:
              source.timer_mode === "shared"
                ? `${source.round_time_seconds} seconds shared across all 5 mini-rounds`
                : `${source.round_time_seconds} seconds per mini-round`,
            inline: false,
          },
          {
            name: "Starts · server time",
            value: `${serverTime} (${discordText(source.server_timezone, 80)})`,
            inline: false,
          },
          {
            name: "Starts · your local time",
            value: `<t:${Math.floor(timestamp / 1000)}:F> · <t:${Math.floor(timestamp / 1000)}:R>`,
            inline: false,
          },
        ],
        footer: { text: "MineGeo · Community tournaments" },
      },
    ],
  };
}

export async function deliverTournamentAnnouncement(
  job: TournamentAnnouncementJob,
  dependencies: {
    client: Pick<DiscordClient, "send">;
    load: () => Promise<TournamentAnnouncementSource | null>;
    finish: (patch: Partial<TournamentAnnouncementJob>) => Promise<void>;
    now?: () => number;
  },
) {
  const { client, load, finish, now = Date.now } = dependencies;
  const released = { lease_owner: null, lease_until: null };
  try {
    const source = await load();
    if (
      !source ||
      source.id !== job.tournament_id ||
      !source.announce_discord ||
      source.status !== "scheduled" ||
      Date.parse(source.starts_at) <= now()
    ) {
      await finish({ ...released, state: "skipped", last_error: null });
      return;
    }
    const due = Date.parse(source.starts_at) - TOURNAMENT_ANNOUNCEMENT_LEAD_MS;
    // Rescheduling must never produce an early announcement, even with an old lease.
    if (due > now()) {
      await finish({
        ...released,
        state: "pending",
        next_attempt_at: new Date(due).toISOString(),
        last_error: null,
      });
      return;
    }
    const message = await client.send(
      TOURNAMENT_NEWS_CHANNEL,
      tournamentAnnouncementMessage(job.id, source),
    );
    await finish({
      ...released,
      state: "sent",
      channel_id: TOURNAMENT_NEWS_CHANNEL,
      message_id: message,
      sent_at: new Date(now()).toISOString(),
      last_error: null,
    });
  } catch (failure) {
    const error =
      failure instanceof DiscordDeliveryError
        ? failure
        : new DiscordDeliveryError(
            "Tournament announcement could not be confirmed. Delivery will retry.",
          );
    await finish({
      ...released,
      state: error.permanent || job.attempts >= 8 ? "failed" : "pending",
      last_error: error.message,
      next_attempt_at: new Date(
        now() +
          Math.max(
            error.retryAfter,
            Math.min(3600, 30 * 2 ** (job.attempts - 1)),
          ) *
            1000,
      ).toISOString(),
    });
  }
}

export async function dispatchTournamentAnnouncements(
  db: SupabaseClient<Database>,
  env: Record<string, string | undefined> = process.env,
  target?: string,
) {
  const config = discordConfiguration(env);
  if (!config.token) return;
  const worker = randomUUID();
  const claimed = await db
    .rpc("claim_tournament_announcements", {
      p_worker: worker,
      p_target: target ?? null,
    })
    .abortSignal(AbortSignal.timeout(10000));
  if (claimed.error)
    throw new Error("Could not claim saved tournament announcements.");
  const client = new DiscordClient(config.token);
  // Claiming a batch must not make its last job wait through every other send:
  // the durable leases last two minutes; rate-limited sends return to the queue.
  const deliveries = await Promise.allSettled(
    (claimed.data ?? []).map((job) =>
      deliverTournamentAnnouncement(job, {
        client,
        load: async () => {
          const tournament = await db
            .from("tournaments")
            .select(
              "id,name,owner_id,starts_at,server_timezone,player_limit,round_count,round_time_seconds,timer_mode,status,announce_discord",
            )
            .eq("id", job.tournament_id)
            .abortSignal(AbortSignal.timeout(10000))
            .maybeSingle();
          if (tournament.error)
            throw new Error("Could not load tournament announcement.");
          if (!tournament.data) return null;
          const owner = tournament.data.owner_id
            ? await db
                .from("profiles")
                .select("display_name")
                .eq("id", tournament.data.owner_id)
                .abortSignal(AbortSignal.timeout(10000))
                .maybeSingle()
            : { data: null, error: null };
          if (owner.error)
            throw new Error("Could not load tournament organizer.");
          return {
            ...tournament.data,
            owner: owner.data?.display_name ?? "Explorer",
          };
        },
        finish: async (patch) => {
          const result = await db
            .from("tournament_announcements")
            .update(patch)
            .eq("id", job.id)
            .eq("lease_owner", worker)
            .select("id")
            .abortSignal(AbortSignal.timeout(10000))
            .single();
          if (result.error)
            throw new Error("Could not save tournament announcement delivery.");
        },
      }),
    ),
  );
  if (deliveries.some((result) => result.status === "rejected"))
    throw new Error(
      "Some tournament deliveries could not be saved; their leases will expire for retry.",
    );
}