import { initTRPC } from "@trpc/server";
import EventEmitter, { on } from "node:events";
import { getConfig } from "./config";
import { errorMessage } from "@/lib/utils/error";
import {
  PublishInputSchema,
  type ProgressEvent,
  type PlatformResult,
  type PublishResult,
} from "./publish.schemas";
import { publishModrinthVersion } from "./platforms/modrinth";
import { publishCurseForgeVersion } from "./platforms/curseforge";
import type { PlatformContext } from "./platforms/types";

// ── tRPC init ──────────────────────────────────────────

const t = initTRPC.create();

// ── Shared EventEmitter for progress ───────────────────

const ee = new EventEmitter();

// ── Platform orchestrator ──────────────────────────────

async function runPlatform(
  platform: "modrinth" | "curseforge",
  mcVersions: { mc_version: string }[],
  ctx: PlatformContext,
): Promise<PlatformResult> {
  const result: PlatformResult = { success: 0, fail: 0, errors: [] };
  const total = mcVersions.length;

  if (total === 0) {
    ee.emit("progress", {
      platform,
      current: 0,
      total: 0,
      status: "completed",
      errors: [],
    } satisfies ProgressEvent);
    return result;
  }

  // Emit initial running state
  ee.emit("progress", {
    platform,
    current: 0,
    total,
    status: "running",
    errors: [],
  } satisfies ProgressEvent);

  const publishFn =
    platform === "modrinth"
      ? publishModrinthVersion
      : publishCurseForgeVersion;

  for (let i = 0; i < mcVersions.length; i++) {
    const { mc_version } = mcVersions[i];

    try {
      await publishFn(ctx, mc_version);
      result.success++;

      const isLast = i + 1 === total;
      ee.emit("progress", {
        platform,
        current: i + 1,
        total,
        status: isLast ? "completed" : "running",
        errors: result.errors,
      } satisfies ProgressEvent);
    } catch (err) {
      result.fail++;
      const msg = `${mc_version}: ${errorMessage(err)}`;
      result.errors.push(msg);

      ee.emit("progress", {
        platform,
        current: i,
        total,
        status: "failed",
        errors: result.errors,
      } satisfies ProgressEvent);

      // Cancel remaining for this platform only
      break;
    }
  }

  return result;
}

// ── Router ─────────────────────────────────────────────

export const appRouter = t.router({
  publish: t.procedure
    .input(PublishInputSchema)
    .mutation(async ({ input }): Promise<PublishResult> => {
      const config = await getConfig(input.configName);

      const ctx: PlatformContext = { input, config };

      const [modrinthSettled, curseforgeSettled] = await Promise.allSettled([
        runPlatform("modrinth", input.mcVersions.modrinth, ctx),
        runPlatform("curseforge", input.mcVersions.curseforge, ctx),
      ]);

      const modrinth: PlatformResult = modrinthSettled.status === "fulfilled"
        ? modrinthSettled.value
        : { success: 0, fail: 0, errors: [errorMessage(modrinthSettled.reason)] };

      const curseforge: PlatformResult = curseforgeSettled.status === "fulfilled"
        ? curseforgeSettled.value
        : { success: 0, fail: 0, errors: [errorMessage(curseforgeSettled.reason)] };

      return { modrinth, curseforge };
    }),

  progress: t.procedure.subscription(async function* (opts) {
    for await (const [data] of on(ee, "progress", {
      signal: opts.signal,
    })) {
      yield data as ProgressEvent;
    }
  }),
});

export type AppRouter = typeof appRouter;