import { initTRPC } from "@trpc/server";
import { z } from "zod";
import EventEmitter, { on } from "node:events";
import { readFileSync } from "node:fs";
import path from "node:path";
import { getConfig } from "./config";
import { modrinthClient, curseforgeClient } from "./clients";
import { createVersion } from "@/lib/modrinth";
import { uploadFile } from "@/lib/curseforge";
import { Template } from "@/lib/utils/template";
import type { CreatableVersion, UploadMetadata } from "@/types";

// ── Zod schemas ────────────────────────────────────────

const PublishInputSchema = z.object({
  configName: z.string(),
  version: z.string(),
  mcVersions: z.object({
    modrinth: z.array(z.object({ mc_version: z.string() })),
    curseforge: z.array(z.object({ mc_version: z.string() })),
  }),
  changelog: z.string(),
  versionType: z.enum(["release", "beta", "alpha"]),
});

const ProgressEventSchema = z.object({
  platform: z.enum(["modrinth", "curseforge"]),
  current: z.number().int().min(0),
  total: z.number().int().min(0),
  status: z.enum(["running", "completed", "failed"]),
  errors: z.array(z.string()),
});

const PlatformResultSchema = z.object({
  success: z.number().int().min(0),
  fail: z.number().int().min(0),
  errors: z.array(z.string()),
});

const PublishResultSchema = z.object({
  modrinth: PlatformResultSchema,
  curseforge: PlatformResultSchema,
});

// ── Inferred types ─────────────────────────────────────

type PublishInput = z.infer<typeof PublishInputSchema>;
type ProgressEvent = z.infer<typeof ProgressEventSchema>;
type PlatformResult = z.infer<typeof PlatformResultSchema>;
type PublishResult = z.infer<typeof PublishResultSchema>;

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

const t = initTRPC.create();

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

const ee = new EventEmitter();

// ── Helpers ────────────────────────────────────────────

function resolveVersionName(
  template: string,
  templates: Record<string, string> | undefined,
  values: Record<string, string>,
): string {
  const tmpl = new Template(template, templates);
  return tmpl.format(values);
}

function buildJarPath(
  projectDir: string,
  format: string,
  version: string,
  mcVersion: string,
): string {
  const tmpl = new Template(format);
  const filename = tmpl.format({ version, mc_version: mcVersion });
  return path.join(projectDir, "build", "libs", filename);
}

function readJarBlob(filePath: string): Blob {
  try {
    const buffer = readFileSync(filePath);
    return new Blob([buffer]);
  } catch (err) {
    const msg = err instanceof Error ? err.message : String(err);
    throw new Error(`Failed to read file "${filePath}": ${msg}`);
  }
}

function errorMessage(err: unknown): string {
  return err instanceof Error ? err.message : String(err);
}

// ── Platform publish logic ─────────────────────────────

interface PlatformContext {
  input: PublishInput;
  config: Awaited<ReturnType<typeof getConfig>>;
}

async function publishModrinthVersion(
  ctx: PlatformContext,
  mcVersion: string,
): Promise<void> {
  const { input, config } = ctx;

  const versionNumber = resolveVersionName(
    config.modrinth.version,
    undefined,
    { version: input.version, mc_version: mcVersion },
  );

  const versionName = resolveVersionName(
    config.modrinth.version_name,
    undefined,
    {
      version: input.version,
      mc_version: mcVersion,
      mc_version_range: mcVersion,
    },
  );

  const primaryPath = buildJarPath(
    config.project_dir,
    config.filename_format,
    input.version,
    mcVersion,
  );
  const sourcePath = buildJarPath(
    config.project_dir,
    config.source_filename_format,
    input.version,
    mcVersion,
  );

  const primaryBlob = readJarBlob(primaryPath);
  const sourceBlob = readJarBlob(sourcePath);

  const data: CreatableVersion = {
    project_id: config.modrinth.project_id,
    name: versionName,
    version_number: versionNumber,
    game_versions: [mcVersion],
    version_type: input.versionType,
    loaders: config.modrinth.loaders,
    featured: false,
    dependencies: config.modrinth.dependencies.map((d) => ({
      version_id: null,
      project_id: d.project_id,
      file_name: null,
      dependency_type: d.dependency_type,
    })),
    file_parts: ["primary", "sources"],
    primary_file: "primary",
    file_types: { sources: "sources-jar" },
    environment: config.modrinth.environment,
  };

  await createVersion(modrinthClient, data, {
    primary: primaryBlob,
    sources: sourceBlob,
  });
}

async function publishCurseForgeVersion(
  ctx: PlatformContext,
  mcVersion: string,
): Promise<void> {
  const { input, config } = ctx;

  const displayName = resolveVersionName(
    config.curseforge.version_name,
    { filename_format: config.filename_format },
    { version: input.version, mc_version: mcVersion },
  );

  const primaryPath = buildJarPath(
    config.project_dir,
    config.filename_format,
    input.version,
    mcVersion,
  );

  const primaryBlob = readJarBlob(primaryPath);

  const metadata: UploadMetadata = {
    changelog: input.changelog,
    changelogType: "markdown",
    displayName,
    releaseType: input.versionType,
    relations: config.curseforge.relations,
  };

  await uploadFile(
    curseforgeClient,
    config.curseforge.project_id,
    metadata,
    primaryBlob,
  );
}

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;