import { SolarEdgePortalClient } from "@solar-dash/solaredgeapi";

import { OptimizerDataCache } from "./cache";
import { collectOptimizerData } from "./collector";
import {
  DEFAULT_PORT,
  readAppOptions,
  resolveHomeAssistantTimeZone,
} from "./config";
import { registerHomeAssistantDiscovery } from "./discovery";
import { createRequestHandler } from "./http";

export async function main(): Promise<void> {
  const options = await readAppOptions();
  const timeZone = await resolveHomeAssistantTimeZone();
  const portalClient = new SolarEdgePortalClient({
    username: options.username,
    password: options.password,
    siteId: options.siteId,
  });
  const cache = new OptimizerDataCache({
    pollIntervalMs: options.pollIntervalMinutes * 60_000,
    loadSnapshot: async () => {
      log("info", `Refreshing optimizer data for site ${options.siteId}`);
      const snapshot = await collectOptimizerData({
        reader: portalClient,
        siteId: options.siteId,
        timeZone,
      });
      log(
        snapshot.failedOptimizerCount === 0 ? "info" : "warning",
        `Refresh finished: ${snapshot.successfulOptimizerCount}/${snapshot.optimizerCount} optimizer energy values`,
      );
      return snapshot;
    },
  });
  const port = readPort(process.env.PORT);
  const server = Bun.serve({
    hostname: "0.0.0.0",
    port,
    fetch: createRequestHandler(cache),
  });

  const shutDown = (): void => {
    log("info", "Stopping SolarEdge Optimizer Data App");
    cache.stop();
    void server.stop(true);
  };
  process.once("SIGTERM", shutDown);
  process.once("SIGINT", shutDown);

  log(
    "info",
    `Listening on port ${port}; refresh interval ${options.pollIntervalMinutes} minutes; time zone ${timeZone}`,
  );
  try {
    await registerHomeAssistantDiscovery({ port });
    log("info", "Registered optimizer API discovery with Home Assistant");
  } catch (error) {
    log(
      "warning",
      `Home Assistant discovery registration failed: ${formatStartupError(error)}`,
    );
  }
  cache.start();
}

function readPort(value: string | undefined): number {
  const port = value === undefined ? DEFAULT_PORT : Number(value);
  if (!Number.isInteger(port) || port < 1 || port > 65_535) {
    throw new Error("PORT must be an integer from 1 to 65535");
  }
  return port;
}

function log(level: "info" | "warning" | "error", message: string): void {
  console.log(`${new Date().toISOString()} [${level}] ${message}`);
}

if (import.meta.main) {
  try {
    await main();
  } catch (error) {
    log("error", formatStartupError(error));
    process.exit(1);
  }
}

function formatStartupError(error: unknown): string {
  if (error instanceof Error) {
    return `${error.name}: ${error.message}`;
  }
  return "Unknown startup error";
}