import type { MiddlewareHandler } from "hono";
import type { WebAppEnv } from "../lib/theme-resolution.js";
import { resolveTheme, FALLBACK_THEME } from "../lib/theme-resolution.js";
import { logger } from "../lib/logger.js";

export function createThemeMiddleware(appviewUrl: string): MiddlewareHandler<WebAppEnv> {
  return async (c, next) => {
    const cookieHeader = c.req.header("Cookie");
    const colorSchemeHint = c.req.header("Sec-CH-Prefers-Color-Scheme");
    let theme;
    try {
      theme = await resolveTheme(appviewUrl, cookieHeader, colorSchemeHint);
    } catch (error) {
      logger.error("createThemeMiddleware: resolveTheme threw unexpectedly — using fallback", {
        operation: "createThemeMiddleware",
        error: error instanceof Error ? error.message : String(error),
      });
      theme = FALLBACK_THEME;
    }
    c.set("theme", theme);
    await next();
  };
}