import { readFileSync } from "node:fs";
import { join } from "node:path";

import { getAgentDir } from "@earendil-works/pi-coding-agent";

import type { DarkOrLightConfig, LoadedSettings } from "./types.js";

function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}

function readJsonFile(filePath: string): Record<string, unknown> {
  try {
    const parsed = JSON.parse(readFileSync(filePath, "utf-8"));
    return isRecord(parsed) ? parsed : {};
  } catch {
    return {};
  }
}

function normalizeDarkOrLightConfig(value: unknown): DarkOrLightConfig | undefined {
  if (!isRecord(value)) return undefined;

  const dark = typeof value.dark === "string" && value.dark.trim() ? value.dark.trim() : undefined;
  const light = typeof value.light === "string" && value.light.trim() ? value.light.trim() : undefined;
  const defaultMode = value.default === "dark" || value.default === "light" ? value.default : undefined;

  if (!dark && !light && !defaultMode) return undefined;

  return { dark, light, default: defaultMode };
}

function readDarkOrLightConfig(filePath: string): DarkOrLightConfig | undefined {
  const settings = readJsonFile(filePath);
  return normalizeDarkOrLightConfig(settings["dark-or-light"] ?? settings.darkOrLight);
}

export function loadSettings(cwd: string): LoadedSettings {
  const globalSettingsPath = join(getAgentDir(), "settings.json");
  const projectSettingsPath = join(cwd, ".pi", "settings.json");

  const darkOrLight = {
    ...readDarkOrLightConfig(globalSettingsPath),
    ...readDarkOrLightConfig(projectSettingsPath),
  };

  return {
    darkOrLight: Object.keys(darkOrLight).length > 0 ? darkOrLight : undefined,
  };
}