import { readFileSync, writeFileSync, mkdirSync } from "node:fs";
import { dirname, join } from "node:path";
import { homedir } from "node:os";
import { getModelById, MODELS } from "./registry/models.js";
import { getTuiById, TUIS } from "./registry/tuis.js";
import type { ModelDef } from "./registry/models.js";
import type { TuiDef } from "./registry/tuis.js";

export interface RuntimeConfig {
  chatModel: string;
  autocompleteModel: string;
  tui: string;
}

const CONFIG_PATH = join(homedir(), ".config", "localcode", "config.json");

const DEFAULTS: RuntimeConfig = {
  chatModel: "gpt-oss",
  autocompleteModel: "qwen-1.5b-autocomplete",
  tui: "aider",
};

export function loadConfig(): RuntimeConfig {
  try {
    const raw = readFileSync(CONFIG_PATH, "utf-8");
    const parsed = JSON.parse(raw) as Partial<RuntimeConfig>;
    return { ...DEFAULTS, ...parsed };
  } catch {
    return { ...DEFAULTS };
  }
}

export function saveConfig(config: RuntimeConfig): void {
  mkdirSync(dirname(CONFIG_PATH), { recursive: true });
  writeFileSync(CONFIG_PATH, JSON.stringify(config, null, 2) + "\n");
}

export function getActiveChatModel(): ModelDef {
  const config = loadConfig();
  return getModelById(config.chatModel) ?? MODELS[0]!;
}

export function getActiveAutocompleteModel(): ModelDef {
  const config = loadConfig();
  return (
    getModelById(config.autocompleteModel) ??
    MODELS.find((m) => m.role === "autocomplete")!
  );
}

export function getActiveTui(): TuiDef {
  const config = loadConfig();
  return getTuiById(config.tui) ?? TUIS[0]!;
}