import fs from "node:fs/promises";
import os from "node:os";
import path from "node:path";

import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import type { ClawdisConfig } from "../config/config.js";

async function withTempHome<T>(fn: (home: string) => Promise<T>): Promise<T> {
  const base = await fs.mkdtemp(path.join(os.tmpdir(), "clawdis-models-"));
  const previousHome = process.env.HOME;
  process.env.HOME = base;
  try {
    return await fn(base);
  } finally {
    process.env.HOME = previousHome;
    await fs.rm(base, { recursive: true, force: true });
  }
}

const MODELS_CONFIG: ClawdisConfig = {
  models: {
    providers: {
      "custom-proxy": {
        baseUrl: "http://localhost:4000/v1",
        apiKey: "TEST_KEY",
        api: "openai-completions",
        models: [
          {
            id: "llama-3.1-8b",
            name: "Llama 3.1 8B (Proxy)",
            api: "openai-completions",
            reasoning: false,
            input: ["text"],
            cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
            contextWindow: 128000,
            maxTokens: 32000,
          },
        ],
      },
    },
  },
};

describe("models config", () => {
  let previousHome: string | undefined;

  beforeEach(() => {
    previousHome = process.env.HOME;
  });

  afterEach(() => {
    process.env.HOME = previousHome;
  });

  it("writes models.json for configured providers", async () => {
    await withTempHome(async () => {
      vi.resetModules();
      const { ensureClawdisModelsJson } = await import("./models-config.js");
      const { resolveClawdisAgentDir } = await import("./agent-paths.js");

      await ensureClawdisModelsJson(MODELS_CONFIG);

      const modelPath = path.join(
        resolveClawdisAgentDir(),
        "models.json",
      );
      const raw = await fs.readFile(modelPath, "utf8");
      const parsed = JSON.parse(raw) as {
        providers: Record<string, { baseUrl?: string }>;
      };

      expect(parsed.providers["custom-proxy"]?.baseUrl).toBe(
        "http://localhost:4000/v1",
      );
    });
  });

  it("merges providers by default", async () => {
    await withTempHome(async () => {
      vi.resetModules();
      const { ensureClawdisModelsJson } = await import("./models-config.js");
      const { resolveClawdisAgentDir } = await import("./agent-paths.js");

      const agentDir = resolveClawdisAgentDir();
      await fs.mkdir(agentDir, { recursive: true });
      await fs.writeFile(
        path.join(agentDir, "models.json"),
        JSON.stringify(
          {
            providers: {
              existing: {
                baseUrl: "http://localhost:1234/v1",
                apiKey: "EXISTING_KEY",
                api: "openai-completions",
                models: [
                  {
                    id: "existing-model",
                    name: "Existing",
                    api: "openai-completions",
                    reasoning: false,
                    input: ["text"],
                    cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
                    contextWindow: 8192,
                    maxTokens: 2048,
                  },
                ],
              },
            },
          },
          null,
          2,
        ),
        "utf8",
      );

      await ensureClawdisModelsJson(MODELS_CONFIG);

      const raw = await fs.readFile(path.join(agentDir, "models.json"), "utf8");
      const parsed = JSON.parse(raw) as {
        providers: Record<string, { baseUrl?: string }>;
      };

      expect(parsed.providers.existing?.baseUrl).toBe(
        "http://localhost:1234/v1",
      );
      expect(parsed.providers["custom-proxy"]?.baseUrl).toBe(
        "http://localhost:4000/v1",
      );
    });
  });
});