import { OllamaLocalBackend } from "../backends/ollama-local.js";
import { OllamaCloudBackend } from "../backends/ollama-cloud.js";
import { OpencodeBackend } from "../backends/opencode.js";
import { resolveBackend, createBackend } from "../backends/index.js";
import { DEFAULT_BACKEND_CONFIG, BackendUnavailableError } from "../backends/types.js";

describe("Backend Availability Detection", () => {
  describe("OllamaLocalBackend.isAvailable", () => {
    it("returns false for unreachable host", async () => {
      const backend = new OllamaLocalBackend({
        base_url: "http://localhost:1",
        model_profile: "balanced",
      });
      expect(await backend.isAvailable()).toBe(false);
    });

    it("returns false for invalid URL", async () => {
      const backend = new OllamaLocalBackend({
        base_url: "not-a-url",
        model_profile: "balanced",
      });
      expect(await backend.isAvailable()).toBe(false);
    });

    it("returns false for timeout", async () => {
      const backend = new OllamaLocalBackend({
        base_url: "http://192.0.2.1",
        model_profile: "balanced",
      });
      expect(await backend.isAvailable()).toBe(false);
    }, 10000);
  });

  describe("OllamaCloudBackend.isAvailable", () => {
    it("returns false when base_url is empty", async () => {
      const backend = new OllamaCloudBackend({
        base_url: "",
        api_key_env: "OLLAMA_CLOUD_API_KEY",
        model_profile: "quality",
      });
      expect(await backend.isAvailable()).toBe(false);
    });

    it("returns false when no API key in env", async () => {
      const backend = new OllamaCloudBackend({
        base_url: "https://api.example.com",
        api_key_env: "NONEXISTENT_ENV_VAR_12345",
        model_profile: "quality",
        timeout_ms: 5000,
      });
      expect(await backend.isAvailable()).toBe(false);
    });
  });

  describe("OpencodeBackend.isAvailable", () => {
    it("returns false when executable not found", async () => {
      const backend = new OpencodeBackend({
        enabled: true,
        executable: "nonexistent-opencode-binary-xyz",
      });
      expect(await backend.isAvailable()).toBe(false);
    });

    it("returns false when disabled", async () => {
      const backend = new OpencodeBackend({ enabled: false });
      expect(await backend.isAvailable()).toBe(false);
    });
  });

  describe("resolveBackend auto-detection", () => {
    it("throws BackendUnavailableError when no backends available", async () => {
      const config = {
        ...DEFAULT_BACKEND_CONFIG,
        llm_backends: {
          "ollama-local": { base_url: "http://localhost:1", model_profile: "balanced" as const },
          "ollama-cloud": { base_url: "", api_key_env: "NONEXISTENT_12345", model_profile: "quality" as const },
        },
        agent_backends: {
          opencode: { enabled: true, executable: "nonexistent-opencode-binary-xyz" },
        },
      };

      await expect(resolveBackend(config)).rejects.toThrow(BackendUnavailableError);
    });

    it("tries opencode before ollama-local", async () => {
      expect(DEFAULT_BACKEND_CONFIG.provider).toBe("auto");
    });

    it("createBackend throws for unknown provider", () => {
      expect(() => createBackend("unknown-provider" as "opencode", DEFAULT_BACKEND_CONFIG)).toThrow(BackendUnavailableError);
    });
  });

  describe("BackendUnavailableError", () => {
    it("contains installation hints", () => {
      const err = new BackendUnavailableError("auto");
      expect(err.message).toContain("opencode");
      expect(err.message).toContain("OpenAI");
      expect(err.message).toContain("Ollama");
      expect(err.message).toContain("OLLAMA_CLOUD_API_KEY");
    });
  });
});