import { describe, it, expect, vi, afterEach } from "vitest";
import {
  NominatimGeocodingProvider,
  GoogleGeocodingProvider,
  resolveGeocodingProvider,
  geocodeBatch,
  type FetchLike,
} from "../services/geocoding.js";

/** Builds a fake fetch returning a single JSON body, recording the called URLs. */
function fakeFetch(
  body: unknown,
  init: { ok?: boolean; status?: number; statusText?: string } = {}
): { fetchImpl: FetchLike; calls: string[] } {
  const calls: string[] = [];
  const fetchImpl: FetchLike = async (url) => {
    calls.push(url);
    return {
      ok: init.ok ?? true,
      status: init.status ?? 200,
      statusText: init.statusText ?? "OK",
      json: async () => body,
    };
  };
  return { fetchImpl, calls };
}

/** Virtual clock whose `sleep` advances `now`, so throttle timing is deterministic. */
function fakeClock() {
  const state = { t: 0 };
  const sleeps: number[] = [];
  return {
    now: () => state.t,
    sleep: async (ms: number) => {
      sleeps.push(ms);
      state.t += ms;
    },
    sleeps,
  };
}

const NOMINATIM_ROW = {
  lat: "40.7128",
  lon: "-74.0060",
  display_name: "New York, NY, USA",
};

describe("NominatimGeocodingProvider", () => {
  it("parses the top match into a GeocodeResult", async () => {
    const { fetchImpl, calls } = fakeFetch([NOMINATIM_ROW]);
    const provider = new NominatimGeocodingProvider({ fetchImpl });

    const result = await provider.geocode("123 Main St");

    expect(result).toEqual({
      latitude: 40.7128,
      longitude: -74.006,
      formattedAddress: "New York, NY, USA",
      provider: "nominatim",
    });
    expect(calls).toHaveLength(1);
    expect(calls[0]).toContain("/search");
    expect(calls[0]).toContain("q=123+Main+St");
    expect(calls[0]).toContain("format=jsonv2");
    expect(calls[0]).toContain("limit=1");
  });

  it("returns null for an empty result set", async () => {
    const { fetchImpl } = fakeFetch([]);
    const provider = new NominatimGeocodingProvider({ fetchImpl });
    expect(await provider.geocode("nowhere at all")).toBeNull();
  });

  it("returns null for a blank address without calling fetch", async () => {
    const { fetchImpl, calls } = fakeFetch([NOMINATIM_ROW]);
    const provider = new NominatimGeocodingProvider({ fetchImpl });
    expect(await provider.geocode("   ")).toBeNull();
    expect(calls).toHaveLength(0);
  });

  it("throws on a non-OK HTTP response", async () => {
    const { fetchImpl } = fakeFetch("rate limited", {
      ok: false,
      status: 429,
      statusText: "Too Many Requests",
    });
    const provider = new NominatimGeocodingProvider({ fetchImpl });
    await expect(provider.geocode("123 Main St")).rejects.toThrow(
      /Nominatim geocoding failed: 429/
    );
  });

  it("sends the configured User-Agent and honors a custom base URL", async () => {
    const calls: Array<{ url: string; headers?: Record<string, string> }> = [];
    const fetchImpl: FetchLike = async (url, opts) => {
      calls.push({ url, headers: opts?.headers });
      return { ok: true, status: 200, statusText: "OK", json: async () => [NOMINATIM_ROW] };
    };
    const provider = new NominatimGeocodingProvider({
      fetchImpl,
      baseUrl: "https://nominatim.example.com/",
      userAgent: "TestAgent/9.9",
    });

    await provider.geocode("123 Main St");

    expect(calls[0]!.url).toContain("https://nominatim.example.com/search");
    expect(calls[0]!.headers?.["User-Agent"]).toBe("TestAgent/9.9");
  });

  it("throttles to ~1 req/sec across consecutive calls (first call not delayed)", async () => {
    const clock = fakeClock();
    const { fetchImpl } = fakeFetch([NOMINATIM_ROW]);
    const provider = new NominatimGeocodingProvider({
      fetchImpl,
      minRequestIntervalMs: 1000,
      now: clock.now,
      sleep: clock.sleep,
    });

    await provider.geocode("a");
    await provider.geocode("b");
    await provider.geocode("c");

    // First request immediate; each subsequent waits the full interval.
    expect(clock.sleeps).toEqual([1000, 1000]);
  });
});

describe("GoogleGeocodingProvider", () => {
  const GOOGLE_OK = {
    status: "OK",
    results: [
      {
        formatted_address: "1600 Amphitheatre Pkwy, Mountain View, CA",
        geometry: { location: { lat: 37.4224, lng: -122.0842 } },
      },
    ],
  };

  it("parses the first result into a GeocodeResult", async () => {
    const { fetchImpl, calls } = fakeFetch(GOOGLE_OK);
    const provider = new GoogleGeocodingProvider("test-key", { fetchImpl });

    const result = await provider.geocode("1600 Amphitheatre Pkwy");

    expect(result).toEqual({
      latitude: 37.4224,
      longitude: -122.0842,
      formattedAddress: "1600 Amphitheatre Pkwy, Mountain View, CA",
      provider: "google",
    });
    expect(calls[0]).toContain("key=test-key");
    expect(calls[0]).toContain("address=1600+Amphitheatre+Pkwy");
  });

  it("returns null on ZERO_RESULTS", async () => {
    const { fetchImpl } = fakeFetch({ status: "ZERO_RESULTS", results: [] });
    const provider = new GoogleGeocodingProvider("test-key", { fetchImpl });
    expect(await provider.geocode("nowhere")).toBeNull();
  });

  it("throws on an API error status with the error message", async () => {
    const { fetchImpl } = fakeFetch({
      status: "REQUEST_DENIED",
      error_message: "The provided API key is invalid.",
    });
    const provider = new GoogleGeocodingProvider("bad-key", { fetchImpl });
    await expect(provider.geocode("123 Main St")).rejects.toThrow(
      /Google geocoding error: REQUEST_DENIED: The provided API key is invalid\./
    );
  });

  it("returns null for a blank address without calling fetch", async () => {
    const { fetchImpl, calls } = fakeFetch(GOOGLE_OK);
    const provider = new GoogleGeocodingProvider("test-key", { fetchImpl });
    expect(await provider.geocode("")).toBeNull();
    expect(calls).toHaveLength(0);
  });

  it("rejects construction with an empty API key", () => {
    expect(() => new GoogleGeocodingProvider("")).toThrow(/non-empty API key/);
  });
});

describe("resolveGeocodingProvider", () => {
  const originalEnv = process.env.GOOGLE_MAPS_API_KEY;
  afterEach(() => {
    if (originalEnv === undefined) delete process.env.GOOGLE_MAPS_API_KEY;
    else process.env.GOOGLE_MAPS_API_KEY = originalEnv;
  });

  it("defaults to Nominatim when provider is unset", () => {
    const provider = resolveGeocodingProvider(null);
    expect(provider.name).toBe("nominatim");
  });

  it("returns Nominatim for an explicit nominatim setting", () => {
    const provider = resolveGeocodingProvider({
      routeOptimizationProvider: "nominatim",
    });
    expect(provider.name).toBe("nominatim");
  });

  it("returns Google and decrypts the stored key when provider is google", () => {
    const decrypt = vi.fn().mockReturnValue("decrypted-google-key");
    const provider = resolveGeocodingProvider(
      { routeOptimizationProvider: "google", googleMapsApiKey: "enc:abc" },
      { decrypt }
    );
    expect(provider.name).toBe("google");
    expect(decrypt).toHaveBeenCalledWith("enc:abc");
  });

  it("falls back to Nominatim (with a warning) when google has no usable key", () => {
    delete process.env.GOOGLE_MAPS_API_KEY;
    const warn = vi.fn();
    const provider = resolveGeocodingProvider(
      { routeOptimizationProvider: "google", googleMapsApiKey: null },
      { warn }
    );
    expect(provider.name).toBe("nominatim");
    expect(warn).toHaveBeenCalledOnce();
  });

  it("falls back to Nominatim (with a warning) when decryption fails", () => {
    const decrypt = vi.fn().mockImplementation(() => {
      throw new Error("bad ciphertext");
    });
    const warn = vi.fn();
    delete process.env.GOOGLE_MAPS_API_KEY;
    const provider = resolveGeocodingProvider(
      { routeOptimizationProvider: "google", googleMapsApiKey: "enc:corrupt" },
      { decrypt, warn }
    );
    expect(provider.name).toBe("nominatim");
    expect(warn).toHaveBeenCalled();
  });

  it("uses GOOGLE_MAPS_API_KEY env var as a fallback key source", () => {
    process.env.GOOGLE_MAPS_API_KEY = "env-key";
    const provider = resolveGeocodingProvider({
      routeOptimizationProvider: "google",
    });
    expect(provider.name).toBe("google");
  });
});

describe("geocodeBatch", () => {
  it("geocodes items in order and preserves keys", async () => {
    const { fetchImpl } = fakeFetch([NOMINATIM_ROW]);
    const provider = new NominatimGeocodingProvider({
      fetchImpl,
      minRequestIntervalMs: 0,
    });

    const outcomes = await geocodeBatch(
      [
        { key: "c1", address: "123 Main St" },
        { key: "c2", address: "456 Oak Ave" },
      ],
      provider
    );

    expect(outcomes.map((o) => o.key)).toEqual(["c1", "c2"]);
    expect(outcomes[0]!.result?.latitude).toBe(40.7128);
    expect(outcomes[1]!.error).toBeUndefined();
  });

  it("captures per-item errors and continues the batch", async () => {
    let call = 0;
    const fetchImpl: FetchLike = async () => {
      call += 1;
      if (call === 1) {
        return { ok: false, status: 500, statusText: "Server Error", json: async () => "" };
      }
      return { ok: true, status: 200, statusText: "OK", json: async () => [NOMINATIM_ROW] };
    };
    const provider = new NominatimGeocodingProvider({ fetchImpl, minRequestIntervalMs: 0 });

    const outcomes = await geocodeBatch(
      [
        { key: 1, address: "bad" },
        { key: 2, address: "good" },
      ],
      provider
    );

    expect(outcomes[0]!.result).toBeNull();
    expect(outcomes[0]!.error).toMatch(/500/);
    expect(outcomes[1]!.result?.latitude).toBe(40.7128);
  });

  it("reports progress for each completed item", async () => {
    const { fetchImpl } = fakeFetch([NOMINATIM_ROW]);
    const provider = new NominatimGeocodingProvider({ fetchImpl, minRequestIntervalMs: 0 });
    const progress: Array<[number, number]> = [];

    await geocodeBatch(
      [
        { key: "a", address: "1 St" },
        { key: "b", address: "2 St" },
      ],
      provider,
      { onProgress: (completed, total) => progress.push([completed, total]) }
    );

    expect(progress).toEqual([
      [1, 2],
      [2, 2],
    ]);
  });
});