using System.Net;
using System.Net.Http;
using Elfisa.Core;
using Xunit;

namespace Elfisa.Tests;

public class ApiClientTests
{
    private static ApiClient Client(HttpMessageHandler h) => new(h, "https://api.test");

    [Fact]
    public void Url_builds_absolute_paths()
    {
        var c = new ApiClient("https://api.test/");
        Assert.Equal("https://api.test/auth/login", c.Url("/auth/login"));
        Assert.Equal("https://api.test/x/y", c.Url("x/y"));
    }

    [Fact]
    public async Task Login_success_returns_token_and_role()
    {
        var h = new FakeHttpHandler(HttpStatusCode.OK, "{\"token\":\"abc\",\"role\":\"buyer\"}");
        var resp = await Client(h).LoginAsync("u", "p");
        Assert.Equal("abc", resp.Token);
        Assert.Equal("buyer", resp.Role);
    }

    [Fact]
    public async Task Login_401_maps_to_friendly_message()
    {
        var h = new FakeHttpHandler(HttpStatusCode.Unauthorized, "{\"error\":\"x\"}");
        var ex = await Assert.ThrowsAsync<ApiException>(() => Client(h).LoginAsync("u", "p"));
        Assert.Contains("Неверный логин", ex.Message);
    }

    [Fact]
    public async Task Login_429_maps_to_ratelimit_message()
    {
        var h = new FakeHttpHandler((HttpStatusCode)429, "{}");
        var ex = await Assert.ThrowsAsync<ApiException>(() => Client(h).LoginAsync("u", "p"));
        Assert.Contains("Слишком много", ex.Message);
    }

    [Fact]
    public async Task Login_retries_transient_then_succeeds()
    {
        var h = new FakeHttpHandler((req, i) =>
            i < 2 ? throw new HttpRequestException("transient")
                  : FakeHttpHandler.Json(HttpStatusCode.OK, "{\"token\":\"ok\"}"));
        var resp = await Client(h).LoginAsync("u", "p");
        Assert.Equal("ok", resp.Token);
        Assert.Equal(3, h.Calls); // 2 сбоя + 1 успех
    }

    [Fact]
    public async Task Login_gives_up_after_retries()
    {
        var h = new FakeHttpHandler((req, i) => throw new HttpRequestException("down"));
        await Assert.ThrowsAsync<ApiException>(() => Client(h).LoginAsync("u", "p"));
        Assert.Equal(3, h.Calls); // 1 попытка + 2 повтора
    }

    [Fact]
    public async Task Summary_parses_response_and_builds_query()
    {
        var body = "{\"total_drugs\":2,\"summary\":[{\"supplier_price_id\":\"1\",\"drug_name\":\"Аспирин\",\"price\":10.5}]}";
        var h = new FakeHttpHandler(HttpStatusCode.OK, body);
        var c = Client(h);
        c.SetToken("t");
        var resp = await c.GetPriceSummaryAsync("асп", limit: 50, offset: 20);
        Assert.Equal(2, resp.TotalDrugs);
        Assert.Single(resp.Summary!);
        Assert.Equal("Аспирин", resp.Summary![0].DrugName);
        Assert.Equal(10.5m, resp.Summary![0].Price);

        var url = h.LastRequest!.RequestUri!.ToString();
        Assert.Contains("limit=50", url);
        Assert.Contains("offset=20", url);
        Assert.Contains("q=", url);
    }

    [Fact]
    public async Task Summary_short_query_omits_q()
    {
        var h = new FakeHttpHandler(HttpStatusCode.OK, "{\"total_drugs\":0,\"summary\":[]}");
        var c = Client(h);
        c.SetToken("t");
        await c.GetPriceSummaryAsync("a", limit: 10, offset: 0); // 1 символ < 2 → без q
        Assert.DoesNotContain("q=", h.LastRequest!.RequestUri!.ToString());
    }

    [Fact]
    public async Task Authorized_call_without_token_throws()
    {
        var h = new FakeHttpHandler(HttpStatusCode.OK, "{}");
        var c = Client(h); // токен не задан
        await Assert.ThrowsAsync<ApiException>(() => c.GetPriceSummaryAsync("асп"));
    }
}