using System.Text.Json;
using FluentAssertions;
using FreeCode.ApiProviders;
using FreeCode.Core.Models;
using FreeCode.Tests.Unit.Helpers;
using Xunit;

namespace FreeCode.Tests.Unit.ApiProviders;

public sealed class AnthropicProviderTests
{
    [Fact]
    public async Task StreamAsync_ParsesStreamingTextDeltas()
    {
        var response = string.Join("\n\n", [
            "data: {\"type\":\"content_block_start\",\"index\":0,\"content_block\":{\"type\":\"text\",\"text\":\"Hello\"}}",
            "data: {\"type\":\"content_block_delta\",\"index\":0,\"delta\":{\"text\":\" world\"}}",
            "data: {\"type\":\"message_stop\"}"
        ]);
        var handler = new MockHttpHandler(response);
        var provider = new AnthropicProvider(new HttpClient(handler));

        var messages = await provider.StreamAsync(TestHelper.CreateMinimalApiRequest()).ToListAsync();

        messages.Should().ContainEquivalentOf(new SDKMessage.StreamingDelta("Hello"));
        messages.Should().ContainEquivalentOf(new SDKMessage.StreamingDelta(" world"));
    }

    [Fact]
    public async Task StreamAsync_ParsesToolUseBlocks()
    {
        var response = string.Join("\n\n", [
            "data: {\"type\":\"content_block_start\",\"index\":1,\"content_block\":{\"type\":\"tool_use\",\"id\":\"tool-1\",\"name\":\"Read\"}}",
            "data: {\"type\":\"content_block_delta\",\"index\":1,\"delta\":{\"partial_json\":\"{\\\"path\\\":\\\"/tmp/file.txt\\\"}\"}}",
            "data: {\"type\":\"content_block_stop\",\"index\":1}",
            "data: {\"type\":\"message_stop\"}"
        ]);
        var handler = new MockHttpHandler(response);
        var provider = new AnthropicProvider(new HttpClient(handler));

        var messages = await provider.StreamAsync(TestHelper.CreateMinimalApiRequest()).ToListAsync();
        var toolUse = messages.OfType<SDKMessage.ToolUseStart>().Single();

        toolUse.ToolUseId.Should().Be("tool-1");
        toolUse.ToolName.Should().Be("Read");
        toolUse.Input.GetProperty("path").GetString().Should().Be("/tmp/file.txt");
    }

    [Fact]
    public async Task StreamAsync_SendsExpectedHeaders()
    {
        const string apiKey = "test-key";
        Environment.SetEnvironmentVariable("ANTHROPIC_API_KEY", apiKey);
        try
        {
            var handler = new MockHttpHandler("data: {\"type\":\"message_stop\"}");
            var provider = new AnthropicProvider(new HttpClient(handler));

            _ = await provider.StreamAsync(new ApiRequest("prompt", ParseJson("[]"), ParseJson("[]"))).ToListAsync();

            handler.LastRequest.Should().NotBeNull();
            handler.LastRequest!.Headers.GetValues("anthropic-version").Should().Contain("2023-06-01");
            handler.LastRequest.Headers.GetValues("x-api-key").Should().Contain(apiKey);
            handler.LastRequest.Headers.GetValues("authorization").Should().Contain($"Bearer {apiKey}");
        }
        finally
        {
            Environment.SetEnvironmentVariable("ANTHROPIC_API_KEY", null);
        }
    }

    private static JsonElement ParseJson(string json)
    {
        using var document = JsonDocument.Parse(json);
        return document.RootElement.Clone();
    }
}