using Xunit;
using FluentAssertions;
using NSubstitute;
using System;
using System.Text.Json;
using FreeCode.Core.Models;
using FreeCode.Core.Enums;

namespace FreeCode.Tests.Unit.Models;

public sealed class SDKMessageTests
{
    [Fact]
    public void SDKMessage_UserMessageWrapsMessage()
    {
        var message = CreateMessage();

        SDKMessage sdkMessage = new SDKMessage.UserMessage(message);

        sdkMessage.Should().BeOfType<SDKMessage.UserMessage>();
        ((SDKMessage.UserMessage)sdkMessage).Message.Should().BeSameAs(message);
    }

    [Fact]
    public void SDKMessage_AssistantMessageStoresTextAndMessageId()
    {
        var sdkMessage = new SDKMessage.AssistantMessage("hello", "msg-1");

        sdkMessage.Text.Should().Be("hello");
        sdkMessage.MessageId.Should().Be("msg-1");
    }

    [Fact]
    public void SDKMessage_StreamingDeltaStoresText()
    {
        var sdkMessage = new SDKMessage.StreamingDelta("partial");

        sdkMessage.Text.Should().Be("partial");
    }

    [Fact]
    public void SDKMessage_ToolUseStartStoresAllFields()
    {
        var input = ParseJson("{\"path\":\"/tmp\"}");

        var sdkMessage = new SDKMessage.ToolUseStart("tool-use-1", "read", input);

        sdkMessage.ToolUseId.Should().Be("tool-use-1");
        sdkMessage.ToolName.Should().Be("read");
        sdkMessage.Input.GetProperty("path").GetString().Should().Be("/tmp");
    }

    [Fact]
    public void SDKMessage_ToolUseResultStoresAllFields()
    {
        var message = CreateMessage();

        var sdkMessage = new SDKMessage.ToolUseResult("tool-use-1", "ok", true, message);

        sdkMessage.ToolUseId.Should().Be("tool-use-1");
        sdkMessage.Output.Should().Be("ok");
        sdkMessage.ShouldContinue.Should().BeTrue();
        sdkMessage.Message.Should().BeSameAs(message);
    }

    [Fact]
    public void SDKMessage_CompactBoundaryStoresReason()
    {
        var sdkMessage = new SDKMessage.CompactBoundary("token_limit");

        sdkMessage.Reason.Should().Be("token_limit");
    }

    [Fact]
    public void SDKMessage_AssistantErrorStoresError()
    {
        var sdkMessage = new SDKMessage.AssistantError("boom");

        sdkMessage.Error.Should().Be("boom");
    }

    [Fact]
    public void SDKMessage_PermissionDenialStoresFields()
    {
        var sdkMessage = new SDKMessage.PermissionDenial("bash", "tool-use-1");

        sdkMessage.ToolName.Should().Be("bash");
        sdkMessage.ToolUseId.Should().Be("tool-use-1");
    }

    [Fact]
    public void SDKMessage_AssistantMessage_UsesValueEquality()
    {
        var left = new SDKMessage.AssistantMessage("hello", "msg-1");
        var right = new SDKMessage.AssistantMessage("hello", "msg-1");

        left.Should().Be(right);
    }

    [Fact]
    public void SDKMessage_AssistantMessage_IsNotEqualWhenTextDiffers()
    {
        var left = new SDKMessage.AssistantMessage("hello", "msg-1");
        var right = new SDKMessage.AssistantMessage("bye", "msg-1");

        left.Should().NotBe(right);
    }

    [Fact]
    public void SDKMessage_UserMessage_SupportsPatternMatching()
    {
        SDKMessage sdkMessage = new SDKMessage.UserMessage(CreateMessage());

        var matched = sdkMessage is SDKMessage.UserMessage userMessage
            && userMessage.Message.Role == MessageRole.User;

        matched.Should().BeTrue();
    }

    [Fact]
    public void SDKMessage_ToolUseStart_CanStoreEmptyToolName()
    {
        var sdkMessage = new SDKMessage.ToolUseStart("tool-use-1", string.Empty, ParseJson("{}"));

        sdkMessage.ToolName.Should().BeEmpty();
    }

    [Fact]
    public void SDKMessage_ToolUseResult_PreservesFalseContinuationFlag()
    {
        var sdkMessage = new SDKMessage.ToolUseResult("tool-use-1", "output", false, CreateMessage());

        sdkMessage.ShouldContinue.Should().BeFalse();
    }

    [Fact]
    public void SDKMessage_StreamingDelta_AllowsEmptyText()
    {
        var sdkMessage = new SDKMessage.StreamingDelta(string.Empty);

        sdkMessage.Text.Should().BeEmpty();
    }

    [Fact]
    public void SDKMessage_AssistantError_AllowsEmptyErrorText()
    {
        var sdkMessage = new SDKMessage.AssistantError(string.Empty);

        sdkMessage.Error.Should().BeEmpty();
    }

    [Fact]
    public void SDKMessage_CompactBoundary_AllowsEmptyReason()
    {
        var sdkMessage = new SDKMessage.CompactBoundary(string.Empty);

        sdkMessage.Reason.Should().BeEmpty();
    }

    [Fact]
    public void SDKMessage_PermissionDenial_AllowsEmptyFields()
    {
        var sdkMessage = new SDKMessage.PermissionDenial(string.Empty, string.Empty);

        sdkMessage.ToolName.Should().BeEmpty();
        sdkMessage.ToolUseId.Should().BeEmpty();
    }

    [Fact]
    public void SDKMessage_ToolUseStart_InputRemainsObjectJson()
    {
        var sdkMessage = new SDKMessage.ToolUseStart("tool-use-1", "read", ParseJson("{\"path\":\"/repo\"}"));

        sdkMessage.Input.ValueKind.Should().Be(JsonValueKind.Object);
    }

    private static Message CreateMessage()
    {
        return new Message
        {
            MessageId = "msg-1",
            Role = MessageRole.User,
            Content = new object(),
            Timestamp = new DateTime(2026, 4, 6, 10, 0, 0, DateTimeKind.Utc)
        };
    }

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