using global::BuildFlow.Shared.Domain.Common;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Workflow.Application.Engine;
using Workflow.Domain.Entities;
using Workflow.Domain.Enums;
using Workflow.Domain.Expressions;
using TaskStatus = Workflow.Domain.Enums.TaskStatus;
using InstanceStatus = Workflow.Domain.Enums.InstanceStatus;

namespace BuildFlow.Workflow.Tests.Engine;

using FluentAssertions;
using Xunit;

/// <summary>
/// 依次审批（Sequential）测试：A → B → C 按顺序逐个审，全部通过才推进，任一驳回中断。
/// 这是钉钉式审批流的核心审批方式，区别于会签（同时）/或签（任一）。
/// </summary>
public class SequentialApprovalTests
{
    private readonly WorkflowDbContext _dbContext;
    private readonly ProcessEngine _engine;

    public SequentialApprovalTests()
    {
        var options = new DbContextOptionsBuilder<WorkflowDbContext>()
            .UseInMemoryDatabase(Guid.NewGuid().ToString())
            .Options;
        _dbContext = new WorkflowDbContext(options);

        // InMemory 不跑审计拦截器，手动填充非空审计字段
        _dbContext.SavingChanges += (sender, _) =>
        {
            if (sender is not DbContext ctx) return;
            foreach (var entry in ctx.ChangeTracker.Entries())
            {
                if (entry.Entity is IAuditable a)
                {
                    a.CreatedBy ??= "test";
                    a.UpdatedBy ??= "test";
                }
                if (entry.Entity is IHasOperatorIP o)
                {
                    o.OperatorIP ??= "127.0.0.1";
                }
            }
        };

        _engine = new ProcessEngine(_dbContext, new ServiceCollection().BuildServiceProvider(), new ConditionEvaluator());
    }

    /// <summary>启动依次审批节点：只创建第 0 个审批人的任务，记录完整序列。</summary>
    [Fact]
    public async Task Sequential_Start_CreatesOnlyFirstAssigneeTask()
    {
        var (approvalNode, instance, endNode) = await SetupSequentialFlow(3);

        await _engine.StartAsync(instance);

        var tasks = await _dbContext.WorkflowTasks
            .Where(t => t.NodeId == approvalNode.Id && t.Status == TaskStatus.Pending)
            .ToListAsync();

        // 只建第 0 个任务（区别于会签一次性建 3 个）
        tasks.Should().HaveCount(1);
        tasks[0].SequentialOrder.Should().Be(0);
        tasks[0].SequentialAssignees.Should().NotBeNull("应记录完整序列供逐个推进");
        tasks[0].SequentialAssignees!.Should().Contain("user:");
    }

    /// <summary>依次审批：第 1 个通过后建第 2 个任务，token 不推进。</summary>
    [Fact]
    public async Task Sequential_FirstApproved_CreatesSecondTaskWithoutPropagating()
    {
        var (approvalNode, instance, endNode) = await SetupSequentialFlow(3);

        await _engine.StartAsync(instance);

        var firstTask = await _dbContext.WorkflowTasks
            .FirstAsync(t => t.NodeId == approvalNode.Id && t.Status == TaskStatus.Pending);

        // 第 1 个通过
        await _engine.CompleteTaskAsync(firstTask, TaskResult.Approved);

        // 第 1 个任务已 Approved
        firstTask.Status.Should().Be(TaskStatus.Approved);

        // 新建了第 2 个任务（SequentialOrder=1），仍是 Pending
        var secondTask = await _dbContext.WorkflowTasks
            .SingleOrDefaultAsync(t => t.NodeId == approvalNode.Id && t.SequentialOrder == 1 && t.Status == TaskStatus.Pending);
        secondTask.Should().NotBeNull("应创建下一个审批人任务");
        secondTask!.SequentialAssignees.Should().Be(firstTask.SequentialAssignees);

        // token 未推进到 End
        var endTokens = await _dbContext.WorkflowTokens.CountAsync(t => t.NodeId == endNode.Id);
        endTokens.Should().Be(0, "依次审批未完成，token 不应到达 End");
    }

    /// <summary>依次审批：全部通过后推进到下游 End。</summary>
    [Fact]
    public async Task Sequential_AllApproved_PropagatesDownstream()
    {
        var (approvalNode, instance, endNode) = await SetupSequentialFlow(3);

        await _engine.StartAsync(instance);

        // 逐个通过 3 个审批人
        for (var i = 0; i < 3; i++)
        {
            var current = await _dbContext.WorkflowTasks
                .FirstAsync(t => t.NodeId == approvalNode.Id && t.Status == TaskStatus.Pending);
            await _engine.CompleteTaskAsync(current, TaskResult.Approved);
        }

        // 全部通过后 token 推进，实例完成
        instance.Status.Should().Be(InstanceStatus.Completed);
    }

    /// <summary>依次审批：中间任一驳回则中断（走 Rejected 边语义；本测试无 Rejected 边故验证不继续建任务）。</summary>
    [Fact]
    public async Task Sequential_RejectedInMiddle_StopsSequentialChain()
    {
        var user1 = Guid.NewGuid();
        var user2 = Guid.NewGuid();
        var approvalNode = new WorkflowNode
        {
            Id = Guid.NewGuid(),
            NodeType = NodeType.Approval,
            Name = "seq",
            CreatedBy = "test",
            UpdatedBy = "test",
            Config = $$"""{ "approvalMode": "sequential", "assigneeRules": ["user:{{user1}}", "user:{{user2}}"] }""",
        };
        // 提供一条 Rejected 边回到自己（避免 No reject edge 异常），再一条 Normal 边到 End
        var startNode = CreateNode(NodeType.Start);
        var endNode = CreateNode(NodeType.End);
        var edgeStart = CreateEdge(startNode, approvalNode);
        var edgeReject = CreateEdge(approvalNode, approvalNode);
        edgeReject.EdgeType = EdgeType.Rejected;
        var edgeApprove = CreateEdge(approvalNode, endNode);

        var (_, instance) = PersistSetup([startNode, approvalNode, endNode], [edgeStart, edgeReject, edgeApprove]);
        await _engine.StartAsync(instance);

        var firstTask = await _dbContext.WorkflowTasks
            .FirstAsync(t => t.NodeId == approvalNode.Id && t.Status == TaskStatus.Pending);

        // 第 1 个驳回 → 走 Rejected 边，不建第 2 个任务
        await _engine.CompleteTaskAsync(firstTask, TaskResult.Rejected);
        firstTask.Status.Should().Be(TaskStatus.Rejected);

        var secondTask = await _dbContext.WorkflowTasks
            .CountAsync(t => t.NodeId == approvalNode.Id && t.SequentialOrder == 1);
        secondTask.Should().Be(0, "驳回后不应继续依次建任务");
    }

    // ===== Setup helpers（与 MultiApprovalTests 同范式）=====

    private async Task<(WorkflowNode ApprovalNode, WorkflowInstance Instance, WorkflowNode EndNode)> SetupSequentialFlow(int assigneeCount)
    {
        var users = Enumerable.Range(0, assigneeCount).Select(_ => Guid.NewGuid()).ToArray();
        var rules = users.Select(u => $"user:{u}").ToArray();
        var rulesJson = System.Text.Json.JsonSerializer.Serialize(rules);
        var approvalNode = new WorkflowNode
        {
            Id = Guid.NewGuid(),
            NodeType = NodeType.Approval,
            Name = "依次审批",
            CreatedBy = "test",
            UpdatedBy = "test",
            Config = $$"""{ "approvalMode": "sequential", "assigneeRules": {{rulesJson}} }""",
        };
        var startNode = CreateNode(NodeType.Start);
        var endNode = CreateNode(NodeType.End);
        var edgeStart = CreateEdge(startNode, approvalNode);
        var edge = CreateEdge(approvalNode, endNode);

        var (_, instance) = PersistSetup([startNode, approvalNode, endNode], [edgeStart, edge]);
        // PersistSetup 内部已 SaveChanges；返回前 await 无副作用，保持签名一致
        await Task.CompletedTask;
        return (approvalNode, instance, endNode);
    }

    private static WorkflowNode CreateNode(NodeType type) => new()
    {
        Id = Guid.NewGuid(),
        NodeType = type,
        Name = type.ToString().ToLowerInvariant(),
        CreatedBy = "test",
        UpdatedBy = "test",
    };

    private static WorkflowEdge CreateEdge(WorkflowNode source, WorkflowNode target) => new()
    {
        Id = Guid.NewGuid(),
        SourceNodeId = source.Id,
        TargetNodeId = target.Id,
        EdgeType = EdgeType.Normal,
        CreatedBy = "test",
        UpdatedBy = "test",
    };

    private (WorkflowDefinition Definition, WorkflowInstance Instance) PersistSetup(
        List<WorkflowNode> nodes, List<WorkflowEdge> edges)
    {
        var definition = new WorkflowDefinition
        {
            Id = Guid.NewGuid(),
            Name = "seq-test-flow",
            Status = DefinitionStatus.Published,
            CreatedBy = "test",
            UpdatedBy = "test",
        };
        foreach (var n in nodes) { n.DefinitionId = definition.Id; _dbContext.WorkflowNodes.Add(n); }
        foreach (var e in edges) { e.DefinitionId = definition.Id; _dbContext.WorkflowEdges.Add(e); }
        _dbContext.WorkflowDefinitions.Add(definition);
        var instance = new WorkflowInstance
        {
            Id = Guid.NewGuid(),
            DefinitionId = definition.Id,
            Title = "seq-test",
            Status = InstanceStatus.Running,
            Variables = "{}",
            CreatedBy = "test",
            UpdatedBy = "test",
        };
        _dbContext.WorkflowInstances.Add(instance);
        _dbContext.SaveChanges();
        return (definition, instance);
    }
}