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

namespace BuildFlow.Workflow.Tests.Integration;

/// <summary>
/// 钉钉式审批流全链路端到端测试：树 → 编译 → 图落库读回 → ProcessEngine 启动实例 → 审批完成。
/// 这条链路证明：前端树编辑器产出的树，经 TreeToGraphCompiler 编译后，能被真实 ProcessEngine
/// 加载运行并完成审批。是"钉钉式设计器重做"最权威的运行时验证。
/// </summary>
public class TreeEndToEndTests
{
    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web);

    /// <summary>
    /// 构造一棵"发起人 → 依次审批(A,B) → 结束"的树，编译成图，启动实例，A 通过后建 B，
    /// B 通过后实例完成。
    /// </summary>
    [Fact]
    public async Task Tree_ApprovalChain_RunsThroughEngine_ToCompletion()
    {
        // 1. 构造树
        var userA = Guid.NewGuid();
        var userB = Guid.NewGuid();
        var tree = new
        {
            root = new
            {
                id = Guid.NewGuid().ToString(),
                type = "Initiator",
                config = new { title = "发起人" },
                child = new
                {
                    id = Guid.NewGuid().ToString(),
                    type = "Approval",
                    config = new
                    {
                        title = "依次审批",
                        approvalMode = "sequential",
                        assigneeRules = new[] { $"user:{userA}", $"user:{userB}" },
                    },
                },
            },
        };
        var treeJson = JsonSerializer.Serialize(tree, JsonOptions);

        // 2. 编译成图
        var parsedTree = JsonSerializer.Deserialize<WorkflowTree>(treeJson, JsonOptions)!;
        var compiledGraph = TreeToGraphCompiler.Compile(parsedTree);
        var graphJson = JsonSerializer.Serialize(compiledGraph, JsonOptions);

        // 编译产物必须通过发布校验
        var act = () => WorkflowGraphValidator.Validate(compiledGraph);
        act.Should().NotThrow();

        // 3. 落库（DefinitionJson = 编译产物）并读回，模拟引擎从快照加载
        var options = new DbContextOptionsBuilder<WorkflowDbContext>()
            .UseInMemoryDatabase($"tree-e2e-{Guid.NewGuid()}").Options;
        var db = new WorkflowDbContext(options);
        db.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"; }
            }
        };

        // 引擎 ProcessEngine.LoadGraphAsync 优先读 DefinitionJson（整图 JSON）。
        // 把编译产物作为 WorkflowDefinition.DefinitionJson 存入。
        var definition = new WorkflowDefinition
        {
            Id = Guid.NewGuid(),
            Name = "依次审批流程",
            Code = $"seq-e2e-{Guid.NewGuid():N}",
            Status = DefinitionStatus.Published,
            Version = 1,
            IsEnabled = true,
            DefinitionJson = graphJson,
            DefinitionTree = treeJson,
            CreatedBy = "test",
            UpdatedBy = "test",
        };
        db.WorkflowDefinitions.Add(definition);
        await db.SaveChangesAsync();

        // 4. 启动实例
        var engine = new ProcessEngine(db, new ServiceCollection().BuildServiceProvider(), new ConditionEvaluator());
        var instance = new WorkflowInstance
        {
            Id = Guid.NewGuid(),
            DefinitionId = definition.Id,
            DefinitionCode = definition.Code,
            DefinitionVersion = 1,
            Title = "e2e-instance",
            Status = InstanceStatus.Pending,
            Variables = "{}",
            InitiatorId = Guid.NewGuid(),
            CreatedBy = "test",
            UpdatedBy = "test",
        };
        db.WorkflowInstances.Add(instance);
        await db.SaveChangesAsync();

        await engine.StartAsync(instance);

        // 启动后：依次审批只建 A 的任务（SequentialOrder=0）
        var tasks = await db.WorkflowTasks
            .Where(t => t.Status == TaskStatus.Pending)
            .ToListAsync();
        tasks.Should().HaveCount(1);
        tasks[0].AssigneeId.Should().Be(userA, "依次审批首个任务应分配给 A");
        tasks[0].SequentialOrder.Should().Be(0);

        // 5. A 通过 → 建 B 的任务，实例未完成
        await engine.CompleteTaskAsync(tasks[0], TaskResult.Approved);
        var taskB = await db.WorkflowTasks
            .SingleOrDefaultAsync(t => t.SequentialOrder == 1 && t.Status == TaskStatus.Pending);
        taskB.Should().NotBeNull("A 通过后应建 B 的任务");
        taskB!.AssigneeId.Should().Be(userB);
        instance.Status.Should().NotBe(InstanceStatus.Completed, "B 未审完，实例不应完成");

        // 6. B 通过 → 实例完成（token 到达 End）
        await engine.CompleteTaskAsync(taskB, TaskResult.Approved);
        instance.Status.Should().Be(InstanceStatus.Completed, "依次审批全部通过后实例应完成");
    }
}