using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging.Abstractions;
using w4c_workflows.Data;
using w4c_workflows.Models;
using w4c_workflows.Models.Nodes;
using w4c_workflows.Services.Credentials;
using w4c_workflows.Services.Nodes;
using w4c_workflows.Services.Nodes.Executors;
using w4c_workflows.Services.Nodes.Interpolation;
using Xunit;

namespace w4c_workflows.Tests;

/// <summary>
/// End-to-end coverage for in-process sub-workflows (<c>core.executeWorkflow</c>):
/// the child run is linked to its parent, output items are mapped back, and the
/// depth/recursion guards stop runaway nesting. Uses the shared Postgres fixture
/// because child-run history is persisted.
/// </summary>
[Collection("WorkflowsPostgres")]
public class SubWorkflowInvokerTests
{
    private readonly WorkflowsPostgresFixture _fixture;

    public SubWorkflowInvokerTests(WorkflowsPostgresFixture fixture)
    {
        _fixture = fixture;
    }

    private static string Tenant() => "t" + Guid.NewGuid().ToString("N")[..12];

    private static NodeWorkflowRunner NewRunner(int maxDepth = SubWorkflowInvoker.DefaultMaxDepth)
    {
        var catalog = NodeTestData.CoreCatalog();
        var executors = new List<INodeExecutor>
        {
            new NoOpNodeExecutor(),
            new SetNodeExecutor(),
            new ExecuteWorkflowNodeExecutor(),
        };
        var graphRunner = new NodeGraphRunner(new NodeExecutorRegistry(executors), new NodeParameterInterpolator());
        var vault = new CredentialVault(new ReversibleTestCipher(), new CredentialTypeCatalog());
        return new NodeWorkflowRunner(catalog, graphRunner, vault, NullLogger<NodeWorkflowRunner>.Instance, maxDepth);
    }

    /// <summary>Child workflow: adds a <c>child</c> marker to each input item.</summary>
    private const string ChildYaml = """
        name: child-transform
        tasks:
          - id: mark
            node: { type: core.set }
            parameters:
              mode: manual
              fields:
                - name: child
                  value: true
        """;

    private static string ParentYaml(string workflow, string extra = "")
        => $$"""
            name: parent-call
            tasks:
              - id: call
                node: { type: core.executeWorkflow }
                parameters:
                  workflow: {{workflow}}
            {{extra}}
            """;

    [Fact]
    public async Task Parent_run_invokes_child_and_maps_its_output()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        var child = WorkflowDataHelpers.CompileAndSave(db, tenant, ChildYaml, "workflows/child.yaml");
        var parent = WorkflowDataHelpers.CompileAndSave(db, tenant, ParentYaml("child-transform"), "workflows/parent.yaml");
        var run = WorkflowDataHelpers.AddPendingRun(db, parent, """[{"n":1},{"n":2}]""");

        var outcome = await NewRunner().RunAsync(db, run, parent, null, default);

        Assert.True(outcome.Succeeded, outcome.Error);
        var output = FlowItemJson.Parse(run.OutputJson);
        Assert.Equal(2, output.Count);
        Assert.All(output, item => Assert.True(item.Json["child"]!.GetValue<bool>()));

        var childRun = await db.WorkflowRuns.SingleAsync(r => r.ParentRunId == run.Id);
        Assert.Equal(child.Id, childRun.WorkflowId);
        Assert.Equal(RunStatus.Succeeded, childRun.Status);
        Assert.Equal(1, childRun.Depth);
        Assert.Equal(WorkflowDataHelpers.TaskByKey(parent, "call").Id, childRun.ParentTaskId);

        var childTaskRuns = await db.TaskRuns.Where(t => t.RunId == childRun.Id).ToListAsync();
        Assert.Single(childTaskRuns);
        Assert.Equal(TaskRunStatus.Succeeded, childTaskRuns[0].Status);
    }

    [Fact]
    public async Task Child_can_be_referenced_by_id()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        var child = WorkflowDataHelpers.CompileAndSave(db, tenant, ChildYaml, "workflows/child.yaml");
        var parent = WorkflowDataHelpers.CompileAndSave(
            db, tenant, ParentYaml(child.Id.ToString()), "workflows/parent-id.yaml");
        var run = WorkflowDataHelpers.AddPendingRun(db, parent, """[{"n":1}]""");

        var outcome = await NewRunner().RunAsync(db, run, parent, null, default);

        Assert.True(outcome.Succeeded, outcome.Error);
        Assert.True(await db.WorkflowRuns.AnyAsync(r => r.ParentRunId == run.Id));
    }

    [Fact]
    public async Task Each_item_mode_starts_one_child_run_per_item()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        WorkflowDataHelpers.CompileAndSave(db, tenant, ChildYaml, "workflows/child.yaml");
        var parent = WorkflowDataHelpers.CompileAndSave(
            db, tenant,
            ParentYaml("child-transform", "      mode: eachItem"),
            "workflows/parent-each.yaml");
        var run = WorkflowDataHelpers.AddPendingRun(db, parent, """[{"n":1},{"n":2},{"n":3}]""");

        var outcome = await NewRunner().RunAsync(db, run, parent, null, default);

        Assert.True(outcome.Succeeded, outcome.Error);
        var childRuns = await db.WorkflowRuns.Where(r => r.ParentRunId == run.Id).ToListAsync();
        Assert.Equal(3, childRuns.Count);
        Assert.All(childRuns, r => Assert.Equal(1, r.Depth));
        Assert.Equal(3, FlowItemJson.Parse(run.OutputJson).Count);
    }

    [Fact]
    public async Task Dropping_history_skips_the_child_task_rows()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        WorkflowDataHelpers.CompileAndSave(db, tenant, ChildYaml, "workflows/child.yaml");
        var parent = WorkflowDataHelpers.CompileAndSave(
            db, tenant,
            ParentYaml("child-transform", "      recordHistory: false"),
            "workflows/parent-nohistory.yaml");
        var run = WorkflowDataHelpers.AddPendingRun(db, parent, """[{"n":1}]""");

        var outcome = await NewRunner().RunAsync(db, run, parent, null, default);

        Assert.True(outcome.Succeeded, outcome.Error);
        var childRun = await db.WorkflowRuns.SingleAsync(r => r.ParentRunId == run.Id);
        Assert.Empty(await db.TaskRuns.Where(t => t.RunId == childRun.Id).ToListAsync());
    }

    [Fact]
    public async Task Not_waiting_runs_the_child_but_emits_no_items()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        WorkflowDataHelpers.CompileAndSave(db, tenant, ChildYaml, "workflows/child.yaml");
        var parent = WorkflowDataHelpers.CompileAndSave(
            db, tenant,
            ParentYaml("child-transform", "      waitForCompletion: false"),
            "workflows/parent-nowait.yaml");
        var run = WorkflowDataHelpers.AddPendingRun(db, parent, """[{"n":1}]""");

        var outcome = await NewRunner().RunAsync(db, run, parent, null, default);

        Assert.True(outcome.Succeeded, outcome.Error);
        Assert.Null(run.OutputJson);
        Assert.True(await db.WorkflowRuns.AnyAsync(r => r.ParentRunId == run.Id));
    }

    [Fact]
    public async Task Recursive_self_call_is_rejected()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        const string selfYaml = """
            name: self-call
            tasks:
              - id: call
                node: { type: core.executeWorkflow }
                parameters:
                  workflow: self-call
            """;
        var self = WorkflowDataHelpers.CompileAndSave(db, tenant, selfYaml, "workflows/self.yaml");
        var run = WorkflowDataHelpers.AddPendingRun(db, self, """[{"n":1}]""");

        var outcome = await NewRunner().RunAsync(db, run, self, null, default);

        Assert.False(outcome.Succeeded);
        Assert.Contains("recursive sub-workflow call", run.Error);
        // The cycle was caught before any child run was created.
        Assert.Empty(await db.WorkflowRuns.Where(r => r.ParentRunId == run.Id).ToListAsync());
    }

    [Fact]
    public async Task Nesting_beyond_the_depth_limit_fails_cleanly()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        WorkflowDataHelpers.CompileAndSave(db, tenant,
            "name: depth-a\ntasks:\n  - id: call\n    node: { type: core.executeWorkflow }\n    parameters:\n      workflow: depth-b\n",
            "workflows/depth-a.yaml");
        WorkflowDataHelpers.CompileAndSave(db, tenant,
            "name: depth-b\ntasks:\n  - id: call\n    node: { type: core.executeWorkflow }\n    parameters:\n      workflow: depth-c\n",
            "workflows/depth-b.yaml");
        WorkflowDataHelpers.CompileAndSave(db, tenant,
            "name: depth-c\ntasks:\n  - id: noop\n    node: { type: core.noop }\n",
            "workflows/depth-c.yaml");

        var a = await db.Workflows.SingleAsync(w => w.Name == "depth-a" && w.TenantId == tenant);
        var run = WorkflowDataHelpers.AddPendingRun(db, a, """[{"n":1}]""");

        var outcome = await NewRunner(maxDepth: 1).RunAsync(db, run, a, null, default);

        Assert.False(outcome.Succeeded);
        Assert.Contains("maximum depth", run.Error);
    }

    [Fact]
    public async Task Unknown_child_workflow_fails_the_run()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        var parent = WorkflowDataHelpers.CompileAndSave(
            db, tenant, ParentYaml("does-not-exist"), "workflows/parent-missing.yaml");
        var run = WorkflowDataHelpers.AddPendingRun(db, parent, """[{"n":1}]""");

        var outcome = await NewRunner().RunAsync(db, run, parent, null, default);

        Assert.False(outcome.Succeeded);
        Assert.Contains("was not found", run.Error);
    }

    [Fact]
    public async Task Uncompiled_child_workflow_fails_the_run()
    {
        var tenant = Tenant();
        await using var db = _fixture.CreateContext();
        db.Workflows.Add(new Workflow
        {
            Id = Guid.NewGuid(),
            TenantId = tenant,
            Name = "broken-child",
            Path = "workflows/broken.yaml",
            Status = WorkflowStatus.Invalid,
            Mode = WorkflowMode.Function,
            Target = "local",
        });
        await db.SaveChangesAsync();

        var parent = WorkflowDataHelpers.CompileAndSave(
            db, tenant, ParentYaml("broken-child"), "workflows/parent-broken.yaml");
        var run = WorkflowDataHelpers.AddPendingRun(db, parent, """[{"n":1}]""");

        var outcome = await NewRunner().RunAsync(db, run, parent, null, default);

        Assert.False(outcome.Succeeded);
        Assert.Contains("is not compiled", run.Error);
    }
}