using ClawdDotNet.Core.Tasks;
using Shouldly;

namespace ClawdDotNet.Core.Tests.Tasks;

/// <summary>
/// The frontmatter parser is the bridge between the human/agent-readable
/// task file and the DB state. What it reads wrongly, the board imports wrongly —
/// that's why the round trip is at the center here: serializing and reading back
/// must yield the same definition.
/// </summary>
public sealed class TaskFrontmatterTests
{
    [Fact]
    public void A_complete_frontmatter_is_read()
    {
        var text = """
            ---
            id: t-8f3a2c
            title: NVDA Earnings recherchieren
            status: todo
            type: work
            priority: 4
            assignee: "@crawler"
            when:
              kind: cron
              value: "0 7 * * 1-5"
              tz: Europe/Berlin
            require_approval: true
            acceptance: |
              Aktuelle Zahlen mit Datum und Quelle.
              In SharedWorkspace/data/nvda.json abgelegt.
            blocked_by: [t-4b1e, t-9a2c]
            onlyWhenMarketOpen: false
            ---

            Recherchiere die neuesten Quartalszahlen.
            """;

        TaskFrontmatter.TryParse(text, out var task, out var error).ShouldBeTrue(error);

        task.Id.ShouldBe("t-8f3a2c");
        task.Title.ShouldBe("NVDA Earnings recherchieren");
        task.Status.ShouldBe(TaskItemStatus.Todo);
        task.Type.ShouldBe(TaskItemType.Work);
        task.Priority.ShouldBe(4);
        task.Assignee.ShouldBe("@crawler");
        task.When.ShouldNotBeNull();
        task.When!.Kind.ShouldBe(TaskWhenKind.Cron);
        task.When.Value.ShouldBe("0 7 * * 1-5");
        task.When.TimeZone.ShouldBe("Europe/Berlin");
        task.RequireApproval.ShouldBeTrue();
        task.Acceptance.ShouldContain("nvda.json");
        task.Acceptance.ShouldContain("Aktuelle Zahlen");
        task.BlockedBy.ShouldBe(["t-4b1e", "t-9a2c"]);
        task.OnlyWhenMarketOpen.ShouldBeFalse();
        task.Body.ShouldBe("Recherchiere die neuesten Quartalszahlen.");
    }

    [Fact]
    public void Serialising_and_reading_back_gives_the_same_definition()
    {
        var original = new TaskItem
        {
            Id = "t-abc123",
            Title = "Titel mit: Doppelpunkt und # Raute",
            Status = TaskItemStatus.InReview,
            Type = TaskItemType.Approval,
            Priority = 5,
            Assignee = "@human",
            When = new TaskWhen { Kind = TaskWhenKind.Every, Value = "30m", TimeZone = "UTC" },
            RequireApproval = true,
            Acceptance = "Zeile eins\nZeile zwei",
            BlockedBy = ["t-1", "t-2"],
            OnlyWhenMarketOpen = true,
            Body = "Mehrzeiliger\nRumpf mit Umlauten äöü und 🦀."
        };

        var text = TaskFrontmatter.Serialize(original);
        TaskFrontmatter.TryParse(text, out var round, out var error).ShouldBeTrue(error);

        round.Id.ShouldBe(original.Id);
        round.Title.ShouldBe(original.Title);
        round.Status.ShouldBe(original.Status);
        round.Type.ShouldBe(original.Type);
        round.Priority.ShouldBe(original.Priority);
        round.Assignee.ShouldBe(original.Assignee);
        round.When!.Kind.ShouldBe(TaskWhenKind.Every);
        round.When.Value.ShouldBe("30m");
        round.When.TimeZone.ShouldBe("UTC");
        round.RequireApproval.ShouldBeTrue();
        round.Acceptance.ShouldBe(original.Acceptance);
        round.BlockedBy.ShouldBe(["t-1", "t-2"]);
        round.OnlyWhenMarketOpen.ShouldBeTrue();
        round.Body.ShouldBe(original.Body);
    }

    [Fact]
    public void An_assignee_with_at_survives_the_round_trip()
    {
        // In YAML a leading '@' is reserved — without quoting it would get lost.
        var task = new TaskItem { Id = "t-1", Title = "x", Assignee = "@new" };

        var text = TaskFrontmatter.Serialize(task);
        TaskFrontmatter.TryParse(text, out var round, out _).ShouldBeTrue();

        round.Assignee.ShouldBe("@new");
        TaskAssignee.KindOf(round.Assignee).ShouldBe(TaskAssigneeKind.New);
    }

    [Fact]
    public void Without_when_it_is_a_one_off_task()
    {
        var text = """
            ---
            id: t-1
            title: Einmalig
            assignee: "@new"
            ---
            Mach das einmal.
            """;

        TaskFrontmatter.TryParse(text, out var task, out _).ShouldBeTrue();
        task.When.ShouldBeNull();
    }

    [Fact]
    public void Missing_fields_fall_back_to_safe_defaults()
    {
        var text = """
            ---
            id: t-1
            title: Minimal
            ---
            """;

        TaskFrontmatter.TryParse(text, out var task, out _).ShouldBeTrue();

        task.Status.ShouldBe(TaskItemStatus.Todo);
        task.Type.ShouldBe(TaskItemType.Work);
        task.Priority.ShouldBe(3);
        task.Assignee.ShouldBe(TaskAssignee.Human, "ohne Zuordnung wartet die Aufgabe auf einen Menschen");
        task.RequireApproval.ShouldBeFalse();
        task.BlockedBy.ShouldBeEmpty();
    }

    [Fact]
    public void An_unknown_schedule_kind_is_discarded_instead_of_guessed()
    {
        var text = """
            ---
            id: t-1
            title: x
            when:
              kind: phantasie
              value: irgendwas
              tz: UTC
            ---
            """;

        TaskFrontmatter.TryParse(text, out var task, out _).ShouldBeTrue();
        task.When.ShouldBeNull();
    }

    [Fact]
    public void If_the_frontmatter_block_is_missing_the_parser_reports_it()
    {
        TaskFrontmatter.TryParse("Nur Text, kein Frontmatter.", out _, out var error).ShouldBeFalse();
        error.ShouldNotBeNull();
    }

    [Fact]
    public void An_unclosed_block_is_reported()
    {
        var text = "---\nid: t-1\ntitle: x\n";
        TaskFrontmatter.TryParse(text, out _, out var error).ShouldBeFalse();
        error.ShouldNotBeNull();
    }

    [Fact]
    public void Windows_line_endings_do_no_harm()
    {
        var text = "---\r\nid: t-1\r\ntitle: Mit CRLF\r\n---\r\nRumpf\r\n";
        TaskFrontmatter.TryParse(text, out var task, out var error).ShouldBeTrue(error);
        task.Title.ShouldBe("Mit CRLF");
        task.Body.ShouldBe("Rumpf");
    }
}