using System.Text.Json;
using ClawdDotNet.Core.Memory;
using ClawdDotNet.Core.Storage;
using ClawdDotNet.Core.Tools;
using ClawdDotNet.Tools.Memory;
using ClawdDotNet.Tools.Tests.FileRW;
using Microsoft.Extensions.Logging.Abstractions;
using Shouldly;

namespace ClawdDotNet.Tools.Tests.Memory;

/// <summary>
/// #607: The news agent remembered the whole, growing link list without a key at every run.
/// As soon as the newest entry alone was above 8,000 characters, recall delivered not a
/// single content any more - the agent would have considered every news item new again.
/// </summary>
public sealed class MemoryToolTests : IDisposable
{
    private readonly string _dir = Path.Combine(Path.GetTempPath(), "clawd-tests", Guid.NewGuid().ToString("N"));
    private readonly SqliteMemoryRepository _repository;
    private readonly MemoryTool _tool = new();

    public MemoryToolTests()
    {
        Directory.CreateDirectory(_dir);
        _repository = new SqliteMemoryRepository(new SqliteStorage(Path.Combine(_dir, "state.db")));
    }

    public void Dispose()
    {
        ClawdDotNet.Core.Storage.SqliteStorage.ReleasePooledConnections(_dir);
        try { Directory.Delete(_dir, recursive: true); }
        catch { /* Cleaning up is secondary */ }
    }

    private Task<ToolResult> Call(object input) => _tool.ExecuteAsync(
        JsonSerializer.SerializeToElement(input),
        new AgentToolContext("nachrichten", "inst", new Dictionary<string, object?>(), new NullStateStore(),
            NullLogger.Instance, CancellationToken.None, Memory: _repository),
        CancellationToken.None);

    private static string LinkList(int count)
        => string.Join("\n", Enumerable.Range(1, count).Select(i => $"https://www.tagesschau.de/inland/meldung-{i:D4}.html"));

    [Fact]
    public async Task A_single_oversized_entry_is_shortened_instead_of_dropped()
    {
        var list = LinkList(250);   // ~11,500 characters
        (await Call(new { action = "remember", subject = "gemeldet", content = list })).Success.ShouldBeTrue();

        var fetch = await Call(new { action = "recall", query = "gemeldet" });

        fetch.Success.ShouldBeTrue();
        fetch.Content.ShouldContain("meldung-0001.html", customMessage: "der Anfang bleibt sichtbar");
        fetch.Content.ShouldContain("meldung-0250.html", customMessage: "das Ende - die neuesten Links - bleibt sichtbar");
        fetch.Content.ShouldContain("truncated");
        fetch.Content.ShouldNotContain("more results omitted");
        fetch.Content.Length.ShouldBeLessThanOrEqualTo(8_000);
    }

    [Fact]
    public async Task If_the_newest_of_several_entries_is_too_large_it_stays_partly_visible()
    {
        await Call(new { action = "remember", subject = "gemeldet", content = LinkList(100) });
        await Task.Delay(20);
        await Call(new { action = "remember", subject = "gemeldet", content = LinkList(220) });

        var fetch = await Call(new { action = "recall", query = "gemeldet" });

        fetch.Content.ShouldContain("meldung-0220.html");
        fetch.Content.ShouldContain("1 more results omitted");
        fetch.Content.Length.ShouldBeLessThanOrEqualTo(8_000);
    }

    [Fact]
    public async Task What_fits_stays_unshortened()
    {
        await Call(new { action = "remember", subject = "gemeldet", content = LinkList(20) });

        var fetch = await Call(new { action = "recall", query = "gemeldet" });

        fetch.Content.ShouldNotContain("truncated");
        fetch.Content.ShouldContain("meldung-0010.html");
    }

    [Fact]
    public async Task Remembering_again_without_key_under_the_same_subject_points_to_key()
    {
        var firstOne = await Call(new { action = "remember", subject = "gemeldet", content = LinkList(3) });
        var secondOne = await Call(new { action = "remember", subject = "gemeldet", content = LinkList(5) });

        firstOne.Content.ShouldNotContain("Note:");
        secondOne.Content.ShouldContain("2 entries without a key");
        secondOne.Content.ShouldContain("key");
    }

    [Fact]
    public async Task With_key_it_is_updated_and_not_warned()
    {
        await Call(new { action = "remember", subject = "gemeldet", key = "gemeldete-links", content = LinkList(3) });
        var secondOne = await Call(new { action = "remember", subject = "gemeldet", key = "gemeldete-links", content = LinkList(5) });

        secondOne.Content.ShouldNotContain("Note:");
        (await _repository.CountAsync(MemoryScope.Agent, "nachrichten", CancellationToken.None)).ShouldBe(1);
    }

    [Fact]
    public async Task An_entry_near_the_recall_limit_is_flagged_when_remembering()
    {
        var result = await Call(new { action = "remember", subject = "gemeldet", key = "links", content = LinkList(120) });

        result.Content.ShouldContain("characters long");
    }
}