using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Time.Testing;
using Volcanic.AgenticCore.Extensions.Scheduler;

namespace Volcanic.AgenticCore.Extensions.Tests.Scheduler;

public sealed class JobStoreTests : IDisposable
{
    private static readonly DateTimeOffset Now = new(2026, 9, 26, 14, 3, 0, TimeSpan.Zero);
    private readonly string _root = Directory.CreateTempSubdirectory("jobstore-").FullName;
    private readonly FakeTimeProvider _time = new(Now);

    private string StorePath => Path.Combine(_root, "scheduler", "jobs.json");
    private JobStore Store() => new(StorePath, _time, NullLogger.Instance);

    internal static ScheduledJob Prompt(string id, string target = "111") => new()
    {
        Id = id, Target = target, Name = "Call the dentist", Kind = JobKind.Prompt, Text = "Call the dentist",
        Schedule = new JobSchedule(Now.AddDays(1), null), CreatedAt = Now,
    };

    public void Dispose()
    {
        try { Directory.Delete(_root, recursive: true); } catch (IOException) { }
    }

    [Fact]
    public async Task Missing_file_loads_empty() => Assert.Empty(await Store().LoadAsync(CancellationToken.None));

    [Fact]
    public async Task Round_trip_keeps_jobs_and_leaves_no_temp_file()
    {
        var watcher = new ScheduledJob
        {
            Id = "w8r4t", Target = "111", Name = "Price check", Kind = JobKind.Watcher, Command = "scripts/price.sh",
            TimeoutSeconds = 60, Schedule = new JobSchedule(null, "*/10 * * * *"), CreatedAt = Now,
            LastRunAt = Now, LastResult = new JobResult(false, 1, false, "boom", Now),
        };
        await Store().SaveAsync([Prompt("k7m2q"), watcher], CancellationToken.None);

        Assert.Equal([Prompt("k7m2q"), watcher], await Store().LoadAsync(CancellationToken.None));
        Assert.Equal(["jobs.json"], Directory.GetFiles(Path.GetDirectoryName(StorePath)!).Select(Path.GetFileName));
    }

    [Fact]
    public async Task File_format_is_versioned_camel_case()
    {
        await Store().SaveAsync([Prompt("k7m2q")], CancellationToken.None);
        var json = await File.ReadAllTextAsync(StorePath);
        Assert.Contains("\"version\": 1", json);
        Assert.Contains("\"jobs\": [", json);
        Assert.Contains("\"kind\": \"prompt\"", json);
        Assert.NotEqual(0xEF, (await File.ReadAllBytesAsync(StorePath))[0]); // no BOM
    }

    [Fact]
    public async Task Corrupt_file_is_set_aside_and_loading_starts_empty()
    {
        Directory.CreateDirectory(Path.GetDirectoryName(StorePath)!);
        await File.WriteAllTextAsync(StorePath, "{ not json");

        Assert.Empty(await Store().LoadAsync(CancellationToken.None));
        Assert.False(File.Exists(StorePath));
        Assert.Equal("{ not json", await File.ReadAllTextAsync(StorePath + ".corrupt-20260926140300"));
    }

    [Fact]
    public async Task Invalid_entries_are_dropped()
    {
        Directory.CreateDirectory(Path.GetDirectoryName(StorePath)!);
        await File.WriteAllTextAsync(StorePath, """
            { "version": 1, "jobs": [
              { "id": "good1", "target": "111", "name": "ok", "kind": "prompt", "text": "hi", "schedule": { "cron": "0 9 * * *" }, "createdAt": "2026-09-26T14:03:00+00:00" },
              { "id": "both1", "target": "111", "name": "both", "kind": "prompt", "text": "hi", "schedule": { "at": "2026-09-27T09:00:00+00:00", "cron": "0 9 * * *" }, "createdAt": "2026-09-26T14:03:00+00:00" },
              { "id": "nocmd", "target": "111", "name": "watch", "kind": "watcher", "schedule": { "cron": "* * * * *" }, "createdAt": "2026-09-26T14:03:00+00:00" },
              { "id": "good1", "target": "111", "name": "duplicate id", "kind": "prompt", "text": "hi", "schedule": { "cron": "0 9 * * *" }, "createdAt": "2026-09-26T14:03:00+00:00" }
            ] }
            """);

        var jobs = await Store().LoadAsync(CancellationToken.None);

        Assert.Equal("ok", Assert.Single(jobs).Name);
    }

    [Fact]
    public async Task An_entry_that_does_not_deserialise_is_dropped_without_setting_the_file_aside()
    {
        Directory.CreateDirectory(Path.GetDirectoryName(StorePath)!);
        await File.WriteAllTextAsync(StorePath, """
            { "version": 1, "jobs": [
              { "id": "good1", "target": "111", "name": "ok", "kind": "prompt", "text": "hi", "schedule": { "cron": "0 9 * * *" }, "createdAt": "2026-09-26T14:03:00+00:00" },
              { "id": "kind1", "target": "111", "name": "bad kind", "kind": "alarm", "text": "hi", "schedule": { "cron": "0 9 * * *" }, "createdAt": "2026-09-26T14:03:00+00:00" },
              { "id": "noat1", "target": "111", "name": "no createdAt", "kind": "prompt", "text": "hi", "schedule": { "cron": "0 9 * * *" } },
              null,
              42
            ] }
            """);

        var jobs = await Store().LoadAsync(CancellationToken.None);

        Assert.Equal("good1", Assert.Single(jobs).Id);
        Assert.True(File.Exists(StorePath));
    }

    [Fact]
    public async Task A_stored_reminder_is_loaded_as_a_prompt()
    {
        Directory.CreateDirectory(Path.GetDirectoryName(StorePath)!);
        await File.WriteAllTextAsync(StorePath, """
            { "version": 1, "jobs": [
              { "id": "k7m2q", "target": "111", "name": "Dentist", "kind": "reminder", "text": "Call the dentist", "schedule": { "cron": "0 9 * * *" }, "createdAt": "2026-09-26T14:03:00+00:00" },
              { "id": "empty", "target": "111", "name": "No text", "kind": "reminder", "schedule": { "cron": "0 9 * * *" }, "createdAt": "2026-09-26T14:03:00+00:00" }
            ] }
            """);

        var job = Assert.Single(await Store().LoadAsync(CancellationToken.None));

        Assert.Equal(JobKind.Prompt, job.Kind);
        Assert.Equal("Remind me: Call the dentist", job.Text);
    }

    [Fact]
    public async Task Concurrent_saves_are_serialised()
    {
        var store = Store();
        await Task.WhenAll(Enumerable.Range(0, 20).Select(i => Task.Run(() => store.SaveAsync([Prompt($"id{i:000}")], CancellationToken.None))));

        Assert.Single(await Store().LoadAsync(CancellationToken.None));
        Assert.Empty(Directory.GetFiles(Path.GetDirectoryName(StorePath)!, "*.tmp"));
    }
}