using System.Text.Json;
using ClaudeDo.Worker.Config;
using ClaudeDo.Worker.Usage;

namespace ClaudeDo.Worker.Tests.Usage;

public class TranscriptUsageReaderTests : IDisposable
{
    private readonly string _root;
    private readonly WorkerConfig _cfg;

    public TranscriptUsageReaderTests()
    {
        _root = Path.Combine(Path.GetTempPath(), $"tur_{Guid.NewGuid():N}");
        Directory.CreateDirectory(_root);
        _cfg = new WorkerConfig
        {
            CentralWorktreeRoot = Path.Combine(_root, "central-worktrees"),
            SandboxRoot = Path.Combine(_root, "sandbox"),
        };
    }

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

    private string WriteSession(string projectDir, string file, params string[] lines)
    {
        var dir = Path.Combine(_root, "projects", projectDir);
        Directory.CreateDirectory(dir);
        var path = Path.Combine(dir, file);
        File.WriteAllLines(path, lines);
        return path;
    }

    private static string AssistantLine(
        string cwd, string ts, string model, long input, long output, long cacheRead, long cacheCreation,
        string? requestId = null, string? messageId = null) =>
        JsonSerializer.Serialize(new Dictionary<string, object?>
        {
            ["type"] = "assistant",
            ["cwd"] = cwd,
            ["timestamp"] = ts,
            ["requestId"] = requestId,
            ["message"] = new Dictionary<string, object?>
            {
                ["id"] = messageId,
                ["model"] = model,
                ["usage"] = new Dictionary<string, object?>
                {
                    ["input_tokens"] = input,
                    ["output_tokens"] = output,
                    ["cache_read_input_tokens"] = cacheRead,
                    ["cache_creation_input_tokens"] = cacheCreation,
                },
            },
        });

    private TranscriptUsageReader MakeReader() =>
        new(_cfg, Path.Combine(_root, "projects"));

    [Fact]
    public async Task Aggregates_By_Date_And_Model_Including_Cache_Tokens()
    {
        WriteSession("proj", "s.jsonl",
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 10, 20, 3, 1),
            AssistantLine(@"C:\Dev\App", "2026-06-01T09:00:00Z", "claude-sonnet-5", 5, 6, 1, 0),
            AssistantLine(@"C:\Dev\App", "2026-06-02T08:00:00Z", "claude-opus-5", 100, 200, 30, 10));

        var reader = MakeReader();
        var result = await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3));

        Assert.Equal(2, result.Count);
        var day1 = Assert.Single(result, r => r.Model == "claude-sonnet-5");
        Assert.Equal(new DateOnly(2026, 6, 1), day1.Date);
        Assert.Equal(15, day1.InputTokens);
        Assert.Equal(26, day1.OutputTokens);
        Assert.Equal(4, day1.CacheReadTokens);
        Assert.Equal(1, day1.CacheCreationTokens);
        Assert.Equal(2, day1.Messages);

        var day2 = Assert.Single(result, r => r.Model == "claude-opus-5");
        Assert.Equal(new DateOnly(2026, 6, 2), day2.Date);
        Assert.Equal(100, day2.InputTokens);
        Assert.Equal(1, day2.Messages);
    }

    [Fact]
    public async Task Same_RequestId_Across_Files_Counts_Once()
    {
        WriteSession("proj-a", "s1.jsonl",
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 10, 20, 0, 0, requestId: "req-1"));
        WriteSession("proj-b", "s2.jsonl",
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 10, 20, 0, 0, requestId: "req-1"));

        var reader = MakeReader();
        var result = await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3));

        var row = Assert.Single(result);
        Assert.Equal(1, row.Messages);
        Assert.Equal(10, row.InputTokens);
    }

    [Fact]
    public async Task Scope_Split_Covers_Sibling_Central_And_Sandbox_Roots()
    {
        var siblingCwd = Path.Combine(_root, "some-repo", ".claudedo-worktrees", "list-slug", "task-id");
        var centralCwd = Path.Combine(_cfg.CentralWorktreeRoot, "list-slug", "task-id");
        var sandboxCwd = Path.Combine(_cfg.SandboxRoot, "task-id");
        var otherCwd = Path.Combine(_root, "some-repo");

        WriteSession("proj", "s.jsonl",
            AssistantLine(siblingCwd, "2026-06-01T08:00:00Z", "claude-sonnet-5", 1, 1, 0, 0, requestId: "sibling"),
            AssistantLine(centralCwd, "2026-06-01T08:00:00Z", "claude-sonnet-5", 1, 1, 0, 0, requestId: "central"),
            AssistantLine(sandboxCwd, "2026-06-01T08:00:00Z", "claude-sonnet-5", 1, 1, 0, 0, requestId: "sandbox"),
            AssistantLine(otherCwd, "2026-06-01T08:00:00Z", "claude-sonnet-5", 1, 1, 0, 0, requestId: "other"));

        var reader = MakeReader();
        var result = await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3));

        Assert.Equal(2, result.Count);
        var claudeDo = Assert.Single(result, r => r.Scope == UsageScope.ClaudeDo);
        Assert.Equal(3, claudeDo.Messages);
        var other = Assert.Single(result, r => r.Scope == UsageScope.Other);
        Assert.Equal(1, other.Messages);
    }

    [Fact]
    public async Task Date_Filter_Excludes_Lines_Outside_Window()
    {
        WriteSession("proj", "s.jsonl",
            AssistantLine(@"C:\Dev\App", "2026-05-01T08:00:00Z", "claude-sonnet-5", 1, 1, 0, 0),
            AssistantLine(@"C:\Dev\App", "2026-06-02T08:00:00Z", "claude-sonnet-5", 5, 5, 0, 0),
            AssistantLine(@"C:\Dev\App", "2026-07-01T08:00:00Z", "claude-sonnet-5", 1, 1, 0, 0));

        var reader = MakeReader();
        var result = await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3));

        var row = Assert.Single(result);
        Assert.Equal(5, row.InputTokens);
        Assert.Equal(1, row.Messages);
    }

    [Fact]
    public async Task Malformed_Line_Does_Not_Abort_The_Run()
    {
        WriteSession("proj", "s.jsonl",
            "this is not json",
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 5, 5, 0, 0));

        var reader = MakeReader();
        var result = await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3));

        var row = Assert.Single(result);
        Assert.Equal(1, row.Messages);
    }

    [Fact]
    public async Task Cache_Skips_Unchanged_File_And_Picks_Up_Appended_Lines()
    {
        var path = WriteSession("proj", "s.jsonl",
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 5, 5, 0, 0, requestId: "req-a"));

        var reader = MakeReader();
        var first = Assert.Single(await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3)));
        Assert.Equal(1, first.Messages);

        // Overwrite with different content but the SAME length and mtime: if the reader honored
        // the cache it must still return the ORIGINAL aggregate, proving it did not re-read the file.
        var originalBytes = File.ReadAllBytes(path);
        var originalWriteUtc = File.GetLastWriteTimeUtc(path);
        var tamperedLine = AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 9, 9, 0, 0, requestId: "req-9");
        // Pad/truncate to the EXACT same byte length as the original file so the (length, mtime)
        // cache key still matches — the reader must then serve the cached (stale) aggregate.
        var tamperedPadded = tamperedLine.Length + 1 <= originalBytes.Length
            ? tamperedLine.PadRight(originalBytes.Length - 1) + "\n"
            : tamperedLine[..(originalBytes.Length - 1)] + "\n";
        var tamperedBytes = System.Text.Encoding.UTF8.GetBytes(tamperedPadded);
        Assert.Equal(originalBytes.Length, tamperedBytes.Length);
        File.WriteAllBytes(path, tamperedBytes);
        File.SetLastWriteTimeUtc(path, originalWriteUtc);

        var stale = Assert.Single(await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3)));
        Assert.Equal(5, stale.InputTokens);

        // Now really append a new line: length/mtime change, so the file must be re-read.
        File.AppendAllLines(path, new[]
        {
            AssistantLine(@"C:\Dev\App", "2026-06-01T09:00:00Z", "claude-sonnet-5", 3, 3, 0, 0, requestId: "req-b"),
        });

        var updated = Assert.Single(await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3)));
        Assert.Equal(2, updated.Messages);
    }

    [Fact]
    public async Task Missing_ProjectsRoot_Returns_Empty_Without_Throwing()
    {
        var reader = new TranscriptUsageReader(_cfg, Path.Combine(_root, "does-not-exist"));
        var result = await reader.ReadAsync(new DateOnly(2026, 6, 1), new DateOnly(2026, 6, 3));

        Assert.Empty(result);
    }

    [Fact]
    public async Task ReadSessionTotalsAsync_Sums_All_Assistant_Messages_In_The_Session_File()
    {
        WriteSession("proj", "sess-1.jsonl",
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 10, 20, 100, 5, requestId: "r1"),
            AssistantLine(@"C:\Dev\App", "2026-06-01T09:00:00Z", "claude-sonnet-5", 3, 7, 200, 0, requestId: "r2"));

        var reader = MakeReader();
        var totals = await reader.ReadSessionTotalsAsync("sess-1");

        Assert.NotNull(totals);
        Assert.Equal(13, totals!.InputTokens);
        Assert.Equal(27, totals.OutputTokens);
        Assert.Equal(300, totals.CacheReadTokens);
        Assert.Equal(5, totals.CacheCreationTokens);
    }

    [Fact]
    public async Task ReadSessionTotalsAsync_Skips_Synthetic_Model_Messages()
    {
        WriteSession("proj", "sess-2.jsonl",
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 10, 20, 0, 0, requestId: "r1"),
            AssistantLine(@"C:\Dev\App", "2026-06-01T09:00:00Z", "<synthetic>", 999, 999, 999, 999, requestId: "r2"));

        var reader = MakeReader();
        var totals = await reader.ReadSessionTotalsAsync("sess-2");

        Assert.NotNull(totals);
        Assert.Equal(10, totals!.InputTokens);
        Assert.Equal(20, totals.OutputTokens);
    }

    [Fact]
    public async Task ReadSessionTotalsAsync_Dedupes_By_RequestId_Within_The_Session()
    {
        WriteSession("proj", "sess-3.jsonl",
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:00Z", "claude-sonnet-5", 10, 20, 0, 0, requestId: "dup"),
            AssistantLine(@"C:\Dev\App", "2026-06-01T08:00:01Z", "claude-sonnet-5", 10, 20, 0, 0, requestId: "dup"));

        var reader = MakeReader();
        var totals = await reader.ReadSessionTotalsAsync("sess-3");

        Assert.NotNull(totals);
        Assert.Equal(10, totals!.InputTokens);
        Assert.Equal(20, totals.OutputTokens);
    }

    [Fact]
    public async Task ReadSessionTotalsAsync_Returns_Null_When_No_Matching_Transcript_File()
    {
        var reader = MakeReader();
        var totals = await reader.ReadSessionTotalsAsync("does-not-exist");

        Assert.Null(totals);
    }

    [Fact]
    public async Task ReadSessionTotalsAsync_Returns_Null_When_ProjectsRoot_Missing()
    {
        var reader = new TranscriptUsageReader(_cfg, Path.Combine(_root, "does-not-exist"));
        var totals = await reader.ReadSessionTotalsAsync("sess-1");

        Assert.Null(totals);
    }
}