using System.Globalization;
using MeterVault.App.Analysis;

namespace MeterVault.Integration.Tests.Analysis;

/// <summary>The CSV of the analysis table (D-55): invariant numbers, local ISO bounds, empty unknowns, safe text. Pure.</summary>
public sealed class AnalysisCsvWriterTests
{
    private static readonly TimeSpan Cet = TimeSpan.FromHours(1);

    [Fact]
    public void Rows_are_written_with_invariant_numbers_whatever_the_culture()
    {
        var row = new AnalysisCsvRow(
            "m12", "Zähler Haus", "Consumption", "kWh",
            new DateTimeOffset(2024, 1, 1, 0, 0, 0, Cet), new DateTimeOffset(2024, 2, 1, 0, 0, 0, Cet), "Europe/Berlin",
            1234.5, "Available", "Measured|Estimated", 370.35, "Priced", "EUR", 0.1 + 0.2);

        var previous = CultureInfo.CurrentCulture;
        string csv;
        try
        {
            CultureInfo.CurrentCulture = CultureInfo.GetCultureInfo("de");
            csv = AnalysisCsvWriter.Write([row]);
        }
        finally
        {
            CultureInfo.CurrentCulture = previous;
        }

        var lines = csv.Split("\r\n", StringSplitOptions.RemoveEmptyEntries);
        Assert.Equal(
            "series_id,series_name,kind,unit,bucket_start,bucket_end,timezone,value,status,provenance,cost,cost_status,currency,comparison_value",
            lines[0]);
        Assert.Equal(
            "m12,Zähler Haus,Consumption,kWh,2024-01-01T00:00:00+01:00,2024-02-01T00:00:00+01:00,Europe/Berlin,1234.5,Available,Measured|Estimated,370.35,Priced,EUR,0.30000000000000004",
            lines[1]);
    }

    [Fact]
    public void Unknown_values_are_empty_cells_never_zero()
    {
        var row = new AnalysisCsvRow(
            "t3:use:kWh", "Strom · Total use", "Consumption", "kWh",
            new DateTimeOffset(2026, 9, 1, 0, 0, 0, TimeSpan.FromHours(2)), new DateTimeOffset(2026, 9, 19, 14, 37, 0, TimeSpan.FromHours(2)),
            "Europe/Berlin", null, "Missing", string.Empty, null, null, null, double.NaN);

        var line = AnalysisCsvWriter.Write([row]).Split("\r\n")[1];

        Assert.Equal(
            "t3:use:kWh,Strom · Total use,Consumption,kWh,2026-09-01T00:00:00+02:00,2026-09-19T14:37:00+02:00,Europe/Berlin,,Missing,,,,,",
            line);
    }

    [Theory]
    [InlineData("plain", "plain")]
    [InlineData("a,b", "\"a,b\"")]
    [InlineData("say \"hi\"", "\"say \"\"hi\"\"\"")]
    [InlineData("two\nlines", "\"two\nlines\"")]
    [InlineData("", "")]
    [InlineData(null, "")]
    public void Fields_are_quoted_as_rfc_4180_asks(string? field, string expected) =>
        Assert.Equal(expected, AnalysisCsvWriter.Escape(field));

    [Theory]
    [InlineData("=HYPERLINK(\"x\")", "'=HYPERLINK(\"x\")")]
    [InlineData("+1", "'+1")]
    [InlineData("-Solar", "'-Solar")]
    [InlineData("@home", "'@home")]
    [InlineData("Solar 1", "Solar 1")]
    public void User_text_cannot_become_a_spreadsheet_formula(string name, string expected) =>
        Assert.Equal(expected, AnalysisCsvWriter.Text(name));

    [Fact]
    public async Task The_async_writer_writes_the_same_text()
    {
        var row = new AnalysisCsvRow(
            "portfolio", "All energy types", "Cost", "EUR",
            new DateTimeOffset(2024, 1, 1, 0, 0, 0, Cet), new DateTimeOffset(2024, 2, 1, 0, 0, 0, Cet), "Europe/Berlin",
            -12.5, "Available", string.Empty, -12.5, "Priced", "EUR", null);
        await using var writer = new StringWriter(CultureInfo.InvariantCulture);

        await AnalysisCsvWriter.WriteAsync(writer, [row]);

        Assert.Equal(AnalysisCsvWriter.Write([row]), writer.ToString());
        Assert.Contains(",-12.5,Available,,-12.5,Priced,EUR,", writer.ToString(), StringComparison.Ordinal);
    }
}