using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using ChartForgeX.Core;
using ChartForgeX.Primitives;
using ChartForgeX.Rendering;
using ChartForgeX.Themes;
using ChartForgeX.Topology;
using ChartForgeX.Typography;
using ChartForgeX.VisualArtifacts;
using ChartForgeX.VisualBlocks;

// Optional exact gallery typography; copy the gallery's fonts directory beside this program.
FontRegistry.Register("CFX Proof Carlito", "fonts/Carlito-Regular.ttf", 400);
FontRegistry.Register("CFX Proof Carlito", "fonts/Carlito-Bold.ttf", 700);
var mode = VisualThemeMode.Light;
var theme = VisualTheme.Graphite();
var model = TrendLineRecipe.Create("compact-precision", mode);
var context = new VisualRenderContext(
    new VisualLayoutOptions(new VisualSize(360, 360)), theme, mode,
    new VisualFrame("Small signed drift", "Measured differences stay in their original units", showLegend: null, showSurface: false), FontSpec.FromFamily("CFX Proof Carlito"));
var prepared = model.Prepare(context);
File.WriteAllText("visual.svg", prepared.ToSvg());
File.WriteAllBytes("visual.png", prepared.ToPng());
File.WriteAllText("visual.html", prepared.ToArtifact("example", VisualArtifactKind.Chart).ToHtmlPage());

/// <summary>Builds a least-squares trend while retaining the observations used to fit it.</summary>
public static class TrendLineRecipe {
    /// <summary>Creates the selected trend example, including the small-drift precision case.</summary>
    public static Chart Create(string variant = "wide", VisualThemeMode mode = VisualThemeMode.Light) {
        if (variant is not ("wide" or "compact" or "sparse" or "options" or "compact-options" or "precision" or "compact-precision"))
            throw new ArgumentOutOfRangeException(nameof(variant));
        if (variant is "precision" or "compact-precision") {
            var drift = ChartSeries.CreateTrendLine(new ChartSeriesId("least-squares-drift"), "Least-squares drift",
                Enumerable.Range(0, 4096).Select(index => new ChartPoint(index % 10 + .5, index % 7 - 3)));
            return Chart.Create().WithXAxis("Measurement").WithYAxis("Fitted drift").AddSeries(drift);
        }
        var points = Enumerable.Range(1, 6).Where(index => variant != "sparse" || index is 1 or 3 or 6)
            .Select(index => new ChartPoint(index, 20 + index * 7 % 29, variant == "sparse" && index == 6)).ToArray();
        var observations = ChartSeries.CreateScatter(new ChartSeriesId("observations"), "Observations", points);
        var trend = ChartSeries.CreateTrendLine(new ChartSeriesId("least-squares-trend"), "Least-squares trend", points);
        return Chart.Create().WithXLabels("Mon", "Tue", "Wed", "Thu", "Fri", "Sat").AddSeries(observations).AddSeries(trend)
            .WithValueFormat(ChartValueFormat.Number("0.##", CultureInfo.InvariantCulture));
    }
}