using System.Collections;
using System.IO;
using System;
using Cairo;
using Pango;

public struct HelpItem {
	public string Key;
	public string Text;

	public HelpItem(string key, string text) {
		Key = key;
		Text = text;
	}

	public override string ToString() {
		return "<b>" + Key + "</b>\t" + Text;
	}
}

public class HelpBox {
	private Pango.Context pc;
	private Pango.FontDescription titleFont;
	private Pango.FontDescription textFont;
	private string helpTitle;
	private HelpItem[] helpText;
	private int Width = 480;
	private int Height = 360;
	private int Columns = 3;

	public HelpBox(Pango.Context pc, string title, HelpItem[] items) {
		this.pc = pc;
		helpTitle = title;
		helpText = items;
		init();
	}

	public HelpBox(Pango.Context pc, string filename) {
		StreamReader file = new StreamReader(filename);
		string line;
		ArrayList items = new ArrayList();

		this.pc = pc;
		helpTitle = file.ReadLine();
		while ((line = file.ReadLine()) != null) {
			string[] i = line.Split(null);
			if (i.Length == 2) {
				items.Add(new HelpItem(i[0], i[1]));
			}
		}
		helpText = new HelpItem[items.Count];
		for (int i = 0; i < items.Count; i++) {
			helpText[i] = (HelpItem) items[i];
		}
		init();
	}

	private void init() {
		titleFont = Pango.FontDescription.FromString("Helvetica Bold 24");
		textFont = Pango.FontDescription.FromString("Helvetica 16");
		Pango.FontMetrics fmTitle = pc.GetMetrics(titleFont, null);
		Pango.FontMetrics fmText = pc.GetMetrics(textFont, null);
		int hTitle = Pango.Units.ToPixels(fmTitle.Ascent + fmTitle.Descent);
		int hText = Pango.Units.ToPixels(fmText.Ascent + fmText.Descent);

		Width = 480;
		for (int i = 0; i < helpText.Length; i++) {
			Pango.Layout layout = new Pango.Layout(pc);
			Pango.Rectangle r, r2;

			layout.FontDescription = textFont;
			layout.SetMarkup(helpText[i].ToString());
			layout.GetExtents(out r, out r2);
			int pw = Pango.Units.ToPixels(r2.Width);
			if ((pw + 8) * Columns > Width) {
				Width = (pw + 8) * Columns;
			}
		}
		Height = hTitle + (helpText.Length / 3 + 1) * hText + 12;
	}

        public void draw(Cairo.Context gr, int width, int height) {
		Pango.Layout layout;
		Cairo.Rectangle r = new Cairo.Rectangle(
			width / 2 - Width / 2,
			height / 2 - Height / 2,
			Width, Height);

		gr.SetSourceRGBA(1.0, 1.0, 1.0, 0.8);
		gr.NewPath();
		gr.Rectangle(r);
		gr.Fill();

		gr.SetSourceRGB(0.0, 0.0, 0.0);
		gr.NewPath();
		gr.Rectangle(r);
		gr.Stroke();

		gr.MoveTo(r.X + 4, r.Y + 4);
		layout = new Pango.Layout(pc);
		layout.SetText(helpTitle);
		layout.Width = Pango.Units.FromPixels((int)r.Width);
		layout.FontDescription = titleFont;
		Pango.CairoHelper.ShowLayout(gr, layout);

		int ii = 0;
		int ColumnWidth = Width / Columns;
		int ColumnLines = helpText.Length / Columns + 1;
		for (int i = 0; i < Columns; i++) {
			gr.MoveTo(r.X + 4 + (i * ColumnWidth), r.Y + 38);
			string column = "";
			for (int j = 0; j < ColumnLines && ii < helpText.Length; j++) {
				column += helpText[ii].ToString() + "\n";
				ii++;
			}
			layout = new Pango.Layout(pc);
			layout.SetMarkup(column);
			layout.Width = Pango.Units.FromPixels(ColumnWidth);
			layout.FontDescription = textFont;
			Pango.CairoHelper.ShowLayout(gr, layout);
		}
        }
}