using System;
using System.Collections.Generic;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace FontPreview
{
	/// <summary>
	/// 缺字检测对话框：选一款已加载字体，输入测试文本，
	/// 用 cmap 表判断哪些字符该字体没有字形。
	/// </summary>
	public class GlyphCoverageDialog : Form
	{
		private List<FontItem> items;
		private ComboBox cboFont;
		private TextBox txtTest;
		private TextBox txtResult;
		private Label lblStat;

		public GlyphCoverageDialog(List<FontItem> items)
		{
			this.items = items;
			Text = "缺字检测";
			FormBorderStyle = FormBorderStyle.SizableToolWindow;
			StartPosition = FormStartPosition.CenterParent;
			ClientSize = new Size(560, 460);
			Font = new Font("Microsoft YaHei UI", 9f);
			MinimumSize = new Size(480, 400);

			Label l1 = new Label { Text = "字体：", Location = new Point(12, 15), Size = new Size(40, 20) };
			cboFont = new ComboBox { DropDownStyle = ComboBoxStyle.DropDownList, Location = new Point(56, 12), Size = new Size(480, 24) };
			foreach (FontItem it in items)
			{
				cboFont.Items.Add(it.DisplayName + "  ——  " + it.Name);
			}
			if (cboFont.Items.Count > 0) cboFont.SelectedIndex = 0;

			Label l2 = new Label { Text = "测试文字（逐字检查是否缺字）：", Location = new Point(12, 48), Size = new Size(300, 20) };
			txtTest = new TextBox
			{
				Multiline = true,
				ScrollBars = ScrollBars.Vertical,
				Location = new Point(12, 72),
				Size = new Size(524, 110),
				Text = SampleTexts.All[0].Text
			};

			Button btnGo = new Button { Text = "开始检测", Location = new Point(12, 190), Size = new Size(100, 28) };
			btnGo.Click += OnGo;

			lblStat = new Label { Text = "选择字体后点击“开始检测”", Location = new Point(122, 195), Size = new Size(414, 20) };

			txtResult = new TextBox
			{
				Multiline = true,
				ReadOnly = true,
				ScrollBars = ScrollBars.Vertical,
				Location = new Point(12, 226),
				Size = new Size(524, 222),
				BackColor = Color.White,
				Font = new Font("Microsoft YaHei UI", 10f)
			};

			Controls.Add(l1); Controls.Add(cboFont);
			Controls.Add(l2); Controls.Add(txtTest);
			Controls.Add(btnGo); Controls.Add(lblStat);
			Controls.Add(txtResult);
		}

		private void OnGo(object sender, EventArgs e)
		{
			if (cboFont.SelectedIndex < 0) { lblStat.Text = "请先选择字体"; return; }
			FontItem it = items[cboFont.SelectedIndex];
			FontCmap cmap = FontCmap.Load(it.Path);
			if (cmap == null)
			{
				lblStat.Text = "无法解析该字体（可能不是 TTF/OTF）";
				txtResult.Text = "";
				return;
			}

			string test = txtTest.Text ?? "";
			HashSet<int> seen = new HashSet<int>();
			List<string> missing = new List<string>();
			int total = 0;
			// 按 UTF-32 码点遍历，正确处理 emoji/代理对，避免孤立高代理项报错
			for (int i = 0; i < test.Length; i++)
			{
				char ch = test[i];
				if (char.IsWhiteSpace(ch) || char.IsPunctuation(ch)) continue;
				int cp;
				string chStr;
				if (char.IsHighSurrogate(ch) && i + 1 < test.Length && char.IsLowSurrogate(test[i + 1]))
				{
					cp = char.ConvertToUtf32(ch, test[i + 1]);
					chStr = new string(new char[] { ch, test[i + 1] });
					i++;
				}
				else if (char.IsSurrogate(ch))
				{
					continue; // 孤立代理项，跳过
				}
				else
				{
					cp = ch;
					chStr = ch.ToString();
				}
				if (!seen.Add(cp)) continue;
				total++;
				if (!cmap.HasGlyph(cp))
				{
					missing.Add(chStr);
				}
			}

			int cover = total - missing.Count;
			lblStat.Text = string.Format("共检查 {0} 个不同字符，覆盖 {1}，缺字 {2} 个", total, cover, missing.Count);
			if (missing.Count == 0)
			{
				txtResult.Text = "✓ 该字体覆盖测试文本中的全部字符，无缺字。";
			}
			else
			{
				StringBuilder sb = new StringBuilder();
				sb.AppendLine("以下字符该字体缺字（无字形）：");
				sb.AppendLine();
				sb.AppendLine(string.Join("  ", missing));
				sb.AppendLine();
				sb.AppendLine("建议：换字体或减少这些用字。");
				txtResult.Text = sb.ToString();
			}
		}
	}
}