// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
#nullable disable
 
using System.Globalization;
 
namespace Microsoft.DotNet.Cli;
 
// Represents a table (with rows of type T) that can be printed to a terminal.
internal class PrintableTable<T>
{
    public const string ColumnDelimiter = "      ";
    private readonly List<Column> _columns = [];
 
    private class Column
    {
        public string Header { get; set; }
        public Func<T, string> GetContent { get; set; }
        public int MaxWidth { get; set; }
        public override string ToString() { return Header; }
    }
 
    public void AddColumn(string header, Func<T, string> getContent, int maxWidth = int.MaxValue)
    {
        if (getContent == null)
        {
            throw new ArgumentNullException(nameof(getContent));
        }
 
        if (maxWidth <= 0)
        {
            throw new ArgumentException(
                CliStrings.ColumnMaxWidthMustBeGreaterThanZero,
                nameof(maxWidth));
        }
 
        _columns.Add(
            new Column()
            {
                Header = header,
                GetContent = getContent,
                MaxWidth = maxWidth
            });
    }
 
    public void PrintRows(IEnumerable<T> rows, Action<string> writeLine)
    {
        if (rows == null)
        {
            throw new ArgumentNullException(nameof(rows));
        }
 
        if (writeLine == null)
        {
            throw new ArgumentNullException(nameof(writeLine));
        }
 
        var widths = CalculateColumnWidths(rows);
        var totalWidth = CalculateTotalWidth(widths);
        if (totalWidth == 0)
        {
            return;
        }
 
        foreach (var line in EnumerateHeaderLines(widths))
        {
            writeLine(line);
        }
 
        writeLine(new string('-', totalWidth));
 
        foreach (var row in rows)
        {
            foreach (var line in EnumerateRowLines(row, widths))
            {
                writeLine(line);
            }
        }
    }
 
    public int CalculateWidth(IEnumerable<T> rows)
    {
        if (rows == null)
        {
            throw new ArgumentNullException(nameof(rows));
        }
 
        return CalculateTotalWidth(CalculateColumnWidths(rows));
    }
 
    private IEnumerable<string> EnumerateHeaderLines(int[] widths)
    {
        if (_columns.Count != widths.Length)
        {
            throw new InvalidOperationException();
        }
 
        return EnumerateLines(widths, [.. _columns.Select(c => new StringInfo(c.Header ?? ""))]);
    }
 
    private IEnumerable<string> EnumerateRowLines(T row, int[] widths)
    {
        if (_columns.Count != widths.Length)
        {
            throw new InvalidOperationException();
        }
 
        return EnumerateLines(widths, [.. _columns.Select(c => new StringInfo(c.GetContent(row) ?? ""))]);
    }
 
    private static IEnumerable<string> EnumerateLines(int[] widths, StringInfo[] contents)
    {
        if (widths.Length != contents.Length)
        {
            throw new InvalidOperationException();
        }
 
        if (contents.Length == 0)
        {
            yield break;
        }
 
        var builder = new StringBuilder();
        for (int line = 0; true; ++line)
        {
            builder.Clear();
 
            bool emptyLine = true;
            bool appendDelimiter = false;
            for (int i = 0; i < contents.Length; ++i)
            {
                // Skip zero-width columns entirely
                if (widths[i] == 0)
                {
                    continue;
                }
 
                if (appendDelimiter)
                {
                    builder.Append(ColumnDelimiter);
                }
 
                var startIndex = line * widths[i];
                var length = contents[i].LengthInTextElements;
                if (startIndex < length)
                {
                    var endIndex = (line + 1) * widths[i];
                    length = endIndex >= length ? length - startIndex : widths[i];
                    builder.Append(contents[i].SubstringByTextElements(startIndex, length));
                    builder.Append(' ', widths[i] - length);
                    emptyLine = false;
                }
                else
                {
                    // No more content for this column; append whitespace to fill remaining space
                    builder.Append(' ', widths[i]);
                }
 
                appendDelimiter = true;
            }
 
            if (emptyLine)
            {
                // Yield an "empty" line on the first line only
                if (line == 0)
                {
                    yield return builder.ToString();
                }
                yield break;
            }
 
            yield return builder.ToString();
        }
    }
 
    private int[] CalculateColumnWidths(IEnumerable<T> rows)
    {
        return [.. _columns.Select(c =>
        {
            var width = new StringInfo(c.Header ?? "").LengthInTextElements;
 
            foreach (var row in rows)
            {
                width = Math.Max(
                    width,
                    new StringInfo(c.GetContent(row) ?? "").LengthInTextElements);
            }
 
            return Math.Min(width, c.MaxWidth);
        })];
    }
 
    private static int CalculateTotalWidth(int[] widths)
    {
        int sum = 0;
        int count = 0;
 
        foreach (var width in widths)
        {
            if (width == 0)
            {
                // Skip zero-width columns
                continue;
            }
 
            sum += width;
            ++count;
        }
 
        if (count == 0)
        {
            return 0;
        }
 
        return sum + (ColumnDelimiter.Length * (count - 1));
    }
}