// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using System;
using System.Collections;
using System.Collections.Generic;

using NStack;

using Terminal.Gui;

namespace OutGridView.Cmdlet
{
    internal sealed class GridViewDataSource : IListDataSource
    {
        public List<GridViewRow> GridViewRowList { get; set; }

        public int Count => GridViewRowList.Count;

        public GridViewDataSource(List<GridViewRow> itemList)
        {
            GridViewRowList = itemList;
        }

        public int Length { get; }

        public void Render(ListView container, ConsoleDriver driver, bool selected, int item, int col, int line, int width, int start)
        {
            container.Move(col, line);
            RenderUstr(driver, GridViewRowList[item].DisplayString, col, line, width);
        }

        public bool IsMarked(int item) => GridViewRowList[item].IsMarked;

        public void SetMark(int item, bool value)
        {
            var oldValue = GridViewRowList[item].IsMarked;
            GridViewRowList[item].IsMarked = value;
            var args = new RowMarkedEventArgs()
            {
                Row = GridViewRowList[item],
                OldValue = oldValue
            };
            MarkChanged?.Invoke(this, args);
        }

        public sealed class RowMarkedEventArgs : EventArgs
        {
            public GridViewRow Row { get; set; }
            public bool OldValue { get; set; }

        }

        public event EventHandler<RowMarkedEventArgs> MarkChanged;

        public IList ToList()
        {
            return GridViewRowList;
        }

        // A slightly adapted method from gui.cs: https://github.com/migueldeicaza/gui.cs/blob/fc1faba7452ccbdf49028ac49f0c9f0f42bbae91/Terminal.Gui/Views/ListView.cs#L433-L461
        private static void RenderUstr(ConsoleDriver driver, ustring ustr, int col, int line, int width)
        {
            int used = 0;
            int index = 0;
            while (index < ustr.Length)
            {
                (var rune, var size) = Utf8.DecodeRune(ustr, index, index - ustr.Length);
                var count = Rune.ColumnWidth(rune);
                if (used + count > width) break;
                driver.AddRune(rune);
                used += count;
                index += size;
            }

            while (used < width)
            {
                driver.AddRune(' ');
                used++;
            }
        }
    }
}