Price Tag

using System;
using cAlgo.API;
using cAlgo.API.Internals;
using System.Linq;

namespace cAlgo
{
    [Indicator(IsOverlay = true, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
    public class PriceTag : Indicator
    {
        private Color _color;
        private const string OBJECTS_NAME_PREFIX = "PriceTag";

        [Parameter("Modifier", DefaultValue = ModifierKeys.Shift, Group = "Hotkey")]
        public ModifierKeys HotkeyModifier { get; set; }

        [Parameter("Name/Code", DefaultValue = "Red", Group = "Color")]
        public string ColorName { get; set; }

        [Parameter("Alpha", DefaultValue = 255, MinValue = 0, MaxValue = 255, Group = "Color")]
        public int ColorAlpha { get; set; }

        [Parameter("Font Size", DefaultValue = 10, MinValue = 0, Step = 1, Group = "Text")]
        public double FontSize { get; set; }

        protected override void Initialize()
        {
            _color = GetColor(ColorName, ColorAlpha);

            var priceTags = from chartObject in Chart.Objects
                            where chartObject.Name.StartsWith(OBJECTS_NAME_PREFIX, StringComparison.Ordinal)
                            where string.IsNullOrWhiteSpace(chartObject.Comment)
                            select chartObject as ChartText;

            foreach (var priceTag in priceTags)
            {
                priceTag.Color = _color;
                priceTag.FontSize = FontSize;
            }

            Chart.ObjectsUpdated += Chart_ObjectsUpdated;
            Chart.MouseDown += Chart_MouseDown;
        }

        private void Chart_ObjectsUpdated(ChartObjectsUpdatedEventArgs obj)
        {
            foreach (var updatedObject in obj.ChartObjects)
            {
                if ((updatedObject is ChartText) == false
                    || !updatedObject.Name.StartsWith(OBJECTS_NAME_PREFIX, StringComparison.Ordinal))
                {
                    continue;
                }

                var chartText = updatedObject as ChartText;

                SetPrice(chartText);
            }
        }

        private void Chart_MouseDown(ChartMouseEventArgs obj)
        {
            if ((HotkeyModifier == ModifierKeys.Alt && !obj.AltKey)
                || (HotkeyModifier == ModifierKeys.Control && !obj.CtrlKey)
                || (HotkeyModifier == ModifierKeys.Shift && !obj.ShiftKey))
            {
                return;
            }

            AddPriceTag(obj.TimeValue, obj.YValue, _color);
        }

        public override void Calculate(int index)
        {
        }

        private Color GetColor(string colorString, int alpha = 255)
        {
            var color = colorString[0] == '#' ? Color.FromHex(colorString) : Color.FromName(colorString);

            return Color.FromArgb(alpha, color);
        }

        private void AddPriceTag(DateTime time, double yValue, Color color)
        {
            var name = string.Format("PriceTag_{0}", DateTime.UtcNow.Ticks);

            var text = Chart.DrawText(name, string.Empty, time, yValue, color);
            text.IsInteractive = true;
            text.IsLocked = true;
            text.FontSize = FontSize;

            SetPrice(text);
        }

        private void SetPrice(ChartText chartText)
        {
            var barIndex = Bars.OpenTimes.GetIndexByTime(chartText.Time);

            var arrowType = string.Empty;

            if (chartText.Y < Bars.LowPrices[barIndex])
            {
                arrowType = "↑ ";
            }
            else if (chartText.Y > Bars.LowPrices[barIndex])
            {
                arrowType = "↓ ";
            }

            chartText.Text = string.Format("{0}{1}", arrowType, Math.Round(chartText.Y, Symbol.Digits));
        }
    }
}