using System.Collections.Generic;

namespace DownKyi.Core.Danmaku2Ass
{
    /// <summary>
    /// 创建器
    /// </summary>
    public class Creater
    {
        public Config Config;
        public List<Danmaku> Danmakus;
        public List<Subtitle> Subtitles;
        public string Text;

        public Creater(Config config, List<Danmaku> danmakus)
        {
            Config = config;
            Danmakus = danmakus;
            Subtitles = SetSubtitles();
            Text = SetText();
        }

        protected List<Subtitle> SetSubtitles()
        {
            var scroll = new Collision(Config.LineCount);
            var stayed = new Collision(Config.LineCount);
            Dictionary<string, Collision> collisions = new Dictionary<string, Collision>
            {
                { "scroll", scroll },
                { "top", stayed },
                { "bottom", stayed }
            };

            List<Subtitle> subtitles = new List<Subtitle>();
            foreach (var danmaku in Danmakus)
            {
                // 丢弃不支持的
                if (danmaku.Style == "none")
                {
                    continue;
                }

                // 创建显示方式对象
                var display = Display.Factory(Config, danmaku);
                var collision = collisions[danmaku.Style];
                var detect = collision.Detect(display);
                int lineIndex = detect.Item1;
                float waitingOffset = detect.Item2;

                // 超过容忍的偏移量，丢弃掉此条弹幕
                if (waitingOffset > Config.DropOffset)
                {
                    continue;
                }

                // 接受偏移，更新碰撞信息
                display.Relayout(lineIndex);
                collision.Update(display.Leave, lineIndex, waitingOffset);

                // 再加上自定义偏移
                float offset = waitingOffset + Config.CustomOffset;
                Subtitle subtitle = new Subtitle(danmaku, display, offset);

                subtitles.Add(subtitle);
            }
            return subtitles;
        }

        protected string SetText()
        {
            string header = Config.HeaderTemplate
                .Replace("{title}", Config.Title)
                .Replace("{width}", Config.ScreenWidth.ToString())
                .Replace("{height}", Config.ScreenHeight.ToString())
                .Replace("{fontname}", Config.FontName)
                .Replace("{fontsize}", Config.BaseFontSize.ToString());

            string events = string.Empty;
            foreach (var subtitle in Subtitles)
            {
                events += "\n" + subtitle.Text;
            }

            return header + events;
        }
    }
}