using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;
using System.IO;
using static System.Linq.Enumerable;

namespace MusicGameMovieMaker
{
    class Note : IComparable<Note>
    {
        public int Time { get; }
        public int Line { get; }

        public Note(int time, int line)
        {
            this.Time = time;
            this.Line = line;
        }

        public int CompareTo(Note other)
        {
            var p = this.Time.CompareTo(other.Time);
            if (p != 0)
            {
                return p;
            }
            return this.Line.CompareTo(other.Line);
        }
    }

    static class Program
    {
        const int height = 480;//画面の高さ
        const int width = 640;//画面の幅
        const int noteSize = 20;//各ノーツのサイズ
        const double distanceBase = 7.5;//HiSpeed x1.0での表示距離
        const int border = 20;//判定の位置
        const int maxDisplay = height - border;//表示される限界の位置
        const int horizonDistance = 75;//各列の幅
        const double left = width / 2 - horizonDistance * 1.5;//左端の列

        //C++のstd::partition_pointに似た挙動をする関数(詳しくはcpprefjpを見よ)
        static int PartitionPoint<T>(List<T> list, Func<T, bool> pred)
        {
            var min = 0;
            var max = list.Count;
            while (max - min > 1)
            {
                var mid = (min + max) / 2;
                if (pred(list[mid]))
                {
                    min = mid;
                }
                else
                {
                    max = mid;
                }
            }
            return max;
        }

        static (int, int) ReadTuple2(TextReader reader)
        {
            var ar = reader.ReadLine().Split(' ').Select(int.Parse).ToArray();
            return (ar[0], ar[1]);
        }
        //BPMのデータを読み込む
        static List<int> ReadBPMList(string path)
        {
            using (var stream = new StreamReader(path))
            {
                var (N, maxTime) = ReadTuple2(stream);
                var ret = new List<int>();
                var impl = new List<(int Time, int BPM)>();
                foreach(var i in Range(0, N))
                {
                    impl.Add(ReadTuple2(stream));
                }
                impl.Add((maxTime, int.MaxValue));
                for (var (index, time) = (0, 0); time < maxTime; ++time)
                {
                    if (time == impl[index + 1].Time)
                    {
                        ++index;
                    }
                    ret.Add(impl[index].BPM);
                }
                return ret;
            }
        }
        //32分刻みでのノーツのデータを読み込む
        static List<Note> ReadNoteList(string path)
        {
            using(var stream = new StreamReader(path))
            {
                var ret = new List<Note>();
                var N = int.Parse(stream.ReadLine());
                foreach(var i in Range(0, N))
                {
                    var (time, line) = ReadTuple2(stream);
                    ret.Add(new Note(time, line));
                }
                ret.Sort();
                return ret;
            }
        }
        static void Main(string[] args)
        {
            var BPMList = ReadBPMList("bpmdata.txt");
            var noteData = ReadNoteList("notedata.txt");
            var minIndex = 0;
            var bpmIndex = 0;
            var hispeed = 1.5;
            var line = 0.0;
            var (changeTime, realBPMList) = BPMCheck(BPMList);
            minIndex = SaveImage(noteData, minIndex, hispeed, line, 0);
            // 1.0/60秒ずつ進むことを仮定する(ほぼ誤差の範囲だが厳密には60FPSにはならないことに注意せよ)
            const double minTime = 1.0 / 60;
            var realTime = 0.0;
            for (var frame = 1; minIndex < noteData.Count; ++frame)
            {
                var time = minTime;
                while (time != default)
                {
                    // BPMがxのときy秒で8*x*y/60回だけ32分を刻むことができる
                    line += Math.Min(changeTime[bpmIndex] - realTime, time) * realBPMList[bpmIndex] * 8 / 60;
                    time -= Math.Min(changeTime[bpmIndex] - realTime, time);
                    if (time != default)
                    {
                        ++bpmIndex;
                    }
                }
                realTime += minTime;
                minIndex = SaveImage(noteData, minIndex, hispeed, line, frame);
            }
        }

        static Pen Pen = new Pen(Color.Red, noteSize / 4);
        private static int SaveImage(List<Note> noteData, int minIndex, double hispeed, double line, int index)
        {
            // ノーツの中心と判定ラインの距離を返す
            double GetPosition(Note note)
            {
                return (note.Time - line) * hispeed * distanceBase;
            }
            var pIndex = PartitionPoint(noteData, n => GetPosition(n) < maxDisplay + noteSize);
            using (var bitmap = new Bitmap(width, height))
            {
                using (var g = Graphics.FromImage(bitmap))
                {
                    foreach (var i in Range(0, 4))
                    {
                        g.DrawRectangle(Pens.Red, (int)(left + (horizonDistance * i) - noteSize), border - noteSize, 2 * noteSize, 2 * noteSize);
                    }
                    for (var i = minIndex; i < pIndex; ++i)
                    {
                        var pos = GetPosition(noteData[i]);
                        if (pos < -noteSize - border)
                        {
                            minIndex = i + 1;
                        }
                        else
                        {
                            var noteLine = noteData[i].Line;
                            g.FillRectangle(Brushes.Blue, (int)(left + (horizonDistance * noteLine) - noteSize), (int)(pos + border - noteSize), 2 * noteSize, 2 * noteSize);
                            g.DrawRectangle(Pen, (int)(left + (horizonDistance * noteLine) - noteSize), (int)(pos + border - noteSize), 2 * noteSize, 2 * noteSize);
                        }
                    }
                }
                bitmap.Save($"image/{index + 1}.png", System.Drawing.Imaging.ImageFormat.Png);
                return minIndex;
            }
        }

        // BPMが変わる時間とそれに対応するBPMのリストをセットを返す
        private static (List<double> Change, List<int> RealBPMList) BPMCheck(List<int> BPMList)
        {
            var bpmChange = new List<double>();
            var realBpmList = new List<int>
            {
                BPMList[0]
            };
            var prev = BPMList[0];
            var time = 60.0 / (8.0 * prev);
            foreach (var bpm in BPMList.Skip(1))
            {
                if (bpm != prev)
                {
                    bpmChange.Add(time);
                    realBpmList.Add(bpm);
                }
                prev = bpm;
                time += 60.0 / (8.0 * bpm);
            }
            bpmChange.Add(double.MaxValue);
            return (bpmChange, realBpmList);
        }
    }
}