using System;
using System.Numerics;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using MLEM.Cameras;
using MLEM.Extensions;
using MLEM.Font;
using MLEM.Startup;
using ThemeParkClicker.Attractions;

namespace ThemeParkClicker {
    public class GameImpl : MlemGame {

        public static GameImpl Instance { get; private set; }
        private BigInteger tickets;
        public BigInteger Tickets {
            get => this.tickets;
            set {
                var diff = value - this.tickets;
                if (diff > 0)
                    this.ticketsPerSecondCounter += (long) diff;
                this.tickets = value;
            }
        }
        public ParkMap Map;
        public Camera Camera { get; private set; }
        public Ui Ui { get; private set; }
        public bool DrawMap;
        public DateTime LastUpdate;
        public float TicketsPerSecond { get; private set; }
        private long ticketsPerSecondCounter;
        private double secondCounter;
        private double saveCounter;

        public GameImpl() {
            Instance = this;
        }

        protected override void LoadContent() {
            base.LoadContent();
            this.Ui = new Ui(this.UiSystem);
            this.Camera = new Camera(this.GraphicsDevice) {
                Scale = 5,
                AutoScaleWithScreen = true,
                AutoScaleReferenceSize = new Point(720, 1280),
                MaxScale = 24,
                MinScale = 3
            };

            if (!SaveHandler.Load(this))
                this.Map = new ParkMap(10, 10);
        }

        protected override void DoUpdate(GameTime gameTime) {
            base.DoUpdate(gameTime);

            var now = DateTime.Now;
            if (this.LastUpdate != default) {
                var passed = now - this.LastUpdate;
                // if more than 1 second passed, the app is minimized or a save was loaded, so we penalize
                if (passed.TotalSeconds >= 1)
                    passed = new TimeSpan(passed.Ticks / 2);
                this.Map.Update(gameTime, passed);
            }
            this.LastUpdate = now;

            this.Ui.Update(gameTime);

            // we average tickets per second over 4 seconds
            const float avgTime = 4;
            this.secondCounter += gameTime.ElapsedGameTime.TotalSeconds;
            if (this.secondCounter >= avgTime) {
                this.secondCounter -= avgTime;
                this.TicketsPerSecond = this.ticketsPerSecondCounter / avgTime;
                this.ticketsPerSecondCounter = 0;
            }

            // save every 3 seconds
            this.saveCounter += gameTime.ElapsedGameTime.TotalSeconds;
            if (this.saveCounter >= 3) {
                this.saveCounter = 0;
                SaveHandler.Save(this);
            }
        }

        protected override void DoDraw(GameTime gameTime) {
            this.GraphicsDevice.Clear(Color.Black);
            if (this.DrawMap) {
                this.SpriteBatch.Begin(SpriteSortMode.Deferred, null, SamplerState.PointClamp, transformMatrix: this.Camera.ViewMatrix);
                this.Map.Draw(gameTime, this.SpriteBatch, Vector2.Zero, 1, 1);
                this.SpriteBatch.End();
            }
            base.DoDraw(gameTime);
        }

        public string DisplayTicketCount() {
            if (this.Tickets < 1000)
                return this.Tickets.ToString();
            // thousands
            if (this.Tickets < 1000000)
                return this.Tickets.ToString("0,.##K");
            // millions
            if (this.Tickets < 1000000000)
                return this.Tickets.ToString("0,,.##M");
            // billions
            if (this.Tickets < 1000000000000)
                return this.Tickets.ToString("0,,,.##B");
            // trillions
            if (this.Tickets < 1000000000000000)
                return this.Tickets.ToString("0,,,,.##T");
            return this.Tickets.ToString("0,,,,,.##Q");
        }

    }
}