using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using MLEM.Cameras;
using MLEM.Extended.Extensions;
using MLEM.Extended.Tiled;
using MLEM.Extensions;
using MLEM.Misc;
using MLEM.Startup;
using MLEM.Textures;
using MonoGame.Extended;
using MonoGame.Extended.Tiled;

namespace GreatSpringGameJam {
    public class Map {

        private static readonly UniformTextureAtlas BackgroundTexture = new(MlemGame.LoadContent<Texture2D>("Textures/Backgrounds"), 8, 8);
        public Point SizeInPixels => new(this.map.WidthInPixels, this.map.HeightInPixels);
        public Point SpawnPoint => new(this.map.Properties.GetInt("StartX"), this.map.Properties.GetInt("StartY"));
        public Point Size => new(this.map.Width, this.map.Height);
        public Vector2 TileSize => this.map.GetTileSize();
        public readonly TiledMapCollisions Collisions;
        public readonly int TotalSnow;
        public readonly int TotalSeeds;
        public readonly int TotalGnomes;

        private readonly TiledMap map;
        private readonly IndividualTiledMapRenderer renderer;
        private readonly List<Entity> entities = new();

        public Map(TiledMap map) {
            this.map = map;
            this.renderer = new IndividualTiledMapRenderer(this.map);
            this.Collisions = new TiledMapCollisions(this.map);
            this.TotalSnow = this.GetTotalTiles("Snow");
            this.TotalSeeds = this.GetTotalTiles("Seed");

            foreach (var (pos, _) in this.EnumerateTiles("Gnome")) {
                this.entities.Add(new Gnome(this, new Vector2(pos.X, pos.Y)));
                this.SetTile(pos.Layer, pos.X, pos.Y, 0);
            }
            this.TotalGnomes = this.entities.OfType<Gnome>().Count();
        }

        public void AddEntity(Entity entity) {
            this.entities.Add(entity);
        }

        public void RemoveEntity(Entity entity) {
            this.entities.Remove(entity);
        }

        public IEnumerable<T> GetEntities<T>() where T : Entity {
            return this.entities.OfType<T>();
        }

        public void Update(GameTime time) {
            this.renderer.UpdateAnimations(time);
            for (var i = this.entities.Count - 1; i >= 0; i--)
                this.entities[i].Update(time);
        }

        public TiledMapTile GetTile(string layer, int x, int y) {
            return this.map.GetTile(layer, x, y);
        }

        public void SetTile(string layer, int x, int y, int globalId) {
            var index = this.map.GetTileLayerIndex(layer);
            this.map.SetTile(layer, x, y, globalId);
            this.renderer.UpdateDrawInfo(index, x, y);
            this.Collisions.UpdateCollisionInfo(index, x, y);
        }

        public void SetTile(string layer, int x, int y, TiledMapTileset tileset, TiledMapTilesetTile tile) {
            this.SetTile(layer, x, y, tile.GetGlobalIdentifier(tileset, this.map));
        }

        public TiledMapTilesetTile GetTilesetTile(TiledMapTile tile, TiledMapTileset tileset) {
            return tileset.GetTilesetTile(tile, this.map);
        }

        public TiledMapTileset GetTileset(TiledMapTile tile) {
            return tile.GetTileset(this.map);
        }

        public void Draw(GameTime time, SpriteBatch batch, Camera camera) {
            batch.Begin(SpriteSortMode.Deferred, null, SamplerState.PointClamp, transformMatrix: camera.ViewMatrix);
            // render background
            const float parallaxFactor = 0.5F;
            var parallax = camera.Position * parallaxFactor;
            var (parW, parH) = this.SizeInPixels.ToVector2() * (1 - parallaxFactor) + camera.ScaledViewport * parallaxFactor;
            var mountains = BackgroundTexture[0, 0, 8, 4];
            for (var x = 0; x < parW; x += mountains.Width * 2) {
                batch.Draw(mountains, parallax + new Vector2(x, parH - mountains.Height * 2), Color.White * 0.5F, 0, Vector2.Zero, 2, SpriteEffects.None, 0);
            }

            // render map etc.
            this.DrawLayer(batch, "Background", camera);
            this.DrawLayer(batch, "Ground", camera);
            foreach (var entity in this.entities)
                entity.Draw(time, batch);
            this.DrawLayer(batch, "Foreground", camera);
            this.DrawLayer(batch, "Snow", camera);
            batch.End();
        }

        public int GetTotalTiles(string type) {
            return this.EnumerateTiles(type).Count();
        }

        public IEnumerable<(LayerPosition, TiledMapTilesetTile)> EnumerateTiles(string type) {
            for (var x = 0; x < this.map.Width; x++) {
                for (var y = 0; y < this.map.Height; y++) {
                    foreach (var layer in this.map.TileLayers) {
                        var tile = layer.GetTile(x, y);
                        if (tile.IsBlank)
                            continue;
                        var tilesetTile = this.GetTilesetTile(tile, this.GetTileset(tile));
                        if (tilesetTile.Properties.GetBool(type))
                            yield return (new LayerPosition(layer.Name, x, y), tilesetTile);
                    }
                }
            }
        }

        private void DrawLayer(SpriteBatch batch, string layer, Camera camera) {
            var id = this.map.GetTileLayerIndex(layer);
            if (id >= 0)
                this.renderer.DrawLayer(batch, id, camera.GetVisibleRectangle().ToExtended());
        }

    }
}