using System;
using FOU.Scripts.Elements;
using Godot;

namespace FOU.Scripts;

public class Level {

    public Vector2I Resolution;

    private Chunk[,] chunks;
    private Image image;

    private int chunksPerX;
    private int chunksPerY;

    // per chunk:
    private int chunkResX;
    private int chunkResY;

    private float rainAmount = 0;

    public Level(Main main, int sizeX, int sizeY) {
        Resolution = new Vector2I(sizeX, sizeY);
        chunksPerX = main.ChunksPerAxis;
        chunksPerY = main.ChunksPerAxis;

        chunkResX = sizeX / chunksPerX;
        chunkResY = sizeY / chunksPerY;

        GD.Print($"Generating level ({sizeX}:{sizeY}) with {chunksPerX*chunksPerY} chunks ({chunkResX} * {chunkResY})");

        image = Image.Create(sizeX, sizeY, false, Image.Format.Rgb8);

        chunks = new Chunk[chunksPerX, chunksPerY];
        int index = 0;
        // create all chunks
        for (int x = 0; x < chunksPerX; x++) {
            for (int y = 0; y < chunksPerY; y++) {
                chunks[x, y] = new Chunk(chunkResX, chunkResY, index++);
            }
        }

        // assign neighbors
        for (int x = 0; x < chunksPerX; x++) {
            for (int y = 0; y < chunksPerY; y++) {

                if (y > 0) chunks[x, y].NeighborN = chunks[x, y-1];
                if (y < chunksPerY-1) chunks[x, y].NeighborS = chunks[x, y+1];

                if (x > 0) chunks[x, y].NeighborE = chunks[x-1, y];
                if (x < chunksPerX-1) chunks[x, y].NeighborW = chunks[x+1, y];
            }
        }
    }

    public void Update() {
        MakeItRain();

        foreach (Chunk c in chunks)
            c.Update();
    }

    public void SetRainAmount(float amount) {
        rainAmount = amount;
    }

    public void StartBenchmark() {
        GD.Print("benchmark");
        for (int x = 0; x < chunksPerX; x++) {
            for (int y = 0; y < chunksPerY; y++) {
                WritePixel<Dirt>(x * chunkResX/2, y * chunkResY/2, 100);
            }
        }
    }

    public Chunk[,] GetChunks() {
        return chunks;
    }

    private void MakeItRain() {
        if (rainAmount < .1f) return;

        int rainDrops = (int)Math.Round(rainAmount);

        for (int i = 0; i <= rainDrops; i++) {
            if (GD.Randf() < rainAmount)
                WritePixel<Water>((int)(GD.Randi() % (chunkResX * chunksPerX)), 0, 1);
        }
    }

    public void WritePixel<T>(int x, int y, int size) {
        int halfsize = size/2;

        int startPtX = x % chunkResX;
        int startPtY = y % chunkResY;

        for (int i = -halfsize; i <= halfsize; i++) {
            for (int j = -halfsize; j <= halfsize; j++) {

                // calculate in-chunk coordinates
                int iteratorX = i;
                int iteratorY = j;
                int ptX = startPtX;
                int ptY = startPtY;

                // calculate chunk to write to
                int chunkX = x/chunkResX;

                // left of chunk
                if (startPtX + iteratorX < 0) {
                    chunkX--;
                    iteratorX = chunkResX + startPtX + iteratorX;
                    ptX = startPtX + iteratorX;

                // right of chunk
                } else if (startPtX + iteratorX >= chunkResX) {
                    chunkX++;
                    ptX = startPtX + iteratorX - chunkResX;
                } else {
                    ptX = startPtX + iteratorX;
                }

                int chunkY = y/chunkResY;

                // above chunk
                if (startPtY + iteratorY < 0) {
                    chunkY--;
                    ptY = chunkResY + (startPtY + iteratorY);

                // left of chunk
                } else if (startPtY + iteratorY >= chunkResY) {
                    chunkY++;
                    ptY = iteratorY % chunkResY;
                } else {
                    ptY = startPtY + iteratorY;
                }

                // ignore everything outside
                if (chunkX < 0) continue;
                if (chunkX > chunksPerX) continue;
                if (chunkY < 0) continue;
                if (chunkY > chunksPerY) continue;

                chunks[chunkX, chunkY].WritePixel<T>(ptX, ptY);
            }
        }
    }

    public Image DrawLevel() {
        for (int cx = 0; cx < chunksPerX; cx++) {
            for (int cy = 0; cy < chunksPerY; cy++) {

                for (int x = 0; x < chunkResX; x++) {
                    for (int y = 0; y < chunkResY; y++) {
                        // TODO: multithreading here! use Chunk.DrawLevel() and stitch images together
                        image.SetPixel(cx*chunkResX + x, cy*chunkResY + y, chunks[cx,cy].Elements[x, y].Color);
                    }
                }
            }
        }
        return image;
    }
}