package ru.dbotthepony.kstarbound.world

import ru.dbotthepony.kstarbound.world.api.CHUNK_SIZE
import ru.dbotthepony.kstarbound.world.api.IChunk
import ru.dbotthepony.kstarbound.world.api.IChunkCell
import ru.dbotthepony.kstarbound.world.api.ITileAccess
import ru.dbotthepony.kstarbound.world.api.ITileState
import ru.dbotthepony.kvector.vector.Vector2i

fun IChunk.iterate(fromX: Int = 0, fromY: Int = 0, toX: Int = fromX + CHUNK_SIZE, toY: Int = fromY + CHUNK_SIZE): Iterator<Pair<Vector2i, IChunkCell>> {
	return object : Iterator<Pair<Vector2i, IChunkCell>> {
		private var x = fromX
		private var y = fromY

		override fun hasNext(): Boolean {
			return x < toX && y < toY
		}

		override fun next(): Pair<Vector2i, IChunkCell> {
			if (!hasNext())
				throw NoSuchElementException()

			val tile = getCell(x, y)
			val pos = Vector2i(x, y)

			x++

			if (x >= toX) {
				y++
				x = 0
			}

			return pos to tile
		}
	}
}

fun ITileAccess.iterateTiles(fromX: Int = 0, fromY: Int = 0, toX: Int = fromX + CHUNK_SIZE, toY: Int = fromY + CHUNK_SIZE): Iterator<Pair<Vector2i, ITileState>> {
	return object : Iterator<Pair<Vector2i, ITileState>> {
		private var x = fromX
		private var y = fromY

		override fun hasNext(): Boolean {
			return x < toX && y < toY
		}

		override fun next(): Pair<Vector2i, ITileState> {
			if (!hasNext())
				throw NoSuchElementException()

			val tile = getTile(x, y)
			val pos = Vector2i(x, y)

			x++

			if (x >= toX) {
				y++
				x = 0
			}

			return pos to tile
		}
	}
}