package d2grid

import (
	"strconv"

	"oss.terrastruct.com/d2/d2graph"
)

type grid struct {
	root    *d2graph.Object
	nodes   []*d2graph.Object
	rows    int
	columns int

	width  float64
	height float64
}

func newGrid(root *d2graph.Object) *grid {
	g := grid{root: root, nodes: root.ChildrenArray}
	if root.Attributes.Rows != nil {
		g.rows, _ = strconv.Atoi(root.Attributes.Rows.Value)
	}
	if root.Attributes.Columns != nil {
		g.columns, _ = strconv.Atoi(root.Attributes.Columns.Value)
	}

	// compute exact row/column count based on values entered
	// TODO consider making this based on node dimensions
	if g.rows == 0 {
		// set rows based on number of columns
		g.rows = len(g.nodes) / g.columns
		if len(g.nodes)%g.columns != 0 {
			g.rows++
		}
	} else if g.columns == 0 {
		// set columns based on number of rows
		g.columns = len(g.nodes) / g.rows
		if len(g.nodes)%g.rows != 0 {
			g.columns++
		}
	} else {
		// rows and columns specified (add more rows if needed)
		capacity := g.rows * g.columns
		for capacity < len(g.nodes) {
			g.rows++
			capacity += g.columns
		}
	}

	return &g
}

func (g *grid) shift(dx, dy float64) {
	for _, obj := range g.nodes {
		obj.TopLeft.X += dx
		obj.TopLeft.Y += dy
	}
}