package tools

import "tui-ascii-mapper/internal/model"

func Brush(m *model.Map, center model.Point, terrain int, size int, palette []model.Terrain) {
	half := size / 2
	for dy := -half; dy <= half; dy++ {
		for dx := -half; dx <= half; dx++ {
			color := ""
			if terrain >= 0 && terrain < len(palette) {
				color = palette[terrain].PickColor()
			}
			m.SetCell(model.Point{X: center.X + dx, Y: center.Y + dy}, terrain, color)
		}
	}
}

func ThickenPoints(pts []model.Point, size int) []model.Point {
	if size <= 1 {
		return pts
	}
	half := size / 2
	seen := make(map[model.Point]bool)
	var result []model.Point
	for _, p := range pts {
		for dy := -half; dy <= half; dy++ {
			for dx := -half; dx <= half; dx++ {
				np := model.Point{X: p.X + dx, Y: p.Y + dy}
				if !seen[np] {
					seen[np] = true
					result = append(result, np)
				}
			}
		}
	}
	return result
}

func FloodFill(m *model.Map, start model.Point, terrain int, palette []model.Terrain) {
	if !m.InBounds(start) {
		return
	}
	target := m.CellAt(start).Terrain
	if target == terrain {
		return
	}
	color := ""
	if terrain >= 0 && terrain < len(palette) {
		color = palette[terrain].PickColor()
	}
	type pt struct{ x, y int }
	stack := []pt{{start.X, start.Y}}
	visited := make([][]bool, m.Height)
	for i := range visited {
		visited[i] = make([]bool, m.Width)
	}
	for len(stack) > 0 {
		p := stack[len(stack)-1]
		stack = stack[:len(stack)-1]
		if !m.InBounds(model.Point{X: p.x, Y: p.y}) || visited[p.y][p.x] {
			continue
		}
		if m.Grid[p.y][p.x].Terrain != target {
			continue
		}
		visited[p.y][p.x] = true
		m.SetCell(model.Point{X: p.x, Y: p.y}, terrain, color)
		stack = append(stack, pt{p.x + 1, p.y}, pt{p.x - 1, p.y}, pt{p.x, p.y + 1}, pt{p.x, p.y - 1})
	}
}

func BresenhamLine(a, b model.Point) []model.Point {
	var pts []model.Point
	x0, y0 := a.X, a.Y
	x1, y1 := b.X, b.Y
	dx := iabs(x1 - x0)
	dy := -iabs(y1 - y0)
	sx, sy := 1, 1
	if x0 > x1 {
		sx = -1
	}
	if y0 > y1 {
		sy = -1
	}
	err := dx + dy
	for {
		pts = append(pts, model.Point{X: x0, Y: y0})
		if x0 == x1 && y0 == y1 {
			break
		}
		e2 := 2 * err
		if e2 >= dy {
			err += dy
			x0 += sx
		}
		if e2 <= dx {
			err += dx
			y0 += sy
		}
	}
	return pts
}

func iabs(x int) int {
	if x < 0 {
		return -x
	}
	return x
}

func DrawRect(a, b model.Point, filled bool) []model.Point {
	x0, x1 := a.X, b.X
	y0, y1 := a.Y, b.Y
	if x0 > x1 {
		x0, x1 = x1, x0
	}
	if y0 > y1 {
		y0, y1 = y1, y0
	}
	var pts []model.Point
	if filled {
		for y := y0; y <= y1; y++ {
			for x := x0; x <= x1; x++ {
				pts = append(pts, model.Point{X: x, Y: y})
			}
		}
		return pts
	}
	for x := x0; x <= x1; x++ {
		pts = append(pts, model.Point{X: x, Y: y0}, model.Point{X: x, Y: y1})
	}
	for y := y0 + 1; y < y1; y++ {
		pts = append(pts, model.Point{X: x0, Y: y}, model.Point{X: x1, Y: y})
	}
	return pts
}

func DrawCircle(center, edge model.Point, filled bool) []model.Point {
	r2 := (edge.X-center.X)*(edge.X-center.X) + (edge.Y-center.Y)*(edge.Y-center.Y)
	r := r2
	if r < 0 {
		return nil
	}
	radius := IntSqrt(r)
	var pts []model.Point
	for dy := -radius; dy <= radius; dy++ {
		for dx := -radius; dx <= radius; dx++ {
			dist2 := dx*dx + dy*dy
			if filled {
				if dist2 <= r {
					pts = append(pts, model.Point{X: center.X + dx, Y: center.Y + dy})
				}
			} else {
				if dist2 <= r && dist2 > (radius-1)*(radius-1) {
					pts = append(pts, model.Point{X: center.X + dx, Y: center.Y + dy})
				}
			}
		}
	}
	return pts
}

func DrawOval(f1, f2 model.Point, filled bool) []model.Point {
	dx := f2.X - f1.X
	dy := f2.Y - f1.Y
	dist := IntSqrt(dx*dx + dy*dy)
	if dist == 0 {
		return nil
	}
	a := dist * 3 / 2
	if a < 1 {
		a = 1
	}
	a2 := a * a
	c2 := dist * dist / 4
	b2 := a2 - c2
	if b2 < 0 {
		b2 = 0
	}

	cx := (f1.X + f2.X) / 2
	cy := (f1.Y + f2.Y) / 2

	minX := cx - a - 1
	maxX := cx + a + 1
	minY := cy - a - 1
	maxY := cy + a + 1

	var pts []model.Point
	for py := minY; py <= maxY; py++ {
		for px := minX; px <= maxX; px++ {
			d1 := distSq(px, py, f1.X, f1.Y)
			d2 := distSq(px, py, f2.X, f2.Y)
			sum := IntSqrt(d1) + IntSqrt(d2)

			if filled {
				if sum <= 2*a {
					pts = append(pts, model.Point{X: px, Y: py})
				}
			} else {
				if sum >= 2*a-1 && sum <= 2*a+1 {
					pts = append(pts, model.Point{X: px, Y: py})
				}
			}
		}
	}
	return pts
}

func distSq(x1, y1, x2, y2 int) int {
	dx := x1 - x2
	dy := y1 - y2
	return dx*dx + dy*dy
}

func IntSqrt(n int) int {
	if n <= 0 {
		return 0
	}
	lo, hi := 0, n
	for lo < hi {
		mid := (lo + hi + 1) / 2
		if mid*mid <= n {
			lo = mid
		} else {
			hi = mid - 1
		}
	}
	return lo
}

func ApplyPoints(m *model.Map, pts []model.Point, terrain int, palette []model.Terrain) {
	color := ""
	if terrain >= 0 && terrain < len(palette) {
		color = palette[terrain].PickColor()
	}
	for _, p := range pts {
		m.SetCell(p, terrain, color)
	}
}

func PlaceTextLabel(m *model.Map, start model.Point, text string, color string) {
	RemoveTextLabel(m, start)
	tl := model.TextLabel{Text: text, Start: start, Color: color}
	m.TextLabels = append(m.TextLabels, tl)
	runes := []rune(text)
	for i, r := range runes {
		p := model.Point{X: start.X + i, Y: start.Y}
		if m.InBounds(p) {
			m.Grid[p.Y][p.X].Text = string(r)
		}
	}
}

func RemoveTextLabel(m *model.Map, start model.Point) {
	for i, tl := range m.TextLabels {
		if tl.Start == start {
			m.TextLabels = append(m.TextLabels[:i], m.TextLabels[i+1:]...)
			break
		}
	}
	for y := range m.Grid {
		for x := range m.Grid[y] {
			if m.Grid[y][x].Text == "" {
				continue
			}
			found := false
			for _, tl := range m.TextLabels {
				runes := []rune(tl.Text)
				for i := range runes {
					if tl.Start.X+i == x && tl.Start.Y == y {
						found = true
						break
					}
				}
				if found {
					break
				}
			}
			if !found {
				m.Grid[y][x].Text = ""
			}
		}
	}
}

func FindTextLabelAt(m *model.Map, p model.Point) int {
	for i, tl := range m.TextLabels {
		runes := []rune(tl.Text)
		for j := range runes {
			if tl.Start.X+j == p.X && tl.Start.Y == p.Y {
				return i
			}
		}
	}
	return -1
}

func MoveTextLabel(m *model.Map, oldStart, newStart model.Point) {
	for i, tl := range m.TextLabels {
		if tl.Start == oldStart {
			for _, p := range LabelPositions(tl) {
				if m.InBounds(p) {
					m.Grid[p.Y][p.X].Text = ""
				}
			}
			m.TextLabels[i].Start = newStart
			runes := []rune(tl.Text)
			for j, r := range runes {
				p := model.Point{X: newStart.X + j, Y: newStart.Y}
				if m.InBounds(p) {
					m.Grid[p.Y][p.X].Text = string(r)
				}
			}
			return
		}
	}
}

func LabelPositions(tl model.TextLabel) []model.Point {
	var pts []model.Point
	runes := []rune(tl.Text)
	for i := range runes {
		pts = append(pts, model.Point{X: tl.Start.X + i, Y: tl.Start.Y})
	}
	return pts
}