package main

import (
	"fmt"
	"strings"
)

// Convert rgb to uint
func Col2Uint(r, g, b byte) uint {
	return (uint(r) << 16) | (uint(g) << 8) | uint(b)
}

// Convert uint to rgb (in that order)
func Uint2Col(col uint) (byte, byte, byte) {
	return byte((col >> 16) & 0xFF), byte((col >> 8) & 0xFF), byte(col & 0xFF)
}

// Color is in ARGB (alpha not used right now)
type Framebuffer struct {
	Data   []uint
	Width  uint
	Height uint
}

// Create a new framebuffer for the given width and height.
func NewFramebuffer(width uint, height uint) Framebuffer {
	return Framebuffer{
		Data:   make([]uint, width*height),
		Width:  width,
		Height: height,
	}
}

// Sure hope this gets inlined...
func (fb *Framebuffer) Set(x uint, y uint, color uint) {
	fb.Data[x+y*fb.Width] = color
}

// Given some image data, return a string that is the ppm of it
func (fb *Framebuffer) ExportPPM() string {
	var result strings.Builder
	result.WriteString(fmt.Sprintf("P3\n%d %d\n255\n", fb.Width, fb.Height))
	for y := range fb.Height {
		for x := range fb.Width {
			r, g, b := Uint2Col(fb.Data[x+y*fb.Width])
			result.WriteString(fmt.Sprintf("%d %d %d\t", r, g, b))
		}
		result.WriteRune('\n')
	}
	return result.String()
}