package display

import "github.com/veandco/go-sdl2/sdl"

// Bitmap font: 5x7 pixel glyphs for ASCII 32–126, rendered via FillRect.
// Each glyph is 7 rows of 5 bits (MSB = leftmost pixel).

const (
	glyphW  = 5 // pixels per character width
	glyphH  = 7 // pixels per character height
	charGap = 1 // horizontal gap between characters
)

// font5x7 maps ASCII 32–126 to 7-byte bitmaps (one byte per row, top 5 bits used).
// Index 0 = space (0x20), index 94 = tilde (0x7E).
var font5x7 = [95][7]byte{
	// space (0x20)
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
	// ! (0x21)
	{0x20, 0x20, 0x20, 0x20, 0x20, 0x00, 0x20},
	// " (0x22)
	{0x50, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00},
	// # (0x23)
	{0x50, 0xF8, 0x50, 0x50, 0x50, 0xF8, 0x50},
	// $ (0x24)
	{0x20, 0x70, 0xA0, 0x70, 0x28, 0x70, 0x20},
	// % (0x25)
	{0xC8, 0xC8, 0x10, 0x20, 0x40, 0x98, 0x98},
	// & (0x26)
	{0x40, 0xA0, 0xA0, 0x40, 0xA8, 0x90, 0x68},
	// ' (0x27)
	{0x20, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00},
	// ( (0x28)
	{0x10, 0x20, 0x40, 0x40, 0x40, 0x20, 0x10},
	// ) (0x29)
	{0x40, 0x20, 0x10, 0x10, 0x10, 0x20, 0x40},
	// * (0x2A)
	{0x00, 0x20, 0xA8, 0x70, 0xA8, 0x20, 0x00},
	// + (0x2B)
	{0x00, 0x20, 0x20, 0xF8, 0x20, 0x20, 0x00},
	// , (0x2C)
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x40},
	// - (0x2D)
	{0x00, 0x00, 0x00, 0xF8, 0x00, 0x00, 0x00},
	// . (0x2E)
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20},
	// / (0x2F)
	{0x08, 0x08, 0x10, 0x20, 0x40, 0x80, 0x80},
	// 0 (0x30)
	{0x70, 0x88, 0x98, 0xA8, 0xC8, 0x88, 0x70},
	// 1 (0x31)
	{0x20, 0x60, 0x20, 0x20, 0x20, 0x20, 0x70},
	// 2 (0x32)
	{0x70, 0x88, 0x08, 0x10, 0x20, 0x40, 0xF8},
	// 3 (0x33)
	{0x70, 0x88, 0x08, 0x30, 0x08, 0x88, 0x70},
	// 4 (0x34)
	{0x10, 0x30, 0x50, 0x90, 0xF8, 0x10, 0x10},
	// 5 (0x35)
	{0xF8, 0x80, 0xF0, 0x08, 0x08, 0x88, 0x70},
	// 6 (0x36)
	{0x30, 0x40, 0x80, 0xF0, 0x88, 0x88, 0x70},
	// 7 (0x37)
	{0xF8, 0x08, 0x10, 0x20, 0x40, 0x40, 0x40},
	// 8 (0x38)
	{0x70, 0x88, 0x88, 0x70, 0x88, 0x88, 0x70},
	// 9 (0x39)
	{0x70, 0x88, 0x88, 0x78, 0x08, 0x10, 0x60},
	// : (0x3A)
	{0x00, 0x00, 0x20, 0x00, 0x00, 0x20, 0x00},
	// ; (0x3B)
	{0x00, 0x00, 0x20, 0x00, 0x00, 0x20, 0x40},
	// < (0x3C)
	{0x08, 0x10, 0x20, 0x40, 0x20, 0x10, 0x08},
	// = (0x3D)
	{0x00, 0x00, 0xF8, 0x00, 0xF8, 0x00, 0x00},
	// > (0x3E)
	{0x80, 0x40, 0x20, 0x10, 0x20, 0x40, 0x80},
	// ? (0x3F)
	{0x70, 0x88, 0x08, 0x10, 0x20, 0x00, 0x20},
	// @ (0x40)
	{0x70, 0x88, 0xB8, 0xA8, 0xB8, 0x80, 0x70},
	// A (0x41)
	{0x70, 0x88, 0x88, 0xF8, 0x88, 0x88, 0x88},
	// B (0x42)
	{0xF0, 0x88, 0x88, 0xF0, 0x88, 0x88, 0xF0},
	// C (0x43)
	{0x70, 0x88, 0x80, 0x80, 0x80, 0x88, 0x70},
	// D (0x44)
	{0xF0, 0x88, 0x88, 0x88, 0x88, 0x88, 0xF0},
	// E (0x45)
	{0xF8, 0x80, 0x80, 0xF0, 0x80, 0x80, 0xF8},
	// F (0x46)
	{0xF8, 0x80, 0x80, 0xF0, 0x80, 0x80, 0x80},
	// G (0x47)
	{0x70, 0x88, 0x80, 0xB8, 0x88, 0x88, 0x70},
	// H (0x48)
	{0x88, 0x88, 0x88, 0xF8, 0x88, 0x88, 0x88},
	// I (0x49)
	{0x70, 0x20, 0x20, 0x20, 0x20, 0x20, 0x70},
	// J (0x4A)
	{0x38, 0x10, 0x10, 0x10, 0x10, 0x90, 0x60},
	// K (0x4B)
	{0x88, 0x90, 0xA0, 0xC0, 0xA0, 0x90, 0x88},
	// L (0x4C)
	{0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0xF8},
	// M (0x4D)
	{0x88, 0xD8, 0xA8, 0xA8, 0x88, 0x88, 0x88},
	// N (0x4E)
	{0x88, 0xC8, 0xA8, 0x98, 0x88, 0x88, 0x88},
	// O (0x4F)
	{0x70, 0x88, 0x88, 0x88, 0x88, 0x88, 0x70},
	// P (0x50)
	{0xF0, 0x88, 0x88, 0xF0, 0x80, 0x80, 0x80},
	// Q (0x51)
	{0x70, 0x88, 0x88, 0x88, 0xA8, 0x90, 0x68},
	// R (0x52)
	{0xF0, 0x88, 0x88, 0xF0, 0xA0, 0x90, 0x88},
	// S (0x53)
	{0x70, 0x88, 0x80, 0x70, 0x08, 0x88, 0x70},
	// T (0x54)
	{0xF8, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20},
	// U (0x55)
	{0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x70},
	// V (0x56)
	{0x88, 0x88, 0x88, 0x88, 0x88, 0x50, 0x20},
	// W (0x57)
	{0x88, 0x88, 0x88, 0xA8, 0xA8, 0xD8, 0x88},
	// X (0x58)
	{0x88, 0x88, 0x50, 0x20, 0x50, 0x88, 0x88},
	// Y (0x59)
	{0x88, 0x88, 0x50, 0x20, 0x20, 0x20, 0x20},
	// Z (0x5A)
	{0xF8, 0x08, 0x10, 0x20, 0x40, 0x80, 0xF8},
	// [ (0x5B)
	{0x70, 0x40, 0x40, 0x40, 0x40, 0x40, 0x70},
	// \ (0x5C)
	{0x80, 0x80, 0x40, 0x20, 0x10, 0x08, 0x08},
	// ] (0x5D)
	{0x70, 0x10, 0x10, 0x10, 0x10, 0x10, 0x70},
	// ^ (0x5E)
	{0x20, 0x50, 0x88, 0x00, 0x00, 0x00, 0x00},
	// _ (0x5F)
	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF8},
	// ` (0x60)
	{0x40, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00},
	// a (0x61)
	{0x00, 0x00, 0x70, 0x08, 0x78, 0x88, 0x78},
	// b (0x62)
	{0x80, 0x80, 0xF0, 0x88, 0x88, 0x88, 0xF0},
	// c (0x63)
	{0x00, 0x00, 0x70, 0x80, 0x80, 0x80, 0x70},
	// d (0x64)
	{0x08, 0x08, 0x78, 0x88, 0x88, 0x88, 0x78},
	// e (0x65)
	{0x00, 0x00, 0x70, 0x88, 0xF8, 0x80, 0x70},
	// f (0x66)
	{0x30, 0x48, 0x40, 0xE0, 0x40, 0x40, 0x40},
	// g (0x67)
	{0x00, 0x00, 0x78, 0x88, 0x78, 0x08, 0x70},
	// h (0x68)
	{0x80, 0x80, 0xF0, 0x88, 0x88, 0x88, 0x88},
	// i (0x69)
	{0x20, 0x00, 0x60, 0x20, 0x20, 0x20, 0x70},
	// j (0x6A)
	{0x10, 0x00, 0x30, 0x10, 0x10, 0x90, 0x60},
	// k (0x6B)
	{0x80, 0x80, 0x90, 0xA0, 0xC0, 0xA0, 0x90},
	// l (0x6C)
	{0x60, 0x20, 0x20, 0x20, 0x20, 0x20, 0x70},
	// m (0x6D)
	{0x00, 0x00, 0xD0, 0xA8, 0xA8, 0xA8, 0xA8},
	// n (0x6E)
	{0x00, 0x00, 0xF0, 0x88, 0x88, 0x88, 0x88},
	// o (0x6F)
	{0x00, 0x00, 0x70, 0x88, 0x88, 0x88, 0x70},
	// p (0x70)
	{0x00, 0x00, 0xF0, 0x88, 0xF0, 0x80, 0x80},
	// q (0x71)
	{0x00, 0x00, 0x78, 0x88, 0x78, 0x08, 0x08},
	// r (0x72)
	{0x00, 0x00, 0xB0, 0xC8, 0x80, 0x80, 0x80},
	// s (0x73)
	{0x00, 0x00, 0x78, 0x80, 0x70, 0x08, 0xF0},
	// t (0x74)
	{0x40, 0x40, 0xE0, 0x40, 0x40, 0x48, 0x30},
	// u (0x75)
	{0x00, 0x00, 0x88, 0x88, 0x88, 0x88, 0x78},
	// v (0x76)
	{0x00, 0x00, 0x88, 0x88, 0x88, 0x50, 0x20},
	// w (0x77)
	{0x00, 0x00, 0x88, 0x88, 0xA8, 0xA8, 0x50},
	// x (0x78)
	{0x00, 0x00, 0x88, 0x50, 0x20, 0x50, 0x88},
	// y (0x79)
	{0x00, 0x00, 0x88, 0x88, 0x78, 0x08, 0x70},
	// z (0x7A)
	{0x00, 0x00, 0xF8, 0x10, 0x20, 0x40, 0xF8},
	// { (0x7B)
	{0x10, 0x20, 0x20, 0x40, 0x20, 0x20, 0x10},
	// | (0x7C)
	{0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20},
	// } (0x7D)
	{0x40, 0x20, 0x20, 0x10, 0x20, 0x20, 0x40},
	// ~ (0x7E)
	{0x00, 0x00, 0x40, 0xA8, 0x10, 0x00, 0x00},
}

// drawChar renders a single ASCII character at (x, y) using filled rectangles.
// Each pixel of the 5x7 glyph is drawn as a scale×scale block.
func drawChar(renderer *sdl.Renderer, ch byte, x, y, scale int32) {
	if ch < 0x20 || ch > 0x7E {
		ch = '?' // replace unprintable characters
	}
	glyph := font5x7[ch-0x20]
	for row := 0; row < glyphH; row++ {
		bits := glyph[row]
		for col := 0; col < glyphW; col++ {
			if bits&(0x80>>uint(col)) != 0 {
				renderer.FillRect(&sdl.Rect{
					X: x + int32(col)*scale,
					Y: y + int32(row)*scale,
					W: scale,
					H: scale,
				})
			}
		}
	}
}

// drawString renders a string at (x, y) with the given pixel scale.
// Returns the total width in pixels consumed by the string.
func drawString(renderer *sdl.Renderer, s string, x, y, scale int32) int32 {
	cx := x
	for i := 0; i < len(s); i++ {
		drawChar(renderer, s[i], cx, y, scale)
		cx += (glyphW + charGap) * scale
	}
	return cx - x
}

// stringWidth returns the pixel width of a string at the given scale.
func stringWidth(s string, scale int32) int32 {
	if len(s) == 0 {
		return 0
	}
	return int32(len(s))*(glyphW+charGap)*scale - charGap*scale
}