From e3443d57f51af0aca96e943665e645bc87e1b63d Mon Sep 17 00:00:00 2001
From: Kistaro Windrider <kistaro@gmail.com>
Date: Sat, 9 Dec 2023 20:50:15 -0800
Subject: [PATCH] parsing

---
 apgbpal.go | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 87 insertions(+), 3 deletions(-)

diff --git a/apgbpal.go b/apgbpal.go
index d3e9e28..d469ab3 100644
--- a/apgbpal.go
+++ b/apgbpal.go
@@ -1,5 +1,11 @@
 package main
 
+import (
+	"fmt"
+	"strings"
+	"log"
+)
+
 type RGBA struct {
 	R byte
 	G byte
@@ -11,6 +17,45 @@ func (c RGBA) Bytes() [4]byte {
 	return [4]byte {c.R, c.G, cB, c.A}
 }
 
+func HexByteAt(str string, index int) (byte, error) {
+	if len(string) < index + 2 {
+		return 0, fmt.Errorf("no hex byte at %d in too short string %q", index, str)
+	}
+	big, err := strconv.ParseUint(str[index:index+1], 16, 8)
+	if err != nil {
+		return 0, fmt.Errorf("can't parse hex byte at %d in string %q: %w", index, str, err)
+	}
+	return byte(big), nil
+}
+
+func MustParseRGBA(str string) RGBA {
+	s := strings.TrimSpace(str)
+	s = strings.ToLower(s)
+	s, _ = strings.CutPrefix(s, "#")
+	var ret RGBA
+	switch len(s) {
+	case 6:
+		ret.A = 0xFF
+	case 8:
+		var err error
+		ret.A, err = HexByteAt(s, 6)
+		if err != nil {
+			log.Fatalf("can't parse alpha channel: %v", err)
+		}
+	default:
+		log.Fatalf("%q is not an RGBA value: wrong length after trimming", str)
+	}
+	if ret.R, err := HexByteAt(s, 0); err != nil {
+		log.Fatalf("can't parse red channel: %v", err)
+	}
+	if ret.G, err := HexByteAt(s, 2); err != nil {
+		log.Fatalf("can't parse green channel: %v", err)
+	}
+	if ret.B, err := HexByteAt(s, 4); err != nil {
+		log.Fatalf("can't parse blue channel: %v", err)
+	}
+}
+
 type BGPal [4]RGBA
 
 func (b BGPal) Bytes() [20]byte {
@@ -28,6 +73,20 @@ func (b BGPal) Bytes() [20]byte {
 	return ret
 }
 
+func MustParseBGPal(strs []string) BGPal {
+	if len(strs) != 4 {
+		log.Fatalf("MustParseBGPal requires length 4, got %d", len(strs))
+	}
+	var ret BGPal
+	for i := 0; i < 4; i++ {
+		ret[i], err := MustParseRGBA(strs[i])
+		if err != nil {
+			log.Fatalf("MustParseBGPal can't parse at %d: %v", i, err)
+		}
+	}
+	return ret
+}
+
 type OBJPal [3]RGBA
 
 func (o OBJPal) Bytes(indexchar byte) [18]byte {
@@ -47,12 +106,37 @@ func (o OBJPal) Bytes(indexchar byte) [18]byte {
 	return ret
 }
 
+func MustParseOBJPal {
+	if len(strs) != 3 {
+	log.Fatalf("MustParseObjPal requires length 3, got %d", len(strs))
+	}
+	var ret OBJPal
+	for i := 0; i < 3; i++ {
+		ret[i], err := MustParseRGBA(strs[i])
+		if err != nil {
+			log.Fatalf("MustParseOBJPal can't parse at %d: %v", i, err)
+		}
+	}
+	return ret
+}
+
 type APGBPal struct {
 	BG BGPal
+	OBJ0 OBJPal
 	OBJ1 OBJPal
-	OBJ2 OBJPal
 }
 
 func (a APGBPal) Bytes() [56]byte {
-	
-}
\ No newline at end of file
+	var ret [56]byte
+	for i, b := range a.BG.Bytes() {
+		ret[i] = b
+	}
+	for i, b := range a.OBJ0.Bytes('0') {
+		ret[i+20] = b
+	}
+	for i, b := range a.OBJ1.Bytes('1') {
+		ret[i+38] = b
+	}
+	return ret
+}
+