package door

import "strings"

// I used iconv in door++, but it was horrible.  It doesn't translate
// control codes to Unicode.

// This converts CP437 to Unicode for rendering in Unicode terminals
// like the linux telnet client.
// This does everything but: \x07, \x08, \x0a and \x0d.
// 0x07, 0x08, 0x09, 0x0a, 0x0c, 0x0d, 0x1b (ANSI spec)
func CP437_to_Unicode(cp437 string) string {
	// var result string
	var result strings.Builder
	// make initial guess on capacity
	result.Grow(len(cp437))

	for _, char := range []byte(cp437) {
		// for _, char := range []rune(cp437) {
		switch int(char) {
		case 0x01:
			result.WriteRune('\u263A')
		case 0x02:
			result.WriteRune('\u263B')
		case 0x03:
			result.WriteRune('\u2665')
		case 0x04:
			result.WriteRune('\u2666')
		case 0x05:
			result.WriteRune('\u2663')
		case 0x06:
			result.WriteRune('\u2660')
		case 0x09:
			result.WriteRune('\u25CB')
		case 0x0b:
			result.WriteRune('\u2642')
		case 0x0c:
			result.WriteRune('\u2640')
		case 0x0e:
			result.WriteRune('\u266B')
		case 0x0f:
			result.WriteRune('\u263C')
		case 0x10:
			result.WriteRune('\u25BA')
		case 0x11:
			result.WriteRune('\u25C4')
		case 0x12:
			result.WriteRune('\u2195')
		case 0x13:
			result.WriteRune('\u203C')
		case 0x14:
			result.Write([]byte{0xc2, 0xb6})
		case 0x15:
			result.Write([]byte{0xc2, 0xa7})
		case 0x16:
			result.WriteRune('\u25AC')
		case 0x17:
			result.WriteRune('\u21A8')
		case 0x18:
			result.WriteRune('\u2191')
		case 0x19:
			result.WriteRune('\u2193')
		case 0x1a:
			result.WriteRune('\u2192')
		case 0x1c:
			result.WriteRune('\u221F')
		case 0x1d:
			result.WriteRune('\u2194')
		case 0x1e:
			result.WriteRune('\u25B2')
		case 0x1f:
			result.WriteRune('\u25BC')
		case 0x7f:
			result.WriteRune('\u2302')
		case 0x80:
			result.Write([]byte{0xc3, 0x87})
		case 0x81:
			result.Write([]byte{0xc3, 0xbc})
		case 0x82:
			result.Write([]byte{0xc3, 0xa9})
		case 0x83:
			result.Write([]byte{0xc3, 0xa2})
		case 0x84:
			result.Write([]byte{0xc3, 0xa4})
		case 0x85:
			result.Write([]byte{0xc3, 0xa0})
		case 0x86:
			result.Write([]byte{0xc3, 0xa5})
		case 0x87:
			result.Write([]byte{0xc3, 0xa7})
		case 0x88:
			result.Write([]byte{0xc3, 0xaa})
		case 0x89:
			result.Write([]byte{0xc3, 0xab})
		case 0x8a:
			result.Write([]byte{0xc3, 0xa8})
		case 0x8b:
			result.Write([]byte{0xc3, 0xaf})
		case 0x8c:
			result.Write([]byte{0xc3, 0xae})
		case 0x8d:
			result.Write([]byte{0xc3, 0xac})
		case 0x8e:
			result.Write([]byte{0xc3, 0x84})
		case 0x8f:
			result.Write([]byte{0xc3, 0x85})
		case 0x90:
			result.Write([]byte{0xc3, 0x89})
		case 0x91:
			result.Write([]byte{0xc3, 0xa6})
		case 0x92:
			result.Write([]byte{0xc3, 0x86})
		case 0x93:
			result.Write([]byte{0xc3, 0xb4})
		case 0x94:
			result.Write([]byte{0xc3, 0xb6})
		case 0x95:
			result.Write([]byte{0xc3, 0xb2})
		case 0x96:
			result.Write([]byte{0xc3, 0xbb})
		case 0x97:
			result.Write([]byte{0xc3, 0xb9})
		case 0x98:
			result.Write([]byte{0xc3, 0xbf})
		case 0x99:
			result.Write([]byte{0xc3, 0x96})
		case 0x9a:
			result.Write([]byte{0xc3, 0x9c})
		case 0x9b:
			result.Write([]byte{0xc2, 0xa2})
		case 0x9c:
			result.Write([]byte{0xc2, 0xa3})
		case 0x9d:
			result.Write([]byte{0xc2, 0xa5})
		case 0x9e:
			result.WriteRune('\u20A7')
		case 0x9f:
			result.WriteRune('\u0192')
		case 0xa0:
			result.Write([]byte{0xc3, 0xa1})
		case 0xa1:
			result.Write([]byte{0xc3, 0xad})
		case 0xa2:
			result.Write([]byte{0xc3, 0xb3})
		case 0xa3:
			result.Write([]byte{0xc3, 0xba})
		case 0xa4:
			result.Write([]byte{0xc3, 0xb1})
		case 0xa5:
			result.Write([]byte{0xc3, 0x91})
		case 0xa6:
			result.Write([]byte{0xc2, 0xaa})
		case 0xa7:
			result.Write([]byte{0xc2, 0xba})
		case 0xa8:
			result.Write([]byte{0xc2, 0xbf})
		case 0xa9:
			result.WriteRune('\u2310')
		case 0xaa:
			result.Write([]byte{0xc2, 0xac})
		case 0xab:
			result.Write([]byte{0xc2, 0xbd})
		case 0xac:
			result.Write([]byte{0xc2, 0xbc})
		case 0xad:
			result.Write([]byte{0xc2, 0xa1})
		case 0xae:
			result.Write([]byte{0xc2, 0xab})
		case 0xaf:
			result.Write([]byte{0xc2, 0xbb})
		case 0xb0:
			result.WriteRune('\u2591')
		case 0xb1:
			result.WriteRune('\u2592')
		case 0xb2:
			result.WriteRune('\u2593')
		case 0xb3:
			result.WriteRune('\u2502')
		case 0xb4:
			result.WriteRune('\u2524')
		case 0xb5:
			result.WriteRune('\u2561')
		case 0xb6:
			result.WriteRune('\u2562')
		case 0xb7:
			result.WriteRune('\u2556')
		case 0xb8:
			result.WriteRune('\u2555')
		case 0xb9:
			result.WriteRune('\u2563')
		case 0xba:
			result.WriteRune('\u2551')
		case 0xbb:
			result.WriteRune('\u2557')
		case 0xbc:
			result.WriteRune('\u255D')
		case 0xbd:
			result.WriteRune('\u255C')
		case 0xbe:
			result.WriteRune('\u255B')
		case 0xbf:
			result.WriteRune('\u2510')
		case 0xc0:
			result.WriteRune('\u2514')
		case 0xc1:
			result.WriteRune('\u2534')
		case 0xc2:
			result.WriteRune('\u252C')
		case 0xc3:
			result.WriteRune('\u251C')
		case 0xc4:
			result.WriteRune('\u2500')
		case 0xc5:
			result.WriteRune('\u253C')
		case 0xc6:
			result.WriteRune('\u255E')
		case 0xc7:
			result.WriteRune('\u255F')
		case 0xc8:
			result.WriteRune('\u255A')
		case 0xc9:
			result.WriteRune('\u2554')
		case 0xca:
			result.WriteRune('\u2569')
		case 0xcb:
			result.WriteRune('\u2566')
		case 0xcc:
			result.WriteRune('\u2560')
		case 0xcd:
			result.WriteRune('\u2550')
		case 0xce:
			result.WriteRune('\u256C')
		case 0xcf:
			result.WriteRune('\u2567')
		case 0xd0:
			result.WriteRune('\u2568')
		case 0xd1:
			result.WriteRune('\u2564')
		case 0xd2:
			result.WriteRune('\u2565')
		case 0xd3:
			result.WriteRune('\u2559')
		case 0xd4:
			result.WriteRune('\u2558')
		case 0xd5:
			result.WriteRune('\u2552')
		case 0xd6:
			result.WriteRune('\u2553')
		case 0xd7:
			result.WriteRune('\u256B')
		case 0xd8:
			result.WriteRune('\u256A')
		case 0xd9:
			result.WriteRune('\u2518')
		case 0xda:
			result.WriteRune('\u250C')
		case 0xdb:
			result.WriteRune('\u2588')
		case 0xdc:
			result.WriteRune('\u2584')
		case 0xdd:
			result.WriteRune('\u258C')
		case 0xde:
			result.WriteRune('\u2590')
		case 0xdf:
			result.WriteRune('\u2580')
		case 0xe0:
			result.WriteRune('\u03B1')
		case 0xe1:
			result.Write([]byte{0xc3, 0x9f})
		case 0xe2:
			result.WriteRune('\u0393')
		case 0xe3:
			result.WriteRune('\u03C0')
		case 0xe4:
			result.WriteRune('\u03A3')
		case 0xe5:
			result.WriteRune('\u03C3')
		case 0xe6:
			result.Write([]byte{0xc2, 0xb5})
		case 0xe7:
			result.WriteRune('\u03C4')
		case 0xe8:
			result.WriteRune('\u03A6')
		case 0xe9:
			result.WriteRune('\u0398')
		case 0xea:
			result.WriteRune('\u03A9')
		case 0xeb:
			result.WriteRune('\u03B4')
		case 0xec:
			result.WriteRune('\u221E')
		case 0xed:
			result.WriteRune('\u03C6')
		case 0xee:
			result.WriteRune('\u03B5')
		case 0xef:
			result.WriteRune('\u2229')
		case 0xf0:
			result.WriteRune('\u2261')
		case 0xf1:
			result.Write([]byte{0xc2, 0xb1})
		case 0xf2:
			result.WriteRune('\u2265')
		case 0xf3:
			result.WriteRune('\u2264')
		case 0xf4:
			result.WriteRune('\u2320')
		case 0xf5:
			result.WriteRune('\u2321')
		case 0xf6:
			result.Write([]byte{0xc3, 0xb7})
		case 0xf7:
			result.WriteRune('\u2248')
		case 0xf8:
			result.Write([]byte{0xc2, 0xb0})
		case 0xf9:
			result.WriteRune('\u2219')
		case 0xfa:
			result.Write([]byte{0xc2, 0xb7})
		case 0xfb:
			result.WriteRune('\u221A')
		case 0xfc:
			result.WriteRune('\u207F')
		case 0xfd:
			result.Write([]byte{0xc2, 0xb2})
		case 0xfe:
			result.WriteRune('\u25A0')
		case 0xff:
			result.Write([]byte{0xc2, 0xa0})
		default:
			result.WriteByte(byte(char))
		}
	}
	return result.String()
}