feat: default system theme (#419)

Co-authored-by: adamdottv <[email protected]>

1 files changed, 93 insertions, 0 deletions

diff --git a/packages/tui/internal/util/color.go b/packages/tui/internal/util/color.go
new file mode 100644
index 000000000..f0d73bcb2
--- /dev/null
+++ b/packages/tui/internal/util/color.go
@@ -0,0 +1,93 @@
+package util
+
+import (
+	"regexp"
+	"strings"
+)
+
+var csiRE *regexp.Regexp
+
+func init() {
+	csiRE = regexp.MustCompile(`\x1b\[([0-9;]+)m`)
+}
+
+var targetFGMap = map[string]string{
+	"0;0;0":       "\x1b[30m", // Black
+	"128;0;0":     "\x1b[31m", // Red
+	"0;128;0":     "\x1b[32m", // Green
+	"128;128;0":   "\x1b[33m", // Yellow
+	"0;0;128":     "\x1b[34m", // Blue
+	"128;0;128":   "\x1b[35m", // Magenta
+	"0;128;128":   "\x1b[36m", // Cyan
+	"192;192;192": "\x1b[37m", // White (light grey)
+	"128;128;128": "\x1b[90m", // Bright Black (dark grey)
+	"255;0;0":     "\x1b[91m", // Bright Red
+	"0;255;0":     "\x1b[92m", // Bright Green
+	"255;255;0":   "\x1b[93m", // Bright Yellow
+	"0;0;255":     "\x1b[94m", // Bright Blue
+	"255;0;255":   "\x1b[95m", // Bright Magenta
+	"0;255;255":   "\x1b[96m", // Bright Cyan
+	"255;255;255": "\x1b[97m", // Bright White
+}
+
+var targetBGMap = map[string]string{
+	"0;0;0":       "\x1b[40m",
+	"128;0;0":     "\x1b[41m",
+	"0;128;0":     "\x1b[42m",
+	"128;128;0":   "\x1b[43m",
+	"0;0;128":     "\x1b[44m",
+	"128;0;128":   "\x1b[45m",
+	"0;128;128":   "\x1b[46m",
+	"192;192;192": "\x1b[47m",
+	"128;128;128": "\x1b[100m",
+	"255;0;0":     "\x1b[101m",
+	"0;255;0":     "\x1b[102m",
+	"255;255;0":   "\x1b[103m",
+	"0;0;255":     "\x1b[104m",
+	"255;0;255":   "\x1b[105m",
+	"0;255;255":   "\x1b[106m",
+	"255;255;255": "\x1b[107m",
+}
+
+func ConvertRGBToAnsi16Colors(s string) string {
+	return csiRE.ReplaceAllStringFunc(s, func(seq string) string {
+		params := strings.Split(csiRE.FindStringSubmatch(seq)[1], ";")
+		out := make([]string, 0, len(params))
+
+		for i := 0; i < len(params); {
+			// Detect “38 | 48 ; 2 ; r ; g ; b ( ; alpha? )”
+			if (params[i] == "38" || params[i] == "48") &&
+				i+4 < len(params) &&
+				params[i+1] == "2" {
+
+				key := strings.Join(params[i+2:i+5], ";")
+				var repl string
+				if params[i] == "38" {
+					repl = targetFGMap[key]
+				} else {
+					repl = targetBGMap[key]
+				}
+
+				if repl != "" { // exact RGB hit
+					out = append(out, repl[2:len(repl)-1])
+					i += 5 // skip 38/48;2;r;g;b
+
+					// if i == len(params)-1 && looksLikeByte(params[i]) {
+					// 	i++ // swallow the alpha byte
+					// }
+					continue
+				}
+			}
+			// Normal token — keep verbatim.
+			out = append(out, params[i])
+			i++
+		}
+
+		return "\x1b[" + strings.Join(out, ";") + "m"
+	})
+}
+
+// func looksLikeByte(tok string) bool {
+// 	v, err := strconv.Atoi(tok)
+// 	return err == nil && v >= 0 && v <= 255
+// }