1 files changed, 69 insertions, 0 deletions
diff --git a/internal/hexaiaction/parse.go b/internal/hexaiaction/parse.go
new file mode 100644
index 0000000..99e2b24
--- /dev/null
+++ b/internal/hexaiaction/parse.go
@@ -0,0 +1,69 @@
+package hexaiaction
+
+import (
+    "bufio"
+    "io"
+    "strings"
+
+    "codeberg.org/snonux/hexai/internal/textutil"
+)
+
+// ParseInput splits raw stdin into optional diagnostics and selection/code.
+// Format:
+//
+//	Diagnostics:\n
+//	<one per line>\n
+//	<blank line> (optional)\n
+//	<rest is selection/code>
+//
+// If the header is absent, the entire input is treated as selection.
+func ParseInput(r io.Reader) (InputParts, error) {
+	b, err := io.ReadAll(bufio.NewReader(r))
+	if err != nil {
+		return InputParts{}, err
+	}
+	raw := strings.TrimSpace(string(b))
+	if raw == "" {
+		return InputParts{Selection: ""}, nil
+	}
+	lines := strings.Split(raw, "\n")
+	// find a case-insensitive line equal to "diagnostics:"
+	diagsIdx := -1
+	for i, ln := range lines {
+		t := strings.TrimSpace(strings.ToLower(ln))
+		if t == "diagnostics:" {
+			diagsIdx = i
+			break
+		}
+	}
+	if diagsIdx < 0 {
+		return InputParts{Selection: raw}, nil
+	}
+	// collect diagnostics until a blank line or EOF
+	diags := []string{}
+	i := diagsIdx + 1
+	for ; i < len(lines); i++ {
+		t := strings.TrimSpace(lines[i])
+		if t == "" {
+			i++
+			break
+		}
+		diags = append(diags, t)
+	}
+	sel := strings.Join(lines[i:], "\n")
+	sel = strings.TrimSpace(sel)
+	return InputParts{Selection: sel, Diagnostics: diags}, nil
+}
+
+// ExtractInstruction mirrors the LSP instructionFromSelection behavior (subset),
+// scanning the first line for an instruction marker and removing it from the selection.
+func ExtractInstruction(sel string) (string, string) { return textutil.InstructionFromSelection(sel) }
+
+// findFirstInstructionInLine follows the same precedence as LSP:
+// - ;text; (strict)
+// - /* text */ (single-line)
+// - <!-- text --> (single-line)
+// - // text
+// - # text
+// - -- text
+// helpers moved to textutil