refactor(adapters): extract common helpers + fix kilo native schema

internal/adapter/common/io.go

@@ -0,0 +1,88 @@
+package common
+
+import (
+	"encoding/json"
+	"os"
+	"regexp"
+	"strings"
+
+	"github.com/lukaszraczylo/harness-sync/internal/canonical"
+)
+
+// ReadIfExists returns the file body or empty string when missing.
+func ReadIfExists(path string) (string, error) {
+	b, err := os.ReadFile(path)
+	if os.IsNotExist(err) {
+		return "", nil
+	}
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}
+
+// DirExists reports whether path is an existing directory.
+func DirExists(path string) bool {
+	info, err := os.Stat(path)
+	return err == nil && info.IsDir()
+}
+
+var (
+	blockComment = regexp.MustCompile(`(?s)/\*.*?\*/`)
+	lineComment  = regexp.MustCompile(`(?m)//[^\n]*`)
+)
+
+// StripJSONComments is a naive JSONC -> JSON stripper. It does not understand
+// strings containing // or /* and is therefore only safe for hand-edited
+// config files that don't put comment markers inside string literals.
+func StripJSONComments(s string) string {
+	s = blockComment.ReplaceAllString(s, "")
+	s = lineComment.ReplaceAllString(s, "")
+	return strings.TrimSpace(s)
+}
+
+// ImportMCPFromJSONFile reads a JSON file and extracts an MCP server map
+// nested under the given top-level key (e.g. "mcpServers", "mcp").
+// Returns nil with no error when the file is missing.
+func ImportMCPFromJSONFile(path, key string) ([]canonical.MCPServer, error) {
+	body, err := os.ReadFile(path)
+	if os.IsNotExist(err) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return ParseMCPFromJSON(body, key)
+}
+
+// ParseMCPFromJSON extracts MCP servers from a JSON body. The body may be
+// raw JSON or JSONC (comments are stripped first).
+func ParseMCPFromJSON(body []byte, key string) ([]canonical.MCPServer, error) {
+	clean := StripJSONComments(string(body))
+	var raw map[string]json.RawMessage
+	if err := json.Unmarshal([]byte(clean), &raw); err != nil {
+		return nil, nil // tolerate malformed config
+	}
+	nested, ok := raw[key]
+	if !ok {
+		return nil, nil
+	}
+	var entries map[string]struct { //nolint:govet // fieldalignment: map+slice+3 strings irreducible
+		Env       map[string]string `json:"env"`
+		Args      []string          `json:"args"`
+		Command   string            `json:"command"`
+		URL       string            `json:"url"`
+		Transport string            `json:"transport"`
+	}
+	if err := json.Unmarshal(nested, &entries); err != nil {
+		return nil, nil
+	}
+	out := make([]canonical.MCPServer, 0, len(entries))
+	for n, v := range entries {
+		out = append(out, canonical.MCPServer{
+			Name: n, Command: v.Command, Args: v.Args, URL: v.URL,
+			Transport: v.Transport, Env: v.Env,
+		})
+	}
+	return out, nil
+}