config: add config package and wire it into server and handlers

Replace the hardcoded server.Config with an ini-backed config package
that reads /etc/openstore/openstore.conf then the user's config file, so
user settings override system ones and both override the built-in
defaults. Missing files are ignored rather than fatal.

Move route registration into a handlers package that owns the templates
and builds a Page view model, which removes the server -> handlers
import cycle along with the setter-based context injection.

1 files changed, 73 insertions, 0 deletions

diff --git a/internal/config/config.go b/internal/config/config.go
new file mode 100644
index 0000000..2be9dd6
--- /dev/null
+++ b/internal/config/config.go
@@ -0,0 +1,73 @@
+package config
+
+import (
+	"fmt"
+	"net/url"
+	"os"
+	"path/filepath"
+
+	"gopkg.in/ini.v1"
+)
+
+type Serve struct {
+	Addr string `ini:"addr"`
+}
+
+type Instance struct {
+	Name         string `ini:"name"`
+	ContactEmail string `ini:"contact-email"`
+	BaseURL      string `ini:"base-url"`
+}
+
+type Config struct {
+	Serve    Serve    `ini:"serve"`
+	Instance Instance `ini:"instance"`
+}
+
+var systemConfigPath = "/etc/openstore/openstore.conf"
+
+func DefaultPath() (string, error) {
+	dir, err := os.UserConfigDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "openstore", "openstore.conf"), nil
+}
+
+func Load(filename string) (*Config, error) {
+	cfg, err := ini.LoadSources(ini.LoadOptions{
+		Loose:              true,
+		KeyValueDelimiters: "=",
+	}, systemConfigPath, filename)
+
+	if err != nil {
+		return nil, err
+	}
+
+	config := &Config{
+		Serve: Serve{
+			Addr: ":3000",
+		},
+		Instance: Instance{
+			Name:         "Openstore",
+			ContactEmail: "jane@doe.com",
+			BaseURL:      "https://www.example.com",
+		},
+	}
+
+	err = cfg.MapTo(config)
+	if err != nil {
+		return nil, err
+	}
+
+	u, err := url.Parse(config.Instance.BaseURL)
+	if err != nil || u.Host == "" || u.Scheme == "" {
+		return nil, fmt.Errorf(
+			"config: base-url must be an absolute url, got %s",
+			config.Instance.BaseURL,
+		)
+	}
+
+	return config, nil
+}