1 files changed, 73 insertions, 0 deletions
diff --git a/internal/service/config.go b/internal/service/config.go
new file mode 100644
index 0000000..bcb9efc
--- /dev/null
+++ b/internal/service/config.go
@@ -0,0 +1,73 @@
+package service
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"time"
+
+	"dario.cat/mergo"
+)
+
+type Duration struct {
+	time.Duration
+}
+
+func (s Duration) MarshalJSON() ([]byte, error) {
+	return json.Marshal(s.Duration.String())
+}
+
+func (s *Duration) UnmarshalJSON(data []byte) error {
+	var str string
+	err := json.Unmarshal(data, &str)
+	if err != nil {
+		return err
+	}
+
+	v, err := time.ParseDuration(str)
+	if err != nil {
+		return err
+	}
+	*s = Duration{v}
+
+	return nil
+}
+
+type Config struct {
+	MaxInterval Duration  `json:"max-interval,omitempty"`
+	MinInterval Duration  `json:"min-interval,omitempty"`
+	Mirrors     []*Mirror `json:"mirrors,omitempty"`
+}
+
+var DefaultConfig = Config{
+	MaxInterval: Duration{24 * time.Hour},
+	MinInterval: Duration{time.Hour},
+}
+
+func (c *Config) Apply(arg Config) {
+	err := mergo.Merge(c, &arg)
+	if err != nil {
+		panic(err)
+	}
+}
+
+// ApplyFileConfig loads the configuration described by the given yaml file.
+func ApplyFileConfig(cfg *Config, filePath string) error {
+	var ret Config
+
+	f, err := os.Open(filePath)
+	if os.IsNotExist(err) {
+		return nil
+	} else if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	err = json.NewDecoder(f).Decode(&ret)
+	if err != nil {
+		return fmt.Errorf("loading configuration file: %w", err)
+	}
+
+	cfg.Apply(ret)
+	return nil
+}