refactor: refactor relay part (#957)

* refactor: refactor relay part

* refactor: refactor config part

relay/constant/relay_mode.go

@@ -0,0 +1,42 @@
+package constant
+
+import "strings"
+
+const (
+	RelayModeUnknown = iota
+	RelayModeChatCompletions
+	RelayModeCompletions
+	RelayModeEmbeddings
+	RelayModeModerations
+	RelayModeImagesGenerations
+	RelayModeEdits
+	RelayModeAudioSpeech
+	RelayModeAudioTranscription
+	RelayModeAudioTranslation
+)
+
+func Path2RelayMode(path string) int {
+	relayMode := RelayModeUnknown
+	if strings.HasPrefix(path, "/v1/chat/completions") {
+		relayMode = RelayModeChatCompletions
+	} else if strings.HasPrefix(path, "/v1/completions") {
+		relayMode = RelayModeCompletions
+	} else if strings.HasPrefix(path, "/v1/embeddings") {
+		relayMode = RelayModeEmbeddings
+	} else if strings.HasSuffix(path, "embeddings") {
+		relayMode = RelayModeEmbeddings
+	} else if strings.HasPrefix(path, "/v1/moderations") {
+		relayMode = RelayModeModerations
+	} else if strings.HasPrefix(path, "/v1/images/generations") {
+		relayMode = RelayModeImagesGenerations
+	} else if strings.HasPrefix(path, "/v1/edits") {
+		relayMode = RelayModeEdits
+	} else if strings.HasPrefix(path, "/v1/audio/speech") {
+		relayMode = RelayModeAudioSpeech
+	} else if strings.HasPrefix(path, "/v1/audio/transcriptions") {
+		relayMode = RelayModeAudioTranscription
+	} else if strings.HasPrefix(path, "/v1/audio/translations") {
+		relayMode = RelayModeAudioTranslation
+	}
+	return relayMode
+}