Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/composite_model_route.go

@@ -0,0 +1,131 @@
+package service
+
+import (
+	"context"
+	"strings"
+	"time"
+
+	infraerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
+)
+
+const (
+	CompositeRouteMatchExact  = "exact"
+	CompositeRouteMatchPrefix = "prefix"
+
+	CompositeRouteEndpointAny             = "any"
+	CompositeRouteEndpointMessages        = "messages"
+	CompositeRouteEndpointCountTokens     = "count_tokens"
+	CompositeRouteEndpointResponses       = "responses"
+	CompositeRouteEndpointChatCompletions = "chat_completions"
+	CompositeRouteEndpointEmbeddings      = "embeddings"
+	CompositeRouteEndpointImages          = "images"
+	CompositeRouteEndpointGemini          = "gemini"
+
+	CompositeRouteSourceExplicit = "route"
+	CompositeRouteSourceDetector = "detector"
+)
+
+var (
+	ErrCompositeRouteNotFound = infraerrors.NotFound("COMPOSITE_ROUTE_NOT_FOUND", "composite route not found")
+	ErrCompositeRouteExists   = infraerrors.Conflict("COMPOSITE_ROUTE_EXISTS", "composite route already exists")
+)
+
+// CompositeModelRoute maps one public model identifier in a composite group to
+// the concrete provider/model that should handle the request.
+type CompositeModelRoute struct {
+	ID             int64     `json:"id"`
+	GroupID        int64     `json:"group_id"`
+	PublicModel    string    `json:"public_model"`
+	MatchType      string    `json:"match_type"`
+	TargetPlatform string    `json:"target_platform"`
+	UpstreamModel  string    `json:"upstream_model"`
+	Endpoint       string    `json:"endpoint"`
+	Priority       int       `json:"priority"`
+	Enabled        bool      `json:"enabled"`
+	Notes          string    `json:"notes"`
+	CreatedAt      time.Time `json:"created_at"`
+	UpdatedAt      time.Time `json:"updated_at"`
+}
+
+type CompositeRoutePreviewRequest struct {
+	Model    string `json:"model"`
+	Endpoint string `json:"endpoint"`
+}
+
+type CompositeRouteDecision struct {
+	Matched        bool                 `json:"matched"`
+	Source         string               `json:"source"`
+	GroupID        int64                `json:"group_id"`
+	PublicModel    string               `json:"public_model"`
+	TargetPlatform string               `json:"target_platform"`
+	UpstreamModel  string               `json:"upstream_model"`
+	Endpoint       string               `json:"endpoint"`
+	Route          *CompositeModelRoute `json:"route,omitempty"`
+	Reason         string               `json:"reason,omitempty"`
+}
+
+type CompositeRouteInput struct {
+	PublicModel    string
+	MatchType      string
+	TargetPlatform string
+	UpstreamModel  string
+	Endpoint       string
+	Priority       int
+	Enabled        bool
+	Notes          string
+}
+
+type CompositeModelRouteRepository interface {
+	ListByGroup(ctx context.Context, groupID int64, includeDisabled bool) ([]CompositeModelRoute, error)
+	Create(ctx context.Context, route *CompositeModelRoute) error
+	Update(ctx context.Context, route *CompositeModelRoute) error
+	Delete(ctx context.Context, id int64) error
+	DeleteByGroup(ctx context.Context, groupID int64) error
+}
+
+func normalizeCompositeRouteEndpoint(endpoint string) string {
+	endpoint = strings.ToLower(strings.TrimSpace(endpoint))
+	if endpoint == "" {
+		return CompositeRouteEndpointAny
+	}
+	switch endpoint {
+	case CompositeRouteEndpointMessages,
+		CompositeRouteEndpointCountTokens,
+		CompositeRouteEndpointResponses,
+		CompositeRouteEndpointChatCompletions,
+		CompositeRouteEndpointEmbeddings,
+		CompositeRouteEndpointImages,
+		CompositeRouteEndpointGemini:
+		return endpoint
+	default:
+		return CompositeRouteEndpointAny
+	}
+}
+
+func normalizeCompositeRouteMatchType(matchType string) string {
+	matchType = strings.ToLower(strings.TrimSpace(matchType))
+	switch matchType {
+	case CompositeRouteMatchPrefix:
+		return CompositeRouteMatchPrefix
+	default:
+		return CompositeRouteMatchExact
+	}
+}
+
+func normalizeCompositeRouteInput(input CompositeRouteInput) CompositeRouteInput {
+	input.PublicModel = strings.TrimSpace(input.PublicModel)
+	input.MatchType = normalizeCompositeRouteMatchType(input.MatchType)
+	input.TargetPlatform = strings.TrimSpace(input.TargetPlatform)
+	input.UpstreamModel = strings.TrimSpace(input.UpstreamModel)
+	input.Endpoint = normalizeCompositeRouteEndpoint(input.Endpoint)
+	// 仅对 exact 路由把空 upstream_model 回填成 public_model：exact 命中时请求模型
+	// 恒等于 public_model，回填只影响持久化/后台展示，保留原有契约不变。
+	// prefix 路由留空则不回填——Resolve 会回退到具体请求模型，从而透传原始模型
+	// （否则 public=deepseek-v4 的前缀路由会把 deepseek-v4-flash / deepseek-v4-pro
+	// 都塌缩成固定的 deepseek-v4）。显式填写 upstream_model 时任何模式都原样固定转发。
+	if input.UpstreamModel == "" && input.MatchType == CompositeRouteMatchExact {
+		input.UpstreamModel = input.PublicModel
+	}
+	input.Notes = strings.TrimSpace(input.Notes)
+	return input
+}