feat: add claude max usage simulation with group switch

backend/internal/service/claude_max_simulation_test.go

@@ -0,0 +1,92 @@
+package service
+
+import "testing"
+
+func TestProjectUsageToClaudeMax1H_Conservation(t *testing.T) {
+	usage := &ClaudeUsage{
+		InputTokens:              1200,
+		CacheCreationInputTokens: 0,
+		CacheCreation5mTokens:    0,
+		CacheCreation1hTokens:    0,
+	}
+	parsed := &ParsedRequest{
+		Model: "claude-sonnet-4-5",
+		Messages: []any{
+			map[string]any{
+				"role":    "user",
+				"content": "请帮我总结这段代码并给出优化建议",
+			},
+		},
+	}
+
+	changed := projectUsageToClaudeMax1H(usage, parsed)
+	if !changed {
+		t.Fatalf("expected usage to be projected")
+	}
+
+	total := usage.InputTokens + usage.CacheCreation5mTokens + usage.CacheCreation1hTokens
+	if total != 1200 {
+		t.Fatalf("total tokens changed: got=%d want=%d", total, 1200)
+	}
+	if usage.CacheCreation5mTokens != 0 {
+		t.Fatalf("cache_creation_5m should be 0, got=%d", usage.CacheCreation5mTokens)
+	}
+	if usage.InputTokens <= 0 || usage.InputTokens >= 1200 {
+		t.Fatalf("simulated input out of range, got=%d", usage.InputTokens)
+	}
+	if usage.CacheCreation1hTokens <= 0 {
+		t.Fatalf("cache_creation_1h should be > 0, got=%d", usage.CacheCreation1hTokens)
+	}
+	if usage.CacheCreationInputTokens != usage.CacheCreation1hTokens {
+		t.Fatalf("cache_creation_input_tokens mismatch: got=%d want=%d", usage.CacheCreationInputTokens, usage.CacheCreation1hTokens)
+	}
+}
+
+func TestComputeClaudeMaxSimulatedInputTokens_Deterministic(t *testing.T) {
+	parsed := &ParsedRequest{
+		Model: "claude-opus-4-5",
+		Messages: []any{
+			map[string]any{
+				"role": "user",
+				"content": []any{
+					map[string]any{"type": "text", "text": "请整理以下日志并定位错误根因"},
+					map[string]any{"type": "tool_use", "name": "grep_logs"},
+				},
+			},
+		},
+	}
+
+	got1 := computeClaudeMaxSimulatedInputTokens(4096, parsed)
+	got2 := computeClaudeMaxSimulatedInputTokens(4096, parsed)
+	if got1 != got2 {
+		t.Fatalf("non-deterministic input tokens: %d != %d", got1, got2)
+	}
+}
+
+func TestShouldSimulateClaudeMaxUsage(t *testing.T) {
+	group := &Group{
+		Platform:                 PlatformAnthropic,
+		SimulateClaudeMaxEnabled: true,
+	}
+	input := &RecordUsageInput{
+		Result: &ForwardResult{
+			Model: "claude-sonnet-4-5",
+			Usage: ClaudeUsage{
+				InputTokens:              3000,
+				CacheCreationInputTokens: 0,
+				CacheCreation5mTokens:    0,
+				CacheCreation1hTokens:    0,
+			},
+		},
+		APIKey: &APIKey{Group: group},
+	}
+
+	if !shouldSimulateClaudeMaxUsage(input) {
+		t.Fatalf("expected simulate=true for claude group without cache creation")
+	}
+
+	input.Result.Usage.CacheCreationInputTokens = 100
+	if shouldSimulateClaudeMaxUsage(input) {
+		t.Fatalf("expected simulate=false when cache creation already exists")
+	}
+}