package gateway

import (
	"net/http"
	"testing"
)

// 客户端自带的会话标识必须被采纳：它比「首条 user 消息指纹」更准
// （历史压缩后指纹会漂移），也是唯一能天然按会话隔离的来源。
func TestClientSessionFromRequestHeaders(t *testing.T) {
	cases := []struct {
		name    string
		headers map[string]string
		bodyKey string
		want    string
	}{
		{"pi 默认格式 x-session-affinity", map[string]string{"X-Session-Affinity": "ses-1"}, "", "ses-1"},
		{"openrouter 格式 x-session-id", map[string]string{"X-Session-Id": "ses-2"}, "", "ses-2"},
		{"openai 格式 session_id", map[string]string{"Session-Id": "ses-3"}, "", "ses-3"},
		{"body prompt_cache_key 兜底", nil, "cache-4", "cache-4"},
		{"头优先于 body", map[string]string{"X-Session-Affinity": "ses-5"}, "cache-x", "ses-5"},
		{"空白不算", map[string]string{"X-Session-Affinity": "   "}, "", ""},
		{"都没有则为空（适配器自行推导）", nil, "", ""},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			r, _ := http.NewRequest(http.MethodPost, "/v1/chat/completions", nil)
			for k, v := range tc.headers {
				r.Header.Set(k, v)
			}
			if got := clientSessionFromRequest(r, tc.bodyKey); got != tc.want {
				t.Errorf("clientSessionFromRequest = %q, want %q", got, tc.want)
			}
		})
	}
}

// 刻意不采纳 x-client-request-id：名字含 request，部分客户端每请求都换，
// 拿它当会话会让上游前缀缓存永不命中。
func TestClientRequestIDIsNotUsedAsSession(t *testing.T) {
	r, _ := http.NewRequest(http.MethodPost, "/v1/chat/completions", nil)
	r.Header.Set("X-Client-Request-Id", "per-request-uuid")
	if got := clientSessionFromRequest(r, ""); got != "" {
		t.Errorf("x-client-request-id 不应被当作会话（否则缓存永不命中），got %q", got)
	}
}