package server

import (
	"context"
	"testing"

	"perms-system-server/internal/svc"
	"perms-system-server/internal/testutil"
	"perms-system-server/pb"

	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

// TC-0794: gRPC VerifyToken 契约层 fuzz —— 任意畸形 AccessToken 必须:
// (1) 返回 (resp, nil) 而非 panic / (nil, err), 因为签名/过期/payload 问题在对外契约里都只是"无效令牌"
// (2) 当返回时 resp.Valid 必须为 false (不能误把 nil token 判成有效)
//
// 种子覆盖常见的攻击 payload: 空串、非 JWT 结构、alg=none 试探、超长串、Unicode 噪声、控制字符。
// 在 CI 里 `go test -run ^FuzzVerifyToken$` 只会执行种子语料, 不会触发随机变异, 因此确定性高、耗时可控。
// 本地做 `go test -fuzz=FuzzVerifyToken -fuzztime=30s` 可进一步跑随机变异。
func FuzzVerifyToken_NeverPanicsAlwaysInvalid(f *testing.F) {
	svcCtx := svc.NewServiceContext(testutil.GetTestConfig())
	srv := NewPermServer(svcCtx)

	seeds := []string{
		"",
		" ",
		".",
		"..",
		"not.a.jwt",
		"a.b.c",
		"eyJhbGciOiJub25lIn0.eyJ1c2VySWQiOjF9.", // alg=none 试探
		"Bearer xxx",
		"null",
		"\x00\x01\x02",
		"🔥token💥",
		string(make([]byte, 4096)), // 长令牌
		"eyJhbGciOiJIUzI1NiJ9.eyJleHAiOjF9.sig", // 伪造 HS256
	}
	for _, s := range seeds {
		f.Add(s)
	}

	f.Fuzz(func(t *testing.T, raw string) {
		defer func() {
			if r := recover(); r != nil {
				t.Fatalf("VerifyToken panicked on input=%q: %v", raw, r)
			}
		}()
		resp, err := srv.VerifyToken(context.Background(), &pb.VerifyTokenReq{AccessToken: raw})
		if err != nil {
			t.Fatalf("VerifyToken must never return an error for malformed input, got err=%v (input=%q)", err, raw)
		}
		if resp == nil {
			t.Fatalf("VerifyToken must return non-nil response (input=%q)", raw)
		}
		if resp.Valid {
			t.Fatalf("malformed/invalid token must never be reported valid; input=%q", raw)
		}
	})
}

// TC-0795: gRPC GetUserPerms 契约层 fuzz —— 任意 (appKey, appSecret, productCode, userId) 组合下:
// (1) 必须返回 status.Error(非 200); 不允许 panic / nil error + 有权限返回
// (2) 错误码必须落在固定集合内: Unauthenticated / PermissionDenied / InvalidArgument / NotFound / Internal
//     —— 否则契约漂移, 产品侧"权限网关"无法稳定处理
//
// 此用例不需要预置任何数据, 专打输入校验/认证失败的快速拒绝路径。
func FuzzGetUserPerms_ErrorTaxonomyStable(f *testing.F) {
	svcCtx := svc.NewServiceContext(testutil.GetTestConfig())
	srv := NewPermServer(svcCtx)

	seeds := [][4]string{
		{"", "", "", ""},
		{"nonexistent_appkey_" + testutil.UniqueId(), "x", "p", "1"},
		{"appkey", "wrong_secret", "code", "0"},
		{"🔑", "🔒", "😈", "-1"},
		{"'; DROP TABLE sys_product; --", "s", "p", "1"},
		{string(make([]byte, 512)), "s", "p", "1"},
	}
	for _, s := range seeds {
		f.Add(s[0], s[1], s[2], s[3])
	}

	allowed := map[codes.Code]bool{
		codes.Unauthenticated:  true,
		codes.PermissionDenied: true,
		codes.InvalidArgument:  true,
		codes.NotFound:         true,
		codes.Internal:         true,
	}

	f.Fuzz(func(t *testing.T, appKey, appSecret, productCode, userIdStr string) {
		defer func() {
			if r := recover(); r != nil {
				t.Fatalf("GetUserPerms panicked on input=(%q,%q,%q,%q): %v", appKey, appSecret, productCode, userIdStr, r)
			}
		}()
		var uid int64
		for _, c := range userIdStr {
			if c >= '0' && c <= '9' {
				uid = uid*10 + int64(c-'0')
				if uid > 1e15 {
					break
				}
			}
		}
		_, err := srv.GetUserPerms(context.Background(), &pb.GetUserPermsReq{
			AppKey: appKey, AppSecret: appSecret, ProductCode: productCode, UserId: uid,
		})
		if err == nil {
			t.Fatalf("malformed/unauthenticated input must produce an error; appKey=%q", appKey)
		}
		st, ok := status.FromError(err)
		if !ok {
			t.Fatalf("error must be a grpc status.Error, got %T (%v)", err, err)
		}
		if !allowed[st.Code()] {
			t.Fatalf("error code %s is outside the agreed contract taxonomy; must be one of Unauthenticated/PermissionDenied/InvalidArgument/NotFound/Internal. msg=%q",
				st.Code(), st.Message())
		}
	})
}