// storage_test.go — /storage/* presigned 代理 handler 的 unit test。
//
// Owner: testing agent（補測任務 — internal/api 弱處 handler）
//
// 測試對象：storage.go 的 storageGetHandler / storagePutHandler / verifyStorageSignature /
// storageKeyFromPath / registerStorageRoutes。
//
// 策略：用真 *storage.LocalFSStore（t.TempDir() 後端、unit 性質、不需 docker）+ httptest 打 handler。
// 簽章用 store 的 PresignedGetURL / PresignedPutURL 產生（與生產同一條簽章邏輯），
// 再從產出的 URL 拆出 expires / signature 組請求 — 避免測試自己重刻 HMAC（會脆弱）。
package api

import (
	"bytes"
	"context"
	"io"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"visiona-backend/internal/storage"
)

func init() {
	gin.SetMode(gin.TestMode)
}

// newStorageTestServer 建立一個只掛 /storage/* 路由的 gin engine（HMAC 控管、不經 AuthMiddleware）。
func newStorageTestServer(t *testing.T, deps Deps) *gin.Engine {
	t.Helper()
	r := gin.New()
	registerStorageRoutes(r, deps)
	return r
}

// newLocalStore 建立一個 t.TempDir() 後端、固定 secret 的 LocalFSStore。
func newLocalStore(t *testing.T) *storage.LocalFSStore {
	t.Helper()
	s, err := storage.NewLocalFSStore(t.TempDir(), "http://localhost:3721/storage", "storage-test-secret")
	require.NoError(t, err)
	return s
}

// signedQuery 用 store 的 presigned 邏輯產生 method 對應的 (expires, signature) query 字串。
// 回傳形如 "expires=...&signature=..." 的 raw query（不含前導 ?）。
func signedQuery(t *testing.T, s *storage.LocalFSStore, method, key string, ttl time.Duration) string {
	t.Helper()
	var raw string
	var err error
	switch method {
	case http.MethodGet:
		raw, err = s.PresignedGetURL(context.Background(), key, ttl)
	case http.MethodPut:
		raw, err = s.PresignedPutURL(context.Background(), key, ttl)
	default:
		t.Fatalf("unsupported method %q", method)
	}
	require.NoError(t, err)
	u, err := url.Parse(raw)
	require.NoError(t, err)
	q := u.Query()
	// 只保留 expires / signature（mode 不影響 handler 驗簽）。
	out := url.Values{}
	out.Set("expires", q.Get("expires"))
	out.Set("signature", q.Get("signature"))
	return out.Encode()
}

// ───────────────────────── storageKeyFromPath（純函式）─────────────────────────

func TestStorageKeyFromPath(t *testing.T) {
	t.Parallel()
	cases := []struct {
		name string
		in   string
		want string
	}{
		{"happy: 去掉前導斜線", "/models/u1/a.nef", "models/u1/a.nef"},
		{"empty: 空字串", "", ""},
		{"boundary: 只有一個斜線", "/", ""},
		{"無前導斜線時原樣回傳", "models/a.nef", "models/a.nef"},
		{"巢狀深路徑", "/a/b/c/d.bin", "a/b/c/d.bin"},
	}
	for _, tc := range cases {
		tc := tc
		t.Run(tc.name, func(t *testing.T) {
			t.Parallel()
			assert.Equal(t, tc.want, storageKeyFromPath(tc.in))
		})
	}
}

// ───────────────────────── registerStorageRoutes ─────────────────────────

// Storage 為 nil 時不註冊任何 /storage/* 路由（handler 不存在 → gin 回 404）。
func TestRegisterStorageRoutes_NilStorage_NoRoutes(t *testing.T) {
	t.Parallel()
	r := newStorageTestServer(t, Deps{Storage: nil})

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/storage/models/x.nef?expires=1&signature=abc", nil)
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusNotFound, w.Code,
		"Storage 為 nil 時不應註冊路由，gin 對未知路由回 404")
}

// ───────────────────────── PUT happy + GET happy（round-trip）─────────────────────────

// 完整 round-trip：簽章 PUT 寫入 → 簽章 GET 讀回，內容一致。
func TestStoragePut_Then_Get_RoundTrip(t *testing.T) {
	s := newLocalStore(t)
	r := newStorageTestServer(t, Deps{Storage: s})
	key := "models/user-1/round.nef"
	payload := []byte("visiona-round-trip-bytes")

	// PUT
	putW := httptest.NewRecorder()
	putReq := httptest.NewRequest(http.MethodPut,
		"/storage/"+key+"?"+signedQuery(t, s, http.MethodPut, key, time.Hour),
		bytes.NewReader(payload))
	putReq.ContentLength = int64(len(payload))
	r.ServeHTTP(putW, putReq)
	require.Equal(t, http.StatusNoContent, putW.Code, "簽章正確的 PUT 應回 204")

	// 底層 storage 確實有寫入
	gotObj, _, err := s.Get(context.Background(), key)
	require.NoError(t, err)
	_ = gotObj.Close()

	// GET
	getW := httptest.NewRecorder()
	getReq := httptest.NewRequest(http.MethodGet,
		"/storage/"+key+"?"+signedQuery(t, s, http.MethodGet, key, time.Hour), nil)
	r.ServeHTTP(getW, getReq)

	require.Equal(t, http.StatusOK, getW.Code, "簽章正確的 GET 應回 200")
	assert.Equal(t, payload, getW.Body.Bytes(), "GET 內容應與 PUT 寫入一致")
	assert.Equal(t, "application/octet-stream", getW.Header().Get("Content-Type"))
	assert.Equal(t, "24", getW.Header().Get("Content-Length"))
}

// ───────────────────────── GET 錯誤路徑 ─────────────────────────

// GET 缺 signature/expires → 403 INVALID_SIGNATURE。
func TestStorageGet_MissingSignature_403(t *testing.T) {
	s := newLocalStore(t)
	r := newStorageTestServer(t, Deps{Storage: s})

	w := httptest.NewRecorder()
	// 沒有任何 query 參數
	req := httptest.NewRequest(http.MethodGet, "/storage/models/u1/a.nef", nil)
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusForbidden, w.Code)
	assert.Contains(t, w.Body.String(), ErrCodeInvalidSignature)
}

// GET 簽章被竄改 → 403。
func TestStorageGet_TamperedSignature_403(t *testing.T) {
	s := newLocalStore(t)
	r := newStorageTestServer(t, Deps{Storage: s})
	key := "models/u1/a.nef"

	q := signedQuery(t, s, http.MethodGet, key, time.Hour)
	tampered := strings.Replace(q, "signature=", "signature=ZZZ", 1)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/storage/"+key+"?"+tampered, nil)
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusForbidden, w.Code)
	assert.Contains(t, w.Body.String(), ErrCodeInvalidSignature)
}

// GET 簽章已過期（boundary：負 ttl → expires 在過去）→ 403。
func TestStorageGet_ExpiredSignature_403(t *testing.T) {
	s := newLocalStore(t)
	r := newStorageTestServer(t, Deps{Storage: s})
	key := "models/u1/a.nef"

	// ttl 為負 → presignedURL 產出的 expires 在過去 → VerifySignature 走過期分支
	q := signedQuery(t, s, http.MethodGet, key, -time.Hour)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/storage/"+key+"?"+q, nil)
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusForbidden, w.Code)
	assert.Contains(t, w.Body.String(), ErrCodeInvalidSignature)
}

// GET 簽章正確但 object 不存在 → 404 NOT_FOUND。
func TestStorageGet_NotFound_404(t *testing.T) {
	s := newLocalStore(t)
	r := newStorageTestServer(t, Deps{Storage: s})
	key := "models/u1/missing.nef" // 從未 Put 過

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/storage/"+key+"?"+signedQuery(t, s, http.MethodGet, key, time.Hour), nil)
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusNotFound, w.Code)
	assert.Contains(t, w.Body.String(), ErrCodeNotFound)
}

// expires 非數字 → verifyStorageSignature 在 ParseInt 失敗 → 403。
func TestStorageGet_NonNumericExpires_403(t *testing.T) {
	s := newLocalStore(t)
	r := newStorageTestServer(t, Deps{Storage: s})

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/storage/models/u1/a.nef?expires=not-a-number&signature=abc", nil)
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusForbidden, w.Code)
	assert.Contains(t, w.Body.String(), ErrCodeInvalidSignature)
}

// ───────────────────────── PUT 錯誤路徑 ─────────────────────────

// PUT 缺簽章 → 403，且不應寫入底層 storage。
func TestStoragePut_MissingSignature_403_NoWrite(t *testing.T) {
	s := newLocalStore(t)
	r := newStorageTestServer(t, Deps{Storage: s})
	key := "models/u1/nowrite.nef"

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodPut, "/storage/"+key,
		bytes.NewReader([]byte("should-not-persist")))
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusForbidden, w.Code)
	assert.Contains(t, w.Body.String(), ErrCodeInvalidSignature)

	// 驗簽失敗 → 不應寫入
	_, _, err := s.Get(context.Background(), key)
	assert.ErrorIs(t, err, storage.ErrNotFound, "驗簽失敗的 PUT 不應寫入 storage")
}

// PUT 用 GET 方法的簽章（method mismatch）→ 403（簽章把 method 綁進 payload）。
func TestStoragePut_WrongMethodSignature_403(t *testing.T) {
	s := newLocalStore(t)
	r := newStorageTestServer(t, Deps{Storage: s})
	key := "models/u1/methodmix.nef"

	// 用 GET 簽章去打 PUT
	q := signedQuery(t, s, http.MethodGet, key, time.Hour)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodPut, "/storage/"+key+"?"+q,
		bytes.NewReader([]byte("x")))
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusForbidden, w.Code,
		"GET 簽章不能用於 PUT（method 綁進簽章 payload）")
}

// ───────────────────────── verifyStorageSignature: 非 LocalFS backend ─────────────────────────

// fakeNonLocalStore 是一個非 *LocalFSStore 的 storage.Store 實作，
// 用來驗 verifyStorageSignature 對「非 LocalFS backend」直接回 ErrInvalidSignature。
type fakeNonLocalStore struct{}

func (fakeNonLocalStore) Put(ctx context.Context, key string, r io.Reader, size int64, meta map[string]string) error {
	return nil
}
func (fakeNonLocalStore) Get(ctx context.Context, key string) (io.ReadCloser, *storage.Object, error) {
	return nil, nil, storage.ErrNotFound
}
func (fakeNonLocalStore) Stat(ctx context.Context, key string) (*storage.Object, error) {
	return nil, storage.ErrNotFound
}
func (fakeNonLocalStore) Exists(ctx context.Context, key string) (bool, error) { return false, nil }
func (fakeNonLocalStore) Delete(ctx context.Context, key string) error         { return nil }
func (fakeNonLocalStore) List(ctx context.Context, prefix string) ([]*storage.Object, error) {
	return nil, nil
}
func (fakeNonLocalStore) PresignedGetURL(ctx context.Context, key string, ttl time.Duration) (string, error) {
	return "", nil
}
func (fakeNonLocalStore) PresignedPutURL(ctx context.Context, key string, ttl time.Duration) (string, error) {
	return "", nil
}

// 非 LocalFS backend：即使帶 query，verifyStorageSignature type-assert 失敗 → 403。
func TestStorageGet_NonLocalFSBackend_403(t *testing.T) {
	r := newStorageTestServer(t, Deps{Storage: fakeNonLocalStore{}})

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/storage/models/u1/a.nef?expires=99999999999&signature=whatever", nil)
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusForbidden, w.Code,
		"非 *LocalFSStore backend 不應通過 /storage 驗簽")
	assert.Contains(t, w.Body.String(), ErrCodeInvalidSignature)
}