// client_test.go 用 httptest 伺服器驗證用戶端行為：分頁（limit=50）、
// 認證表頭、逾時與錯誤映射（連線失敗、401、5xx → *ErrAPI）。
package gitea

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"net/http/httptest"
	"sync/atomic"
	"testing"
	"time"
)

// newTestClient 對 srv 建立用戶端。
func newTestClient(srvURL, token string, timeout time.Duration) (*Client, error) {
	return New(srvURL, token, timeout)
}

func TestNewRejectsInvalidBaseURL(t *testing.T) {
	for _, bad := range []string{"", "not a url", "http://"} {
		if _, err := New(bad, "", 0); err == nil {
			t.Errorf("New(%q) should fail", bad)
		}
	}
}

func TestClientSendsTokenHeader(t *testing.T) {
	var gotAuth atomic.Value
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotAuth.Store(r.Header.Get("Authorization"))
		fmt.Fprint(w, `{"login":"max"}`)
	}))
	defer srv.Close()

	c, err := newTestClient(srv.URL, "secret-token", time.Second)
	if err != nil {
		t.Fatal(err)
	}
	var out map[string]any
	if err := c.GetJSON(context.Background(), "/user", &out); err != nil {
		t.Fatal(err)
	}
	if got := gotAuth.Load(); got != "token secret-token" {
		t.Fatalf("Authorization header = %v, want token secret-token", got)
	}
}

func TestErrAPIMessageHasNoToken(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusUnauthorized)
	}))
	defer srv.Close()

	c, err := newTestClient(srv.URL, "secret-token", time.Second)
	if err != nil {
		t.Fatal(err)
	}
	err = c.GetJSON(context.Background(), "/user", nil)
	var apiErr *ErrAPI
	if !errors.As(err, &apiErr) {
		t.Fatalf("want *ErrAPI, got %v", err)
	}
	if apiErr.StatusCode != http.StatusUnauthorized {
		t.Fatalf("status = %d, want 401", apiErr.StatusCode)
	}
	if got := apiErr.Error(); got == "" || contains(got, "secret-token") {
		t.Fatalf("error message must not leak token, got %q", got)
	}
}

func TestListAllPaginatesWithLimitFifty(t *testing.T) {
	var calls int32
	var limits []int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		atomic.AddInt32(&calls, 1)
		limit := int32(0)
		fmt.Sscanf(r.URL.Query().Get("limit"), "%d", &limit)
		limits = append(limits, limit)
		page := 1
		fmt.Sscanf(r.URL.Query().Get("page"), "%d", &page)
		// 第 1、2 頁各滿 50 筆，第 3 頁 10 筆後結束。
		total := 110
		start := (page - 1) * 50
		end := start + 50
		if end > total {
			end = total
		}
		w.Header().Set("Content-Type", "application/json")
		if start >= total {
			fmt.Fprint(w, "[]")
			return
		}
		items := make([]int, 0, end-start)
		for i := start; i < end; i++ {
			items = append(items, i)
		}
		_ = json.NewEncoder(w).Encode(items)
	}))
	defer srv.Close()

	c, err := newTestClient(srv.URL, "", time.Second)
	if err != nil {
		t.Fatal(err)
	}
	var got []int
	if err := c.ListAll(context.Background(), "/things", ListOptions{}, &got); err != nil {
		t.Fatal(err)
	}
	if len(got) != 110 {
		t.Fatalf("want 110 items, got %d", len(got))
	}
	for i, v := range got {
		if v != i {
			t.Fatalf("item %d = %d, want %d", i, v, i)
		}
	}
	if n := atomic.LoadInt32(&calls); n != 3 {
		t.Fatalf("want 3 page requests, got %d", n)
	}
	for i, l := range limits {
		if l != 50 {
			t.Fatalf("page %d limit = %d, want 50", i+1, l)
		}
	}
}

func TestListAllRejectsBadOut(t *testing.T) {
	c, err := newTestClient("https://gitea.alterminal.com", "", time.Second)
	if err != nil {
		t.Fatal(err)
	}
	var notSlice int
	if err := c.ListAll(context.Background(), "/x", ListOptions{}, &notSlice); err == nil {
		t.Fatal("non-slice out should error")
	}
	preloaded := []int{1}
	if err := c.ListAll(context.Background(), "/x", ListOptions{}, &preloaded); err == nil {
		t.Fatal("non-empty out should error")
	}
}

func TestClientTimeoutSurfacesAsErrAPI(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		time.Sleep(200 * time.Millisecond)
		fmt.Fprint(w, `{}`)
	}))
	defer srv.Close()

	c, err := newTestClient(srv.URL, "", 50*time.Millisecond)
	if err != nil {
		t.Fatal(err)
	}
	err = c.GetJSON(context.Background(), "/user", nil)
	var apiErr *ErrAPI
	if !errors.As(err, &apiErr) {
		t.Fatalf("timeout should surface as *ErrAPI, got %v", err)
	}
	if apiErr.StatusCode != 0 {
		t.Fatalf(" StatusCode should be 0 for transport error, got %d", apiErr.StatusCode)
	}
}

func TestClientServerFiveHundred(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusInternalServerError)
	}))
	defer srv.Close()

	c, err := newTestClient(srv.URL, "", time.Second)
	if err != nil {
		t.Fatal(err)
	}
	err = c.GetJSON(context.Background(), "/user", nil)
	var apiErr *ErrAPI
	if !errors.As(err, &apiErr) || apiErr.StatusCode != 500 {
		t.Fatalf("want *ErrAPI with 500, got %v", err)
	}
}

// contains 是簡單子字串檢查（避免只為此引入 strings 到測試以外的地方）。
func contains(s, sub string) bool {
	return len(s) >= len(sub) && (s == sub || len(sub) == 0 || indexOf(s, sub) >= 0)
}

func indexOf(s, sub string) int {
	for i := 0; i+len(sub) <= len(s); i++ {
		if s[i:i+len(sub)] == sub {
			return i
		}
	}
	return -1
}