package gateway

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"llmsproxy/internal/provider"
)

// TestUI_ChatPageGroupsImageModels is a UI-contract guard for the bug that
// started this: the chat page listed image models beside chat ones, and picking
// one posted to /api/chat, which cannot serve it.
//
// The contract is asserted on the HTML source rather than by running a browser,
// because the failure this must catch is a source-level one — an <option>
// without `disabled`. A DOM assertion in a headless browser would pass right
// up until someone removed the attribute, and then only if a CI machine had the
// whole stack up.
func TestUI_ChatPageGroupsImageModels(t *testing.T) {
	ui := uiSource(t)

	// The dropdown must read model_kinds, not the flat models list. Reading the
	// flat list is what made chat and image models indistinguishable.
	if !strings.Contains(ui, "model_kinds") {
		t.Error("chat page never reads model_kinds; image models will be " +
			"indistinguishable from chat models again")
	}

	// Image options must be rendered disabled. A plain String.replace over the
	// joined HTML only disables the FIRST match — that bug shipped once here
	// (one source disabled, five selectable) — so the assertion looks for the
	// per-item map, not for a global replace.
	if strings.Contains(ui, `imgOpts.join("").replace`) {
		t.Error("chat page disables image options with String.replace over the " +
			"joined HTML, which only rewrites the first option")
	}
	if !strings.Contains(ui, "disabled") {
		t.Error("chat page never emits a disabled attribute for image models")
	}
}

// TestUI_ImageModeIsReachableFromChatTab 钉住生图**仍可达**。
//
// ★ 断言已随 UI 结构调整：生图不再是独立侧栏项，而是对话页里的一个分段模式。
//   原先这条测试钉的是 `data-tab="image"` / `id="tab-image"` / `tab === "image"`
//   —— 三者都已随合并移除。若继续钉旧结构，它只会红着挡住重构，而检不出
//   "生图入口彻底消失"这种真回归。所以改为钉**合并后的可达性**：
//   分段控件在、切换函数在、面板容器在、端点仍在。
//
// 为什么"可达性"才是要守的东西：合并的动机是少一个导航项，而不是把生图功能
// 藏起来。只要用户能从对话页一键切到生图并真的发出请求，这个功能就是完整的。
func TestUI_ImageModeIsReachableFromChatTab(t *testing.T) {
	ui := uiSource(t)

	for _, want := range []string{
		`class="chat-mode-bar"`,      // 分段栏存在
		`switchChatMode('image')`,    // 能切到生图
		`id="ct-image-pane"`,         // 生图面板容器
		`function renderImage`,       // 渲染器还在
		`/v1/images/generations`,     // 真正被调用的端点
	} {
		if !strings.Contains(ui, want) {
			t.Errorf("生图模式不可达，缺少 %q", want)
		}
	}

	// 合并后**不应**再出现独立 tab 的三件套 —— 它们会让 goTab 去找一个不存在的
	// 面板（$("#tab-image") 为 null ⇒ 点侧栏抛错）。
	for _, gone := range []string{
		`data-tab="image"`,
		`id="tab-image"`,
		`tab === "image"`,
	} {
		if strings.Contains(ui, gone) {
			t.Errorf("生图已并入对话页，不应再有独立 tab 结构 %q"+
				"（否则 goTab 会找一个不存在的面板）", gone)
		}
	}

	// 面板必须在 DOM 里且**不能被初始隐藏到底**：切换函数用 display 控制。
	if !strings.Contains(ui, `ct-chat-pane`) {
		t.Error("缺少对话面板容器 ct-chat-pane（切换需要两个容器同时存在）")
	}
}

// TestUI_ImagePageCallsTheImageEndpoint is the discriminator: a page that
// renders an image result but posts to the chat endpoint would produce exactly
// the original failure, just prettier.
func TestUI_ImagePageCallsTheImageEndpoint(t *testing.T) {
	ui := uiSource(t)

	i := strings.Index(ui, "async function sendImage(")
	if i < 0 {
		t.Fatal("sendImage() not found")
	}
	// Bound the search to the function body rather than the whole file, so a
	// /v1/images/generations mention elsewhere cannot satisfy this.
	body := ui[i:]
	if end := strings.Index(body, "\n      function "); end > 0 {
		body = body[:end]
	}
	if end := strings.Index(body, "\n      async function "); end > 0 {
		if s := body[:end]; strings.Contains(s, "/v1/images/generations") {
			body = s
		} else {
			body = body[:end]
		}
	}
	if !strings.Contains(body, "/v1/images/generations") {
		t.Error("sendImage() does not post to /v1/images/generations")
	}
}

// TestSourceStatus_ExposesModelKindsToTheUI is the server half of the same
// contract: the field the UI reads must actually be serialized.
func TestSourceStatus_ExposesModelKindsToTheUI(t *testing.T) {
	st := provider.SourceStatus{
		Name:   "vela",
		Models: []string{"claude-sonnet-5.5", "gpt-image-2"},
		ModelKinds: []provider.ModelKindInfo{
			{ID: "claude-sonnet-5.5", Kind: "chat"},
			{ID: "gpt-image-2", Kind: "image"},
		},
	}
	b, err := json.Marshal(st)
	if err != nil {
		t.Fatal(err)
	}
	var got map[string]interface{}
	if err := json.Unmarshal(b, &got); err != nil {
		t.Fatal(err)
	}
	mk, ok := got["model_kinds"].([]interface{})
	if !ok || len(mk) != 2 {
		t.Fatalf("model_kinds = %v, want 2 entries; the UI cannot split the list without it", got["model_kinds"])
	}
	last := mk[1].(map[string]interface{})
	if last["kind"] != "image" {
		t.Errorf("model_kinds[1].kind = %v, want \"image\"", last["kind"])
	}
}

// TestUI_BaseURLFieldExplainsWhereToCut keeps the second bug fixed: the URL
// hint has to mention the concrete failure, not just say "enter the URL".
func TestUI_BaseURLFieldExplainsWhereToCut(t *testing.T) {
	ui := uiSource(t)
	if !strings.Contains(ui, "urlHint") {
		t.Fatal("no urlHint; the base_url field gives no guidance about /v1")
	}
	hint := ui[strings.Index(ui, "urlHint:"):]
	if len(hint) > 700 {
		hint = hint[:700]
	}
	// The trap is specific and reproducible: base_url ending in /v1 makes chat
	// work and image generation 404. Saying only "enter the URL" reproduces the
	// confusion the hint exists to remove.
	for _, want := range []string{"/v1", "404"} {
		if !strings.Contains(hint, want) {
			t.Errorf("urlHint does not mention %q — the hint must name the concrete failure", want)
		}
	}
}

// TestImageEndpointComposesUnderRealConditions proves the hint describes a
// reachable path rather than a plausible-sounding one.
//
// The case that matters: base_url already ends in /v1 (which is what an
// operator pastes from an SDK example), so the RELATIVE image endpoint composes
// to …/v1/images/generations and works, while the gateway's default ABSOLUTE
// path would produce …/v1/v1/… and 404.
//
// The doubled form is served as a 404 here so the test would fail if the code
// ever reverted to relying on the default.
func TestImageEndpointComposesUnderRealConditions(t *testing.T) {
	up := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		switch r.URL.Path {
		case "/v1/images/generations":
			_, _ = w.Write([]byte(`{"data":[{"url":"http://example.invalid/x.png"}]}`))
		default:
			w.WriteHeader(http.StatusNotFound)
		}
	}))
	defer up.Close()

	// base_url as an operator types it: host root + /v1.
	base := up.URL + "/v1"

	// What discovery writes when base carries a version segment.
	relative := base + "/images/generations"
	resp, err := http.Post(relative, "application/json", strings.NewReader(`{"model":"m"}`))
	if err != nil {
		t.Fatal(err)
	}
	resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		t.Errorf("POST %s = %d, want 200 — the form discovery writes must work", relative, resp.StatusCode)
	}

	// What the gateway's built-in default would produce for the same base_url.
	doubled := base + "/v1/images/generations"
	resp2, err := http.Post(doubled, "application/json", strings.NewReader(`{"model":"m"}`))
	if err != nil {
		t.Fatal(err)
	}
	resp2.Body.Close()
	if resp2.StatusCode != http.StatusNotFound {
		t.Errorf("POST %s = %d, want 404 — this test's premise is that the "+
			"default image path doubles the version segment; if the upstream ever "+
			"accepts it, composeImageEndpoint's rule needs rechecking", doubled, resp2.StatusCode)
	}
}