package web

import (
	"context"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"gitea.mynodes.xyz/ilker/llmgw/internal/control/adminapi"
	"gitea.mynodes.xyz/ilker/llmgw/internal/store"
)

func get(t *testing.T, h http.Handler, target string, headers map[string]string) (int, string) {
	t.Helper()
	r := httptest.NewRequest(http.MethodGet, target, nil)
	for k, v := range headers {
		r.Header.Set(k, v)
	}
	w := httptest.NewRecorder()
	h.ServeHTTP(w, r)
	return w.Code, w.Body.String()
}

func TestLandingPageTellsYouHowToConnect(t *testing.T) {
	code, body := get(t, Landing("v1.2.3", true), "http://llmgw.example/", nil)
	if code != http.StatusOK {
		t.Fatalf("status %d", code)
	}
	for _, want := range []string{"http://llmgw.example/v1", "Authorization: Bearer", "v1.2.3"} {
		if !strings.Contains(body, want) {
			t.Errorf("the page does not mention %q", want)
		}
	}
}

func TestLandingPageSaysNothingAboutWhatIsHere(t *testing.T) {
	// It is served without a key, to anyone who can reach the address. Anything
	// on it is public, so nothing about the cluster belongs on it.
	_, body := get(t, Landing("v1", true), "http://llmgw.example/", nil)
	for _, leak := range []string{"llama", "qwen", "10.0.0.", "replica", "node01"} {
		if strings.Contains(strings.ToLower(body), leak) {
			t.Errorf("the landing page leaks %q", leak)
		}
	}
}

func TestLandingPageWarnsWhenTheGatewayIsOpen(t *testing.T) {
	// Someone who reaches this page on an unauthenticated gateway should learn
	// that from the page rather than by discovering they can use it.
	_, open := get(t, Landing("v1", false), "http://llmgw.example/", nil)
	if !strings.Contains(open, "no API keys configured") {
		t.Error("an open gateway does not say so")
	}
	_, closed := get(t, Landing("v1", true), "http://llmgw.example/", nil)
	if strings.Contains(closed, "no API keys configured") {
		t.Error("a closed gateway claims to be open")
	}
}

func TestTheExampleURLSurvivesAReverseProxy(t *testing.T) {
	// The process sees http and an internal host; the client used https and a
	// public name. An example naming the internal address is one nobody can
	// paste anywhere.
	_, body := get(t, Landing("v1", true), "http://10.0.0.140:8080/", map[string]string{
		"X-Forwarded-Proto": "https",
		"X-Forwarded-Host":  "llmgw.mynodes.xyz",
	})
	if !strings.Contains(body, "https://llmgw.mynodes.xyz/v1") {
		t.Error("the example does not use the address the client actually used")
	}
	if strings.Contains(body, "10.0.0.140") {
		t.Error("the internal address leaked into the page")
	}
}

func TestForwardedHeaderChainsTakeTheFirstEntry(t *testing.T) {
	// A chain of proxies appends rather than replaces.
	_, body := get(t, Landing("v1", true), "http://internal/", map[string]string{
		"X-Forwarded-Proto": "https, http",
		"X-Forwarded-Host":  "llmgw.example, internal",
	})
	if !strings.Contains(body, "https://llmgw.example/v1") {
		t.Errorf("the base URL was built from the wrong entry")
	}
}

func TestOnlyTheRootIsTheLandingPage(t *testing.T) {
	// A catch-all would turn every mistyped path into this page, hiding real
	// 404s from anyone debugging a client.
	code, _ := get(t, Landing("v1", true), "http://x/v1/chat/completionz", nil)
	if code != http.StatusNotFound {
		t.Errorf("a mistyped path returned %d", code)
	}
}

// fakeSource is a cluster for the dashboard to render.
type fakeSource struct{}

func (fakeSource) Nodes() []adminapi.NodeView {
	return []adminapi.NodeView{{
		ID: "llmgw-node01", State: "ready", GPUTotal: 8, GPUFree: 4,
		Classes: []string{"h100-80g"}, Fabrics: []string{"ib-a"},
		Replicas: 1, LastSeenAgo: "2s", AgentVersion: "v0.5.0",
		Unhealthy: []string{"gpu 3: ECC errors"},
	}}
}

func (fakeSource) Models() []adminapi.ModelView {
	return []adminapi.ModelView{
		{Name: "served", Ready: 1, Min: 1, Max: 2, Profiles: []string{"tp4"}},
		{Name: "stuck", Ready: 0, Min: 1, Max: 1, Profiles: []string{"tp8"}},
	}
}

func (fakeSource) Replicas(string) []adminapi.ReplicaView {
	return []adminapi.ReplicaView{{
		ID: "served-1", Model: "served", State: "ready", Pool: "ib-a/h100-80g",
		Endpoint: "http://10.0.0.141:20000", AgeSec: 3600,
		Shards: []adminapi.ShardView{{ID: "served-1-r0", Node: "llmgw-node01"}},
	}}
}

func (fakeSource) Explain(model string) adminapi.ExplainView {
	if model != "stuck" {
		return adminapi.ExplainView{Model: model, Placed: true}
	}
	return adminapi.ExplainView{Model: "stuck", Rejections: []adminapi.RejectionView{
		{Profile: "tp8", Node: "llmgw-node01", Reason: "has 4 free h100-80g GPUs, needs 8"},
	}}
}

type fakeUsage struct{ err error }

func (f fakeUsage) UsageSince(context.Context, time.Time) ([]store.KeyUsage, error) {
	if f.err != nil {
		return nil, f.err
	}
	return []store.KeyUsage{{
		KeyID: "key-1", KeyName: "laptop", KeyPrefix: "sk-llmgw-ab12…",
		ProjectID: "chat", Requests: 42, Errors: 2,
		Prompt: 1000, Completion: 3000, CostMicros: 4_500_000,
		LastAt: time.Now().Add(-time.Minute),
	}}, nil
}

func TestDashboardShowsTheCluster(t *testing.T) {
	h := Dashboard(fakeSource{}, fakeUsage{}, "v1", time.Second, nil)
	code, body := get(t, h, "http://127.0.0.1:9090/", nil)
	if code != http.StatusOK {
		t.Fatalf("status %d", code)
	}
	for _, want := range []string{
		"llmgw-node01", "h100-80g", "served-1", "http://10.0.0.141:20000",
		"ECC errors", "laptop", "4.50", // spend shown in units, not micro-units
	} {
		if !strings.Contains(body, want) {
			t.Errorf("the dashboard does not show %q", want)
		}
	}
}

func TestDashboardExplainsOnlyWhatIsUnplaced(t *testing.T) {
	// Asking why a satisfied model was not placed gives an empty answer, and a
	// page full of empty answers hides the one that matters.
	h := Dashboard(fakeSource{}, nil, "v1", time.Second, nil)
	_, body := get(t, h, "http://127.0.0.1:9090/", nil)

	if !strings.Contains(body, "needs 8") {
		t.Error("the unplaced model has no explanation")
	}
	if strings.Count(body, "Why nothing was placed") != 1 {
		t.Error("the explanation section is missing or duplicated")
	}
}

func TestDashboardSurvivesAFailingUsageQuery(t *testing.T) {
	// A reporting query failing must not take the page with it: the cluster
	// state is what someone is most likely here for.
	h := Dashboard(fakeSource{}, fakeUsage{err: context.DeadlineExceeded}, "v1", time.Second, nil)
	code, body := get(t, h, "http://127.0.0.1:9090/", nil)
	if code != http.StatusOK {
		t.Fatalf("status %d", code)
	}
	if !strings.Contains(body, "llmgw-node01") {
		t.Error("the cluster state was lost with the usage query")
	}
}

func TestDashboardSaysWhenThereIsNothingToAccount(t *testing.T) {
	h := Dashboard(fakeSource{}, nil, "v1", time.Second, nil)
	_, body := get(t, h, "http://127.0.0.1:9090/", nil)
	if !strings.Contains(body, "Authentication is off") {
		t.Error("the page does not explain the empty usage section")
	}
}

func TestDashboardRendersAnEmptyCluster(t *testing.T) {
	// The state a fresh install is in, and the one most likely to be looked at
	// with a template that has never seen it.
	h := Dashboard(emptySource{}, nil, "v1", time.Second, nil)
	code, body := get(t, h, "http://127.0.0.1:9090/", nil)
	if code != http.StatusOK {
		t.Fatalf("status %d", code)
	}
	if !strings.Contains(body, "No agents have registered") {
		t.Error("an empty cluster renders nothing useful")
	}
}

type emptySource struct{}

func (emptySource) Nodes() []adminapi.NodeView             { return nil }
func (emptySource) Models() []adminapi.ModelView           { return nil }
func (emptySource) Replicas(string) []adminapi.ReplicaView { return nil }
func (emptySource) Explain(string) adminapi.ExplainView    { return adminapi.ExplainView{} }

func TestStaticIsNotAFileServer(t *testing.T) {
	// A file server over the embedded templates would also serve the templates,
	// which is harmless today and the kind of thing that stops being harmless.
	h := Static()
	if code, _ := get(t, h, "http://x/_static/base.css", nil); code != http.StatusOK {
		t.Errorf("the stylesheet is not served: %d", code)
	}
	for _, path := range []string{
		"/_static/dashboard.html", "/_static/", "/_static/../web.go",
	} {
		if code, _ := get(t, h, "http://x"+path, nil); code == http.StatusOK {
			t.Errorf("%s was served", path)
		}
	}
}