package agentapi

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"errors"
	"fmt"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

// fakeProber scripts the capability probe (the SupportProber seam) and counts calls.
type fakeProber struct {
	err   error
	calls int
}

func (f *fakeProber) NetVerifyStatus(context.Context) (NetVerifyStatus, error) {
	f.calls++
	return NetVerifyStatus{Phase: "none"}, f.err
}

// --- T4: probe classification — ONLY a typed 404 means "too old" -------------------------------
// Companion red-proof (the classification trap): mutate classifySupportErr to string-match
// "HTTP 404" → the "plain error with 404 text" case classifies No → FAIL. A second mutant treating
// ANY error as SupportNo fails every Unknown case here (and T3 in web).
func TestSupports_Classification(t *testing.T) {
	cases := []struct {
		name string
		err  error
		want SupportState
	}{
		{"2xx (nil error)", nil, SupportYes},
		{"typed 404", &StatusError{Path: "/netstorage/verify-status", Code: http.StatusNotFound}, SupportNo},
		{"typed 404 wrapped", fmt.Errorf("probe: %w", &StatusError{Path: "/x", Code: 404}), SupportNo},
		{"typed 401", &StatusError{Path: "/x", Code: http.StatusUnauthorized}, SupportUnknown},
		{"typed 500", &StatusError{Path: "/x", Code: http.StatusInternalServerError}, SupportUnknown},
		{"typed 502", &StatusError{Path: "/x", Code: http.StatusBadGateway}, SupportUnknown},
		{"connection refused", errors.New("dial tcp 10.0.0.9:8443: connect: connection refused"), SupportUnknown},
		{"timeout", context.DeadlineExceeded, SupportUnknown},
		// The string-matching trap: the OLD untyped error text carries "HTTP 404" but is NOT a
		// *StatusError — a classifier that matches the message would wrongly say "too old".
		{"plain error with 404 text", errors.New("agentapi: GET /netstorage/verify-status: HTTP 404"), SupportUnknown},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			sc := &SupportCache{}
			got := sc.Supports(context.Background(), &fakeProber{err: tc.err}, FeatureNetstorageVerify)
			if got != tc.want {
				t.Errorf("Supports(%v) = %v, want %v", tc.err, got, tc.want)
			}
		})
	}
}

// Unknown feature names must never refuse (a table gap fails open).
func TestSupports_UnknownFeature(t *testing.T) {
	sc := &SupportCache{}
	p := &fakeProber{}
	if got := sc.Supports(context.Background(), p, Feature("no_such_feature")); got != SupportUnknown {
		t.Errorf("unknown feature = %v, want SupportUnknown", got)
	}
	if p.calls != 0 {
		t.Errorf("unknown feature must not probe (calls=%d)", p.calls)
	}
}

// --- T6: cache TTL — both polarities cached; Unknown NEVER cached ------------------------------
// Companion red-proof: drop the TTL expiry check (treat every entry as fresh) → the
// "re-probes after TTL" assertion fails. Dropping the cache entirely → the warm-cache negative
// assertion (calls stays 1) fails (T2's red-proof shape).
func TestSupports_CacheTTL(t *testing.T) {
	t.Run("positive cached, re-probes after TTL", func(t *testing.T) {
		now := time.Date(2026, 7, 11, 12, 0, 0, 0, time.UTC)
		sc := &SupportCache{now: func() time.Time { return now }}
		p := &fakeProber{} // nil err → Yes
		if got := sc.Supports(context.Background(), p, FeatureNetstorageVerify); got != SupportYes {
			t.Fatalf("first = %v, want Yes", got)
		}
		if got := sc.Supports(context.Background(), p, FeatureNetstorageVerify); got != SupportYes {
			t.Fatalf("warm = %v, want Yes", got)
		}
		if p.calls != 1 { // the NEGATIVE assertion: a warm cache must NOT re-probe
			t.Errorf("probe calls on a warm cache = %d, want 1", p.calls)
		}
		now = now.Add(supportTTL + time.Second)
		if got := sc.Supports(context.Background(), p, FeatureNetstorageVerify); got != SupportYes {
			t.Fatalf("post-TTL = %v, want Yes", got)
		}
		if p.calls != 2 {
			t.Errorf("probe calls after TTL expiry = %d, want 2 (must re-fire)", p.calls)
		}
	})
	t.Run("negative cached too", func(t *testing.T) {
		now := time.Date(2026, 7, 11, 12, 0, 0, 0, time.UTC)
		sc := &SupportCache{now: func() time.Time { return now }}
		p := &fakeProber{err: &StatusError{Path: "/x", Code: 404}}
		for i := 0; i < 2; i++ {
			if got := sc.Supports(context.Background(), p, FeatureNetstorageVerify); got != SupportNo {
				t.Fatalf("call %d = %v, want No", i, got)
			}
		}
		if p.calls != 1 {
			t.Errorf("negative verdict not cached (calls=%d, want 1)", p.calls)
		}
	})
	t.Run("unknown never cached", func(t *testing.T) {
		sc := &SupportCache{}
		p := &fakeProber{err: errors.New("connection refused")}
		for i := 0; i < 2; i++ {
			if got := sc.Supports(context.Background(), p, FeatureNetstorageVerify); got != SupportUnknown {
				t.Fatalf("call %d = %v, want Unknown", i, got)
			}
		}
		if p.calls != 2 {
			t.Errorf("Unknown must re-probe every call (calls=%d, want 2)", p.calls)
		}
	})
}

// --- 1.1 wire-level: a real HTTP 404 through Client.get IS the typed StatusError ----------------
// This pins the verify-first finding: an agent without the route (≤0.80's plain mux 404) reaches
// classifySupportErr as *StatusError{404}, end-to-end through the pinned-TLS client.
func TestClient_404IsTypedAndSupportsSaysNo(t *testing.T) {
	mux := http.NewServeMux() // NO /netstorage/verify-status route — the ≤0.80 shape
	srv := httptest.NewTLSServer(mux)
	defer srv.Close()
	fp := sha256.Sum256(srv.Certificate().Raw)
	c, err := New(strings.TrimPrefix(srv.URL, "https://"), "test-token", hex.EncodeToString(fp[:]))
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	_, verr := c.NetVerifyStatus(context.Background())
	var se *StatusError
	if !errors.As(verr, &se) || se.Code != http.StatusNotFound {
		t.Fatalf("404 must surface as *StatusError{404}, got %T: %v", verr, verr)
	}
	if got := c.Supports(context.Background(), FeatureNetstorageVerify); got != SupportNo {
		t.Errorf("Supports on a routeless agent = %v, want SupportNo", got)
	}
}

// The supported shape: the route answers the envelope → Supports says Yes.
func TestClient_SupportsYesOnLiveRoute(t *testing.T) {
	mux := http.NewServeMux()
	mux.HandleFunc("/netstorage/verify-status", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"ok":true,"data":{"phase":"none"}}`)) // the no-job envelope
	})
	srv := httptest.NewTLSServer(mux)
	defer srv.Close()
	fp := sha256.Sum256(srv.Certificate().Raw)
	c, err := New(strings.TrimPrefix(srv.URL, "https://"), "test-token", hex.EncodeToString(fp[:]))
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	if got := c.Supports(context.Background(), FeatureNetstorageVerify); got != SupportYes {
		t.Errorf("Supports on a live route = %v, want SupportYes", got)
	}
}