package httpx_test

import (
	"context"
	"crypto/tls"
	"net"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"git.lohmar.co.uk/cclohmar/NextMyDay/internal/core/httpx"
)

func TestSetAndClearSessionCookie(t *testing.T) {
	rec := httptest.NewRecorder()
	httpx.SetSessionCookie(rec, httpx.SessionCookieName, "abc123", true)

	cookies := rec.Result().Cookies()
	if len(cookies) != 1 {
		t.Fatalf("got %d cookies, want 1", len(cookies))
	}
	c := cookies[0]
	if c.Name != httpx.SessionCookieName || c.Value != "abc123" {
		t.Errorf("cookie = %s=%s", c.Name, c.Value)
	}
	if !c.HttpOnly {
		t.Error("cookie is not HttpOnly")
	}
	if !c.Secure {
		t.Error("cookie is not Secure")
	}
	if c.SameSite != http.SameSiteLaxMode {
		t.Errorf("SameSite = %v, want Lax", c.SameSite)
	}
	if c.Path != "/" {
		t.Errorf("Path = %q, want /", c.Path)
	}

	// Clearing expires it.
	rec2 := httptest.NewRecorder()
	httpx.ClearSessionCookie(rec2, httpx.SessionCookieName, true)
	if got := rec2.Result().Cookies()[0].MaxAge; got >= 0 {
		t.Errorf("cleared cookie MaxAge = %d, want negative", got)
	}
}

func TestParseTrustedProxies(t *testing.T) {
	tp, err := httpx.ParseTrustedProxies([]string{"127.0.0.1", "10.0.0.0/8", ""})
	if err != nil {
		t.Fatalf("ParseTrustedProxies: %v", err)
	}
	if !tp.Contains(parseIP(t, "127.0.0.1")) {
		t.Error("127.0.0.1 not trusted")
	}
	if !tp.Contains(parseIP(t, "10.1.2.3")) {
		t.Error("10.1.2.3 not covered by 10.0.0.0/8")
	}
	if tp.Contains(parseIP(t, "8.8.8.8")) {
		t.Error("8.8.8.8 reported trusted")
	}

	if _, err := httpx.ParseTrustedProxies([]string{"not-an-ip"}); err == nil {
		t.Error("ParseTrustedProxies(bad) = nil, want error")
	}
}

// TestRequestIsHTTPS pins D-043: https is decided by the transport — a direct
// TLS connection, or a TRUSTED proxy's X-Forwarded-Proto. An untrusted peer's
// header is ignored.
func TestRequestIsHTTPS(t *testing.T) {
	tp, _ := httpx.ParseTrustedProxies([]string{"10.0.0.5"})
	newReq := func(peer string, useTLS bool, xfp string) *http.Request {
		r := httptest.NewRequest("GET", "/", nil)
		r.RemoteAddr = peer
		if useTLS {
			r.TLS = &tls.ConnectionState{}
		}
		if xfp != "" {
			r.Header.Set("X-Forwarded-Proto", xfp)
		}
		return r
	}
	cases := []struct {
		name string
		req  *http.Request
		want bool
	}{
		{"direct TLS", newReq("203.0.113.9:4444", true, ""), true},
		{"trusted proxy, XFP https", newReq("10.0.0.5:4444", false, "https"), true},
		{"trusted proxy, XFP http", newReq("10.0.0.5:4444", false, "http"), false},
		{"trusted proxy, no XFP", newReq("10.0.0.5:4444", false, ""), false},
		{"trusted proxy, XFP list", newReq("10.0.0.5:4444", false, "https, http"), true},
		{"untrusted peer spoofs XFP https", newReq("203.0.113.9:4444", false, "https"), false},
		{"loopback peer, no XFP", newReq("127.0.0.1:4444", false, ""), false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			if got := httpx.RequestIsHTTPS(tc.req, tp); got != tc.want {
				t.Errorf("RequestIsHTTPS = %v, want %v", got, tc.want)
			}
		})
	}
}

// TestSecureFromRequestDefaultsFalse pins the transport-neutral default: a
// request that never passed through the door is plain http, so cookie writers
// fall back to the non-Secure (bare) behaviour.
func TestSecureFromRequestDefaultsFalse(t *testing.T) {
	r := httptest.NewRequest("GET", "/", nil)
	if httpx.SecureFromRequest(r) {
		t.Error("SecureFromRequest = true with no door-set value, want false")
	}
	ctx := httpx.WithSecure(r.Context(), true)
	if !httpx.SecureFromRequest(r.WithContext(ctx)) {
		t.Error("SecureFromRequest did not read the door-set value")
	}
}

// TestSetupRequestAllowed pins D-025 (revised): only a loopback TCP peer with
// NO X-Forwarded-For is the direct tunnel; everything else — including a
// loopback peer carrying XFF, or an unparseable peer — fails closed.
func TestSetupRequestAllowed(t *testing.T) {
	cases := []struct {
		name string
		peer string
		xff  string
		want bool
	}{
		{"loopback peer, no XFF", "127.0.0.1:52345", "", true},
		{"loopback peer with XFF", "127.0.0.1:52345", "203.0.113.9", false},
		{"remote peer", "203.0.113.9:4444", "", false},
		{"remote peer with XFF", "203.0.113.9:4444", "198.51.100.7", false},
		{"empty peer", "", "", false},
		{"unparseable peer", "not-an-address", "", false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			r := httptest.NewRequest("GET", "/setup", nil)
			r.RemoteAddr = tc.peer
			if tc.xff != "" {
				r.Header.Set("X-Forwarded-For", tc.xff)
			}
			if got := httpx.SetupRequestAllowed(r); got != tc.want {
				t.Errorf("SetupRequestAllowed = %v, want %v", got, tc.want)
			}
		})
	}
}

func TestClientIPUntrustedPeerIgnoresXFF(t *testing.T) {
	tp, _ := httpx.ParseTrustedProxies([]string{"127.0.0.1"})
	r := httptest.NewRequest("GET", "/", nil)
	r.RemoteAddr = "203.0.113.9:5555"
	r.Header.Set("X-Forwarded-For", "1.2.3.4, 5.6.7.8")

	got := httpx.ClientIP(r, tp)
	if got != "203.0.113.9" {
		t.Errorf("ClientIP = %q, want the peer (XFF from an untrusted peer must be ignored)", got)
	}
	// SET, never append.
	if xff := r.Header.Get("X-Forwarded-For"); xff != "203.0.113.9" {
		t.Errorf("X-Forwarded-For = %q, want it SET to %q", xff, "203.0.113.9")
	}
}

func TestClientIPTrustedPeerResolvesRightmostUntrusted(t *testing.T) {
	tp, _ := httpx.ParseTrustedProxies([]string{"127.0.0.1", "10.0.0.0/8"})
	r := httptest.NewRequest("GET", "/", nil)
	r.RemoteAddr = "127.0.0.1:5555"
	// An append-style proxy (nginx default) appends the peer it SAW to the
	// right of whatever the client sent. Here a client forged "1.2.3.4" and the
	// proxy appended the real client "198.51.100.7" (H1).
	r.Header.Set("X-Forwarded-For", "1.2.3.4, 198.51.100.7, 10.0.0.5")

	got := httpx.ClientIP(r, tp)
	if got != "198.51.100.7" {
		t.Errorf("ClientIP = %q, want the rightmost untrusted 198.51.100.7 (H1: the leftmost entry is forgeable)", got)
	}
	if xff := r.Header.Get("X-Forwarded-For"); xff != "198.51.100.7" {
		t.Errorf("X-Forwarded-For = %q, want it SET (replaced), not appended", xff)
	}
}

// TestClientIPIgnoresForgedLeftmostEntry is the H1 regression: the leftmost
// entry must never win, or an append-style proxy gives the client a fresh
// rate-limit bucket and a forged audit client_ip (A3/A11).
func TestClientIPIgnoresForgedLeftmostEntry(t *testing.T) {
	tp, _ := httpx.ParseTrustedProxies([]string{"127.0.0.1"})
	r := httptest.NewRequest("GET", "/", nil)
	r.RemoteAddr = "127.0.0.1:5555"
	r.Header.Set("X-Forwarded-For", "9.9.9.9, 198.51.100.7")

	if got := httpx.ClientIP(r, tp); got != "198.51.100.7" {
		t.Errorf("ClientIP = %q, want 198.51.100.7 (the forged 9.9.9.9 must be ignored, H1)", got)
	}
}

func TestClientIPAllHopsTrusted(t *testing.T) {
	tp, _ := httpx.ParseTrustedProxies([]string{"127.0.0.1", "10.0.0.0/8"})
	r := httptest.NewRequest("GET", "/", nil)
	r.RemoteAddr = "127.0.0.1:5555"
	r.Header.Set("X-Forwarded-For", "10.0.0.1, 10.0.0.2")

	// Every hop is trusted: the peer is the only address we can vouch for.
	if got := httpx.ClientIP(r, tp); got != "127.0.0.1" {
		t.Errorf("ClientIP = %q, want the peer 127.0.0.1 when every hop is trusted", got)
	}
}

// TestIsLoopbackHost pins the nudge's origin predicate (SPEC-006 §8): a NAME
// is not loopback, and only an empty/unknown host fails closed to loopback.
func TestIsLoopbackHost(t *testing.T) {
	cases := []struct {
		host string
		want bool
	}{
		{"127.0.0.1", true},
		{"127.0.0.1:8080", true},
		{"localhost", true},
		{"localhost:8080", true},
		{"[::1]:8080", true},
		{"example.com", false},
		{"myday.example.com:443", false},
		{"203.0.113.9", false},
		{"", true}, // unknown → suppress the nudge (fail closed)
	}
	for _, tc := range cases {
		if got := httpx.IsLoopbackHost(tc.host); got != tc.want {
			t.Errorf("IsLoopbackHost(%q) = %v, want %v", tc.host, got, tc.want)
		}
	}
}

// TestIsLoopbackIPFailsClosed pins the setup-mode gate's predicate (H2): an
// empty or unparseable resolved client IP must NOT count as loopback.
func TestIsLoopbackIPFailsClosed(t *testing.T) {
	cases := []struct {
		ip   string
		want bool
	}{
		{"127.0.0.1", true},
		{"127.0.0.5", true},
		{"::1", true},
		{"localhost", true},
		{"[::1]", true},
		{"203.0.113.9", false},
		{"10.0.0.5", false},
		{"", false}, // unparseable: fail closed
		{"not-an-ip", false},
		{"0.0.0.0", false},
	}
	for _, tc := range cases {
		if got := httpx.IsLoopbackIP(tc.ip); got != tc.want {
			t.Errorf("IsLoopbackIP(%q) = %v, want %v", tc.ip, got, tc.want)
		}
	}
}

// TestSessionCookieNameForPrefix pins L1s: the `__Host-` prefix is used exactly
// when the cookie is Secure (a browser rejects a `__Host-` cookie over http).
func TestSessionCookieNameForPrefix(t *testing.T) {
	if got := httpx.SessionCookieNameFor(true); got != "__Host-myday_session" {
		t.Errorf("SessionCookieNameFor(true) = %q, want the __Host- prefix", got)
	}
	if got := httpx.SessionCookieNameFor(false); got != httpx.SessionCookieName {
		t.Errorf("SessionCookieNameFor(false) = %q, want the bare name", got)
	}
}

func TestRedactPath(t *testing.T) {
	cases := []struct {
		in       string
		mustGone string
	}{
		{"/setup/token/SUPERSECRETTOKEN", "SUPERSECRETTOKEN"},
		{"/access/reset/SUPERSECRETTOKEN", "SUPERSECRETTOKEN"},
		{"/x/token=SUPERSECRETTOKEN", "SUPERSECRETTOKEN"},
	}
	for _, tc := range cases {
		got := httpx.RedactPath(tc.in)
		if strings.Contains(got, tc.mustGone) {
			t.Errorf("RedactPath(%q) = %q, still contains the credential", tc.in, got)
		}
		if !strings.Contains(got, httpx.Redacted) {
			t.Errorf("RedactPath(%q) = %q, want a %s marker", tc.in, got, httpx.Redacted)
		}
	}

	// The GUID is public and must survive verbatim (D-001).
	const guid = "AbCdEf0123456789"
	if got := httpx.RedactPath("/" + guid + "/home"); got != "/"+guid+"/home" {
		t.Errorf("RedactPath preserved a GUID: got %q", got)
	}
}

func TestRedactQuery(t *testing.T) {
	got := httpx.RedactQuery("token=SECRET&view=open")
	if strings.Contains(got, "SECRET") {
		t.Errorf("RedactQuery = %q, still contains the token", got)
	}
	if !strings.Contains(got, "view=open") {
		t.Errorf("RedactQuery = %q, want the non-sensitive param kept", got)
	}
}

func TestSetSecurityHeaders(t *testing.T) {
	rec := httptest.NewRecorder()
	httpx.SetSecurityHeaders(rec, false)
	h := rec.Header()
	if h.Get("X-Content-Type-Options") != "nosniff" {
		t.Error("missing X-Content-Type-Options: nosniff")
	}
	if h.Get("Referrer-Policy") != "no-referrer" {
		t.Error("missing Referrer-Policy")
	}
	if !strings.Contains(h.Get("Content-Security-Policy"), "default-src 'self'") {
		t.Errorf("CSP = %q", h.Get("Content-Security-Policy"))
	}
	// L4s: the isolation trio.
	if got := h.Get("Permissions-Policy"); !strings.Contains(got, "geolocation=()") {
		t.Errorf("Permissions-Policy = %q, want the feature allowlist", got)
	}
	if got := h.Get("Cross-Origin-Opener-Policy"); got != "same-origin" {
		t.Errorf("Cross-Origin-Opener-Policy = %q, want same-origin", got)
	}
	if got := h.Get("Cross-Origin-Resource-Policy"); got != "same-origin" {
		t.Errorf("Cross-Origin-Resource-Policy = %q, want same-origin", got)
	}
	if h.Get("Strict-Transport-Security") != "" {
		t.Error("HSTS set for an insecure request")
	}

	rec2 := httptest.NewRecorder()
	httpx.SetSecurityHeaders(rec2, true)
	if rec2.Header().Get("Strict-Transport-Security") == "" {
		t.Error("HSTS missing for a secure request")
	}
}

func TestCSRF(t *testing.T) {
	csrf, err := httpx.NewCSRF([]byte("a-test-csrf-key-0123456789abcdef"))
	if err != nil {
		t.Fatalf("NewCSRF: %v", err)
	}

	tok := csrf.Token("session-1")
	if tok == "" {
		t.Fatal("Token returned empty")
	}
	if !csrf.Valid("session-1", tok) {
		t.Error("Valid rejected the correct token")
	}
	if csrf.Valid("session-2", tok) {
		t.Error("Valid accepted a token bound to another session")
	}
	if csrf.Valid("session-1", "") {
		t.Error("Valid accepted an empty token")
	}
	if csrf.Valid("", tok) {
		t.Error("Valid accepted an empty session id")
	}
	if csrf.Valid("session-1", tok+"x") {
		t.Error("Valid accepted a tampered token")
	}

	if _, err := httpx.NewCSRF(nil); err == nil {
		t.Error("NewCSRF(nil) = nil, want an error (fail closed)")
	}
}

func TestTokenContext(t *testing.T) {
	ctx := httpx.WithToken(context.Background(), "tok-9")
	if got := httpx.TokenFrom(ctx); got != "tok-9" {
		t.Errorf("TokenFrom = %q, want tok-9", got)
	}
	if got := httpx.TokenFrom(context.Background()); got != "" {
		t.Errorf("TokenFrom(background) = %q, want empty", got)
	}
}

func parseIP(t *testing.T, s string) (ip net.IP) {
	t.Helper()
	ip = net.ParseIP(s)
	if ip == nil {
		t.Fatalf("ParseIP(%q) = nil", s)
	}
	return ip
}