package haproxy

import (
	"bytes"
	"strings"
	"testing"

	"git.netcell-it.de/projekte/edgeguard-native/internal/models"
)

func renderView(t *testing.T, v View) string {
	t.Helper()
	var buf bytes.Buffer
	if err := tpl.Execute(&buf, v); err != nil {
		t.Fatalf("template execute: %v", err)
	}
	return buf.String()
}

func mkBackend(id int64, name string, hcp *string) models.Backend {
	return models.Backend{
		ID: id, Name: name, Scheme: "http",
		LBAlgorithm: "roundrobin", Active: true,
		HealthCheckPath: hcp,
	}
}

func mkServer(backendID int64, name, addr string, port int) models.BackendServer {
	return models.BackendServer{
		BackendID: backendID, Name: name, Address: addr, Port: port,
		Weight: 100, Active: true,
	}
}

func TestRender_BaselineHasFrontendsAndApiBackend(t *testing.T) {
	out := renderView(t, View{})
	for _, w := range []string{
		"frontend public_http",
		"frontend public_https",
		"frontend internal_stats",
		"backend api_backend",
		"server api1 127.0.0.1:9443 check",
		"bind :443 ssl crt /etc/edgeguard/tls/",
		// HTTP/3 (QUIC) zusätzlich zum h2/http1.1-Listener.
		"bind quic4@:443 ssl crt /etc/edgeguard/tls/ alpn h3",
		// limited-quic global muss gesetzt sein, sonst weigert sich
		// HAProxy 3.0 das quic4-bind anzunehmen (OpenSSL-Kompat-Layer).
		"limited-quic",
		// Alt-Svc damit Browser auf h3 upgraden.
		`Alt-Svc "h3=\":443\"; ma=86400"`,
		"path_beg /.well-known/acme-challenge/",
		"http-request redirect scheme https",
		// Client-IP-Weiterleitung an Backends — XFF kommt aus
		// defaults (option forwardfor), Proto + RealIP setzen wir
		// pro public-Frontend explizit.
		"option  forwardfor",
		"http-request set-header X-Forwarded-Proto https",
		"http-request set-header X-Real-IP %[src]",
	} {
		if !strings.Contains(out, w) {
			t.Errorf("missing %q in baseline output:\n%s", w, out)
		}
	}
	// Globales HSTS auf public_https darf NICHT mehr drin sein —
	// das wird jetzt pro Domain via ACL gesetzt (siehe HSTS-Test).
	// mgmt_https hat aber weiterhin ein globales HSTS.
	publicIdx := strings.Index(out, "frontend public_https")
	mgmtIdx := strings.Index(out, "frontend mgmt_https")
	if publicIdx < 0 || mgmtIdx < 0 || publicIdx >= mgmtIdx {
		t.Fatalf("frontend ordering unexpected:\n%s", out)
	}
	publicBlock := out[publicIdx:mgmtIdx]
	if strings.Contains(publicBlock, "set-header Strict-Transport-Security") {
		t.Errorf("public_https soll KEIN globales HSTS mehr enthalten (pro-Domain ACL):\n%s", publicBlock)
	}
}

func TestRender_HSTSPerDomain(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{
					ID: 1, Name: "a.example.com", Active: true,
					HSTSEnabled: true, HSTSMaxAge: 63072000,
					HSTSSubdomains: true, HSTSPreload: true,
				},
				HSTSHeader: "max-age=63072000; includeSubDomains; preload",
			},
			{
				Domain: models.Domain{
					ID: 2, Name: "b.example.com", Active: true,
					HSTSEnabled: false,
				},
			},
		},
	}
	out := renderView(t, v)
	for _, w := range []string{
		// Erst löschen (gegen Backend-set HSTS), dann setzen.
		`http-response del-header Strict-Transport-Security if { hdr(host) -i a.example.com }`,
		`http-response set-header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" if { hdr(host) -i a.example.com }`,
	} {
		if !strings.Contains(out, w) {
			t.Errorf("missing %q in per-domain HSTS output:\n%s", w, out)
		}
	}
	// HSTS soll für die Domain ohne HSTSEnabled gar nicht erst gerendert
	// werden: keine einzige HSTS-Zeile darf sich auf b.example.com beziehen.
	for _, line := range strings.Split(out, "\n") {
		if strings.Contains(line, "Strict-Transport-Security") &&
			strings.Contains(line, "hdr(host) -i b.example.com") {
			t.Errorf("unexpected HSTS ACL for HSTS-disabled domain b.example.com: %q", line)
		}
	}
}

func TestRender_MaintenanceModeBlocksWith503(t *testing.T) {
	msg := `Wartung — bitte später wiederkommen.`
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{
					ID: 1, Name: "down.example.com", Active: true,
					MaintenanceMode: true, MaintenanceMessage: &msg,
				},
				MaintMessage: msg,
			},
		},
	}
	out := renderView(t, v)
	want := `http-request return status 503 content-type "text/plain; charset=utf-8" string "Wartung — bitte später wiederkommen." if { hdr(host) -i down.example.com }`
	if !strings.Contains(out, want) {
		t.Errorf("missing maintenance-503 line:\n%s", out)
	}
}

func TestRender_WWWRedirectToNaked(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{
					ID: 1, Name: "example.com", Active: true,
					WWWRedirect: "to-naked",
				},
				RedirectFromHost: "www.example.com",
			},
		},
	}
	out := renderView(t, v)
	want := `http-request redirect prefix https://example.com code 301 if { hdr(host) -i www.example.com }`
	if !strings.Contains(out, want) {
		t.Errorf("missing www→naked redirect line:\n%s", out)
	}
}

func TestRender_WWWRedirectToWWW(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{
					ID: 1, Name: "www.example.com", Active: true,
					WWWRedirect: "to-www",
				},
				RedirectFromHost: "example.com",
			},
		},
	}
	out := renderView(t, v)
	want := `http-request redirect prefix https://www.example.com code 301 if { hdr(host) -i example.com }`
	if !strings.Contains(out, want) {
		t.Errorf("missing naked→www redirect line:\n%s", out)
	}
}

func TestRender_RedirectTo(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{
					ID: 1, Name: "kvs.netcell-it.de", Active: true,
					RedirectTo: "https://zkm.netcell-it.de",
				},
				RedirectTo: "https://zkm.netcell-it.de",
			},
		},
	}
	out := renderView(t, v)
	want := `http-request redirect location https://zkm.netcell-it.de code 301 if { hdr(host) -i kvs.netcell-it.de }`
	if !strings.Contains(out, want) {
		t.Errorf("missing domain→domain 301 redirect line:\n%s", out)
	}
}

func TestBuildRedirectTo(t *testing.T) {
	cases := []struct{ in, want string }{
		{"https://zkm.netcell-it.de", "https://zkm.netcell-it.de"},
		{"  https://zkm.netcell-it.de  ", "https://zkm.netcell-it.de"}, // getrimmt
		{"http://x.de", "http://x.de"},
		{"", ""},
		{"zkm.netcell-it.de", ""},           // kein Schema
		{"ftp://x.de", ""},                  // falsches Schema
		{"https://x .de", ""},               // Whitespace → unsafe
		{"https://x\"de", ""},               // Quote → unsafe
		{"javascript:alert(1)", ""},         // kein http(s)
	}
	for _, c := range cases {
		got := buildRedirectTo(models.Domain{RedirectTo: c.in})
		if got != c.want {
			t.Errorf("buildRedirectTo(%q) = %q, want %q", c.in, got, c.want)
		}
	}
}

func TestBuildHSTSHeader(t *testing.T) {
	cases := []struct {
		name string
		d    models.Domain
		want string
	}{
		{"disabled", models.Domain{HSTSEnabled: false}, ""},
		{"defaults", models.Domain{HSTSEnabled: true}, "max-age=31536000"},
		{"explicit", models.Domain{HSTSEnabled: true, HSTSMaxAge: 7200}, "max-age=7200"},
		{"sub", models.Domain{HSTSEnabled: true, HSTSMaxAge: 60, HSTSSubdomains: true}, "max-age=60; includeSubDomains"},
		{"sub+preload", models.Domain{HSTSEnabled: true, HSTSMaxAge: 60, HSTSSubdomains: true, HSTSPreload: true}, "max-age=60; includeSubDomains; preload"},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			if got := buildHSTSHeader(tc.d); got != tc.want {
				t.Errorf("buildHSTSHeader: got %q want %q", got, tc.want)
			}
		})
	}
}

func TestBuildMaintMessage(t *testing.T) {
	msg := `He said "hi"` + "\n" + `and left`
	d := models.Domain{MaintenanceMode: true, MaintenanceMessage: &msg}
	got := buildMaintMessage(d)
	// Quotes durch ' ersetzt, Newline → Space.
	want := `He said 'hi' and left`
	if got != want {
		t.Errorf("buildMaintMessage: got %q want %q", got, want)
	}
	if buildMaintMessage(models.Domain{MaintenanceMode: false}) != "" {
		t.Errorf("buildMaintMessage should be empty when MaintenanceMode is off")
	}
	if got := buildMaintMessage(models.Domain{MaintenanceMode: true}); got == "" {
		t.Errorf("buildMaintMessage should emit fallback text when no message set")
	}
}

func TestRender_GlobalMaintenanceBlocksAllCustomerTraffic(t *testing.T) {
	v := View{
		GlobalMaintenance:        true,
		GlobalMaintenanceMessage: "Wartung läuft.",
		Domains: []DomainView{
			{Domain: models.Domain{ID: 1, Name: "site.example.com", Active: true}},
		},
	}
	out := renderView(t, v)
	want := `http-request return status 503 content-type "text/plain; charset=utf-8" string "Wartung läuft."`
	if !strings.Contains(out, want) {
		t.Errorf("missing global-maintenance 503 block:\n%s", out)
	}
	// Block muss VOR den use_backend-Zeilen IM SELBEN public_https-
	// Frontend stehen (sonst ineffektiv — HAProxy execut'ed in-order,
	// return-actions terminieren die Chain). public_http hat ein
	// frühes use_backend api_backend für ACME — das hier nicht
	// matchen.
	pubIdx := strings.Index(out, "frontend public_https")
	mgmtIdxStart := strings.Index(out, "frontend mgmt_https")
	if pubIdx < 0 || mgmtIdxStart < 0 {
		t.Fatalf("frontends not found in output:\n%s", out)
	}
	publicBlock := out[pubIdx:mgmtIdxStart]
	idxBlock := strings.Index(publicBlock, want)
	idxUseBackend := strings.Index(publicBlock, "use_backend")
	if idxBlock < 0 || (idxUseBackend > 0 && idxBlock > idxUseBackend) {
		t.Errorf("global-maintenance block must precede use_backend in public_https\n  block at %d, use_backend at %d", idxBlock, idxUseBackend)
	}
	// mgmt_https darf NICHT betroffen sein.
	mgmtIdx := strings.Index(out, "frontend mgmt_https")
	if mgmtIdx > 0 {
		mgmtBlock := out[mgmtIdx:]
		if strings.Contains(mgmtBlock, want) {
			t.Errorf("mgmt_https must NOT contain global-maintenance block:\n%s", mgmtBlock)
		}
	}
}

func TestRender_GlobalMaintenanceOff_NoBlock(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{Domain: models.Domain{ID: 1, Name: "site.example.com", Active: true}},
		},
	}
	out := renderView(t, v)
	if strings.Contains(out, "Whole-Box-Maintenance") {
		t.Errorf("global-maintenance comment should not be rendered when off:\n%s", out)
	}
}

func TestRender_RateLimitEmitsStickTableAndDeny(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{
					ID: 7, Name: "api.example.com", Active: true,
					RateLimitRPS: 50,
				},
				RateLimitThreshold: 500, // 50 rps × 10s
			},
		},
	}
	out := renderView(t, v)
	for _, w := range []string{
		"backend rl_7",
		"stick-table type ip size 100k expire 10s store http_req_rate(10s)",
		`http-request track-sc0 src table rl_7 if { hdr(host) -i api.example.com }`,
		`http-request deny deny_status 429 if { hdr(host) -i api.example.com } { sc_http_req_rate(0) gt 500 }`,
	} {
		if !strings.Contains(out, w) {
			t.Errorf("missing %q in rate-limit output:\n%s", w, out)
		}
	}
}

func TestRender_NoRateLimitNoStickTable(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{ID: 9, Name: "a.example.com", Active: true},
			},
		},
	}
	out := renderView(t, v)
	if strings.Contains(out, "backend rl_9") {
		t.Errorf("stick-table backend rendered for domain without rate-limit:\n%s", out)
	}
	if strings.Contains(out, "track-sc0") {
		t.Errorf("track-sc0 emitted without rate-limit:\n%s", out)
	}
}

func TestRender_BodySizeDeny413(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{
					ID: 1, Name: "upload.example.com", Active: true,
					MaxBodyKB: 2048,
				},
				MaxBodyBytes: 2048 * 1024,
			},
		},
	}
	out := renderView(t, v)
	want := `http-request deny deny_status 413 if { hdr(host) -i upload.example.com } { req.hdr_val(content-length) -m int gt 2097152 }`
	if !strings.Contains(out, want) {
		t.Errorf("missing 413 body-size deny:\n%s", out)
	}
}

func TestRender_CustomResponseHeaders(t *testing.T) {
	v := View{
		Domains: []DomainView{
			{
				Domain: models.Domain{ID: 1, Name: "x.example.com", Active: true},
				ResponseHeaders: []ResponseHeaderView{
					{Name: "X-Frame-Options", Value: "DENY"},
					{Name: "Content-Security-Policy", Value: "default-src 'self'"},
				},
			},
		},
	}
	out := renderView(t, v)
	for _, w := range []string{
		// del + set pro Custom-Header, damit Upstream-Werte
		// garantiert überschrieben werden.
		`http-response del-header X-Frame-Options if { hdr(host) -i x.example.com }`,
		`http-response set-header X-Frame-Options "DENY" if { hdr(host) -i x.example.com }`,
		`http-response del-header Content-Security-Policy if { hdr(host) -i x.example.com }`,
		`http-response set-header Content-Security-Policy "default-src 'self'" if { hdr(host) -i x.example.com }`,
	} {
		if !strings.Contains(out, w) {
			t.Errorf("missing %q:\n%s", w, out)
		}
	}
}

func TestSanitizeHeaderValue(t *testing.T) {
	cases := map[string]string{
		`plain`:              `plain`,
		`with "quotes"`:      `with 'quotes'`,
		"with\nnewline":      "with newline",
		"crlf\r\nattack":     "crlf  attack",
		`csp default-src 'self'`: `csp default-src 'self'`,
	}
	for in, want := range cases {
		if got := sanitizeHeaderValue(in); got != want {
			t.Errorf("sanitizeHeaderValue(%q) = %q want %q", in, got, want)
		}
	}
}

func TestBuildRedirectFromHost(t *testing.T) {
	cases := []struct {
		name string
		d    models.Domain
		want string
	}{
		{"none", models.Domain{Name: "example.com"}, ""},
		{"to-naked", models.Domain{Name: "example.com", WWWRedirect: "to-naked"}, "www.example.com"},
		{"to-naked invalid (name already has www)", models.Domain{Name: "www.example.com", WWWRedirect: "to-naked"}, ""},
		{"to-www", models.Domain{Name: "www.example.com", WWWRedirect: "to-www"}, "example.com"},
		{"to-www invalid (name lacks www)", models.Domain{Name: "example.com", WWWRedirect: "to-www"}, ""},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			if got := buildRedirectFromHost(tc.d); got != tc.want {
				t.Errorf("buildRedirectFromHost: got %q want %q", got, tc.want)
			}
		})
	}
}

func TestRender_DomainRoutesEmitUseBackend(t *testing.T) {
	v := View{
		Backends: []BackendView{
			{Backend: mkBackend(1, "app", nil), Servers: []models.BackendServer{
				mkServer(1, "app", "10.0.0.10", 8080),
			}},
			{Backend: mkBackend(2, "api", nil), Servers: []models.BackendServer{
				mkServer(2, "api", "10.0.0.20", 9000),
			}},
		},
		Domains: []DomainView{{
			Domain: models.Domain{ID: 1, Name: "example.com", Active: true},
			Routes: []RouteView{
				{PathPrefix: "/", BackendID: 1},
				{PathPrefix: "/api", BackendID: 2},
			},
		}},
	}
	out := renderView(t, v)
	for _, w := range []string{
		"backend eg_backend_1",
		"server app 10.0.0.10:8080",
		"backend eg_backend_2",
		"server api 10.0.0.20:9000",
		"balance roundrobin",
		"use_backend eg_backend_1 if { hdr(host) -i example.com } { path_beg / }",
		"use_backend eg_backend_2 if { hdr(host) -i example.com } { path_beg /api }",
	} {
		if !strings.Contains(out, w) {
			t.Errorf("missing %q in output:\n%s", w, out)
		}
	}
}

func TestRender_HealthCheckPathAddsCheckInter(t *testing.T) {
	hcp := "/health"
	v := View{
		Backends: []BackendView{
			{Backend: mkBackend(1, "app", &hcp), Servers: []models.BackendServer{
				mkServer(1, "app", "10.0.0.10", 8080),
			}},
		},
	}
	out := renderView(t, v)
	if !strings.Contains(out, "server app 10.0.0.10:8080 check inter 5s") {
		t.Errorf("expected `check inter 5s` for backend with health_check_path:\n%s", out)
	}
	if !strings.Contains(out, "option httpchk") {
		t.Errorf("expected `option httpchk` when health_check_path set:\n%s", out)
	}
}

func TestRender_HTTPSHealthcheckPinsAlpnHTTP1(t *testing.T) {
	// L7TOUT-Bug: ohne `check-alpn http/1.1` handelt der Check h2
	// aus (vom server-Stmt geerbt) und hängt, weil option httpchk
	// HTTP/1.x sendet. Test stellt sicher dass HTTPS+Healthcheck
	// das ALPN für den Check pinnt.
	hcp := "/"
	v := View{
		Backends: []BackendView{
			{
				Backend: models.Backend{ID: 9, Name: "tls-app", Scheme: "https",
					LBAlgorithm: "roundrobin", HealthCheckPath: &hcp, Active: true},
				Servers: []models.BackendServer{
					{BackendID: 9, Name: "tls-1", Address: "10.0.0.30", Port: 8443, Weight: 100, Active: true},
				},
			},
			{
				// Gegenprobe: HTTP-Backend mit Healthcheck darf KEIN
				// check-alpn bekommen (ALPN gibt's nur bei SSL).
				Backend: models.Backend{ID: 10, Name: "plain-app", Scheme: "http",
					LBAlgorithm: "roundrobin", HealthCheckPath: &hcp, Active: true},
				Servers: []models.BackendServer{
					{BackendID: 10, Name: "plain-1", Address: "10.0.0.31", Port: 80, Weight: 100, Active: true},
				},
			},
		},
	}
	out := renderView(t, v)
	idxTLS := strings.Index(out, "backend eg_backend_9")
	idxPlain := strings.Index(out, "backend eg_backend_10")
	if idxTLS < 0 || idxPlain < 0 {
		t.Fatalf("backend sections missing:\n%s", out)
	}
	tlsBlock := out[idxTLS:idxPlain]
	plainBlock := out[idxPlain:]
	if !strings.Contains(tlsBlock, "check-alpn http/1.1") {
		t.Errorf("HTTPS+healthcheck soll check-alpn http/1.1 pinnen:\n%s", tlsBlock)
	}
	if strings.Contains(plainBlock, "check-alpn") {
		t.Errorf("HTTP-Backend darf KEIN check-alpn bekommen:\n%s", plainBlock)
	}
}

func TestRender_WebSocketEmitsTunnelTimeout(t *testing.T) {
	v := View{
		Backends: []BackendView{
			{
				Backend: models.Backend{ID: 7, Name: "vmm", Scheme: "https",
					LBAlgorithm: "source", WebSocket: true, Active: true},
				Servers: []models.BackendServer{
					{BackendID: 7, Name: "vmm-1", Address: "10.0.5.14", Port: 8006, Weight: 100, Active: true},
				},
			},
			{
				Backend: models.Backend{ID: 8, Name: "api", Scheme: "http",
					LBAlgorithm: "roundrobin", WebSocket: false, Active: true},
				Servers: []models.BackendServer{
					{BackendID: 8, Name: "api-1", Address: "10.0.5.20", Port: 8080, Weight: 100, Active: true},
				},
			},
		},
	}
	out := renderView(t, v)
	// vmm soll tunnel-Timeout haben, api nicht.
	idxVmm := strings.Index(out, "backend eg_backend_7")
	idxApi := strings.Index(out, "backend eg_backend_8")
	if idxVmm < 0 || idxApi < 0 {
		t.Fatalf("backend sections missing in output:\n%s", out)
	}
	vmmBlock := out[idxVmm:idxApi]
	apiBlock := out[idxApi:]
	if !strings.Contains(vmmBlock, "timeout tunnel 1h") {
		t.Errorf("vmm-Block sollte `timeout tunnel 1h` enthalten:\n%s", vmmBlock)
	}
	if strings.Contains(apiBlock, "timeout tunnel") {
		t.Errorf("api-Block soll KEIN `timeout tunnel` enthalten:\n%s", apiBlock)
	}
}

func TestRender_MultiServerPool(t *testing.T) {
	v := View{
		Backends: []BackendView{
			{
				Backend: models.Backend{ID: 1, Name: "vmm", Scheme: "http", LBAlgorithm: "leastconn", Active: true},
				Servers: []models.BackendServer{
					{BackendID: 1, Name: "vmm-1", Address: "10.0.0.11", Port: 8080, Weight: 100, Active: true},
					{BackendID: 1, Name: "vmm-2", Address: "10.0.0.12", Port: 8080, Weight: 100, Active: true},
					{BackendID: 1, Name: "vmm-3", Address: "10.0.0.13", Port: 8080, Weight: 50, Backup: true, Active: true},
				},
			},
		},
	}
	out := renderView(t, v)
	for _, w := range []string{
		"backend eg_backend_1",
		"balance leastconn",
		"server vmm-1 10.0.0.11:8080",
		"server vmm-2 10.0.0.12:8080",
		"server vmm-3 10.0.0.13:8080",
		"weight 50",
		" backup",
	} {
		if !strings.Contains(out, w) {
			t.Errorf("missing %q in multi-server output:\n%s", w, out)
		}
	}
}