package infra

import (
	"net"
	"strings"
	"testing"

	"gopkg.in/yaml.v3"
)

// R-753: the fixed tunnel address must sit inside its subnet, apart from the gateway, inside 172.16.0.0/12 (so apps that
// count private addresses as proxies skip it) and OUTSIDE docker's default pools (172.17.0.0/16 … 172.31.0.0/16,
// 192.168.0.0/16), so docker never gives it to an app network.
func TestTunnelConstantsAgree(t *testing.T) {
	_, sub, err := net.ParseCIDR(TunnelSubnet)
	if err != nil {
		t.Fatal(err)
	}
	addr, gw, tr := net.ParseIP(TunnelAddr), net.ParseIP(TunnelGateway), net.ParseIP(TunnelTraefikAddr)
	if !sub.Contains(addr) || !sub.Contains(gw) || !sub.Contains(tr) || addr.Equal(gw) || addr.Equal(tr) || tr.Equal(gw) {
		t.Fatalf("cloudflared %s / traefik %s / gateway %s must be inside %s and differ", TunnelAddr, TunnelTraefikAddr, TunnelGateway, TunnelSubnet)
	}
	// docker's own allocation (TunnelIPRange) must never reach the two fixed addresses — measured: traefik joining
	// first was given .2 by the allocator when no range was set.
	_, rng, err := net.ParseCIDR(TunnelIPRange)
	if err != nil || rng.Contains(addr) || rng.Contains(tr) || !sub.Contains(rng.IP) {
		t.Fatalf("ip-range %s must lie in %s and exclude %s and %s", TunnelIPRange, TunnelSubnet, TunnelAddr, TunnelTraefikAddr)
	}
	_, private, _ := net.ParseCIDR("172.16.0.0/12")
	if !private.Contains(addr) {
		t.Fatalf("%s is not in 172.16.0.0/12", TunnelAddr)
	}
	for _, pool := range []string{"172.17.0.0/16", "172.18.0.0/16", "172.24.0.0/16", "172.31.0.0/16", "192.168.0.0/16"} {
		_, p, _ := net.ParseCIDR(pool)
		if p.Contains(sub.IP) {
			t.Fatalf("%s overlaps docker's default pool %s", TunnelSubnet, pool)
		}
	}
}

func staticEntry(t *testing.T, yml string) map[string]any {
	t.Helper()
	var doc map[string]any
	if err := yaml.Unmarshal([]byte(yml), &doc); err != nil {
		t.Fatalf("traefik.yml is not YAML: %v\n%s", err, yml)
	}
	return doc["entryPoints"].(map[string]any)["websecure"].(map[string]any)
}

// traefik believes forwarded headers from EXACTLY the tunnel address — never `insecure`, never a range — and every
// websecure request passes the clean-up middleware. Without the network (Tunnel false) it trusts nobody.
func TestRenderTraefik_TrustsOnlyTheTunnel(t *testing.T) {
	for _, email := range []string{"", "owner@example.com"} {
		on, err := RenderTraefik(TraefikData{ACMEEmail: email, Tunnel: true})
		if err != nil {
			t.Fatal(err)
		}
		ws := staticEntry(t, on["traefik.yml"].Content)
		fh, ok := ws["forwardedHeaders"].(map[string]any)
		if !ok {
			t.Fatalf("Tunnel: no forwardedHeaders on websecure:\n%s", on["traefik.yml"].Content)
		}
		ips, _ := fh["trustedIPs"].([]any)
		if len(ips) != 1 || ips[0] != TunnelAddr+"/32" || fh["insecure"] != nil {
			t.Fatalf("Tunnel: trust must be exactly [%s/32], got %v (insecure %v)", TunnelAddr, ips, fh["insecure"])
		}
		mw := ws["http"].(map[string]any)["middlewares"].([]any)
		if len(mw) != 1 || mw[0] != ForwardedMiddleware+"@file" {
			t.Fatalf("websecure middlewares = %v", mw)
		}
		if (email != "") != strings.Contains(on["traefik.yml"].Content, "certResolver: letsencrypt") {
			t.Fatalf("the resolver must follow the e-mail (%q)", email)
		}
		var cdoc map[string]any
		if err := yaml.Unmarshal([]byte(on["docker-compose.yml"].Content), &cdoc); err != nil {
			t.Fatalf("traefik compose is not YAML: %v", err)
		}
		tn := cdoc["services"].(map[string]any)["traefik"].(map[string]any)["networks"].(map[string]any)
		if _, ok := tn["traefik-public"]; !ok || tn[TunnelNetwork].(map[string]any)["ipv4_address"] != TunnelTraefikAddr {
			t.Fatalf("Tunnel: traefik must keep traefik-public and sit at %s on %s, got %v", TunnelTraefikAddr, TunnelNetwork, tn)
		}
		if cdoc["networks"].(map[string]any)[TunnelNetwork].(map[string]any)["external"] != true {
			t.Fatalf("Tunnel: %s must be external", TunnelNetwork)
		}

		off, _ := RenderTraefik(TraefikData{ACMEEmail: email})
		ws = staticEntry(t, off["traefik.yml"].Content)
		if ws["forwardedHeaders"] != nil || strings.Contains(off["docker-compose.yml"].Content, TunnelNetwork) {
			t.Fatalf("no tunnel network → no trust and no network:\n%s", off["traefik.yml"].Content)
		}
		if mw := ws["http"].(map[string]any)["middlewares"].([]any); len(mw) != 1 {
			t.Fatalf("the clean-up middleware applies without the tunnel too, got %v", mw)
		}
	}
}

func TestRenderCloudflared_AloneOnTheTunnel(t *testing.T) {
	on, _ := RenderCloudflared(CloudflaredData{CFTunnelToken: "t", Tunnel: true})
	c := on["docker-compose.yml"].Content
	var doc map[string]any
	if err := yaml.Unmarshal([]byte(c), &doc); err != nil {
		t.Fatalf("compose is not YAML: %v\n%s", err, c)
	}
	nets := doc["services"].(map[string]any)["cloudflared"].(map[string]any)["networks"].(map[string]any)
	if len(nets) != 1 || nets[TunnelNetwork].(map[string]any)["ipv4_address"] != TunnelAddr {
		t.Fatalf("cloudflared must be ONLY on %s at %s, got %v", TunnelNetwork, TunnelAddr, nets)
	}
	off, _ := RenderCloudflared(CloudflaredData{CFTunnelToken: "t"})
	if strings.Contains(off["docker-compose.yml"].Content, TunnelNetwork) {
		t.Fatal("without Tunnel the old shape (traefik-public) must be kept")
	}
}

// The clean-up removes every header a client could write a host, a path or an address into, fixes the port, and leaves
// alone the three the readers need: X-Forwarded-For (read from the right), X-Real-Ip (traefik's peer) and
// CF-Connecting-IP (read only when the hop is the tunnel).
func TestRenderForwardedHeaders_RemovesClientWritableHeaders(t *testing.T) {
	var doc map[string]any
	if err := yaml.Unmarshal([]byte(RenderForwardedHeaders()), &doc); err != nil {
		t.Fatalf("not YAML: %v", err)
	}
	h := doc["http"].(map[string]any)["middlewares"].(map[string]any)[ForwardedMiddleware].(map[string]any)["headers"].(map[string]any)["customRequestHeaders"].(map[string]any)
	for _, name := range []string{"X-Forwarded-Host", "X-Forwarded-Uri", "X-Forwarded-Method", "X-Forwarded-Prefix",
		"X-Forwarded-Tls-Client-Cert", "X-Forwarded-Tls-Client-Cert-Info", "Forwarded", "True-Client-Ip", "X-Client-Ip"} {
		if v, ok := h[name]; !ok || v != "" {
			t.Errorf("%s must be removed (empty value), got %v present=%v", name, v, ok)
		}
	}
	if h["X-Forwarded-Port"] != "443" {
		t.Errorf("X-Forwarded-Port must be fixed to 443, got %v", h["X-Forwarded-Port"])
	}
	for _, keep := range []string{"X-Forwarded-For", "X-Real-Ip", "CF-Connecting-IP", "Cf-Connecting-Ip", "X-Forwarded-Proto"} {
		if _, ok := h[keep]; ok {
			t.Errorf("%s must NOT be touched", keep)
		}
	}
}