package server

import (
	"context"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"crypto/tls"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/pem"
	"io"
	"log/slog"
	"math/big"
	"net"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"jarl/internal/auth"
	"jarl/internal/certs"
	"jarl/internal/model"
)

// selfSigned writes a self-signed certificate for names into dir.
func selfSigned(t *testing.T, dir string, names ...string) (certFile, keyFile string) {
	t.Helper()
	key, _ := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	tmpl := &x509.Certificate{SerialNumber: big.NewInt(time.Now().UnixNano()), Subject: pkix.Name{CommonName: names[0]}, DNSNames: names,
		NotBefore: time.Now().Add(-time.Hour), NotAfter: time.Now().Add(30 * 24 * time.Hour), ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth}}
	der, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, &key.PublicKey, key)
	if err != nil {
		t.Fatal(err)
	}
	kd, _ := x509.MarshalPKCS8PrivateKey(key)
	certFile, keyFile = filepath.Join(dir, "cert.pem"), filepath.Join(dir, "key.pem")
	os.WriteFile(certFile, pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: der}), 0o600)
	os.WriteFile(keyFile, pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: kd}), 0o600)
	return
}

func withCerts(env *apiEnv) *certs.Manager {
	quiet := slog.New(slog.NewTextHandler(io.Discard, nil))
	m := certs.New(certs.Config{Dir: filepath.Join(env.t.TempDir(), "tls"), Directory: "https://acme.invalid/dir"}, env.st, env.srv.eng, quiet)
	env.srv.cfg.Certs = m
	return m
}

func TestCertificatesAPI(t *testing.T) {
	env := newAPIEnv(t)
	m := withCerts(env)
	certFile, keyFile := selfSigned(t, t.TempDir(), "jarl.example.com")

	// A user who isn't an administrator sees nothing.
	hash, _ := auth.HashPassword("pw-pw-pw-pw")
	u := &model.User{Username: "ops", PasswordHash: hash, Grants: []model.Grant{{Resource: "*", Access: "write"}}}
	env.st.CreateUser(context.Background(), u)
	tok, pid, sh := auth.NewToken()
	env.st.CreateToken(context.Background(), &model.Token{UserID: u.ID, Name: "t", PublicID: pid, SecretHash: sh})
	env.do("GET", "/certificates", tok, nil, 403)

	out := env.do("POST", "/certificates", env.token, map[string]any{"name": "own", "source": "file", "cert_file": certFile, "key_file": keyFile, "uses": []string{"web"}}, 201)
	c := out["certificate"].(map[string]any)
	if c["serving"] != true || c["status"].(map[string]any)["state"] != "ok" || c["domains"].([]any)[0] != "jarl.example.com" {
		t.Errorf("created: %v", c)
	}
	if _, has := c["key_pem"]; has {
		t.Error("the key left the server")
	}
	if m.WebCertificate() == nil {
		t.Error("not serving")
	}
	env.do("POST", "/certificates", env.token, map[string]any{"name": "own", "domains": []string{"a.example.com"}}, 409)
	env.do("POST", "/certificates", env.token, map[string]any{"name": "x", "domains": []string{"a.example.com"}, "uses": []string{"web"}}, 400)
	env.do("POST", "/certificates", env.token, map[string]any{"name": "x", "source": "file", "cert_file": "/nonexistent.pem", "key_file": keyFile}, 400)
	list := env.do("GET", "/certificates", env.token, nil, 200)
	if n := len(list["certificates"].([]any)); n != 1 || list["account"].(map[string]any)["directory"] != "https://acme.invalid/dir" {
		t.Errorf("list: %v", list)
	}
	env.do("PATCH", "/certificates/own", env.token, map[string]any{"uses": []string{"dns"}}, 200)
	if m.WebCertificate() != nil {
		t.Error("still serving after the web use was taken off")
	}
	got := env.do("GET", "/certificates/own", env.token, nil, 200)
	if files, ok := got["files"].(map[string]any); !ok || !strings.HasSuffix(files["key"].(string), "/own/privkey.pem") {
		t.Errorf("files: %v", got["files"])
	}
	env.do("POST", "/certificates/own/issue", env.token, map[string]any{}, 200)
	env.do("DELETE", "/certificates/own", env.token, nil, 200)
	env.do("GET", "/certificates/own", env.token, nil, 404)
}

func TestHTTPSAndPlainOnOnePort(t *testing.T) {
	env := newAPIEnv(t)
	certFile, keyFile := selfSigned(t, t.TempDir(), "jarl.example.com")
	s := env.srv
	cr, err := newCertReloader(certFile, keyFile, s.log)
	if err != nil {
		t.Fatal(err)
	}
	s.certs = cr
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	cfg := &tls.Config{GetCertificate: s.webCertificate, NextProtos: []string{"h2", "http/1.1"}}
	hs := &http.Server{Handler: s.requireHTTPS(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.TLS != nil {
			io.WriteString(w, "tls "+r.Proto)
		} else {
			io.WriteString(w, "plain")
		}
	}))}
	go hs.Serve(newSniffListener(ln, cfg))
	t.Cleanup(func() { hs.Close() })
	addr := ln.Addr().String()

	get := func(c *http.Client, url string) string {
		t.Helper()
		resp, err := c.Get(url)
		if err != nil {
			t.Fatal(err)
		}
		defer resp.Body.Close()
		b, _ := io.ReadAll(resp.Body)
		return string(b)
	}
	tlsClient := &http.Client{Transport: &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true}, ForceAttemptHTTP2: true}}
	if got := get(tlsClient, "https://"+addr+"/"); got != "tls HTTP/2.0" {
		t.Errorf("HTTPS: %q", got)
	}
	// Loopback may still use plain HTTP (tools on the server itself).
	if got := get(http.DefaultClient, "http://"+addr+"/"); got != "plain" {
		t.Errorf("plain from loopback: %q", got)
	}

	// From elsewhere: browsers are redirected, API calls refused.
	h := s.requireHTTPS(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { io.WriteString(w, "served") }))
	req := httptest.NewRequest("GET", "http://dns.example.com:8053/zones?x=1", nil)
	req.RemoteAddr = "192.0.2.10:5555"
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusPermanentRedirect || rec.Header().Get("Location") != "https://dns.example.com:8053/zones?x=1" {
		t.Errorf("GET from elsewhere: %d %s", rec.Code, rec.Header().Get("Location"))
	}
	req = httptest.NewRequest("POST", "http://dns.example.com:8053/api/v1/records", strings.NewReader("{}"))
	req.RemoteAddr = "192.0.2.10:5555"
	req.Header.Set("Authorization", "Bearer x")
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusBadRequest || !strings.Contains(rec.Body.String(), "https_required") || !strings.Contains(rec.Body.String(), "rotate the token") {
		t.Errorf("POST from elsewhere: %d %s", rec.Code, rec.Body.String())
	}
	// Without any certificate, plain HTTP is served as before.
	s.certs = nil
	rec = httptest.NewRecorder()
	req = httptest.NewRequest("GET", "http://dns.example.com:8053/", nil)
	req.RemoteAddr = "192.0.2.10:5555"
	h.ServeHTTP(rec, req)
	if rec.Body.String() != "served" {
		t.Errorf("no certificate: %d %s", rec.Code, rec.Body.String())
	}
}