package mailingress

import (
	"context"
	"crypto/tls"
	"github.com/emersion/go-imap/backend/memory"
	"github.com/emersion/go-imap/server"
	"github.com/example/notify-gateway/internal/gateway"
	"github.com/example/notify-gateway/internal/outbox"
	"github.com/example/notify-gateway/internal/testutil"
	"io"
	"log"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/example/notify-gateway/internal/config"
)

func TestIMAPCheckpointsAndDurableAcceptance(t *testing.T) {
	ctx := context.Background()
	serverTLS, clientTLS := testutil.TLSConfigs()
	listener, err := tls.Listen("tcp", "127.0.0.1:0", serverTLS)
	if err != nil {
		t.Fatal(err)
	}
	backend := memory.New()
	srv := server.New(backend)
	srv.ErrorLog = log.New(io.Discard, "", 0)
	done := make(chan struct{})
	go func() { defer close(done); srv.Serve(listener) }()
	defer func() { srv.Close(); <-done }()
	dir := t.TempDir()
	cfg, _ := config.Open(filepath.Join(dir, "config.json"))
	db, err := outbox.Open(filepath.Join(dir, "outbox.db"))
	if err != nil {
		t.Fatal(err)
	}
	defer db.Close()
	c := cfg.Get()
	c.Mappings = []config.Mapping{{ID: "mail", Enabled: true, Source: "mail", Target: "news", TextTemplate: "{{.Message}}"}}
	if err := cfg.Replace(c); err != nil {
		t.Fatal(err)
	}
	q := &gateway.Queue{Store: db, Dispatcher: gateway.New(cfg, nil)}
	p := &Poller{Config: cfg, Queue: q}
	m := config.MailIngress{ID: "mail", Address: listener.Addr().String(), Username: "username", Password: "password", Folder: "INBOX", Channel: "mail"}
	// Existing UID 6 is skipped on first setup; mailbox remains read-only.
	if err := p.poll(ctx, m, clientTLS); err != nil {
		t.Fatal(err)
	}
	rows, _ := db.List(ctx, 50, 0)
	if len(rows) != 0 {
		t.Fatal("old mail imported unexpectedly")
	}
	cpID := gateway.ScopedKey("imap", m.ID, m.Address, m.Username, m.Folder)
	old, _ := db.Checkpoint(ctx, cpID)
	user, _ := backend.Login(nil, "username", "password")
	mailbox, _ := user.GetMailbox("INBOX")
	appendMail := func(body string) {
		t.Helper()
		if err := mailbox.CreateMessage(nil, time.Now(), strings.NewReader("From: sender@example.org\r\nSubject: Test\r\nContent-Type: text/plain\r\n\r\n"+body)); err != nil {
			t.Fatal(err)
		}
	}
	appendMail("new mail")
	if err := p.poll(ctx, m, clientTLS); err != nil {
		t.Fatal(err)
	}
	rows, _ = db.List(ctx, 50, 0)
	if len(rows) != 1 {
		t.Fatalf("new mail jobs=%d", len(rows))
	}
	// Simulate a crash after receipt commit but before checkpoint persistence.
	if err := db.SetCheckpoint(ctx, cpID, old); err != nil {
		t.Fatal(err)
	}
	if err := p.poll(ctx, m, clientTLS); err != nil {
		t.Fatal(err)
	}
	rows, _ = db.List(ctx, 50, 0)
	if len(rows) != 1 {
		t.Fatal("duplicate IMAP delivery")
	}
	saved, _ := db.Checkpoint(ctx, cpID)
	c.Mappings[0].Enabled = false
	cfg.Replace(c)
	appendMail("pending routing")
	if err := p.poll(ctx, m, clientTLS); err == nil {
		t.Fatal("missing mapping accepted")
	}
	after, _ := db.Checkpoint(ctx, cpID)
	if after != saved {
		t.Fatal("checkpoint advanced past unaccepted mail")
	}
	c.Mappings[0].Enabled = true
	cfg.Replace(c)
	if err := p.poll(ctx, m, clientTLS); err != nil {
		t.Fatal(err)
	}
	rows, _ = db.List(ctx, 50, 0)
	if len(rows) != 2 {
		t.Fatal("mail was lost")
	}
	if err := p.Poll(ctx, m); err == nil {
		t.Fatal("untrusted IMAP certificate accepted")
	}
}

func TestMIMEFiltersAndLoopProtection(t *testing.T) {
	raw := "From: Sender <sender@example.org>\r\nTo: ops@example.org\r\nSubject: =?UTF-8?Q?Gr=C3=BC=C3=9Fe?=\r\nMIME-Version: 1.0\r\nContent-Type: multipart/mixed; boundary=test\r\n\r\n--test\r\nContent-Type: text/plain; charset=utf-8\r\nContent-Transfer-Encoding: base64\r\n\r\nSGFsbG8=\r\n--test\r\nContent-Type: application/octet-stream\r\nContent-Disposition: attachment; filename=test.txt\r\n\r\nnot forwarded\r\n--test--\r\n"
	cfg := config.MailIngress{Channel: "ops", From: []string{"sender@example.org"}, To: []string{"ops@example.org"}}
	msg, skip, err := Parse([]byte(raw), cfg)
	if err != nil || skip || msg.Title != "Grüße" || msg.Message != "Hallo" || msg.Source != "mail" {
		t.Fatalf("%+v %v %v", msg, skip, err)
	}
	if _, skip, err := Parse([]byte("X-Notify-Gateway: 1\r\n"+raw), cfg); err != nil || !skip {
		t.Fatalf("loop: %v %v", skip, err)
	}
	cfg.From = []string{"other@example.org"}
	if _, skip, err := Parse([]byte(raw), cfg); err != nil || !skip {
		t.Fatalf("sender filter: %v %v", skip, err)
	}
	if _, _, err := Parse([]byte(strings.Repeat("x", maxMailBytes+1)), cfg); err == nil {
		t.Fatal("oversize accepted")
	}
	if _, _, err := Parse([]byte("Content-Type: text/html\r\n\r\n<b>hello</b>"), config.MailIngress{}); err == nil {
		t.Fatal("HTML-only mail should require attention")
	}
}