package mailops

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"testing"
	"time"

	"gitea.lab.audasmedia.com.au/sam/email_agent/internal/config"
	"gitea.lab.audasmedia.com.au/sam/email_agent/internal/store"
)

type fakeConn struct {
	selected    string
	uidValidity uint32
	created     []string
	moves       []string
	stores      []string
	searched    []string
	searchUIDs  []uint32
	searchErr   error
	loggedOut   bool
}

func (f *fakeConn) Login(string, string) error { return nil }
func (f *fakeConn) Select(mailbox string) (uint32, error) {
	f.selected = mailbox
	return f.uidValidity, nil
}
func (f *fakeConn) CreateMailbox(name string) error {
	f.created = append(f.created, name)
	return nil
}
func (f *fakeConn) Move(uid uint32, dest string) error {
	f.moves = append(f.moves, fmt.Sprintf("%d->%s", uid, dest))
	return nil
}
func (f *fakeConn) StoreFlags(uid uint32, op, flag string) error {
	f.stores = append(f.stores, fmt.Sprintf("%d %s%s", uid, op, flag))
	return nil
}
func (f *fakeConn) SearchGmailID(id string) ([]uint32, error) {
	f.searched = append(f.searched, id)
	return f.searchUIDs, f.searchErr
}
func (f *fakeConn) Logout() error { f.loggedOut = true; return nil }

func configured() *config.Config {
	return &config.Config{
		Env:              "test",
		IMAPHost:         config.DefaultIMAPHost,
		IMAPPort:         config.DefaultIMAPPort,
		GmailUser:        "user@example.test",
		GmailAppPassword: "app-password",
	}
}

func newFakeClient(fc *fakeConn) *Client {
	c := New(configured(), slog.New(slog.DiscardHandler))
	c.dial = func(context.Context, string, int, time.Duration) (Conn, error) { return fc, nil }
	return c
}

func TestMailboxForFolder(t *testing.T) {
	cases := []struct {
		folder string
		addr   string
		want   string
	}{
		{store.FolderInbox, "", "INBOX"},
		{store.FolderDelete, "", "Delete"},
		{store.FolderSaved, "", "Saved"},
		{store.FolderReplied, "Hello@Where-Woof.com", "Replied-to/hello@where-woof.com"},
		{store.FolderReplied, "", "Replied-to/unknown"},
		{"nonsense", "", "INBOX"},
	}
	for _, tc := range cases {
		if got := MailboxForFolder(tc.folder, tc.addr); got != tc.want {
			t.Errorf("MailboxForFolder(%q, %q) = %q, want %q", tc.folder, tc.addr, got, tc.want)
		}
	}
}

func TestSanitizeLabelAddress(t *testing.T) {
	if got := SanitizeLabelAddress(" <Sam+news@Example.com> "); got != "sam+news@example.com" {
		t.Errorf("SanitizeLabelAddress() = %q", got)
	}
	if got := SanitizeLabelAddress(`weird"name@x`); got != "weird_name@x" {
		t.Errorf("SanitizeLabelAddress() = %q", got)
	}
}

func TestMoveDeleteCreatesLabelAndUsesGmailID(t *testing.T) {
	fc := &fakeConn{uidValidity: 7, searchUIDs: []uint32{42}}
	c := newFakeClient(fc)

	label, err := c.Move(context.Background(), store.Message{
		ID: 1, GmailID: "1234000000000000000", Mailbox: "INBOX",
	}, store.FolderDelete)
	if err != nil {
		t.Fatalf("Move() error = %v", err)
	}
	if label != "Delete" {
		t.Errorf("label = %q, want Delete", label)
	}
	if len(fc.created) != 1 || fc.created[0] != "Delete" {
		t.Errorf("created = %v, want [Delete]", fc.created)
	}
	if fc.selected != "INBOX" {
		t.Errorf("selected = %q, want INBOX", fc.selected)
	}
	if len(fc.moves) != 1 || fc.moves[0] != "42->Delete" {
		t.Errorf("moves = %v, want [42->Delete]", fc.moves)
	}
	if len(fc.searched) != 1 || fc.searched[0] != "1234000000000000000" {
		t.Errorf("searched = %v", fc.searched)
	}
	if !fc.loggedOut {
		t.Error("connection was not logged out")
	}
}

func TestMoveRestoreDoesNotCreateInbox(t *testing.T) {
	fc := &fakeConn{uidValidity: 7, searchUIDs: []uint32{9}}
	c := newFakeClient(fc)

	label, err := c.Move(context.Background(), store.Message{
		ID: 2, GmailID: "555", Mailbox: "Delete",
	}, store.FolderInbox)
	if err != nil {
		t.Fatalf("Move() error = %v", err)
	}
	if label != "INBOX" {
		t.Errorf("label = %q, want INBOX", label)
	}
	if len(fc.created) != 0 {
		t.Errorf("created = %v, want none for INBOX", fc.created)
	}
	if fc.selected != "Delete" {
		t.Errorf("selected = %q, want Delete", fc.selected)
	}
	if len(fc.moves) != 1 || fc.moves[0] != "9->INBOX" {
		t.Errorf("moves = %v", fc.moves)
	}
}

func TestMoveNoopWhenAlreadyInFolder(t *testing.T) {
	fc := &fakeConn{}
	c := newFakeClient(fc)
	if _, err := c.Move(context.Background(), store.Message{ID: 3, GmailID: "1", Mailbox: "Saved"}, store.FolderSaved); err != nil {
		t.Fatalf("Move() error = %v", err)
	}
	if len(fc.moves) != 0 || len(fc.searched) != 0 {
		t.Errorf("no-op move did work: moves=%v searched=%v", fc.moves, fc.searched)
	}
}

func TestMoveRejectsNonGmailID(t *testing.T) {
	c := newFakeClient(&fakeConn{})
	_, err := c.Move(context.Background(), store.Message{ID: 4, GmailID: "uid:7:9", Mailbox: "INBOX"}, store.FolderDelete)
	if err == nil {
		t.Fatal("Move() error = nil, want failure for a uid: fallback id")
	}
}

func TestMoveNotConfigured(t *testing.T) {
	c := New(&config.Config{Env: "test", IMAPHost: config.DefaultIMAPHost, IMAPPort: config.DefaultIMAPPort}, nil)
	_, err := c.Move(context.Background(), store.Message{ID: 5, GmailID: "1", Mailbox: "INBOX"}, store.FolderDelete)
	if !errors.Is(err, ErrNotConfigured) {
		t.Fatalf("Move() error = %v, want ErrNotConfigured", err)
	}
}

func TestMarkMapsFlags(t *testing.T) {
	cases := []struct {
		mark string
		want string
	}{
		{"read", "3 +\\Seen"},
		{"unread", "3 -\\Seen"},
		{"star", "3 +\\Flagged"},
		{"unstar", "3 -\\Flagged"},
	}
	for _, tc := range cases {
		fc := &fakeConn{uidValidity: 1, searchUIDs: []uint32{3}}
		c := newFakeClient(fc)
		if err := c.Mark(context.Background(), store.Message{ID: 6, GmailID: "777"}, tc.mark); err != nil {
			t.Fatalf("Mark(%q) error = %v", tc.mark, err)
		}
		if len(fc.stores) != 1 || fc.stores[0] != tc.want {
			t.Errorf("Mark(%q) stores = %v, want %q", tc.mark, fc.stores, tc.want)
		}
	}
}

func TestMarkUnknown(t *testing.T) {
	c := newFakeClient(&fakeConn{})
	if err := c.Mark(context.Background(), store.Message{ID: 7, GmailID: "1"}, "bogus"); err == nil {
		t.Fatal("Mark(bogus) error = nil, want failure")
	}
}