import type { Currency } from './shared';
import { useEffect, useState } from 'react';
import { Loader2, Send } from 'lucide-react';
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from '@/components/ui/dialog';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';
import { Textarea } from '@/components/ui/textarea';
import { useDocumentAction, useSummary } from './useInvoiceShelfData';

// The one dialog in /invoices that causes something irreversible to leave the building: `send` hands the
// document to InvoiceShelf's mailer, which posts it to the customer. There is no unsend.
//
// So it is deliberately not a menu item that fires on click. The recipient is shown, editable, and
// pre-filled from the customer record rather than assumed; the button says who it is emailing; and nothing
// else in this app calls the send action. Everything that *looks* like sending but isn't — "mark as sent",
// which only moves the status — goes through a plain confirm instead, and says so.

export type SendTarget = {
  /** Sidecar resource slug: invoices | estimates | payments. */
  resource: string;
  id: number;
  /** Shown in the title, e.g. "000145". */
  number: string;
  customerName: string;
  customerEmail: string | null;
  /** Whether this is a first send or a resend, purely for wording. */
  resend?: boolean;
};

const DEFAULT_BODY = [
  '<p>Hi {CUSTOMER_NAME},</p>',
  '<p>Please find the attached document.</p>',
  '<p>Thanks,<br/>{COMPANY_NAME}</p>',
].join('\n');

const KIND_LABEL: Record<string, string> = {
  invoices: 'invoice',
  estimates: 'estimate',
  payments: 'payment receipt',
};

export const SendDocumentDialog = ({
  target,
  currency: _currency,
  onClose,
}: {
  target: SendTarget | null;
  currency?: Currency | null;
  onClose: () => void;
}) => {
  const { company, summary } = useSummary();
  const action = useDocumentAction(target?.resource ?? 'invoices');

  const kind = KIND_LABEL[target?.resource ?? ''] ?? 'document';

  const [to, setTo] = useState('');
  const [from, setFrom] = useState('');
  const [subject, setSubject] = useState('');
  const [body, setBody] = useState('');

  // Re-seed whenever a different document is opened. Keyed on id so reopening the same one keeps nothing
  // stale from a previous edit of another document's mail.
  useEffect(() => {
    if (!target) return;
    setTo(target.customerEmail ?? '');
    setFrom(summary?.me?.email ?? '');
    setSubject(`${company?.name ?? 'Invoice'} — ${kind} ${target.number}`);
    setBody(
      DEFAULT_BODY.replace('{CUSTOMER_NAME}', target.customerName || 'there').replace(
        '{COMPANY_NAME}',
        company?.name ?? '',
      ),
    );
  }, [target?.id, target?.resource, company?.name, summary?.me?.email, kind, target]);

  if (!target) return null;

  const missingRecipient = !to.trim();

  const submit = (ev?: React.FormEvent) => {
    ev?.preventDefault();
    action.mutate({ id: target.id, action: 'send', payload: { subject, body, from, to } }, { onSuccess: onClose });
  };

  return (
    <Dialog open onOpenChange={(open) => !open && onClose()}>
      <DialogContent className="sm:max-w-lg">
        {/* `contents` keeps the form invisible to DialogContent's grid layout — it still owns the gap between
            header, body and footer, the form just carries Enter-to-submit across all three. */}
        <form onSubmit={submit} className="contents">
          <DialogHeader>
            <DialogTitle>
              {target.resend ? 'Resend' : 'Send'} {kind} {target.number}
            </DialogTitle>
            <DialogDescription>
              This emails {target.customerName} through InvoiceShelf. It cannot be undone.
            </DialogDescription>
          </DialogHeader>

          <div className="space-y-3">
            <div className="grid grid-cols-2 gap-3">
              <div className="space-y-1">
                <Label className="text-xs">To</Label>
                <Input value={to} onChange={(e) => setTo(e.target.value)} className="h-8 text-xs" type="email" />
              </div>
              <div className="space-y-1">
                <Label className="text-xs">From</Label>
                <Input value={from} onChange={(e) => setFrom(e.target.value)} className="h-8 text-xs" type="email" />
              </div>
            </div>
            <div className="space-y-1">
              <Label className="text-xs">Subject</Label>
              <Input value={subject} onChange={(e) => setSubject(e.target.value)} className="h-8 text-xs" />
            </div>
            <div className="space-y-1">
              <Label className="text-xs">Message</Label>
              <Textarea value={body} onChange={(e) => setBody(e.target.value)} rows={7} className="text-xs" />
              <p className="text-[10px] text-muted-foreground">
                HTML. InvoiceShelf attaches the PDF itself — do not link it here.
              </p>
            </div>
            {missingRecipient && (
              <p className="text-[10px] text-warning">This customer has no email address on file. Enter one to send.</p>
            )}
          </div>

          <DialogFooter>
            <Button variant="ghost" size="sm" type="button" onClick={onClose} disabled={action.isPending}>
              Cancel
            </Button>
            <Button type="submit" size="sm" disabled={action.isPending || missingRecipient}>
              {action.isPending ? (
                <Loader2 className="mr-1.5 h-3.5 w-3.5 animate-spin" />
              ) : (
                <Send className="mr-1.5 h-3.5 w-3.5" />
              )}
              Send to {to || '—'}
            </Button>
          </DialogFooter>
        </form>
      </DialogContent>
    </Dialog>
  );
};