import { useState, useEffect } from "react";
import { Modal, Button, Form, Table, Alert } from "react-bootstrap";
import { updateGroupFees, OrderGroup, OrderGroupMember } from "../../../../types";
import { computeFeeShare, computeMemberTotal, countActiveMembers, isActiveMember } from "../../utils/groupFees";

type Props = {
    isOpen: boolean;
    onClose: () => void;
    group: OrderGroup;
    onSaved: (data: any) => void;
};

function parseHal(s: string): number {
    const n = parseFloat(s.replace(',', '.'));
    return isNaN(n) || n < 0 ? 0 : Math.round(n * 100);
}

function parsePercent(s: string): number {
    const n = parseFloat(s.replace(',', '.'));
    return isNaN(n) || n < 0 ? 0 : Math.round(n);
}

export default function EditGroupFeesModal({ isOpen, onClose, group, onSaved }: Readonly<Props>) {
    const [fees, setFees] = useState('');
    const [shipping, setShipping] = useState('');
    const [tip, setTip] = useState('');
    const [discountType, setDiscountType] = useState<'percent' | 'fixed'>('percent');
    const [discountValue, setDiscountValue] = useState('');
    const [error, setError] = useState<string | null>(null);
    const [loading, setLoading] = useState(false);

    useEffect(() => {
        if (!isOpen) return;
        setFees(group.fees ? String(group.fees / 100) : '');
        setShipping(group.shipping ? String(group.shipping / 100) : '');
        setTip(group.tip ? String(group.tip / 100) : '');
        setDiscountType((group.discountType as 'percent' | 'fixed') ?? 'percent');
        setDiscountValue(group.discountValue
            ? ((group.discountType as string) === 'fixed' ? String(group.discountValue / 100) : String(group.discountValue))
            : '');
        setError(null);
    }, [isOpen, group]);

    const memberEntries = Object.entries(group.members) as [string, OrderGroupMember][];
    // Poplatky se dělí jen mezi aktivní strávníky (kdo si reálně něco objednal).
    const activeCount = countActiveMembers(group.members);

    const feesNum = parseHal(fees);
    const shippingNum = parseHal(shipping);
    const tipNum = parseHal(tip);
    const discountNum = discountType === 'percent' ? parsePercent(discountValue) : parseHal(discountValue);
    const totalFees = feesNum + shippingNum + tipNum;
    const feeShare = computeFeeShare(totalFees, activeCount);
    const feeParams = { totalFees, discountType, discountValue: discountNum };

    const handleSave = async () => {
        setError(null);
        setLoading(true);
        try {
            const res = await updateGroupFees({
                body: {
                    id: group.id,
                    fees: feesNum,
                    shipping: shippingNum,
                    tip: tipNum,
                    discountType: discountNum > 0 ? discountType : undefined,
                    discountValue: discountNum > 0 ? discountNum : undefined,
                }
            });
            if (res.error) {
                setError((res.error as any).error || 'Nastala chyba');
            } else {
                onSaved(res.data);
                onClose();
            }
        } catch (e: any) {
            setError(e.message || 'Nastala chyba');
        } finally {
            setLoading(false);
        }
    };

    return (
        <Modal show={isOpen} onHide={onClose} size="lg">
            <Modal.Header closeButton>
                <Modal.Title><h2>Poplatky skupiny — {group.name}</h2></Modal.Title>
            </Modal.Header>
            <Modal.Body>
                {error && (
                    <Alert variant="danger" onClose={() => setError(null)} dismissible>{error}</Alert>
                )}

                <div className="d-flex gap-3 flex-wrap mb-3">
                    <Form.Group>
                        <Form.Label>Poplatky (Kč)</Form.Label>
                        <Form.Control
                            type="number" min={0} step={0.01}
                            value={fees} onChange={e => setFees(e.target.value)}
                            placeholder="0" style={{ width: 110 }}
                            onKeyDown={e => e.stopPropagation()}
                        />
                    </Form.Group>
                    <Form.Group>
                        <Form.Label>Doprava (Kč)</Form.Label>
                        <Form.Control
                            type="number" min={0} step={0.01}
                            value={shipping} onChange={e => setShipping(e.target.value)}
                            placeholder="0" style={{ width: 110 }}
                            onKeyDown={e => e.stopPropagation()}
                        />
                    </Form.Group>
                    <Form.Group>
                        <Form.Label>Spropitné (Kč)</Form.Label>
                        <Form.Control
                            type="number" min={0} step={0.01}
                            value={tip} onChange={e => setTip(e.target.value)}
                            placeholder="0" style={{ width: 110 }}
                            onKeyDown={e => e.stopPropagation()}
                        />
                    </Form.Group>
                </div>

                <div className="d-flex gap-3 align-items-end flex-wrap mb-3">
                    <Form.Group>
                        <Form.Label>Sleva</Form.Label>
                        <div className="d-flex gap-2 align-items-center">
                            <Form.Select
                                value={discountType}
                                onChange={e => setDiscountType(e.target.value as 'percent' | 'fixed')}
                                style={{ width: 160 }}
                            >
                                <option value="percent">Procentuální (%)</option>
                                <option value="fixed">Pevná částka (Kč)</option>
                            </Form.Select>
                            <Form.Control
                                type="number" min={0} step={discountType === 'percent' ? 1 : 0.01}
                                value={discountValue} onChange={e => setDiscountValue(e.target.value)}
                                placeholder="0" style={{ width: 100 }}
                                onKeyDown={e => e.stopPropagation()}
                            />
                            <span className="text-muted">{discountType === 'percent' ? '%' : 'Kč'}</span>
                        </div>
                    </Form.Group>
                </div>

                <hr />
                <h6>Náhled celkových částek ({activeCount} {activeCount === 1 ? 'strávník' : 'strávníků'} s objednávkou, {feeShare > 0 ? `poplatek ${feeShare / 100} Kč/os.` : 'bez poplatku'})</h6>
                <Table size="sm" bordered>
                    <thead>
                        <tr>
                            <th>Člen</th>
                            <th className="text-end">Základ</th>
                            <th className="text-end">Příplatek</th>
                            <th className="text-end">Poplatek</th>
                            <th className="text-end">Sleva</th>
                            <th className="text-end fw-bold">Celkem</th>
                        </tr>
                    </thead>
                    <tbody>
                        {memberEntries.map(([login, member]) => {
                            const base = member.amount ?? 0;
                            const surcharge = member.surchargeAmount ?? 0;
                            const active = isActiveMember(member);
                            const total = computeMemberTotal(member, feeParams, feeShare, activeCount);
                            // Sleva i poplatek se týkají jen aktivních strávníků.
                            const discount = active && discountNum > 0
                                ? (discountType === 'percent'
                                    ? Math.round((base + surcharge) * discountNum / 100)
                                    : Math.round(discountNum / activeCount))
                                : 0;
                            return (
                                <tr key={login} className={active ? '' : 'text-muted'}>
                                    <td><strong>{login}</strong>{!active && <small className="ms-1">(jen objednává)</small>}</td>
                                    <td className="text-end">{base > 0 ? `${base / 100} Kč` : '—'}</td>
                                    <td className="text-end">{surcharge > 0 ? `${surcharge / 100} Kč` : '—'}</td>
                                    <td className="text-end">{active && feeShare > 0 ? `${feeShare / 100} Kč` : '—'}</td>
                                    <td className="text-end text-danger">{discount > 0 ? `-${discount / 100} Kč` : '—'}</td>
                                    <td className="text-end fw-bold">{total > 0 ? `${total / 100} Kč` : '—'}</td>
                                </tr>
                            );
                        })}
                    </tbody>
                </Table>
            </Modal.Body>
            <Modal.Footer>
                <Button variant="secondary" onClick={onClose} disabled={loading}>Storno</Button>
                <Button variant="primary" onClick={handleSave} disabled={loading}>
                    {loading ? 'Ukládám...' : 'Uložit'}
                </Button>
            </Modal.Footer>
        </Modal>
    );
}