"use client"

import { useActionState, useEffect, useState } from "react";
import { Field, FieldGroup, FieldLabel } from "@/components/ui/field";
import { Input } from "@/components/ui/input";
import { Button } from "@/components/ui/button";
import { saveStammdaten, StammdatenState } from "@/modules/shared/actions/stammdaten";
import {
    Building2,
    CreditCard,
    FileText,
    MapPin,
    User,
    type LucideIcon,
} from "lucide-react";
import { LEGAL_FORMS } from "@/modules/shared/data/stammdaten-data";

type Client = {
    company_name: string;
    legal_form: string;
    industry: string | null;
    vat_id: string | null;
    tax_number: string | null;
    commercial_register_number: string | null;
    street: string;
    postal_code: string;
    city: string;
    country: string;
    billing_street: string | null;
    billing_postal_code: string | null;
    billing_city: string | null;
    billing_country: string | null;
    contact_name: string;
    contact_position: string | null;
    contact_email: string;
    contact_phone: string | null;
} | null;

type PaymentDetails = {
    payment_method: "invoice" | "sepa_debit" | "card";
    account_holder: string | null;
    iban: string | null;
    bic: string | null;
} | null;

const selectClassName =
    "flex h-10 w-full rounded-md border border-input bg-background px-3 text-body outline-none transition-colors placeholder:text-muted-foreground disabled:cursor-not-allowed disabled:opacity-50";

function FormSection({
    icon: Icon,
    title,
    children,
}: {
    icon: LucideIcon;
    title: string;
    children: React.ReactNode;
}) {
    return (
        <div className="rounded-lg border border-border bg-surface/50 p-4 sm:p-5">
            <div className="mb-4 flex items-center gap-2 sm:mb-5">
                <Icon className="size-4.5 text-muted-foreground" />
                <h2 className="text-base font-semibold">{title}</h2>
            </div>
            <FieldGroup className="@container grid grid-cols-1 gap-4 @md:grid-cols-2">
                {children}
            </FieldGroup>
        </div>
    );
}

function TextField({
    name,
    label,
    defaultValue,
    type = "text",
    required,
    disabled,
}: {
    name: string;
    label: string;
    defaultValue?: string | null;
    type?: string;
    required?: boolean;
    disabled?: boolean;
}) {
    return (
        <Field>
            <FieldLabel htmlFor={name}>
                {label} {required && <span className="text-destructive">*</span>}
            </FieldLabel>
            <Input
                id={name}
                name={name}
                type={type}
                defaultValue={defaultValue ?? ""}
                required={required}
                disabled={disabled}
                className="focus-visible:ring-0"
            />
        </Field>
    );
}

function SelectField({
    name,
    label,
    value,
    defaultValue,
    onChange,
    options,
    required,
    disabled,
}: {
    name: string;
    label: string;
    value?: string;
    defaultValue?: string;
    onChange?: (value: string) => void;
    options: { value: string; label: string }[];
    required?: boolean;
    disabled?: boolean;
}) {
    return (
        <Field>
            <FieldLabel htmlFor={name}>
                {label} {required && <span className="text-destructive">*</span>}
            </FieldLabel>
            <select
                id={name}
                name={name}
                value={value}
                defaultValue={defaultValue}
                onChange={onChange ? (event) => onChange(event.target.value) : undefined}
                disabled={disabled}
                required={required}
                className={selectClassName}
            >
                {options.map((option) => (
                    <option key={option.value} value={option.value}>
                        {option.label}
                    </option>
                ))}
            </select>
        </Field>
    );
}

const StammdatenForm = ({
    profileId,
    client,
    paymentDetails,
    isEditing,
    onDone,
}: {
    profileId: string;
    client: Client;
    paymentDetails: PaymentDetails;
    isEditing: boolean;
    onDone: () => void;
}) => {
    const [state, formAction, pending] = useActionState<StammdatenState, FormData>(
        saveStammdaten,
        undefined
    );
    const [paymentMethod, setPaymentMethod] = useState(paymentDetails?.payment_method ?? "invoice");
    const [hasDifferentBillingAddress, setHasDifferentBillingAddress] = useState(
        Boolean(client?.billing_street)
    );

    useEffect(() => {
        if (state && "success" in state && state.success) {
            onDone();
        }
    }, [state, onDone]);

    const disabled = !isEditing || pending;

    return (
        <form action={formAction} className="flex flex-col gap-6">
            <input type="hidden" name="profileId" value={profileId} />

            <fieldset disabled={disabled} className="flex flex-col gap-6">
                <FormSection icon={Building2} title="Firma">
                    <TextField name="companyName" label="Firmenname" defaultValue={client?.company_name} required />
                    <SelectField
                        name="legalForm"
                        label="Rechtsform"
                        defaultValue={client?.legal_form ?? LEGAL_FORMS[0]}
                        disabled={disabled}
                        required
                        options={LEGAL_FORMS.map((form) => ({ value: form, label: form }))}
                    />
                    <TextField name="industry" label="Branche" defaultValue={client?.industry} />
                    <TextField name="vatId" label="USt-IdNr" defaultValue={client?.vat_id} />
                    <TextField name="taxNumber" label="Steuernummer" defaultValue={client?.tax_number} />
                    <TextField
                        name="commercialRegisterNumber"
                        label="Handelsregisternummer"
                        defaultValue={client?.commercial_register_number}
                    />
                </FormSection>

                <FormSection icon={MapPin} title="Firmenadresse">
                    <TextField name="street" label="Straße & Hausnummer" defaultValue={client?.street} required />
                    <TextField name="postalCode" label="PLZ" defaultValue={client?.postal_code} required />
                    <TextField name="city" label="Stadt" defaultValue={client?.city} required />
                    <SelectField
                        name="country"
                        label="Land"
                        defaultValue={client?.country ?? "DE"}
                        disabled={disabled}
                        options={[
                            { value: "DE", label: "Deutschland" },
                            { value: "AT", label: "Österreich" },
                            { value: "CH", label: "Schweiz" },
                        ]}
                    />
                </FormSection>

                <div className="rounded-lg border border-border bg-surface/50 p-4 sm:p-5">
                    <label className="mb-4 flex items-center gap-2 has-disabled:opacity-50 sm:mb-5">
                        <input
                            type="checkbox"
                            checked={hasDifferentBillingAddress}
                            onChange={(event) => setHasDifferentBillingAddress(event.target.checked)}
                            disabled={disabled}
                            className="size-4 rounded border-input accent-primary"
                        />
                        <FileText className="size-4.5 text-muted-foreground" />
                        <span className="text-base font-semibold">Abweichende Rechnungsadresse</span>
                    </label>
                    {hasDifferentBillingAddress && (
                        <FieldGroup className="@container grid grid-cols-1 gap-4 @md:grid-cols-2">
                            <TextField
                                name="billingStreet"
                                label="Straße & Hausnummer"
                                defaultValue={client?.billing_street}
                                required
                            />
                            <TextField
                                name="billingPostalCode"
                                label="PLZ"
                                defaultValue={client?.billing_postal_code}
                                required
                            />
                            <TextField name="billingCity" label="Stadt" defaultValue={client?.billing_city} required />
                            <TextField
                                name="billingCountry"
                                label="Land"
                                defaultValue={client?.billing_country}
                                required
                            />
                        </FieldGroup>
                    )}
                </div>

                <FormSection icon={User} title="Ansprechpartner">
                    <TextField name="contactName" label="Name" defaultValue={client?.contact_name} required />
                    <TextField name="contactPosition" label="Position" defaultValue={client?.contact_position} />
                    <TextField name="contactEmail" label="Email" type="email" defaultValue={client?.contact_email} required />
                    <TextField name="contactPhone" label="Telefon" defaultValue={client?.contact_phone} />
                </FormSection>

                <FormSection icon={CreditCard} title="Zahlungsdaten">
                    <SelectField
                        name="paymentMethod"
                        label="Zahlungsart"
                        value={paymentMethod}
                        onChange={(value) => setPaymentMethod(value as typeof paymentMethod)}
                        disabled={disabled}
                        options={[
                            { value: "invoice", label: "Rechnung" },
                            { value: "sepa_debit", label: "SEPA-Lastschrift" },
                            { value: "card", label: "Kreditkarte" },
                        ]}
                    />
                    {paymentMethod === "sepa_debit" && (
                        <>
                            <TextField
                                name="accountHolder"
                                label="Kontoinhaber"
                                defaultValue={paymentDetails?.account_holder}
                                required
                            />
                            <TextField name="iban" label="IBAN" defaultValue={paymentDetails?.iban} required />
                            <TextField name="bic" label="BIC" defaultValue={paymentDetails?.bic} />
                        </>
                    )}
                </FormSection>
            </fieldset>

            {state && "error" in state && (
                <p className="text-sm text-destructive">{state.error}</p>
            )}

            {isEditing && (
                <div className="flex flex-col-reverse gap-2 sm:flex-row sm:justify-end">
                    <Button type="button" variant="outline" onClick={onDone} disabled={pending}>
                        Abbrechen
                    </Button>
                    <Button type="submit" disabled={pending}>
                        {pending ? "Wird gespeichert..." : "Speichern"}
                    </Button>
                </div>
            )}
        </form>
    );
};

export default StammdatenForm;