import React, {useState} from 'react';
import {ArrowRightLeft, CheckCircle, AlertTriangle, FolderOpen, Loader2} from 'lucide-react';
import Modal from '@/components/ui/Modal';
import Button from '@/components/ui/Button';
import {useTranslations} from '@/lib/i18n';
import * as tauri from '@/lib/tauri';

interface MigrationModalProps {
    onClose: () => void;
    onSuccess: () => void;
}

type MigrationStep = 'intro' | 'select' | 'importing' | 'success' | 'error';

export default function MigrationModal({onClose, onSuccess}: MigrationModalProps) {
    const t = useTranslations();
    const [step, setStep] = useState<MigrationStep>('intro');
    const [filePath, setFilePath] = useState<string>('');
    const [errorMsg, setErrorMsg] = useState<string>('');
    const [migratedUserId, setMigratedUserId] = useState<string>('');

    async function handleCheck(): Promise<void> {
        if (!filePath.trim()) return;

        try {
            const result: tauri.MigrationCheckResult = await tauri.checkElectronMigration(filePath.trim());
            if (!result.found) {
                setErrorMsg(t('migration.fileNotFound'));
                setStep('error');
                return;
            }
            if (!result.hasDb) {
                setErrorMsg(t('migration.dbNotFound'));
                setStep('error');
                return;
            }
            await handleImport();
        } catch (e: unknown) {
            setErrorMsg(e instanceof Error ? e.message : String(e));
            setStep('error');
        }
    }

    async function handleImport(): Promise<void> {
        setStep('importing');
        try {
            const result: tauri.MigrationResult = await tauri.importFromElectron(filePath.trim());
            if (result.success) {
                setMigratedUserId(result.userId || '');
                setStep('success');
            } else {
                setErrorMsg(result.error || t('migration.importFailed'));
                setStep('error');
            }
        } catch (e: unknown) {
            setErrorMsg(e instanceof Error ? e.message : String(e));
            setStep('error');
        }
    }

    function handleSuccessClose(): void {
        localStorage.setItem('electron_migration_done', 'true');
        onSuccess();
    }

    function handleDismiss(): void {
        localStorage.setItem('electron_migration_dismissed', 'true');
        onClose();
    }

    return (
        <Modal
            title={t('migration.title')}
            icon={ArrowRightLeft}
            size="md"
            onClose={onClose}
        >
            {step === 'intro' && (
                <div className="space-y-4">
                    <p className="text-muted leading-relaxed">{t('migration.introText')}</p>
                    <div className="bg-tertiary rounded-xl p-4 space-y-2">
                        <p className="text-sm font-semibold text-text-primary">{t('migration.steps')}</p>
                        <ol className="list-decimal list-inside text-sm text-muted space-y-1">
                            <li>{t('migration.step1')}</li>
                            <li>{t('migration.step2')}</li>
                            <li>{t('migration.step3')}</li>
                        </ol>
                    </div>
                    <div className="flex justify-end gap-3 pt-2">
                        <Button variant="secondary" onClick={handleDismiss}>
                            {t('migration.later')}
                        </Button>
                        <Button variant="primary" icon={FolderOpen} onClick={function (): void {
                            setStep('select');
                        }}>
                            {t('migration.haveFile')}
                        </Button>
                    </div>
                </div>
            )}

            {step === 'select' && (
                <div className="space-y-4">
                    <p className="text-muted text-sm">{t('migration.selectText')}</p>
                    <div className="space-y-2">
                        <label className="text-sm font-medium text-text-primary">
                            {t('migration.filePath')}
                        </label>
                        <input
                            type="text"
                            value={filePath}
                            onChange={function (e: React.ChangeEvent<HTMLInputElement>): void {
                                setFilePath(e.target.value);
                            }}
                            placeholder="/Users/.../Desktop/eritors-migration.json"
                            className="w-full px-4 py-2.5 rounded-xl bg-tertiary border border-secondary text-text-primary text-sm placeholder:text-muted/50 focus:outline-none focus:border-primary"
                        />
                    </div>
                    <div className="flex justify-end gap-3 pt-2">
                        <Button variant="secondary" onClick={function (): void {
                            setStep('intro');
                        }}>
                            {t('migration.back')}
                        </Button>
                        <Button variant="primary" onClick={handleCheck} disabled={!filePath.trim()}>
                            {t('migration.import')}
                        </Button>
                    </div>
                </div>
            )}

            {step === 'importing' && (
                <div className="flex flex-col items-center py-8 space-y-4">
                    <Loader2 className="w-10 h-10 text-primary animate-spin" strokeWidth={1.75}/>
                    <p className="text-muted">{t('migration.importing')}</p>
                </div>
            )}

            {step === 'success' && (
                <div className="space-y-4">
                    <div className="flex flex-col items-center py-6 space-y-3">
                        <CheckCircle className="w-12 h-12 text-success" strokeWidth={1.75}/>
                        <p className="text-text-primary font-semibold text-lg">{t('migration.successTitle')}</p>
                        <p className="text-muted text-sm text-center">{t('migration.successText')}</p>
                    </div>
                    <div className="flex justify-end pt-2">
                        <Button variant="primary" onClick={handleSuccessClose}>
                            {t('migration.done')}
                        </Button>
                    </div>
                </div>
            )}

            {step === 'error' && (
                <div className="space-y-4">
                    <div className="flex flex-col items-center py-6 space-y-3">
                        <AlertTriangle className="w-12 h-12 text-error" strokeWidth={1.75}/>
                        <p className="text-text-primary font-semibold">{t('migration.errorTitle')}</p>
                        <p className="text-muted text-sm text-center">{errorMsg}</p>
                    </div>
                    <div className="flex justify-end gap-3 pt-2">
                        <Button variant="secondary" onClick={onClose}>
                            {t('migration.close')}
                        </Button>
                        <Button variant="primary" onClick={function (): void {
                            setStep('select');
                            setErrorMsg('');
                        }}>
                            {t('migration.retry')}
                        </Button>
                    </div>
                </div>
            )}
        </Modal>
    );
}