import { useEffect, useState, useCallback } from 'react';
import {
  Table, Typography, Tag, Button, Modal, Select, message, Space, Radio,
} from 'antd';
import { CheckCircleOutlined } from '@ant-design/icons';
import type { ColumnsType } from 'antd/es/table';
import dayjs from 'dayjs';
import { freigabeApi, type FreigabeDocument, type FreigabeOption } from '../api/freigabe';
import { paperlessApi, type PaperlessDocType, type PaperlessCorrespondent } from '../api/paperless';

const { Title } = Typography;
const FREIGABE_FIELD_ID = 15;

export default function FreigabePage() {
  const [data, setData] = useState<FreigabeDocument[]>([]);
  const [total, setTotal] = useState(0);
  const [loading, setLoading] = useState(false);
  const [page, setPage] = useState(1);
  const [pageSize, setPageSize] = useState(25);
  const [nurNichtFreigegeben, setNurNichtFreigegeben] = useState(true);

  const [docTypes, setDocTypes] = useState<PaperlessDocType[]>([]);
  const [correspondents, setCorrespondents] = useState<PaperlessCorrespondent[]>([]);
  const [freigabeOptions, setFreigabeOptions] = useState<FreigabeOption[]>([]);

  const [selectedDoc, setSelectedDoc] = useState<FreigabeDocument | null>(null);
  const [modalOpen, setModalOpen] = useState(false);
  const [selectedValue, setSelectedValue] = useState<string | null>(null);
  const [saving, setSaving] = useState(false);

  useEffect(() => {
    Promise.all([
      paperlessApi.getDocumentTypes(),
      paperlessApi.getCorrespondents(),
      freigabeApi.getOptions(),
    ]).then(([dts, corrs, opts]) => {
      setDocTypes(dts);
      setCorrespondents(corrs);
      setFreigabeOptions(opts);
    });
  }, []);

  const fetchData = useCallback(async () => {
    setLoading(true);
    try {
      const result = await freigabeApi.getDocuments(page, pageSize, nurNichtFreigegeben);
      setData(result.results ?? []);
      setTotal(result.count ?? 0);
    } catch {
      message.error('Fehler beim Laden der Belege');
    } finally {
      setLoading(false);
    }
  }, [page, pageSize, nurNichtFreigegeben]);

  useEffect(() => {
    fetchData();
  }, [fetchData]);

  const getDocTypeName = (id: number | null) => {
    if (!id) return '—';
    return docTypes.find((d) => d.id === id)?.name ?? String(id);
  };

  const getCorrespondentName = (id: number | null) => {
    if (!id) return '—';
    return correspondents.find((c) => c.id === id)?.name ?? String(id);
  };

  const toCfString = (value: any): string | null => {
    if (value === null || value === undefined || value === '') return null;
    if (typeof value === 'object') return String(value?.id ?? value?.value ?? value?.label ?? '') || null;
    return String(value);
  };

  const getFreigabeValue = (doc: FreigabeDocument) => {
    const cf = doc.custom_fields?.find((f) => f.field === FREIGABE_FIELD_ID);
    const cfStr = toCfString(cf?.value);
    if (!cfStr) return <Tag color="warning">Nicht gesetzt</Tag>;
    const opt = freigabeOptions.find((o) => o.id === cfStr);
    return <Tag color="success">{opt?.label ?? cfStr}</Tag>;
  };

  const openModal = (doc: FreigabeDocument) => {
    const cf = doc.custom_fields?.find((f) => f.field === FREIGABE_FIELD_ID);
    setSelectedDoc(doc);
    setSelectedValue(toCfString(cf?.value));
    setModalOpen(true);
  };

  const handleFreigabe = async () => {
    if (!selectedDoc) return;
    setSaving(true);
    try {
      await freigabeApi.setFreigabe(selectedDoc.id, selectedValue);
      message.success('Freigabe gesetzt');
      setModalOpen(false);
      setSelectedDoc(null);
      fetchData();
    } catch {
      message.error('Fehler beim Speichern der Freigabe');
    } finally {
      setSaving(false);
    }
  };

  const columns: ColumnsType<FreigabeDocument> = [
    {
      title: 'Dokumenttyp',
      dataIndex: 'document_type',
      key: 'doctype',
      render: getDocTypeName,
    },
    {
      title: 'Titel',
      dataIndex: 'title',
      key: 'title',
      ellipsis: true,
    },
    {
      title: 'Erstellt',
      dataIndex: 'created_date',
      key: 'created',
      width: 110,
      render: (v: string) => v ? dayjs(v).format('DD.MM.YYYY') : '—',
    },
    {
      title: 'Absender',
      dataIndex: 'correspondent',
      key: 'correspondent',
      render: getCorrespondentName,
    },
    {
      title: 'Freigabe',
      key: 'freigabe',
      width: 140,
      render: (_, doc) => getFreigabeValue(doc),
    },
    {
      title: '',
      key: 'action',
      width: 130,
      render: (_, doc) => (
        <Button
          icon={<CheckCircleOutlined />}
          size="small"
          type="primary"
          onClick={() => openModal(doc)}
        >
          Freigabe setzen
        </Button>
      ),
    },
  ];

  return (
    <>
      <Title level={4} style={{ marginTop: 0, marginBottom: 16 }}>Freigabe</Title>

      <Space style={{ marginBottom: 16 }}>
        <Radio.Group
          value={nurNichtFreigegeben}
          onChange={(e) => {
            setPage(1);
            setNurNichtFreigegeben(e.target.value);
          }}
          optionType="button"
          buttonStyle="solid"
        >
          <Radio.Button value={true}>Nicht freigegeben</Radio.Button>
          <Radio.Button value={false}>Alle</Radio.Button>
        </Radio.Group>
      </Space>

      <Table<FreigabeDocument>
        dataSource={data}
        columns={columns}
        rowKey="id"
        loading={loading}
        size="small"
        pagination={{
          current: page,
          pageSize,
          total,
          showSizeChanger: true,
          pageSizeOptions: ['25', '50', '100'],
          onChange: (p, ps) => {
            setPage(p);
            setPageSize(ps);
          },
          showTotal: (t) => `${t} Belege`,
        }}
      />

      <Modal
        title="Freigabe setzen"
        open={modalOpen}
        onOk={handleFreigabe}
        onCancel={() => { setModalOpen(false); setSelectedDoc(null); }}
        okText="Speichern"
        cancelText="Abbrechen"
        confirmLoading={saving}
      >
        <p style={{ marginBottom: 12 }}>
          <strong>{selectedDoc?.title}</strong>
        </p>
        <Select
          style={{ width: '100%' }}
          placeholder="Freigabe-Status wählen"
          allowClear
          value={selectedValue ?? undefined}
          onChange={(v) => setSelectedValue(v ?? null)}
          options={freigabeOptions.map((o) => ({ value: o.id, label: o.label }))}
        />
      </Modal>
    </>
  );
}