import { useCallback, useEffect, useRef, useState } from 'react';
import { useNavigate } from 'react-router-dom';
import { useTranslation } from 'react-i18next';
import { Play, Plus, Trash2, Download, ClipboardList } from 'lucide-react';
import { parse as yamlParse } from 'yaml';
import { environments, scenarios } from '../../api';
import type { Environment, Scenario } from '../../api';
import {
  Breadcrumbs,
  Button,
  Modal,
  Select,
  Table,
  type TableColumn,
  Timestamp,
  UuidBadge,
  useToast,
} from '../../ui';
import styles from '../Page.module.css';

export function ScenariosPage() {
  const { t } = useTranslation();
  const navigate = useNavigate();
  const toast = useToast();
  const [items, setItems] = useState<Scenario[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [deleteId, setDeleteId] = useState<string | null>(null);
  const [deleting, setDeleting] = useState(false);
  const [runScenarioId, setRunScenarioId] = useState<string | null>(null);
  const [running, setRunning] = useState(false);
  const [saveSessionFlag, setSaveSessionFlag] = useState(false);
  const [envs, setEnvs] = useState<Environment[]>([]);
  const [selectedEnvId, setSelectedEnvId] = useState('');

  const fileInputRef = useRef<HTMLInputElement>(null);

  const load = useCallback(() => {
    Promise.all([scenarios.list(), environments.list(1, 200)])
      .then(([scenarioRes, envRes]) => {
        setItems(scenarioRes.data);
        setEnvs(envRes.data);
      })
      .catch((err: Error) => setError(err.message))
      .finally(() => setLoading(false));
  }, []);

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

  const openRunModal = (id: string) => {
    setRunScenarioId(id);
    if (!selectedEnvId && envs.length > 0) {
      setSelectedEnvId(envs[0].id);
    }
  };

  const handleRun = async () => {
    if (!runScenarioId || !selectedEnvId) return;
    setRunning(true);
    try {
      const run = await scenarios.run(runScenarioId, selectedEnvId, saveSessionFlag);
      toast.success('Scenario run started');
      navigate(`/scenarios/${runScenarioId}/runs/${run.id}`);
      setRunScenarioId(null);
      setSaveSessionFlag(false);
    } catch (err) {
      toast.error((err as Error).message);
    } finally {
      setRunning(false);
    }
  };

  const handleDelete = async () => {
    if (!deleteId) return;
    setDeleting(true);
    try {
      await scenarios.remove(deleteId);
      setLoading(true);
      load();
      setDeleteId(null);
    } finally {
      setDeleting(false);
    }
  };

  const handleImport = async (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (!file) return;
    e.target.value = '';
    try {
      const text = await file.text();
      const payload = yamlParse(text) as unknown;
      const imported = await scenarios.importScenario(payload);
      navigate(`/scenarios/${imported.id}`);
    } catch (err) {
      setError((err as Error).message);
    }
  };

  const columns: TableColumn<Scenario>[] = [
    { key: 'id', header: t('scenarios.col_id'), render: (s) => <UuidBadge id={s.id} />, width: 60 },
    { key: 'name', header: t('scenarios.col_name'), render: (s) => s.name },
    {
      key: 'updated',
      header: t('scenarios.col_updated'),
      width: 140,
      render: (s) => <Timestamp value={s.updatedAt} />,
    },
    {
      key: 'actions',
      header: '',
      width: 100,
      align: 'right',
      render: (s) => (
        <span style={{ display: 'inline-flex', gap: 6 }}>
          <Button
            size="sm"
            title={t('scenarios.action_run')}
            onClick={(e) => {
              e.stopPropagation();
              openRunModal(s.id);
            }}
          >
            <Play size={14} />
          </Button>
          <Button
            variant="danger"
            size="sm"
            title={t('scenarios.action_delete')}
            onClick={(e) => {
              e.stopPropagation();
              setDeleteId(s.id);
            }}
          >
            <Trash2 size={14} />
          </Button>
        </span>
      ),
    },
  ];

  return (
    <div>
      <div className={styles.pageToolbar}>
        <Breadcrumbs items={[{ label: t('scenarios.title'), icon: <ClipboardList size={14} /> }]} />
        <div className={styles.toolbarActions}>
          <input
            ref={fileInputRef}
            type="file"
            accept=".yaml,.yml,.json"
            style={{ display: 'none' }}
            onChange={handleImport}
          />
          <Button variant="secondary" size="sm" onClick={() => fileInputRef.current?.click()}>
            <Download size={14} />
            {t('scenarios.action_import')}
          </Button>
          <Button size="sm" onClick={() => navigate('/scenarios/new')}>
            <Plus size={14} />
            {t('scenarios.action_add')}
          </Button>
        </div>
      </div>
      <Table
        columns={columns}
        data={items}
        rowKey={(s) => s.id}
        loading={loading}
        emptyMessage={t('scenarios.empty')}
        pageSize={10}
        pageSizeOptions={[10, 25, 50]}
        onRowClick={(s) => navigate(`/scenarios/${s.id}`)}
      />

      <Modal
        open={deleteId != null}
        title={t('scenarios.action_delete')}
        onClose={() => !deleting && setDeleteId(null)}
        footer={(
          <>
            <Button variant="secondary" onClick={() => setDeleteId(null)} disabled={deleting}>
              Cancel
            </Button>
            <Button variant="danger" onClick={handleDelete} disabled={deleting}>
              {t('scenarios.action_delete')}
            </Button>
          </>
        )}
      >
        Are you sure you want to delete this scenario?
      </Modal>

      <Modal
        open={runScenarioId != null}
        title={t('scenarios.run_modal_title')}
        onClose={() => !running && setRunScenarioId(null)}
        footer={(
          <>
            <Button variant="secondary" onClick={() => setRunScenarioId(null)} disabled={running}>
              Cancel
            </Button>
            <Button variant="primary" onClick={handleRun} disabled={running || !selectedEnvId}>
              {t('scenarios.action_run')}
            </Button>
          </>
        )}
      >
        {envs.length === 0 ? (
          <p>{t('scenarios.run_modal_no_env')}</p>
        ) : (
          <>
            <Select
              label={t('scenarios.run_modal_env_label')}
              value={selectedEnvId}
              onChange={(e) => setSelectedEnvId(e.target.value)}
              options={envs.map((env) => ({ value: env.id, label: env.name }))}
            />
            <label style={{ display: 'flex', alignItems: 'center', marginTop: '1rem', gap: '0.5rem' }}>
              <input
                type="checkbox"
                checked={saveSessionFlag}
                onChange={(e) => setSaveSessionFlag(e.target.checked)}
              />
              <span>Save session</span>
            </label>
          </>
        )}
      </Modal>
    </div>
  );
}