import { assertSafeSqlIdentifier, normalizeDatasetConfig } from './user-data-space-service.mjs';
import {
  normalizeRowPolicy,
  normalizeRoleOverrides,
  normalizeVisitorAssignments,
} from './page-access-visitor.mjs';

export const PAGE_DATA_ACCESS_MODES = new Set(['public', 'password', 'login_required']);

export function normalizePolicyDataset(name, raw) {
  const datasetName = assertSafeSqlIdentifier(name, 'dataset 名称');
  if (!raw || typeof raw !== 'object') {
    throw Object.assign(new Error(`dataset 策略无效：${datasetName}`), { code: 'invalid_policy' });
  }
  const columns = raw.columns && typeof raw.columns === 'object' ? raw.columns : {};
  const normalizedColumns = {};
  for (const [action, fields] of Object.entries(columns)) {
    if (!Array.isArray(fields)) continue;
    normalizedColumns[action] = fields.map((field) => assertSafeSqlIdentifier(field, `${action} 字段`));
  }
  return {
    name: datasetName,
    read: Boolean(raw.read),
    insert: Boolean(raw.insert),
    update: Boolean(raw.update),
    softDelete: Boolean(raw.softDelete ?? raw.soft_delete),
    // `delete` is the page-facing spelling for an intentional permanent PG
    // delete; retain hardDelete for existing policies.
    hardDelete: Boolean(raw.hardDelete ?? raw.hard_delete ?? raw.delete),
    columns: normalizedColumns,
    limits:
      raw.limits && typeof raw.limits === 'object'
        ? {
            maxRowsPerRead: Number(raw.limits.maxRowsPerRead ?? 100),
            maxInsertBytes: Number(raw.limits.maxInsertBytes ?? 8192),
          }
        : undefined,
    rowPolicy: normalizeRowPolicy(raw.rowPolicy ?? raw.row_policy),
    closed: Boolean(raw.closed),
    closedAt: raw.closedAt ?? raw.closed_at ?? null,
  };
}

export function normalizePageAccessPolicy(raw, { fallbackPageId = null, fallbackOwnerUserId = null } = {}) {
  if (!raw || typeof raw !== 'object') {
    throw Object.assign(new Error('Page Access Policy 无效'), { code: 'invalid_policy' });
  }
  const pageId = String(raw.pageId ?? fallbackPageId ?? '').trim();
  const ownerUserId = String(raw.ownerUserId ?? fallbackOwnerUserId ?? '').trim();
  if (!pageId) throw Object.assign(new Error('缺少 pageId'), { code: 'invalid_policy' });
  if (!ownerUserId) throw Object.assign(new Error('缺少 ownerUserId'), { code: 'invalid_policy' });
  const accessMode = String(raw.accessMode ?? raw.access_mode ?? 'public').trim();
  if (!PAGE_DATA_ACCESS_MODES.has(accessMode)) {
    throw Object.assign(new Error(`不支持的 accessMode：${accessMode}`), { code: 'invalid_policy' });
  }
  const datasetsInput = raw.datasets && typeof raw.datasets === 'object' ? raw.datasets : {};
  const datasets = {};
  for (const [name, config] of Object.entries(datasetsInput)) {
    datasets[assertSafeSqlIdentifier(name, 'dataset 名称')] = normalizePolicyDataset(name, config);
  }
  const defaultVisitorRole = String(
    raw.defaultVisitorRole ??
      raw.default_visitor_role ??
      (accessMode === 'login_required' ? 'viewer' : 'deny'),
  ).trim();
  if (!['deny', 'viewer', 'editor'].includes(defaultVisitorRole)) {
    throw Object.assign(new Error(`不支持的 defaultVisitorRole：${defaultVisitorRole}`), {
      code: 'invalid_policy',
    });
  }
  return {
    pageId,
    ownerUserId,
    workspaceRef: String(raw.workspaceRef ?? raw.workspace_ref ?? '').trim() || null,
    accessMode,
    defaultVisitorRole,
    visitors: normalizeVisitorAssignments(raw.visitors),
    roles: normalizeRoleOverrides(raw.roles),
    datasets,
    updatedAt: raw.updatedAt ?? new Date().toISOString(),
  };
}

export function buildEffectiveDataset(registryDataset, policyDataset) {
  if (!registryDataset || !policyDataset) return null;
  const actions = [];
  if (policyDataset.read) actions.push('read');
  if (policyDataset.insert) actions.push('insert');
  if (policyDataset.update) actions.push('update');
  if (policyDataset.softDelete) actions.push('soft_delete');
  if (policyDataset.hardDelete) actions.push('hard_delete');
  const columns = {
    read: policyDataset.columns?.read ?? registryDataset.columns?.read ?? [],
    insert: policyDataset.columns?.insert ?? registryDataset.columns?.insert ?? [],
    update: policyDataset.columns?.update ?? registryDataset.columns?.update ?? [],
    soft_delete: policyDataset.columns?.soft_delete ?? registryDataset.columns?.soft_delete ?? ['id'],
  };
  return normalizeDatasetConfig({
    name: registryDataset.name,
    table: registryDataset.table,
    description: registryDataset.description,
    actions,
    columns,
    limits: policyDataset.limits ?? registryDataset.limits,
  });
}

export async function assertPageAccessPolicyMatchesRegistry(policy, userDataSpace) {
  if (!userDataSpace?.getDataset) {
    throw Object.assign(new Error('缺少 Page Data 数据空间'), {
      code: 'feature_disabled',
      status: 503,
    });
  }

  const actionFlags = [
    ['read', 'read'],
    ['insert', 'insert'],
    ['update', 'update'],
    ['softDelete', 'soft_delete'],
    ['hardDelete', 'hard_delete'],
  ];
  const columnGroups = ['read', 'insert', 'update', 'soft_delete'];

  for (const [datasetName, policyDataset] of Object.entries(policy?.datasets ?? {})) {
    const registryDataset = await userDataSpace.getDataset(datasetName);
    if (!registryDataset) {
      throw Object.assign(new Error(`dataset 未注册：${datasetName}`), {
        code: 'dataset_not_found',
        status: 404,
        datasetName,
      });
    }

    const tableColumns = await userDataSpace.listTableColumns?.(registryDataset.table);
    if (!Array.isArray(tableColumns) || tableColumns.length === 0) {
      throw Object.assign(new Error(`dataset 对应表不存在：${registryDataset.table}`), {
        code: 'table_not_found',
        status: 404,
        datasetName,
        table: registryDataset.table,
      });
    }
    const actualColumnNames = new Set(tableColumns.map((column) => column.name));
    const missingRegistryColumns = [
      ...new Set(Object.values(registryDataset.columns ?? {}).flat()),
    ].filter((column) => !actualColumnNames.has(column));
    if (missingRegistryColumns.length) {
      throw Object.assign(
        new Error(
          `dataset「${datasetName}」注册字段不存在：${missingRegistryColumns.join(', ')}`,
        ),
        {
          code: 'dataset_schema_mismatch',
          status: 409,
          datasetName,
          columns: missingRegistryColumns,
        },
      );
    }

    const registeredActions = new Set(registryDataset.actions ?? []);
    for (const [policyFlag, registryAction] of actionFlags) {
      if (policyDataset?.[policyFlag] && !registeredActions.has(registryAction)) {
        throw Object.assign(
          new Error(`dataset「${datasetName}」未注册 ${registryAction} 权限`),
          {
            code: 'action_not_allowed',
            status: 403,
            datasetName,
            action: registryAction,
          },
        );
      }
    }

    for (const action of columnGroups) {
      const requestedColumns = policyDataset?.columns?.[action];
      if (!Array.isArray(requestedColumns)) continue;
      const registeredColumns = new Set(registryDataset.columns?.[action] ?? []);
      const unregisteredColumns = requestedColumns.filter(
        (column) => !registeredColumns.has(column),
      );
      if (unregisteredColumns.length) {
        throw Object.assign(
          new Error(
            `dataset「${datasetName}」的 ${action} 字段未注册：${unregisteredColumns.join(', ')}`,
          ),
          {
            code: 'columns_not_allowed',
            status: 403,
            datasetName,
            action,
            columns: unregisteredColumns,
          },
        );
      }
    }
  }

  return policy;
}

export function defaultDatasetsForAccessMode(accessMode, datasets = {}) {
  const normalized = {};
  for (const [name, config] of Object.entries(datasets)) {
    const base = normalizePolicyDataset(name, config);
    if (accessMode === 'public') {
      normalized[name] = {
        ...base,
        read: false,
        update: false,
        softDelete: false,
        hardDelete: false,
      };
    } else if (accessMode === 'password') {
      normalized[name] = {
        ...base,
        hardDelete: false,
      };
    } else {
      normalized[name] = {
        ...base,
        hardDelete: false,
      };
    }
  }
  return normalized;
}

export function policyAllowsAction(policy, datasetName, action) {
  const dataset = policy?.datasets?.[datasetName];
  if (!dataset) return false;
  if (dataset.closed) return false;
  if (action === 'read') return dataset.read;
  if (action === 'insert') return dataset.insert;
  if (action === 'update') return dataset.update;
  if (action === 'soft_delete') return dataset.softDelete;
  if (action === 'hard_delete') return dataset.hardDelete;
  return false;
}

export function closePolicyDataset(policy, datasetName) {
  const dataset = policy?.datasets?.[datasetName];
  if (!dataset) {
    throw Object.assign(new Error('dataset 未授权'), { code: 'dataset_not_found' });
  }
  return {
    ...policy,
    datasets: {
      ...policy.datasets,
      [datasetName]: {
        ...dataset,
        read: false,
        insert: false,
        update: false,
        softDelete: false,
        hardDelete: false,
        closed: true,
        closedAt: new Date().toISOString(),
      },
    },
    updatedAt: new Date().toISOString(),
  };
}

export function mapPublicationAccessModeToPageData(accessMode) {
  const mode = String(accessMode ?? '').trim();
  if (PAGE_DATA_ACCESS_MODES.has(mode)) return mode;
  return null;
}

export function buildDatasetPolicyFromRegistry(
  registryDataset,
  { read = false, insert = false, update = false, softDelete = false, accessMode = 'public' } = {},
) {
  const rowPolicy =
    accessMode === 'login_required' && (update || softDelete || read)
      ? { scope: 'own_rows', ownerColumn: 'created_by_user_id' }
      : null;
  return normalizePolicyDataset(registryDataset?.name ?? 'dataset', {
    read: Boolean(read),
    insert: Boolean(insert),
    update: Boolean(update),
    softDelete: Boolean(softDelete),
    columns: {
      read: registryDataset?.columns?.read ?? [],
      insert: registryDataset?.columns?.insert ?? [],
      update: registryDataset?.columns?.update ?? [],
      soft_delete: registryDataset?.columns?.soft_delete ?? ['id'],
    },
    rowPolicy,
  });
}

export function buildPageDataPolicyFromPublishInput({
  pageId,
  ownerUserId,
  accessMode,
  datasetName,
  registryDataset,
  capabilities = {},
}) {
  const mappedAccessMode = mapPublicationAccessModeToPageData(accessMode);
  if (!mappedAccessMode) {
    throw Object.assign(new Error('当前发布访问模式不支持 Page Data'), { code: 'invalid_policy' });
  }
  const defaults =
    mappedAccessMode === 'public'
      ? { read: false, insert: true, update: false, softDelete: false }
      : mappedAccessMode === 'password'
        ? { read: true, insert: true, update: false, softDelete: false }
        : { read: true, insert: true, update: true, softDelete: false };
  const datasetPolicy = buildDatasetPolicyFromRegistry(registryDataset, {
    read: capabilities.read ?? defaults.read,
    insert: capabilities.insert ?? defaults.insert,
    update: capabilities.update ?? defaults.update,
    softDelete: capabilities.softDelete ?? defaults.softDelete,
    accessMode: mappedAccessMode,
  });
  return normalizePageAccessPolicy(
    {
      pageId,
      ownerUserId,
      accessMode: mappedAccessMode,
      datasets: {
        [datasetName]: datasetPolicy,
      },
    },
    { fallbackPageId: pageId, fallbackOwnerUserId: ownerUserId },
  );
}