import { assertSafeSqlIdentifier } from './user-data-space-service.mjs';

export const PAGE_DATA_VISITOR_ROLES = new Set(['viewer', 'editor', 'owner']);

export const DEFAULT_ROLE_PERMISSIONS = {
  viewer: { read: true, insert: false, update: false, softDelete: false },
  editor: { read: true, insert: true, update: true, softDelete: true },
  owner: { read: true, insert: true, update: true, softDelete: true, hardDelete: false },
};

export function normalizeRowPolicy(raw) {
  if (!raw || typeof raw !== 'object') return null;
  const scope = String(raw.scope ?? 'all_rows').trim();
  if (!['all_rows', 'own_rows', 'owner_only'].includes(scope)) {
    throw Object.assign(new Error(`不支持的 rowPolicy.scope：${scope}`), { code: 'invalid_policy' });
  }
  const ownerColumn = assertSafeSqlIdentifier(
    raw.ownerColumn ?? raw.owner_column ?? 'created_by_user_id',
    'rowPolicy.ownerColumn',
  );
  return { scope, ownerColumn };
}

export function normalizeVisitorAssignments(raw) {
  if (!raw || typeof raw !== 'object') return {};
  const visitors = {};
  for (const [userId, value] of Object.entries(raw)) {
    const visitorId = String(userId ?? '').trim();
    if (!visitorId) continue;
    const role = typeof value === 'string' ? value.trim() : String(value?.role ?? '').trim();
    if (!PAGE_DATA_VISITOR_ROLES.has(role) || role === 'owner') {
      throw Object.assign(new Error(`访问者角色无效：${role}`), { code: 'invalid_policy' });
    }
    visitors[visitorId] = role;
  }
  return visitors;
}

export function normalizeRoleOverrides(raw) {
  if (!raw || typeof raw !== 'object') return {};
  const roles = {};
  for (const [roleName, permissions] of Object.entries(raw)) {
    const role = String(roleName ?? '').trim();
    if (!PAGE_DATA_VISITOR_ROLES.has(role)) {
      throw Object.assign(new Error(`角色定义无效：${role}`), { code: 'invalid_policy' });
    }
    roles[role] = {
      read: Boolean(permissions?.read),
      insert: Boolean(permissions?.insert),
      update: Boolean(permissions?.update),
      softDelete: Boolean(permissions?.softDelete ?? permissions?.soft_delete),
      hardDelete: Boolean(permissions?.hardDelete ?? permissions?.hard_delete),
    };
  }
  return roles;
}

export function resolveVisitorRole(policy, visitorUserId) {
  const visitorId = String(visitorUserId ?? '').trim();
  if (!visitorId) return null;
  if (visitorId === policy.ownerUserId) return 'owner';
  const assigned = policy.visitors?.[visitorId];
  if (assigned) return assigned;
  const defaultRole = String(policy.defaultVisitorRole ?? 'deny').trim();
  if (defaultRole === 'deny') return null;
  if (!PAGE_DATA_VISITOR_ROLES.has(defaultRole)) return null;
  return defaultRole;
}

export function resolveRolePermissions(policy, role) {
  const defaults = DEFAULT_ROLE_PERMISSIONS[role] ?? DEFAULT_ROLE_PERMISSIONS.viewer;
  const overrides = policy.roles?.[role];
  if (!overrides) return { ...defaults };
  return {
    read: overrides.read ?? defaults.read,
    insert: overrides.insert ?? defaults.insert,
    update: overrides.update ?? defaults.update,
    softDelete: overrides.softDelete ?? defaults.softDelete,
    hardDelete: overrides.hardDelete ?? defaults.hardDelete,
  };
}

export function roleAllowsAction(rolePermissions, action) {
  if (!rolePermissions) return false;
  if (action === 'read') return Boolean(rolePermissions.read);
  if (action === 'insert') return Boolean(rolePermissions.insert);
  if (action === 'update') return Boolean(rolePermissions.update);
  if (action === 'soft_delete') return Boolean(rolePermissions.softDelete);
  if (action === 'hard_delete') return Boolean(rolePermissions.hardDelete);
  return false;
}

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

export function resolveRowAccessScope(rowPolicy, {
  visitorRole,
  visitorUserId,
  ownerUserId,
  tableColumns = [],
} = {}) {
  if (!rowPolicy || rowPolicy.scope === 'all_rows') {
    return { bypass: true, whereClause: null, ownerColumn: null, visitorUserId };
  }
  const isOwner = visitorRole === 'owner' || visitorUserId === ownerUserId;
  if (rowPolicy.scope === 'owner_only') {
    if (isOwner) return { bypass: true, whereClause: null, ownerColumn: null, visitorUserId };
    throw Object.assign(new Error('当前数据集仅页面所有者可访问'), { code: 'row_not_allowed' });
  }
  if (rowPolicy.scope === 'own_rows') {
    if (isOwner) return { bypass: true, whereClause: null, ownerColumn: rowPolicy.ownerColumn, visitorUserId };
    const column = rowPolicy.ownerColumn;
    const hasColumn = tableColumns.some((item) => item.name === column);
    if (!hasColumn) {
      throw Object.assign(new Error(`行级权限列不存在：${column}`), { code: 'row_policy_invalid' });
    }
    const safeVisitorId = String(visitorUserId ?? '').replace(/'/g, "''");
    return {
      bypass: false,
      whereClause: `"${column}" = '${safeVisitorId}'`,
      ownerColumn: column,
      visitorUserId,
    };
  }
  return { bypass: true, whereClause: null, ownerColumn: null, visitorUserId };
}