import {
  OPERATORS,
  UserOrProjectQuery,
  isToOperand,
  SUPPORTED_TIME_UNITS,
} from "@cocalc/util/schema";
import { quoteField } from "../postgres/schema/util";
import { is_object } from "@cocalc/util/misc";

export function queryIsCmp(val): false | string {
  if (!is_object(val)) {
    return false;
  }
  const keys = Object.keys(val);
  if (keys.length != 1) {
    return false;
  }
  if (OPERATORS.includes(keys[0] as any)) {
    return keys[0];
  }
  return false;
}

// Additional where object condition imposed by user's get query
export function userGetQueryFilter(
  user_query: object,
  client_query: UserOrProjectQuery<any>
): { [expr: string]: any } {
  if (client_query.get == null) {
    // no get queries allowed (this is mainly to make typescript happy below.)
    return {};
  }

  // If the schema lists the value in a get query as 'null', then we remove it;
  // nulls means it was only there to be used by the initial where filter
  // part of the query.
  for (const field in client_query.get.fields) {
    const val = client_query.get.fields[field];
    if (val === "null") {
      delete user_query[field];
    }
  }

  const where: { [expr: string]: any } = {};
  for (const field in user_query) {
    const val = user_query[field];
    if (val == null) continue;
    if (
      client_query.get.remove_from_query != null &&
      client_query.get.remove_from_query.includes(field)
    ) {
      // do not include any field that explicitly excluded from the query
      continue;
    }
    if (!queryIsCmp(val)) {
      where[`${quoteField(field)} = $`] = val;
      continue;
    }

    // It's a comparison query, e.g., {field : {'<=' : 5}}
    for (let op in val) {
      const v = val[op];
      if (op === "==") {
        // not in SQL, but natural for our clients to use it
        op = "=";
      }
      if (op.toLowerCase().startsWith("is")) {
        // hack to use same where format for now, since $ replacement
        // doesn't work for "foo IS ...".
        where[`${quoteField(field)} ${op} ${isToOperand(v)}`] = true;
      } else if (
        is_object(v) &&
        v["relative_time"] != null &&
        SUPPORTED_TIME_UNITS.includes(v["unit"])
      ) {
        const time = parseInt(v["relative_time"]);
        // ${v["unit"]} is safe because we checked that it is in SUPPORTED_TIME_UNITS above.
        // Also see https://stackoverflow.com/questions/7796657/using-a-variable-period-in-an-interval-in-postgres
        // for how we do this "interval" arithmetic.
        const int = `NOW() + $ * INTERVAL '1 ${v["unit"]}'`;
        const expr = `${quoteField(field)} ${op} (${int})`;
        where[expr] = time;
      } else {
        where[`${quoteField(field)} ${op} $`] = v;
      }
    }
  }

  return where;
}