import type {
  QueryCondition,
  QueryConditionNumber,
  QueryConditionText,
  QueryFilter,
} from '@morten-olsen/stash-query-dsl';
import { type Knex } from 'knex';
/**
 * Escapes a JSON key for use in PostgreSQL JSON operators.
 * Escapes single quotes by doubling them, which is the PostgreSQL standard.
 */
const escapeJsonKey = (key: string): string => {
  return key.replace(/'/g, "''");
};

const getFieldSelector = (query: Knex.QueryBuilder, field: string[], tableName?: string) => {
  const baseColumn = field[0];
  if (field.length === 1) {
    return tableName ? `${tableName}.${baseColumn}` : baseColumn;
  }

  const baseFieldRef = tableName ? query.client.ref(baseColumn).withSchema(tableName) : query.client.ref(baseColumn);
  const jsonPath = field.slice(1);
  let sqlExpression = baseFieldRef.toString();

  for (let i = 0; i < jsonPath.length - 1; i++) {
    const escapedKey = escapeJsonKey(jsonPath[i]);
    sqlExpression += ` -> '${escapedKey}'`;
  }

  const finalElement = jsonPath[jsonPath.length - 1];
  const escapedFinalKey = escapeJsonKey(finalElement);
  sqlExpression += ` ->> '${escapedFinalKey}'`;
  return query.client.raw(sqlExpression);
};

const applyQueryConditionText = (query: Knex.QueryBuilder, { field, tableName, conditions }: QueryConditionText) => {
  const selector = getFieldSelector(query, field, tableName);
  if (conditions.equal) {
    query = query.where(selector, '=', conditions.equal);
  }
  if (conditions.notEqual) {
    query = query.where(selector, '<>', conditions.notEqual);
  }
  if (conditions.like) {
    query = query.whereLike(selector, conditions.like);
  }
  if (conditions.notLike) {
    query = query.not.whereLike(selector, conditions.notLike);
  }
  if (conditions.equal === null) {
    query = query.whereNull(selector);
  }
  if (conditions.notEqual === null) {
    query = query.whereNotNull(selector);
  }
  if (conditions.in) {
    query = query.whereIn(selector, conditions.in);
  }
  if (conditions.notIn) {
    query = query.whereNotIn(selector, conditions.notIn);
  }
  return query;
};

const applyQueryConditionNumber = (
  query: Knex.QueryBuilder,
  { field, tableName, conditions }: QueryConditionNumber,
) => {
  const selector = getFieldSelector(query, field, tableName);
  if (conditions.equals !== undefined && conditions.equals !== null) {
    query = query.where(selector, '=', conditions.equals);
  }
  if (conditions.notEquals !== undefined && conditions.notEquals !== null) {
    query = query.where(selector, '<>', conditions.notEquals);
  }
  if (conditions.equals === null) {
    query = query.whereNull(selector);
  }
  if (conditions.notEquals === null) {
    query = query.whereNotNull(selector);
  }
  if (conditions.greaterThan) {
    query = query.where(selector, '>', conditions.greaterThan);
  }
  if (conditions.greaterThanOrEqual) {
    query = query.where(selector, '>=', conditions.greaterThanOrEqual);
  }
  if (conditions.lessThan) {
    query = query.where(selector, '<', conditions.lessThan);
  }
  if (conditions.lessThanOrEqual) {
    query = query.where(selector, '<=', conditions.lessThanOrEqual);
  }
  if (conditions.in) {
    query = query.whereIn(selector, conditions.in);
  }
  if (conditions.notIn) {
    query = query.whereNotIn(selector, conditions.notIn);
  }
  return query;
};

const applyQueryCondition = (query: Knex.QueryBuilder, options: QueryCondition) => {
  switch (options.type) {
    case 'text': {
      return applyQueryConditionText(query, options);
    }
    case 'number': {
      return applyQueryConditionNumber(query, options);
    }
    default: {
      throw new Error(`Unknown filter type`);
    }
  }
};

const applyQueryFilter = (query: Knex.QueryBuilder, filter: QueryFilter) => {
  if (filter.type === 'operator') {
    if (filter.conditions.length === 0) {
      return query;
    }

    switch (filter.operator) {
      case 'or': {
        return query.where((subquery) => {
          let isFirst = true;
          for (const condition of filter.conditions) {
            if (isFirst) {
              applyQueryFilter(subquery, condition);
              isFirst = false;
            } else {
              subquery.orWhere((subSubquery) => {
                applyQueryFilter(subSubquery, condition);
              });
            }
          }
        });
      }
      case 'and': {
        return query.where((subquery) => {
          let isFirst = true;
          for (const condition of filter.conditions) {
            if (isFirst) {
              applyQueryFilter(subquery, condition);
              isFirst = false;
            } else {
              subquery.andWhere((subSubquery) => {
                applyQueryFilter(subSubquery, condition);
              });
            }
          }
        });
      }
    }
  } else {
    return applyQueryCondition(query, filter);
  }
};

export { applyQueryCondition, applyQueryFilter };