import { Brackets, DataSource, ObjectLiteral, SelectQueryBuilder } from "typeorm";
import { dataSource } from "../data-source";
import { ConditionStructure, DynamicQueryStructure } from "../type/dynamicQueries";
import { TableMeta } from "../type/tableMeta";

export default abstract class DynamicQueryBuilder {
  public static allowedTables: Array<string> = [
    "award",
    "communication",
    "communicationType",
    "executivePosition",
    "membershipStatus",
    "qualification",
    "member",
    "memberAwards",
    "memberExecutivePositions",
    "memberQualifications",
    "membership",
  ];

  public static getTableMeta(tableName: string): TableMeta {
    let { name, columns, relations } = dataSource.getMetadata(tableName);

    const uniqueColumns = columns.map((c) => ({ column: c.propertyName, type: c.type }));

    return {
      tableName: name,
      columns: [
        ...uniqueColumns,
        ...relations
          .filter((r) => !uniqueColumns.some((c) => r.propertyName == c.column))
          .map((r) => ({
            column: r.propertyName,
            type: r.inverseEntityMetadata?.columns.find((col) => col.propertyName === r.inverseSidePropertyPath)?.type,
          })),
      ],
      relations: relations.map((r) => ({
        column: r.propertyName,
        relationType: r.relationType,
        referencedTableName: r.inverseEntityMetadata?.tableName,
      })),
    };
  }

  public static getAllTableMeta(): Array<TableMeta> {
    return this.allowedTables.map((table) => this.getTableMeta(table));
  }

  public static buildQuery(
    queryObj: DynamicQueryStructure,
    offset: number = 0,
    count: number = 25
  ): SelectQueryBuilder<ObjectLiteral> {
    let query = dataSource.getRepository(queryObj.table).createQueryBuilder(queryObj.table + "_0");
    query = this.buildDynamicQuery(query, queryObj);
    query = query.offset(offset);
    query = query.limit(count);

    return query;

    dataSource
      .getRepository("member")
      .createQueryBuilder("member_0")
      .select("member_0.firstname")
      .addSelect("member_0.lastname")
      .where("member_0.mail LIKE '%@gmail.com'")
      .andWhere(
        new Brackets((qb) => {
          qb.where("user.firstName LIKE '%J'").orWhere("user.lastName LIKE '%K'");
        })
      )
      .leftJoinAndSelect("member_0.sendNewsletter", "communication_0")
      .addSelect("communication_0.*")
      .orderBy("member_0.firstname", "ASC")
      .addOrderBy("member_0.lastname", "ASC");
  }

  public static buildDynamicQuery(
    queryBuilder: SelectQueryBuilder<ObjectLiteral>,
    queryObject: DynamicQueryStructure,
    depth: number = 0
  ): SelectQueryBuilder<ObjectLiteral> {
    const alias = queryObject.table + "_" + depth;

    // Handle SELECT
    if (queryObject.select == "*") {
      queryBuilder.select(`${alias}.*`);
    } else {
      queryBuilder.select(queryObject.select.map((col) => `${alias}.${col}`));
    }

    // Handle WHERE
    if (queryObject.where) {
      this.applyWhere(queryBuilder, queryObject.where, alias);
    }

    // Handle JOINS
    if (queryObject.join) {
      queryObject.join.forEach((join) => {
        const joinAlias = join.table;
        const joinType = "leftJoin"; // Default join type
        const joinCondition = `${alias}.${join.foreignColumn} = ${joinAlias}.${join.foreignColumn}`;

        queryBuilder[joinType](`${join.table}`, joinAlias, joinCondition);

        // Recursively handle sub-joins and their conditions
        this.buildDynamicQuery(queryBuilder, join, depth + 1);
      });
    }

    // Handle ORDER BY
    if (queryObject.orderBy) {
      queryObject.orderBy.forEach((order) => {
        queryBuilder.addOrderBy(`${alias}.${order.column}`, order.order);
      });
    }

    return queryBuilder;
  }

  // Helper: Apply WHERE conditions
  public static applyWhere<T>(
    queryBuilder: SelectQueryBuilder<T>,
    conditions: Array<ConditionStructure>,
    alias: string
  ): void {
    conditions.forEach((condition, index) => {
      if (condition.structureType === "condition") {
        const whereClause = this.buildConditionClause(condition, alias);
        const whereMethod = condition.concat === "_" ? "where" : "andWhere";

        if (condition.concat === "OR") {
          queryBuilder.orWhere(whereClause.query, whereClause.parameters);
        } else {
          queryBuilder[whereMethod](whereClause.query, whereClause.parameters);
        }
      } else if (condition.structureType === "nested") {
        const nestedQuery = this.conditionsToQuery(condition.condition, alias);
        const whereMethod = condition.concat === "OR" ? "orWhere" : "andWhere";

        queryBuilder[whereMethod](`(${nestedQuery.query})`, nestedQuery.parameters);
      }
    });
  }

  // Helper: Build a single condition clause
  public static buildConditionClause(
    condition: ConditionStructure,
    alias: string
  ): { query: string; parameters: Record<string, unknown> } {
    if (condition.structureType == "nested") return;
    const parameterKey = `${alias}_${condition.column}_${Math.random().toString(36).substring(2)}`;
    let query = `${alias}.${condition.column}`;
    let parameters: Record<string, unknown> = {};

    switch (condition.operation) {
      case "eq":
        query += ` = :${parameterKey}`;
        parameters[parameterKey] = condition.value;
        break;
      case "neq":
        query += ` != :${parameterKey}`;
        parameters[parameterKey] = condition.value;
        break;
      case "lt":
        query += ` < :${parameterKey}`;
        parameters[parameterKey] = condition.value;
        break;
      case "lte":
        query += ` <= :${parameterKey}`;
        parameters[parameterKey] = condition.value;
        break;
      case "gt":
        query += ` > :${parameterKey}`;
        parameters[parameterKey] = condition.value;
        break;
      case "gte":
        query += ` >= :${parameterKey}`;
        parameters[parameterKey] = condition.value;
        break;
      case "in":
        query += ` IN (:...${parameterKey})`;
        parameters[parameterKey] = condition.value;
        break;
      case "notIn":
        query += ` NOT IN (:...${parameterKey})`;
        parameters[parameterKey] = condition.value;
        break;
      case "between":
        query += ` BETWEEN :${parameterKey}_start AND :${parameterKey}_end`;
        parameters[`${parameterKey}_start`] = (condition.value as { start: any }).start;
        parameters[`${parameterKey}_end`] = (condition.value as { end: any }).end;
        break;
      case "null":
        query += ` IS NULL`;
        break;
      case "notNull":
        query += ` IS NOT NULL`;
        break;
      case "contains":
        query += ` LIKE :${parameterKey}`;
        parameters[parameterKey] = `%${condition.value}%`;
        break;
      case "notContains":
        query += ` NOT LIKE :${parameterKey}`;
        parameters[parameterKey] = `%${condition.value}%`;
        break;
      case "startsWith":
        query += ` LIKE :${parameterKey}`;
        parameters[parameterKey] = `${condition.value}%`;
        break;
      case "endsWith":
        query += ` LIKE :${parameterKey}`;
        parameters[parameterKey] = `%${condition.value}`;
        break;
      default:
        throw new Error(`Unsupported operation: ${condition.operation}`);
    }

    return { query, parameters };
  }

  // Helper: Convert nested conditions to a query
  public static conditionsToQuery(
    conditions: Array<ConditionStructure>,
    alias: string
  ): { query: string; parameters: Record<string, unknown> } {
    let queryParts: string[] = [];
    let parameters: Record<string, unknown> = {};

    conditions.forEach((condition, index) => {
      if (condition.structureType === "condition") {
        const clause = this.buildConditionClause(condition, alias);
        queryParts.push(clause.query);
        parameters = { ...parameters, ...clause.parameters };
      } else if (condition.structureType === "nested") {
        const nested = this.conditionsToQuery(condition.condition, alias);
        queryParts.push(`(${nested.query})`);
        parameters = { ...parameters, ...nested.parameters };
      }
    });

    return { query: queryParts.join(" AND "), parameters };
  }

  // use switch... for compare functions
  // use NotBrackets/Brackets for nested conditions
  // use joins by requesting table schema and setting correct column
}