import { Dayjs, isDayjs } from "dayjs";
import pako from "pako";
import { compressString, decompressString } from "./compression";
import { Condition } from "./Condition";
import { CreateTableAsSelect } from "./CreateTableAsSelect";
import { CreateViewAsSelect } from "./CreateViewAsSelect";
import {
  Expression,
  ExpressionBase,
  ExpressionRawValue,
  ExpressionValue,
  RawExpression,
} from "./Expression";
import { ISQLFlavor } from "./Flavor";
import { AWSTimestreamFlavor } from "./flavors/aws-timestream";
import { MySQLFlavor } from "./flavors/mysql";
import { PostgresFlavor } from "./flavors/postgres";
import { SQLiteFlavor } from "./flavors/sqlite";
import { Fn } from "./Function";
import {
  ICompilable,
  IMetadata,
  IQueryTarget,
  ISequelizable,
  ISequelizableOptions,
  ISerializable,
  ISerializableOptions,
  MetadataOperationType,
  OperationType,
} from "./interfaces";
import { DeleteMutation, InsertMutation, UpdateMutation } from "./Mutation";

export type InputValue = ExpressionValue | Dayjs | null;

const flavors = {
  mysql: new MySQLFlavor(),
  awsTimestream: new AWSTimestreamFlavor(),
  sqlite: new SQLiteFlavor(),
  postgres: new PostgresFlavor(),
};

export type TableSource =
  | string
  | SelectQuery
  | CreateTableAsSelect
  | CreateViewAsSelect;

function isTableReference(
  table: TableSource
): table is CreateTableAsSelect | CreateViewAsSelect {
  return (
    table instanceof CreateTableAsSelect || table instanceof CreateViewAsSelect
  );
}

function getTableReferenceName(
  table: CreateTableAsSelect | CreateViewAsSelect
): string {
  return table instanceof CreateTableAsSelect
    ? table.getTableName()
    : table.getViewName();
}

export class Table implements ISequelizable, ISerializable {
  public source: string | SelectQuery;
  public alias?: string;

  constructor(source: TableSource, alias?: string) {
    // Normalize CTAS/CVAS to plain string table names
    if (isTableReference(source)) {
      this.source = getTableReferenceName(source);
    } else {
      this.source = source;
    }
    this.alias = alias;
  }
  public clone(): this {
    return new (this.constructor as any)(this.source, this.alias);
  }
  public getTableName(): string | undefined {
    if (typeof this.source === "string") {
      return this.source;
    }
    return this.source.table?.getTableName();
  }

  toSQL(flavor: ISQLFlavor, options?: ISequelizableOptions): string {
    let table: string | SelectQuery = this.source;

    if (!isSelectQuery(table) && options?.transformTable) {
      const transformed = options.transformTable(table);
      table = isTableReference(transformed)
        ? getTableReferenceName(transformed)
        : transformed;
      options = { ...options, transformTable: undefined };
    }

    const isSelect = isSelectQuery(table);
    let alias = this.alias;
    const tableName = escapeTable(table, flavor, options);
    if (isSelect && !alias) alias = "t";
    return `${tableName}${alias ? ` AS ${flavor.escapeColumn(alias)}` : ""}`;
  }
  toJSON(): any {
    return {
      type: "Table",
      source: this.source,
      alias: this.alias,
    };
  }
  static fromJSON(json: any): Table {
    if (
      typeof json.source === "object" &&
      json.source["type"] === OperationType.SELECT
    ) {
      return new Table(SelectQuery.fromJSON(json.source), json.alias);
    }
    return new Table(json.source, json.alias);
  }
  serialize(): string {
    return JSON.stringify(this.toJSON());
  }
  static deserialize(json: string): Table {
    return Table.fromJSON(JSON.parse(json));
  }
}

function isSelectQuery(table: TableSource): table is SelectQuery {
  return table instanceof SelectQuery;
}
export const escapeTable = (
  table: TableSource,
  flavor: ISQLFlavor,
  options?: ISequelizableOptions
): string => {
  if (isSelectQuery(table)) return `(${table.toSQL(flavor, options)})`;
  if (isTableReference(table)) return flavor.escapeTable(getTableReferenceName(table));
  return flavor.escapeTable(table);
};

export class QueryBase implements ISequelizable, IMetadata {
  protected _tables: Table[] = [];
  protected _joins?: Join[] = [];

  public getOperationType(): MetadataOperationType {
    return MetadataOperationType.SELECT;
  }

  // @ts-ignore
  public get table(): Table | undefined {
    if (this._tables.length === 0) return undefined;
    return this._tables[0];
  }
  public get tables(): Table[] {
    return this._tables;
  }
  public from(table: TableSource, alias?: string): this {
    const clone = this.clone();
    if (isSelectQuery(table)) {
      clone._tables = [new Table(table.clone(), alias)];
    } else {
      clone._tables = [new Table(table, alias)];
    }
    return clone;
  }

  public getTableNames(): string[] {
    return [
      ...this._tables.map((t) => t.getTableName()).filter((x) => x),
      ...this._joins.map((j) => j.getTableName()).filter((x) => x),
    ];
  }

  /**
   * join function to join tables with all join types
   */
  join(table: Table, condition?: Condition, type: JoinType = "INNER"): this {
    const clone = this.clone();
    clone._joins.push(new Join(table, condition, type));
    return clone;
  }
  innerJoin(table: Table, condition: Condition): this {
    return this.join(table, condition, "INNER");
  }
  leftJoin(table: Table, condition: Condition): this {
    return this.join(table, condition, "LEFT");
  }
  rightJoin(table: Table, condition: Condition): this {
    return this.join(table, condition, "RIGHT");
  }
  fullJoin(table: Table, condition: Condition): this {
    return this.join(table, condition, "FULL");
  }
  crossJoin(table: Table, condition: Condition): this {
    return this.join(table, condition, "CROSS");
  }

  public clone(): this {
    const clone = new (this.constructor as any)();
    clone._tables = [...this._tables.map((t) => t.clone())];
    clone._joins = [...this._joins.map((j) => j.clone())];
    return clone;
  }

  toSQL(flavor: ISQLFlavor, options?: ISequelizableOptions): string {
    return this.tables.length > 0
      ? `FROM ${this.tables
          .map((table) => table.toSQL(flavor, options))
          .join(",")}`
      : "";
  }
}

export type JoinType = "INNER" | "LEFT" | "RIGHT" | "FULL" | "CROSS";

export class Join {
  protected _type: JoinType;
  protected _table: Table;
  protected _condition?: Condition;

  constructor(table: Table, condition?: Condition, type: JoinType = "INNER") {
    this._table = table;
    this._condition = condition;
    this._type = type;
  }

  // AST getters for targets
  public getType(): JoinType {
    return this._type;
  }
  public getTable(): Table {
    return this._table;
  }
  public getCondition(): Condition | undefined {
    return this._condition;
  }

  public clone(): this {
    const clone = new (this.constructor as any)(
      this._table,
      this._condition,
      this._type
    );
    return clone;
  }

  public getTableName(): string {
    return this._table.getTableName();
  }

  toSQL(flavor: ISQLFlavor, options?: ISequelizableOptions): string {
    return `${this._type} JOIN ${this._table.toSQL(flavor, options)}${
      this._condition ? ` ON ${this._condition.toSQL(flavor)}` : ""
    }`;
  }

  toJSON(): any {
    return {
      type: "Join",
      table: this._table.toJSON(),
      condition: this._condition?.toJSON(),
      joinType: this._type,
    };
  }
  static fromJSON(json: any): Join {
    return new Join(
      Table.fromJSON(json.table),
      json.condition && Condition.fromJSON(json.condition),
      json.joinType
    );
  }
  serialize(): string {
    return JSON.stringify(this.toJSON());
  }
  static deserialize(json: string): Join {
    return Join.fromJSON(JSON.parse(json));
  }
}

export interface SelectField {
  name: ExpressionValue;
  alias?: string;
}

export interface OrderClause {
  field: ExpressionBase;
  direction: "ASC" | "DESC";
}

// Alias for backward compatibility
type Order = OrderClause;

class SelectBaseQuery extends QueryBase {
  protected _fields: SelectField[] = [];

  // AST getter for targets
  public getFields(): SelectField[] {
    return this._fields;
  }

  public clone(): this {
    const clone = super.clone();
    clone._fields = [...this._fields];
    return clone;
  }

  // @deprecated please use addField
  field(name: ExpressionValue, alias?: string): this {
    return this.addFields([{ name, alias }]);
  }
  // add single field
  addField(name: ExpressionValue, alias?: string): this {
    return this.addFields([{ name, alias }]);
  }
  // add multiple fields
  addFields(fields: SelectField[]): this {
    const clone = this.clone();
    clone._fields.push(
      ...fields.map((f) => ({
        name: Expression.deserialize(f.name),
        alias: f.alias,
      }))
    );
    return clone;
  }
  removeFields(): this {
    return this.fields([]);
  }
  // reset fields
  fields(fields: SelectField[]): this {
    const clone = this.clone();
    clone._fields = [];
    return clone.addFields(fields);
  }

  toSQL(flavor: ISQLFlavor, options?: ISequelizableOptions): string {
    const columns =
      this._fields.length > 0
        ? this._fields
            .map(
              (f) =>
                `${Expression.deserialize(f.name).toSQL(flavor, options)}${
                  f.alias ? ` AS ${flavor.escapeColumn(f.alias)}` : ""
                }`
            )
            .join(", ")
        : "*";
    return `SELECT ${columns} ${super.toSQL(flavor, options)}`;
  }
}

export enum UnionType {
  UNION = "UNION",
  UNION_ALL = "UNION ALL",
}

export class SelectQuery extends SelectBaseQuery implements ISerializable, ICompilable {
  protected _where: Condition[] = [];
  protected _having: Condition[] = [];
  protected _limit?: number;
  protected _offset?: number;
  protected _orderBy: Order[] = [];
  protected _groupBy: ExpressionBase[] = [];
  protected _unionQueries: { query: SelectQuery; type: UnionType }[] = [];

  public clone(): this {
    const clone = super.clone();
    clone._where = [...this._where];
    clone._having = [...this._having];
    clone._limit = this._limit;
    clone._offset = this._offset;
    clone._orderBy = [...this._orderBy];
    clone._groupBy = [...this._groupBy];
    clone._unionQueries = this._unionQueries.map((u) => ({
      query: u.query.clone(),
      type: u.type,
    }));
    return clone;
  }

  // AST getters for targets
  public getWhere(): Condition[] {
    return this._where;
  }
  public getHaving(): Condition[] {
    return this._having;
  }
  public getJoins(): Join[] {
    return this._joins;
  }
  public getUnionQueries(): { query: SelectQuery; type: UnionType }[] {
    return this._unionQueries;
  }

  where(condition: Condition | null): this {
    if (condition === null) return this;
    const clone = this.clone();
    clone._where.push(condition);
    return clone;
  }
  removeWhere(): this {
    const clone = this.clone();
    clone._where = [];
    return clone;
  }
  having(condition: Condition): this {
    const clone = this.clone();
    clone._having.push(condition);
    return clone;
  }
  removeHaving(): this {
    const clone = this.clone();
    clone._having = [];
    return clone;
  }

  public getLimit(): number | undefined {
    return this._limit;
  }
  clearLimit(): this {
    const clone = this.clone();
    clone._limit = undefined;
    return clone;
  }
  limit(limit: number): this {
    const clone = this.clone();
    clone._limit = limit;
    return clone;
  }

  public getOffset(): number | undefined {
    return this._offset;
  }
  clearOffset(): this {
    const clone = this.clone();
    clone._offset = undefined;
    return clone;
  }
  offset(offset: number): SelectQuery {
    const clone = this.clone();
    clone._offset = offset;
    return clone;
  }
  public getOrderBy(): Order[] {
    return this._orderBy;
  }
  orderBy(field: ExpressionValue, direction: "ASC" | "DESC" = "ASC"): this {
    const clone = this.clone();
    clone._orderBy.push({
      field: Expression.deserialize(field),
      direction,
    });
    return clone;
  }
  removeOrderBy(): this {
    const clone = this.clone();
    clone._orderBy = [];
    return clone;
  }
  public getGroupBy(): ExpressionBase[] {
    return this._groupBy;
  }
  groupBy(...field: ExpressionValue[]): this {
    const clone = this.clone();
    clone._groupBy.push(...field.map((f) => Expression.deserialize(f)));
    return clone;
  }
  removeGroupBy(): this {
    const clone = this.clone();
    clone._groupBy = [];
    return clone;
  }
  public union(query: SelectQuery, type: UnionType = UnionType.UNION): this {
    const clone = this.clone();
    clone._unionQueries.push({ query, type });
    return clone;
  }

  public getTableNames(): string[] {
    return Array.from(
      new Set([
        ...super.getTableNames(),
        ...this._unionQueries.reduce(
          (acc, u) => [...acc, ...u.query.getTableNames()],
          [] as string[]
        ),
      ])
    );
  }

  toSQL(
    flavor: ISQLFlavor = flavors.mysql,
    options?: ISequelizableOptions,
    transformProcessed = false
  ): string {
    let sql = "";
    if (options?.transformSelectQuery && !transformProcessed) {
      const q = options.transformSelectQuery(this);
      return q.toSQL(flavor, options, true);
    } else {
      sql = super.toSQL(flavor, options);
    }

    if (this._joins?.length > 0) {
      sql += ` ${this._joins.map((j) => j.toSQL(flavor, options)).join(" ")}`;
    }
    if (this._where.length > 0) {
      sql += ` WHERE ${this._where.map((w) => w.toSQL(flavor)).join(" AND ")}`;
    }
    if (this._groupBy.length > 0) {
      sql += ` GROUP BY ${this._groupBy
        .map((c) => c.toSQL(flavor))
        .join(", ")}`;
    }
    if (this._having.length > 0) {
      sql += ` HAVING ${this._having
        .map((w) => w.toSQL(flavor))
        .join(" AND ")}`;
    }
    if (this._orderBy.length > 0) {
      sql += ` ORDER BY ${this._orderBy
        .map((o) => `${o.field.toSQL(flavor)} ${o.direction}`)
        .join(", ")}`;
    }

    sql += flavor.escapeLimitAndOffset(this._limit, this._offset);

    this._unionQueries.forEach((unionQuery) => {
      sql = flavor.escapeUnion(
        unionQuery.type,
        sql,
        unionQuery.query.toSQL(flavor, options)
      );
    });
    return sql;
  }

  /**
   * Compile this query using the provided target.
   * @param target The query target to use for compilation
   * @returns The compiled output in the target's format
   */
  compile<T>(target: IQueryTarget<T>): T {
    return target.compileSelect(this);
  }

  // serialization
  serialize(opts: ISerializableOptions = { compress: false }): string {
    const json = JSON.stringify(this.toJSON());
    return opts.compress ? compressString(json) : json;
  }
  toJSON(): any {
    return {
      type: OperationType.SELECT,
      tables: this._tables.map((table) =>
        typeof table === "string" ? table : table.toJSON()
      ),
      unionQueries:
        this._unionQueries.length > 0
          ? this._unionQueries.map((u) => ({
              type: u.type,
              query: u.query.toJSON(),
            }))
          : undefined,
      joins:
        this._joins.length > 0
          ? this._joins.map((join) => join.toJSON())
          : undefined,
      fields:
        this._fields.length > 0
          ? this._fields.map((f) => ({
              name: Expression.deserialize(f.name).serialize(),
              alias: f.alias,
            }))
          : undefined,
      where:
        this._where.length > 0
          ? this._where.map((condition) => condition.toJSON())
          : undefined,
      having:
        this._having.length > 0
          ? this._having.map((condition) => condition.toJSON())
          : undefined,
      orderBy:
        this._orderBy.length > 0
          ? this._orderBy.map((o) => ({
              field: o.field.serialize(),
              direction: o.direction,
            }))
          : undefined,
      groupBy:
        this._groupBy.length > 0
          ? this._groupBy.map((c) => c.serialize())
          : undefined,
      limit: this._limit,
      offset: this._offset,
    };
  }
  static fromJSON(json: any): SelectQuery {
    const query = new SelectQuery();
    query._tables = json.tables.map((table: any) => {
      return Table.fromJSON(table);
    });
    query._unionQueries = (json.unionQueries || []).map((u: any) => ({
      type: u.type,
      query: SelectQuery.fromJSON(u.query),
    }));
    query._joins = (json.joins || []).map((joinJson: any) =>
      Join.fromJSON(joinJson)
    );
    query._fields = (json.fields ?? []).map((field: any) => ({
      name: Expression.deserialize(field.name),
      alias: field.alias,
    }));
    query._where = (json.where || []).map((conditionJson: any) =>
      Condition.fromJSON(conditionJson)
    );
    query._having = (json.having || []).map((conditionJson: any) =>
      Condition.fromJSON(conditionJson)
    );
    query._limit = json.limit;
    query._offset = json.offset;
    query._orderBy = (json.orderBy ?? []).map((o: any) => ({
      field: Expression.deserialize(o.field),
      direction: o.direction,
    }));
    query._groupBy = (json.groupBy ?? []).map((v) => Expression.deserialize(v));
    return query;
  }
}

const deserialize = (payload: string) => {
  try {
    const parsed =
      payload[0] === "{"
        ? JSON.parse(payload)
        : JSON.parse(decompressString(payload));

    switch (parsed.type as OperationType) {
      case OperationType.SELECT:
        return SelectQuery.fromJSON(parsed);
      case OperationType.DELETE:
        return DeleteMutation.fromJSON(parsed);
      case OperationType.INSERT:
        return InsertMutation.fromJSON(parsed);
      case OperationType.UPDATE:
        return UpdateMutation.fromJSON(parsed);
      case OperationType.CREATE_TABLE_AS:
        return CreateTableAsSelect.fromJSON(parsed);
      case OperationType.CREATE_VIEW_AS:
        return CreateViewAsSelect.fromJSON(parsed);
      default:
        throw new Error("Unknown mutation type");
    }
  } catch (e) {
    throw new Error(`Error parsing query: ${(e as Error).message}`);
  }
};

const deserializeRaw = (json: string) => {
  try {
    return deserialize(json);
  } catch (e) {
    return Expression.deserialize(json);
  }
};

const inputValueToExpressionValue = (val: InputValue): ExpressionValue => {
  if (isDayjs(val)) return val.toDate();
  return val;
};

const values = (data: Record<string, any>[]): SelectQuery => {
  if (data.length === 0)
    throw new Error("values requires at least one row");
  const columns = Object.keys(data[0]);

  // First row: SELECT val AS col1, val AS col2, ...
  let result = new SelectQuery();
  for (const col of columns) {
    const val = data[0][col];
    result = result.addField(
      val === null || val === undefined
        ? new RawExpression("NULL")
        : ExpressionBase.deserializeValue(val),
      col
    );
  }

  // Remaining rows: UNION ALL SELECT val, val, ...
  for (let i = 1; i < data.length; i++) {
    let rowQuery = new SelectQuery();
    for (const col of columns) {
      const val = data[i][col];
      rowQuery = rowQuery.addField(
        val === null || val === undefined
          ? new RawExpression("NULL")
          : ExpressionBase.deserializeValue(val)
      );
    }
    result = result.union(rowQuery, UnionType.UNION_ALL);
  }

  return result;
};

export const Query = {
  table: (source: TableSource, alias?: string) => new Table(source, alias),
  select: () => {
    return new SelectQuery();
  },
  stats: () => new SelectQuery().from("(?)", "t"),
  delete: (from: string, alias?: string) => new DeleteMutation(from, alias),
  update: (table: string, alias?: string) => new UpdateMutation(table, alias),
  insert: (into: string) => new InsertMutation(into),
  createTableAs: (table: string, select: SelectQuery) =>
    new CreateTableAsSelect(table, select),
  createOrReplaceTableAs: (table: string, select: SelectQuery) =>
    new CreateTableAsSelect(table, select, true),
  createTableIfNotExistsAs: (table: string, select: SelectQuery) =>
    new CreateTableAsSelect(table, select, false, true),
  createViewAs: (table: string, select: SelectQuery) =>
    new CreateViewAsSelect(table, select),
  createOrReplaceViewAs: (table: string, select: SelectQuery) =>
    new CreateViewAsSelect(table, select, true),
  values,
  deserialize,
  deserializeRaw,
  flavors,
  null: () => new RawExpression("NULL"),
  raw: (val: ExpressionRawValue) => new RawExpression(val),
  expr: (val: InputValue) =>
    ExpressionBase.deserialize(inputValueToExpressionValue(val)),
  exprValue: (val: InputValue) =>
    ExpressionBase.deserializeValue(inputValueToExpressionValue(val)),
  value: (val: InputValue) =>
    ExpressionBase.deserializeValue(inputValueToExpressionValue(val)),
  column: (col: ExpressionRawValue) => Expression.escapeColumn(col),
  S: (literals: string | readonly string[]) => {
    return Fn.string(`${literals}`);
  },
  string: (literals: string | readonly string[]) => {
    return Fn.string(`${literals}`);
  },
};

// for shorter syntax
export { Query as Q };