import { PostgresConnectionOptions } from "../driver/postgres/PostgresConnectionOptions"
import { Query } from "../driver/Query"
import { SqlInMemory } from "../driver/SqlInMemory"
import { SqlServerConnectionOptions } from "../driver/sqlserver/SqlServerConnectionOptions"
import { TableIndex } from "../schema-builder/table/TableIndex"
import { View } from "../schema-builder/view/View"
import { DataSource } from "../data-source/DataSource"
import { Table } from "../schema-builder/table/Table"
import { EntityManager } from "../entity-manager/EntityManager"
import { TableColumn } from "../schema-builder/table/TableColumn"
import { Broadcaster } from "../subscriber/Broadcaster"
import { ReplicationMode } from "../driver/types/ReplicationMode"
import { TypeORMError } from "../error/TypeORMError"
import { EntityMetadata } from "../metadata/EntityMetadata"
import { TableForeignKey } from "../schema-builder/table/TableForeignKey"
import { OrmUtils } from "../util/OrmUtils"
import { MetadataTableType } from "../driver/types/MetadataTableType"
import { InstanceChecker } from "../util/InstanceChecker"

export abstract class BaseQueryRunner {
    // -------------------------------------------------------------------------
    // Public Properties
    // -------------------------------------------------------------------------

    /**
     * Connection used by this query runner.
     */
    connection: DataSource

    /**
     * Entity manager working only with current query runner.
     */
    manager: EntityManager

    /**
     * Indicates if connection for this query runner is released.
     * Once its released, query runner cannot run queries anymore.
     */
    isReleased = false

    /**
     * Indicates if transaction is in progress.
     */
    isTransactionActive = false

    /**
     * Stores temporarily user data.
     * Useful for sharing data with subscribers.
     */
    data = {}

    /**
     * All synchronized tables in the database.
     */
    loadedTables: Table[] = []

    /**
     * All synchronized views in the database.
     */
    loadedViews: View[] = []

    /**
     * Broadcaster used on this query runner to broadcast entity events.
     */
    broadcaster: Broadcaster

    // -------------------------------------------------------------------------
    // Protected Properties
    // -------------------------------------------------------------------------

    /**
     * Real database connection from a connection pool used to perform queries.
     */
    protected databaseConnection: any

    /**
     * Indicates if special query runner mode in which sql queries won't be executed is enabled.
     */
    protected sqlMemoryMode: boolean = false

    /**
     * Sql-s stored if "sql in memory" mode is enabled.
     */
    protected sqlInMemory: SqlInMemory = new SqlInMemory()

    /**
     * Mode in which query runner executes.
     * Used for replication.
     * If replication is not setup its value is ignored.
     */
    protected mode: ReplicationMode

    /**
     * current depth of transaction.
     * for transactionDepth > 0 will use SAVEPOINT to start and commit/rollback transaction blocks
     */
    protected transactionDepth = 0

    private cachedTablePaths: Record<string, string> = {}

    // -------------------------------------------------------------------------
    // Public Abstract Methods
    // -------------------------------------------------------------------------

    /**
     * Executes a given SQL query.
     */
    abstract query(
        query: string,
        parameters?: any[],
        useStructuredResult?: boolean,
    ): Promise<any>

    // -------------------------------------------------------------------------
    // Protected Abstract Methods
    // -------------------------------------------------------------------------

    protected abstract loadTables(tablePaths?: string[]): Promise<Table[]>

    protected abstract loadViews(tablePaths?: string[]): Promise<View[]>

    // -------------------------------------------------------------------------
    // Public Methods
    // -------------------------------------------------------------------------

    /**
     * Called before migrations are run.
     */
    async beforeMigration(): Promise<void> {
        // Do nothing
    }

    /**
     * Called after migrations are run.
     */
    async afterMigration(): Promise<void> {
        // Do nothing
    }

    /**
     * Loads given table's data from the database.
     */
    async getTable(tablePath: string): Promise<Table | undefined> {
        this.loadedTables = await this.loadTables([tablePath])
        return this.loadedTables.length > 0 ? this.loadedTables[0] : undefined
    }

    /**
     * Loads all tables (with given names) from the database.
     */
    async getTables(tableNames?: string[]): Promise<Table[]> {
        if (!tableNames) {
            // Don't cache in this case.
            // This is the new case & isn't used anywhere else anyway.
            return await this.loadTables(tableNames)
        }

        this.loadedTables = await this.loadTables(tableNames)
        return this.loadedTables
    }

    /**
     * Loads given view's data from the database.
     */
    async getView(viewPath: string): Promise<View | undefined> {
        this.loadedViews = await this.loadViews([viewPath])
        return this.loadedViews.length > 0 ? this.loadedViews[0] : undefined
    }

    /**
     * Loads given view's data from the database.
     */
    async getViews(viewPaths?: string[]): Promise<View[]> {
        this.loadedViews = await this.loadViews(viewPaths)
        return this.loadedViews
    }

    /**
     * Enables special query runner mode in which sql queries won't be executed,
     * instead they will be memorized into a special variable inside query runner.
     * You can get memorized sql using getMemorySql() method.
     */
    enableSqlMemory(): void {
        this.sqlInMemory = new SqlInMemory()
        this.sqlMemoryMode = true
    }

    /**
     * Disables special query runner mode in which sql queries won't be executed
     * started by calling enableSqlMemory() method.
     *
     * Previously memorized sql will be flushed.
     */
    disableSqlMemory(): void {
        this.sqlInMemory = new SqlInMemory()
        this.sqlMemoryMode = false
    }

    /**
     * Flushes all memorized sqls.
     */
    clearSqlMemory(): void {
        this.sqlInMemory = new SqlInMemory()
    }

    /**
     * Gets sql stored in the memory. Parameters in the sql are already replaced.
     */
    getMemorySql(): SqlInMemory {
        return this.sqlInMemory
    }

    /**
     * Executes up sql queries.
     */
    async executeMemoryUpSql(): Promise<void> {
        for (const { query, parameters } of this.sqlInMemory.upQueries) {
            await this.query(query, parameters)
        }
    }

    /**
     * Executes down sql queries.
     */
    async executeMemoryDownSql(): Promise<void> {
        for (const {
            query,
            parameters,
        } of this.sqlInMemory.downQueries.reverse()) {
            await this.query(query, parameters)
        }
    }

    getReplicationMode(): ReplicationMode {
        return this.mode
    }

    // -------------------------------------------------------------------------
    // Protected Methods
    // -------------------------------------------------------------------------

    /**
     * Gets view from previously loaded views, otherwise loads it from database.
     */
    protected async getCachedView(viewName: string): Promise<View> {
        const view = this.loadedViews.find((view) => view.name === viewName)
        if (view) return view

        const foundViews = await this.loadViews([viewName])
        if (foundViews.length > 0) {
            this.loadedViews.push(foundViews[0])
            return foundViews[0]
        } else {
            throw new TypeORMError(`View "${viewName}" does not exist.`)
        }
    }

    /**
     * Gets table from previously loaded tables, otherwise loads it from database.
     */
    protected async getCachedTable(tableName: string): Promise<Table> {
        if (tableName in this.cachedTablePaths) {
            const tablePath = this.cachedTablePaths[tableName]
            const table = this.loadedTables.find(
                (table) => this.getTablePath(table) === tablePath,
            )

            if (table) {
                return table
            }
        }

        const foundTables = await this.loadTables([tableName])

        if (foundTables.length > 0) {
            const foundTablePath = this.getTablePath(foundTables[0])

            const cachedTable = this.loadedTables.find(
                (table) => this.getTablePath(table) === foundTablePath,
            )

            if (!cachedTable) {
                this.cachedTablePaths[tableName] = this.getTablePath(
                    foundTables[0],
                )
                this.loadedTables.push(foundTables[0])
                return foundTables[0]
            } else {
                return cachedTable
            }
        } else {
            throw new TypeORMError(`Table "${tableName}" does not exist.`)
        }
    }

    /**
     * Replaces loaded table with given changed table.
     */
    protected replaceCachedTable(table: Table, changedTable: Table): void {
        const oldTablePath = this.getTablePath(table)
        const foundTable = this.loadedTables.find(
            (loadedTable) => this.getTablePath(loadedTable) === oldTablePath,
        )

        // Clean up the lookup cache..
        for (const [key, cachedPath] of Object.entries(this.cachedTablePaths)) {
            if (cachedPath === oldTablePath) {
                this.cachedTablePaths[key] = this.getTablePath(changedTable)
            }
        }

        if (foundTable) {
            foundTable.database = changedTable.database
            foundTable.schema = changedTable.schema
            foundTable.name = changedTable.name
            foundTable.columns = changedTable.columns
            foundTable.indices = changedTable.indices
            foundTable.foreignKeys = changedTable.foreignKeys
            foundTable.uniques = changedTable.uniques
            foundTable.checks = changedTable.checks
            foundTable.justCreated = changedTable.justCreated
            foundTable.engine = changedTable.engine
        }
    }

    protected getTablePath(
        target: EntityMetadata | Table | View | TableForeignKey | string,
    ): string {
        const parsed = this.connection.driver.parseTableName(target)

        return this.connection.driver.buildTableName(
            parsed.tableName,
            parsed.schema,
            parsed.database,
        )
    }

    protected getTypeormMetadataTableName(): string {
        const options = <
            SqlServerConnectionOptions | PostgresConnectionOptions
        >this.connection.driver.options
        return this.connection.driver.buildTableName(
            this.connection.metadataTableName,
            options.schema,
            options.database,
        )
    }

    /**
     * Generates SQL query to select record from typeorm metadata table.
     */
    protected selectTypeormMetadataSql({
        database,
        schema,
        table,
        type,
        name,
    }: {
        database?: string
        schema?: string
        table?: string
        type: MetadataTableType
        name: string
    }): Query {
        const qb = this.connection.createQueryBuilder()
        const selectQb = qb
            .select()
            .from(this.getTypeormMetadataTableName(), "t")
            .where(`${qb.escape("type")} = :type`, { type })
            .andWhere(`${qb.escape("name")} = :name`, { name })

        if (database) {
            selectQb.andWhere(`${qb.escape("database")} = :database`, {
                database,
            })
        }

        if (schema) {
            selectQb.andWhere(`${qb.escape("schema")} = :schema`, { schema })
        }

        if (table) {
            selectQb.andWhere(`${qb.escape("table")} = :table`, { table })
        }

        const [query, parameters] = selectQb.getQueryAndParameters()
        return new Query(query, parameters)
    }

    /**
     * Generates SQL query to insert a record into typeorm metadata table.
     */
    protected insertTypeormMetadataSql({
        database,
        schema,
        table,
        type,
        name,
        value,
    }: {
        database?: string
        schema?: string
        table?: string
        type: MetadataTableType
        name: string
        value?: string
    }): Query {
        const [query, parameters] = this.connection
            .createQueryBuilder()
            .insert()
            .into(this.getTypeormMetadataTableName())
            .values({
                database: database,
                schema: schema,
                table: table,
                type: type,
                name: name,
                value: value,
            })
            .getQueryAndParameters()

        return new Query(query, parameters)
    }

    /**
     * Generates SQL query to delete a record from typeorm metadata table.
     */
    protected deleteTypeormMetadataSql({
        database,
        schema,
        table,
        type,
        name,
    }: {
        database?: string
        schema?: string
        table?: string
        type: MetadataTableType
        name: string
    }): Query {
        const qb = this.connection.createQueryBuilder()
        const deleteQb = qb
            .delete()
            .from(this.getTypeormMetadataTableName())
            .where(`${qb.escape("type")} = :type`, { type })
            .andWhere(`${qb.escape("name")} = :name`, { name })

        if (database) {
            deleteQb.andWhere(`${qb.escape("database")} = :database`, {
                database,
            })
        }

        if (schema) {
            deleteQb.andWhere(`${qb.escape("schema")} = :schema`, { schema })
        }

        if (table) {
            deleteQb.andWhere(`${qb.escape("table")} = :table`, { table })
        }

        const [query, parameters] = deleteQb.getQueryAndParameters()
        return new Query(query, parameters)
    }

    /**
     * Checks if at least one of column properties was changed.
     * Does not checks column type, length and autoincrement, because these properties changes separately.
     */
    protected isColumnChanged(
        oldColumn: TableColumn,
        newColumn: TableColumn,
        checkDefault?: boolean,
        checkComment?: boolean,
        checkEnum = true,
    ): boolean {
        // this logs need to debug issues in column change detection. Do not delete it!

        // console.log("charset ---------------");
        // console.log(oldColumn.charset !== newColumn.charset);
        // console.log(oldColumn.charset, newColumn.charset);
        // console.log("collation ---------------");
        // console.log(oldColumn.collation !== newColumn.collation);
        // console.log(oldColumn.collation, newColumn.collation);
        // console.log("precision ---------------");
        // console.log(oldColumn.precision !== newColumn.precision);
        // console.log(oldColumn.precision, newColumn.precision);
        // console.log("scale ---------------");
        // console.log(oldColumn.scale !== newColumn.scale);
        // console.log(oldColumn.scale, newColumn.scale);
        // console.log("default ---------------");
        // console.log((checkDefault && oldColumn.default !== newColumn.default));
        // console.log(oldColumn.default, newColumn.default);
        // console.log("isNullable ---------------");
        // console.log(oldColumn.isNullable !== newColumn.isNullable);
        // console.log(oldColumn.isNullable, newColumn.isNullable);
        // console.log("comment ---------------");
        // console.log((checkComment && oldColumn.comment !== newColumn.comment));
        // console.log(oldColumn.comment, newColumn.comment);
        // console.log("enum ---------------");
        // console.log(!OrmUtils.isArraysEqual(oldColumn.enum || [], newColumn.enum || []));
        // console.log(oldColumn.enum, newColumn.enum);

        return (
            oldColumn.charset !== newColumn.charset ||
            oldColumn.collation !== newColumn.collation ||
            oldColumn.precision !== newColumn.precision ||
            oldColumn.scale !== newColumn.scale ||
            oldColumn.width !== newColumn.width || // MySQL only
            oldColumn.zerofill !== newColumn.zerofill || // MySQL only
            oldColumn.unsigned !== newColumn.unsigned || // MySQL only
            oldColumn.asExpression !== newColumn.asExpression ||
            (checkDefault && oldColumn.default !== newColumn.default) ||
            oldColumn.onUpdate !== newColumn.onUpdate || // MySQL only
            oldColumn.isNullable !== newColumn.isNullable ||
            (checkComment && oldColumn.comment !== newColumn.comment) ||
            (checkEnum && this.isEnumChanged(oldColumn, newColumn))
        )
    }

    protected isEnumChanged(oldColumn: TableColumn, newColumn: TableColumn) {
        return !OrmUtils.isArraysEqual(
            oldColumn.enum || [],
            newColumn.enum || [],
        )
    }

    /**
     * Checks if column length is by default.
     */
    protected isDefaultColumnLength(
        table: Table,
        column: TableColumn,
        length: string,
    ): boolean {
        // if table have metadata, we check if length is specified in column metadata
        if (this.connection.hasMetadata(table.name)) {
            const metadata = this.connection.getMetadata(table.name)
            const columnMetadata = metadata.findColumnWithDatabaseName(
                column.name,
            )

            if (columnMetadata) {
                const columnMetadataLength =
                    this.connection.driver.getColumnLength(columnMetadata)
                if (columnMetadataLength) return false
            }
        }

        if (
            this.connection.driver.dataTypeDefaults &&
            this.connection.driver.dataTypeDefaults[column.type] &&
            this.connection.driver.dataTypeDefaults[column.type].length
        ) {
            return (
                this.connection.driver.dataTypeDefaults[
                    column.type
                ].length!.toString() === length.toString()
            )
        }

        return false
    }

    /**
     * Checks if column precision is by default.
     */
    protected isDefaultColumnPrecision(
        table: Table,
        column: TableColumn,
        precision: number,
    ): boolean {
        // if table have metadata, we check if length is specified in column metadata
        if (this.connection.hasMetadata(table.name)) {
            const metadata = this.connection.getMetadata(table.name)
            const columnMetadata = metadata.findColumnWithDatabaseName(
                column.name,
            )
            if (
                columnMetadata &&
                columnMetadata.precision !== null &&
                columnMetadata.precision !== undefined
            )
                return false
        }

        if (
            this.connection.driver.dataTypeDefaults &&
            this.connection.driver.dataTypeDefaults[column.type] &&
            this.connection.driver.dataTypeDefaults[column.type].precision !==
                null &&
            this.connection.driver.dataTypeDefaults[column.type].precision !==
                undefined
        )
            return (
                this.connection.driver.dataTypeDefaults[column.type]
                    .precision === precision
            )

        return false
    }

    /**
     * Checks if column scale is by default.
     */
    protected isDefaultColumnScale(
        table: Table,
        column: TableColumn,
        scale: number,
    ): boolean {
        // if table have metadata, we check if length is specified in column metadata
        if (this.connection.hasMetadata(table.name)) {
            const metadata = this.connection.getMetadata(table.name)
            const columnMetadata = metadata.findColumnWithDatabaseName(
                column.name,
            )
            if (
                columnMetadata &&
                columnMetadata.scale !== null &&
                columnMetadata.scale !== undefined
            )
                return false
        }

        if (
            this.connection.driver.dataTypeDefaults &&
            this.connection.driver.dataTypeDefaults[column.type] &&
            this.connection.driver.dataTypeDefaults[column.type].scale !==
                null &&
            this.connection.driver.dataTypeDefaults[column.type].scale !==
                undefined
        )
            return (
                this.connection.driver.dataTypeDefaults[column.type].scale ===
                scale
            )

        return false
    }

    /**
     * Executes sql used special for schema build.
     */
    protected async executeQueries(
        upQueries: Query | Query[],
        downQueries: Query | Query[],
    ): Promise<void> {
        if (InstanceChecker.isQuery(upQueries)) upQueries = [upQueries]
        if (InstanceChecker.isQuery(downQueries)) downQueries = [downQueries]

        this.sqlInMemory.upQueries.push(...upQueries)
        this.sqlInMemory.downQueries.push(...downQueries)

        // if sql-in-memory mode is enabled then simply store sql in memory and return
        if (this.sqlMemoryMode === true)
            return Promise.resolve() as Promise<any>

        for (const { query, parameters } of upQueries) {
            await this.query(query, parameters)
        }
    }

    /**
     * Generated an index name for a table and index
     */
    protected generateIndexName(
        table: Table | View,
        index: TableIndex,
    ): string {
        // new index may be passed without name. In this case we generate index name manually.
        return this.connection.namingStrategy.indexName(
            table,
            index.columnNames,
            index.where,
        )
    }
}