import { EntityMetadata } from "../metadata/EntityMetadata"
import { MissingPrimaryColumnError } from "../error/MissingPrimaryColumnError"
import { CircularRelationsError } from "../error/CircularRelationsError"
import { DepGraph } from "../util/DepGraph"
import { Driver } from "../driver/Driver"
import { DataTypeNotSupportedError } from "../error/DataTypeNotSupportedError"
import { ColumnType } from "../driver/types/ColumnTypes"
import { NoConnectionOptionError } from "../error/NoConnectionOptionError"
import { InitializedRelationError } from "../error/InitializedRelationError"
import { TypeORMError } from "../error"
import { DriverUtils } from "../driver/DriverUtils"

/// todo: add check if there are multiple tables with the same name
/// todo: add checks when generated column / table names are too long for the specific driver
// todo: type in function validation, inverse side function validation
// todo: check on build for duplicate names, since naming checking was removed from MetadataStorage
// todo: duplicate name checking for: table, relation, column, index, naming strategy, join tables/columns?
// todo: check if multiple tree parent metadatas in validator
// todo: tree decorators can be used only on closure table (validation)
// todo: throw error if parent tree metadata was not specified in a closure table

// todo: MetadataArgsStorage: type in function validation, inverse side function validation
// todo: MetadataArgsStorage: check on build for duplicate names, since naming checking was removed from MetadataStorage
// todo: MetadataArgsStorage: duplicate name checking for: table, relation, column, index, naming strategy, join tables/columns?
// todo: MetadataArgsStorage: check for duplicate targets too since this check has been removed too
// todo: check if relation decorator contains primary: true and nullable: true
// todo: check column length, precision. scale
// todo: MySQL index can be unique or spatial or fulltext

/**
 * Validates built entity metadatas.
 */
export class EntityMetadataValidator {
    // -------------------------------------------------------------------------
    // Public Methods
    // -------------------------------------------------------------------------

    /**
     * Validates all given entity metadatas.
     */
    validateMany(entityMetadatas: EntityMetadata[], driver: Driver) {
        entityMetadatas.forEach((entityMetadata) =>
            this.validate(entityMetadata, entityMetadatas, driver),
        )
        this.validateDependencies(entityMetadatas)
        this.validateEagerRelations(entityMetadatas)
    }

    /**
     * Validates given entity metadata.
     */
    validate(
        entityMetadata: EntityMetadata,
        allEntityMetadatas: EntityMetadata[],
        driver: Driver,
    ) {
        // check if table metadata has an id
        if (!entityMetadata.primaryColumns.length && !entityMetadata.isJunction)
            throw new MissingPrimaryColumnError(entityMetadata)

        // if entity has multiple primary keys and uses custom constraint name,
        // then all primary keys should have the same constraint name
        if (entityMetadata.primaryColumns.length > 1) {
            const areConstraintNamesEqual = entityMetadata.primaryColumns.every(
                (columnMetadata, i, columnMetadatas) =>
                    columnMetadata.primaryKeyConstraintName ===
                    columnMetadatas[0].primaryKeyConstraintName,
            )
            if (!areConstraintNamesEqual) {
                throw new TypeORMError(
                    `Entity ${entityMetadata.name} has multiple primary columns with different constraint names. Constraint names should be the equal.`,
                )
            }
        }

        // validate if table is using inheritance it has a discriminator
        // also validate if discriminator values are not empty and not repeated
        if (
            entityMetadata.inheritancePattern === "STI" ||
            entityMetadata.tableType === "entity-child"
        ) {
            if (!entityMetadata.discriminatorColumn)
                throw new TypeORMError(
                    `Entity ${entityMetadata.name} using single-table inheritance, it should also have a discriminator column. Did you forget to put discriminator column options?`,
                )

            if (typeof entityMetadata.discriminatorValue === "undefined")
                throw new TypeORMError(
                    `Entity ${entityMetadata.name} has an undefined discriminator value. Discriminator value should be defined.`,
                )

            const sameDiscriminatorValueEntityMetadata =
                allEntityMetadatas.find((metadata) => {
                    return (
                        metadata !== entityMetadata &&
                        (metadata.inheritancePattern === "STI" ||
                            metadata.tableType === "entity-child") &&
                        metadata.tableName === entityMetadata.tableName &&
                        metadata.discriminatorValue ===
                            entityMetadata.discriminatorValue &&
                        metadata.inheritanceTree.some(
                            (parent) =>
                                entityMetadata.inheritanceTree.indexOf(
                                    parent,
                                ) !== -1,
                        )
                    )
                })
            if (sameDiscriminatorValueEntityMetadata)
                throw new TypeORMError(
                    `Entities ${entityMetadata.name} and ${sameDiscriminatorValueEntityMetadata.name} have the same discriminator values. Make sure they are different while using the @ChildEntity decorator.`,
                )
        }

        entityMetadata.relationCounts.forEach((relationCount) => {
            if (
                relationCount.relation.isManyToOne ||
                relationCount.relation.isOneToOne
            )
                throw new TypeORMError(
                    `Relation count can not be implemented on ManyToOne or OneToOne relations.`,
                )
        })

        if (!(driver.options.type === "mongodb")) {
            entityMetadata.columns
                .filter((column) => !column.isVirtualProperty)
                .forEach((column) => {
                    const normalizedColumn = driver.normalizeType(
                        column,
                    ) as ColumnType
                    if (
                        driver.supportedDataTypes.indexOf(normalizedColumn) ===
                        -1
                    )
                        throw new DataTypeNotSupportedError(
                            column,
                            normalizedColumn,
                            driver.options.type,
                        )
                    if (
                        column.length &&
                        driver.withLengthColumnTypes.indexOf(
                            normalizedColumn,
                        ) === -1
                    )
                        throw new TypeORMError(
                            `Column ${column.propertyName} of Entity ${entityMetadata.name} does not support length property.`,
                        )
                    if (
                        column.type === "enum" &&
                        !column.enum &&
                        !column.enumName
                    )
                        throw new TypeORMError(
                            `Column "${column.propertyName}" of Entity "${entityMetadata.name}" is defined as enum, but missing "enum" or "enumName" properties.`,
                        )
                })
        }

        if (
            DriverUtils.isMySQLFamily(driver) ||
            driver.options.type === "aurora-mysql"
        ) {
            const generatedColumns = entityMetadata.columns.filter(
                (column) =>
                    column.isGenerated && column.generationStrategy !== "uuid",
            )
            if (generatedColumns.length > 1)
                throw new TypeORMError(
                    `Error in ${entityMetadata.name} entity. There can be only one auto-increment column in MySql table.`,
                )
        }

        // for mysql we are able to not define a default selected database, instead all entities can have their database
        // defined in their decorators. To make everything work either all entities must have database define and we
        // can live without database set in the connection options, either database in the connection options must be set
        if (DriverUtils.isMySQLFamily(driver)) {
            const metadatasWithDatabase = allEntityMetadatas.filter(
                (metadata) => metadata.database,
            )
            if (metadatasWithDatabase.length === 0 && !driver.database)
                throw new NoConnectionOptionError("database")
        }

        if (driver.options.type === "mssql") {
            const charsetColumns = entityMetadata.columns.filter(
                (column) => column.charset,
            )
            if (charsetColumns.length > 1)
                throw new TypeORMError(
                    `Character set specifying is not supported in Sql Server`,
                )
        }

        // Postgres supports only STORED generated columns.
        if (driver.options.type === "postgres") {
            const virtualColumn = entityMetadata.columns.find(
                (column) =>
                    column.asExpression &&
                    (!column.generatedType ||
                        column.generatedType === "VIRTUAL"),
            )
            if (virtualColumn)
                throw new TypeORMError(
                    `Column "${virtualColumn.propertyName}" of Entity "${entityMetadata.name}" is defined as VIRTUAL, but Postgres supports only STORED generated columns.`,
                )
        }

        // check if relations are all without initialized properties
        const entityInstance = entityMetadata.create(undefined, {
            fromDeserializer: true,
        })
        entityMetadata.relations.forEach((relation) => {
            if (relation.isManyToMany || relation.isOneToMany) {
                // we skip relations for which persistence is disabled since initialization in them cannot harm somehow
                if (relation.persistenceEnabled === false) return

                // get entity relation value and check if its an array
                const relationInitializedValue =
                    relation.getEntityValue(entityInstance)
                if (Array.isArray(relationInitializedValue))
                    throw new InitializedRelationError(relation)
            }
        })

        // validate relations
        entityMetadata.relations.forEach((relation) => {
            // check OnDeleteTypes
            if (
                driver.supportedOnDeleteTypes &&
                relation.onDelete &&
                !driver.supportedOnDeleteTypes.includes(relation.onDelete)
            ) {
                throw new TypeORMError(
                    `OnDeleteType "${relation.onDelete}" is not supported for ${driver.options.type}!`,
                )
            }

            // check OnUpdateTypes
            if (
                driver.supportedOnUpdateTypes &&
                relation.onUpdate &&
                !driver.supportedOnUpdateTypes.includes(relation.onUpdate)
            ) {
                throw new TypeORMError(
                    `OnUpdateType "${relation.onUpdate}" is not valid for ${driver.options.type}!`,
                )
            }

            // check join tables:
            // using JoinTable is possible only on one side of the many-to-many relation
            // todo(dima): fix
            // if (relation.joinTable) {
            //     if (!relation.isManyToMany)
            //         throw new UsingJoinTableIsNotAllowedError(entityMetadata, relation);
            //     // if there is inverse side of the relation, then check if it does not have join table too
            //     if (relation.hasInverseSide && relation.inverseRelation.joinTable)
            //         throw new UsingJoinTableOnlyOnOneSideAllowedError(entityMetadata, relation);
            // }
            // check join columns:
            // using JoinColumn is possible only on one side of the relation and on one-to-one, many-to-one relation types
            // first check if relation is one-to-one or many-to-one
            // todo(dima): fix
            /*if (relation.joinColumn) {

                // join column can be applied only on one-to-one and many-to-one relations
                if (!relation.isOneToOne && !relation.isManyToOne)
                    throw new UsingJoinColumnIsNotAllowedError(entityMetadata, relation);

                // if there is inverse side of the relation, then check if it does not have join table too
                if (relation.hasInverseSide && relation.inverseRelation.joinColumn && relation.isOneToOne)
                    throw new UsingJoinColumnOnlyOnOneSideAllowedError(entityMetadata, relation);

                // check if join column really has referenced column
                if (relation.joinColumn && !relation.joinColumn.referencedColumn)
                    throw new TypeORMError(`Join column does not have referenced column set`);

            }

            // if its a one-to-one relation and JoinColumn is missing on both sides of the relation
            // or its one-side relation without JoinColumn we should give an error
            if (!relation.joinColumn && relation.isOneToOne && (!relation.hasInverseSide || !relation.inverseRelation.joinColumn))
                throw new MissingJoinColumnError(entityMetadata, relation);*/
            // if its a many-to-many relation and JoinTable is missing on both sides of the relation
            // or its one-side relation without JoinTable we should give an error
            // todo(dima): fix it
            // if (!relation.joinTable && relation.isManyToMany && (!relation.hasInverseSide || !relation.inverseRelation.joinTable))
            //     throw new MissingJoinTableError(entityMetadata, relation);
            // todo: validate if its one-to-one and side which does not have join column MUST have inverse side
            // todo: validate if its many-to-many and side which does not have join table MUST have inverse side
            // todo: if there is a relation, and inverse side is specified only on one side, shall we give error
            // todo: with message like: "Inverse side is specified only on one side of the relationship. Specify on other side too to prevent confusion".
            // todo: add validation if there two entities with the same target, and show error message with description of the problem (maybe file was renamed/moved but left in output directory)
            // todo: check if there are multiple columns on the same column applied.
            // todo: check column type if is missing in relational databases (throw new TypeORMError(`Column type of ${type} cannot be determined.`);)
            // todo: include driver-specific checks. for example in mongodb empty prefixes are not allowed
            // todo: if multiple columns with same name - throw exception, including cases when columns are in embeds with same prefixes or without prefix at all
            // todo: if multiple primary key used, at least one of them must be unique or @Index decorator must be set on entity
            // todo: check if entity with duplicate names, some decorators exist
        })

        // make sure cascade remove is not set for both sides of relationships (can be set in OneToOne decorators)
        entityMetadata.relations.forEach((relation) => {
            const isCircularCascadeRemove =
                relation.isCascadeRemove &&
                relation.inverseRelation &&
                relation.inverseRelation!.isCascadeRemove
            if (isCircularCascadeRemove)
                throw new TypeORMError(
                    `Relation ${entityMetadata.name}#${
                        relation.propertyName
                    } and ${relation.inverseRelation!.entityMetadata.name}#${
                        relation.inverseRelation!.propertyName
                    } both has cascade remove set. ` +
                        `This may lead to unexpected circular removals. Please set cascade remove only from one side of relationship.`,
                )
        }) // todo: maybe better just deny removal from one to one relation without join column?

        entityMetadata.eagerRelations.forEach((relation) => {})
    }

    /**
     * Validates dependencies of the entity metadatas.
     */
    protected validateDependencies(entityMetadatas: EntityMetadata[]) {
        const graph = new DepGraph()
        entityMetadatas.forEach((entityMetadata) => {
            graph.addNode(entityMetadata.name)
        })
        entityMetadatas.forEach((entityMetadata) => {
            entityMetadata.relationsWithJoinColumns
                .filter((relation) => !relation.isNullable)
                .forEach((relation) => {
                    graph.addDependency(
                        entityMetadata.name,
                        relation.inverseEntityMetadata.name,
                    )
                })
        })
        try {
            graph.overallOrder()
        } catch (err) {
            throw new CircularRelationsError(
                err.toString().replace("Error: Dependency Cycle Found: ", ""),
            )
        }
    }

    /**
     * Validates eager relations to prevent circular dependency in them.
     */
    protected validateEagerRelations(entityMetadatas: EntityMetadata[]) {
        entityMetadatas.forEach((entityMetadata) => {
            entityMetadata.eagerRelations.forEach((relation) => {
                if (
                    relation.inverseRelation &&
                    relation.inverseRelation.isEager
                )
                    throw new TypeORMError(
                        `Circular eager relations are disallowed. ` +
                            `${entityMetadata.targetName}#${relation.propertyPath} contains "eager: true", and its inverse side ` +
                            `${relation.inverseEntityMetadata.targetName}#${relation.inverseRelation.propertyPath} contains "eager: true" as well.` +
                            ` Remove "eager: true" from one side of the relation.`,
                    )
            })
        })
    }
}