import {Model} from './Model'
import {AbstractBuilder} from '../builder/AbstractBuilder'
import {AbstractResultIterable} from '../builder/result/AbstractResultIterable'
import {Instantiable, StaticClass} from '../../di'
import {ModelResultIterable} from './ModelResultIterable'
import {Collection} from '../../util'
import {ConstraintOperator, ModelKey, ModelKeys} from '../types'
import {EscapeValue} from '../dialect/SQLDialect'
import {Scope, ScopeClosure} from './scope/Scope'

/**
 * Implementation of the abstract builder whose results yield instances of a given Model, `T`.
 */
export class ModelBuilder<T extends Model<T>> extends AbstractBuilder<T> {
    protected eagerLoadRelations: (keyof T)[] = []

    protected appliedScopes: Collection<{ accessor: string | Instantiable<Scope>, scope: ScopeClosure }> = new Collection<{accessor: string | Instantiable<Scope>; scope: ScopeClosure}>()

    constructor(
        /** The model class that is created for results of this query. */
        protected readonly ModelClass: StaticClass<T, typeof Model> & Instantiable<T>,
    ) {
        super()
    }

    public withScopes(scopes: Collection<{ accessor: string | Instantiable<Scope>, scope: ScopeClosure }>): this {
        this.appliedScopes = scopes.clone()
        return this
    }

    public getNewInstance(): AbstractBuilder<T> {
        return this.app().make<ModelBuilder<T>>(ModelBuilder, this.ModelClass)
    }

    public getResultIterable(): AbstractResultIterable<T> {
        return this.app().make<ModelResultIterable<T>>(ModelResultIterable, this.finalize(), this.registeredConnection, this.ModelClass)
    }

    /**
     * Get a copy of this builder with all of its values finalized.
     * @override to apply scopes
     */
    public finalize(): AbstractBuilder<T> {
        const inst = super.finalize()
        this.appliedScopes.each(rec => rec.scope(inst))
        return inst
    }

    /**
     * Apply a WHERE...IN... constraint on the primary key of the model.
     * @param keys
     */
    public whereKey(keys: ModelKeys): this {
        return this.whereIn(
            this.ModelClass.qualifyKey(),
            this.normalizeModelKeys(keys),
        )
    }

    /**
     * Apply a where constraint on the column corresponding the the specified
     * property on the model.
     * @param propertyName
     * @param operator
     * @param operand
     */
    public whereProperty(propertyName: string, operator: ConstraintOperator, operand?: EscapeValue): this {
        return this.where(
            this.ModelClass.propertyToColumn(propertyName),
            operator,
            operand,
        )
    }

    /**
     * Mark a relation to be eager-loaded.
     * @param relationName
     */
    public with(relationName: keyof T): this {
        if ( !this.eagerLoadRelations.includes(relationName) ) {
            // Try to load the Relation, so we fail if the name is invalid
            this.make<T>(this.ModelClass).getRelation(relationName)
            this.eagerLoadRelations.push(relationName)
        }

        return this
    }

    /**
     * Prevent a relation from being eager-loaded.
     * @param relationName
     */
    public without(relationName: keyof T): this {
        this.eagerLoadRelations = this.eagerLoadRelations.filter(name => name !== relationName)
        return this
    }

    /**
     * Remove all global scopes from this query.
     */
    public withoutGlobalScopes(): this {
        this.appliedScopes = new Collection<{accessor: string | Instantiable<Scope>; scope: ScopeClosure}>()
        return this
    }

    /**
     * Remove a specific scope from this query by its identifier.
     * @param name
     */
    public withoutGlobalScope(name: string | Instantiable<Scope>): this {
        this.appliedScopes = this.appliedScopes.where('accessor', '=', name)
        return this
    }

    /** Get the list of relations to eager-load. */
    public getEagerLoadedRelations(): (keyof T)[] {
        return [...this.eagerLoadRelations]
    }

    /**
     * Given some format of keys of the model, try to normalize them to a flat array.
     * @param keys
     * @protected
     */
    protected normalizeModelKeys(keys: ModelKeys): ModelKey[] {
        if ( Array.isArray(keys) ) {
            return keys
        } else if ( keys instanceof Collection ) {
            return keys.all()
        }

        return [keys]
    }

    /**
     * Create a copy of this builder.
     * @override to add implementation-specific pass-alongs.
     */
    public clone(): ModelBuilder<T> {
        const inst = super.clone() as ModelBuilder<T>
        inst.eagerLoadRelations = [...this.eagerLoadRelations]
        inst.appliedScopes = this.appliedScopes.clone()
        return inst
    }
}