import {Pipe} from '../../util'

export abstract class SchemaBuilderBase {
    protected shouldDrop: 'yes'|'no'|'exists' = 'no'

    protected shouldRenameTo?: string

    constructor(
        protected readonly name: string,
    ) { }

    public drop(): this {
        this.shouldDrop = 'yes'
        return this
    }

    public dropIfExists(): this {
        this.shouldDrop = 'exists'
        return this
    }

    public rename(to: string): this {
        this.shouldRenameTo = to
        return this
    }

    pipe(): Pipe<this> {
        return Pipe.wrap<this>(this)
    }
}

export class ColumnBuilder extends SchemaBuilderBase {

}

export class IndexBuilder extends SchemaBuilderBase {

    protected fields: Set<string> = new Set<string>()

    protected removedFields: Set<string> = new Set<string>()

    protected shouldBeUnique = false

    protected shouldBePrimary = false

    protected field(name: string): this {
        this.fields.add(name)
        return this
    }

    protected removeField(name: string): this {
        this.removedFields.add(name)
        this.fields.delete(name)
        return this
    }

    primary(): this {
        this.shouldBePrimary = true
        return this
    }

    unique(): this {
        this.shouldBeUnique = true
        return this
    }
}

export class TableBuilder extends SchemaBuilderBase {

    protected columns: {[key: string]: ColumnBuilder} = {}

    protected indexes: {[key: string]: IndexBuilder} = {}

    public dropColumn(name: string): this {
        this.column(name).drop()
        return this
    }

    public renameColumn(from: string, to: string): this {
        this.column(from).rename(to)
        return this
    }

    public dropIndex(name: string): this {
        this.index(name).drop()
        return this
    }

    public renameIndex(from: string, to: string): this {
        this.index(from).rename(to)
        return this
    }

    public column(name: string) {
        if ( !this.columns[name] ) {
            this.columns[name] = new ColumnBuilder(name)
        }

        return this.columns[name]
    }

    public index(name: string) {
        if ( !this.indexes[name] ) {
            this.indexes[name] = new IndexBuilder(name)
        }

        return this.indexes[name]
    }
}