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import { _IIndex, IValue, _ITable, _IDb, _Transaction, _Explainer, _IndexExplanation, IndexOp, IndexKey, Stats } from '../interfaces-private.ts';import { PermissionDeniedError, NotSupported } from '../interfaces.ts';
interface IndexSubject<T> {    readonly size: number;    readonly column: IValue;    byColumnValue(columnValue: string, t: _Transaction): T[];}
export class CustomIndex<T> implements _IIndex<T> {    readonly expressions: IValue<any>[];

    explain(e: _Explainer): _IndexExplanation {        throw new Error('not implemented');    }
    constructor(readonly onTable: _ITable<T>, private subject: IndexSubject<T>) {        this.expressions = [this.subject.column];    }
    get indexName(): string {        return null as any;    }
    entropy(): number {        return this.subject.size;    }
    stats(t: _Transaction, key?: IndexKey): Stats | null {        return null;    }
    iterateKeys() {        return null;    }
    add(raw: any): void {        throw new PermissionDeniedError();    }
    eqFirst([key]: any, t: _Transaction) {        for (const its of this.subject.byColumnValue(key, t)) {            return its;        }        return null;    }

    enumerate(op: IndexOp): Iterable<T> {        switch (op.type) {            case 'eq':                return this.eq(op.key, op.t);            case 'neq':                return this.neq(op.key, op.t);            case 'ge':                return this.ge(op.key, op.t);            case 'le':                return this.le(op.key, op.t);            case 'gt':                return this.gt(op.key, op.t);            case 'lt':                return this.lt(op.key, op.t);            case 'outside':                return this.outside(op.lo, op.hi, op.t);            case 'inside':                return this.inside(op.lo, op.hi, op.t);            case 'nin':                return this.nin(op.keys, op.t);            default:                throw NotSupported.never(op['type']);        }    }
    * eq([rawKey]: any, t: _Transaction): Iterable<any> {        for (const its of this.subject.byColumnValue(rawKey, t)) {            yield its;        }    }
    * nin(keys: any[][], t: _Transaction) {        const raws = keys.map(x => x[0]) as any[];        for (const i of this.onTable.selection.enumerate(t)) {            const val = this.subject.column.get(i, t);            if (raws.includes(val)) {                continue;            }            yield i;        }    }
    * neq([rawKey]: any, t: _Transaction) {        for (const i of this.onTable.selection.enumerate(t)) {            const val = this.subject.column.get(i, t);            if (val !== rawKey) {                yield i;            }        }    }    * gt(rawKey: any, t: _Transaction): Iterable<any> {        for (const i of this.onTable.selection.enumerate(t)) {            const val = this.subject.column.get(i, t);            if (val > rawKey) {                yield i;            }        }    }    * lt(rawKey: any, t: _Transaction): Iterable<any> {        for (const i of this.onTable.selection.enumerate(t)) {            const val = this.subject.column.get(i, t);            if (val < rawKey) {                yield i;            }        }    }    * ge(rawKey: any, t: _Transaction): Iterable<any> {        for (const i of this.onTable.selection.enumerate(t)) {            const val = this.subject.column.get(i, t);            if (val >= rawKey) {                yield i;            }        }    }    * le(rawKey: any, t: _Transaction): Iterable<any> {        for (const i of this.onTable.selection.enumerate(t)) {            const val = this.subject.column.get(i, t);            if (val <= rawKey) {                yield i;            }        }    }
    *outside(lo: IndexKey, hi: IndexKey, t: _Transaction): Iterable<T> {        yield* this.lt(lo, t);        yield* this.gt(hi, t);    }
    *inside(lo: IndexKey, hi: IndexKey, t: _Transaction): Iterable<T> {        throw new Error('Not implemented');    }}