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import { AggregationComputer, AggregationGroupComputer, IValue, nil, QueryError, _ISelection, _IType, _Transaction } from '../../interfaces-private.ts';import { Expr } from 'https://deno.land/x/pgsql_ast_parser@12.0.1/mod.ts';import { buildValue } from '../../parser/expression-builder.ts';import { nullIsh } from '../../utils.ts';import { DataType } from '../../interfaces.ts';import { withSelection } from '../../parser/context.ts';

class MinMax implements AggregationComputer<number> {
    constructor(private exp: IValue, private isMax: boolean) {    }
    get type(): _IType<any> {        return this.exp.type;    }
    createGroup(t: _Transaction): AggregationGroupComputer<number> {        let val: number | nil = null;        return {            feedItem: (item) => {                const value = this.exp.get(item, t);                if (!nullIsh(value) && (nullIsh(val) || (                    this.isMax                        ? val! < value                        : val! > value                ))) {                    val = value;                }            },            finish: () => val,        };    }}

export function buildMinMax(this: void, base: _ISelection, args: Expr[], op: 'max' | 'min') {    return withSelection(base, () => {        if (args.length !== 1) {            throw new QueryError(op.toUpperCase() + ' expects one argument, given ' + args.length);        }
        const what = buildValue(args[0]);
        switch (what.type.primary) {            case DataType.bigint:            case DataType.integer:            case DataType.decimal:            case DataType.date:            case DataType.float:            case DataType.text:            case DataType.time:            case DataType.timetz:            case DataType.timestamp:            case DataType.timestamptz:                break;            default:                throw new QueryError(`function min(${what.type.primary}) does not exist`, '42883');        }        return new MinMax(what, op === 'max');    });}