import {Command, hashStrRVal, ParseContext, unwrapDestructured, wrapDestructured, wrapString} from "./command.js";
import {LexInput} from "../lexer.js";
import {StrVM} from "../vm.js";
import {Awaitable} from "../../util/types.js";

export class Unique extends Command<{}> {
    isParseCandidate(token: LexInput): boolean {
        return this.isKeyword(token, 'unique')
    }

    attemptParse(context: ParseContext): {} {
        return {}
    }

    getDisplayName(): string {
        return 'unique'
    }

    execute(vm: StrVM): Awaitable<StrVM> {
        return vm.tapInPlace(ctx =>
            ctx.replaceSubject(sub => {
                const seen: Record<string, boolean> = {}
                return wrapDestructured(
                    unwrapDestructured(sub)
                        .filter(part => {
                            const hash = hashStrRVal(wrapString(part.value))
                            if ( seen[hash] ) {
                                return false
                            }

                            seen[hash] = true
                            return true
                        }))
            }))
    }
}