import {Command, ParseContext, processPath, StrTerm, wrapString} from "./command.js";
import {LexInput} from "../lexer.js";
import {StrVM} from "../vm.js";
import {Awaitable} from "../../util/types.js";
import fs from "node:fs/promises";

export class InFile extends Command<{ path: StrTerm }> {
    isParseCandidate(token: LexInput): boolean {
        return this.isKeyword(token, 'infile')
    }

    async attemptParse(context: ParseContext): Promise<{ path: StrTerm }> {
        return { path: await context.popTerm() }
    }

    getDisplayName(): string {
        return 'infile'
    }

    execute(vm: StrVM, data: { path: StrTerm }): Awaitable<StrVM> {
        return vm.replaceContextMatchingTerm(ctx => ({
            override: async () => {
                const path = processPath(ctx.resolveString(data.path))
                const content = await fs.readFile(path, 'utf8')
                return wrapString(content)
            }
        }))
    }
}