import z from "zod";
import { CommandExec } from "./cmdtypes.ts";

export interface CommandOptions {
    key: string[],
    subcommands?: Command[],
    exec?: CommandExec,
    zod?: z.ZodTuple,
    help?: string
}

export default class Command {

    subCmds: Command[];
    key: string[];
    exec: CommandExec | null;
    validate: z.ZodTuple | null;
    help: string | null;
    #argsLength: number;

    constructor(options: CommandOptions) {
        this.subCmds = options.subcommands || [];
        this.key = options.key;
        this.exec = options.exec || null;
        this.validate = options.zod || null;
        this.help = options.help || null;
        this.#argsLength = options.zod ? options.zod.def.items.length : 0;
    }

    getKey() {
        return this.key;
    }

    dispatch(...args: unknown[]): unknown | Promise<unknown> {
        const root = args[0] as string | undefined;
        if (!root && this.exec)
            return this.exec(...args);
        else if (!root) return new Error('No execution target for this root');

        const cmd = this.subCmds.find(cmd => cmd.getKey().includes(root));
        if (cmd) {
            const newArgs = args.slice(1);
            if (cmd.#argsLength && newArgs.length !== cmd.#argsLength && cmd.help) return new Error(cmd.help);
            if (cmd.validate) {
                const res = cmd.validate.safeParse(newArgs);
                if (res.success) return cmd.dispatch(...res.data);
                else if (cmd.help) return new Error(cmd.help);
                else if (cmd.#argsLength) return new Error(`'${root}' validation error: expected ${cmd.#argsLength} args, got ${newArgs.length}`);
                else return new Error(`'${root}' validation error`);
            }
        }

        if (this.exec)
            return this.exec(...args);
        else return new Error(`'${root}': Subcommand not found (args: "${args.join(" ")}")`);
    }

}