import {
    LuaBuiltinFunction,
    LuaMultiRes,
    LuaTable,
    luaToString,
} from "$common/space_lua/runtime.ts";

export const stringApi = new LuaTable({
    byte: new LuaBuiltinFunction((s: string, i?: number, j?: number) => {
        i = i ?? 1;
        j = j ?? i;
        const result = [];
        for (let k = i; k <= j; k++) {
            result.push(s.charCodeAt(k - 1));
        }
        return new LuaMultiRes(result);
    }),
    char: new LuaBuiltinFunction((...args: number[]) => {
        return String.fromCharCode(...args);
    }),
    find: new LuaBuiltinFunction(
        (s: string, pattern: string, init?: number, plain?: boolean) => {
            init = init ?? 1;
            plain = plain ?? false;
            const result = s.slice(init - 1).match(pattern);
            if (!result) {
                return new LuaMultiRes([]);
            }
            return new LuaMultiRes([
                result.index! + 1,
                result.index! + result[0].length,
            ]);
        },
    ),
    format: new LuaBuiltinFunction((format: string, ...args: any[]) => {
        return format.replace(/%./g, (match) => {
            switch (match) {
                case "%s":
                    return luaToString(args.shift());
                case "%d":
                    return String(args.shift());
                default:
                    return match;
            }
        });
    }),
    gmatch: new LuaBuiltinFunction((s: string, pattern: string) => {
        const regex = new RegExp(pattern, "g");
        return () => {
            const result = regex.exec(s);
            if (!result) {
                return;
            }
            return new LuaMultiRes(result.slice(1));
        };
    }),
    gsub: new LuaBuiltinFunction(
        (s: string, pattern: string, repl: string, n?: number) => {
            n = n ?? Infinity;
            const regex = new RegExp(pattern, "g");
            let result = s;
            let match: RegExpExecArray | null;
            for (let i = 0; i < n; i++) {
                match = regex.exec(result);
                if (!match) {
                    break;
                }
                result = result.replace(match[0], repl);
            }
            return result;
        },
    ),
    len: new LuaBuiltinFunction((s: string) => {
        return s.length;
    }),
    lower: new LuaBuiltinFunction((s: string) => {
        return luaToString(s.toLowerCase());
    }),
    upper: new LuaBuiltinFunction((s: string) => {
        return luaToString(s.toUpperCase());
    }),
    match: new LuaBuiltinFunction(
        (s: string, pattern: string, init?: number) => {
            init = init ?? 1;
            const result = s.slice(init - 1).match(pattern);
            if (!result) {
                return new LuaMultiRes([]);
            }
            return new LuaMultiRes(result.slice(1));
        },
    ),
    rep: new LuaBuiltinFunction((s: string, n: number, sep?: string) => {
        sep = sep ?? "";
        return s.repeat(n) + sep;
    }),
    reverse: new LuaBuiltinFunction((s: string) => {
        return s.split("").reverse().join("");
    }),
    sub: new LuaBuiltinFunction((s: string, i: number, j?: number) => {
        j = j ?? s.length;
        return s.slice(i - 1, j);
    }),
    split: new LuaBuiltinFunction((s: string, sep: string) => {
        return s.split(sep);
    }),
});