module uselesshttpd.util;

/*
    lost+skunk <git.macaw.me/skunky>, 2025;
    Licensed under WTFPL
*/

char[] intToStr(T)(T num) {
    char[] buf;
    for(short i; num > 0; ++i) {
        buf = (num % 10 + '0')~buf;
        num /= 10;
    }
    return buf;
}

void err(int e, string msg) {
    if (e != 0)
        throw new Exception("Something went wrong: failed to "~msg~'.');
}

// UDA
struct Location { string path; }
// enum method;

string getStatus(short status) {
    static foreach(mmbr; __traits(allMembers, Statuses))
        if (__traits(getMember, Statuses, mmbr) == status)
            return __traits(getAttributes, __traits(getMember, Statuses, mmbr))[0];
    return "WTF";
}

// FIXME: memory leak
void append(char[]* src, char symb) @nogc {
    import core.memory: pureMalloc, pureFree;
    auto arr = 
        cast (char[])
        pureMalloc(src.length + 1)
        [0..src.length + 1];

    arr[$-1..$] = symb;
    arr[0..$-1] = *src;
    *src = arr;

    arr = null;
    pureFree(arr.ptr);
}

void parseAndValidateURL(char[] url, Request* rqst) {
    if (url.length > 2048) throw new Exception("Too long URL");
    rqst.path = null;
    bool notArgumentPart;
    scope (exit) append(&rqst.args, '&');
    for (short i; i < url.length; ++i) {
        switch (url[i]) {
            case '?':
                if (notArgumentPart) goto default;
                notArgumentPart = true;
                break;
            case '/':
                if (url.length > i+1 && url[i+1] != '/') append(&rqst.path, '/');
                break;
            case '=', '&':
                if (notArgumentPart && url[i-1] != url[i]) append(&rqst.args, url[i]);
                break;

            case 'A': .. case 'Z':
            case 'a': .. case 'z':
            case '0': .. case '9':
            case '-', '_', '.', '~', '!', '$', '\'', '(', ')', '*', '+', ',', ';', '@', '[', ']', '|', '%':
                if (notArgumentPart) append(&rqst.args, url[i]);
                else append(&rqst.path, url[i]);
                break;
            default: throw new Exception("Malformed URL");
        }
    }
}

struct Request {
    enum Methods {
        GET = "GET",
        PUT = "PUT",
        POST = "POST",
        DELETE = "DELETE",
        OPTIONS = "OPTIONS",
        // остальное лень реализовывать, да и не трэба..
    }

    Methods method;
    void[] body;
    string[string] headers;
    
    char[] path;
    char[] args;
    char[] getArgument(string arg) @nogc nothrow {
        short split, prev;
        for (short i; i < args.length; ++i) {
            if (args[i] == '=') split = i;
            else if (args[i] == '&') {
                if (arg == args[prev..split]) return args[split+1..i];
                prev = ++i;
            }
        }
        return null;
    }
}

private static enum Statuses: short { // спизженно с https://github.com/zigzap/zap/blob/675c65b509d48c21a8d1fa4c5ec53fc407643a3b/src/http.zig#L6
    // Information responses
    @("Continue") continuee = 100,
    @("Switching Protocols") switching_protocols = 101,
    @("Processing") processing = 102, // (WebDAV)
    @("Early Hints") early_hints = 103,

    // Successful responses
    @("OK") ok = 200,
    @("Created") created = 201,
    @("Accepted") accepted = 202,
    @("Non-Authoritative Information") non_authoritative_information = 203,
    @("No Content") no_content = 204,
    @("Reset Content") reset_content = 205,
    @("Partial Content") partial_content = 206,
    @("Multi-Status") multi_status = 207, // (WebDAV)
    @("Already Reported") already_reported = 208, // (WebDAV)
    @("IM Used") im_used = 226, // (HTTP Delta encoding)

    // Redirection messages
    @("Multiple Choices") multiple_choices = 300,
    @("Moved Permanently") moved_permanently = 301,
    @("Found") found = 302,
    @("See Other") see_other = 303,
    @("Not Modified") not_modified = 304,
    @("Use Proxy") use_proxy = 305,
    @("Unused") unused = 306,
    @("Temporary Redirect") temporary_redirect = 307,
    @("Permanent Redirect") permanent_redirect = 308,

    // Client error responses
    @("Bad Request") bad_request = 400,
    @("Unauthorized") unauthorized = 401,
    @("Payment Required") payment_required = 402,
    @("Forbidden") forbidden = 403,
    @("Not Found") not_found = 404,
    @("Method Not Allowed") method_not_allowed = 405,
    @("Not Acceptable") not_acceptable = 406,
    @("Proxy Authentication Required") proxy_authentication_required = 407,
    @("Request Timeout") request_timeout = 408,
    @("Conflict") conflict = 409,
    @("Gone") gone = 410,
    @("Length Required") length_required = 411,
    @("Precondition Failed") precondition_failed = 412,
    @("Payload Too Large") payload_too_large = 413,
    @("URI Too Long") uri_too_long = 414,
    @("Unsupported Media Type") unsupported_media_type = 415,
    @("Range Not Satisfiable") range_not_satisfiable = 416,
    @("Expectation Failed") expectation_failed = 417,
    @("I'm a teapot") im_a_teapot = 418,
    @("Misdirected Request") misdirected_request = 421,
    @("Unprocessable Content") unprocessable_content = 422, // (WebDAV)
    @("Locked") locked = 423, // (WebDAV)
    @("Failed Dependency") failed_dependency = 424, // (WebDAV)
    @("Too Early") too_early = 425,
    @("Upgrade Required") upgrade_required = 426,
    @("Precondition Required") precondition_required = 428,
    @("Too Many Requests") too_many_requests = 429,
    @("Request Header Fields Too Large") request_header_fields_too_large = 431,
    @("Unavailable For Legal Reasons") unavailable_for_legal_reasons = 451,

    // Server error responses
    @("Internal Server Error") internal_server_error = 500,
    @("Not Implemented") not_implemented = 501,
    @("Bad Gateway") bad_gateway = 502,
    @("Service Unavailable") service_unavailable = 503,
    @("Gateway Timeout") gateway_timeout = 504,
    @("HTTP Version Not Supported") http_version_not_supported = 505,
    @("Variant Also Negotiates") variant_also_negotiates = 506
}