#include "gmutil.h"

#include <the_Foundation/regexp.h>
#include <the_Foundation/object.h>

void init_Url(iUrl *d, const iString *text) {
    iRegExp *absPat =
        new_RegExp("([a-z]+:)?(//[^/:?]*)(:[0-9]+)?([^?]*)(\\?.*)?", caseInsensitive_RegExpOption);
    iRegExpMatch m;
    if (matchString_RegExp(absPat, text, &m)) {
        d->protocol = capturedRange_RegExpMatch(&m, 1);
        d->host = capturedRange_RegExpMatch(&m, 2);
        if (!isEmpty_Range(&d->host)) {
            d->host.start += 2; /* skip the double slash */
        }
        d->port = capturedRange_RegExpMatch(&m, 3);
        if (!isEmpty_Range(&d->port)) {
            d->port.start++; /* omit the colon */
        }
        d->path = capturedRange_RegExpMatch(&m, 4);
        d->query = capturedRange_RegExpMatch(&m, 5);
    }
    else {
        /* Must be a relative path. */
        iZap(*d);
        iRegExp *relPat = new_RegExp("([a-z]+:)?([^?]*)(\\?.*)?", 0);
        if (matchString_RegExp(relPat, text, &m)) {
            d->protocol = capturedRange_RegExpMatch(&m, 1);
            d->path     = capturedRange_RegExpMatch(&m, 2);
            d->query    = capturedRange_RegExpMatch(&m, 3);
        }
        iRelease(relPat);
    }
    iRelease(absPat);
    if (!isEmpty_Range(&d->protocol)) {
        d->protocol.end--; /* omit the colon */
    }
}

static iRangecc dirPath_(iRangecc path) {
    const size_t pos = lastIndexOfCStr_Rangecc(&path, "/");
    if (pos == iInvalidPos) return path;
    return (iRangecc){ path.start, path.start + pos };
}

iLocalDef iBool isDef_(iRangecc cc) {
    return !isEmpty_Range(&cc);
}

static iRangecc prevPathSeg_(const char *end, const char *start) {
    iRangecc seg = { end, end };
    do {
        seg.start--;
    } while (*seg.start != '/' && seg.start != start);
    return seg;
}

void cleanUrlPath_String(iString *d) {
    iString clean;
    init_String(&clean);
    iUrl parts;
    init_Url(&parts, d);
    iRangecc seg = iNullRange;
    while (nextSplit_Rangecc(&parts.path, "/", &seg)) {
        if (equal_Rangecc(&seg, "..")) {
            /* Back up one segment. */
            iRangecc last = prevPathSeg_(constEnd_String(&clean), constBegin_String(&clean));
            truncate_Block(&clean.chars, last.start - constBegin_String(&clean));
        }
        else if (equal_Rangecc(&seg, ".")) {
            /* Skip it. */
        }
        else {
            appendCStr_String(&clean, "/");
            appendRange_String(&clean, seg);
        }
    }
    if (endsWith_Rangecc(&parts.path, "/")) {
        appendCStr_String(&clean, "/");
    }
    /* Replace with the new path. */
    if (cmpCStrNSc_Rangecc(&parts.path, cstr_String(&clean), size_String(&clean), &iCaseSensitive)) {
        const size_t pos = parts.path.start - constBegin_String(d);
        remove_Block(&d->chars, pos, size_Range(&parts.path));
        insertData_Block(&d->chars, pos, cstr_String(&clean), size_String(&clean));
    }
    deinit_String(&clean);
}

iRangecc urlHost_String(const iString *d) {
    iUrl url;
    init_Url(&url, d);
    return url.host;
}

const iString *absoluteUrl_String(const iString *d, const iString *urlMaybeRelative) {
    iUrl orig;
    iUrl rel;
    init_Url(&orig, d);
    init_Url(&rel, urlMaybeRelative);
    if (equalCase_Rangecc(&rel.protocol, "data")) {
        /* Special case, the contents should be left unparsed. */
        return urlMaybeRelative;
    }
    const iBool isRelative = !isDef_(rel.host);
    iRangecc protocol = range_CStr("gemini");
    if (isDef_(rel.protocol)) {
        protocol = rel.protocol;
    }
    else if (isRelative && isDef_(orig.protocol)) {
        protocol = orig.protocol;
    }
    iString *absolute = collectNew_String();
    appendRange_String(absolute, protocol);
    appendCStr_String(absolute, "://"); {
        const iUrl *selHost = isDef_(rel.host) ? &rel : &orig;
        appendRange_String(absolute, selHost->host);
        if (!isEmpty_Range(&selHost->port)) {
            appendCStr_String(absolute, ":");
            appendRange_String(absolute, selHost->port);
        }
    }
    if (isDef_(rel.protocol) || isDef_(rel.host) || startsWith_Rangecc(&rel.path, "/")) {
        appendRange_String(absolute, rel.path); /* absolute path */
    }
    else {
        if (!endsWith_Rangecc(&orig.path, "/")) {
            /* Referencing a file. */
            appendRange_String(absolute, dirPath_(orig.path));
        }
        else {
            /* Referencing a directory. */
            appendRange_String(absolute, orig.path);
        }
        if (!endsWith_String(absolute, "/")) {
            appendCStr_String(absolute, "/");
        }
        appendRange_String(absolute, rel.path);
    }
    appendRange_String(absolute, rel.query);
    cleanUrlPath_String(absolute);
    return absolute;
}

void urlEncodeSpaces_String(iString *d) {
    for (;;) {
        const size_t pos = indexOfCStr_String(d, " ");
        if (pos == iInvalidPos) break;
        remove_Block(&d->chars, pos, 1);
        insertData_Block(&d->chars, pos, "%20", 3);
    }
}

static const struct {
    enum iGmStatusCode code;
    iGmError           err;
} errors_[] = {
    { unknownStatusCode_GmStatusCode, /* keep this as the first one (fallback return value) */
      { 0x1f4ab, /* dizzy */
        "Unknown Status Code",
        "The server responded with a status code that is not specified in the Gemini "
        "protocol as known to this client. Maybe the server is from the future? Or "
        "just malfunctioning."} },
    { failedToOpenFile_GmStatusCode,
      { 0x1f4c1, /* file folder */
        "Failed to Open File",
        "The requested file does not exist or is inaccessible. "
        "Please check the file path." } },
    { unsupportedMimeType_GmStatusCode,
      { 0x1f47d, /* alien */
        "Unsupported MIME Type",
        "The received content is in an unsupported format and cannot be viewed with "
        "this application." } },
    { invalidHeader_GmStatusCode,
      { 0x1f4a9, /* pile of poo */
        "Invalid Header",
        "The received header did not conform to the Gemini specification. "
        "Perhaps the server is malfunctioning or you tried to contact a "
        "non-Gemini server." } },
    { invalidRedirect_GmStatusCode,
      { 0, /*  */
        "Invalid Redirect",
        "The server responded with a redirect but did not provide a valid destination URL. "
        "Perhaps the server is malfunctioning." } },
    { temporaryFailure_GmStatusCode,
      { 0x1f50c, /* electric plug */
        "Temporary Failure",
        "The request has failed, but may succeed if you try again in the future." } },
    { serverUnavailable_GmStatusCode,
      { 0x1f525, /* fire */
        "Server Unavailable",
        "The server is unavailable due to overload or maintenance. Check back later." } },
    { cgiError_GmStatusCode,
      { 0x1f4a5, /* collision */
        "CGI Error",
        "Failure during dynamic content generation on the server. This may be due "
        "to buggy serverside software." } },
    { proxyError_GmStatusCode,
      { 0x1f310, /* globe */
        "Proxy Error",
        "A proxy request failed because the server was unable to successfully "
        "complete a transaction with the remote host. Perhaps there are difficulties "
        "with network connectivity." } },
    { slowDown_GmStatusCode,
      { 0x1f40c, /* snail */
        "Slow Down",
        "The server is rate limiting requests. Please wait..." } },
    { permanentFailure_GmStatusCode,
      { 0x1f6ab, /* no entry */
        "Permanent Failure",
        "Your request has failed and will fail in the future as well if repeated." } },
    { notFound_GmStatusCode,
      { 0x1f50d, /* magnifying glass */
        "Not Found",
        "The requested resource could not be found at this time." } },
    { gone_GmStatusCode,
      { 0x1f47b, /* ghost */
        "Gone",
        "The resource requested is no longer available and will not be available again." } },
    { proxyRequestRefused_GmStatusCode,
      { 0x1f6c2, /* passport control */
        "Proxy Request Refused",
        "The request was for a resource at a domain not served by the server and the "
        "server does not accept proxy requests." } },
    { badRequest_GmStatusCode,
      { 0x1f44e, /* thumbs down */
        "Bad Request",
        "The server was unable to parse your request, presumably due to the "
        "request being malformed. Likely a bug in Lagrange." } },
    { clientCertificateRequired_GmStatusCode,
      { 0x1f511, /* key */
        "Certificate Required",
        "Access to the requested resource requires identification via "
        "a client certificate." } },
    { certificateNotAuthorized_GmStatusCode,
      { 0x1f512, /* lock */
        "Certificate Not Authorized",
        "The provided client certificate is valid but is not authorized for accessing "
        "the requested resource. " } },
    { certificateNotValid_GmStatusCode,
      { 0x1f6a8, /* revolving light */
        "Invalid Certificate",
        "The provided client certificate is expired or invalid." } },
};

iBool isDefined_GmError(enum iGmStatusCode code) {
    iForIndices(i, errors_) {
        if (errors_[i].code == code) {
            return iTrue;
        }
    }
    return iFalse;
}

const iGmError *get_GmError(enum iGmStatusCode code) {
    static const iGmError none = { 0, "", "" };
    if (code == 0) {
        return &none;
    }
    iForIndices(i, errors_) {
        if (errors_[i].code == code) {
            return &errors_[i].err;
        }
    }
    iAssert(errors_[0].code == unknownStatusCode_GmStatusCode);
    return &errors_[0].err; /* unknown */
}