#include "PsychicStaticFileHandler.h"

/*************************************/
/*  PsychicStaticFileHandler         */
/*************************************/

PsychicStaticFileHandler::PsychicStaticFileHandler(const char * uri, FS & fs, const char * path, const char * cache_control)
    : _fs(fs)
    , _uri(uri)
    , _path(path)
    , _default_file("index.html")
    , _cache_control(cache_control)
    , _last_modified("") {
    // Ensure leading '/'
    if (_uri.length() == 0 || _uri[0] != '/')
        _uri = "/" + _uri;
    if (_path.length() == 0 || _path[0] != '/')
        _path = "/" + _path;

    // If path ends with '/' we assume a hint that this is a directory to improve performance.
    // However - if it does not end with '/' we, can't assume a file, path can still be a directory.
    _isDir = _path[_path.length() - 1] == '/';

    // Remove the trailing '/' so we can handle default file
    // Notice that root will be "" not "/"
    if (_uri[_uri.length() - 1] == '/')
        _uri = _uri.substring(0, _uri.length() - 1);
    if (_path[_path.length() - 1] == '/')
        _path = _path.substring(0, _path.length() - 1);

    // Reset stats
    _gzipFirst = false;
    _gzipStats = 0xF8;
}

PsychicStaticFileHandler & PsychicStaticFileHandler::setIsDir(bool isDir) {
    _isDir = isDir;
    return *this;
}

PsychicStaticFileHandler & PsychicStaticFileHandler::setDefaultFile(const char * filename) {
    _default_file = String(filename);
    return *this;
}

PsychicStaticFileHandler & PsychicStaticFileHandler::setCacheControl(const char * cache_control) {
    _cache_control = String(cache_control);
    return *this;
}

PsychicStaticFileHandler & PsychicStaticFileHandler::setLastModified(const char * last_modified) {
    _last_modified = String(last_modified);
    return *this;
}

PsychicStaticFileHandler & PsychicStaticFileHandler::setLastModified(struct tm * last_modified) {
    char result[30];
    strftime(result, 30, "%a, %d %b %Y %H:%M:%S %Z", last_modified);
    return setLastModified((const char *)result);
}

bool PsychicStaticFileHandler::canHandle(PsychicRequest * request) {
    if (request->method() != HTTP_GET || !request->uri().startsWith(_uri))
        return false;

    if (_getFile(request))
        return true;

    return false;
}

bool PsychicStaticFileHandler::_getFile(PsychicRequest * request) {
    // Remove the found uri
    String path = request->uri().substring(_uri.length());

    // We can skip the file check and look for default if request is to the root of a directory or that request path ends with '/'
    bool canSkipFileCheck = (_isDir && path.length() == 0) || (path.length() && path[path.length() - 1] == '/');

    path = _path + path;

    // Do we have a file or .gz file
    if (!canSkipFileCheck && _fileExists(path))
        return true;

    // Can't handle if not default file
    if (_default_file.length() == 0)
        return false;

    // Try to add default file, ensure there is a trailing '/' ot the path.
    if (path.length() == 0 || path[path.length() - 1] != '/')
        path += "/";
    path += _default_file;

    return _fileExists(path);
}

#define FILE_IS_REAL(f) (f == true && !f.isDirectory())

bool PsychicStaticFileHandler::_fileExists(const String & path) {
    bool fileFound = false;
    bool gzipFound = false;

    String gzip = path + ".gz";

    if (_gzipFirst) {
        _file     = _fs.open(gzip, "r");
        gzipFound = FILE_IS_REAL(_file);
        if (!gzipFound) {
            _file     = _fs.open(path, "r");
            fileFound = FILE_IS_REAL(_file);
        }
    } else {
        _file     = _fs.open(path, "r");
        fileFound = FILE_IS_REAL(_file);
        if (!fileFound) {
            _file     = _fs.open(gzip, "r");
            gzipFound = FILE_IS_REAL(_file);
        }
    }

    bool found = fileFound || gzipFound;

    if (found) {
        _filename = path;

        // Calculate gzip statistic
        _gzipStats = (_gzipStats << 1) + (gzipFound ? 1 : 0);
        if (_gzipStats == 0x00)
            _gzipFirst = false; // All files are not gzip
        else if (_gzipStats == 0xFF)
            _gzipFirst = true; // All files are gzip
        else
            _gzipFirst = _countBits(_gzipStats) > 4; // IF we have more gzip files - try gzip first
    }

    return found;
}

uint8_t PsychicStaticFileHandler::_countBits(const uint8_t value) const {
    uint8_t w = value;
    uint8_t n;
    for (n = 0; w != 0; n++)
        w &= w - 1;
    return n;
}

esp_err_t PsychicStaticFileHandler::handleRequest(PsychicRequest * request) {
    if (_file == true) {
        DUMP(_filename);

        //is it not modified?
        String etag = String(_file.size());
        if (_last_modified.length() && _last_modified == request->header("If-Modified-Since")) {
            DUMP("Last Modified Hit");
            TRACE();
            _file.close();
            request->reply(304); // Not modified
        }
        //does our Etag match?
        else if (_cache_control.length() && request->hasHeader("If-None-Match") && request->header("If-None-Match").equals(etag)) {
            DUMP("Etag Hit");
            DUMP(etag);
            DUMP(_cache_control);

            _file.close();

            PsychicResponse response(request);
            response.addHeader("Cache-Control", _cache_control.c_str());
            response.addHeader("ETag", etag.c_str());
            response.setCode(304);
            response.send();
        }
        //nope, send them the full file.
        else {
            DUMP("No cache hit");
            DUMP(_last_modified);
            DUMP(_cache_control);

            PsychicFileResponse response(request, _fs, _filename);

            if (_last_modified.length())
                response.addHeader("Last-Modified", _last_modified.c_str());
            if (_cache_control.length()) {
                response.addHeader("Cache-Control", _cache_control.c_str());
                response.addHeader("ETag", etag.c_str());
            }

            return response.send();
        }
    } else {
        return request->reply(404);
    }

    return ESP_OK;
}