#include <ESPAsyncWebServer.h>
#include "FilesystemAbstraction.h"


#define FLASH_TEXT(name) const char *name

namespace webdav_constants
{
    FLASH_TEXT(MULTISTATUS_START) = "<?xml version=\"1.0\" ?><D:multistatus xmlns:D=\"DAV:\">";
    FLASH_TEXT(MULTISTATUS_END) = "</D:multistatus>";
    FLASH_TEXT(RESPONSE_START) = "<D:response>";
    FLASH_TEXT(RESPONSE_END) = "</D:response>\n";
    FLASH_TEXT(HREF_START) = "<D:href>";
    FLASH_TEXT(HREF_END) = "</D:href>";
    FLASH_TEXT(PROPSTAT_START) = "<D:propstat>";
    FLASH_TEXT(PROPSTAT_END) = "</D:propstat>";
    FLASH_TEXT(PROP_START) = "<D:prop>";
    FLASH_TEXT(PROP_END) = "</D:prop>";
    FLASH_TEXT(RESOURCETYPE_START) = "<D:resourcetype>";
    FLASH_TEXT(RESOURCETYPE_END) = "</D:resourcetype>";
    FLASH_TEXT(RESOURCE_COLLECTION) = "<D:collection/>";
    FLASH_TEXT(HTTP_204_NO_CONTENT) = "HTTP/1.1 204 No Content";

    FLASH_TEXT(CONTENTLEN_START) = "<D:getcontentlength>";
    FLASH_TEXT(CONTENTLEN_END) = "</D:getcontentlength>";
    FLASH_TEXT(CREATEDATE_START) = "<D:creationdate>";
    FLASH_TEXT(CREATEDATE_END) = "</D:creationdate>";
    FLASH_TEXT(MODDATE_START) = "<D:getlastmodified>";
    FLASH_TEXT(MODDATE_END) = "</D:getlastmodified>";
    FLASH_TEXT(STATUS_OK) = "<D:status>HTTP/1.1 200 OK</D:status>";
} // namespace webdav_constants

class WebdavFileListCallback
{
public:
    WebdavFileListCallback(const String &path)
        : path_(path), headerWritten_(false), finished_(false)
    {
        dir_ = portablefs::openDir(path);
    }

    size_t operator()(uint8_t *buffer, size_t maxLen, size_t index)
    {
        Serial.print("index ");
        Serial.println(index);

        using namespace webdav_constants;
        uint8_t *bufferStart = buffer;

        if (finished_)
            return 0;

        if (!headerWritten_)
        {
            toBuffer(buffer, MULTISTATUS_START);
            headerWritten_ = true;
        }

        bool fileFound = false;
        while (dir_.next())
        {
            if (isFirstFileOfTrainingGroup())
            {
                fileFound = true;
                break;
            }
        }

        if (fileFound)
        {
            //toBuffer(buffer, path_.c_str());
            toBuffer(buffer, RESPONSE_START);
            toBuffer(buffer, HREF_START);
            const auto fileName = dir_.fileName();
            const auto fileNameWithoutDir = fileName.substring(fileName.lastIndexOf("/") + 1);
            String fileBaseName = fileNameWithoutDir.substring(0, fileNameWithoutDir.indexOf('_'));
            fileBaseName += ".st";
            toBuffer(buffer, fileBaseName.c_str());
            toBuffer(buffer, HREF_END);
            toBuffer(buffer, PROPSTAT_START);
            toBuffer(buffer, PROP_START);
            if (dir_.isDirectory())
            {
                toBuffer(buffer, RESOURCETYPE_START);
                toBuffer(buffer, RESOURCE_COLLECTION);
                toBuffer(buffer, RESOURCETYPE_END);
            }
            else
            {
                toBuffer(buffer, CONTENTLEN_START);
                String fileSizeStr(getFileSize(fileName));
                toBuffer(buffer, fileSizeStr.c_str());
                toBuffer(buffer, CONTENTLEN_END);
            }

            toBuffer(buffer, PROP_END);
            toBuffer(buffer, STATUS_OK);
            toBuffer(buffer, PROPSTAT_END);
            toBuffer(buffer, webdav_constants::RESPONSE_END);
        }
        else
        {
            toBuffer(buffer, MULTISTATUS_END);
            finished_ = true;
        }

        size_t bytesWritten = buffer - bufferStart;
        assert_msg(bytesWritten < maxLen, "Written too much!");
        //Serial.print("Bytes written ");
        //Serial.println(bytesWritten);
        //Serial.print("Max bytes ");
        //Serial.println(maxLen);
        return bytesWritten;
    }

private:
    bool isFirstFileOfTrainingGroup()
    {
        return !dir_.isDirectory() && dir_.fileName().endsWith("_0");
    }

    size_t getFileSize(const String &fileZero)
    {
        size_t size = 0;
        auto fileBase = fileZero.substring(0, fileZero.indexOf('_'));
        auto newDirInstance = portablefs::openDir(path_);
        while (newDirInstance.next())
            if (newDirInstance.isFile() && newDirInstance.fileName().startsWith(fileBase))
                size += newDirInstance.fileSize();
        return size;
    }

    void toBuffer(uint8_t *&buffer, const char *text)
    {
        auto len = strlen(text);
        memcpy(buffer, text, len);
        buffer += len;
    }

    portablefs::Dir dir_;
    const String path_;
    bool headerWritten_;
    bool finished_;
};

bool deleteMeasurementFiles(const String &stName, const String &folder)
{
    String baseName = folder + "/" + stName.substring(0, stName.indexOf("."));
    int counter = 0;
    {
        auto d = portablefs::openDir(folder);
        while (d.next())
            if (d.isFile() && d.fileName().startsWith(baseName))
                ++counter;
    }
    if (counter == 0)
        return false;

    for (int i = 0; i < counter; ++i)
    {
        const String pathToDelete = baseName + "_" + String(i);
        if (!SPIFFS.remove(pathToDelete))
            return false;
    }
    return true;
}

class SpiffsWebDavHandler : public AsyncWebHandler
{
public:
    SpiffsWebDavHandler(const String &prefix, const String &folder)
        : prefix_(prefix), folder_(folder)
    {
    }

    virtual bool canHandle(AsyncWebServerRequest *request) override final
    {
        Serial.print("Can handle for url : ");
        Serial.println(request->url());
        return request->url().startsWith(prefix_);
    }

    virtual void handleRequest(AsyncWebServerRequest *request) override final
    {
        if (request->url() == prefix_ + "/" && (request->method() == HTTP_GET || request->method() == HTTP_PROPFIND))
        {
            // send chunked response - it is too large to send in one go
            auto response = request->beginChunkedResponse("application/xml",
                                                          WebdavFileListCallback(folder_));
            request->send(response);
        } /* 
        else if(request->url() == prefix_ + "/" && request->method() == HTTP_GET) {
            AsyncResponseStream * response = request->beginResponseStream("text/plain", 1460*10);
            Dir dir = SPIFFS.openDir(folder_);
            Serial.print("Opening folder ");
            Serial.println(folder_);
            while (dir.next()) {
                Serial.print("  File: ");
                Serial.println(dir.fileName());
                response->println(dir.fileName());
            }
            request->send(response);
        }*/
        else if (request->method() == HTTP_GET)
        {
            auto path = folder_ + request->url().substring(prefix_.length());
            if (SPIFFS.exists(path))
                request->send(SPIFFS, path, "application/x-msgpack");
            else
                request->send(404, "text/plain", "Webdav: File not found");
        }
        else if (request->method() == HTTP_DELETE)
        {
            auto stFileName = request->url().substring(prefix_.length() + 1);
            Serial.print("HTTP_DELETE for ");
            Serial.println(stFileName);
            bool deleteSuccessful = deleteMeasurementFiles(stFileName, folder_);
            if (deleteSuccessful)
                request->send(204, "text/plain", "Success");
            else
                request->send(404, "text/plain", "Webdav: File to delete not found");
        }
        else
        {
            request->send(404, "text/plain", "Webdav: Invalid request");
        }
    }
    virtual bool isRequestHandlerTrivial() override final { return false; }

private:
    String prefix_;
    String folder_;
};