#include "webdav.hpp"

#include <sys/stat.h>
#include <dirent.h>
#include <regex>
#include "curl/curl.h"
#include "curl/easy.h"
#include <tinyxml2/tinyxml2.h>

using namespace std;
using namespace tinyxml2;

WebDavClient::WebDavClient(string w, string l) : web_root(w), local_root(l)
{
    curl = curl_easy_init();
    reset();
}

WebDavClient::~WebDavClient()
{
    curl_easy_cleanup(this->curl);
}

void WebDavClient::reset()
{
    curl_easy_reset(this->curl);
    curl_easy_setopt(this->curl, CURLOPT_USERAGENT, "3DavSync 0.1.0");
    curl_easy_setopt(this->curl, CURLOPT_CONNECTTIMEOUT, 50L);
    curl_easy_setopt(this->curl, CURLOPT_FOLLOWLOCATION, 1L);
    curl_easy_setopt(this->curl, CURLOPT_FAILONERROR, 1L);
    curl_easy_setopt(this->curl, CURLOPT_NOPROGRESS, 1L);
    curl_easy_setopt(this->curl, CURLOPT_SSL_VERIFYPEER, 0L);
    curl_easy_setopt(this->curl, CURLOPT_PIPEWAIT, 1L);
    // curl_easy_setopt(this->curl, CURLOPT_VERBOSE, 1L);
    if (this->use_basic_auth)
    {
        curl_easy_setopt(this->curl, CURLOPT_USERNAME, this->username.c_str());
        curl_easy_setopt(this->curl, CURLOPT_PASSWORD, this->password.c_str());
        curl_easy_setopt(this->curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
    }
}

void WebDavClient::set_basic_auth(std::string username, std::string password)
{
    this->username = username;
    this->password = password;
    this->use_basic_auth = true;
    this->reset();
}

string formulate_actual_url(string &root, string &rel_path)
{
    if (!rel_path.empty())
    {
        string escaped_string = curl_easy_escape(NULL, rel_path.c_str(), 0);
        string escaped_string_with_slash = regex_replace(escaped_string, regex("%2F"), "/");
        string res = root + escaped_string_with_slash;
        return res;
    }
    else
    {
        return root;
    }
}

bool WebDavClient::mkcol(string web_rel_path, optional<u64> mtime)
{
    string actual_url = formulate_actual_url(this->web_root, web_rel_path);
    // Test if directory existed already
    curl_easy_setopt(this->curl, CURLOPT_URL, actual_url.c_str());
    curl_easy_setopt(this->curl, CURLOPT_NOBODY, 1L);
    CURLcode head_res = curl_easy_perform(this->curl);
    if (head_res == CURLE_OK)
    {
        this->reset();
        return true;
    }

    this->reset();
    curl_easy_setopt(this->curl, CURLOPT_CUSTOMREQUEST, "MKCOL");
    curl_easy_setopt(this->curl, CURLOPT_URL, actual_url.c_str());
    if (mtime)
    {
        u64 actual_mtime = mtime.value();
        struct curl_slist *list = NULL;
        string oc_mtime = string("X-OC-Mtime: " + to_string(actual_mtime)).c_str();
        list = curl_slist_append(list, oc_mtime.c_str());
        curl_easy_setopt(this->curl, CURLOPT_HTTPHEADER, list);
    }

    CURLcode curl_res = curl_easy_perform(this->curl);
    if (curl_res != CURLE_OK)
    {
        long response_code;
        curl_easy_getinfo(this->curl, CURLINFO_RESPONSE_CODE, &response_code);
        printf("curl MKCOL failed: %s (%d)\n", curl_easy_strerror(curl_res), curl_res);
        printf("Location: %s\n", actual_url.c_str());
        printf("Response code: %ld\n", response_code);
        consoleUpdate(NULL);
        this->reset();
        return false;
    }
    else
    {
        this->reset();
        return true;
    }
}

bool WebDavClient::pull(string path, string web_rel_path)
{
    const char *c_path = path.c_str();
    if (this->curl)
    {
        // Formulate and fill actual url
        string actual_url = formulate_actual_url(this->web_root, web_rel_path);
        curl_easy_setopt(curl, CURLOPT_URL, actual_url.c_str());

        // Open a file at that path, overwrite if exists
        FILE *fp = fopen(c_path, "w");
        if (fp)
        {
            curl_easy_setopt(this->curl, CURLOPT_WRITEDATA, fp);
            CURLcode res = curl_easy_perform(curl);
            fclose(fp);
            if (res != 0)
            {
                long response_code;
                curl_easy_getinfo(this->curl, CURLINFO_RESPONSE_CODE, &response_code);
                printf("error getting file %s: %s\n", c_path, curl_easy_strerror(res));
                printf("Location: %s\n", actual_url.c_str());
                printf("Response code: %ld\n", response_code);
                consoleUpdate(NULL);
                this->reset();
                return false;
            }
        }
        else
        {
            printf("can't open %s for writing: %s\n", c_path, strerror(errno));
            consoleUpdate(NULL);
        }
    }
    else
    {
        printf("can't initalize curl!\n");
        consoleUpdate(NULL);
    }
    this->reset();
    return true;
}

static int seek_helper(void *userp, curl_off_t offset, int origin)
{
    FILE *fp = (FILE *)userp;

    if (-1 == fseek(fp, (long)offset, origin))
        /* couldn't seek */
        return CURL_SEEKFUNC_CANTSEEK;

    return CURL_SEEKFUNC_OK; /* success! */
}

bool WebDavClient::push(string path, string web_rel_path)
{
    const char *c_path = path.c_str();
    if (this->curl)
    {
        // Formulate and fill actual url
        string actual_url = formulate_actual_url(this->web_root, web_rel_path);
        curl_easy_setopt(curl, CURLOPT_URL, actual_url.c_str());

        // Open a file at that path to read
        FILE *fp = fopen(c_path, "r");
        if (fp)
        {
            // Read file metadata
            struct stat file_info;
            fstat(fileno(fp), &file_info);
            // Set curl reading stuff
            curl_easy_setopt(this->curl, CURLOPT_READDATA, fp);
            curl_easy_setopt(this->curl, CURLOPT_SEEKFUNCTION, seek_helper);
            // Prepare the headers
            // For Nextcloud/ownCloud, we can ask the server to use our mtime
            u64 mtime;
            struct stat attr;
            stat(path.c_str(), &attr);
            mtime = attr.st_mtime;

            struct curl_slist *list = NULL;
            string t = string("X-OC-Mtime: " + to_string(mtime)).c_str();
            list = curl_slist_append(list, t.c_str());
            curl_easy_setopt(this->curl, CURLOPT_HTTPHEADER, list);
            // We are uploading!
            curl_easy_setopt(this->curl, CURLOPT_UPLOAD, 1L);
            curl_easy_setopt(this->curl, CURLOPT_INFILESIZE, (curl_off_t)file_info.st_size);
            CURLcode res = curl_easy_perform(curl);
            fclose(fp);
            if (res != CURLE_OK)
            {
                long response_code;
                curl_easy_getinfo(this->curl, CURLINFO_RESPONSE_CODE, &response_code);
                printf("error pushing file %s: %s\n", c_path, curl_easy_strerror(res));
                printf("Location: %s\n", actual_url.c_str());
                printf("Response code: %ld\n", response_code);
                consoleUpdate(NULL);
                this->reset();
                return false;
            }
        }
        else
        {
            printf("can't open %s for writing: %s\n", c_path, strerror(errno));
            consoleUpdate(NULL);
        }
    }
    else
    {
        printf("can't initalize curl!\n");
        consoleUpdate(NULL);
    }

    this->reset();
    return true;
}

/// Write the curl response to a std::string
size_t curl_write_to_string(void *ptr, size_t size, size_t nmemb,
                            string *s)
{
    s->append(static_cast<char *>(ptr), size * nmemb);
    return size * nmemb;
}

optional<vector<FileEntry>> normalize_filelist(optional<vector<FileEntry>> i)
{
    if (i)
    {
        auto files = i.value();
        if (files.empty())
        {
            return nullopt;
        }
        else if (files.size() == 1)
        {
            // Only contains the root directory, we don't care about that
            files.erase(files.begin());
        }
        else if (files.size() > 1)
        {
            // Seems to be a query on collection
            // Get root first
            if (files[0].path.back() == '/')
            {
                string root = files[0].path.c_str();
                root.pop_back();
                for (FileEntry &file : files)
                {
                    file.path.erase(0, root.length());
                }
            }
        }
        return files;
    }
    else
    {
        return nullopt;
    }
}

const char *query = R"(<?xml version="1.0"?>
<d:propfind  xmlns:d="DAV:" xmlns:oc="http://owncloud.org/ns" xmlns:nc="http://nextcloud.org/ns">
 <d:prop>
  <d:getlastmodified />
  <d:getcontentlength />
  <d:resourcetype />
  <oc:checksums />
 </d:prop>
</d:propfind>)";

/// Read the timestamp from WebDAV server
optional<vector<FileEntry>> WebDavClient::get_remote_files()
{
    // Use PROPFIND to fetch file metadata
    if (this->curl)
    {
        string response = "";
        // Formulate and fill url
        curl_easy_setopt(curl, CURLOPT_URL, this->web_root.c_str());
        // Read XML content
        curl_easy_setopt(this->curl, CURLOPT_CUSTOMREQUEST, "PROPFIND");
        curl_easy_setopt(this->curl, CURLOPT_WRITEFUNCTION, curl_write_to_string);
        curl_easy_setopt(this->curl, CURLOPT_WRITEDATA, &response);
        curl_easy_setopt(this->curl, CURLOPT_POSTFIELDS, query);
        struct curl_slist *list = NULL;
        list = curl_slist_append(list, "Depth: infinity");
        curl_easy_setopt(this->curl, CURLOPT_HTTPHEADER, list);

        CURLcode curl_res = curl_easy_perform(this->curl);
        if (curl_res != CURLE_OK)
        {
            long response_code;
            curl_easy_getinfo(this->curl, CURLINFO_RESPONSE_CODE, &response_code);
            printf("curl PROPFIND failed: %s (%d)\n", curl_easy_strerror(curl_res), curl_res);
            printf("Response code: %ld\n", response_code);
            consoleUpdate(NULL);
            this->reset();
            return nullopt;
        }
        this->reset();

        // Now read it!
        XMLDocument doc;
        XMLError parse_res = doc.Parse(response.c_str());

        vector<FileEntry> res;
        if (parse_res == tinyxml2::XML_SUCCESS)
        {
            XMLElement *root = doc.RootElement();
            for (XMLElement *e = root->FirstChildElement(); e != NULL; e = e->NextSiblingElement())
            {
                string path;
                time_t time;
                bool folder = false;
                int size;
                // Get file path
                if (e->FirstChildElement("d:href"))
                {
                    const char *text = e->FirstChildElement("d:href")->GetText();
                    // The path here is escaped. Convert them back to unescaped form
                    char *decoded = curl_easy_unescape(this->curl, text, 0, NULL);
                    path = string(decoded);
                }
                else
                {
                    printf("malformed WebDAV response: missing d:href in PROPFIND\n");
                    consoleUpdate(NULL);
                    return nullopt;
                }
                if (e->FirstChildElement("d:propstat"))
                {
                    if (e->FirstChildElement("d:propstat")->FirstChildElement("d:prop"))
                    {
                        XMLElement *prop = e->FirstChildElement("d:propstat")->FirstChildElement("d:prop");
                        if (prop->FirstChildElement("d:getlastmodified"))
                        {
                            string time_str = prop->FirstChildElement("d:getlastmodified")->GetText();
                            time = curl_getdate(time_str.c_str(), NULL);
                        }
                        else
                        {
                            printf("malformed WebDAV response: missing d:getlastmodified in PROPFIND\n");
                            consoleUpdate(NULL);
                            return nullopt;
                        }
                        if (prop->FirstChildElement("d:getcontentlength"))
                        {
                            string size_str = prop->FirstChildElement("d:getcontentlength")->GetText();
                            size = stoi(size_str);
                        }
                        else
                        {
                            size = 0;
                        }
                        if (prop->FirstChildElement("d:resourcetype") && prop->FirstChildElement("d:resourcetype")->FirstChildElement("d:collection"))
                        {
                            folder = true;
                        }
                    }
                    else
                    {
                        printf("malformed WebDAV response: missing d:prop in PROPFIND\n");
                        consoleUpdate(NULL);
                        return nullopt;
                    }
                }
                else
                {
                    printf("malformed WebDAV response: missing d:propstat in PROPFIND\n");
                    consoleUpdate(NULL);
                    return nullopt;
                }

                res.push_back(FileEntry{path, time, folder, size});
            }
        }
        else
        {
            printf("malformed XML response: %d\n", parse_res);
            consoleUpdate(NULL);
            return nullopt;
        }
        // Turn file paths into canonical form
        auto out = normalize_filelist(res);
        return out;
    }
    else
    {
        printf("can't initalize curl!\n");
        consoleUpdate(NULL);
        return nullopt;
    }
}

optional<FileEntry> get_file(vector<FileEntry> *files, string path)
{
    for (unsigned i = 0; i < files->size(); i++)
    {
        if ((*files)[i].path == path)
        {
            FileEntry f = (*files)[i];
            files->erase(files->begin() + i);
            return f;
        }
    }
    return nullopt;
}

vector<pair<string, bool>> recursively_get_dir(string base_path, string ext_path = "")
{
    vector<pair<string, bool>> paths;

    DIR *dir;
    struct dirent *ent;
    string path = base_path + ext_path;
    if ((dir = opendir(path.c_str())) != NULL)
    {
        paths.push_back(pair(ext_path + "/", true));
        while ((ent = readdir(dir)) != NULL)
        {
            vector<pair<string, bool>> subdir = recursively_get_dir(base_path, ext_path + "/" + ent->d_name);
            paths.insert(paths.end(), subdir.begin(), subdir.end());
        }
    }
    else
    {
        if (ext_path != "")
        {
            paths.push_back(make_pair(ext_path, false));
        }
        else
        {
            printf("directory %s not found\n", path.c_str());
            consoleUpdate(NULL);
        }
    }
    closedir(dir);
    return paths;
}

bool user_confirm()
{
    PadState pad;
    while (appletMainLoop())
    {
        padUpdate(&pad);
        u32 kDown = padGetButtonsDown(&pad);
        if (kDown & HidNpadButton_A)
        {
            return true;
        }
        else if (kDown & HidNpadButton_B)
        {
            return false;
        }
    }
    return false;
}

bool WebDavClient::compareAndUpdate()
{
    bool success = true;

    struct stat rootstat;
    if (!stat(this->local_root.c_str(), &rootstat))
    {
        // Create directory
        mkdir(this->local_root.c_str(), 0777);
    }
    else if (!S_ISDIR(rootstat.st_mode))
    {
        printf(CONSOLE_RED "specified local dir is not a dir!" CONSOLE_RESET);
        consoleUpdate(NULL);
        return false;
    }

    this->mkcol("", nullopt);

    optional<vector<FileEntry>> remote_files_optional = this->get_remote_files();
    if (!remote_files_optional)
    {
        printf("failed to fetch remote file list\n");
        consoleUpdate(NULL);
        return false;
    }

    vector<FileEntry> remote_files = remote_files_optional.value();
    vector<pair<string, bool>> local_files = recursively_get_dir(this->local_root);
    for (auto [path, is_dir] : local_files)
    {
        string local_real_path = this->local_root + path;
        time_t local_mtime;
        struct stat attr;
        stat(local_real_path.c_str(), &attr);
        local_mtime = attr.st_mtime;
        // fsdev_getmtime(local_real_path.c_str(), &local_mtime);

        optional<FileEntry> remote_file_optional = get_file(&remote_files, path);
        if (remote_file_optional)
        {
            FileEntry remote_file = remote_file_optional.value();

            if (is_dir)
            {
                // Local && Remote directory exists, we are fine
            }
            else if (local_mtime > remote_file.last_modified)
            {
                // Ask if we should do an upload
                printf("\n%s", path.c_str());
                printf(CONSOLE_YELLOW "Local version newer on above file.\n" CONSOLE_RESET);
                printf(CONSOLE_YELLOW "Upload (A) or Not (B)?\n" CONSOLE_RESET);
                consoleUpdate(NULL);
                if (user_confirm())
                {
                    // Upload local version
                    printf("%s: local modified, uploading...\n\n", path.c_str());
                    consoleUpdate(NULL);
                    if (!this->push(local_real_path, path))
                    {
                        printf(CONSOLE_RED "%s: local modified, upload failed.\n", path.c_str());
                        printf(CONSOLE_RESET);
                        consoleUpdate(NULL);
                        success = false;
                    }
                }
            }
            else if (local_mtime < remote_file.last_modified)
            {
                // Ask if we should do an upload
                printf("\n%s", path.c_str());
                printf(CONSOLE_YELLOW "Local version older on above file.\n" CONSOLE_RESET);
                printf(CONSOLE_YELLOW "Download (A) or Not (B)?\n" CONSOLE_RESET);
                consoleUpdate(NULL);
                // Pull remote version
                if (user_confirm())
                {
                    printf("%s: remote modified, downloading...\n\n", remote_file.path.c_str());
                    consoleUpdate(NULL);
                    if (!this->pull(local_real_path, remote_file.path))
                    {
                        printf(CONSOLE_RED "%s: remote modified, download failed.\n", path.c_str());
                        printf(CONSOLE_RESET);
                        consoleUpdate(NULL);
                        success = false;
                    }
                }
            }
            else
            {
                // Identical, don't do anything
            }
        }
        else
        {
            // Remote file DNE, upload local version
            if (is_dir)
            {
                this->mkcol(path, local_mtime);
            }
            else
            {
                printf("%s: new local file, uploading...\n\n", path.c_str());
                consoleUpdate(NULL);
                if (!this->push(local_real_path, path))
                {
                    printf(CONSOLE_RED "%s: upload failed.\n\n", path.c_str());
                    printf(CONSOLE_RESET);
                    consoleUpdate(NULL);
                    success = false;
                }
                else
                {
                }
            }
        }
    }
    // Pull the remaining remote files
    for (FileEntry remote_file : remote_files)
    {
        string real_local_path = this->local_root + remote_file.path;
        if (remote_file.path == "/")
        {
            continue;
        }
        else if (remote_file.folder)
        {
            int status = mkdir(real_local_path.c_str(), 0777);
            if (status != 0)
            {
                printf("can't create local dir %s: %s\n", real_local_path.c_str(), strerror(errno));
                consoleUpdate(NULL);
                success = false;
            }
        }
        else
        {
            // It's a file

            printf("%s: new remote file, downloading...\n\n", remote_file.path.c_str());
            consoleUpdate(NULL);
            if (!this->pull(real_local_path, remote_file.path))
            {
                printf("can't download remote file %s\n", remote_file.path.c_str());
                consoleUpdate(NULL);
                success = false;
            }
            else
            {
            }
        }
    }
    return success;
}