#include "web_server.h"

namespace config {
  // Values should be defined in config.h
#ifdef HTTP_USER
  const char *http_user = HTTP_USER;
#else
  const char *http_user = "";
#endif
#ifdef HTTP_PASSWORD
  const char *http_password = HTTP_PASSWORD;
#else
  const char *http_password = "";
#endif

}

namespace web_server {

  const char *header_template;
  const char *body_template;
  const char *script_template;
  void handleWebServerRoot();
  void handleWebServerCSV();
  void handlePageNotFound();
  void handleDeleteCSV();

#if defined(ESP8266)
  ESP8266WebServer http(80); // Create a webserver object that listens for HTTP request on port 80
#endif
#if defined(ESP32)
  WebServer http(80);
#endif

  void update() {
    http.handleClient(); // Listen for HTTP requests from clients
  }

  void initialize() {
    header_template =
        PSTR("<!doctype html><html lang=en>"
            "<head>\n"
            "<title>%d ppm - CO2 SENSOR - %s - %s</title>\n"
            "<meta charset='UTF-8'>"
            // HfT Favicon
            "<link rel='icon' type='image/png' sizes='16x16' href='data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABHNCSVQICAgIfAhkiAAAAHtJREFUOE9jvMnA+5+BAsBIFQMkl85h+P3kGcOb8jqwW+TPH2H4de0GA29UGNxtfx49YWCRk0HwHz5iuKegwwB2AS4DkA2F6VR6cAWsEQbgBqDY9vARw/ejJ+Au+LxsFcPz6BSwHpwGYPMCSS6gyAAKYhESiKMGjPgwAADopHVhn5ynEwAAAABJRU5ErkJggg=='/>"
            // Responsive grid:
            "<link rel='stylesheet' href='https://unpkg.com/purecss@2.0.3/build/pure-min.css'>\n"
            "<link rel='stylesheet' href='https://unpkg.com/purecss@2.0.3/build/grids-responsive-min.css'>\n"
            // JS Graphs:
            "<script src='https://cdn.plot.ly/plotly-basic-1.58.2.min.js'></script>\n"
            // Fullscreen
            "<meta name='viewport' content='width=device-width, initial-scale=1'>\n"
            // Refresh after every measurement.
            // "<meta http-equiv='refresh' content='%d'>\n"
            "</head>\n"
            "<body>\n"

            "<div class='pure-g'><div class='pure-u-1'><div class='pure-menu'><p class='pure-menu-heading'>HfT-Stuttgart CO<sub>2</sub> sensor</p></div></div>\n"
            "<div class='pure-u-1'><ul class='pure-menu pure-menu-horizontal pure-menu-list'>\n"
            "<li class='pure-menu-item'><a href='#graph' class='pure-menu-link'>Graph</a></li>\n"
            "<li class='pure-menu-item'><a href='#table' class='pure-menu-link'>Info</a></li>\n"
            "<li class='pure-menu-item'><a href='#log' class='pure-menu-link'>Log</a></li>\n"
            "<li class='pure-menu-item'><a href='./%s' class='pure-menu-link'>Download CSV</a></li>\n"
            "</ul></div></div>\n");

    body_template =
        PSTR("<div class='pure-g'>\n"
            "<div class='pure-u-1' id='graph'></div>\n" // Graph placeholder
            "</div>\n"
            "<div class='pure-g'>\n"
            //Sensor table
            "<table id='table' class='pure-table-striped pure-u-1 pure-u-md-1-2'>\n"
            "<tr><th>Sensor</th><th>%s</th></tr>\n"
            "<tr><td>CO<sub>2</sub> concentration</td><td>%5d ppm</td></tr>\n"
            "<tr><td>Temperature</td><td>%.1f&#8451;</td></tr>\n"
            "<tr><td>Humidity</td><td>%.1f%%</td></tr>\n"
            "<tr><td>Last measurement</td><td>%s</td></tr>\n"
            "<tr><td>Measurement timestep</td><td>%5d s</td></tr>\n"
            "<tr><td>Last CSV write</td><td>%s</td></tr>\n"
            "<tr><td>CSV timestep</td><td>%5d s</td></tr>\n"
#ifdef MQTT
            "<tr><td>Last MQTT publish</td><td>%s</td></tr>\n"
            "<tr><td>MQTT publish timestep</td><td>%5d s</td></tr>\n"
#endif
            "<tr><td>Temperature offset</td><td>%.1fK</td></tr>\n"
            "<tr><td>Local address</td><td><a href='http://%s.local/'>%s.local</a></td></tr>\n"
            "<tr><td>Local IP</td><td><a href='http://%s'>%s</a></td></tr>\n"
            "<tr><td>Free heap space</td><td>%6d bytes</td></tr>\n"
            "<tr><td>Available drive space</td><td>%d kB</td></tr>\n"
            "<tr><td>Max loop duration</td><td>%5d ms</td></tr>\n"
            "<tr><td>Board</td><td>%s</td></tr>\n"
            "<tr><td>Uptime</td><td>%4d h %02d min %02d s</td></tr>\n"
            "</table>\n"
            // CSV placeholder
            "<div id='log' class='pure-u-1 pure-u-md-1-2'></div>\n"
            "<form action='/delete_csv' method='POST' onsubmit=\"return confirm('Are you really sure you want to delete all data?') && (document.body.style.cursor = 'wait');\">"
            "<input type='submit' value='Delete CSV'/>"
            "</form>\n"
            "</div>\n");

    script_template = PSTR("<script>\n"
        "document.body.style.cursor = 'default';\n"
        "fetch('./%s',{credentials:'include'})\n"
        // Get CSV, fill table and fill diagram
        ".then(response=>response.text())\n"
        ".then(csvText=>csvToTable(csvText))\n"
        ".then(htmlTable=>addLogTableToPage(htmlTable))\n"
        ".then(_=>Plotly.newPlot('graph',data,layout,{displaylogo:false}))\n"
        ".catch(e=>console.error(e));\n"
        "xs=[];\n"
        "data=[{x:xs,y:[],type:'scatter',name:'CO<sub>2</sub>',line:{color:'#2ca02c'}},\n"
        "{x:xs,y:[],type:'scatter',name:'Temperature',yaxis:'y2',line:{color:'#ff7f0e',dash:'dot'}},\n"
        "{x:xs,y:[],type:'scatter',name:'Humidity',yaxis:'y3',line:{color:'#1f77b4',dash:'dot'}}];\n"
        "layout={height:600,title:'%s',legend:{xanchor:'right',x:0.2,y:1.0},\n"
        "xaxis:{domain:[0.0,0.85]},yaxis:{ticksuffix:'ppm',range:[0,2000],dtick:200},\n"
        "yaxis2:{overlaying:'y',side:'right',ticksuffix:'°C',position:0.9,anchor:'free',range:[0,30],dtick:3},\n"
        "yaxis3:{overlaying:'y',side:'right',ticksuffix:'%%',position:0.95,anchor:'free',range:[0,100],dtick:10}\n"
        "};\n"
        "function csvToTable(csvText) {\n"
        "csvText=csvText.trim();\n"
        "lines=csvText.split('\\n');\n"
        "table=document.createElement('table');\n"
        "table.className='pure-table-striped';\n"
        "n=lines.length;\n"
        "lines.forEach((line,i)=>{\n"
        "fields=line.split(';');\n"
        "xs.push(fields[0]);\n"
        "data[0]['y'].push(fields[1]);\n"
        "data[1]['y'].push(fields[2]);\n"
        "data[2]['y'].push(fields[3]);\n"
        "if(i>4 && i<n-12){if(i==5){fields=['...','...','...','...']}else{return;}}\n"
        "row=document.createElement('tr');\n"
        "fields.forEach((field,index)=>{\n"
        "cell=document.createElement(i<2?'th':'td');\n"
        "cell.appendChild(document.createTextNode(field));\n"
        "row.appendChild(cell);});\n"
        "table.appendChild(row);});\n"
        "return table;}\n"
        "function addLogTableToPage(table){document.getElementById('log').appendChild(table);}\n"
        "</script>\n"
        "</body>\n"
        "</html>");

    // Web-server
    http.on("/", handleWebServerRoot);
    http.on("/" + csv_writer::filename, handleWebServerCSV);
    http.on("/delete_csv", HTTP_POST, handleDeleteCSV);
    http.onNotFound(handlePageNotFound);
    http.begin();

    Serial.print(F("You can access this sensor via http://"));
    Serial.print(SENSOR_ID);
    Serial.print(F(".local (might be unstable) or http://"));
    Serial.println(WiFi.localIP());
  }

  // Allow access if http_user or http_password are empty, or if provided credentials match
  bool shouldBeAllowed() {
    return strcmp(config::http_user, "") == 0 || strcmp(config::http_password, "") == 0
        || http.authenticate(config::http_user, config::http_password);
  }

  void handleWebServerRoot() {
    if (!shouldBeAllowed()) {
      return http.requestAuthentication(DIGEST_AUTH);
    }

    unsigned long ss = seconds();
    unsigned int hh = ss / 3600;
    ss -= hh * 3600;
    uint8_t mm = ss / 60;
    ss -= mm * 60;
    uint16_t available_fs_space = csv_writer::getAvailableSpace() / 1024;

    //NOTE: Splitting in multiple parts in order to use less RAM
    char content[2000]; // Update if needed
    // Header size : 1383 - Body size : 1246 - Script size : 1648
    // Header
    snprintf_P(content, sizeof(content), header_template, sensor::co2, SENSOR_ID.c_str(),
        WiFi.localIP().toString().c_str(), csv_writer::filename.c_str());

    http.setContentLength(CONTENT_LENGTH_UNKNOWN);
    http.send_P(200, PSTR("text/html"), content);

    // Body
    snprintf_P(content, sizeof(content), body_template, SENSOR_ID.c_str(), sensor::co2, sensor::temperature,
        sensor::humidity, sensor::timestamp.c_str(), config::measurement_timestep,
        csv_writer::last_successful_write.c_str(), config::csv_interval,
#ifdef MQTT
        mqtt::last_successful_publish.c_str(), config::sending_interval,
#endif
        config::temperature_offset, SENSOR_ID.c_str(), SENSOR_ID.c_str(), WiFi.localIP().toString().c_str(),
        WiFi.localIP().toString().c_str(), get_free_heap_size(), available_fs_space, max_loop_duration, BOARD, hh, mm,
        ss);

    http.sendContent(content);

    // Script
    snprintf_P(content, sizeof(content), script_template, csv_writer::filename.c_str(), SENSOR_ID.c_str());

    http.sendContent(content);
  }

  void handleWebServerCSV() {
    if (!shouldBeAllowed()) {
      return http.requestAuthentication(DIGEST_AUTH);
    }
    if (FS_LIB.exists(csv_writer::filename)) {
      fs::File csv_file = FS_LIB.open(csv_writer::filename, "r");
      http.sendHeader("Content-Length", String(csv_file.size()));
      http.streamFile(csv_file, F("text/csv"));
      csv_file.close();
    } else {
      http.send(204, F("text/html"), F("No data available."));
    }
  }

  void handleDeleteCSV() {
    if (!shouldBeAllowed()) {
      return http.requestAuthentication(DIGEST_AUTH);
    }
    Serial.print("Removing CSV file...");
    FS_LIB.remove(csv_writer::filename);
    Serial.println(" Done!");
    http.sendHeader("Location", "/");
    http.send(303);
  }

  void handlePageNotFound() {
    http.send(404, F("text/plain"), F("404: Not found"));
  }
}