/*
 * SDWebBrowse.ino
 *
 * This sketch uses the microSD card slot on the a WIZ5500 Ethernet shield
 * to serve up files over a very minimal browsing interface
 *
 * Some code is from Bill Greiman's SdFatLib examples, some is from the
 * Arduino Ethernet WebServer example and the rest is from Limor Fried
 * (Adafruit) so its probably under GPL
 *
 * Tutorial is at https://learn.adafruit.com/arduino-ethernet-sd-card/serving-files-over-ethernet
 * 
 */
 
#include <SPI.h>
#include <SD.h>
#include <Ethernet2.h>
 
/************ ETHERNET STUFF ************/
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };  // change if necessary
byte ip[] = { 192, 168, 1, 177 };                     // change if necessary
EthernetServer server(80);
 
/************ SDCARD STUFF ************/
#define SDCARD_CS 4
File root;
 
#if defined(ESP8266)
  // default for ESPressif
  #define WIZ_CS 15
#elif defined(ESP32)
  #define WIZ_CS 33
#elif defined(ARDUINO_STM32_FEATHER)
  // default for WICED
  #define WIZ_CS PB4
#elif defined(TEENSYDUINO)
  #define WIZ_CS 10
#elif defined(ARDUINO_FEATHER52)
  #define WIZ_CS 11
#else   // default for 328p, 32u4 and m0
  #define WIZ_CS 10
#endif
 
// store error strings in flash to save RAM
#define error(s) error_P(PSTR(s))
 
void error_P(const char* str) {
  Serial.print(F("error: "));
  Serial.println(str);
 
  while(1);
}
 
void setup() {
  Serial.begin(115200);
  while (!Serial);      // For 32u4 based microcontrollers like 32u4 Adalogger Feather
 
  //Serial.print(F("Free RAM: ")); Serial.println(FreeRam());  
 
  if (!SD.begin(SDCARD_CS)) {
    error("card.init failed!");
  } 
  
  root = SD.open("/");
  printDirectory(root, 0);
  
  // Recursive list of all directories
  Serial.println(F("Files found in all dirs:"));
  printDirectory(root, 0);
  
  Serial.println();
  Serial.println(F("Done"));
  
  // Debugging complete, we start the server!
  Serial.println(F("Initializing WizNet"));
  Ethernet.init(WIZ_CS);
  // give the ethernet module time to boot up
  delay(1000);
  // start the Ethernet connection
  // Use the fixed IP specified. If you want to use DHCP first
  //   then switch the Ethernet.begin statements
  Ethernet.begin(mac, ip);
  // try to congifure using DHCP address instead of IP:
  //  Ethernet.begin(mac);
  
  // print the Ethernet board/shield's IP address to Serial monitor
  Serial.print(F("My IP address: "));
  Serial.println(Ethernet.localIP());
 
  server.begin();
}
 
void ListFiles(EthernetClient client, uint8_t flags, File dir) {
  client.println("<ul>");
  while (true) {
    File entry = dir.openNextFile();
   
    // done if past last used entry
     if (! entry) {
       // no more files
       break;
     }
 
    // print any indent spaces
    client.print("<li><a href=\"");
    client.print(entry.name());
    if (entry.isDirectory()) {
       client.println("/");
    }
    client.print("\">");
    
    // print file name with possible blank fill
    client.print(entry.name());
    if (entry.isDirectory()) {
       client.println("/");
    }
        
    client.print("</a>");
/*
    // print modify date/time if requested
    if (flags & LS_DATE) {
       dir.printFatDate(p.lastWriteDate);
       client.print(' ');
       dir.printFatTime(p.lastWriteTime);
    }
    // print size if requested
    if (!DIR_IS_SUBDIR(&p) && (flags & LS_SIZE)) {
      client.print(' ');
      client.print(p.fileSize);
    }
    */
    client.println("</li>");
    entry.close();
  }
  client.println("</ul>");
}
 
// How big our line buffer should be. 100 is plenty!
#define BUFSIZ 100
 
void loop()
{
  char clientline[BUFSIZ];
  char name[17];
  int index = 0;
  
  EthernetClient client = server.available();
  if (client) {
    // an http request ends with a blank line
    boolean current_line_is_blank = true;
    
    // reset the input buffer
    index = 0;
    
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        
        // If it isn't a new line, add the character to the buffer
        if (c != '\n' && c != '\r') {
          clientline[index] = c;
          index++;
          // are we too big for the buffer? start tossing out data
          if (index >= BUFSIZ) 
            index = BUFSIZ -1;
          
          // continue to read more data!
          continue;
        }
        
        // got a \n or \r new line, which means the string is done
        clientline[index] = 0;
        
        // Print it out for debugging
        Serial.println(clientline);
        
        // Look for substring such as a request to get the file
        if (strstr(clientline, "GET /") != 0) {
          // this time no space after the /, so a sub-file!
          char *filename;
          
          filename = clientline + 5; // look after the "GET /" (5 chars)  *******
          // a little trick, look for the " HTTP/1.1" string and 
          // turn the first character of the substring into a 0 to clear it out.
          (strstr(clientline, " HTTP"))[0] = 0;
 
          if(filename[strlen(filename)-1] == '/') {  // Trim a directory filename
            filename[strlen(filename)-1] = 0;        //  as Open throws error with trailing /
          }
          
          Serial.print(F("Web request for: ")); Serial.println(filename);  // print the file we want
 
          File file = SD.open(filename, O_READ);
          if ( file == 0 ) {  // Opening the file with return code of 0 is an error in SDFile.open
            client.println("HTTP/1.1 404 Not Found");
            client.println("Content-Type: text/html");
            client.println();
            client.println("<h2>File Not Found!</h2>");
            client.println("<br><h3>Couldn't open the File!</h3>");
            break; 
          }
          
          Serial.println("File Opened!");
                    
          client.println("HTTP/1.1 200 OK");
          if (file.isDirectory()) {
            Serial.println("is a directory");
            //file.close();
            client.println("Content-Type: text/html");
            client.println();
            client.print("<h2>Files in /");
            client.print(filename); 
            client.println(":</h2>");
            ListFiles(client,LS_SIZE,file);  
            file.close();                   
          } else { // Any non-directory clicked, server will send file to client for download
            client.println("Content-Type: application/octet-stream");
            client.println();
          
            char file_buffer[16];
            int avail;
            while (avail = file.available()) {
              int to_read = min(avail, 16);
              if (to_read != file.read(file_buffer, to_read)) {
                break;
              }
              // uncomment the serial to debug (slow!)
              //Serial.write((char)c);
              client.write(file_buffer, to_read);
            }
            file.close();
          }
        } else {
          // everything else is a 404
          client.println("HTTP/1.1 404 Not Found");
          client.println("Content-Type: text/html");
          client.println();
          client.println("<h2>File Not Found!</h2>");
        }
        break;
      }
    }
    // give the web browser time to receive the data
    delay(1);
    client.stop();
  }
}
 
 
void printDirectory(File dir, int numTabs) {
   while(true) {
     File entry =  dir.openNextFile();
     if (! entry) {
       // no more files
       break;
     }
     for (uint8_t i=0; i<numTabs; i++) {
       Serial.print('\t');
     }
     Serial.print(entry.name());
     if (entry.isDirectory()) {
       Serial.println("/");
       printDirectory(entry, numTabs+1);
     } else {
       // files have sizes, directories do not
       Serial.print("\t\t");
       Serial.println(entry.size(), DEC);
     }
     entry.close();
   }
}