/* Copyright (c) 2014 Sam Sykes, Gordon Williams. See the file LICENSE for copying permission. */
/* 
Module for the SSD1306 OLED controller in displays like the Crius CO-16
```
function go(){
 // write some text
 g.drawString("Hello World!",2,2);
 // write to the screen
 g.flip(); 
}
// I2C
I2C1.setup({scl:B6,sda:B7});

var g = require("SSD1306").connect(I2C1, go);
// or
var g = require("SSD1306").connect(I2C1, go, { address: 0x3C });
// or 
var g = connect(I2C1,start, { height : 48, width:64 });  // for 64x48 LCD
// or 
var g = connect(I2C1,start, { height : 32 });  // for 128x32 LCD

// SPI
var s = new SPI();
s.setup({mosi: B6, sck:B5});
var g = require("SSD1306").connectSPI(s, A8, B7, go);
```
*/
var C = {
 OLED_WIDTH                 : 128,
 OLED_CHAR                  : 0x40,
 OLED_CHUNK                 : 128
};

// commands sent when initialising the display
var extVcc=false; // if true, don't start charge pump 
var initCmds = new Uint8Array([ 
             0xAe, // 0 disp off
             0xD5, // 1 clk div
             0x80, // 2 suggested ratio
             0xA8, 63, // 3 set multiplex, height-1
             0xD3,0x0, // 5 display offset
             0x40, // 7 start line
             0x8D, extVcc?0x10:0x14, // 8 charge pump
             0x20,0x0, // 10 memory mode
             0xA1, // 12 seg remap 1
             0xC8, // 13 comscandec
             0xDA, 0x12, // 14 set compins, height==64 ? 0x12:0x02,
             0x81, extVcc?0x9F:0xCF, // 16 set contrast
             0xD9, extVcc?0x22:0xF1, // 18 set precharge
             0xDb, 0x40, // 20 set vcom detect
             0xA4, // 22 display all on
             0xA6, // 23 display normal (non-inverted)
             0xAf // 24 disp on
            ]);
// commands sent when sending data to the display
var flipCmds = [
     0x21, // columns
     0, C.OLED_WIDTH-1,
     0x22, // pages
     0, 7 /* (height>>3)-1 */];
function update(options) {
  if (options) {
    if (options.height) {
      initCmds[4] = options.height-1;
      initCmds[15] = options.height==64 || options.height==48 ? 0x12 : 0x02;
      flipCmds[5] = (options.height>>3)-1;
    }
    if (options.width) {
      C.OLED_WIDTH = options.width;
      flipCmds[1] = (128-options.width)/2; // 0x20 for 64, 0 for 128;
      flipCmds[2] = flipCmds[1]+options.width-1; // 0x5f;
    }
    if (options.contrast!==undefined) initCmds[17] = options.contrast;
  }
}


exports.connect = function(i2c, callback, options) {
  update(options);
  var oled = Graphics.createArrayBuffer(C.OLED_WIDTH,initCmds[4]+1,1,{vertical_byte : true, msb:false});

  var addr = 0x3C;
  if(options) {
    if (options.address) addr = options.address;  
    // reset display if 'rst' is part of options 
    if (options.rst) digitalPulse(options.rst, 0, 10); 
  }
  
  setTimeout(function() {
    // configure the OLED
    initCmds.forEach(function(d) {i2c.writeTo(addr, [0,d]);});
  }, 50);

  // if there is a callback, call it now(ish)
  if (callback !== undefined) setTimeout(callback, 100);

  // write to the screen
  oled.flip = function() { 
    // set how the data is to be sent (whole screen)
    flipCmds.forEach(function(d) {i2c.writeTo(addr, [0,d]);});
    var chunk = new Uint8Array(C.OLED_CHUNK+1);

    chunk[0] = C.OLED_CHAR;
    for (var p=0; p<this.buffer.length; p+=C.OLED_CHUNK) {
      chunk.set(new Uint8Array(this.buffer,p,C.OLED_CHUNK), 1);
      i2c.writeTo(addr, chunk);
    } 
  };

  // set contrast, 0..255
  oled.setContrast = function(c) { i2c.writeTo(addr, 0, 0x81, c); };

  // set off
  oled.off = function() { i2c.writeTo(addr, 0, 0xAE); }

  // set on
  oled.on = function() { i2c.writeTo(addr, 0, 0xAF); }

  // return graphics
  return oled;
};

exports.connectSPI = function(spi, dc,  rst, callback, options) {
  update(options);
  var cs = options?options.cs:undefined;
  var oled = Graphics.createArrayBuffer(C.OLED_WIDTH,initCmds[4]+1,1,{vertical_byte : true, msb:false});

  if (rst) digitalPulse(rst,0,10);
  setTimeout(function() {
    if (cs) digitalWrite(cs,0);
    // configure the OLED
    digitalWrite(dc,0); // command
    spi.write(initCmds);
    digitalWrite(dc,1); // data
    if (cs) digitalWrite(cs,10);
    // if there is a callback, call it now(ish)
    if (callback !== undefined) setTimeout(callback, 10);
  }, 50);

  // write to the screen
  oled.flip = function() { 
    // set how the data is to be sent (whole screen)
    if (cs) digitalWrite(cs,0);
    digitalWrite(dc,0);// command
    spi.write(flipCmds);
    digitalWrite(dc,1);// data
    spi.write(this.buffer);
    if (cs) digitalWrite(cs,1);
  };

  // set contrast, 0..255
  oled.setContrast = function(c) { 
    if (cs) cs.reset();
    spi.write(0x81,c,dc);
    if (cs) cs.set();
  };

  // set off
  oled.off = function() { 
    if (cs) cs.reset();
    spi.write(0xAE,dc);
    if (cs) cs.set();
  };

  // set on
  oled.on = function() { 
    if (cs) cs.reset();
    spi.write(0xAF,dc);
    if (cs) cs.set();
  };

  // return graphics
  return oled;
};