'use strict'

const Device = require('@uci/i2c').Device,
  portpin = require('./port-pin'), // classes for MCP port and pins
  EventEmitter = require('events'),
  _ = require('@uci/utils'),
  aggregate = require('aggregation/es6')

const
  Port = portpin.Port,
  pinConfigs = portpin.configs, // for export so pinConfigs can be accessed at runtime
  pause = _.pPause,
  debug = _.debug('mcp:23008-17')

class MCP23008 extends aggregate(Device, EventEmitter) {
  constructor(busObj, i2cAddress, opts = {}) {
    super(busObj, i2cAddress, opts)
    // opts could include options passed on to ports and pin  including custom pin config, pin ids...see gpio.js
    this.chip_config = opts.chip_config // TODO  allow opts.chip_config to be a byte instead of a string pointer
    this.ports = {}
    opts.portID = 'A'
    opts.pids = opts.pids ? opts.pids : opts.pidsA
    this.ports.A = new Port(opts)
    this.ports.A.state = new _.Byte(opts.stateA)
    this.ports.A.interrupt = opts.interruptA ? opts.interruptA : opts.interrupt
  } // end constructor

  // helpers
  pin(id) { return this.ports.A.pin(id) } // get a reference to a particular pin's object

  pid(address) { return this.ports.A.pid(address) } // return pin id for a given address on a port

  pid(num) { return this.ports.A.pins[num - 1].id }

  portByPin(id) {
    if (this.ports.A.pin(id)) { return 'A' }
    return false
  }

  state(port = 'A') {
    return this.ports[port].state.value
  }

  // get a handle to the ports interrupt
  inter(port = 'A') {
    return this.ports[port].interrupt
  }

  // Must call after instantiating.

  async init() {
    debug.L1(`\n=======\nInitializing ${this.id}`)
    await this.writeChipCfg(this.chip_config) // chip settings
    await this.writePinsCfg()
    // write out any initial  state(s)
    for (let port in this.ports) {
      if (this.state(port)) {
        debug.L1(`writing initial port state ${port} ${this.state(port)}`)
        await this.writePort(this.state(port), 'force', port)
      }
    }
  }

  // must call after init if using interrupts
  async start() {
    debug.L1(`starting ${ this.id }`)
    for (let port in this.ports) {
      // if there are interrupts being used then start them and listeners
      if (this.inter(port)) {
        this.startInterrupt(port)
      }
    }
  }

  async startInterrupt(port) {
    await this.interruptReset(port)
    debug.L1(`starting interrupt on port ${ port }`)
    await this.inter(port).start()
    let chip = this // scope `this` for use in the listener below
    // bind handler to the chip so handler can read/write to chip/bank when interrupt is emitted
    debug.L3('handler', this.inter(port).handler)
    let ihandler = this.inter(port).handler.bind(this)
    // inside the listener `this` is the interrupt not the chip/bank
    this.inter(port).on('fired', async function () {
      debug.L1(`interrupt from ${this.pin_number}`)
      let data = await ihandler(port)
      debug.L2(`port interrupt event 'fired' data => ${data.bank} on port ${data.port} pin# ${data.pin} pid ${data.pid}`)
      chip.emit('fired', data) // emit up the class chain
    })

  }

  async interruptReset(port = 'A') {
    await this.read(portReg(0x08, port))
    await pause(100) // give enough time for mcp to reset its interupt
    debug.L1(`interrupt reset on ${this.id} port ${port}`)
  }

  async interruptPin(port, format) {
    if ('AB'.indexOf(port) === -1) {
      format = port ? port : null
      port = 'A'
    }
    let result = await this.read(portReg(0x07, port))
    return format ? _.byteFormat(result, { in: 'DEC', out: format }) : result

  }

  async writeChipCfg(cfg = 'default') {
    let setting = chip_config[cfg]
    let byte = _.byteFormat(setting.val, { in: setting.fmt, out: 'DEC' })
    debug.L1(`writing mcp chip config ${setting.val}`)
    await this.write(chip_config.cmd, byte)
  }

  // pin configurations should already be set before calling
  async writePinsCfg() {
    debug.L1('writing mcp pins config')
    for (let port in this.ports) {
      for (let setting in registers.pin_config) {
        let reg = registers.pin_config[setting]
        // TODO 0x10 should be based on chip config
        let byte = 0
        for (let pin of this.ports[port].pins) {
          byte += pin.address * pin.cfg[setting]
          debug.L3(`port: ${ port } pin: ${pin.id} setting: ${ setting } reg: ${ reg } byte: ${ byte }`)
        }
        await this.write(portReg(reg, port), byte)
      }
    }
    debug.L1('done writing mcp pins config')
  } // end writePinsCfg

  async readPort(port, opts = {}) {
    if ('AB'.indexOf(port) === -1) {
      opts = port ? port : {}
      port = 'A'
    }
    let cmd = opts.cmd ? opts.cmd : 'gpio'
    let result = await this.read(portReg(registers.pin_cmd[cmd], port))
    debug.L2('read prev  ', this.ports[port].state.toFmtPrev('ARY'))
    debug.L2('read result', _.byteFormat(result, { in: 'DEC', out: 'ARY' }))
    debug.L2('read state ', this.ports[port].state.toFmt('ARY'))
    // if port pins changed without a write then update state
    if (_.bitChanges(_.byteFormat(result, { in: 'DEC', out: 'ARY' }), this.ports[port].state.toFmt('ARY'))) {
      this.ports[port].state.value = result
    }
    return opts.format ? this.ports[port].state.toFmt(opts.format) : result
  }

  async readPin(pin, port, opts = {}) {
    if ('AB'.indexOf(port) === -1) {
      opts = port ? port : {}
      port = 'A'
    }
    await this.readPort(port, opts)
    // TODO return just true or false not the decimal of pin - will need new version on npm
    return this.ports[port].state.bwOp(Math.pow(2, pin - 1), 'check') ? true : false
  }

  async writePort(byte, op, port = 'A') {
    // byte MUST be a decimal
    debug.L2(`port:${port}, op:${op}, current pins state\n ${this.ports[port].state.toFmt('PLC') }`)
    debug.L2(`byte passed \n [${ _.byteFormat(byte, { in: 'DEC', out: 'PLC'})}]:${byte}`)
    if (op !== 'force') {
      byte = this.ports[port].state.bwOp(byte, op)
    }
    debug.L2(`byte to write\n [${ _.byteFormat(byte, { in: 'DEC', out: 'PLC' })}]:${byte}\n=======`)
    await this.write(portReg(registers.pin_cmd.gpio, port), byte)
    //update to the saved state
    this.ports[port].state.value = byte
  }

  async pinsOn(pins, port, format) {
    if ('AB'.indexOf(port) === -1) {
      format = port
      port = 'A'
    }
    if (format) { pins = _.byteFormat(pins, { in: format, out: 'DEC' }) }
    await this.writePort(pins, 'on', port)
  }

  async allOn(port = 'A') {
    let pins = 255
    await this.writePort(pins, 'force', port)
  }

  async pinsOff(pins, port, format) {
    if ('AB'.indexOf(port) === -1) {
      format = port
      port = 'A'
    }
    if (format) { pins = _.byteFormat(pins, { in: format, out: 'DEC' }) }
    await this.writePort(pins, 'off', port)
  }

  async allOff(port = 'A') {
    let pins = 0
    await this.writePort(pins, 'force', port)
  }

  async toggle(pins, port, format) {
    if ('AB'.indexOf(port) === -1) {
      format = port
      port = 'A'
    }
    if (format) { pins = _.byteFormat(pins, { in: format, out: 'DEC' }) }
    await this.writePort(pins, 'toggle', port)
  }

  async allToggle(port = 'A') {
    let pins = 255
    await this.writePort(pins, 'toggle', port)
  }

  async force(pins, port, format) {
    if ('AB'.indexOf(port) === -1) {
      format = port
      port = 'A'
    }
    if (format) { pins = _.byteFormat(pins, { in: format, out: 'DEC' }) }
    await this.writePort(pins, 'force', port)
  }

} // end 23008

class MCP23017 extends MCP23008 {
  constructor(busObj, i2cAddress, opts = {}) {
    super(busObj, i2cAddress, opts)
    // add a second port
    opts.portID = 'B'
    opts.pids = opts.pidsB
    this.ports.B = new Port(opts)
    this.ports.B.state = new _.Byte(opts.stateB)
    this.ports.B.interrupt = opts.interruptB ? opts.interruptB : opts.interrupt
  }

  pin(id, port) {
    if (!port) {
      return this.ports.A.pin(id) ? this.ports.A.pin(id) : this.ports.B.pin(id)
    }
    return this.ports[port].pin(id)
  }

  pid(num, port) {
    console.log('pin for pid',this.ports[port].pins[num - 1])
    return this.ports[port].pins[num - 1].id
  }

} // end MCP23017 Class

// EXPORTS
module.exports = {
  MCP23008,
  MCP23017,
  pinConfigs
}

// Local Functions and Settings=============================

function portReg(reg, port) {
  // TODO check chip configuartion to know what to add for port B.  CUrrenly assume IOCON=1
  // index 0,1 ==== 'A','B'
  if ((port === 'B') || (port === 1)) { return reg += 0x10 } else { return reg }
}

/* ww1.microchip.com/downloads/en/DeviceDoc/21952b.pdf
 * or see MCP23017.pdf and MCP 23008.pdf in /docs
 * see table 1.5 and details in sections 1.6.x following
 * !!! for 23017 MUST initialize with bit 7 "BANK" of IOCON = 1 for the addresses below
 * then for all registers add 16 (0x10) to each reg address to talk to PortB pins
 * this will make reg addresses be equilvant for 23008 and PortA of 23017
 * reg addresses in the config objects are all in Hexidecminal
 */
// Chip Configuration to be used with Register  See Page 18 of 23017 doc
let chip_config = {
  // byte: ['NULL','INTPOL','ODR','HAEN','DISSLW','SEQOP','MIRROR','BANK']  // see page 18 of 23017 datasheet for 8 setting details
  cmd: 0x0A, // IOCON.BANK=0 (msb) at powerup so need to use 0x0A, if set to 1 then use
  default: {
    val: '10100010', // Split Banks port A + 0x10 = Port B,(ignored by 23008), Sequential operation disabled, active high=pulldown
    fmt: 'STR'
  },
  oneint: {
    val: '11100100', // same as default execpt int pins connected
    fmt: 'STR'
  }
}

let registers = {
  pin_config: {
    dir: 0,
    ivrt: 1,
    pullup: 6,
    intr: 2,
    usedef: 4,
    defval: 3,
  },
  pin_cmd: {
    intf: 7, // readonly
    intcap: 8, // readonly
    gpio: 9, // read/write
    olat: 10 // read only
  }
}