local GPIO=require"GPIO"

GPIO.setmode(GPIO.BOARD)

--[[
table.foreach(GPIO,function(k,v)
  if type(v)=="string" or type(v)=="number" then print(k,v) end
end
)
--]]

i2c={sda=3,scl=5}
--GPIO.setup(i2c.sda,GPIO.I2C)
--GPIO.setup(i2c.scl,GPIO.I2C)

uart={tx=8,rx=10}
--GPIO.setup(uart.tx,GPIO.SERIAL)
--GPIO.setup(uart.rx,GPIO.SERIAL)

spi={mosi=19,miso=21,sclk=23}
--GIO.setup(spi.mosi, GPIO.SPI)
--GIO.setup(spi.miso, GPIO.SPI)
--GIO.setup(spi.sclk, GPIO.SPI)

--[[
pins={11,12,13,15,16,18,22,24,26}
for _,p in ipairs(pins) do 
  GPIO.setup(p,GPIO.IN)
end
for _,p in ipairs(pins) do 
  print(p, GPIO.input(p))
end
--]]

local b = false
--GPIO.setup(26,GPIO.IN,GPIO.PUD_UP)
GPIO.setup(26,GPIO.IN)
while(true) do
  --GPIO.wait_for_edge(26, GPIO.BOTH)
  local b0 = GPIO.input(26)
  if b0 ~= b then
    print(b0)
  end
  b = b0
end

local pinfuncs={}
pinfuncs[GPIO.IN] = "in"
pinfuncs[GPIO.OUT] = "out"
pinfuncs[GPIO.SPI] = "spi"
pinfuncs[GPIO.I2C] = "i2c"
pinfuncs[GPIO.PWM] = "pwm"
pinfuncs[GPIO.SERIAL] = "ser"
pinfuncs[GPIO.UNKNOWN] = "unk"
setmetatable(pinfuncs,{__index=function(k) return tostring(k) end})

pins={3,5,7,8,10}

for i=1,#pins do
 print(i, pins[i], pinfuncs[GPIO.gpio_function(pins[i])])
end

GPIO.cleanup()

local P = require "posix"

-- write str to the named file
function putfile(name,str)
  local f = assert(io.open(name,"w"))
  f:write(str)
  f:close()
end

-- read the named file and return its content
function getfile(name)
  local f = assert(io.open(name,"r"))
  local str f:read"*a"
  f:close()
  return str
end

-- transform a list into a set for quick lookup
function SET(t)
  local s = {}
  for _,v in ipairs(t) do
    s[v] = true
  end
  return s
end


-- container for GPIO functions
gpio={
  pins1_1 = SET{ -- Original RPi A, B
     0,  1,          4,          7,
     8,  9, 10, 11,         14, 15,
        17, 18,         21, 22, 23,
    24, 25,       },

  pins1_2 = SET{ -- Rev 2 A, B
             2,  3,  4,          7,
     8,  9, 10, 11,         14, 15,
        17, 18,             22, 23,
    24, 25,     27},

  pins2_0 = SET{ -- A+, B+, 2A, 2B
             2,  3,  4,  5,  6,  7,
     8,  9, 10, 11, 12, 13, 14, 15,
    16, 17, 18, 19, 20, 21, 22, 23,
    24, 25, 26, 27},
}

-- default to RPi B+ board
-- TODO: Read /proc/cpuinfo and get this right
gpio.pins = gpio.pins2_0

-- export a sysfs pin to userland
function gpio.export(pin)
  assert(gpio.pins[pin], "Can't use pin")
  putfile("/sys/class/gpio/export",tostring(pin))
end

-- return a sysfs pin to the kernel
function gpio.unexport(pin)
  assert(gpio.pins[pin], "Can't use pin")
  putfile("/sys/class/gpio/unexport",tostring(pin))
end

-- userland path to a specific pin's atribute file
function gpio.pinpath(pin,attr)
  return ("/sys/class/gpio/gpio%d/%s"):format(pin,attr)
end

-- set pin direction
function gpio.direction(pin,dir)
  local path = gpio.pinpath(pin, "direction")
print("Setting "..path.." to "..dir)
  putfile(path, dir)
end

-- set pin edge detector
function gpio.edge(pin,edge)
  local path = gpio.pinpath(pin, "edge")
print("Setting "..path.." to "..edge)
  putfile(path, edge)
end

-- blocking wait with timeout for an edge on a pin
function gpio.wait(pin)
  assert(gpio.pins[pin], "Can't use pin")
  local path = gpio.pinpath(pin, "value")
  if not gpio.pinfd then 
    gpio.pinfd = P.open(path, P.O_RDONLY)
  end
  local p = gpio.pinfd
  if not gpio.fds then gpio.fds = {} end
  if not gpio.fds[p] then gpio.fds[p] = {events={}, revents={}} end
  gpio.fds[p].events.PRI=true
  local ret = P.poll(gpio.fds, 10000)
  if ret == 0 then return 0 end
  P.lseek(p,0,P.SEEK_SET)
  ret = tonumber(P.read(p,8))
  --P.close(p)
  --gpio.pinfd = nil
  return ret
end 


-- Use pin P1-28 aka GPIO7 for SPLear alerts
gpio.export(7)
gpio.direction(7,"in")
gpio.edge(7,"rising")

while(true) do
  local r = gpio.wait(7)
  if r == 0 then
    --print"timeout"
  elseif r==1 then
    local tim = P.gettimeofday()
    print("eek "..tim.sec..'.'..tim.usec)
  else
    print("???", r)
  end
end

if gpio.pinfd then P.close(gpio.pinfd) end