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jeffutter/history.ex

Last active November 16, 2016 05:17
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history.ex
defmodule Thermostat.TempSensor.History do
require Logger
use GenServer
use Timex
alias Thermostat.TempSensor.Entry, as: Entry
defstruct [:onewire_port, :onewire_id, :duration, :data, :dirty]
@history_duration 60 * 60 * 24
@pause_ms 60000
def start_link(onewire_port, onewire_id) do
GenServer.start_link(__MODULE__, [onewire_port, onewire_id], name: via_tuple(onewire_port, onewire_id))
end
def via_tuple(onewire_port, onewire_id) do
{:via, :gproc, {:n, :l, {:temp_sensor_history, onewire_port, onewire_id}}}
end
def init([onewire_port, onewire_id]) do
history = case read_history(onewire_port, onewire_id) do
{:ok, history} -> history
_ -> default(onewire_port, onewire_id)
end
Process.send_after(self, :update, @pause_ms)
{:ok, history}
end
defp default(onewire_port, onewire_id) do
%__MODULE__{onewire_port: onewire_port, onewire_id: onewire_id, duration: @history_duration, data: [], dirty: false}
end
def add(onewire_port, onewire_id, entry) do
via_tuple(onewire_port, onewire_id)
|> GenServer.cast({:add, entry})
end
def get_state(onewire_port, onewire_id) do
via_tuple(onewire_port, onewire_id)
|> GenServer.call(:get_state)
end
def handle_info(:update, state) do
if state.dirty do
state
|> write_history(state.onewire_port, state.onewire_id)
end
Process.send_after(self, :update, @pause_ms)
{:noreply, %__MODULE__{state | dirty: false}}
end
def handle_call(:get_state, _f, state) do
{:reply, state, state}
end
def handle_cast({:add, entry}, state) do
data = state.data |> trim_duration(state.duration)
first = data |> Enum.at(0)
second = data |> Enum.at(1)
rest = Enum.slice(data, 2..(length(data)))
data = add(first, second, rest, entry)
dirty = state.dirty || state.data != data
{:noreply, %__MODULE__{state | data: data, dirty: dirty}}
end
defp add(nil, nil, [], entry) do
[entry]
end
defp add(%Entry{temp: first_temp} = first, second, rest, %Entry{temp: entry_temp} = entry) when entry_temp != first_temp do
[entry, first, second]
|> compact
|> append(rest)
end
defp add(%Entry{temp: first_temp} = first, nil, rest, %Entry{temp: entry_temp} = entry) when entry_temp == first_temp do
[entry, first]
|> compact
|> append(rest)
end
defp add(%Entry{temp: first_temp}, %Entry{temp: second_temp} = second, rest, %Entry{temp: entry_temp} = entry) when entry_temp == first_temp and first_temp == second_temp do
[entry, second]
|> compact
|> append(rest)
end
defp add(%Entry{temp: first_temp} = first, %Entry{temp: second_temp} = second, rest, %Entry{temp: entry_temp} = entry) when entry_temp == first_temp and first_temp != second_temp do
[entry, first, second]
|> compact
|> append(rest)
end
defp add(_first, _second, _rest, _entry) do
[]
end
defp compact(list) do
list
|> Enum.filter(fn (x) -> x end)
end
defp append(h,t) do
h ++ t
end
defp trim_duration(data, duration, reversed \\ false)
defp trim_duration(data, duration, false) do
data
|> Enum.reverse
|> trim_duration(duration, true)
|> Enum.reverse
end
defp trim_duration(data, duration, true) do
case List.first(data) do
%Entry{time: time} ->
if Timex.shift(Timex.now, seconds: -duration) > Timex.parse!(time, "{ISO:Extended}") do
data
|> List.delete_at(0)
|> trim_duration(duration, true)
else
data
end
nil -> data
_ -> data
end
end
def latest(history) do
[head|_tail] = history.data
head
end
def to_list(history) do
data = history.data
|> pmap(&Entry.to_map/1)
data
end
defp pmap(collection, function) do
collection
|> Enum.map(&Task.async(fn -> function.(&1) end))
|> Enum.map(&Task.await(&1))
end
defp history_location(onewire_port, onewire_id) do
File.mkdir_p!("/root/history/#{onewire_port}")
"/root/history/#{onewire_port}/#{onewire_id}"
end
defp read_history(onewire_port, onewire_id) do
hl = history_location(onewire_port, onewire_id)
case File.read(hl) do
{:ok, serialized} ->
case unserialize(serialized) do
{:ok, history} -> {:ok, history}
{:error, _} ->
Logger.error "Error Parsing #{hl}"
{:error, "Parse Error"}
end
{:error, _} ->
Logger.error "Error Loading #{hl}"
{:error, "Load Error"}
end
end
def write_history(history, onewire_port, onewire_id) do
hl = history_location(onewire_port, onewire_id)
case serialize(history) do
{:ok, serialized} ->
case File.write(hl, serialized, [:sync]) do
{:error, _} ->
Logger.error "Error Writing #{hl}"
history
:ok ->
history
end
{:error, _} ->
Logger.error "Error Serializing History"
history
end
end
def serialize(history) do
{:ok, :erlang.term_to_binary(history)}
end
def unserialize(string) do
{:ok, :erlang.binary_to_term(string)}
end
end
defimpl Msgpax.Packer, for: Thermostat.TempSensor.History do
def pack(history) do
history
|> Thermostat.TempSensor.History.to_list
|> @protocol.List.pack
end
end
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