--- **Utilities**  DCS Simple Text-To-Speech (STTS).
--
--
-- @module Utilities.STTS
-- @image MOOSE.JPG

--- [DCS Enum world](https://wiki.hoggitworld.com/view/DCS_enum_world)
-- @type STTS
-- @field #string DIRECTORY Path of the SRS directory.

--- Simple Text-To-Speech
--
-- Version 0.4 - Compatible with SRS version 1.9.6.0+
--
-- # DCS Modification Required
--
-- You will need to edit MissionScripting.lua in DCS World/Scripts/MissionScripting.lua and remove the sanitization.
-- To do this remove all the code below the comment - the line starts "local function sanitizeModule(name)"
-- Do this without DCS running to allow mission scripts to use os functions.
--
-- *You WILL HAVE TO REAPPLY AFTER EVERY DCS UPDATE*
--
-- # USAGE:
--
-- Add this script into the mission as a DO SCRIPT or DO SCRIPT FROM FILE to initialize it
-- Make sure to edit the STTS.SRS_PORT and STTS.DIRECTORY to the correct values before adding to the mission.
-- Then its as simple as calling the correct function in LUA as a DO SCRIPT or in your own scripts.
--
-- Example calls:
--
--     STTS.TextToSpeech("Hello DCS WORLD","251","AM","1.0","SRS",2)
--
-- Arguments in order are:
--
--  * Message to say, make sure not to use a newline (\n) !
--  * Frequency in MHz
--  * Modulation - AM/FM
--  * Volume - 1.0 max, 0.5 half
--  * Name of the transmitter - ATC, RockFM etc
--  * Coalition - 0 spectator, 1 red 2 blue
--  * OPTIONAL - Vec3 Point i.e Unit.getByName("A UNIT"):getPoint() - needs Vec3 for Height! OR null if not needed
--  * OPTIONAL - Speed -10 to +10
--  * OPTIONAL - Gender male, female or neuter
--  * OPTIONAL - Culture - en-US, en-GB etc
--  * OPTIONAL - Voice - a specific voice by name. Run DCS-SR-ExternalAudio.exe with --help to get the ones you can use on the command line
--  * OPTIONAL - Google TTS - Switch to Google Text To Speech - Requires STTS.GOOGLE_CREDENTIALS path and Google project setup correctly
--
--
-- ## Example
--
-- This example will say the words "Hello DCS WORLD" on 251 MHz AM at maximum volume with a client called SRS and to the Blue coalition only
--
--     STTS.TextToSpeech("Hello DCS WORLD","251","AM","1.0","SRS",2,null,-5,"male","en-GB")
--
-- ## Example
--
-- This example will say the words "Hello DCS WORLD" on 251 MHz AM at maximum volume with a client called SRS and to the Blue coalition only centered on the position of the Unit called "A UNIT"
--
--     STTS.TextToSpeech("Hello DCS WORLD","251","AM","1.0","SRS",2,Unit.getByName("A UNIT"):getPoint(),-5,"male","en-GB")
--
-- Arguments in order are:
--
--  * FULL path to the MP3 OR OGG to play
--  * Frequency in MHz - to use multiple separate with a comma - Number of frequencies MUST match number of Modulations
--  * Modulation - AM/FM - to use multiple
--  * Volume - 1.0 max, 0.5 half
--  * Name of the transmitter - ATC, RockFM etc
--  * Coalition - 0 spectator, 1 red 2 blue
--
-- ## Example
--
-- This will play that MP3 on 255MHz AM & 31 FM at half volume with a client called "Multiple" and to Spectators only
--
--     STTS.PlayMP3("C:\\Users\\Ciaran\\Downloads\\PR-Music.mp3","255,31","AM,FM","0.5","Multiple",0)
--
-- @field #STTS
STTS = {
  ClassName = "STTS",
  DIRECTORY = "",
  SRS_PORT = 5002,
  GOOGLE_CREDENTIALS = "C:\\Users\\Ciaran\\Downloads\\googletts.json",
  EXECUTABLE = "DCS-SR-ExternalAudio.exe"
}

--- FULL Path to the FOLDER containing DCS-SR-ExternalAudio.exe - EDIT TO CORRECT FOLDER
STTS.DIRECTORY = "D:/DCS/_SRS"

--- LOCAL SRS PORT - DEFAULT IS 5002
STTS.SRS_PORT = 5002

--- Google credentials file
STTS.GOOGLE_CREDENTIALS = "C:\\Users\\Ciaran\\Downloads\\googletts.json"

--- DON'T CHANGE THIS UNLESS YOU KNOW WHAT YOU'RE DOING
STTS.EXECUTABLE = "DCS-SR-ExternalAudio.exe"

--- Function for UUID.
function STTS.uuid()
  local random = math.random
  local template = 'yxxx-xxxxxxxxxxxx'
  return string.gsub( template, '[xy]', function( c )
    local v = (c == 'x') and random( 0, 0xf ) or random( 8, 0xb )
    return string.format( '%x', v )
  end )
end

--- Round a number.
-- @param #number x Number.
-- @param #number n Precision.
function STTS.round( x, n )
  n = math.pow( 10, n or 0 )
  x = x * n
  if x >= 0 then
    x = math.floor( x + 0.5 )
  else
    x = math.ceil( x - 0.5 )
  end
  return x / n
end

--- Function returns estimated speech time in seconds.
-- Assumptions for time calc: 100 Words per min, average of 5 letters for english word so
--
--   * 5 chars * 100wpm = 500 characters per min = 8.3 chars per second
--
-- So length of msg / 8.3 = number of seconds needed to read it. rounded down to 8 chars per sec map function:
--
-- * (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
-- 
-- @param #number length can also be passed as #string
-- @param #number speed Defaults to 1.0
-- @param #boolean isGoogle We're using Google TTS
function STTS.getSpeechTime(length,speed,isGoogle)

  local maxRateRatio = 3

  speed = speed or 1.0
  isGoogle = isGoogle or false

  local speedFactor = 1.0
  if isGoogle then
    speedFactor = speed
  else
    if speed ~= 0 then
      speedFactor = math.abs( speed ) * (maxRateRatio - 1) / 10 + 1
    end
    if speed < 0 then
      speedFactor = 1 / speedFactor
    end
  end

  local wpm = math.ceil( 100 * speedFactor )
  local cps = math.floor( (wpm * 5) / 60 )

  if type( length ) == "string" then
    length = string.len( length )
  end

  return length/cps --math.ceil(length/cps)
end

--- Text to speech function.
function STTS.TextToSpeech( message, freqs, modulations, volume, name, coalition, point, speed, gender, culture, voice, googleTTS )
  if os == nil or io == nil then
    env.info( "[DCS-STTS] LUA modules os or io are sanitized. skipping. " )
    return
  end

  speed = speed or 1
  gender = gender or "female"
  culture = culture or ""
  voice = voice or ""
  coalition = coalition or "0"
  name = name or "ROBOT"
  volume = 1
  speed = 1

  message = message:gsub( "\"", "\\\"" )

  local cmd = string.format( "start /min \"\" /d \"%s\" /b \"%s\" -f %s -m %s -c %s -p %s -n \"%s\" -h", STTS.DIRECTORY, STTS.EXECUTABLE, freqs or "305", modulations or "AM", coalition, STTS.SRS_PORT, name )

  if voice ~= "" then
    cmd = cmd .. string.format( " -V \"%s\"", voice )
  else

    if culture ~= "" then
      cmd = cmd .. string.format( " -l %s", culture )
    end

    if gender ~= "" then
      cmd = cmd .. string.format( " -g %s", gender )
    end
  end

  if googleTTS == true then
    cmd = cmd .. string.format( " -G \"%s\"", STTS.GOOGLE_CREDENTIALS )
  end

  if speed ~= 1 then
    cmd = cmd .. string.format( " -s %s", speed )
  end

  if volume ~= 1.0 then
    cmd = cmd .. string.format( " -v %s", volume )
  end

  if point and type( point ) == "table" and point.x then
    local lat, lon, alt = coord.LOtoLL( point )

    lat = STTS.round( lat, 4 )
    lon = STTS.round( lon, 4 )
    alt = math.floor( alt )

    cmd = cmd .. string.format( " -L %s -O %s -A %s", lat, lon, alt )
  end

  cmd = cmd .. string.format( " -t \"%s\"", message )

  if string.len( cmd ) > 255 then
    local filename = os.getenv( 'TMP' ) .. "\\DCS_STTS-" .. STTS.uuid() .. ".bat"
    local script = io.open( filename, "w+" )
    script:write( cmd .. " && exit" )
    script:close()
    cmd = string.format( "\"%s\"", filename )
    timer.scheduleFunction( os.remove, filename, timer.getTime() + 1 )
  end

  if string.len( cmd ) > 255 then
    env.info( "[DCS-STTS] - cmd string too long" )
    env.info( "[DCS-STTS] TextToSpeech Command :\n" .. cmd .. "\n" )
  end
  os.execute( cmd )

  return STTS.getSpeechTime( message, speed, googleTTS )
end

--- Play mp3 function.
-- @param #string pathToMP3 Path to the sound file.
-- @param #string freqs Frequencies, e.g. "305, 256".
-- @param #string modulations Modulations, e.g. "AM, FM".
-- @param #string volume Volume, e.g. "0.5".
function STTS.PlayMP3( pathToMP3, freqs, modulations, volume, name, coalition, point )

  local cmd = string.format( "start \"\" /d \"%s\" /b /min \"%s\" -i \"%s\" -f %s -m %s -c %s -p %s -n \"%s\" -v %s -h", STTS.DIRECTORY, STTS.EXECUTABLE, pathToMP3, freqs or "305", modulations or "AM", coalition or "0", STTS.SRS_PORT, name or "ROBOT", volume or "1" )

  if point and type( point ) == "table" and point.x then
    local lat, lon, alt = coord.LOtoLL( point )

    lat = STTS.round( lat, 4 )
    lon = STTS.round( lon, 4 )
    alt = math.floor( alt )

    cmd = cmd .. string.format( " -L %s -O %s -A %s", lat, lon, alt )
  end

  env.info( "[DCS-STTS] MP3/OGG Command :\n" .. cmd .. "\n" )
  os.execute( cmd )

end