## Commands core

Core Module - Commands - Factorio command making module that makes commands with better parse and more modularity

### Usage

    --- Full code example, see below for explaination
    Commands.new_command('repeat-name', 'Will repeat you name a number of times in chat.')
    :add_param('repeat-count', false, 'number-range-int', 1, 5) -- required int in range 1 to 5 inclusive
    :add_param('smiley', true, function(input, player, reject) -- optional boolean default false
        if not input then return end
        if input:lower() == 'true' or input:lower() == 'yes' then
            return true
        else
            return false
        end
    end)
    :set_defaults{ smiley=false }
    :set_flag('admin_only', true) -- command is admin only
    :add_alias('name', 'rname') -- allow alias: name and rname
    :register(function(player, repeat_count, smiley, raw)
        game.print(player.name..' used a command with input: '..raw)

        local msg = ') '..player.name
        if smiley then
            msg = ':'..msg
        end

        for 1 = 1,repeat_count do
            Command.print(1..msg)
        end
    end)

    --- Example Command:
    -- How for the fun part making the commands, the commands can be set up with any number of params and flags that you want,
    -- you can add aliases for the commands and set default values for optional params and of course register your command callback
    -- in our example we will just have a command that will repeat the users name in chat X amount of times and only allow admins to use it.

    -- First we create the new command, nb this will not register the command to the game this is done at the end, we will call
    -- the command "repeat-name" and set the help message as follows:
    Commands.new_command('repeat-name', 'Will repeat you name a number of times in chat.')

    -- Now for our first param we will call "repeat-count" and it will be a required value between 1 and 5 inclusive:
    :add_param('repeat-count', false, 'number-range-int', 1, 5)

    -- Our second param we need a custom parse for but we have not defined it, this is an option for when it is unlikely for
    -- any other command to use the same input type; however in our case it will just be a boolean which should be noted as being
    -- included in the general command parse config. As for the param its self it will be called "smiley" and will be optional with
    -- a default value of false:
    :add_param('smiley', true, function(input, player, reject)
        -- since it is optional the input can be nil, in which case we just return
        if not input then return end
        -- if it is not nil then we check for a truthy value
        if input:lower() == 'true' or input:lower() == 'yes' then
            return true
        else
            -- note that because we did not return nil or reject then false will be passed to command callback, see example parse
            return false
        end
    end)

    -- Once all params are defined you can now define some default values if you have optional params, the default value will be used only
    -- when no value is given as input, if an invalid value is given then the command will still fail and this value will not be used, the
    -- default can also be a function which is passed the player using the command and returns a value. Here we set the default for "smiley" to false:
    :set_defaults{smiley=false}

    -- Another example of defaults if we have: item, amount[opt], player[opt]
    :set_defaults{
        amount = 50, -- more than one value can be set at a time
        player = function(player)
            return player -- default is the player using the command
        end
    }

    -- Now the params are set up we can alter how the command works, we can set auth flags, add aliases to this command or enable "auto concat"
    -- which is when you want all extra words to be concatenated onto the end of the last param, useful for reason or messages:
    :set_flag('admin_only', true) -- in our case we want "admin_only" to be set to true so only admins can use the command
    :add_alias('name', 'rname') -- we also add two aliases here: "name" and "rname" which point to this command
    -- :enable_auto_concat() we do not use this in our case but this can also be used to enable the "auto concat" feature

    -- And finally we want to register a callback to this command, the callback is what defines what the command does, can be as complex as you
    -- want it to be to as simple as our example; the command receives two params plus all that you have defines:
    -- 1) the player who used the command
    -- 2) in our case repeat_count which will be a number
    -- 3) in our case smiley which will be a boolean
    -- 4) the raw input; this param is always last as is always present as a catch all
    :register(function(player, repeat_count, smiley, raw)
        -- this is to show the value for raw as this is an example command, the log file will also show this
        game.print(player.name..' used a command with input: '..raw)
        local msg = ') '..player.name
        if smiley then
            -- this is where that smiley param is used
            msg = ':'..msg
        end
        for 1 = 1,repeat_count do
            -- this print function will return ANY value to the user in a desync safe manor, this includes if the command was used through rcon
            Command.print(1..msg)
        end
        -- see below for what else can be used here
    end)

    -- Other values that can be returned from register
    Commands.print(any,colour[opt]) -- this will return any value value to the user including if it is ran through rcon console
    Commands.error(message[opt]) -- this returns a warning to the user, aka an error that does not prevent execution of the command
    return Commands.error(message[opt]) -- this returns an error to the user, and will halt the command execution, ie no success message is returned
    Commands.success(message[opt]) -- used to return a success message however don't use this method see below
    return Commands.success(message[opt]) -- will return the success message to the user and your given message, halts execution
    return <any> -- if any value is returned then it will be returned to the player via a Commands.success call

    --- Example Authenticator:
    -- The command system is best used when you can control who uses commands;
    -- to do this would would need to define an authenticator which is ran every time a command is run;
    -- in this example I will show a simple one that requires certain commands to require the user to be a game admin.

    -- For our admin only example we will set a flag to true when we want it to be admin only;
    -- when we define the command will will use :set_flag('admin_only', true);
    -- then inside the authenticator we will test if the flag is present using: if flags.admin_only then

    -- When the authenticator is called by the command handler it will be passed 4 arguments:
    -- 1) player - the player who used the command
    -- 2) command - the name of the command that is being used
    -- 3) flags - the flags which have been set for this command, flags are set with :set_flag(name, value)
    -- 4) reject - the reject function which is the preferred method to prevent execution of the command

    -- No return is required to allow the command to execute but it is best practice to return true;
    -- we do this in two cases in our authenticator:
    -- 1) when the "admin_only" flag is not set, which we take assume that any one can use it
    -- 2) when the "admin_only" flag is set, and the player is admin

    -- When want to prevent exicution of the command we must reject it, listed is how that can be done:
    -- 1) return false -- this is the most basic rejection and should only be used while testing
    -- 2) return reject -- returning the reject function is as a fail safe in case you forget to call it, same as returning false
    -- 3) reject() -- this will block execution without to allowing further code to be ran in your authenticator
    -- 4) reject('This command is for admins only!') -- Using reject as a function allows a error message to be returned
    -- 5) return reject() -- using return on either case above is best practice as you should execute all your code before rejecting

    -- Example Code:
    Commands.add_authenticator(function(player, command, flags, reject)
        -- Check if the command is admin only
        if flags.admin_only then
            -- Return true if player is admin, or reject and return error message
            return player.admin or reject('This command is for admins only!')
        else
            -- Return true if command was not admin only
            return true
        end
    end)

    --- Example Parse:
    -- Before you make a command it is important to understand the most powerful feature of this command handler;
    -- when you define a command you are able to type the params and have then be parsed and validated before your command is executed;
    -- This module should is paired with a general command parse but you may want to create your own.

    -- For our example we will create a parse to accept only integer numbers in a given range:
    -- 1) we will give it the name "number-range-int" this is the "type" that the input is expected to be
    -- 2) when we define the type we will also define the min and max of the range so we can use the function more than once
    :add_param('repeat_count', false, 'number-range-int', 5, 10) -- "repeat_count" is required "number-range-int" in a range 5 to 10 inclusive

    -- The command parse will be passed 3 arguments plus any other which you define, in our case:
    -- 1) input - the input that has been given by the user for this param, the role of this function is to transform this value
    -- nb: the input is a string but can be nil if the param is marked as optional
    -- 2) player - the player who is using the command, this is always present
    -- 3) reject - the reject function to throw an error to the user, this is always present
    -- 4) range_min - the range min, this is user defined and has the value given when the param is defined
    -- 5) range_max - the range max, this is user defined and has the value given when the param is defined

    -- When returning from the param parse you have a few options with how to do this:
    -- 1) you return the new value for the param (any non nil value) this value is then passed to the command callback
    -- 2) not returning will cause a generic invalid error and the command is rejected, not recommenced
    -- 3) return reject -- this is just a failsafe in case the function is not called, same as no return
    -- 4) return reject() -- will give a shorter error message as you pass a nil custom error
    -- 5) return reject('Number entered is not in range: '..range_min..', '..range_max) -- returns a custom error to the user
    -- nb: if you do not return reject after you call it then you will still be returning nil so there will be a duplicate error message

    -- It should be noted that if you want to expand on an existing parse you can use Commands.parse(type, input, player, reject)
    -- this function will either return a new value for the input or nil, if it is nil you should return nil to prevent duplicate
    -- error messages to the user:
    input = Commands.parse('number-int', input, player, reject)
    if not input then return end -- nil check

    -- Example Code:
    Commands.add_parse('number-range-int',function(input, player, reject, range_min, range_max)
        local rtn = tonumber(input) and math.floor(tonumber(input)) or nil -- converts input to number
        if not rtn or rtn < range_min or rtn > range_max then
            -- the input is either not a number or is outside the range
            return reject('Number entered is not in range: '..range_min..', '..range_max)
        else
            -- returns the input as a number value rather than a string, thus the param is now the correct type
            return rtn
        end
    end)

### Dependencies

utils.game
expcore.common

### Tables

defines | Values returned by the signal functions to cause the command system to react
commands | Custom command data will be stored here
authorization | Custom function are stored here which control who can use what commands
parse_functions | Used to store default functions which are common parse function such as player or number in range
_prototype | Used to store functions which gets added to new custom commands

### Fields

authorization_fail_on_error | Set true to have authorize fail if a callback fails to run, more secure

### Authenication

add_authenticator(callback) | Adds an authorization callback, function used to check if a player if allowed to use a command
remove_authenticator(callback) | Removes an authorization callback
authorize(player, command_name) | Mostly used internally, calls all authorization callbacks, returns if the player is authorized

### Getters

get([player]) | Gets all commands that a player is allowed to use, game commands are not included
search(keyword[, player]) | Searches command names and help messages to find possible commands, game commands are included

### Parse

add_parse(name, callback) | Adds a parse function which can be called by name (used in add_param) nb: this is not required as you can use the callback directly this just allows it to be called by name
remove_parse(name) | Removes a parse function, see add_parse for adding them
parse(name, input, player, reject) | Intended to be used within other parse functions, runs a parse and returns success and new value

### Creation

new_command(name, help) | Creates a new command object to added details to, note this does not register the command to the game api
Commands._prototype:add_param(name[, optional=false][, parse=pass function through][, ...]) | Adds a new param to the command this will be displayed in the help and used to parse the input
Commands._prototype:set_defaults(defaults) | Add default values to params, only as an effect if the param is optional, if default value is a function it is called with acting player
Commands._prototype:set_flag(name[, value=true]) | Adds a tag to the command which is passed via the flags param to the authenticators, can be used to assign command roles or type
Commands._prototype:add_alias(any) | Adds an alias, or multiple, that will also be registered with the same callback, eg /teleport can be used as /tp
Commands._prototype:enable_auto_concat() | Enables auto concatenation of any params on the end so quotes are not needed for last param nb: this will disable max param checking as they will be concatenated onto the end of that last param this can be useful for reasons or longs text, can only have one per command
Commands._prototype:register(callback) | Adds the callback to the command and registers all aliases, params and help message with the game api nb: this must be the last function ran on the command and must be done for the command to work

### Status

error([error_message=''][, play_sound=utility/wire_pickup]) | Sends an error message to the player and when returned will stop exicution of the command nb: this is for non fatal errors meaning there is no log of this event, use during register callback
internal_error(success, command_name, error_message) | Sends an error to the player and logs the error, used with pcall within command handler please avoid direct use nb: use error(error_message) within your callback to trigger do not trigger directly as code exictuion may still continue
success([value]) | Sends a value to the player, followed by a command complete message nb: returning any value from your callback will trigger this function, return this function to prevent duplicate messages
print(value, colour) | Sends a value to the player, different to success as this does not signal the end of your command
run_command(command_event) | Main event function that is ran for all commands, used internally please avoid direct use

### Dependencies

# utils.game
# expcore.common

### Tables

# defines

  Values returned by the signal functions to cause the command system to react

  Fields:
  - error
  - unauthorized
  - success
# commands

  Custom command data will be stored here

# authorization

  Custom function are stored here which control who can use what commands

# parse_functions

  Used to store default functions which are common parse function such as player or number in range

# _prototype

  Used to store functions which gets added to new custom commands

### Fields

# authorization_fail_on_error

  Set true to have authorize fail if a callback fails to run, more secure

### Authenication

# add_authenticator(callback)

  Adds an authorization callback, function used to check if a player if allowed to use a command

  Parameters:
  - callback : (function) the callback you want to register as an authenticator
  Returns:
  - (number) the index it was inserted at use to remove the callback, if anon function used
  Usage:

      -- Test if a command is admin only and if the player is admin
      local admin_authenticator =
      Commands.add_authenticator(function(player, command, flags, reject)
          if flags.admin_only then
              return player.admin or reject('This command is for admins only!')
          else
              return true
          end
      end)

# remove_authenticator(callback)

  Removes an authorization callback

  Parameters:
  - callback : (function or number) the callback to remove, an index returned by add_authenticator can be passed
  Returns:
  - (boolean) if the callback found and removed successfuly
  Usage:

      -- Removing the admin authenticator, can not be done dueing runtime
      Commands.remove_authenticator(admin_authenticator)

# authorize(player, command_name)

  Mostly used internally, calls all authorization callbacks, returns if the player is authorized

  Parameters:
  - player : (LuaPlayer) the player that is using the command, passed to callbacks
  - command_name : (string) the command that is being used, passed to callbacks
  Returns:
  - (boolean) true player is authorized
  - (string) commands const for success

  ##### Or

  - (boolean) false player is unauthorized
  - (string or locale_string) the reason given by the authenticator
  Usage:

      -- Test if a player can use "repeat-name"
      local authorized, status = Commands.authorize(game.player, 'repeat-name')

### Getters

# get([player])

  Gets all commands that a player is allowed to use, game commands are not included

  Parameters:
  - player : (LuaPlayer) the player that you want to get commands of, nil will return all commands (optional)
  Returns:
  - (table) all commands that that player is allowed to use, or all commands
  Usage:

      -- Get the command you are allowed to use
      local commands = Commands.get(game.player)

      -- Get all commands that are registered
      local commands = Commands.get()

# search(keyword[, player])

  Searches command names and help messages to find possible commands, game commands are included

  Parameters:
  - keyword : (string) the word which you are trying to find in your search
  - player : (LuaPlayer) the player to get allowed commands of, if nil all commands are searched (optional)
  Returns:
  - (table) all commands that contain the key word, and allowed by player if player given
  Usage:

      -- Get all commands which "repeat"
      local commands = Commands.search('repeat')

      -- Get all commands which "repeat" and you are allowed to use
      local commands = Commands.search('repeat', game.player)

### Parse

# add_parse(name, callback)

  Adds a parse function which can be called by name (used in add_param) nb: this is not required as you can use the callback directly this just allows it to be called by name

  Parameters:
  - name : (string) the name of the parse, should be the type like player or player_alive, must be unique
  - callback : (function) the callback that is ran to parse the input
  Returns:
  - (boolean) was the parse added will be false if the name is already used
  Usage:

      -- Adding a parse to validate ints in a given range
      Commands.add_parse('number-range-int', function(input, player, reject, range_min, range_max)
          local rtn = tonumber(input) and math.floor(tonumber(input)) or nil -- converts input to number
          if not rtn or rtn < range_min or rtn > range_max then
              -- the input is either not a number or is outside the range
              return reject('Number entered is not in range: '..range_min..', '..range_max)
          else
              -- returns the input as a number rather than a string, thus the param is now the correct type
              return rtn
          end
      end)

# remove_parse(name)

  Removes a parse function, see add_parse for adding them

  Parameters:
  - name : (string) the name of the parse to remove
  Usage:

      -- Removing a parse
      Commands.remove_parse('number-range-int')

# parse(name, input, player, reject)

  Intended to be used within other parse functions, runs a parse and returns success and new value

  Parameters:
  - name : (string) the name of the parse to call, must be registered parse
  - input : (string) string the input to pass to the parse, must be a string but not necessarily the original input
  - player : (LuaPlayer) the player that is using the command
  - reject : (function) the reject function that was passed by the command hander
  Returns:
  - (any) the new value for the input, may be nil, if nil then either there was an error or input was nil
  Usage:

      -- Parsing a int in a given range
      local parsed_input = Commands.parse('number-range-int', '7', player, reject, 1, 10) -- valid range 1 to 10

### Creation

# new_command(name, help)

  Creates a new command object to added details to, note this does not register the command to the game api

  Parameters:
  - name : (string) the name of the command to be created
  - help : (string) the help message for the command
  Returns:
  - (Commands._prototype) this will be used with other functions to generate the command functions
  Usage:

      -- Define a new command
      local command =
      Commands.new_command('repeat-name', 'Will repeat you name a number of times in chat.')

# Commands._prototype:add_param(name[, optional=false][, parse=pass function through][, ...])

  Adds a new param to the command this will be displayed in the help and used to parse the input

  Parameters:
  - name : (string) the name of the new param that is being added to the command
  - optional : (boolean) is this param required for this command, these must be after all required params (default: false)
  - parse : (string or function) this function will take the input and return a new (or same) value (default: pass function through)
  - ... : extra args you want to pass to the parse function; for example if the parse is general use (optional)
  Returns:
  - (Commands._prototype) pass through to allow more functions to be called
  Usage:

      -- Adding a param which has an parse defined
      command:add_param('repeat-count', false, 'number-range-int', 1, 5)

      -- Adding a param which has a custom parse, see Commands.add_parse for details
      command:add_param('smiley', true, function(input, player, reject)
          if not input then return end
          return input:lower() == 'true' or input:lower() == 'yes' or false
      end)

# Commands._prototype:set_defaults(defaults)

  Add default values to params, only as an effect if the param is optional, if default value is a function it is called with acting player

  Parameters:
  - defaults : (table) table which is keyed by the name of the param and the value is the default value
  Returns:
  - (Commands._prototype) pass through to allow more functions to be called
  Usage:

      -- Adding default values
      command:set_defaults{
          smiley = false,
          -- not in example just used to show arguments given
          player_name = function(player)
              return player.name
          end
      }

# Commands._prototype:set_flag(name[, value=true])

  Adds a tag to the command which is passed via the flags param to the authenticators, can be used to assign command roles or type

  Parameters:
  - name : (string) the name of the tag to be added, set to true if no value is given
  - value : (any) the tag that you want can be anything that the authenticators are expecting (default: true)
  Returns:
  - (Commands._prototype) pass through to allow more functions to be called
  Usage:

      -- Setting a custom flag
      command:set_flag('admin_only', true)

      -- When value is true it does not need to be given
      command:set_flag('admin_only')

# Commands._prototype:add_alias(any)

  Adds an alias, or multiple, that will also be registered with the same callback, eg /teleport can be used as /tp

  Parameters:
  - any : (string) ... amount of aliases that you want this command to be callable with
  Returns:
  - (Commands._prototype) pass through to allow more functions to be called
  Usage:

      -- Added multiple aliases to a command
      command:add_alias('name', 'rname')

# Commands._prototype:enable_auto_concat()

  Enables auto concatenation of any params on the end so quotes are not needed for last param nb: this will disable max param checking as they will be concatenated onto the end of that last param this can be useful for reasons or longs text, can only have one per command

  Returns:
  - (Commands._prototype) pass through to allow more functions to be called
  Usage:

      -- Enable auto concat for a command
      command:enable_auto_concat()

# Commands._prototype:register(callback)

  Adds the callback to the command and registers all aliases, params and help message with the game api nb: this must be the last function ran on the command and must be done for the command to work

  Parameters:
  - callback : (function) the callback for the command, will receive the player running command, and params added with add_param
  Usage:

      -- Registering your command to the game api
      command:register(function(player, repeat_count, smiley, _)
          local msg = ') '..player.name
          if smiley then msg = ':'..msg end

          for 1 = 1,repeat_count do
              Command.print(1..msg)
          end
      end)

### Status

# error([error_message=''][, play_sound=utility/wire_pickup])

  Sends an error message to the player and when returned will stop exicution of the command nb: this is for non fatal errors meaning there is no log of this event, use during register callback

  Parameters:
  - error_message : (string) an optional error message that can be sent to the user (default: '')
  - play_sound : (string) the sound to play for the error (default: utility/wire_pickup)
  Returns:
  - (Commands.defines.error) return this to command handler to exit execution
  Usage:

      -- Send an error message to the player, and stops further code running
      return Commands.error('The player you selected is offline')

# internal_error(success, command_name, error_message)

  Sends an error to the player and logs the error, used with pcall within command handler please avoid direct use nb: use error(error_message) within your callback to trigger do not trigger directly as code exictuion may still continue

  Parameters:
  - success : (boolean) the success value returned from pcall, or just false to trigger error
  - command_name : (string) the name of the command this is used within the log
  - error_message : (string) the error returned by pcall or some other error, this is logged and not returned to player
  Returns:
  - (boolean) the opposite of success so true means to cancel execution, used internally
  Usage:

      -- Used in the command system to log handler errors
      local success, err = pcall(command_data.callback, player, unpack(params))
      if Commands.internal_error(success, command_data.name, err) then
          return command_log(player, command_data, 'Internal Error: Command Callback Fail', raw_params, command_event.parameter, err)
      end

# success([value])

  Sends a value to the player, followed by a command complete message nb: returning any value from your callback will trigger this function, return this function to prevent duplicate messages

  Parameters:
  - value : (any) the value to return to the player, if nil then only success message returned (optional)
  Returns:
  - (Commands.defines.success) return this to the command handler to prevent two success messages
  Usage:

      -- Print a custom success message
      return Commands.success('Your message has been printed')

      -- Returning the value has the same result
      return 'Your message has been printed'

# print(value, colour)

  Sends a value to the player, different to success as this does not signal the end of your command

  Parameters:
  - value : (any) the value that you want to return to the player
  - colour : (table) the colour of the message that the player sees
  Usage:

      -- Output a message to the player
      Commands.print('Your command is in progress')

# run_command(command_event)

  Main event function that is ran for all commands, used internally please avoid direct use

  Parameters:
  - command_event : (table) passed directly from command event from the add_command function
  Usage:

      Commands.run_command(event)