## Commands core

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

### Usage

    ---- Example Authenticator:
        -- The command system is most useful when you can control who can use 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 some commands to require the user to be a game admin:

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

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

        -- Although no return is required to allow the command to execute 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 to mean any one can use it
        -- 2) when the "admin_only" flag is set, and the player is admin

        -- Now when the user is not an admin and the command requires you to be an admin then we must reject the request:
        -- 1) return false -- this is the most basic block and should only be used while testing
        -- 2) return reject -- returning the reject function is only an option as a fail safe, same as returning false
        -- 3) reject() -- this will block execution without returning to allow further code to be ran in the 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 code before rejecting

        -- Example Code:
        Commands.add_authenticator(function(player,command,flags,reject)
            if flags.admin_only then -- our test for the "admin_only" flag
                if player.admin then
                    return true -- true return 2
                else
                    return reject('This command is for admins only!') -- reject return 5 with a custom error message
                end
            else
                return true -- true return 1
            end
        end)

    ---- Example Parse:
        -- Before you go making commands 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 by an handler so before your
        -- command is ever executed you can be sure that all the params are valid. This module should be 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
        -- Example parse usage:
        :add_param('repeat_count',false,'number-range-int',5,10) -- range 5 to 10 inclusive

        -- The command parse will be passed 3 params and any other you define, in our case:
        -- 1) 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) the player who is using the command, this is always present
        -- 3) the reject function to throw an error to the user, this is always present
        -- 4) the range min, this is user defined and has the value given when the param is defined
        -- 5) the range max, this is user defined and has the value given when the param is defined

        -- When returning from the param parse you again 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 callback is blocked, 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 the the user
        -- nb: if you do not return reject after you call it then you are still returning nil so there will be a duplicate message

        -- It should be noted that if you want to expand on an existing parse you can use Commands.parse(type,input,player,reject)
        -- and this value will either return a new value for the input or nil, if it is nil you should return nil to prevent double
        -- 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)

    ---- 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)

        -- Some other useful functions that can be used are:
        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 Code:
        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)

### Dependencies

utils.game
expcore.common

### 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 not included
search(keyword[, allowed_player]) | Searches command names and help messages to find possible commands, game commands included

### Parse

add_parse(name, callback) | Adds a parse function which can be called by name rather than callback (used in add_param) nb: this is not needed 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
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) | Adds default values to params only matters if the param is optional, if default value is a function it is called with param player
Commands._prototype:set_flag(name, value) | 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 /tp with both working
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 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]) | Sends an error message to the player and returns a constant to return to command handler to exit execution nb: this is for non fatal errors meaning there is no log of this event nb: if reject is giving as a param to the callback use that instead
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 the handler may still continue
success([value]) | Sends a value to the player, followed by a command complete message nb: either return a value from your callback to trigger or return the return of this to prevent two messages
run_command(command_event) | Main event function that is ran for all commands, used internally please avoid direct use

### Dependencies

# utils.game
# expcore.common

### 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 callback param - player: LuaPlayer - the player who is trying to use the command callback param - command: string - the name of the command which is being used callback param - flags: table - any flags which have been set for the command callback param - reject: function(error_message?: string) - call to fail authorize with optional error message
  Returns:
  - (number) the index it was inserted at use to remove the callback, if anon function used
# 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) was the callback found and removed
# 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

### Getters

# get([player])

  Gets all commands that a player is allowed to use, game commands 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
# search(keyword[, allowed_player])

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

  Parameters:
  - keyword : (string) the word which you are trying to find
  - allowed_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

### Parse

# add_parse(name, callback)

  Adds a parse function which can be called by name rather than callback (used in add_param) nb: this is not needed 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 parse param - input: string - the input given by the user for this param parse param - player: LuaPlayer - the player who is using the command parse param - reject: function(error_message) - use this function to send a error to the user and fail running parse return - the value that will be passed to the command callback, must not be nil and if reject then command is not run
  Returns:
  - (boolean) was the parse added will be false if the name is already used
# remove_parse(name)

  Removes a parse function, see add_parse for adding them

  Parameters:
  - name : (string) the name of the parse to remove
# 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 and cant be a function
  - input : (string) string the input to pass to the parse, will always be a but might not be the original input
  - player : (LuaPlayer) the player that is calling 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

### Creation

# new_command(name, help)

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

  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
# 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 parse param - input: string - the input given by the user for this param parse param - player: LuaPlayer - the player who is using the command parse param - reject: function(error_message) - use this function to send a error to the user and fail running parse return - the value that will be passed to the command callback, must not be nil and if reject then command is not run (optional)
  Returns:
  - (Commands._prototype) pass through to allow more functions to be called
# Commands._prototype:set_defaults(defaults)

  Adds default values to params only matters if the param is optional, if default value is a function it is called with param player

  Parameters:
  - defaults : (table) table a keyed by the name of the param with the value as the default value {paramName=defaultValue} callback param - player: LuaPlayer - the player using the command, default value does not need to be a function callback
  Returns:
  - (Commands._prototype) pass through to allow more functions to be called
# Commands._prototype:set_flag(name, value)

  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; used to keep flags separate
  - value : (any) the tag that you want can be anything that the authenticators are expecting nb: if value is nil then name will be assumed as the value and added at a numbered index
  Returns:
  - (Commands._prototype) pass through to allow more functions to be called
# Commands._prototype:add_alias(any)

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

  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:

      command:add_alias('aliasOne','aliasTwo','etc')

# 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
# Commands._prototype:register(callback)

  Adds the callback to the command and registers all aliases, params and help message with the game 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 callback param - player: LuaPlayer - the player who used the command callback param - ... - any params which were registered with add_param in the order they where registered callback param - raw: string - the raw input from the user, comes after every param added with add_param

### Status

# error([error_message][, play_sound])

  Sends an error message to the player and returns a constant to return to command handler to exit execution nb: this is for non fatal errors meaning there is no log of this event nb: if reject is giving as a param to the callback use that instead

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

      return Commands.error()

# 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 the handler 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
# success([value])

  Sends a value to the player, followed by a command complete message nb: either return a value from your callback to trigger or return the return of this to prevent two 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
# 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