-------------------------------------------------------------
-- Mana Support Library                                    --
--                                                         --
-- Functions which are called by the game engine and       --
-- helper functions useful for writing other scripts.      --
--                                                         --
----------------------------------------------------------------------------------
--  Copyright 2008 The Mana World Development Team                              --
--                                                                              --
--  This file is part of The Mana Server.                                       --
--                                                                              --
--  The Mana Server is free software; you can redistribute  it and/or modify it --
--  under the terms of the GNU General  Public License as published by the Free --
--  Software Foundation; either version 2 of the License, or any later version. --
----------------------------------------------------------------------------------

require "scripts/lua/libmana-constants"

-- Array containing the function registered by atinit.
local init_fun = {}

-- Table of scheduled jobs. A job is an array with 3 elements:
-- 0: the UNIX timestamp when it is executed
-- 1: the function which is executed
-- 2: nil when it is a one-time job. Repetition interval is seconds when it is
--    a repeated job.
local scheduler_jobs = {}

-- checks for jobs which have to be executed, executes them and reschedules
-- them when they are repeated jobs.
local function check_schedule()
  local current_time = os.time()

  while #scheduler_jobs~=0 and current_time > scheduler_jobs[#scheduler_jobs][0] do
    -- retreive the job and remove it from the schedule
    job = scheduler_jobs[#scheduler_jobs]
    table.remove(scheduler_jobs)
    -- reschedule the job when it is a repeated job
    if job[2] then
        schedule_every(job[2], job[1])
    end
    -- execute the job
    job[1]()
  end
end

-- Registered as the function to call every tick.
-- Checks for scheduled function calls and cleans obsolete connections.
local function update()
  check_schedule()
end

-- Registers a function so that is is executed during map initialization.
function atinit(f)
  init_fun[#init_fun + 1] = f
end

-- Called by the game for creating NPCs embedded into maps.
-- Delays the creation until map initialization is performed.
-- Note: Assumes that the "npc_handler" global field contains the NPC handler.
local function create_npc_delayed(name, id, gender, x, y)
  -- Bind the name to a local variable first, as it will be reused.
  local h = npc_handler
  atinit(function() mana.npc_create(name, id, gender, x, y, h) end)
  npc_handler = nil
end

-- Called during map initialization, for each map.
-- Executes all the functions registered by atinit.
local function map_initialize()
  for i,f in ipairs(init_fun) do
    f()
  end
  init_fun = {}
end


-- SCHEDULER

-- compare function used to sort the scheduler_jobs table.
-- the jobs which come first are at the end of the table.
local function job_cmp(job1, job2)
  return (job1[0] > job2[0])
end

-- schedules a function call to be executed once in n seconds
function schedule_in(seconds, funct)
  local job = {}
  job[0] = os.time() + seconds
  job[1] = funct
  job[2] = nil
  table.insert(scheduler_jobs, job)
  table.sort(scheduler_jobs, job_cmp)
end

-- schedules a function call to be executed at regular intervals of n seconds
function schedule_every(seconds, funct)
  local job = {}
  job[0] = os.time() + seconds
  job[1] = funct
  job[2] = seconds
  table.insert(scheduler_jobs, job)
  table.sort(scheduler_jobs, job_cmp)
end

-- schedules a function call to be executed at a given date
function schedule_per_date(my_year, my_month, my_day, my_hour, my_minute, funct)
  local job = {}
  job[0] = os.time{year = my_year, month = my_month, day = my_day,
                   hour = my_hour, min = my_minute}
  job[1] = funct
  job[2] = nil
  table.insert(scheduler_jobs, job)
  table.sort(scheduler_jobs, job_cmp)
end

-- MAP/WORLD VARIABLES NOTIFICATIONS
local onmapvar_functs = {}
local onworldvar_functs = {}

local function on_mapvar_callback(key, value)
  local functs = onmapvar_functs[key]
  local mapid = mana.get_map_id()
  for func, map in pairs(functs) do
    if map == mapid then
      func(key, value)
    end
  end
end

local function on_worldvar_callback(key, value)
  local functs = onworldvar_functs[key]
  for func, _ in pairs(functs) do
    func(key, value)
  end
end

function on_mapvar_changed(key, funct)
  if not onmapvar_functs[key] then
    onmapvar_functs[key] = {}
    mana.on_mapvar_changed(key, on_mapvar_callback)
  end
  onmapvar_functs[key][funct] = mana.get_map_id()
end

function on_worldvar_changed(key, funct)
  if not onworldvar_functs[key] then
    onworldvar_functs[key] = {}
    mana.on_worldvar_changed(key, on_worldvar_callback)
  end
  onworldvar_functs[key][funct] = true
end

function remove_mapvar_listener(key, funct)
  onmapvar_functs[key][funct] = nil
end

function remove_worldvar_listener(key, funct)
  onworldvar_functs[key][funct] = nil
end

-- DEATH NOTIFICATIONS
local ondeath_functs = {}
local onremove_functs = {}

-- requests the gameserver to notify the script engine when the being
-- dies and adds a script function to be executed in this case.
function on_death(being, funct)
  if ondeath_functs[being] == nil then
    ondeath_functs[being] = {}
  end
  table.insert(ondeath_functs[being], funct)
  mana.being_register(being)
end

-- requests the gameserver to notify the script engine when the being
-- dies and adds a script function to be executed in this case.
function on_remove(being, funct)
  if onremove_functs[being] == nil then
    onremove_functs[being] = {}
  end
  table.insert(onremove_functs[being], funct)
  mana.being_register(being)
end

-- Registered as callback for when a registered being dies.
local function death_notification(being)
  if type(ondeath_functs[being]) == "table" then
    for i,funct in pairs(ondeath_functs[being]) do
      funct()
    end
    ondeath_functs[being] = nil
  end
end

-- Registered as callback for when a registered being is removed.
local function remove_notification(being)
  if type(onremove_functs[being]) == "table" then
    for i,funct in pairs(onremove_functs[being]) do
      funct()
    end
    onremove_functs[being] = nil
    ondeath_functs[being] = nil
  end
end


-- Below are some convenience methods added to the engine API
mana.chr_money_change = function(ch, amount)
  mana.being_set_base_attribute(
                            ch,
                            ATTR_GP,
                            mana.being_get_base_attribute(ch, ATTR_GP) + amount)
end

mana.chr_money = function(ch)
  return mana.being_get_base_attribute(ch, ATTR_GP)
end

-- Register callbacks
mana.on_update(update)

mana.on_create_npc_delayed(create_npc_delayed)
mana.on_map_initialize(map_initialize)

mana.on_being_death(death_notification)
mana.on_being_remove(remove_notification)