--
-- hook.lua
--
-- Written by [aka]bomb, 2022
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy of
-- this software and associated documentation files (the "Software"), to deal in
-- the Software without restriction, including without limitation the rights to
-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-- of the Software, and to permit persons to whom the Software is furnished to do
-- so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in all
-- copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-- SOFTWARE.
--
local hook = {}
local error = error
local print = print
local string_format = string.format
local tostring = tostring
hook.hooks = {}
local hook_hooks = hook.hooks
function hook.add(eventname, hookname, func)
    if type(func) ~= "function" then
        error("bad argument #3 (function expected, got " .. type(func) .. ')')
    end
    local ehooks = hook_hooks[eventname]
    if ehooks == nil then
        hook_hooks[eventname] = {
            { hookname, func }
        }
    else
        table.insert(ehooks, { hookname, func })
    end
end
function hook.call(eventname, ...)
    local ehooks = hook_hooks[eventname]
    if ehooks == nil then return end
    for i=1,#ehooks do
        local v = ehooks[i][2](...)
        if v ~= nil then return v end
    end
end
function hook.remove(eventname, hookname)
    local ehooks = hook_hooks[eventname]
    if ehooks == nil then return end
    for i=1,#ehooks do
        if ehooks[i][1] == hookname then
            ehooks[i] = nil
            break
        end
    end
end
function hook.print(eventname)
    local ehooks = hook_hooks[eventname]
    if ehooks == nil then return end
    if #ehooks == 0 then
        print("event '" .. eventname .. "' has no attached hooks")
        return
    end
    for i=1,#ehooks do
        local h = ehooks[i]
        print(string_format("%d.\t%s\t%s", i, tostring(h[1]), tostring(h[2])))
    end
end
return hook