--
-- melisma - extensible and scriptable audio engine
-- Copyright (C) 2026  Ludvig Gunne Lindström
--
-- This program 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 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
--

local m_util = require 'melisma.util'

local M = {}

function M.fmap(f,l)
  local res = {}
  for k,v in pairs(l) do res[k] = f(v) end
  return res
end

function M.compose(f,g,...)
  local tail = table.pack(...)
  if g == nil then return f end
  return function(x) return f(M.compose(g,table.unpack(tail))(x)) end
end

function M.pipeline(...)
  local args = table.pack(...)
  return function(x)
    for _,f in ipairs(args) do x = f(x) end
    return x
  end
end

function M.bind(f,...)
  local bound = table.pack(...)
  return function(...)
    local free = table.pack(...)
    local all = M.concat(bound,free)
    return f(table.unpack(all))
  end
end

function M.bind1(f,...)
  local bound = table.pack(...)
  return function(x)
    return f(x,table.unpack(bound))
  end
end

function M.constval(v) return function(...) return v end end

function M.constfunc(f) return function(...) f() end end

function M.call(f,...) return f(...) end

function M.replicate(f,n)
  local res = {}
  for i=1,n do
    if type(f) == 'function' then
      table.insert(res,f())
    else
      table.insert(res,f)
    end
  end
  return res
end

function M.id(...) return ... end

function M.access(...)
  local args = table.pack(...)
  local x = args[#args]
  args[#args] = nil

  for _,key in ipairs(args) do
    x = x[key]
  end

  return x
end

function M.filter(pred,list)
  local result = {}

  for _,elem in ipairs(list) do
    if pred(elem) then
      table.insert(result,elem)
    end
  end

  return result
end

function M.void(...) end

function M.zip(f,lhs,rhs)
  local result = {}
  local n = math.min(#lhs,#rhs)

  for i = 1,n do
    local v = f(lhs[i],rhs[i])
    table.insert(result,v)
  end

  return result
end

function M.tap(f)
  return function(...)
    f(...)
    return ...
  end
end

function M.fold(mempty,mappend,tbl)
	local result = mempty
	for i = 1,#tbl do result = mappend(result,tbl) end
	return result
end

function M.flatten(tbl)
	if type(tbl) ~= 'table' then return tbl end
	return M.fold({}, M.concat, fmap(M.flatten, tbl))
end

function M.concat(lhs,rhs)
  local result = {}
  for i = 1,#lhs do result[i] = lhs[i] end
  for i = 1,#rhs do result[i + #lhs] = rhs[i] end
  return result
end

function M.find(list,pred)
  for i = 1,#list do
    if pred(list[i]) then return list[i],i end
  end
  return nil,nil
end

function M.range(f,t,s)
  local res = {}
  for x = f,t,s or 1 do table.insert(res,x) end
  return res
end

function M.image(a,b,c,d,x) return (x - a)/(b - a)*(d - c) + c end

function M.apply(f,...) return f(...) end

function M.once(f)
  local ret
  local called = false
  return function(...)
    if not called then
      ret = f(...)
      called = true
      return ret
    end
  end
end

return M