-- luacheck: ignore
-- https://github.com/APItools/router.lua
local router = {
    _VERSION     = 'router.lua v2.1.0',
    _DESCRIPTION = 'A simple router for Lua',
    _LICENSE     = [[
      MIT LICENSE
      * Copyright (c) 2013 Enrique García Cota
      * Copyright (c) 2013 Raimon Grau
      * Copyright (c) 2015 Lloyd Zhou
      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 COLON_BYTE = string.byte(':', 1)
  local WILDCARD_BYTE = string.byte('*', 1)
  local HTTP_METHODS = {'get', 'post', 'put', 'patch', 'delete', 'trace', 'connect', 'options', 'head'}
  
  local function match_one_path(node, path, f)
    for token in path:gmatch("[^/.]+") do
      if WILDCARD_BYTE == token:byte(1) then
        node['WILDCARD'] = {['LEAF'] = f, ['TOKEN'] = token:sub(2)}
        return
      end
      if COLON_BYTE == token:byte(1) then -- if match the ":", store the param_name in "TOKEN" array.
        node['TOKEN'] = node['TOKEN'] or {}
        token = token:sub(2)
        node = node['TOKEN']
      end
      node[token] = node[token] or {}
      node = node[token]
    end
    node["LEAF"] = f
  end
  
  local function resolve(path, node, params)
    local _, _, current_token, rest = path:find("([^/.]+)(.*)")
    if not current_token then
      if node['WILDCARD'] then
        params[node['WILDCARD']['TOKEN']] = ""
        return node['WILDCARD']['LEAF'], params
      end
      return node["LEAF"], params
    end

    if node['WILDCARD'] then
    params[node['WILDCARD']['TOKEN']] = current_token .. rest
    return node['WILDCARD']['LEAF'], params
    end

    if node[current_token] then
    local f, bindings = resolve(rest, node[current_token], params)
    if f then return f, bindings end
    end

    for param_name, child_node in pairs(node['TOKEN'] or {}) do
    local param_value = params[param_name]
    params[param_name] = current_token or param_value -- store the value in params, resolve tail path

    local f, bindings = resolve(rest, child_node, params)
    if f then return f, bindings end

    params[param_name] = param_value -- reset the params table.
    end

    return false
  end
  
  local function merge(destination, origin, visited)
    if type(origin) ~= 'table' then return origin end
    if visited[origin] then return visited[origin] end
    if destination == nil then destination = {} end
  
    for k,v in pairs(origin) do
      k = merge(nil, k, visited) -- makes a copy of k
      if destination[k] == nil then
        destination[k] = merge(nil, v, visited)
      end
    end
  
    return destination
  end
  
  local function merge_params(...)
    local params_list = {...}
    local result, visited = {}, {}
  
    for i=1, #params_list do
      merge(result, params_list[i], visited)
    end
  
    return result
  end
  
  ------------------------------ INSTANCE METHODS ------------------------------------
  local Router = {}
  
  function Router:resolve(method, path, ...)
    local node   = self._tree[method]
    if not node then return nil, ("Unknown method: %s"):format(tostring(method)) end
    return resolve(path, node, merge_params(...))
  end
  
  function Router:execute(method, path, ...)
    local f,params = self:resolve(method, path, ...)
    if not f then return nil, ('Could not resolve %s %s - %s'):format(tostring(method), tostring(path), tostring(params)) end
    return true, f(params)
  end
  
  function Router:match(method, path, fun)
    if type(method) == 'string' then -- always make the method to table.
      method = {method}
    end
  
    local parsed_methods = {}
    for k, v in pairs(method) do
      if type(v) == 'string' then
        -- convert shorthand methods into longhand
        if parsed_methods[v] == nil then parsed_methods[v] = {} end
        parsed_methods[v][path] = fun
      else
        -- pass methods already in longhand format onwards
        parsed_methods[k] = v
      end
    end
  
    for m, routes in pairs(parsed_methods) do
      for p, f in pairs(routes) do
        if not self._tree[m] then self._tree[m] = {} end
        match_one_path(self._tree[m], p, f)
      end
    end
  end
  
  for _,method in ipairs(HTTP_METHODS) do
    Router[method] = function(self, path, f)  -- Router.get = function(self, path, f)
      self:match(method:upper(), path, f)     --   return self:match('GET', path, f)
    end                                       -- end
  end
  
  Router['any'] = function(self, path, f) -- match any method
    for _,method in ipairs(HTTP_METHODS) do
      self:match(method:upper(), path, function(params) return f(params, method) end)
    end
  end
  
  local router_mt = { __index = Router }
  
  ------------------------------ PUBLIC INTERFACE ------------------------------------
  router.new = function()
    return setmetatable({ _tree = {} }, router_mt)
  end
  
  return router