--[[
Copyright (c) 2012-2013 Kaarle Ritvanen
See LICENSE file for license details
--]]

local M = {}

local err = require('acf2.error')
local raise = err.raise

local node = require('acf2.model.node')

local object = require('acf2.object')
local class = object.class
local super = object.super

local util = require('acf2.util')
local map = util.map
local setdefaults = util.setdefaults


M.Member = class()

function M.Member:init(params)
   for k, v in pairs(params or {}) do
      if self[k] == nil then self[k] = v end
   end
end

function M.Member:auto_ui_name(name)
   if not name then return end
   local res = (name:sub(1, 1):upper()..name:sub(2)):gsub('-', ' ')
   return res
end

function M.Member:meta(context)
   return {
      name=self.name,
      description=self.description,
      ['ui-name']=self.ui_name or self:auto_ui_name(self.name)
   }
end


function M.conv_filter(filter)
   return filter and map(
      function(values)
	 return type(values) == 'table' and values or {values}
      end,
      filter
   ) or nil
end


M.Field = class(M.Member)

function M.Field:init(params)
   if not params then params = {} end
   params = setdefaults(
      params,
      {
	 addr=params.compute and node.null_addr or nil,
	 editable=not params.compute
      }
   )

   super(self, M.Field):init(params)

   if type(self.editable) ~= 'function' then
      function self.editable(context) return params.editable end
   end

   self.condition = M.conv_filter(self.condition)

   if self.choice then
      self.choice = map(
	 function(choice)
	    if type(choice) ~= 'table' then choice = {choice} end
	    for i, k in ipairs{'value', 'ui-value'} do
	       if choice[i] then
		  assert(not choice[k])
		  choice[k] = choice[i]
		  choice[i] = nil
	       end
	    end
	    return setdefaults(
	       choice,
	       {enabled=true, ['ui-value']=self:auto_ui_name(choice.value)}
	    )
	 end,
	 self.choice
      )
   end

   if not self.widget then
      self.widget = self.choice and 'combobox' or 'field'
   end
end

function M.Field:_choice(context) return self.choice end

function M.Field:meta(context)
   assert(self.dtype)
   local res = super(self, M.Field):meta(context)

   res.type = self.dtype
   res.editable = self:editable(context)
   res.condition = self.condition
   res.required = self.required
   res.default = self.default
   res.choice = self:_choice(context)
   res.widget = self.widget

   return res
end

function M.Field:topology(context)
   return {
      {path=context.path, addr=context.addr, type=self.dtype}
   }
end

function M.Field:load(context)
   if not context.txn then return setmetatable({}, context) end
   local value
   if self.compute then value = self:compute(context) end
   if value == nil then value = self:_load(context) end
   if value == nil then return self.default end
   return value
end

function M.Field:_load(context) return context.txn:get(context.addr) end

function M.Field:_validate(context, value)
   if value == nil then
      self:check_required(context)
      return
   end

   local save
   value, save = self:normalize(context, value)

   local committing = context.txn:committing()
   local choice = self:_choice(context)
   if choice and not util.contains(
      map(
	 function(ch) return ch.value end,
	 util.filter(function(ch) return committing or ch.enabled end, choice)
      ),
      value
   ) then
      raise(context.path, 'Invalid value')
   end

   self:validate(context, value)

   if save == nil then save = value end
   return save
end

function M.Field:check_editable(context)
   if not self:editable(context) then
      raise(context.path, 'Is not editable')
   end
end

function M.Field:check_required(context)
   if self.required then raise(context.path, 'Required value not set') end
end

function M.Field:normalize(context, value) return value end

function M.Field:validate(context, value) end

function M.Field:save(context, value)
   self:check_editable(context)
   self:_save(context, self:_validate(context, value))
end

function M.Field:_save(context, value) context.txn:set(context.addr, value) end

function M.Field:validate_saved(context)
   if self:editable(context) then self:save(context, self:load(context)) end
end


local Primitive = class(M.Field)

function Primitive:validate(context, value)
   local t = self.dtype
   if type(value) ~= t then raise(context.path, 'Not a '..t) end
end


M.String = class(Primitive)

function M.String:init(params)
   super(self, M.String):init(params)
   self.dtype = 'string'
end

function M.String:validate(context, value)
   super(self, M.String):validate(context, value)
   if self['max-length'] and value:len() > self['max-length'] then
      raise(context.path, 'Maximum length exceeded')
   end
   if self.pattern and not value:match('^'..self.pattern..'$') then
      raise(context.path, 'Invalid value')
   end
end

function M.String:meta(context)
   local res = super(self, M.String):meta(context)
   res['max-length'] = self['max-length']
   return res
end


M.Number = class(Primitive)

function M.Number:init(params)
   super(self, M.Number):init(params)
   self.dtype = 'number'
end

function M.Number:normalize(context, value)
   return value and tonumber(value) or value
end


M.Integer = class(M.Number)

function M.Integer:validate(context, value)
   super(self, M.Integer):validate(context, value)
   if math.floor(value) ~= value then raise(context.path, 'Not an integer') end
end


M.Boolean = class(Primitive)

function M.Boolean:init(params)
   super(self, M.Boolean):init(params)
   self.dtype = 'boolean'
   self.widget = self.dtype
end


M.TreeNode = class(M.Field)

function M.TreeNode:init(params)
   if not params.widget then params.widget = 'link' end
   super(self, M.TreeNode):init(params)
end

function M.TreeNode:topology(context)
   local res = super(self, M.TreeNode):topology(context)
   res[1].type = 'table'
   util.extend(res, node.topology(self:load(context, {create=true})))
   return res
end

function M.TreeNode:load(context, options)
   if context.txn and not (
      (
	 options and options.create
      ) or self.create or self:_load(context)
   ) then return end
   return self.itype(context, self.iparams)
end

function M.TreeNode:save(context, value)
   self:check_editable(context)

   local path = context.path

   if value == path then return end
   if type(value) == 'string' then value = context.txn:fetch(value) end
   if object.isinstance(value, node.TreeNode) and node.path(value) == path then
      return
   end

   self:_save(context)

   if value then
      if type(value) ~= 'table' then
	 raise(path, 'Cannot assign primitive value')
      end

      self:_save(context, {})
      local new = self:load(context, {create=true})

      local errors = err.ErrorDict()
      for k, v in node.pairs(value) do
	 errors:collect(self.save_member, new, k, v)
      end
      errors:raise()
   end
end

function M.TreeNode.save_member(node, k, v) node[k] = v end

function M.TreeNode:validate_saved(context)
   if self:load(context) == nil then self:check_required(context) end
end


M.Model = class(M.TreeNode)

function M.Model:init(params)
   super(self, M.Model):init(params)

   assert(self.model)
   self.itype = self.model
   self.dtype = 'model'
end


return M