--[[
LuCI - Configuration Bind Interface

Description:
Offers an interface for binding configuration values to certain
data types. Supports value and range validation and basic dependencies.

FileId:
$Id$

License:
Copyright 2008 Steven Barth <steven@midlink.org>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

]]--
module("luci.cbi", package.seeall)

require("luci.template")
require("luci.util")
require("luci.http")
require("luci.model.uci")

local uci        = luci.model.uci
local class      = luci.util.class
local instanceof = luci.util.instanceof


-- Loads a CBI map from given file, creating an environment and returns it
function load(cbimap)
	require("luci.fs")
	require("luci.i18n")
	require("luci.config")
	require("luci.sys")

	local cbidir = luci.sys.libpath() .. "/model/cbi/"
	local func, err = loadfile(cbidir..cbimap..".lua")

	if not func then
		return nil
	end

	luci.i18n.loadc("cbi")

	luci.util.resfenv(func)
	luci.util.updfenv(func, luci.cbi)
	luci.util.extfenv(func, "translate", luci.i18n.translate)
	luci.util.extfenv(func, "translatef", luci.i18n.translatef)

	local maps = {func()}

	for i, map in ipairs(maps) do
		if not instanceof(map, Map) then
			error("CBI map returns no valid map object!")
			return nil
		end
	end

	return maps
end

-- Node pseudo abstract class
Node = class()

function Node.__init__(self, title, description)
	self.children = {}
	self.title = title or ""
	self.description = description or ""
	self.template = "cbi/node"
end

-- i18n helper
function Node._i18n(self, config, section, option, title, description)

	-- i18n loaded?
	if type(luci.i18n) == "table" then

		local key = config:gsub("[^%w]+", "")

		if section then	key = key .. "_" .. section:lower():gsub("[^%w]+", "") end
		if option  then key = key .. "_" .. option:lower():gsub("[^%w]+", "")  end

		self.title = title or luci.i18n.translate( key, option or section or config )
		self.description = description or luci.i18n.translate( key .. "_desc", "" )
	end
end

-- Append child nodes
function Node.append(self, obj)
	table.insert(self.children, obj)
end

-- Parse this node and its children
function Node.parse(self, ...)
	for k, child in ipairs(self.children) do
		child:parse(...)
	end
end

-- Render this node
function Node.render(self, scope)
	scope = scope or {}
	scope.self = self

	luci.template.render(self.template, scope)
end

-- Render the children
function Node.render_children(self, ...)
	for k, node in ipairs(self.children) do
		node:render(...)
	end
end


--[[
A simple template element
]]--
Template = class(Node)

function Template.__init__(self, template)
	Node.__init__(self)
	self.template = template
end


--[[
Map - A map describing a configuration file
]]--
Map = class(Node)

function Map.__init__(self, config, ...)
	Node.__init__(self, ...)
	Node._i18n(self, config, nil, nil, ...)

	self.config = config
	self.template = "cbi/map"
	if not uci.load(self.config) then
		error("Unable to read UCI data: " .. self.config)
	end
end

-- Use optimized UCI writing
function Map.parse(self, ...)
	Node.parse(self, ...)
	uci.save(self.config)
	uci.unload(self.config)
end

-- Creates a child section
function Map.section(self, class, ...)
	if instanceof(class, AbstractSection) then
		local obj  = class(self, ...)
		self:append(obj)
		return obj
	else
		error("class must be a descendent of AbstractSection")
	end
end

-- UCI add
function Map.add(self, sectiontype)
	return uci.add(self.config, sectiontype)
end

-- UCI set
function Map.set(self, section, option, value)
	if option then
		return uci.set(self.config, section, option, value)
	else
		return uci.set(self.config, section, value)
	end
end

-- UCI del
function Map.del(self, section, option)
	if option then
		return uci.delete(self.config, section, option)
	else
		return uci.delete(self.config, section)
	end
end

-- UCI get
function Map.get(self, section, option)
	if not section then
		return uci.get_all(self.config)
	elseif option then
		return uci.get(self.config, section, option)
	else
		return uci.get_all(self.config, section)
	end
end


--[[
AbstractSection
]]--
AbstractSection = class(Node)

function AbstractSection.__init__(self, map, sectiontype, ...)
	Node.__init__(self, ...)
	self.sectiontype = sectiontype
	self.map = map
	self.config = map.config
	self.optionals = {}

	self.optional = true
	self.addremove = false
	self.dynamic = false
end

-- Appends a new option
function AbstractSection.option(self, class, option, ...)
	if instanceof(class, AbstractValue) then
		local obj  = class(self.map, option, ...)

		Node._i18n(obj, self.config, self.section or self.sectiontype, option, ...)

		self:append(obj)
		return obj
	else
		error("class must be a descendent of AbstractValue")
	end
end

-- Parse optional options
function AbstractSection.parse_optionals(self, section)
	if not self.optional then
		return
	end

	self.optionals[section] = {}

	local field = luci.http.formvalue("cbi.opt."..self.config.."."..section)
	for k,v in ipairs(self.children) do
		if v.optional and not v:cfgvalue(section) then
			if field == v.option then
				field = nil
			else
				table.insert(self.optionals[section], v)
			end
		end
	end

	if field and #field > 0 and self.dynamic then
		self:add_dynamic(field)
	end
end

-- Add a dynamic option
function AbstractSection.add_dynamic(self, field, optional)
	local o = self:option(Value, field, field)
	o.optional = optional
end

-- Parse all dynamic options
function AbstractSection.parse_dynamic(self, section)
	if not self.dynamic then
		return
	end

	local arr  = luci.util.clone(self:cfgvalue(section))
	local form = luci.http.formvaluetable("cbid."..self.config.."."..section)
	for k, v in pairs(form) do
		arr[k] = v
	end

	for key,val in pairs(arr) do
		local create = true

		for i,c in ipairs(self.children) do
			if c.option == key then
				create = false
			end
		end

		if create and key:sub(1, 1) ~= "." then
			self:add_dynamic(key, true)
		end
	end
end

-- Returns the section's UCI table
function AbstractSection.cfgvalue(self, section)
	return self.map:get(section)
end

-- Removes the section
function AbstractSection.remove(self, section)
	return self.map:del(section)
end

-- Creates the section
function AbstractSection.create(self, section)
	return self.map:set(section, nil, self.sectiontype)
end



--[[
NamedSection - A fixed configuration section defined by its name
]]--
NamedSection = class(AbstractSection)

function NamedSection.__init__(self, map, section, type, ...)
	AbstractSection.__init__(self, map, type, ...)
	Node._i18n(self, map.config, section, nil, ...)

	self.template = "cbi/nsection"
	self.section = section
	self.addremove = false
end

function NamedSection.parse(self)
	local s = self.section
	local active = self:cfgvalue(s)


	if self.addremove then
		local path = self.config.."."..s
		if active then -- Remove the section
			if luci.http.formvalue("cbi.rns."..path) and self:remove(s) then
				return
			end
		else           -- Create and apply default values
			if luci.http.formvalue("cbi.cns."..path) and self:create(s) then
				for k,v in pairs(self.children) do
					v:write(s, v.default)
				end
			end
		end
	end

	if active then
		AbstractSection.parse_dynamic(self, s)
		if luci.http.formvalue("cbi.submit") then
			Node.parse(self, s)
		end
		AbstractSection.parse_optionals(self, s)
	end
end


--[[
TypedSection - A (set of) configuration section(s) defined by the type
	addremove: 	Defines whether the user can add/remove sections of this type
	anonymous:  Allow creating anonymous sections
	validate: 	a validation function returning nil if the section is invalid
]]--
TypedSection = class(AbstractSection)

function TypedSection.__init__(self, map, type, ...)
	AbstractSection.__init__(self, map, type, ...)
	Node._i18n(self, map.config, type, nil, ...)

	self.template  = "cbi/tsection"
	self.deps = {}
	self.excludes = {}

	self.anonymous = false
end

-- Return all matching UCI sections for this TypedSection
function TypedSection.cfgsections(self)
	local sections = {}
	uci.foreach(self.map.config, self.sectiontype,
		function (section)
			if self:checkscope(section[".name"]) then
				table.insert(sections, section[".name"])
			end
		end)

	return sections
end

-- Creates a new section of this type with the given name (or anonymous)
function TypedSection.create(self, name)
	if name then
		self.map:set(name, nil, self.sectiontype)
	else
		name = self.map:add(self.sectiontype)
	end

	for k,v in pairs(self.children) do
		if v.default then
			self.map:set(name, v.option, v.default)
		end
	end
end

-- Limits scope to sections that have certain option => value pairs
function TypedSection.depends(self, option, value)
	table.insert(self.deps, {option=option, value=value})
end

-- Excludes several sections by name
function TypedSection.exclude(self, field)
	self.excludes[field] = true
end

function TypedSection.parse(self)
	if self.addremove then
		-- Create
		local crval = "cbi.cts." .. self.config .. "." .. self.sectiontype
		local name  = luci.http.formvalue(crval)
		if self.anonymous then
			if name then
				self:create()
			end
		else
			if name then
				-- Ignore if it already exists
				if self:cfgvalue(name) then
					name = nil;
				end

				name = self:checkscope(name)

				if not name then
					self.err_invalid = true
				end

				if name and name:len() > 0 then
					self:create(name)
				end
			end
		end

		-- Remove
		crval = "cbi.rts." .. self.config
		name = luci.http.formvaluetable(crval)
		for k,v in pairs(name) do
			if self:cfgvalue(k) and self:checkscope(k) then
				self:remove(k)
			end
		end
	end

	for i, k in ipairs(self:cfgsections()) do
		AbstractSection.parse_dynamic(self, k)
		if luci.http.formvalue("cbi.submit") then
			Node.parse(self, k)
		end
		AbstractSection.parse_optionals(self, k)
	end
end

-- Verifies scope of sections
function TypedSection.checkscope(self, section)
	-- Check if we are not excluded
	if self.excludes[section] then
		return nil
	end

	-- Check if at least one dependency is met
	if #self.deps > 0 and self:cfgvalue(section) then
		local stat = false

		for k, v in ipairs(self.deps) do
			if self:cfgvalue(section)[v.option] == v.value then
				stat = true
			end
		end

		if not stat then
			return nil
		end
	end

	return self:validate(section)
end


-- Dummy validate function
function TypedSection.validate(self, section)
	return section
end


--[[
AbstractValue - An abstract Value Type
	null:		Value can be empty
	valid:		A function returning the value if it is valid otherwise nil
	depends:	A table of option => value pairs of which one must be true
	default:	The default value
	size:		The size of the input fields
	rmempty:	Unset value if empty
	optional:	This value is optional (see AbstractSection.optionals)
]]--
AbstractValue = class(Node)

function AbstractValue.__init__(self, map, option, ...)
	Node.__init__(self, ...)
	self.option = option
	self.map    = map
	self.config = map.config
	self.tag_invalid = {}
	self.deps = {}

	self.rmempty  = false
	self.default  = nil
	self.size     = nil
	self.optional = false
end

-- Add a dependencie to another section field
function AbstractValue.depends(self, field, value)
	table.insert(self.deps, {field=field, value=value})
end

-- Return whether this object should be created
function AbstractValue.formcreated(self, section)
	local key = "cbi.opt."..self.config.."."..section
	return (luci.http.formvalue(key) == self.option)
end

-- Returns the formvalue for this object
function AbstractValue.formvalue(self, section)
	local key = "cbid."..self.map.config.."."..section.."."..self.option
	return luci.http.formvalue(key)
end

function AbstractValue.parse(self, section)
	local fvalue = self:formvalue(section)

	if fvalue and fvalue ~= "" then -- If we have a form value, write it to UCI
		fvalue = self:validate(fvalue)
		if not fvalue then
			self.tag_invalid[section] = true
		end
		if fvalue and not (fvalue == self:cfgvalue(section)) then
			self:write(section, fvalue)
		end
	else							-- Unset the UCI or error
		if self.rmempty or self.optional then
			self:remove(section)
		end
	end
end

-- Render if this value exists or if it is mandatory
function AbstractValue.render(self, s, scope)
	if not self.optional or self:cfgvalue(s) or self:formcreated(s) then
		scope = scope or {}
		scope.section = s
		scope.cbid    = "cbid." .. self.config ..
		                "."     .. s           ..
						"."     .. self.option

		scope.ifattr = function(cond,key,val)
			if cond then
				return string.format(
					' %s="%s"', tostring(key),
					tostring( val or scope[key] or self[key] or "" )
				)
			else
				return ''
			end
		end

		scope.attr = function(...)
			return scope.ifattr( true, ... )
		end

		Node.render(self, scope)
	end
end

-- Return the UCI value of this object
function AbstractValue.cfgvalue(self, section)
	return self.map:get(section, self.option)
end

-- Validate the form value
function AbstractValue.validate(self, value)
	return value
end

-- Write to UCI
function AbstractValue.write(self, section, value)
	return self.map:set(section, self.option, value)
end

-- Remove from UCI
function AbstractValue.remove(self, section)
	return self.map:del(section, self.option)
end




--[[
Value - A one-line value
	maxlength:	The maximum length
]]--
Value = class(AbstractValue)

function Value.__init__(self, ...)
	AbstractValue.__init__(self, ...)
	self.template  = "cbi/value"

	self.maxlength  = nil
end

-- This validation is a bit more complex
function Value.validate(self, val)
	if self.maxlength and tostring(val):len() > self.maxlength then
		val = nil
	end

	return val
end


-- DummyValue - This does nothing except being there
DummyValue = class(AbstractValue)

function DummyValue.__init__(self, map, ...)
	AbstractValue.__init__(self, map, ...)
	self.template = "cbi/dvalue"
	self.value = nil
end

function DummyValue.parse(self)

end

function DummyValue.render(self, s)
	luci.template.render(self.template, {self=self, section=s})
end


--[[
Flag - A flag being enabled or disabled
]]--
Flag = class(AbstractValue)

function Flag.__init__(self, ...)
	AbstractValue.__init__(self, ...)
	self.template  = "cbi/fvalue"

	self.enabled = "1"
	self.disabled = "0"
end

-- A flag can only have two states: set or unset
function Flag.parse(self, section)
	local fvalue = self:formvalue(section)

	if fvalue then
		fvalue = self.enabled
	else
		fvalue = self.disabled
	end

	if fvalue == self.enabled or (not self.optional and not self.rmempty) then
		if not(fvalue == self:cfgvalue(section)) then
			self:write(section, fvalue)
		end
	else
		self:remove(section)
	end
end



--[[
ListValue - A one-line value predefined in a list
	widget: The widget that will be used (select, radio)
]]--
ListValue = class(AbstractValue)

function ListValue.__init__(self, ...)
	AbstractValue.__init__(self, ...)
	self.template  = "cbi/lvalue"
	self.keylist = {}
	self.vallist = {}

	self.size   = 1
	self.widget = "select"
end

function ListValue.value(self, key, val)
	val = val or key
	table.insert(self.keylist, tostring(key))
	table.insert(self.vallist, tostring(val))
end

function ListValue.validate(self, val)
	if luci.util.contains(self.keylist, val) then
		return val
	else
		return nil
	end
end



--[[
MultiValue - Multiple delimited values
	widget: The widget that will be used (select, checkbox)
	delimiter: The delimiter that will separate the values (default: " ")
]]--
MultiValue = class(AbstractValue)

function MultiValue.__init__(self, ...)
	AbstractValue.__init__(self, ...)
	self.template = "cbi/mvalue"
	self.keylist = {}
	self.vallist = {}

	self.widget = "checkbox"
	self.delimiter = " "
end

function MultiValue.render(self, ...)
	if self.widget == "select" and not self.size then
		self.size = #self.vallist
	end

	AbstractValue.render(self, ...)
end

function MultiValue.value(self, key, val)
	val = val or key
	table.insert(self.keylist, tostring(key))
	table.insert(self.vallist, tostring(val))
end

function MultiValue.valuelist(self, section)
	local val = self:cfgvalue(section)

	if not(type(val) == "string") then
		return {}
	end

	return luci.util.split(val, self.delimiter)
end

function MultiValue.validate(self, val)
	val = (type(val) == "table") and val or {val}

	local result

	for i, value in ipairs(val) do
		if luci.util.contains(self.keylist, value) then
			result = result and (result .. self.delimiter .. value) or value
		end
	end

	return result
end