--------------------------------------------------------------------------------
--  Copyright (c) 2012 Sierra Wireless.
--  All rights reserved. This program and the accompanying materials
--  are made available under the terms of the Eclipse Public License v1.0
--  which accompanies this distribution, and is available at
--  http://www.eclipse.org/legal/epl-v10.html
--
--  Contributors:
--       Kevin KIN-FOO <kkinfoo@sierrawireless.com>
--           - initial API and implementation and initial documentation
--------------------------------------------------------------------------------
local apimodel = require 'models.apimodel'

---
-- @module docutils
-- Handles link generation, node quick description.
--
-- Provides:
--  * link generation
--  * anchor generation
--  * node quick description
local M = {}

function M.isempty(map)
  local f = pairs(map)
  return f(map) == nil
end

---
-- Provide a handling function for all supported anchor types
--                    recordtypedef => #(typename)
--    item (field of recordtypedef) => #(typename).itemname
--                    item (global) => itemname
--functiontypedef callof given type => ##(giventypename)__call

M.anchortypes = {
  recordtypedef = function (o) return string.format('#(%s)', o.name) end,
  functiontypedef = function (o,t) return string.format('#(%s)__call', t.name) end,
  item = function(o)
    if not o.parent or o.parent.tag == 'file' then
      -- Handle items referencing globals
      return o.name
    elseif o.parent and o.parent.tag == 'recordtypedef' then
      -- Handle items included in recordtypedef
      local recordtypedef = o.parent
      local recordtypedefanchor = M.anchor(recordtypedef)
      if not recordtypedefanchor then
        return nil, 'Unable to generate anchor for `recordtypedef parent.'
      end
      return string.format('%s.%s', recordtypedefanchor, o.name)
    end
    return nil, 'Unable to generate anchor for `item'
  end
}

---
-- Provides anchor string for an object of API mode
--
-- @function [parent = #docutils] anchor
-- @param modelobject Object form API model
-- @result #string Anchor for an API model object, this function __may rise an error__
-- @usage # -- In a template
-- # local anchorname = anchor(someobject)
-- <a id="$(anchorname)" />
function M.anchor( modelobject,... )
  local tag = modelobject.tag
  if M.anchortypes[ tag ] then
    return M.anchortypes[ tag ](modelobject,...)
  end
  return nil, string.format('No anchor available for `%s', tag)
end

local function getexternalmodule( item )
  -- Get file which contains this item
  local file
  if item.parent then
    if item.parent.tag =='recordtypedef' then
      local recordtypedefparent = item.parent.parent
      if recordtypedefparent and recordtypedefparent.tag =='file'then
        file = recordtypedefparent
      end
    elseif item.parent.tag =='file' then
      file = item.parent
    else
      return nil, 'Unable to fetch item parent'
    end
  end
  return file
end

---
-- Provide a handling function for all supported link types
--
--                        internaltyperef => ##(typename)
--                                        => #anchor(recordtyperef)
--                        externaltyperef => modulename.html##(typename)
--                                        => linkto(file)#anchor(recordtyperef)
--                           file(module) => modulename.html
--                                  index => index.html
--      functiontypedef callof given type => ##(giventypename)__call
--                          recordtypedef => ##(typename)
--                                        => #anchor(recordtyperef)
-- item (internal field of recordtypedef) => ##(typename).itemname
--                                        => #anchor(item)
--                 item (internal global) => #itemname
--                                        => #anchor(item)
-- item (external field of recordtypedef) => modulename.html##(typename).itemname
--                                        => linkto(file)#anchor(item)
--                  item (externalglobal) => modulename.html#itemname
--                                        => linkto(file)#anchor(item)
M.linktypes = {
  internaltyperef  = function(o) return string.format('##(%s)', o.typename) end,
  externaltyperef  = function(o) return string.format('%s.html##(%s)', o.modulename, o.typename) end,
  file            = function(o) return string.format('%s.html', o.name) end,
  index           = function() return 'index.html' end,
  recordtypedef   = function(o)
    local anchor = M.anchor(o)
    if not anchor then
      return nil, 'Unable to generate anchor for `recordtypedef.'
    end
    return string.format('#%s', anchor)
  end,
  functiontypedef   = function(o,...)
    local anchor = M.anchor(o,...)
    if not anchor then
      return nil, 'Unable to generate anchor for `functiontypedef.'
    end
    return string.format('#%s', anchor)
  end,
  item = function(o)

    -- For every item get anchor
    local anchor = M.anchor(o)
    if not anchor then
      return nil, 'Unable to generate anchor for `item.'
    end

    -- Built local link to item
    local linktoitem = string.format('#%s', anchor)

    --
    -- For external item, prefix with the link to the module.
    --
    -- The "external item" concept is used only here for short/embedded
    -- notation purposed. This concept and the `.external` field SHALL NOT
    -- be used elsewhere.
    --
    if o.external then

      -- Get link to file which contains this item
      local file = getexternalmodule( o )
      local linktofile = file and M.linkto( file )
      if not linktofile then
        return nil, 'Unable to generate link for external `item.'
      end

      -- Built external link to item
      linktoitem = string.format("%s%s", linktofile, linktoitem)
    end

    return linktoitem
  end
}

---
-- Generates text for HTML links from API model element
--
-- @function [parent = #docutils]
-- @param modelobject Object form API model
-- @result #string Links text for an API model element, this function __may rise an error__.
-- @usage # -- In a template
-- <a href="$( linkto(api) )">Some text</a>
function M.linkto( apiobject,...)
  local tag = apiobject.tag
  if M.linktypes[ tag ] then
    return M.linktypes[tag](apiobject,...)
  end
  if not tag then
    return nil, 'Link generation is impossible as no tag has been provided.'
  end
  return nil, string.format('No link generation available for `%s.', tag)
end

---
-- Provide a handling function for all supported pretty name types
--                                 primitivetyperef => #typename
--                                  internaltyperef => #typename
--                                  inlinetyperef   => #def.typename
--                                  externaltyperef => modulename#typename
--                                     file(module) => modulename
--                                            index => index
--                functiontypedef callof given type => giventypename(param1,param2, ...)
--                                    recordtypedef => typename
--        item (internal function of recordtypedef) => typename.itemname(param1, param2,...)
--  item (internal func with self of recordtypedef) => typename:itemname(param2)
--  item (internal non func field of recordtypedef) => typename.itemname
--                      item (internal func global) => functionname(param1, param2,...)
--                  item (internal non func global) => itemname
--        item (external function of recordtypedef) => modulename#typename.itemname(param1, param2,...)
--  item (external func with self of recordtypedef) => modulename#typename:itemname(param2)
--  item (external non func field of recordtypedef) => modulename#typename.itemname
--                      item (external func global) => functionname(param1, param2,...)
--                  item (external non func global) => itemname
M.prettynametypes = {
  primitivetyperef = function(o) return string.format('#%s', o.typename) end,
  externaltyperef = function(o) return string.format('%s#%s', o.modulename, o.typename) end,
  inlinetyperef = function(o)
    if not(o.def and o.def.tag == "recordtypedef" and o.def.name) then
      return nil
    end
    if o.def.name == "list" then
      local valuetypename = M.prettyname(o.def.defaultvaluetyperef)
      return valuetypename and string.format('#list&lt;%s&gt;', valuetypename) or nil
    elseif o.def.name == "map" then
      local keytypename = M.prettyname(o.def.defaultkeytyperef)
      local valuetypename = M.prettyname(o.def.defaultvaluetyperef)
      return keytypename and valuetypename and string.format('#map&lt;%s,%s&gt;', keytypename, valuetypename) or nil
    else
      return string.format('#%s',o.def.name)
    end
  end,
  index = function(o) return "index" end,
  file = function(o) return o.name end,
  recordtypedef = function(o) return o.name end,
  functiontypedef = function(o,t)
    if t and t.tag == 'recordtypedef' and t.name then
      local paramlist = {}
      for position, param in ipairs(o.params) do
        -- we ignore the first param
        if not (position == 1) then
          table.insert(paramlist, param.name)
        end
      end
      return string.format('%s(%s)',t.name, table.concat(paramlist, ", "))
    end
  end,
  item = function( o )

    -- Determine item name
    -- ----------------------
    local itemname = o.name

    -- Determine scope
    -- ----------------------
    local parent = o.parent
    local isglobal = parent and parent.tag == 'file'
    local isfield = parent and parent.tag == 'recordtypedef'

    -- Determine type name
    -- ----------------------

    local typename = isfield and parent.name

    -- Fetch item definition
    -- ----------------------
    -- Get file object
    local file
    if isglobal then
      file = parent
    elseif isfield then
      file = parent.parent
    end
    -- Get definition
    local definition = o:resolvetype (file)


    -- Build prettyname
    -- ----------------------
    local prettyname
    if not definition or definition.tag ~= 'functiontypedef' then
      -- Fields
      if isglobal or not typename then
        prettyname = itemname
      else
        prettyname = string.format('%s.%s', typename, itemname)
      end
    else
      -- Functions
      -- Build parameter list
      local paramlist = {}
      local isinvokable = M.isinvokable(o)
      for position, param in ipairs(definition.params) do
        -- For non global function, when first parameter is 'self',
        -- it will not be part of listed parameters
        if not (position == 1 and isinvokable and isfield) then
          table.insert(paramlist, param.name)
          if position ~= #definition.params then
            table.insert(paramlist, ', ')
          end
        end
      end

      if isglobal or not typename then
        prettyname = string.format('%s(%s)',itemname, table.concat(paramlist))
      else
        -- Determine function prefix operator,
        -- ':' if 'self' is first parameter, '.' else way
        local operator = isinvokable and ':' or '.'

        -- Append function parameters
        prettyname = string.format('%s%s%s(%s)',typename, operator, itemname, table.concat(paramlist))
      end
    end

    -- Manage external Item prettyname
    -- ----------------------
    local externalmodule = o.external and getexternalmodule( o )
    local externalmodulename = externalmodule and externalmodule.name

    if externalmodulename then
      return string.format('%s#%s',externalmodulename,prettyname)
    else
      return prettyname
    end
  end
}
M.prettynametypes.internaltyperef = M.prettynametypes.primitivetyperef

---
-- Check if the given item is a function that can be invoked
function M.isinvokable(item)
  --test if the item is global
  if item.parent and item.parent.tag == 'file' then
    return false
  end
  -- check first param
  local definition = item:resolvetype()
  if definition and definition.tag == 'functiontypedef' then
    if (#definition.params > 0) then
      return definition.params[1].name == 'self'
    end
  end
end

---
-- Provide human readable overview from an API model element
--
-- Resolve all element needed to summurize nicely an element form API model.
-- @usage $ print( prettyname(item) )
--  module:somefunction(secondparameter)
-- @function [parent = #docutils]
-- @param apiobject Object form API model
-- @result #string Human readable description of given element.
-- @result #nil, #string In case of error.
function M.prettyname( apiobject, ... )
  local tag = apiobject.tag
  if M.prettynametypes[tag] then
    return M.prettynametypes[tag](apiobject,...)
  elseif not tag then
    return nil, 'No pretty name available as no tag has been provided.'
  end
  return nil, string.format('No pretty name for `%s.', tag)
end

---
-- Just make a string print table in HTML.
-- @function [parent = #docutils] securechevrons
-- @param #string String to convert.
-- @usage securechevrons('<markup>') => '&lt;markup&gt;'
-- @return #string Converted string.
function M.securechevrons( str )
  if not str then return nil, 'String expected.' end
  return string.gsub(str:gsub('<', '&lt;'), '>', '&gt;')
end

-------------------------------------------------------------------------------
-- Handling format of @{some#type} tag.
-- Following functions enable to recognize several type of references between
-- "{}".
-------------------------------------------------------------------------------

---
-- Build a global var from string such as:
-- * `global#foo`
-- * `foo#global.bar`
-- @param #string str
local globals = function(str)
  -- Handling globals from modules
  local modulename, fieldname = str:gmatch('([%a%.%d_]+)#global%.([%a%.%d_]+)')()
  if modulename and fieldname then
    local item = apimodel._item(fieldname)
    local file = apimodel._file()
    file.name = modulename
    file:addglobalvar( item )
    return item
  end
  -- Handling other globals
  local name =  str:gmatch('global#([%a%.%d_]+)')()
  if name then
    return apimodel._externaltypref('global', name)
  end
  return nil
end

---
-- Build an external field from string like `module#(type).field`
-- @param #string str
local field = function( str )

  -- Match `module#type.field`
  local mod, typename, fieldname = str:gmatch('([%a%.%d_]*)#([%a%.%d_]+)%.([%a%.%d_]+)')()

  -- Try matching `module#(type).field`
  if not mod then
    mod, typename, fieldname = str:gmatch('([%a%.%d_]*)#%(([%a%.%d_]+)%)%.([%a%.%d_]+)')()
    if not mod then
      -- No match
      return nil
    end
  end

  -- Build according `item
  local modulefielditem = apimodel._item( fieldname )
  local moduletype = apimodel._recordtypedef(typename)
  moduletype:addfield( modulefielditem )
  local typeref
  if #mod > 0 then
    local modulefile = apimodel._file()
    modulefile.name = mod
    modulefile:addtype( moduletype )
    typeref = apimodel._externaltypref(mod, typename)
    modulefielditem.external = true
  else
    typeref = apimodel._internaltyperef(typename)
  end
  modulefielditem.type = typeref
  return modulefielditem
end

---
-- Build an API internal reference from a string like: `#typeref` or #(type.ref)
-- @param #string str
local internal = function ( str )
  local typename = str:gmatch('#([%a%.%d_]+)')()
  if not typename then
    typename = str:gmatch('#%(([%a%.%d_]+)%)')()
    if not typename then
      -- No match
      return nil
    end
  end

  -- Do not handle this name is it starts with reserved name "global"
  if typename:find("global.") == 1 then return nil end
  return apimodel._internaltyperef(typename)
end

---
-- Build an API external reference from a string like: `mod.ule#type`
-- @param #string str
local extern = function (str)

  -- Match `mod.ule#ty.pe`
  local modulename, typename = str:gmatch('([%a%.%d_]+)#([%a%.%d_]+)')()

  -- Trying  `mod.ule#(ty.pe)`
  if not modulename then
    modulename, typename = str:gmatch('([%a%.%d_]+)#%(([%a%.%d_]+)%)')()

    -- No match at all
    if not modulename then
      return nil
    end
  end
  return apimodel._externaltypref(modulename, typename)
end

---
-- Build an API module(file) from a string like: `mod.ule`
-- @param #string str
local file = function (str)
  local modulename = str:gmatch('([%a%.%d_]+)')()
  if modulename then
    local file = apimodel._file()
    file.name = modulename
    return file
  end
  return nil
end


---
-- Provide API Model element from a string
-- @usage local externaltyperef = getelement("somemodule#somefield")
function M.getelement( str )

  -- Order matters, more restrictive are at begin of table
  local extractors = {
    globals,
    field,
    extern,
    internal,
    file
  }
  -- Loop over extractors.
  -- First valid result is used
  for _, extractor in ipairs( extractors ) do
    local result = extractor( str )
    if result then return result end
  end
  return nil
end

--------------------------------------------------------------------------------
-- Iterator that iterates on the table in key ascending order.
--
-- @function [parent=#utils.table] sortedPairs
-- @param t table to iterate.
-- @return iterator function.
function M.sortedpairs(t)
  local a = {}
  local insert = table.insert
  for n in pairs(t) do insert(a, n) end
  table.sort(a)
  local i = 0
  return function()
    i = i + 1
    return a[i], t[a[i]]
  end
end
return M