--------------------------------------------------------------------------------
-- Title:               IPLocation.lua
-- Description:         Like a square peg in a round hole
-- Author:              Raphaël Szwarc http://alt.textdrive.com/lua/
-- Creation Date:       July 9, 2008
-- Legal:               Copyright (C) 2007 Raphaël Szwarc
--                      Under the terms of the MIT License
--                      http://www.opensource.org/licenses/mit-license.html
--------------------------------------------------------------------------------

-- import dependencies
local io = require( 'io' )

local assert = assert
local error = error
local getmetatable = getmetatable
local ipairs = ipairs
local loadstring = loadstring
local pcall = pcall
local require = require
local setmetatable = setmetatable
local tonumber = tonumber
local tostring = tostring

--------------------------------------------------------------------------------
-- IPLocation
--------------------------------------------------------------------------------

module( 'IPLocation' )
_VERSION = '1.0'

local self = setmetatable( _M, {} )
local meta = getmetatable( self )

--------------------------------------------------------------------------------
-- DDL
--------------------------------------------------------------------------------

local function Path( anExtension )
    return ( '%s%s.%s' ):format( require( 'Bundle' )(), self._NAME, anExtension )
end

local function Load( anExtension )
    local aPath = Path( anExtension )
    local aFile = assert( io.open( aPath, 'rb' ) )
    local aContent = assert( aFile:read( '*a' ) )
    local aContent = ( 'return { %s }' ):format( aContent )
    local aChunk = assert( loadstring( aContent ) )
    local aStatement = assert( aChunk() )
    
    aFile:close()
    
    return aStatement
end

local DDL = Load( 'ddl' )
local DML = Load( 'dml' )

--------------------------------------------------------------------------------
-- DB
--------------------------------------------------------------------------------

local function NewDB( aURL )
    local aCall = function()
        local DB = require( 'DB' )
        local aDB = DB( aURL )
         
        for anIndex, aStatement in ipairs( DDL ) do
            aDB( aStatement )
        end 
    
        return aDB
    end
    local ok, aDB = pcall( aCall )
    
    if ok then
        return aDB
    end
end

local function IPNumber( anAddress )
    local anAddress = anAddress or ''
    local first, second, third, fourth = anAddress:match( '(%d+)%.(%d+)%.(%d+)%.(%d+)' )
    
    if first and second and third and fourth then
        local aNumber = 0

        aNumber = aNumber + tonumber( first ) * 16777216 
        aNumber = aNumber + tonumber( second ) * 65536 
        aNumber = aNumber + tonumber( third ) * 256
        aNumber = aNumber + tonumber( fourth )

        return aNumber
    end
    
    return 0    
end

local function FindLocation( aDB, anAddress )
    if aDB then
        local aCall = function()
            local aNumber = IPNumber( anAddress )
            local aCursor = aDB( DML[ 'FindLocation' ], aNumber )
            local aRow = aCursor()
            
            aCursor.close = true
            
            if aRow and aNumber >= tonumber( aRow[ 'start' ] ) and aNumber <= tonumber( aRow[ 'end' ] ) then
                return aRow
            end 
        end
        local ok, aResult = pcall( aCall )
        
        if ok then
            return aResult
        end
    end
end

--------------------------------------------------------------------------------
-- Metamethods
--------------------------------------------------------------------------------

local db = NewDB( 'sqlite3://localhost/' .. Path( 'db' ) )

function meta:__call( anAddress )
    return IPNumber( anAddress )
end

function meta:__index( aKey )
    return FindLocation( db, aKey )
end

function meta:__concat( aValue )
    return tostring( self ) .. tostring( aValue )
end

function meta:__tostring()
    return ( '%s/%s' ):format( self._NAME, self._VERSION )
end