local getopt = require('getopt')
local utils = require('utils')

example = "script calculates many different checksums (CRC) over the provided hex input"
author = "Iceman"
desc =
[[
This script calculates many checksums (CRC) over the provided hex input.

Arguments:
    -b              data in hex
    -w              bitwidth of the CRC family of algorithm. <optional> defaults to all known CRC presets.
Examples :
    script run e -b 010203040506070809
    script run e -b 010203040506070809 -w 16
]]

---
-- A debug printout-function
function dbg(args)
    if DEBUG then
        print("###", args)
    end
end
---
-- This is only meant to be used when errors occur
function oops(err)
    print("[!] ERROR: ",err)
    return nil,err
end
---
-- Usage help
function help()
    print(desc)
    print("Example usage")
    print(example)
end
---
-- The main entry point
function main(args)

    local data
    local width = 0

    -- Read the parameters
    for o, a in getopt.getopt(args, 'hb:w:') do
        if o == "h" then return help() end
        if o == "b" then data = a end
        if o == "w" then width = a end
    end

    data = data or '01020304'
    width = width or 0

    print( string.rep('-',60) )
    print('Bit width of CRC | '..width)
    print('Bytes            | '..data)
    print('')
    print( ('%-20s| %-16s| %s'):format('Model','CRC', 'CRC reverse','bigEnd', 'bigEnd','little','little'))
    print( string.rep('-',60) )
    local lists, err = core.reveng_models(width)
    if lists == nil then return oops(err) end

    for _,i in pairs(lists) do
        if string.len(i) > 1 then
            local a1 = core.reveng_runmodel(i, data, false, '0')
            local a2 = core.reveng_runmodel(i, data, true, '0')
            local a3 = core.reveng_runmodel(i, data, false, 'b')
            local a4 = core.reveng_runmodel(i, data, false, 'B')
            local a5 = core.reveng_runmodel(i, data, false, 'l')
            local a6 = core.reveng_runmodel(i, data, false, 'L')
            print( ('%-20s| %-16s| %-16s| %-16s| %-16s| %-16s| %-16s'):format(i, a1:upper(), a2:upper(),a3:upper(),a4:upper(),a5:upper(),a6:upper() ) )
        end
    end
end

main(args)