#!/usr/bin/env lua

local socket = require 'socket'
local http = require 'socket.http'
local url = require 'socket.url'
local math = require 'math'

local username = 'doyster'
local pass_hash = '63ff9c4d9cf5d1a68a63deeb74b034ef'

function md5(str)
    local file = io.popen('echo -n ' .. str .. ' | md5sum', 'r')
    local ret = file:read()
    file:close()
    ret = string.sub(ret, 1, 32)
    return ret
end

function handshake(username)
    local handshake_url = 'http://post.audioscrobbler.com/?hs=true&p=1.1&c=tst&v=1.0&u=' .. username

    print("Sending handshake request to " .. handshake_url)
    response = http.request(handshake_url)
    print("Response to handshake:\n" .. response)
    local i = 1
    local response_lines = {}
    for line in string.gfind(response, "[^\n]+") do
        response_lines[i] = line
        i = i + 1
    end
    if i ~= 5 or string.sub(response_lines[1], 1, 2) ~= 'UP' then
        return nil, "Error in handshake!"
    end

    return response_lines
end

function parse_cache(cache_text)
    local tracks = {}
    for track in string.gfind(cache_text, "a%[%d+%]=[^&]*&t%[%d+%]=[^&]*&b%[%d+%]=[^&]*&l%[%d+%]=[^&]*&i%[%d+%]=[^&]*&m%[%d+%]=[^&]*&") do
        local _, _, artist, track, album, length, time, mbid = string.find(track, "a%[%d+%]=([^&]*)&t%[%d+%]=([^&]*)&b%[%d+%]=([^&]*)&l%[%d+%]=([^&]*)&i%[%d+%]=([^&]*)&m%[%d+%]=([^&]*)&")
        table.insert(tracks, {artist = artist,
                              track = track,
                              album = album, 
                              length = length,
                              time = time,
                              mbid = mbid})
    end
    return tracks
end

function submit(username, challenge_response, submit_url, tracks)
    local to_submit = ""
    for i, track in ipairs(tracks) do
        to_submit = to_submit .. string.format("a[%d]=%s&t[%d]=%s&b[%d]=%s&l[%d]=%s&i[%d]=%s&m[%d]=%s&", i - 1, track.artist, i - 1, track.track, i - 1, track.album, i - 1, track.length, i - 1, track.time, i - 1, track.mbid)
    end

    submission = 'u=' .. username .. '&s=' .. challenge_response .. '&' .. to_submit
    print('Submitting ' .. submission .. ' to ' .. submit_url)
    response = http.request(submit_url, url.unescape(submission))
    print("Response to submission:\n" .. response)
end

local handshake_response = assert(handshake(username))

local challenge_response = md5(pass_hash .. handshake_response[2])

local file = io.open(arg[1], 'r')
local raw_tracks = file:read()
file:close()

local tracks = parse_cache(raw_tracks)

local to_submit = {}
for i = 0, math.floor(table.getn(tracks) / 10) - 1 do
    for j = 1, 10 do
        to_submit[j] = tracks[j+10*i]
    end
    submit(username, challenge_response, handshake_response[3], to_submit)
    to_submit = {}
    print("Sleeping...")
    socket.sleep(2)
end
for j = 1, math.mod(table.getn(tracks), 10) do
    to_submit[j] = tracks[j+10*math.floor(table.getn(tracks) / 10)]
end
submit(username, challenge_response, handshake_response[3], to_submit)