-- pchat by hugeblank, Feb 2023
-- Requires computer have a wireless modem, 
-- and be licensed with a chatbox.
-- Usage:
-- ^pcjoin <channel [1-65535]> <passkey> - Join a channel.
-- ^pchat <message> - Send a message to joined channel.
-- ^pclist - List current users in joined channel.
-- ^pcleave - Disconnect from joined channel.
-- All command names can be modified, see commandNames table. Ex, changing ^pchat to ^p
sleep(0.5)
local aes = require("aes")
local sha = require("sha")
local aliases = require("aliases")
assert(chatbox, "Missing a chatbox! Run `/chatbox license` in chat to get started.")

local modem
do
    local modems = {peripheral.find("modem")}
    local i = 1
    while i <= #modems and not modem do
        if modems[i].isWireless() then
            modem = modems[i]
        end
        i = i+1
    end
    if not modem then
        printError("Wireless Modem not found")
    end
end

local owner = chatbox.getLicenseOwner()
local commands = {}
local key, channel
local users = {}

local function packet(type, message)
    local data = {
        type = type,
        message = message,
    }
    local encData = aes.encrypt_str(textutils.serialise(data), key)
    modem.transmit(channel, channel, encData)
end

local function unpacket(encData)
    local data
    local ok = pcall(function() 
        data = textutils.unserialise(aes.decrypt_str(encData, key))
    end)
    if ok then
        return data.type, data.message
    end
end

local function printError(...)
    chatbox.tell(owner, "&c"..table.concat(table.pack(...), " "), "pchat", nil, "format")
end

local function print(...)
    chatbox.tell(owner, table.concat(table.pack(...), " "), "pchat")
end

local function status(...)
    chatbox.tell(owner, "&e"..table.concat(table.pack(...), " "), "pchat", nil, "format")
end

local function isJoined()
    if not key then
        printError("Not joined to any channel!")
        return false
    end
    return true
end

-- pchat
commands[aliases.pchat] = function(args)
    if isJoined() then
        local msg = table.concat(args, " ")
        packet("message", {
            user = owner,
            message = msg
        })
        print("<"..owner.."> "..msg)
    end
end

-- pcleave
commands[aliases.pcleave] = function(args)
    if isJoined() then
        packet("leave", owner)
        status("Left channel "..channel)
        key, channel = nil, nil
        users = {}
    end
end

-- pcjoin
commands[aliases.pcjoin] = function(args)
    local nchannel, nkey = tonumber(args[1]), args[2]
    if not nchannel then
        printError("Expected channel number, got "..(args[1] or "nil"))
        return
    elseif not nkey then
        printError("Missing passcode.")
        return
    end
    if key then
        packet("leave", owner)
        modem.close(channel)
        status("Switched channels from", channel, "to", nchannel, ".")
    else
        status("Joined channel "..nchannel)
    end
    key = aes.strToBlocks(sha.digestStr("000-PCHAT-"..nkey))[1]
    channel = nchannel
    users = {
        [owner] = true
    }
    modem.open(channel)
    packet("join", owner)
    packet("getList")
end

-- pclist
commands[aliases.pclist] = function()
    local out = {
        "Current users in channel:",
    }
    for user in pairs(users) do
        out[#out+1] = user
    end
    local str = table.concat(out, "\n"):gsub("&", "")
    print(str)
end

local args = {...}
if #args == 2 then
    commands[aliases.pcjoin](args)
else
    _G.print("PChat is now running! Usage:")
    _G.print("^pcjoin <channel> <passcode>")
    _G.print("^pcleave")
    _G.print("^pclist")
    _G.print("^pchat <message>")
end

while true do
    local e, user, command, args, data = os.pullEventRaw()
    if e == "command" then
        if data.ownerOnly and user == owner then
            for key, alias in pairs(aliases) do
                for i = 1, #alias do
                    if command == alias[i] then
                        commands[aliases[key]](args)
                        break
                    end
                end
            end
        elseif user == owner and commands[command] then
            printError("pchat command leaked! When using pchat commands *always* use ^ instead of \\!")
        end
    elseif e == "modem_message" then
        local m_type, message = unpacket(data)
        if m_type == "message" and type(message) == "table" and message.user and message.message then
            print("<"..tostring(message.user).."> "..tostring(message.message))
        elseif m_type == "join" and type(message) == "string" then
            status(message:gsub("&", "").." has joined the channel.")
            users[message] = true
        elseif m_type == "leave" and type(message) == "string" then
            status(message:gsub("&", "").." has left the channel.")
            users[message] = nil
        elseif m_type == "getList" then
            packet("list", owner)
        elseif m_type == "list" and type(message) == "string" then
            users[message] = true
        end
    end
end