--[[
    tutel host

                    __
         .,-;-;-,. /'_\
       _/_/_/_|_\_\) /
     '-<_><_><_><_>=/\
       `/_/====/_/-'\_\
        ""     ""    ""
]]

--[[
    network variables
]]
local HOST_CHANNEL = 1337
local TURTLE_CHANNEL_BASE = 1338

local MSG_HEADER = 0x747574656C

local modem = peripheral.find("modem") or error("No modems found", 0)
modem.open(HOST_CHANNEL)

--[[
    logging
]]
local logTypes = {
    ["general"] = {
        ["BG"] = colours.green,
        ["FG"] = colours.white
    },

    ["info"] = {
        ["BG"] = colours.blue,
        ["FG"] = colours.white
    },

    ["warning"] = {
        ["BG"] = colours.orange,
        ["FG"] = colours.black,
        ["AffectContent"] = true
    },

    ["error"] = {
        ["BG"] = colours.red,
        ["FG"] = colours.black,
        ["AffectContent"] = true
    }
}
local log = {}

for typeName, format in pairs(logTypes) do
    log[typeName] = function(fmt, ...)
        local prevColourBg = term.getBackgroundColour()
        local prevColourFg = term.getTextColour()

        term.setBackgroundColour(format["BG"])
        term.setTextColour(format["FG"])
        io.write(("[%s @ line %d]"):format(typeName, debug.getinfo(2, "l").currentline))

        if format["AffectContent"] then
            io.write(" ", string.format(fmt, ...), "\n")
            term.setBackgroundColour(prevColourBg)
            term.setTextColour(prevColourFg)
        else
            term.setBackgroundColour(prevColourBg)
            term.setTextColour(prevColourFg)
            io.write(" ", string.format(fmt, ...), "\n")
        end
    end
end

--[[
    turtle tracking
]]
local turtles = {}

function registerTurtle(pos, fuel, id)
    local channel = TURTLE_CHANNEL_BASE + #turtles

    local turt = {
        ["channel"] = channel,
        ["index"] = #turtles,
        ["position"] = pos,
        ["fuel"] = fuel,
        ["status"] = "IDLE",
        ["id"] = id
    }

    table.insert(turtles, turt)

    return turt
end

--[[
    helper networking functions
]]
function sendToAll(name, msgData)
    local message = {
        ["header"] = MSG_HEADER,
        ["name"] = name,
        ["data"] = msgData or {}
    }

    modem.transmit(0, 0, message)
end

--[[
    event handling
]]
local eventListeners = {}
local function registerEventListener(name, listener)
    if not eventListeners[name] then eventListeners[name] = {} end
    table.insert(eventListeners[name], listener)
end

local function dispatchEvents(event, ...)
    log.info("dispatching event: %s", event)

    local eventTbl = eventListeners[event]

    if not eventTbl then return end

    for i = 0, #eventTbl, 1 do
        eventTbl[i](...)
    end
end

--[[
    command handling
]]
local commands = {}
function declareCommandHandler(name, handler, requiredKeys)
    commands[name] = {
        ["keys"] = requiredKeys or {},
        ["handler"] = handler
    }
end

-- scan
function handleScan(keys, id)
    local turt = registerTurtle({ keys.positionX, keys.positionY, keys.positionZ }, keys.fuel, id)

    log.info("Received turtle info (pos: %d, %d, %d - fuel: %d - channel: %d - id: %d)", turt.position[1],
        turt.position[2], turt.position[3], turt.fuel, turt.channel, id)

    sendToAll("REGISTER", { ["id"] = id, ["turtleChannel"] = turt.channel })
end

declareCommandHandler("SCAN", handleScan,
    {
        ["positionX"] = "number",
        ["positionY"] = "number",
        ["positionZ"] = "number",
        ["fuel"] = "number"
    })


--[[
    modem message handler
]]
local function handleMessages(side, channel, replyChannel, message, dist)
    if channel ~= HOST_CHANNEL then return end

    -- msg validation
    if type(message) ~= "table" then return end
    if not message.header or message.header ~= MSG_HEADER then return end
    if not message.data then message.data = {} end

    -- cmd validation
    if not message.name then
        log.warning("received nameless command?")
        return
    end

    if not commands[message.name] then
        log.error("unhandled command (%s)", message.name)
        return
    end

    local cmd = commands[message.name]
    for i, v in pairs(cmd.keys) do
        if type(message.data[i]) ~= v and v ~= "optional" then
            log.error("command %s requires key %s of type %s (was %s)", message.name, i, v, type(message[i]))
            return
        end
    end

    -- cmd execution
    local success, err = pcall(cmd.handler, message.data, message.id)
    if not success then
        log.error("error occurred while executing command %s: %s", message.name, err)
    end
end
registerEventListener("modem_message", handleMessages)

--[[
    main
]]
log.general("tutel host init")

-- transmit scan
log.info("broadcasting SCAN")
sendToAll("SCAN", { ["hostChannel"] = HOST_CHANNEL })

--[[
    loop functions
]]
function updateScreen()
    local w, h = term.getSize()

    local function drawTextCentered(text)
        local x = (w / 2) - (text:len() / 2)
        local _, curY = term.getCursorPos()
        term.setCursorPos(x, curY)
        term.write(text)
    end

    term.setBackgroundColor(colors.black)
    term.clear()
    term.setCursorPos(1, 1)

    term.setBackgroundColor(colors.lightGray)
    term.setTextColour(colors.black)
    term.clearLine()
    drawTextCentered("tutel host controller")
end

function pollEvents()
    local eventData = { os.pullEvent() }

    local eventName = eventData[1]
    table.remove(eventData, 1)

    dispatchEvents(eventName, table.unpack(eventData))
end

while true do
    pollEvents()
end