--[[
  Wireless Keyboard - Sender
  Usage: wkey <channel>
  Default channel: 12345
]]

local args = {...}
local channel = tonumber(args[1]) or 12345

local modem = peripheral.find("modem") or peripheral.find("wireless_modem")
if not modem then
    print("ERROR: Wireless modem not found. Please attach one.")
    return
end

modem.open(channel)

term.clear()
term.setCursorPos(1, 1)
print("=== Wireless Keyboard - Sender ===")
print("Channel: " .. channel)
print("Status: Connected")
print("-----------------------------------")
print("Input: ")
print("-----------------------------------")
print("[Ctrl+T to quit]")

local input = ""
local cursorPos = 1
local inputLineY = 5 -- line where "Input: " is printed

local function updateInput()
    term.setCursorPos(1, inputLineY + 1)
    term.clearLine()
    term.write("> " .. input)
    -- clear extra spaces
    local spaces = 40 - #input
    if spaces > 0 then
        term.write(string.rep(" ", spaces))
    end
    -- set cursor position
    local cursorX = 3 + cursorPos  -- "> " is 2 chars, so cursor start at 3?
    -- Actually "> " length is 2, so cursorX = 2 + cursorPos + 1? Let's calculate:
    -- We write "> " then input, so the cursor should be after "> " + (cursorPos-1) chars.
    cursorX = 2 + cursorPos
    term.setCursorPos(cursorX, inputLineY + 1)
    term.setCursorBlink(true)
end

updateInput()

local function sendData(data)
    modem.transmit(channel, channel, data)
end

while true do
    local event, p1, p2 = os.pullEvent()
    
    if event == "char" then
        local char = p1
        input = input:sub(1, cursorPos - 1) .. char .. input:sub(cursorPos)
        cursorPos = cursorPos + 1
        sendData({ type = "char", data = char })
        updateInput()
        
    elseif event == "key" then
        local keyCode = p1
        local isHeld = p2
        
        if keyCode == keys.backspace then
            if cursorPos > 1 then
                input = input:sub(1, cursorPos - 2) .. input:sub(cursorPos)
                cursorPos = cursorPos - 1
                sendData({ type = "control", data = "backspace" })
                updateInput()
            end
            
        elseif keyCode == keys.enter then
            if #input > 0 then
                sendData({ type = "line", data = input })
            end
            sendData({ type = "control", data = "enter" })
            input = ""
            cursorPos = 1
            updateInput()
            
        elseif keyCode == keys.left then
            if cursorPos > 1 then
                cursorPos = cursorPos - 1
                updateInput()
            end
            
        elseif keyCode == keys.right then
            if cursorPos <= #input then
                cursorPos = cursorPos + 1
                updateInput()
            end
            
        elseif keyCode == keys.home then
            cursorPos = 1
            updateInput()
            
        elseif keyCode == keys["end"] then
            cursorPos = #input + 1
            updateInput()
            
        elseif keyCode == keys.delete then
            if cursorPos <= #input then
                input = input:sub(1, cursorPos - 1) .. input:sub(cursorPos + 1)
                sendData({ type = "control", data = "delete" })
                updateInput()
            end
        end
        
    elseif event == "terminate" then
        print("\nWireless keyboard stopped.")
        break
    end
end