local ui = require("ui")
-- The same module instance the firmware paints the bar with, so toggling fullscreen
-- through it drops the cache that would otherwise hide the repaint.
local statusbar = require("statusbar")

local INSET = 30
local MENU_PAD, MENU_GAP = 12, 8

local screen, message, passwordLabel, passwordRow
local mode = "menu"
local samples, pending, armed = {}, nil, false
local scanRequested, keyboardRequested = false, false
local selectedNetwork, password = nil, ""
local timezoneCard

local buildMenu, buildWifi, buildNetworks, buildKeyboard, startCalibration, cycleRotation, updatePassword

-- Two inset targets give a raw-per-pixel slope; extrapolate it to the screen edges.
-- Exposed as a global so test/settings_calibration.lua can exercise it.
function computeCalibration(s1, s2, w, h, inset)
  local sx = (s2.x - s1.x) / (w - 2 * inset)
  local sy = (s2.y - s1.y) / (h - 2 * inset)
  return math.floor(s1.x - sx * inset), math.floor(s1.y - sy * inset),
         math.floor(s2.x + sx * inset), math.floor(s2.y + sy * inset)
end

-- When set, a dialog node the current screen is rebuilt with. It is state like `mode`
-- and `message`, not something layered on afterwards, so no screen rebuild can lose it.
local dialog

local function themed(items)
  -- The root carries no padding so a dialog can cover the whole panel; the padded box
  -- is the content it covers. Colors come from the theme by inheritance.
  local content = ui.box(items)
  -- dimmed on the root, not the content: the root is the node that covers the panel, so
  -- the scrim reaches the margins the content box does not.
  screen = ui.screen(dialog and ui.box{dimmed = true, content, dialog} or ui.box{content})
end

local function target(n)
  if n == 1 then return INSET, INSET end
  return 320 - INSET, 480 - INSET
end

local function drawTarget(n)
  local x, y = target(n)
  -- Drawn outside the component tree, so this is the case that reads the theme directly.
  local theme = ui.theme
  gui.clear(theme.bg)
  gui.drawText("tap the cross", 10, 10, theme.fg, theme.bg)
  gui.drawLine(x - 12, y, x + 12, y, theme.accent)
  gui.drawLine(x, y - 12, x, y + 12, theme.accent)
end

local function finishCalibration()
  local ok = settings.setCalibration(computeCalibration(samples[1], samples[2], 320, 480, INSET))
  message = ok and "calibration saved" or "save failed"
  mode = "menu"
  gui.setRotation(settings.getRotation())
  statusbar.setFullscreen(false)
  buildMenu()
end

function startCalibration()
  message = nil
  mode = "calibrate"
  samples, pending, armed = {}, nil, false
  gui.setRotation(0)
  -- The targets sit at the physical corners and the samples are read in panel
  -- coordinates, so the status bar cannot be allowed to shift the frame.
  statusbar.setFullscreen(true)
  drawTarget(1)
end

function cycleRotation()
  local ok = settings.setRotation((settings.getRotation() + 90) % 360)
  message = ok and "rotation saved" or "save failed"
  buildMenu()
end

local function cycleTheme()
  local names = ui.themeNames()
  local next_index = 1
  for index, name in ipairs(names) do
    if name == ui.themeName then next_index = index % #names + 1 end
  end
  local ok = ui.setTheme(names[next_index])
  message = ok and "theme saved" or "save failed"
  buildMenu()
end

local zones = require("timezones")

-- The stored value is a POSIX rule, so a zone set by hand and missing from the list
-- shows its rule rather than pretending to be the first entry.
local function zoneLabel()
  local current = settings.getTimezone()
  for _, zone in ipairs(zones) do
    if zone.tz == current then return zone.name end
  end
  return current
end

local function cycleTimezone()
  local current = settings.getTimezone()
  local next_index = 1
  for index, zone in ipairs(zones) do
    if zone.tz == current then next_index = index % #zones + 1 end
  end
  local ok = settings.setTimezone(zones[next_index].tz)
  ui.setText(timezoneValue, ok and zoneLabel() or "save failed")
  ui.invalidate(timezoneCard)
end

local function wifiValue(status)
  if status.state == "connected" then return status.ssid end
  if status.ssid ~= "" then return status.state end
  return "not set"
end

local function card(side, title, value, on_press)
  local spec = {
    w = side, h = side, gap = 6,
    justify = "center",
    on_press = on_press,
    ui.label(title, {fit = side - 12}),
  }
  local valueLabel
  if value then
    valueLabel = ui.text(value, {w = side - 12, text_align = "center"})
    spec[#spec + 1] = valueLabel
  end
  local button = ui.button(spec)
  if title == "Timezone" then timezoneValue = valueLabel end
  return button
end

function buildMenu()
  mode = "menu"
  -- No title: the status bar already names the running app. The status line under the
  -- grid is worth its rows, so the cards give it room rather than pushing it off screen.
  local side, cols = ui.cardSide(5, MENU_PAD, MENU_GAP, message and 20 or 0)
  local cards = {
    card(side, "Calibrate", "touch", startCalibration),
    card(side, "Rotation", settings.getRotation() .. " deg", cycleRotation),
    card(side, "WiFi", wifiValue(wifi.getStatus()), buildWifi),
    card(side, "Theme", ui.themeName, cycleTheme),
    card(side, "Timezone", zoneLabel(), cycleTimezone),
  }
  timezoneCard = cards[#cards]

  -- Centred left to right as a unit, like the home grid, and still top aligned.
  local items = {pad = MENU_PAD, gap = MENU_GAP, w = "fill", align = "center"}
  local gridW = cols * side + (cols - 1) * MENU_GAP
  for index = 1, #cards, cols do
    local row = {row = true, gap = MENU_GAP, w = gridW}
    for column = index, math.min(index + cols - 1, #cards) do row[#row + 1] = cards[column] end
    items[#items + 1] = ui.box(row)
  end
  if message then items[#items + 1] = ui.text(message) end
  themed(items)
end

-- Painted here rather than left to draw(): the work these announce blocks the loop, and
-- on_tick runs before draw in the same pass, so the panel would sit on the background
-- ui.screen() cleared it to until the blocking call returned.
local function busy(text)
  themed{w = "fill", h = "fill", justify = "center", align = "center", ui.label(text)}
  screen:draw()
end

local function requestScan()
  mode = "scanning"
  scanRequested = true
  busy("scanning networks...")
end

local function forgetNetwork()
  dialog = nil
  message = wifi.forget() and "wifi forgotten" or "save failed"
  buildWifi()
end

-- Destructive and one tap away from the row above it, which is what a confirm is for.
local function confirmForget()
  dialog = ui.confirm{
    title = "forget network?",
    message = wifi.getStatus().ssid,
    ok = "forget",
    on_ok = forgetNetwork,
    on_cancel = function()
      dialog = nil
      buildWifi()
    end,
  }
  buildWifi()
end

function buildWifi()
  mode = "wifi"
  local status = wifi.getStatus()
  local items = {pad = 12, gap = 8, ui.text("wifi"), ui.text("wifi: " .. wifiValue(status))}
  if status.state == "connected" then
    items[#items + 1] = ui.text("ip: " .. status.ip)
  end
  items[#items + 1] = ui.button{label = "scan networks", on_press = requestScan}
  if status.ssid ~= "" then
    items[#items + 1] = ui.button{label = "forget network", on_press = confirmForget}
  end
  items[#items + 1] = ui.button{label = "back", on_press = buildMenu}
  themed(items)
end

local function connectSelected()
  if not wifi.connect(selectedNetwork.ssid, password) then
    message = "could not save wifi"
    buildWifi()
    return
  end
  mode = "connecting"
  themed{pad = 12, gap = 8,
    ui.text("wifi"),
    ui.text("connecting to " .. selectedNetwork.ssid .. "..."),
    ui.button{label = "back", on_press = buildWifi},
  }
end

local function chooseNetwork(network)
  selectedNetwork, password = {ssid = network.ssid}, ""
  if not network.secure then
    connectSelected()
    return
  end
  keyboardRequested = true
  mode = "password"
  busy("opening keyboard...")
end

-- The network a card stands for, keyed by node id: a node is sixteen bytes in the
-- firmware and carries nothing an app puts on it.
local networkOf = {}

local function selectNetwork(id)
  chooseNetwork(networkOf[id])
end

function buildNetworks(networks)
  mode = "networks"
  local byName = {}
  for _, network in ipairs(networks) do
    local current = byName[network.ssid]
    if network.ssid ~= "" and (not current or network.rssi > current.rssi) then
      byName[network.ssid] = network
    end
  end
  local list = {}
  for _, network in pairs(byName) do list[#list + 1] = network end
  table.sort(list, function(a, b) return a.rssi > b.rssi end)

  local items = {pad = 12, gap = 6, ui.text("wifi networks")}
  for i = 1, math.min(#list, 6) do
    local network = list[i]
    local lock = network.secure and " *" or ""
    local card = ui.button{
      label = network.ssid .. lock .. "  " .. network.rssi,
      on_press = selectNetwork,
    }
    networkOf[card] = network
    items[#items + 1] = card
  end
  log.info("wifi scan found " .. #list .. " networks")
  if #list == 0 then items[#items + 1] = ui.text("no networks found", {color = ui.theme.muted}) end
  items[#items + 1] = ui.button{label = "rescan", on_press = requestScan}
  items[#items + 1] = ui.button{label = "back", on_press = buildWifi}
  themed(items)
end

function updatePassword(value)
  password = value
  ui.setText(passwordLabel, "password: " .. password)
  ui.invalidate(passwordRow)
end

function buildKeyboard()
  screen = nil
  collectgarbage()
  local keyboard = require("keyboard")
  mode = "password"
  passwordLabel = ui.text("password: " .. password)
  passwordRow = ui.box{passwordLabel}
  themed{pad = 8, gap = 5,
    ui.text(selectedNetwork.ssid), passwordRow,
    keyboard.new{
      value = password,
      on_change = updatePassword,
      on_submit = function(value) password = value; connectSelected() end,
    },
  }
  local free, _, largest = sys.getMemory()
  log.info("wifi keyboard ready free=" .. free .. " largest=" .. largest)
end

function init()
  sys.setTickInterval(50)  -- calibration samples the raw panel between draws
  buildMenu()
  log.info("settings ready")
end

function draw()
  if mode ~= "calibrate" then screen:draw() end
end

function on_touch_down(x, y)
  if mode ~= "calibrate" then screen:down(x, y) end
end

function on_touch_up(x, y)
  if mode ~= "calibrate" then screen:up(x, y) end
end

function on_tick()
  if keyboardRequested then
    keyboardRequested = false
    buildKeyboard()
    return
  end
  if scanRequested then
    scanRequested = false
    buildNetworks(wifi.scan())
    return
  end
  if mode == "connecting" then
    local status = wifi.getStatus()
    if status.state == "connected" then
      message = "connected: " .. status.ip
      local free, _, largest = sys.getMemory()
      log.info("wifi connected " .. status.ssid .. " free=" .. free .. " largest=" .. largest)
      buildWifi()
    elseif status.state == "failed" or status.state == "not_found" then
      message = "connection " .. status.state
      log.info("wifi connection " .. status.state)
      buildWifi()
    end
    return
  end
  if mode ~= "calibrate" then return end

  local rx, ry = input.getRawTouch()
  if not armed then
    if not rx then armed = true end
    return
  end
  if rx then
    pending = {x = rx, y = ry}
  elseif pending then
    samples[#samples + 1] = pending
    pending = nil
    if #samples == 1 then drawTarget(2) else finishCalibration() end
  end
end