-- DESCRIPTION: Home Assistant status cards

local CONFIG_PATH = "/plugins/HomeAssistant/config.txt"
local config = { entities = {} }
local cards = {}
local screen = nil
local connecting = false
local connected = false
local needsDraw = true

local function trim(value)
    return value:match("^%s*(.-)%s*$")
end

local function loadConfig()
    local content = fs.readFile(CONFIG_PATH)
    if not content then return "Missing " .. CONFIG_PATH end

    local lineNumber = 0
    for rawLine in (content:gsub("\r", "") .. "\n"):gmatch("(.-)\n") do
        lineNumber = lineNumber + 1
        local line = trim(rawLine)
        if line ~= "" and line:sub(1, 1) ~= "#" then
            local key, value = line:match("^([%w_]+)%s*=%s*(.-)%s*$")
            if not key or value == "" then return "Invalid config line " .. lineNumber end

            if key == "url" then
                config.url = value:gsub("/+$", "")
            elseif key == "token" then
                config.token = value
            elseif key == "entity" then
                if not value:match("^[%w_]+%.[%w_]+$") then return "Invalid entity on line " .. lineNumber end
                config.entities[#config.entities + 1] = value
            else
                return "Unknown config key: " .. key
            end
        end
    end

    if not config.url then return "Config is missing url" end
    if not config.token then return "Config is missing token" end
    if #config.entities == 0 then return "Config has no entities" end
    if #config.entities > 12 then return "Config supports up to 12 entities" end
end

local function jsonString(value)
    local escapes = { ["\\"] = "\\\\", ["\""] = "\\\"", ["\n"] = "\\n", ["\r"] = "\\r", ["\t"] = "\\t" }
    return '"' .. value:gsub('[\\"\n\r\t]', escapes) .. '"'
end

local function templateRequest()
    local lines = {}
    for _, entity in ipairs(config.entities) do
        lines[#lines + 1] = "{{ (state_attr('" .. entity .. "','friendly_name') or '" .. entity .. "') | replace('|','/') }}|" ..
            entity .. "|{{ states('" .. entity .. "') | replace('|','/') }}|{{ (state_attr('" .. entity ..
            "','unit_of_measurement') or '') | replace('|','/') }}"
    end
    return '{"template":' .. jsonString(table.concat(lines, "\n")) .. "}"
end

local function titleCase(value)
    return value:gsub("_", " "):gsub("(%a)([%w']*)", function(first, rest)
        return first:upper() .. rest
    end)
end

local function parseCards(body)
    local result = {}
    for line in (body .. "\n"):gmatch("(.-)\n") do
        local title, entity, value, unit = line:match("^([^|]*)|([^|]*)|([^|]*)|(.*)$")
        if title then
            result[#result + 1] = {
                title = title,
                entity = entity,
                value = titleCase(value),
                detail = unit
            }
        end
    end
    return result
end

local function fetchCards()
    screen = "Loading Home Assistant..."
    needsDraw = true

    local body, status = net.post(config.url .. "/api/template", templateRequest(), {
        Authorization = "Bearer " .. config.token,
        ["Content-Type"] = "application/json"
    })

    if body and status == 200 then
        cards = parseCards(body)
        if #cards == #config.entities then
            screen = nil
        else
            screen = "Invalid Home Assistant response"
        end
    else
        screen = "Home Assistant error " .. tostring(status)
    end
    needsDraw = true
end

local function drawCardText(font, x, y, width, text, style)
    local textWidth = gui.getTextWidth(font, text, style)
    gui.drawText(font, x + math.floor((width - textWidth) / 2), y, text, COLOR_BLACK, style)
end

local function drawCard(card, x, y, width, height)
    gui.drawRoundedRect(x, y, width, height, 2, 10, COLOR_BLACK)
    gui.drawText(FONT_UI_10, x + 12, y + 10, card.title, COLOR_BLACK, STYLE_BOLD)
    drawCardText(FONT_NOTOSANS_16, x, y + math.floor(height / 2) - 8, width, card.value, STYLE_BOLD)
    if card.detail ~= "" then
        drawCardText(FONT_SMALL, x, y + height - 28, width, card.detail, STYLE_REGULAR)
    end
end

local function render()
    local width, height = gui.width(), gui.height()
    gui.clear()
    gui.drawText(FONT_NOTOSANS_16, 20, 18, "Home Assistant", COLOR_BLACK, STYLE_BOLD)
    gui.drawLine(20, 58, width - 20, 58, 2, COLOR_BLACK)

    if screen then
        gui.drawCenteredText(FONT_UI_12, math.floor(height / 2), screen, COLOR_BLACK, STYLE_REGULAR)
    else
        local columns = width >= 700 and 4 or 2
        local rows = math.ceil(#cards / columns)
        local gap = 10
        local margin = 16
        local top = 72
        local bottom = 58
        local cardWidth = math.floor((width - margin * 2 - gap * (columns - 1)) / columns)
        local cardHeight = math.floor((height - top - bottom - gap * (rows - 1)) / rows)

        for index, card in ipairs(cards) do
            local column = (index - 1) % columns
            local row = math.floor((index - 1) / columns)
            drawCard(card, margin + column * (cardWidth + gap), top + row * (cardHeight + gap), cardWidth, cardHeight)
        end
    end

    gui.drawButtonHints("<<", connected and "Refresh" or "", "", "")
    gui.refresh(REFRESH_HALF)
    needsDraw = false
end

function init()
    local configError = loadConfig()
    if configError then
        screen = configError
        return
    end

    screen = "Connecting to Wi-Fi..."
    connecting = true
    net.wifiConnect()
end

function draw()
    if input.wasPressed("back") then
        if connecting or connected then net.wifiDisconnect() end
        sys.exit()
        return
    end

    if connecting then
        local wifi = net.wifiStatus()
        if wifi == "connected" then
            connecting = false
            connected = true
            fetchCards()
        elseif wifi == "failed" then
            connecting = false
            screen = "Wi-Fi connection failed"
            needsDraw = true
        end
    elseif connected and input.wasPressed("confirm") then
        fetchCards()
    end

    if needsDraw then render() end
end