listUILib

page = {}

local g_window_size = { w = 0, h = 0 }

page.mPageIndex = 0
page.mRowIndex = 0
page.mPageCount = 0
page.mItemCount = 0
page.mNowMaxPageIndex = 0
page.topBar = nil
page.body = nil

local g_entry_list = {}

local winNormColor = {
    font = colors.black,
    bg = colors.lime
}

local winFocusColor = {
    font = colors.gray,
    bg = colors.pink
}

-- renewTopBar and Body
local function flushTopBar()
    local str = string.format("%3d/%3d      size:%d",page.mPageIndex,page.mPageCount,page.mItemCount)
    page.topBar.clear()
    page.topBar.setCursorPos(1,1)
    page.topBar.write(str)
end

local function flushBody()
    page.body.clear()
    local nPos = 1
    local startPos = (page.mPageIndex - 1) * g_window_size.h + 1
    local endPos = startPos + page.mNowMaxPageIndex - 1
    for index = startPos, endPos, 1 do
        page.body.setCursorPos(1,nPos)
        if(nPos == page.mRowIndex) then -- select backGround Color
            page.body.setBackgroundColor(winFocusColor.bg)
            page.body.setTextColor(winFocusColor.font)
            page.body.clearLine()
        else
            page.body.setBackgroundColor(winNormColor.bg)
            page.body.setTextColor(winNormColor.font)
        end
        page.body.write(g_entry_list[index])
        nPos = nPos + 1
    end
    page.body.setBackgroundColor(winNormColor.bg)
    page.body.setTextColor(winNormColor.font)
end

-- switch the page
local function pageChange(offset)
    local targetPageIndex = page.mPageIndex + offset
    -- page.LDebug(page.mPageIndex,19)
    targetPageIndex = targetPageIndex > 0 and targetPageIndex or 1
    targetPageIndex = targetPageIndex <= page.mPageCount and targetPageIndex or page.mPageCount
    page.mPageIndex = targetPageIndex
    local remainder = page.mItemCount % g_window_size.h
    if (targetPageIndex == page.mPageCount and remainder ~= 0) then
        -- have remainder
        page.mNowMaxPageIndex = remainder
    else
        -- common page
        page.mNowMaxPageIndex = g_window_size.h
    end

    flushTopBar()
    flushBody()
end

--[[
    the key method for use
]]

-- debug in window
function page.LDebug(str,col)
    term.setCursorPos(1,col)
    term.setTextColor(colors.orange)
    term.setBackgroundColor(colors.white)
    term.clearLine()
    term.write(str)
end

-- init
function page.init(list,width,height)
    g_window_size.w = width
    g_window_size.h = height - 3
    page.topBar = window.create(term.current(), 1, 1, g_window_size.w, 1)
    page.body = window.create(term.current(), 1, 2, g_window_size.w, g_window_size.h)

    page.topBar.setBackgroundColor(colors.orange)
    page.topBar.setTextColor(colors.white)
    page.body.setBackgroundColor(winNormColor.bg)
    page.body.setTextColor(winNormColor.font)
    page.mItemCount = table.getn(list)
    page.mPageCount =  (page.mItemCount - 1 - (page.mItemCount - 1) % g_window_size.h) / g_window_size.h + 1
    page.mPageIndex = 1
    page.mRowIndex = 1
    g_entry_list = list

    term.clear()
    term.setTextColor(colors.white)
    pageChange(0)
end

-- get current select
function page.getSelect()
    local index = (page.mPageIndex -1) * g_window_size.h + page.mRowIndex
    return index
end

local keyMap = {
    ["up"]=(function ()
        if(page.mRowIndex > 1) then
            page.mRowIndex = page.mRowIndex - 1
        -- LDebug("nowPos "..(pageIndex-1) * mh + page.mRowIndex,18)
            flushBody()
        end
    end),
    ["down"]=(function ()
        if(page.mRowIndex < g_window_size.h and page.mRowIndex < page.mNowMaxPageIndex) then
            page.mRowIndex = page.mRowIndex + 1
            -- LDebug("nowPos "..(pageIndex-1) * mh + page.mRowIndex,18)
            flushBody()
        end
    end),
    ["left"]=(function ()
        if(page.mPageIndex > 1) then
            page.mRowIndex = 1
            pageChange(-1)
        end
    end),
    ["right"]=(function ()
        if(page.mPageIndex < page.mPageCount) then
            page.mRowIndex = 1
            pageChange(1)
        end
    end),
}

-- control the page
function page.control(cmd)
    local cb = keyMap[cmd]
    if cb ~= nil then
        keyMap[cmd]()
    end
end