
--# Notes
--# Notes
--[[
This utility backs up and restores your projects for you, by storing them as images in your Dropbox folder.
Its features are as follows:
1. backs up up behind the scenes every time you change the version number
2. tells you how long it is since the last backup
3. restores your backup into a new project, tabs and all

INSTALLING IT
Copy this project to your Codea, named as Backup

BACKING UP

Include a line like this in your function setup()
b=Backup("MyProject Ver 1.00")

Also create a dependency to the Backup project
(click the + at upper right of screen, find Backup on the project list, and press it)

The utility will only back up when the string in brackets changes. It will create a new image with that name
in your Dropbox folder (you may need to sync to see it). The reason for not backing up every time you run, is that when you are developing, you will try a lot of stuff, and you may get into a mess. You will then want to go back to your last stable version. So the idea is that whenever you are at a checkpoint, make a new version name.

NB each time you run, the utility will tell you how long it is since you last backed up. You can turn this off by adding a second parameter, false, when calling Backup.

RESTORING

Create a new project to hold your restored project, and put this in function setup()
img=readImage("Dropbox:AAA")
r=Restore(img)

Now change the image name to the Dropbox file you want to restore

BEFORE YOU RUN, create a dependency to the Backup project
(click the + at upper right of screen, find Backup on the project list, and press it)

Now run, and when it's done, go back to the code and it should all be there.

Ignatz version 1.10 March 2013

--]]

--# Main

function setup()
    Tests()
end

--[[

Backup file format - version 1

    3 bytes    version number (currently = 1)
    7 bytes    size of file

then for each tab...
    3 bytes    char #!#
               tab name
    3 bytes    char #!#
               tab text

there is no need for a closing marker because we know the file size

NOTES
The version number and size of file are stored digit by digit, so 125 takes 3 chars. It is not easily
feasible to use ASCII encoding to make this more compact (ie 125 translates to one char of ASCII 125),
because Codea only accepts about 80 valid characters. And we can afford a handful of extra bytes.

The tab delimiter similarly has to come from the 80 odd valid characters, and to make it unique, needs to be a character combination never found in normal program text.


--]]


--# Test
function Tests()
    success=true
    success=Test_Headers() --tests that the file headers work
    if success then success=Test_Split("rfv") end --tests that a pile of concatenated tab text can be split accurately
    if success then success=Test_Backup("rfv") end --tests the hol system using the project name provided
end

function Test_Headers()
    print("Testing file headers")
    result=".... passed"
    for i=1,100 do --do some tests
        --random string with specific prefix/suffix where problems are most likely to occur
        txt1="12345"..RandomText(20,1500).."67890"
        txt2=Backup:AddHeader(1,txt1)
        txt3=txt2..RandomText(0,100) --add chars to represent unused part of last col of image
        version,txt4=Restore:StripHeader(txt3)
        if version~="001" then result="Incorrect version" break end
        --if n~=string.len(txt1) then result="Incorrect length" break end
        if txt4~=txt1 then result="Incorrect text" break end
    end
    print(result)
    if result~=".... passed" then
        print("==== Original text ====")
        print(txt1)
        print("Size=",string.len(txt1))
        print("==== Text with header ====")
        print(txt2)
        print("==== Text with image padding ====")
        print(txt3)
        print("==== Decoded header details ====")
        print("Version",version)
        print("==== Decoded text ====")
        print(txt4)
        return false
    else return true
    end
end

function RandomText(n1,n2,c)
    --create a random string of printable chars
    --if you provide c, it will be used instead (sometimes it's easier to look at a repeated char than randoms)
    Codes="!#&~*+,)/0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ]_`abcdefghijklmnopqrstuvwxyz"
    local t=""
    m=math.random(n1,n2)
    if c==nil then
        for i=1,m do
            x=math.random(1,string.len(Codes))
            t=t..string.sub(Codes,x,x)
        end
    else
        t=string.rep(c,m)
    end
    return t
end

function Test_Split(p)
    print("Testing code splitter")
    delim="#!#"
    tabs={}
    t={}
    tabs=listProjectTabs(p)
    n=#tabs
    txt=""
    for i=1,n do
        t[i]=readProjectTab(p..":"..tabs[i])
        txt=txt..delim..tabs[i]..delim..t[i]
    end
    result=".... passed"
    if n==0 then result="No tabs found" end
    for i=1,n do
        tabName,tabText,txt2=Restore:SplitCode(txt,delim,2)
        if tabName~=tabs[i] then result="Tab name incorrect" j=i break end
        if tabText~=t[i] or tabText=="" or tabText==nil then result="Text incorrect" j=i break end
        txt=txt2
    end
    print(result)
    if result~=".... passed" then
        print("Error in tab",j)
        print("==== Text passed ====")
        print(txt)
        print("==== Remaining text ====")
        print(txt2)
        print("==== Tab name ====")
        print("Correct name",tabs[j])
        print("Recovered name",tabName)
        print("==== Tab text ====")
        print("==Correct text==")
        print(t[j])
        print("==Recovered text==")
        print(tabText)
        return false
    else return true
    end
end

function Test_Backup(p)
    print("Testing complete system")
    b=Backup("Test "..tostring(math.random(1,1000)),true,p)
end


--# Backup
Backup = class()

--title is name of backup, backup only occurs when this changes
--remind parameter if set to false turns off the reminder of how long it has been since last backup
function Backup:init(title,remind,testproject)
    local t=readProjectData(title)
    if t~=nil and remind~=false then
        print("Last backup was",string.format("%.0f",os.difftime(os.time(),t)/60),"minutes ago")
    else
        local version="001"
        local delim="#!#" --tab and tabname delimiter
        self:Store(title,version,delim,testproject)
        saveProjectData(title,os.time())
    end
end

function Backup:Store(title,version,delim,testproject)
    local origTxt=""
    local tabs
    if testproject==nil then tabs=listProjectTabs() else tabs=listProjectTabs(testproject) end
    for i,t in pairs(tabs) do
        local tt=t
        if testproject~=nil then tt=testproject..":"..t end
        origTxt=origTxt..delim..t..delim..readProjectTab(tt)
    end
    local txt=Backup:AddHeader(version,origTxt)     --add file header
    --setup image
    local n=string.len(txt)
    local s=math.floor((n/3)^.5)+1
    local img=image(s,s)
    local row,col=0,1
    local e={}
    local m=0
    for i=0,n-1,3 do
        for j=1,3 do
            e[j]=string.byte(string.sub(txt,i+j,i+j)) or 0
        end
        row = row + 1
        if row>s then row=1 col = col + 1 end
        img:set(col,row,e[1],e[2],e[3],255)
    end
    local docName="Dropbox:"..title
    saveImage(docName,nil)
    saveImage(docName,img)
    print(title.." - backup made")
    --verify image by restoring and comparing result with original
    local r=Restore(img,1)
    if origTxt==r.txt then
        print("Backup verified")
    else
        print("ERROR - backup faulty")
        print(r.txt)
    end
end

--parameters are version number and text
function Backup:AddHeader(v,t)
    local n=tostring(string.len(t) + 10) -- 3 version bytes + 7 length bytes
    return Backup:Pad(tostring(v),3)..Backup:Pad(n,7)..t
end

function Backup:Pad(str,n)
    local m=string.len(str)
    if m>=n then
        return str
    else
        return string.rep("0",n-m)..str
    end
end
--# Restore
Restore = class()

function Restore:init(img,test)
    local txt=self:ReadImage(img)
    if txt=="ERROR" then
        print("ERROR: I couldn't read the backup")
    else
        local version,t=Restore:StripHeader(txt)
        if test==1 then self.txt=t return end
        if version=="001" then
            local delim="#!#" --tab and tabname delimiter
            Restore:SplitCode(t,delim,test)
        end
    end
end

function Restore:ReadImage(img)
    if type(img)=="string" then img=readImage(img) end
    rows,cols=img.height,img.width
    t={}
    local n=0
    local r,g,b
    for col=1,cols do
        for row=1,rows do
            r,g,b=img:get(col,row)
            table.insert(t,string.char(r)) table.insert(t,string.char(g)) table.insert(t,string.char(b))
            n = n + 3
        end
    end
    return table.concat(t)
end

function Restore:SplitCode(str,delim,test)
    local n=string.len(delim)
    local i,j=string.find(str,delim,nil,true)
    while i~=nil and j~=nil do
        local k=string.find(str,delim,j+1,true)
        local tabName=string.sub(str,j+1,k-1)
        i,j=string.find(str,delim,k+n,true)
        if i~=nil then
            tabText=string.sub(str,k+n,i-1)
        else
            tabText=string.sub(str,k+n)
            i=string.len(str)+1
        end
        if test==2 then
            return tabName,tabText,string.sub(str,i)
        elseif test==nil then
            print("Restoring",tabName)
            saveProjectTab(tabName,tabText)
        end
    end
    if test==nil then print("All done!") end
end

function Restore:StripHeader(txt)
    local version=string.sub(txt,1,3)
    local n=tonumber(string.sub(txt,4,10))
    local t=string.sub(txt,11,n)
    return version,t
end