local args = {...}
local internet=require("internet")
local text=require("text")
local filesystem=require("filesystem")
local unicode=require("unicode")
local term=require("term")
local event=require("event")
local keyboard=require("keyboard")

local repository = "seesberger/PowerManager"
local targetFilepath = "/usr/PowerManager/"

local helpText =        "Usage:\n" .. "updater <nothing>  - manual update and install\n".."updater    -h      - this particular text\n" .. "  ''       -a      - automatic update no install\n" .. "  ''       -i      - automatic update and install"

function manualUpdate()
    downloadRepo(repository, targetFilepath, false)
end

function manualInstall()
    os.execute(targetFilepath.."installer.lua -m")
end

function automaticUpdate()
    downloadRepo(repository, targetFilepath, true)
end

function automaticInstall()
    os.execute(targetFilepath.."installer.lua -a")
end

function downloadRepo(repo, target, auto)

    if not repo:match("^[%w-.]*/[%w-.]*$") then
        print('"'..repo..'" does not look like a valid repo identifier.\nShould be <owner>/<reponame>')
        return
    end

    target=target and ("/"..target:match("^/?(.-)/?$").."/") or "/tmp/"..repo
    if filesystem.exists(target) then
        if not filesystem.isDirectory(target) then
            print("target directory already exists and is not a directory.")
            return
        end
        if filesystem.get(target).isReadOnly() then
            print("target directory is read-only.")
            return
        end
    else
        if not filesystem.makeDirectory(target) then
            print("target directory is read-only")
            return
        end
    end



    -- this isn't acually used, but it is tested and works on decoding the base64 encoded data that github
    --sends for some queries, leaving it in here for possible future/related use, might be able to pull
    --and display difs and things like that?
    local symb="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

    function decode64(text)
        local val,bits=0,0
        local output=""
        for ch in text:gmatch(".") do
            if symb:find(ch) then
            --print("ch "..ch.."-> "..(symb:find(ch)-1))
            val=bit32.lshift(val,6)+symb:find(ch)-1
            else
            print(ch.."?")
            return
            end
            bits=bits+6
            --print("bits : "..bits)
            --print(string.format("val : 0x%04x",val))
            if bits>=8 then
            local och=unicode.char(bit32.rshift(val,bits-8))
            --print("os<<"..och)
            --print("& with "..(2^(bits-8)-1))
            val=bit32.band(val,2^(bits-8)-1)
            bits=bits-8
            --print(string.format("val : 0x%04x",val))
            output=output..och
            end
        end
        return output
    end



    local function gitContents(repo, dir)
        print("fetching contents for "..repo..dir)
        local url="https://api.github.com/repos/"..repo.."/contents"..dir
        local result,response=pcall(internet.request,url)
        local raw=""
        local files={}
        local directories={}

        if result then
            for chunk in response do
            raw=raw..chunk
            end
        else
            error("you've been cut off. Serves you right.")
        end

        response=nil
        raw=raw:gsub("%[","{"):gsub("%]","}"):gsub("(\".-\"):(.-[,{}])",function(a,b) return "["..a.."]="..b end)
        local t=load("return "..raw)()

        for i=1,#t do
            if t[i].type=="dir" then
            table.insert(directories,dir.."/"..t[i].name)

            local subfiles,subdirs=gitContents(repo,dir.."/"..t[i].name)
            for i=1,#subfiles do
                table.insert(files,subfiles[i])
            end
            for i=1,#subdirs do
                table.insert(directories,subdirs[i])
            end
            else
            files[#files+1]=dir.."/"..t[i].name
            end
        end

        return files, directories
    end

    local files,dirs=gitContents(repo,"")

    for i=1,#dirs do
        print("making dir "..target..dirs[i])
        if filesystem.exists(target..dirs[i]) then
            if not filesystem.isDirectory(target..dirs[i]) then
            print("error: directory "..target..dirs[i].." blocked by file with the same name")
            return
            end
        else
            filesystem.makeDirectory(target..dirs[i])
        end
    end

    local replaceMode="ask"
    if auto then replacemode = "always" end
    for i=1,#files do
        local replace=nil
        if filesystem.exists(target..files[i]) then
            if filesystem.isDirectory(target..files[i]) then
            print("Error: file "..target..files[i].." blocked by directory with same name!")
            return
            end
            if replaceMode=="always" then
            replace=true
            elseif replaceMode=="never" then
            replace=false
            else
            print("\nFile "..target..files[i].." already exists.\nReplace with new version?")
            local response=""
            while replace==nil do
                term.write("yes,no,always,skip all[ynAS]: ")
                local char
                repeat
                _,_,char=event.pull("key_down")
                until not keyboard.isControl(char)
                char=unicode.char(char)
                print(char)
                if char=="A" then
                replaceMode="always"
                replace=true
                char="y"
                elseif char=="S" then
                replaceMode="never"
                replace=false
                char="n"
                elseif char:lower()=="y" then
                replace=true
                elseif char:lower()=="n" then
                replace=false
                else
                print("invalid response.")
                end
            end
        end
        if replace then
        filesystem.remove(target..files[i])
        end
    end
    if replace~=false then
        print("downloading "..files[i])
        local url="https://raw.github.com/"..repo.."/master"..files[i]
        local result,response=pcall(internet.request,url)
        if result then
            local raw=""
            for chunk in response do
                raw=raw..chunk
            end
            print("writing to "..target..files[i])
            local file=io.open(target..files[i],"w")
            file:write(raw)
            file:close()

            else
            print("failed, skipping")
            end
        end
    end
end

if #args<1 then
    print("No Arguments given. Manual process...")
    manualUpdate()
    return
end

if args == "-h" then
    print(helpText)
    return
elseif args == "-a" then
    automaticUpdate()
    return
elseif args == "-i" then
    automaticUpdate()
    automaticInstall()
    return
else
    print('"'..args[1]..'" - Bad argument.')
    print(helpText)
    return
end