SEE Installer

--JSON functions

--Credit goes to http://www.computercraft.info/forums2/index.php?/topic/5854-json-api-v201-for-computercraft/
------------------------------------------------------------------ utils
local controls = {["\n"]="\\n", ["\r"]="\\r", ["\t"]="\\t", ["\b"]="\\b", ["\f"]="\\f", ["\""]="\\\"", ["\\"]="\\\\"}


local whites = {['\n']=true; ['r']=true; ['\t']=true; [' ']=true; [',']=true; [':']=true}
function removeWhite(str)
    while whites[str:sub(1, 1)] do
        str = str:sub(2)
    end
    return str
end

------------------------------------------------------------------ decoding

function jsonParseBoolean(str)
    if str:sub(1, 4) == "true" then
        return true, removeWhite(str:sub(5))
    else
        return false, removeWhite(str:sub(6))
    end
end

function jsonParseNull(str)
    return nil, removeWhite(str:sub(5))
end

local numChars = {['e']=true; ['E']=true; ['+']=true; ['-']=true; ['.']=true}
function jsonParseNumber(str)
    local i = 1
    while numChars[str:sub(i, i)] or tonumber(str:sub(i, i)) do
        i = i + 1
    end
    local val = tonumber(str:sub(1, i - 1))
    str = removeWhite(str:sub(i))
    return val, str
end

function jsonParseString(str)
    local i,j = str:find('^".-[^\\]"')
    local s = str:sub(i + 1,j - 1)

    for k,v in pairs(controls) do
        s = s:gsub(v, k)
    end
    str = removeWhite(str:sub(j + 1))
    return s, str
end

function jsonParseArray(str)
    str = removeWhite(str:sub(2))

    local val = {}
    local i = 1
    while str:sub(1, 1) ~= "]" do
        local v = nil
        v, str = jsonParseValue(str)
        val[i] = v
        i = i + 1
        str = removeWhite(str)
    end
    str = removeWhite(str:sub(2))
    return val, str
end

function jsonParseObject(str)
    str = removeWhite(str:sub(2))

    local val = {}
    while str:sub(1, 1) ~= "}" do
        local k, v = nil, nil
        k, v, str = jsonParseMember(str)
        val[k] = v
        str = removeWhite(str)
    end
    str = removeWhite(str:sub(2))
    return val, str
end

function jsonParseMember(str)
    local k = nil
    k, str = jsonParseValue(str)
    local val = nil
    val, str = jsonParseValue(str)
    return k, val, str
end

function jsonParseValue(str)
    local fchar = str:sub(1, 1)
    if fchar == "{" then
        return jsonParseObject(str)
    elseif fchar == "[" then
        return jsonParseArray(str)
    elseif tonumber(fchar) ~= nil or numChars[fchar] then
        return jsonParseNumber(str)
    elseif str:sub(1, 4) == "true" or str:sub(1, 5) == "false" then
        return jsonParseBoolean(str)
    elseif fchar == "\"" then
        return jsonParseString(str)
    elseif str:sub(1, 4) == "null" then
        return jsonParseNull(str)
    end
    return nil
end

function jsonDecode(str)
    str = removeWhite(str)
    t = jsonParseValue(str)
    return t
end

function downloadJson(url)
    local file = http.get(url)
    if not file then
        return nil
    end
    return jsonDecode(file.readAll())
end

local GitHubRepo = "Yevano/see" -- Change to user/repo
local GitHubBranch = "master"   -- Change to needed branch
local installPath = "/see/"


local GitHubRef = "refs/heads/"..GitHubBranch
local GitHubRaw = 'https://raw.github.com/'..GitHubRepo..'/'..GitHubBranch..'/'
local args = {...}

local blacklist = {
    '.gitignore',
    'README.md'
}

function isBlacklisted(path)
    for i, item in ipairs(blacklist) do
        if item == path then
            return true
        end
    end
    return false
end

local failed = {}

function downloadBlob(v)
    if isBlacklisted(v.path) then
            return
    end
    --Make dir if needed
    if v.type == 'tree' then
        fs.makeDir(installPath..v.path)
    else
        --Start download
        local url = (GitHubRaw..v.path):gsub(' ','%%20')
        local f = http.get(url)

        --If couldn't download then add to failed
        if not f then
            table.insert(failed,v)
            return
        end

        --Write file
        local h = fs.open(installPath..v.path, 'w')
        h.write(f.readAll())
        h.close()
    end
end

local function fail(err)
    printError(err)

    while true do
        write("Retry installation? (y/n): ")
        local response = read()
        if string.lower(response):gsub("%s", "") == "y" then
            return true
        elseif string.lower(response):gsub("%s", "") == "n" then
            return false
        end
        print("Invalid input.")
    end
end

--Get install directory
while true do
    if #args == 1 then
        installPath = args[1]
    else
        write("Choose an install path: ")
        installPath = "/" .. shell.resolve(read())
    end

    local configHandle = fs.open("/.see", "w")
    configHandle.write('install_dir = "' .. installPath .. '/see"')
    configHandle.close()

    local suc, err = pcall(fs.makeDir, installPath)
    if not suc then
        if not fail("Could not create installation directory.") then error("Exiting") end
    else
        break
    end
end

installPath = installPath .. '/'
local tree = {}
local latestSha = ''

--Get latest commit
while true do
    --Get sha for specific branch
    local refs = downloadJson('https://api.github.com/repos/'..GitHubRepo..'/git/refs')

    if refs == nil then
        if not fail("Could not fetch branches") then error("Exiting") end
    else
        for i, v in ipairs(refs) do
            if v.ref == GitHubRef then
                latestSha = v.object.sha
                break
            end
        end
        break
    end
end
--Get tree
while true do
    --Download file list
    tree = downloadJson('https://api.github.com/repos/'..GitHubRepo..'/git/trees/'..latestSha..'?recursive=1').tree

    if tree == nil then
        if not fail("Could not fetch tree") then error("Exiting") end
    else
        break
    end
end

--Prepare file download
local downloads = {}
for i, v in ipairs(tree) do
    table.insert(downloads, function()downloadBlob(v)end)
end

while true do
    parallel.waitForAll(unpack(downloads))

    if #failed > 0 then
        if not fail("Not all files downloaded. Retry?") then error("Exiting") end

        downloads = {}
        for i, v in ipairs(failed) do
            print("Retrying "..v.path)
            table.insert(downloads, function()downloadBlob(v)end)
        end
        failed = {}
    else
        break
    end
end