github

local JSON = dofile("apis/dkjson")

-- Build a github API url, with authorization headers.
local function getAPI(path, auth)
	local url = ('https://api.github.com/%s'):format(path)
	local headers
	if auth and auth.type == 'oauth' then
		headers = { ['Authorization'] = ('token %s'):format(auth.token) }
	end
	local req = http.get(url, headers)
	if req then
		return req.getResponseCode(), JSON.decode(req.readAll())
	else
		return nil, {}
	end
end

local function encodeURI(s)
	return s:gsub(' ', '%%20')
end

-- A class for authorization
local authFile = '.github-auth'
local function writeAuth(data)
	f = fs.open(authFile, 'w')
	f.write(textutils.serialize(data))
	f.close()
end
local function getAuthTable()
	local authTable = {}
	if fs.exists(authFile) then
		f = fs.open(authFile, 'r')
		authTable = textutils.unserialize(f.readAll())
		f.close()
	end
	return authTable
end
local Auth = {}
Auth.__index = Auth
Auth.new = function(type, user, token)
	return setmetatable({type=type, user=user, token=token}, Auth)
end
Auth.get = function(user)
	local authTable = getAuthTable()
	local auth = authTable[user]
	if auth then
		auth = Auth.new(auth.type, auth.user, auth.token)
	end
	return auth
end
Auth.checkToken = function(self)
	local status, request = getAPI('user', self)
	return status == 200
end
Auth.save = function(self)
	local authTable = getAuthTable()
	authTable[self.user] = self
	writeAuth(authTable)
end
Auth.delete = function(user)
	local authTable = getAuthTable()
	authTable[user] = nil
	writeAuth(authTable)
end

-- A class for a blob (aka a file)
local Blob = {}
Blob.__index = Blob
Blob.new = function(repo, sha, path)
	return setmetatable({repo=repo, sha=sha, path=path}, Blob)
end
Blob.fullPath = function(self)
	if self.parent then
		return fs.combine(self.parent:fullPath(), self.path)
	else
		return self.path
	end
end

-- A class for a tree (aka a folder)
local Tree = {}
Tree.__index = Tree
Tree.new = function(repo, sha, path)
	local url = ('repos/%s/%s/git/trees/%s'):format(repo.user, repo.name, sha)
	local status, data = getAPI(url, repo.auth)
	if not status then
		error('Could not get github API from ' ..url)
	end
	if data.tree then
		local tree = setmetatable({
			repo=repo, sha=data.sha,
			path=path or '', size=0,
			contents={}
		}, Tree)
		for _, childdata in ipairs(data.tree) do
			childdata.fullPath = fs.combine(tree:fullPath(), childdata.path)
			local child
			if childdata.type == 'blob' then
				child = Blob.new(repo, childdata.sha, childdata.path)
				child.size = childdata.size
			elseif childdata.type == 'tree' then
				child = Tree.new(repo, childdata.sha, childdata.path)
			else
				error("uh oh", JSON.encode(childdata))
				child = childdata
			end
			tree.size = tree.size + child.size
			child.parent = tree
			table.insert(tree.contents, child)
		end
		return tree
	else
		error("uh oh", JSON.encode(data))
	end
end
local function walkTree(t, level)
	for _, item in ipairs(t.contents) do
		coroutine.yield(item, level)
		if getmetatable(item) == Tree then
			walkTree(item, level + 1)
		end
	end
end
Tree.iter = function(self)
	return coroutine.wrap(function()
		walkTree(self, 0)
	end)
end
Tree.cloneTo = function(self, dest, onProgress)
	if not fs.exists(dest) then
		fs.makeDir(dest)
	elseif not fs.isDir(dest) then
		return error("Destination is a file!")
	end

	for item in self:iter() do
		local gitpath = item:fullPath()
		local path = fs.combine(dest, gitpath)
		if getmetatable(item) == Tree then
			fs.makeDir(path)
		elseif getmetatable(item) == Blob then
			local data = http.get(
				('https://raw.github.com/%s/%s/%s/%s'):format(
					self.repo.user, self.repo.name, self.sha,
					encodeURI(gitpath)
				)
			)
			local h = fs.open(path, 'w')
			local text = data.readAll()
			h.write(text)
			h.close()
		end
		if onProgress then onProgress(item) end
	end
end
Tree.fullPath = Blob.fullPath

-- A class for a release
local Release = {}
Release.__index = Release
Release.new = function(repo, tag)
	return setmetatable({repo=repo, tag=tag}, Release)
end
Release.tree = function(self)
	return self.repo:tree(self.tag)
end

-- A class for a repository
local __repoPriv = setmetatable({}, {mode='k'})
local Repository = {}
Repository.__index = Repository
Repository.new = function(user, name, auth)
	local r = setmetatable({user=user, name=name, auth=auth}, Repository)
	__repoPriv[r] = {trees={}}
	return r
end
Repository.tree = function(self, sha)
	sha = sha or "master"
	if not __repoPriv[self].trees[sha] then
		__repoPriv[self].trees[sha] = Tree.new(self, sha)
	end
	return __repoPriv[self].trees[sha]
end
local function releaseFromURL(url, repo)
	local status, data = getAPI(url, repo.auth)
	if not status then
		error('Could not get release github API from ' .. url)
	end
	-- format is described at https://developer.github.com/v3/repos/releases/
	return Release.new(repo, data["tag_name"])
end
Repository.latestRelease = function(self)
	return releaseFromURL(('repos/%s/%s/releases/latest'):format(self.user, self.name), self)
end
Repository.releaseForTag = function(self, tag)
	return releaseFromURL(('repos/%s/%s/releases/tags/%s'):format(self.user, self.name, tag), self)
end
Repository.__tostring = function(self) return ("Repo@%s/%s"):format(self.user, self.name) end

-- Export members
local github = {}
github.Repository = Repository
github.Blob = Blob
github.Tree = Tree
github.Auth = Auth
github.Release = Release
github.repo = Repository.new
return github