local serial = require "serialization"
local dl = require "download"
local pkg = {}
pkg.cfgPath = "/boot/cfg/pkg"
pkg.sourcePath = pkg.cfgPath .. "/sources.cfg"
pkg.installedPath = pkg.cfgPath .. "/installed.cfg"
require("pkgfs")

local function getSources()
 local f = io.open(pkg.sourcePath,"rb")
 if not f then return {} end
 local c = f:read("*a")
 f:close()
 return serial.unserialize(c)
end
local function saveSources(t)
 fs.makeDirectory(pkg.cfgPath)
 local f = io.open(pkg.sourcePath,"wb")
 f:write(serial.serialize(t))
 f:close()
end

local function getInstalled()
 local f = io.open(pkg.installedPath,"rb")
 if not f then return {} end
 local c = f:read("*a")
 f:close()
 return serial.unserialize(c)
end
local function saveInstalled(t)
 fs.makeDirectory(pkg.cfgPath)
 local f = io.open(pkg.installedPath,"wb")
 if not f then return false end
 f:write(serial.serialize(t))
 f:close()
end

local function getRepoMeta(repo)
 if not getSources()[repo].cache or not fs.exists("/boot/cfg/pkg/repo-"..repo..".cfg") then
  dl(getSources()[repo].path.."/packages.cfg","/boot/cfg/pkg/repo-"..repo..".cfg")
 end
 local f = io.open("/boot/cfg/pkg/repo-"..repo..".cfg","rb")
 local rt = serial.unserialize(f:read("*a"))
 f:close()
 if not getSources()[repo].cache then
  fs.remove("/boot/cfg/pkg/repo-"..repo..".cfg")
 end
 return rt
end

local function activatePackage(path,compressed)
 require("pkgfs").add(path,compressed)
end
local function deactivatePackage(path)
 require("pkgfs").remove(path)
end

function pkg.addRepo(name,path,cache) -- string string boolean -- boolean -- Adds a repository, referred to as *name*, to the list of package sources, with the remote path *path*. If *cache* is set, keep a local copy of the repository index.
 local sources = getSources()
 sources[name] = {path=path,cache=cache,name=name}
 saveSources(sources)
end

function pkg.delRepo(name) -- string -- boolean -- Removes a repository from the list of repositories.
 local sources = getSources()
 sources[name] = nil
 saveSources(sources)
end

function pkg.update() -- Re-download cached repository indexes.
 for repo,meta in pairs(getSources()) do
  fs.remove("/boot/cfg/pkg/repo-"..repo..".cfg")
  if meta.cache then
   getRepoMeta(repo)
  end
 end
end

function pkg.list(filter) -- string -- -- Print a list of available packages matching *filter*.
 filter = filter or ""
 local pkglist = {}
 for repo,_ in pairs(getSources()) do
  for pkg,meta in pairs(getRepoMeta(repo)) do
   if pkg:find(filter) or (pkg.meta or ""):find(filter) then
    meta.repo = repo
    pkglist[pkg] = meta
   end
  end
 end
 for k,v in pairs(pkglist) do
  print(string.format("%s/%s\n %s",v.repo,k,v.description))
 end
end

function pkg.getMeta(pkgname) -- string -- table -- Returns the metadata for a the package specified in *pkgname*.
 print("Finding package "..pkgname)
 for repo,info in pairs(getSources()) do
  local pkg = getRepoMeta(repo)[pkgname]
  if pkg then
   print("Package "..pkgname.." located in repo "..repo.." at "..info.path)
   pkg.repository = info
   return pkg
  end
 end
end

function pkg.get(pkgname,auto) -- string boolean -- boolean -- Downloads and mounts a package, identified as *pkgname*, onto the pkgfs.
 local pkginfo = pkg.getMeta(pkgname)
 if not pkginfo then error("unable to locate package "..pkgname) end
 pkginfo.manual = not auto
 fs.makeDirectory("/boot/pkg")
 for k,v in ipairs(pkginfo.dependencies or {}) do
  if not getInstalled()[v] then
   pkg.get(v)
  end
 end
 dl(pkginfo.repository.path.."/"..pkginfo.filename,"/boot/pkg/"..pkginfo.filename)
 local installed = getInstalled()
 installed[pkgname] = pkginfo
 saveInstalled(installed)
 pcall(activatePackage,"/boot/pkg/"..pkginfo.filename,pkginfo.compressed)
 return true
end

function pkg.upgrade(force) -- boolean -- boolean -- Upgrades all packages on the system to the current version stored in the relevant repository. If *force* is set, re-download all packages.
 pkg.update()
 fs.makeDirectory("/boot/pkg")
 local installed = getInstalled()
 for repo,info in pairs(getSources()) do
  for pkgname,pkginfo in pairs(getRepoMeta(repo)) do
   if installed[pkgname] and pkginfo.version ~= installed[pkgname].version or force then
    pkg.remove(pkgname)
    dl(info.path.."/"..pkginfo.filename,"/boot/pkg/"..pkginfo.filename)
    installed[pkgname] = pkg
    pcall(activatePackage,"/boot/pkg/"..pkginfo.filename,pkginfo.compressed)
   end
  end
 end
 saveInstalled(installed)
end

function pkg.remove(pkgname) -- string -- boolean -- Remove the package *pkgname* from the pkgfs and package directory.
 local installed = getInstalled()
 local pkginfo = installed[pkgname]
 if not pkginfo then return true end
 pcall(deactivatePackage,"/boot/pkg/"..pkginfo.filename)
 fs.remove("/boot/pkg/"..pkginfo.filename)
 installed[pkgname] = nil
 saveInstalled(installed)
 return true
end

return pkg