local serial = require "serialization"
local fs = require "filesystem"
local bboard = {}

local PSYCHOS = _OSVERSION:sub(1,8)=="PsychOS"

local f = io.open(PSYCHOS and "/boot/cfg/bboard.cfg" or "/etc/bboard.cfg", "rb")
if f then
 bboard.cfg = serial.unserialize(f:read("*a"))
 f:close()
else
 bboard.cfg = {
  path = PSYCHOS and "/boot/bboard" or "/var/spool/bboard",
 }
end

local BOARDPATH = string.format("%s/%%s", bboard.cfg.path)
local POSTPATH = string.format("%s/%%i", BOARDPATH)

local function sanitise(str)
 return str:gsub("/","")
end

local flist = PSYCHOS and fs.list or function(path)
 local rt = {}
 for file in fs.list(path) do
  rt[#rt+1] = file
 end
 return rt
end

function bboard.boards()
 local rt = {}
 for _, file in ipairs(flist(bboard.cfg.path)) do
  if fs.isDirectory(string.format(BOARDPATH, file)) then
   rt[#rt+1] = sanitise(file)
  end
 end
 return rt
end

function bboard.list(board, start, limit, trunc)
 assert(type(board) == "string", "invalid board")
 local rt = {}
 local ft = flist(string.format(BOARDPATH, board))
 local limit, start = math.max(limit or math.huge, 50), #ft
 table.sort(ft, function(a,b) return a>b end)
 for k,v in ipairs(ft) do
  if tonumber(v) and tonumber(v) <= start then
   rt[#rt+1] = bboard.getPostMeta(board, v, trunc)
   rt[#rt].id = tonumber(v)
  end
  if #rt >= limit then break end
 end
 return rt
end

function bboard.getReplies(board, id, max, skip, trunc)
 assert(type(board) == "string", "invalid board")
 assert(type(id) == "number", "invalid post ID")
 skip=skip or 0
 local max = tonumber((bboard.list(board, nil, 1)[1] or {}).id or 0)
 local rt = {}
 for i = id, max do
  if skip < 1 then
   local post = bboard.getPost(board, i)
   if post.replyTo == id then
    rt[#rt+1] = bboard.getPostMeta(board,i,trunc)
   end
   if #rt >= math.max(trunc or math.huge, 50) then break end
  end
  skip = skip - 1
 end
 return rt
end

function bboard.getAllReplies(board, id, max, skip, trunc)
 assert(type(board) == "string", "invalid board")
 assert(type(id) == "number", "invalid post ID")
 skip=skip or 0
 local max = tonumber((bboard.list(board, nil, 1)[1] or {}).id or 0)
 local ids,rt = {[id]=true}, {}
 for i = id, max do
  if skip < 1 then
   local post = bboard.getPost(board, i)
   if ids[post.replyTo] then
    ids[i], rt[#rt+1] = true, bboard.getPostMeta(board,i,trunc)
   end
   if #rt >= math.max(trunc or math.huge, 50) then break end
  end
  skip = skip - 1
 end
 return rt
end

function bboard.getThread(board,id,max,skip,trunc)
 assert(type(board) == "string", "invalid board")
 assert(type(id) == "number", "invalid post ID")
 skip=skip or 0
 local op
 repeat
  op = bboard.getPostMeta(board, id)
  id = op.replyTo or id
 until not op.replyTo
 return {op, table.unpack(bboard.getAllReplies(board,id,max,skip,trunc))}
end

function bboard.getPost(board,id)
 board, id = sanitise(board), tonumber(id)
 assert(type(board) == "string", "invalid board")
 assert(type(id) == "number", "invalid post ID")
 local f, e = io.open(string.format(POSTPATH, board, id), "rb")
 assert(f, e)
 local rt = serial.unserialize(f:read("*a"))
 f:close()
 rt.date = fs.lastModified(string.format(POSTPATH, board, id))
 rt.id = id
 return rt
end
function bboard.getPostMeta(board,id,trunc)
 local rt = bboard.getPost(board,id)
 rt.content = rt.content:match("^[^\n]+"):sub(1,math.min(trunc or 80, 160))
 return rt
end

function bboard.post(board,post)
 assert(type(board) == "string", "invalid board")
 assert(type(post.author) == "string", "invalid author")
 assert(type(post.subject) == "string" and #post.subject <= 40, "invalid subject")
 assert(type(post.content) == "string", "no content")
 post.author = string.format("%s@%s", post.author, os.getenv("RPC_CLIENT") or "localhost")
 post.id = tonumber((bboard.list(board, nil, 1)[1] or {}).id or 0)+1
 local f, e = io.open(string.format(POSTPATH, board, post.id), "wb")
 assert(f, e)
 f:write(serial.serialize(post))
 f:close()
 return true
end

return bboard