-- ===================================================================
-- /orgs.lua
-- Org-related functions for Modular Politics
-- Called by modpol/modpol/api.lua
-- ===================================================================
-- preserve records -- if true, will store org ledgers when they are closed, for later reference.
local preserve_records = true
modpol.default_org_policies = modpol.default_org_policies or {}


-- initiate the table of orgs

modpol.orgs = {} 
if preserve_records then
   modpol.old_ledgers = {} -- a backup of all legders of all closed orgs.
end


--define the template of a ledger entry
modpol.ledger_entry_temp = {
   timestamp = '',
   entrytype = nil,
   action_msg = '',
   org_name = nil,
}


-- define the basic template of an org.

modpol.org_temp = {
   name = nil,
   policies = {},
   members = {},
   ledger = {},
   parent = nil,
   children = {},
   properties = {},
   old_names = {},

}

-- ===================================================================
-- Function: modpol.create_ledger_entry
-- Params: strings action_msg, org_name, type
-- Outputs:
-- returns a ledger entry table, with a timestamp
-- This function accepts a message and an optional org_name and type specification
-- and returns a valid ledger entry table

modpol.create_ledger_entry = function(action_msg, org_name, entry_type)
   local entry = modpol.ledger_entry_temp
   if action_msg and type(action_msg) == 'string' then
      entry.action_msg = action_msg
   end
   if org_name and type(org_name) == 'string' and modpol.orgs [org_name] then
      entry.org_name = org_name
   end
   if entry_type and type(entry_type) == 'string' then
      entry.entrytype = entry_type
   end
   entry.timestamp = os.time()
   return entry
end


-- ===================================================================
-- Function: modpol.record
-- Params: strings msg, org, type
-- Outputs:
-- "msg" specifies an event and/or status message.
-- "org" specifies an "org" name.
-- "type" -- optional type of legder entry. Could be e.g. 'election_result', 'add_member', etc
-- This  function adds  the message to a  global ledger  and, if "org"
-- specifies a valid "org", to an "org"-specific ledger. Both the mem-
-- ory-resident and on-disk copies of the data structures used are up-
-- dated.

modpol.record = function (org_name, msg, type)

   local entry = modpol.create_ledger_entry(msg,org_name,type)
                                -- Record in global ledger
   table.insert (modpol.ledger, entry)
                                -- Record in "org"-specific ledger
   if modpol.orgs [org_name] ~= nil then
        local org_ledger =  modpol.orgs [org_name]["ledger"]
        if    org_ledger == nil then
            modpol.orgs [org_name]["ledger"] = { entry }
        else
            modpol.orgs [org_name]["ledger"] =
                table.insert (org_ledger, entry)
        end
    end

    modpol.store_data()         -- Copy data to disk
end

-- ===================================================================
-- Function: modpol.add_org
-- Params:   string name, table members, string parent, table properties

-- Output:
--
-- This function creates an "org".  It returns a boolean success indicator and
-- either an error message starting with "Error:" or a success message.
--
-- The string parameter specifies the "org" name.
--
-- The members table should  be an  integer-indexed array of member
-- names.

-- parent should be nil or a valid existing org name. If nil, defaults to 
-- 'instance'

-- properties defaults to an empty table. Use it to initialize the org 
-- with arbitrary properties

modpol.add_org = function(org_name, members, parent, properties)
    local str

    if modpol.ocutil.str_empty (org_name) then
        return false,"Error: Org needs a name"
    end

    if parent and not modpol.orgs[parent] then 
      return false,"Error: Parent must be a valid org"
    end

    if properties and not type(properties) == 'table' then
      return false,"Error: Properties must be a table"
    end

    modpol.ocutil.log ("Adding org " .. org_name)
    if modpol.orgs [org_name] ~= nil then
        str = "Error: Org " .. org_name .. " already exists"
        modpol.ocutil.log (str)
        return false,str
    end

    local parent_org = parent or 'instance'
    local props = properties or {}

   
    -- actually add the org
    local org = modpol.org_temp
    local default_policies = modpol.default_org_policies or {}
    org.name = org_name -- do not change this without the proper api function. This is only a reference, not the only place this is recorded.
    org.members = members
    org.parent = parent_org
    org.properties = props
    org.policies = default_policies

    modpol.orgs [org_name] = org

    --record the child org in the parent's children table
    if modpol.orgs[parent_org].children then
      table.insert(modpol.orgs[parent_org].children, org_name)
    else
      modpol.orgs[parent].children = {org_name}
    end

    local msg = "New org: " .. org_name ..
        " (" .. table.concat (members, ", ") .. ")"

   modpol.record (org_name, msg, 'org_init')
   return true, msg
end




-- ===================================================================
-- Function: modpol.remove_org
-- Params:   string name, opt string reason
-- Output:
--
-- This function removes an "org".  It returns a boolean
-- success indicator and either an error message
-- starting with "Error:" or a success message. It also recursively 
-- removes all child orgs, with 'remove parent org' as reason. If 
-- preserve_records is enabled, it logs the removal in the org ledger,
-- and stores the ledger in modpol.old_legders


-- The string parameter specifies the "org" name.
--
-- The reason is an optional string to additionally include in the 
-- log as reason for removal

modpol.remove_org = function (org_name, reason)
   local str
   if not reason then reason = '' end
   if modpol.ocutil.str_empty (org_name) then
       return false,"Error: Specify an org name to remove"
   end

   if org_name == 'instance' then
      return false,"Error: You cannot remove instance"
   end

   modpol.ocutil.log ("Removing org " .. org_name)
   if modpol.orgs [org_name] == nil then
       str = "Error: Cannot remove non-existant org " .. org_name
       modpol.ocutil.log (str)
       return false,str
   end

   --log msg
   local msg = 'Removing org '..org_name ..', reason: '.. reason

   -- actually remove the org
   modpol.record (org_name, msg, 'org_remove')

   -- TODO: if callbacks are implemented, do so here --
   if preserve_records then
      modpol.old_ledgers = modpol.orgs[org_name].ledger
   end

   -- also remove all children
   if modpol.orgs[org_name].children and #modpol.orgs[org_name].children > 0 then
      for _,child_name in pairs(modpol.orgs[org_name].children) do
         modpol.remove_org(child_name, 'remove parent org') --this is recursion. If it gets to be a problem, we will need a separate function
      end
   end

   modpol.orgs[org_name] = nil

  
  return true,msg

end






-- ===================================================================
-- Function: modpol.list_orgs
-- Params:   None
-- Output:
-- This function returns a text-format list of "orgs".  The list shows
-- one "org" per line in the following format:
-- org_name (member, member, ...)
-- If there are no "orgs", the output is an empty string.

modpol.list_orgs  = function()
    local outbuf = ""
    local str
    for org_name, org_data in pairs (modpol.orgs) do
                                -- Process next "org"
                                -- Build string version of member list
        local memcat = org_data ["members"]
        if  modpol.ocutil.str_empty (memcat) then
              memcat = "(empty)"
        else
              memcat = "(" .. table.concat (memcat, ", ") .. ")"
        end
                                -- Build output string
        outbuf = outbuf .. org_name .. " " .. memcat .. "\n"
    end
    return outbuf
end

-- ===================================================================
-- Function: modpol.reset_orgs
-- Params:   None
-- Removes all orgs and recreates blank org "instance" with all
-- current users
-- returns confirmation message

modpol.reset_orgs = function()
   local users = modpol.list_users()
   --store the ledgers in modpol.old_ledgers, and note that each org was closed in each record.
   if preserve_records then
      for name, org in pairs(modpol.orgs) do
         local old_ledger = org.ledger
         table.insert(old_ledger,modpol.create_ledger_entry('Removing org '.. name, name, 'org_purge'))
         table.insert(modpol.old_ledgers, org.ledger)
      end
   end
   modpol.orgs = {}
   local message = "Orgs purged"
   modpol.record(nil, message, 'org_purge')
   modpol.add_org("instance", users)
   return message
end

-- ===================================================================
-- Function: modpol.add_member
-- Params: org (string), member (string)
-- Output:
-- Adds the specified member to the specified org
-- Returns a boolean success indicator and
-- either a confirmation or error message


-- TODO, check that member is a user, if the org_name is not instance

modpol.add_member = function(org_name, member)
   if (modpol.orgs[org_name] == nil) then
      return false,"Error: No such org"
   elseif type(member) ~= 'string' then
      return false,"Error: member is wrong type"
   else
      if modpol.is_member(org_name,member) then
         return false,"Error: " .. member .. " is already a member of " .. org_name
      else
         table.insert(modpol.orgs[org_name]["members"], member)
         local message = member .. " added to org " .. org_name
         modpol.record(org_name, message, 'add_member')
         return true,message
      end
   end
end

-- ===================================================================
-- Function: modpol.is_member
-- Params: org (string), member (string)
-- Output: Boolean depending on membership or nil/error message

modpol.is_member = function(org, member)
   if (modpol.orgs[org] == nil) then
      return nil, "Error: No such org"
   else
      local member_table = modpol.orgs[org]["members"]
      if member_table then
         for index, value in pairs(member_table) do
            if value == member then
               -- match found
               return true
            end
         end
         -- no match found
         return false
      end
      return false      
   end
end

-- ===================================================================
-- Function: modpol.remove_member
-- Params: org (string), member (string)
-- Output:
-- Removes the specified member from the specified org
-- Returns confirmation or error message

function modpol.remove_member(org, member)
   local message = "Error: No such org"
   if (modpol.orgs[org] == nil) then
      return false, message
   else
      local member_table = modpol.orgs[org]["members"]
      if member_table then
         for index, value in pairs(member_table) do
            if value == member then
               -- match found, set to nil
               
               modpol.orgs[org]["members"][value] = nil  
               
               -- TODO: add callbacks here --
               message = member .. " removed from org " .. org
               modpol.record(org_name, message, 'remove_member')
               return true, message
            end
         end
      end
      -- no match found (or org has no members)
      message = member .. " not found in org " .. org
      return false, message
   end
end

-- ===================================================================
-- TKTK
-- rename_org(old_name, new_name)
-- Renames an org 


   





-- ===================================================================
-- POLICIES
-- Each policy is a table with a string for a key. Contents:
-- KEY - name of the policy (string)
-- [member orgs]: external orgs allowed to call policy
-- [function]: the function that initiates the policy
-- ===================================================================

-- ===================================================================
-- modpol.add_policy
-- Adds a policy to an org's [org].policies table
-- Params: org_name (string),
-- policy_name (string),
-- policy_table (table)
-- Output: true if successful, nil if error

-- TKTK NEEDS TO BE REWRITTEN

modpol.add_policy = function(org_name, policy_name, policy_table)
   -- first, basic checks
   local message = "Error: No such org"
   if (modpol.orgs[org_name] == nil) then
      return nil, message
   elseif (modpol[target_function] == nil) then
      message = "Error: No such target function"
      return nil, message
   elseif (modpol[policy_function]) then
      message = "Error: No such policy function"
      return nil, message
   else
      -- okay, proceed
      modpol.orgs[org_name].policies[target_function] = policy_function
      message = "In org " .. org_name .. ", policy for " .. target_function
         .. " set to " .. policy_function
      record(org_name, message)
      return true, message
   end
end

-- ===================================================================
-- End of file.