-- if player has npc_talk_owner priv AND is owner of this particular npc:
--   chat option: "I am your owner. I have new orders for you.
--   -> enters edit mode
-- when edit_mode has been enabled, the following chat options are added to the options:
--   chat option: "Add new answer/option to this dialog."
--   -> adds a new aswer/option
--   chat option: "That was all. I'm finished with giving you new orders. Remember them!"
--   -> ends edit mode
--

--###
-- Init
--###

-- store if the player is editing a particular NPC; format: yl_speak_up.edit_mode[pname] = npc_id
yl_speak_up.edit_mode = {}

-- changes applied in edit_mode are applied immediately - but not immediately stored to disk
-- (this gives the players a chance to back off in case of unwanted changes)
yl_speak_up.npc_was_changed = {}

-- self (the npc as such) is rarely passed on to any functions; in order to be able to check if
-- the player really owns the npc, we need to have that data available;
-- format: yl_speak_up.npc_owner[ npc_id ] = owner_name
yl_speak_up.npc_owner = {}

-- store the current trade between player and npc in case it gets edited in the meantime
yl_speak_up.trade = {}

function yl_speak_up.init_mob_table()
    return false
end


yl_speak_up.reset_vars_for_player = function(pname, reset_fs_version)
	yl_speak_up.speak_to[pname] = nil
	yl_speak_up.edit_mode[pname] = nil
	-- when just stopping editing: don't reset the fs_version
	if(reset_fs_version) then
		yl_speak_up.fs_version[pname] = nil
	end
end

minetest.register_on_leaveplayer(
    function(player)
	yl_speak_up.reset_vars_for_player(player:get_player_name(), true)
    end
)

minetest.register_on_joinplayer(
    function(player)
	yl_speak_up.reset_vars_for_player(player:get_player_name(), true)
    end
)

--###
-- Debug
--###

yl_speak_up.debug = true

--###
-- Helpers
--###

yl_speak_up.get_number_from_id = function(any_id)
    if(any_id == "d_got_item") then
        return "0"
    end
    return string.split(any_id, "_")[2]
end

local function save_path(n_id)
    return yl_speak_up.worldpath .. yl_speak_up.path .. DIR_DELIM .. n_id .. ".json"
end

yl_speak_up.get_error_message = function()
    local formspec = {
        "size[13.4,8.5]",
        "bgcolor[#FF0000]",
        "label[0.2,0.35;Please save a NPC file first]",
        "button_exit[0.2,7.7;3,0.75;button_back;Back]"
    }

    return table.concat(formspec, "")
end

yl_speak_up.find_next_id = function(t)
    local start_id = 1

    if t == nil then
        return start_id
    end

    local keynum = 1
    for k, _ in pairs(t) do
        local keynum = tonumber(yl_speak_up.get_number_from_id(k))
        if keynum >= start_id then
            start_id = keynum + 1
        end
    end
    return start_id
end

yl_speak_up.sanitize_sort = function(options, value)
    local retval = value

    if value == "" or value == nil or tonumber(value) == nil then
        local temp = 0
        for k, v in pairs(options) do
            if v.o_sort ~= nil then
                if tonumber(v.o_sort) > temp then
                    temp = tonumber(v.o_sort)
                end
            end
        end
        retval = tostring(temp + 1)
    end
    return retval
end

--###
--Load and Save
--###

-- we can't really log changes here in this function because we don't know *what* has been changed
yl_speak_up.save_dialog = function(n_id, dialog)
    if type(n_id) ~= "string" or type(dialog) ~= "table" then
        return false
    end
    local p = save_path(n_id)
    -- save some data (in particular usage of quest variables)
    yl_speak_up.update_stored_npc_data(n_id, dialog)
    local content = minetest.write_json(dialog)
    return minetest.safe_file_write(p, content)
end


-- if a player is supplied: include generic dialogs
yl_speak_up.load_dialog = function(n_id, player) -- returns the saved dialog
    local p = save_path(n_id)

    local file, err = io.open(p, "r")
    if err then
	return yl_speak_up.add_generic_dialogs({}, n_id, player)
    end
    io.input(file)
    local content = io.read()
    local dialog = minetest.parse_json(content)
    io.close(file)

    if type(dialog) ~= "table" then
        dialog = {}
    end

    return yl_speak_up.add_generic_dialogs(dialog, n_id, player)
end

-- used by staff and input_inital_config
yl_speak_up.fields_to_dialog = function(pname, fields)
    local n_id = yl_speak_up.speak_to[pname].n_id
    local dialog = yl_speak_up.load_dialog(n_id, false)
    local save_d_id = ""

    if next(dialog) == nil then -- No file found. Let's create the basic values
        dialog = {}
        dialog.n_dialogs = {}
    end

    if dialog.n_dialogs == nil or next(dialog.n_dialogs) == nil then --No dialogs found. Let's make a table
        dialog.n_dialogs = {}
    end

    if fields.d_text ~= "" then -- If there is dialog text, then save new or old dialog
        if fields.d_id == yl_speak_up.text_new_dialog_id then --New dialog --
            -- Find highest d_id and increase by 1
            save_d_id = "d_" .. yl_speak_up.find_next_id(dialog.n_dialogs)

            -- Initialize empty dialog
            dialog.n_dialogs[save_d_id] = {}
        else -- Already existing dialog
            save_d_id = fields.d_id
        end
        -- Change dialog
        dialog.n_dialogs[save_d_id].d_id = save_d_id
        dialog.n_dialogs[save_d_id].d_type = "text"
        dialog.n_dialogs[save_d_id].d_text = fields.d_text
        dialog.n_dialogs[save_d_id].d_sort = fields.d_sort
    end

    --Context
    yl_speak_up.speak_to[pname].d_id = save_d_id

    -- Just in case the NPC vlaues where changed or set
    dialog.n_id = n_id
    dialog.n_description = fields.n_description
    dialog.n_npc = fields.n_npc

    dialog.npc_owner = fields.npc_owner

    return dialog
end

yl_speak_up.delete_dialog = function(n_id, d_id)
    if d_id == yl_speak_up.text_new_dialog_id then
        return false
    end -- We don't delete "New dialog"

    local dialog = yl_speak_up.load_dialog(n_id, false)

    dialog.n_dialogs[d_id] = nil

    yl_speak_up.save_dialog(n_id, dialog)
end


--###
--Formspecs
--###

-- get formspecs

-- talk

-- receive fields


-- talk

-- helper function
-- the option to override next_id and provide a value is needed when a new dialog was
-- added, then edited, and then discarded; it's still needed after that, but has to
-- be reset to empty state (wasn't stored before)
yl_speak_up.add_new_dialog = function(dialog, pname, next_id)
	if(not(next_id)) then
		next_id = yl_speak_up.find_next_id(dialog.n_dialogs)
	end
	local future_d_id = "d_" .. next_id
	-- Initialize empty dialog
	dialog.n_dialogs[future_d_id] = {
		d_id = future_d_id,
		d_type = "text",
		d_text = "",
		d_sort = next_id
		}
	-- store that there have been changes to this npc
	-- (better ask only when the new dialog is changed)
--	table.insert(yl_speak_up.npc_was_changed[ yl_speak_up.edit_mode[pname] ],
--		"Dialog "..future_d_id..": New dialog added.")
	return future_d_id
end


-- add a new result to option o_id of dialog d_id
yl_speak_up.add_new_result = function(dialog, d_id, o_id)
	if(not(dialog) or not(dialog.n_dialogs) or not(dialog.n_dialogs[d_id])
	  or not(dialog.n_dialogs[d_id].d_options) or not(dialog.n_dialogs[d_id].d_options[o_id])) then
		return
	end
	-- create a new result (first the id, then the actual result)
	local future_r_id = "r_" .. yl_speak_up.find_next_id(dialog.n_dialogs[d_id].d_options[o_id].o_results)
	if future_r_id == "r_1" then
		dialog.n_dialogs[d_id].d_options[o_id].o_results = {}
	end
	dialog.n_dialogs[d_id].d_options[o_id].o_results[future_r_id] = {}
	return future_r_id
end


-- this is useful for result types that can exist only once per option
-- (apart from editing with the staff);
-- examples: "dialog" and "trade";
-- returns tue r_id or nil if no result of that type has been found
yl_speak_up.get_result_id_by_type = function(dialog, d_id, o_id, result_type)
	if(not(dialog) or not(dialog.n_dialogs) or not(dialog.n_dialogs[d_id])
	  or not(dialog.n_dialogs[d_id].d_options) or not(dialog.n_dialogs[d_id].d_options[o_id])) then
		return
	end
	local results = dialog.n_dialogs[d_id].d_options[o_id].o_results
	if(not(results)) then
		return
	end
	for k, v in pairs(results) do
		if(v.r_type == result_type) then
			return k
		end
	end
end


-- helper function for sorting options/answers using options[o_id].o_sort
-- (or dialogs by d_sort)
yl_speak_up.get_sorted_options = function(options, sort_by)
	local sorted_list = {}
	for k,v in pairs(options) do
		table.insert(sorted_list, k)
	end
	table.sort(sorted_list,
		function(a,b)
			if(not(options[a][sort_by])) then
				return false
			elseif(not(options[b][sort_by])) then
				return true
			-- sadly not all entries are numeric
			elseif(tonumber(options[a][sort_by]) and tonumber(options[b][sort_by])) then
				return (tonumber(options[a][sort_by]) < tonumber(options[b][sort_by]))
			-- numbers have a higher priority
			elseif(tonumber(options[a][sort_by])) then
				return true
			elseif(tonumber(options[b][sort_by])) then
				return false
			-- if the value is the same: sort by index
			elseif(options[a][sort_by] == options[b][sort_by]) then
				return (a < b)
			else
				return (options[a][sort_by] < options[b][sort_by])
			end
		end
	)
	return sorted_list
end


-- simple sort of keys of a table numericly;
-- this is not efficient - but that doesn't matter: the lists are small and
-- it is only executed when configuring an NPC
-- simple: if the parameter is true, the keys will just be sorted (i.e. player names) - which is
-- 	not enough for d_<nr>, o_<nr> etc. (which need more care when sorting)
yl_speak_up.sort_keys = function(t, simple)
	local keys = {}
	for k, v in pairs(t) do
		-- add a prefix so that p_2 ends up before p_10
		if(not(simple) and string.len(k) == 3) then
			k = "a"..k
		end
		table.insert(keys, k)
	end
	table.sort(keys)
	if(simple) then
		return keys
	end
	for i,k in ipairs(keys) do
		-- avoid cutting the single a from a_1 (action 1)
		if(k and string.sub(k, 1, 1) == "a" and string.sub(k, 2, 2) ~= "_") then
			-- remove the leading blank
			keys[i] = string.sub(k, 2)
		end
	end
	return keys
end


-- identify multiple results that lead to target dialogs
yl_speak_up.check_for_disambigous_results = function(n_id, pname)
	local errors_found = false
	-- this is only checked when trying to edit this npc;
	-- let's stick to check the dialogs of this one without generic dialogs
	local dialog = yl_speak_up.load_dialog(n_id, false)
	-- nothing defined yet - nothing to repair
	if(not(dialog.n_dialogs)) then
		return
	end
	-- iterate over all dialogs
	for d_id, d in pairs(dialog.n_dialogs) do
		if(d_id and d and d.d_options) then
			-- iterate over all options
			for o_id, o in pairs(d.d_options) do
				if(o_id and o and o.o_results) then
					local dialog_results = {}
					-- iterate over all results
					for r_id, r in pairs(o.o_results) do
						if(r.r_type == "dialog") then
							table.insert(dialog_results, r_id)
						end
					end
					if(#dialog_results>1) then
						minetest.chat_send_player(pname, "ERROR: Dialog "..
							tostring(d_id)..", option "..tostring(o_id)..
							", has multiple results of type dialog: "..
							minetest.serialize(dialog_results)..". Please "..
							"let someone with npc_master priv fix that first!")
						errors_found = true
					end
				end
			end
		end
	end
	return errors_found
end


-- Make the NPC talk

function yl_speak_up.talk(self, clicker)

    if not clicker and not clicker:is_player() then
        return
    end
    if not self then
        return
    end
    if not self.yl_speak_up or not self.yl_speak_up.id then
        return
    end

    local npc_id = self.yl_speak_up.id
    local n_id = "n_" .. npc_id

    -- remember whom the npc belongs to (as long as we still have self.owner available for easy access)
    yl_speak_up.npc_owner[ n_id ] = self.owner

    local pname = clicker:get_player_name()
    if not self.yl_speak_up or not self.yl_speak_up.talk or self.yl_speak_up.talk~=true then

	-- show a formspec to other players that this NPC is busy
        if(not(yl_speak_up.may_edit_npc(clicker, n_id))) then
             -- show a formspec so that the player knows that he may come back later
             yl_speak_up.show_fs(player, "msg", {input_to = "yl_spaek_up:ignore", formspec =
		"size[6,2]"..
		"label[1.2,0.0;"..minetest.formspec_escape((self.yl_speak_up.npc_name or "This NPC")..
			" [muted]").."]"..
		"label[0.2,0.5;Sorry! I'm currently busy learning new things.]"..
		"label[0.2,1.0;Please come back later.]"..
		"button_exit[2.5,1.5;1,0.9;ok;Ok]"})
             return
        end
        -- allow the owner to edit (and subsequently unmute) the npc
	minetest.chat_send_player(pname, "This NPC is muted. It will only talk to you.")
    end

    yl_speak_up.speak_to[pname] = {}
    yl_speak_up.speak_to[pname].n_id = n_id -- Memorize which player talks to which NPC
    yl_speak_up.speak_to[pname].textures = self.yl_speak_up.textures
    yl_speak_up.speak_to[pname].option_index = 1
    -- the object itself may be needed in load_dialog for adding generic dialogs
    yl_speak_up.speak_to[pname].obj = self.object
    -- Load the dialog and see what we can do with it
    -- this inculdes generic dialog parts;
    -- make sure this is never true in edit mode (because in edit mode we want to
    --    edit this particular NPC without generic parts)
    local player = clicker
    if(yl_speak_up.edit_mode[pname] == n_id) then
	player = nil
    end
    yl_speak_up.speak_to[pname].dialog = yl_speak_up.load_dialog(n_id, clicker)

    -- is this player explicitly allowed to edit this npc?
    if(yl_speak_up.speak_to[pname].dialog
      and yl_speak_up.speak_to[pname].dialog.n_may_edit
      and yl_speak_up.speak_to[pname].dialog.n_may_edit[pname]
      and minetest.check_player_privs(clicker, {npc_talk_owner=true})) then
	yl_speak_up.speak_to[pname].may_edit_this_npc = true
    end

    yl_speak_up.show_fs(clicker, "talk", {n_id = n_id})

    local dialog = yl_speak_up.speak_to[pname].dialog
    if(not(dialog.trades)) then
       dialog.trades = {}
    end
end


-- mute the npc; either via the appropriate staff or via talking to him
yl_speak_up.set_muted = function(p_name, obj, set_muted)
	if(not(obj)) then
		return
	end
	local luaentity = obj:get_luaentity()
	if(not(luaentity)) then
		return
	end
	local npc = luaentity.yl_speak_up.id
	local npc_name = luaentity.yl_speak_up.npc_name
	-- fallback
	if(not(npc_name)) then
		npc_name = npc
	end
	if(set_muted and luaentity.yl_speak_up.talk) then
		-- the npc is willing to talk
		luaentity.yl_speak_up.talk = false
		yl_speak_up.update_nametag(luaentity)

		minetest.chat_send_player(p_name,"NPC with ID "..npc.." will shut up at pos "..
			minetest.pos_to_string(obj:get_pos(),0).." on command of "..p_name)
		minetest.log("action","[MOD] yl_speak_up: NPC with ID n_"..npc..
			" will shut up at pos "..minetest.pos_to_string(obj:get_pos(),0)..
			" on command of "..p_name)
	elseif(not(set_muted) and not(luaentity.yl_speak_up.talk)) then
		-- mute the npc
		luaentity.yl_speak_up.talk = true
		yl_speak_up.update_nametag(luaentity)

		minetest.chat_send_player(p_name,"NPC with ID "..npc.." will resume speech at pos "..
			minetest.pos_to_string(obj:get_pos(),0).." on command of "..p_name)
		minetest.log("action","[MOD] yl_speak_up: NPC with ID n_"..npc..
			" will resume speech at pos "..minetest.pos_to_string(obj:get_pos(),0)..
			" on command of "..p_name)
	end
end

-- has the player the right privs?
-- this is used for the "I am your master" talk based configuration; *NOT* for the staffs!
yl_speak_up.may_edit_npc = function(player, n_id)
	if(not(player)) then
		return false
	end
	local pname = player:get_player_name()
	-- is the player allowed to edit this npc?
	return ((yl_speak_up.npc_owner[ n_id ] == pname
	  and minetest.check_player_privs(player, {npc_talk_owner=true}))
	  or minetest.check_player_privs(player, {npc_talk_master=true})
	  or minetest.check_player_privs(player, {npc_master=true})
	  or (yl_speak_up.speak_to[pname]
	  and yl_speak_up.speak_to[pname].may_edit_this_npc))
end


-- log changes done by players or admins to NPCs
yl_speak_up.log_change = function(pname, n_id, text)
	-- make sure all variables are defined
	if(not(pname)) then
		pname = "- unkown player -"
	end
	if(not(n_id)) then
		n_id = "- unknown NPC -"
	end
	if(not(text)) then
		text = "- no text given -"
	end
	-- we don't want newlines in the texts
	text = string.gsub(text, "\n", "\\n")

	local log_text = "<"..tostring(n_id).."> ["..tostring(pname).."]: "..text
	-- log in general logfile
	minetest.log("yl_speak_up "..log_text)
	-- log with timestamp
	local log_text = tostring(os.time())..log_text
	-- TODO: log in a file for each npc and show it on demand?
end