local Luan = require "luan:Luan.luan"
local error = Luan.error
local ipairs = Luan.ipairs or error()
local Number = require "luan:Number.luan"
local long = Number.long or error()
local Time = require "luan:Time.luan"
local time_now = Time.now or error()
local Html = require "luan:Html.luan"
local html_encode = Html.encode or error()
local Db = require "site:/lib/Db.luan"
local run_in_transaction = Db.run_in_transaction or error()
local Ai_chat = require "site:/lib/ai/claude/Ai_chat.luan"
local languages = require "site:/lib/languages.luan"
local Utils = require "site:/lib/Utils.luan"
local get_first = Utils.get_first or error()
local Course = require "site:/lib/Course.luan"
local get_course_by_id = Course.get_by_id or error()
local Shared = require "site:/lib/Shared.luan"
local voices = Shared.voices or error()


local Chat = {}

local function from_doc(doc)
	doc.type == "chat" or error "wrong type"
	return Chat.new {
		id = doc.id
		user_id = doc.chat_user_id
		updated = doc.chat_updated
		course_id = doc.course_id
		name = doc.name
		ai_thread = doc.ai_thread
		language = doc.language
		language_region = doc.language_region
		voice = doc.voice
	}
end

local function to_doc(chat)
	return {
		type = "chat"
		id = chat.id
		chat_user_id = long(chat.user_id)
		chat_updated = long(chat.updated)
		course_id = long(chat.course_id)
		name = chat.name or error()
		ai_thread = chat.ai_thread
		language = chat.language or error()
		language_region = chat.language_region or error()
		voice = chat.voice or error()
	}
end

local function first_region(language)
	return get_first(languages[language].regions)
end

function Chat.new(chat)
	chat.updated = chat.updated or time_now()
	chat.language_region = chat.language_region or first_region(chat.language)
	chat.voice = chat.voice or voices[1].code

	function chat.save()
		local doc = to_doc(chat)
		Db.save(doc)
		chat.id = doc.id
	end

	function chat.reload()
		return Chat.get_by_id(chat.id) or error(chat.id)
	end

	function chat.delete()
		Db.delete("id:"..chat.id)
	end

	function chat.info()
		return {
			id = chat.id
			language_region = chat.language_region
			voice = chat.voice
			name = chat.name
		}
	end

	function chat.name_html()
		return html_encode(chat.name)
	end

	function chat.init_ai()  -- return if added message
		if chat.ai_thread ~= nil then
			return false
		end
		local course = get_course_by_id(chat.course_id) or error()
		local ai_first_message = course.ai_first_message
		local ai_thread = Ai_chat.ask_first(course.ai_system_prompt,ai_first_message)
		run_in_transaction( function()
			chat = chat.reload()
			chat.ai_thread = ai_thread
			chat.save()
		end )
		return ai_first_message ~= nil
	end

	function chat.output_system_prompt()
		Ai_chat.output_system_prompt(chat.ai_thread)
	end

	function chat.output_messages_html()
		Ai_chat.output_messages_html(chat.ai_thread)
	end

	function chat.ask(input)
		local old_thread = chat.ai_thread
		local ai_thread = Ai_chat.ask_more(old_thread,input)
		run_in_transaction( function()
			chat = chat.reload()
			chat.ai_thread = ai_thread
			chat.save()
		end )
		return `Ai_chat.output_messages_html(ai_thread,old_thread)`
	end

	function chat.language_name()
		return languages[chat.language].name
	end

	return chat
end

function Chat.search(query,sort,rows)
	rows = rows or 1000000
	local chats = {}
	local docs = Db.search(query,1,rows,{sort=sort})
	for _, doc in ipairs(docs) do
		chats[#chats+1] = from_doc(doc)
	end
	return chats
end

function Chat.get_by_id(id)
	local doc = Db.get_document("id:"..id)
	return doc and doc.type=="chat" and from_doc(doc) or nil
end

return Chat