let version = 0
type info_t = { version: int; id: string; title: string; people: string list; locations: string list }
type t = { info: info_t; fields: Msgpck.t; texts: Msgpck.t; peers: Msgpck.t }

let of_id id = Msgpck.of_string id
let to_id = Msgpck.to_string

let person p = Msgpck.String (Person.to_string p)
let persons ps = Msgpck.of_list @@ List.rev @@ Person.Set.fold (fun p a -> person p :: a) ps []

let str = Msgpck.of_string
let str_list ls = Msgpck.of_list @@ List.map str ls
let to_str_list x = List.map Msgpck.to_string (Msgpck.to_list x)

let of_set field t =
	List.rev @@ String_set.fold (fun s a -> Msgpck.String s :: a) (Text.set field t) []

let date = function "" -> Int32.zero | date -> Int32.of_int (Date.to_secs date)

let to_sec = function Msgpck.Int i -> Int32.of_int i | Msgpck.Uint32 i -> i | x -> Msgpck.to_uint32 x

let fields = Msgpck.(List [String "id"; String "time";  String "title"; String "authors"; String "topics"])
let to_fields fieldpack = List.map Msgpck.to_string (Msgpck.to_list fieldpack)

let to_info = function
	| Msgpck.List (v::id::n::a::ls::[]) ->
		let people = to_str_list a in
		let locations = to_str_list ls in
		Msgpck.({version = to_int v; id = to_string id; title = to_string n; people; locations})
	| _ -> invalid_arg "Pack header"

let of_info i = let open Msgpck in
	List [Int i.version; String i.id; String i.title; str_list i.people; str_list i.locations]

let of_text a t =
	let open Text in
	Msgpck.(List [
		of_id t.id; of_uint32 (date (Date.listing t.date));
		String t.title; persons t.authors; List (of_set "topics" t)
	]) :: a

let of_text_list l = Msgpck.List l

let pack p = Msgpck.List [of_info p.info; p.fields; p.texts; p.peers]
let string p = Bytes.to_string @@ Msgpck.Bytes.to_string @@ pack p

let unpack = function
	| Msgpck.List (i::fields::texts::[]) ->
		Ok { info = to_info i; fields; texts; peers = Msgpck.List [] }
	| Msgpck.List (i::fields::texts::peers::[]) ->
		Ok { info = to_info i; fields; texts; peers }
	| _ -> Error "format mismatch"

let of_string s = unpack @@ snd @@ Msgpck.StringBuf.read s

let list filename = try
	let texts_list = function
	| Msgpck.List (_info :: _fields :: [texts]) -> Msgpck.to_list texts
	| _ -> prerr_endline "malformed feed"; [] in
	let _pos, data = Msgpck.StringBuf.read @@ File_store.to_string filename in
	Ok (texts_list data)
	with Not_found -> Error "unspecified export dir"

let contains text = function
	| Msgpck.List (id::_time::title::_authors::_topics::[]) ->
		(match to_id id with
		 | "" -> prerr_endline ("Invalid id for " ^ Msgpck.to_string title); false
		 | id -> text.Text.id = id)
	| _ -> prerr_endline ("Invalid record pattern"); false

let numof_texts pack = List.length (Msgpck.to_list pack.texts)

let iteri fn pack =
	let of_pck i = function Msgpck.List (id::time::title::authors::topics::[]) ->
		let t = match time with Msgpck.Int i -> Int32.of_int i | Msgpck.Uint32 i -> i
			| x -> Msgpck.to_uint32 x in
		let id = to_id id in
		let title = Msgpck.to_string title in
		let topics = to_str_list topics in
		let authors = to_str_list authors in
		fn i id t title authors topics
	| _  -> prerr_endline ("\n\nInvalid record structure\n\n")
	in List.iteri of_pck (Msgpck.to_list pack.texts);

(*let pack_filename ?(filename="index.pck") archive =*)
(*	let dir = Store.KV.find "Export-Dir" archive.File_store.kv in (*raises Not_found*)*)
(*	dir ^ "/" ^ filename*)

(*let add archive records =*)
(*	let fname = pack_filename archive in*)
(*	let append published (t, _f) = if List.exists (contains t) published then published else to_pack published t in*)
(*	match list fname with Error e -> prerr_endline e | Ok published_list ->*)
(*		let header_pack = List.fold_left append published_list records in*)
(*		let archive = Msgpck.(List [*)
(*			Int 0; String archive.File_store.name; persons archive.people]) in*)
(*		File_store.file fname @@ Bytes.to_string*)
(*			@@ Msgpck.Bytes.to_string (List [archive; fields; Msgpck.List header_pack])*)