(* Implement subcommands for listing and adding tags. *)

open CalendarLib

open Todo_types
open Todo_utils
open Todo_tag_utils

open Printf

let cmd_tag_list dbh anon_params =
  if anon_params <> [] then
    error "extra parameters to 'tag-list' subcommand";

  (* Used tags. *)
  let rows = PGSQL(dbh) "
       select tags.name, tags.colour, tasks.id
         from tags_tasks, tags, tasks
        where tags_tasks.tagid = tags.id
          and tags_tasks.taskid = tasks.id
     order by tags.name, tasks.id" in
  if rows <> [] then printf "Tags used:\n";
  let prev = ref None in
  List.iter (
    fun (name, colour, taskid) ->
      let cur = name, colour in
      (match !prev with
      | None -> printf "    %s used by" (string_of_tag name colour)
      | Some prev when prev <> cur ->
         printf "\n    %s used by" (string_of_tag name colour)
      | Some _ -> ()
      );
      prev := Some cur;
      printf " #%ld" taskid
  ) rows;
  if !prev <> None then printf "\n";

  (* Unused tags. *)
  let rows = PGSQL(dbh) "
       select tags.name, tags.colour
         from tags
        where not exists (select 1 from tags_tasks where tagid = tags.id)
     order by tags.name" in
  if rows <> [] then printf "Tags not used (delete with 'todo tag-del'):\n";
  List.iter (
    fun (name, colour) ->
      printf "    %s\n" (string_of_tag name colour)
  ) rows

let cmd_tag dbh anon_params tag_del =
  let id, tag_add =
    match anon_params with
    | id :: rest -> Int32.of_string id, rest
    | _ -> error "incorrect parameters to 'tag' subcommand" in
  if anon_params = [] && tag_del = [] then
    error "no tags to add or delete from this task";

  (* Map the tag_add and tag_del names to tag IDs. *)
  let tag_add =
    if tag_add <> [] then
      PGSQL(dbh) "select id from tags where name in $@tag_add"
    else [] in
  let tag_del =
    if tag_del <> [] then
      PGSQL(dbh) "select id from tags where name in $@tag_del"
    else [] in

  PGOCaml.begin_work dbh;

  if tag_del <> [] then
    PGSQL(dbh) "delete from tags_tasks
                 where taskid = $id and tagid in $@tag_del";

  List.iter (
    fun tag ->
      PGSQL(dbh) "insert into tags_tasks (taskid, tagid) 
                                  values ($id, $tag)"
  ) tag_add;

  PGOCaml.commit dbh

let cmd_tag_add dbh anon_params =
  let name, colour =
    match anon_params with
    | [name; colour] -> name, colour
    | _ -> error "incorrect parameters to 'tag-add' subcommand" in

  PGOCaml.begin_work dbh;

  PGSQL(dbh) "insert into tags (name, colour) values ($name, $colour)";

  PGOCaml.commit dbh

let cmd_tag_del dbh anon_params =
  let name =
    match anon_params with
    | [name] -> name
    | _ -> error "incorrect parameters to 'tag-del' subcommand" in

  PGOCaml.begin_work dbh;

  PGSQL(dbh) "delete from tags where name = $name";

  PGOCaml.commit dbh

let cmd_tag_colour dbh anon_params =
  let name, colour =
    match anon_params with
    | [name; colour] -> name, colour
    | _ -> error "incorrect parameters to 'tag-colour' subcommand" in

  PGOCaml.begin_work dbh;

  PGSQL(dbh) "update tags set colour = $colour where name = $name";

  PGOCaml.commit dbh