lock = require "resty.lock"

import Tags, Tracks from require "models"
import escape_literal from require "lapis.db"

next_id = (id=0) ->
  next_tag = Tags\select "WHERE id > ? ORDER BY id ASC LIMIT 1", id
  unless next_tag
    next_tag = Tags\select "WHERE id > '0' ORDER BY id ASC LIMIT 1"
  if next_tag
    return next_tag[1].id

update_tag_counts = (premature, tag_id) ->
  if premature return

  thread_lock = lock\new "worker", { timeout: 0, exptime: 2 }
  if thread_lock\lock "update_tag_counts.thread"
    time_lock = lock\new "worker", { exptime: 2 }
    if time_lock\lock "update_tag_counts.time"

      if tag_id
        if tag = Tags\find id: tag_id
          tag_pattern = escape_literal tag.name
          tag_pattern = "'% #{tag_pattern\sub 2, -2} %'"
          count = Tracks\count "tags LIKE #{tag_pattern}"
          tag\update(:count)

      tag_id = next_id(tag_id) or tag_id
      thread_lock\unlock!

  ngx.timer.at(2, update_tag_counts, tag_id)

ngx.timer.at(0, update_tag_counts)