require 'sequel'

require_relative './models/post'
require_relative './models/thread'

RESULTS_PER_PAGE = 50

def search(params)
  query = params[:q].strip
  offset = (params[:page] - 1) * RESULTS_PER_PAGE
  username = params[:username].strip
  from_date = params[:from_date].strip
  to_date = params[:to_date].strip
  sort = params[:sort].strip
  exact_match = params[:exact_match].strip == "yes"

  errors = Array.new

  if from_date.empty?
    from_date = nil
  else
    if from_date.match(/\d{4}-\d{2}-\d{2}/)
      from_date = Date.parse(params[:from_date]) rescue errors << 'Invalid From Date'
    else
      errors << 'From Date must be in the format YYYY-MM-DD'
    end
  end

  if to_date.empty?
    to_date = nil
  else
    if to_date.match(/\d{4}-\d{2}-\d{2}/)
      to_date = Date.parse(params[:to_date]).next rescue errors << 'Invalid To Date'
    else
      errors << 'To Date must be in the format YYYY-MM-DD'
    end
  end

  if errors.empty? && !to_date.nil? && !from_date.nil? &&  to_date < from_date
    errors << 'To Date must be after From Date'
  end

  return {results: Array.new, errors: errors} unless errors.empty?

  results = case params[:type]
  when 'threads'
    search_threads(query, username, from_date, to_date, sort, offset, exact_match)
  when 'posts'
    search_posts(query, username, from_date, to_date, offset, exact_match)
  else
    Array.new
  end

  {results: results, errors: errors}
end

def search_threads(q, username, from_date, to_date, sort, offset, exact_match)
  sort = Sequel.desc(sort == 'post' ? :last_post_created_at : :created_at)
  query = VLV::Thread
    .select(Sequel.lit('threads.*, count(*) OVER() AS full_count'))
    .where(Sequel.lit("(LOWER(threads.creator) = LOWER(?) OR ? = '')", username, username))
    .where(Sequel.lit("created_at >= ? OR ? IS NULL", from_date, from_date))
    .where(Sequel.lit("created_at >= ? OR ? IS NULL", to_date, to_date))
    .order(sort)
    .limit(RESULTS_PER_PAGE)
    .offset(Sequel.lit('?', offset))

  if exact_match
    query.where(Sequel.ilike(:title, "%#{q}%"))
  else
    query.full_text_search(:title, Sequel.lit("websearch_to_tsquery(?)", q), tsquery: true, language: 'english')
  end
end

def search_posts(q, username, from_date, to_date, offset, exact_match)
  query = VLV::Post
    .select(Sequel.lit('posts.*, threads.title as thread_title, threads.remote_id as remote_thread_id, count(*) OVER() AS full_count'))
    .join(Sequel.lit('threads on posts.thread_id = threads.id'))
    .where(Sequel.lit("(LOWER(posts.creator) = LOWER(?) OR (? = ''))", username, username))
    .where(Sequel.lit("posts.created_at >= ? OR ? IS NULL", from_date, from_date))
    .where(Sequel.lit("posts.created_at >= ? OR ? IS NULL", to_date, to_date))
    .limit(RESULTS_PER_PAGE)
    .offset(Sequel.lit('?', offset))
    .order(Sequel.desc(Sequel.lit('posts.created_at')))

  if exact_match
    query.where(Sequel.ilike(:body, "%#{q}%"))
  else
    query.full_text_search(:tsv, Sequel.lit("websearch_to_tsquery(?)", q), {
      tsquery: true,
      tsvector: true,
      language: 'english'
    })
  end
end