defmodule Dash do
  def conn(call) do
  {:ok, pid} = Postgrex.start_link(
    hostname: call.db("node"),
    username: call.db("user"),
    password: call.db("pass"),
    database: call.db("name"),
  ); pid
  end

  def pull(call) do
    call |> conn |> Postgrex.query!("""
    SELECT
      n.nspname as "Schema",
      c.relname as "Name",
      CASE c.relkind WHEN 'r' THEN 'table' WHEN 'v' THEN 'view' WHEN 'm' THEN 'materialized view' WHEN 'i' THEN 'index' WHEN 'S' THEN 'sequence' WHEN 't' THEN 'TOAST table' WHEN 'f' THEN 'foreign table' WHEN 'p' THEN 'partitioned table' WHEN 'I' THEN 'partitioned index' END as "Type",
      pg_catalog.pg_get_userbyid(c.relowner) as "Owner",
      CASE c.relpersistence WHEN 'p' THEN 'permanent' WHEN 't' THEN 'temporary' WHEN 'u' THEN 'unlogged' END as "Persistence",
      am.amname as "Access method",
      pg_catalog.pg_size_pretty(pg_catalog.pg_table_size(c.oid)) as "Size",
      pg_catalog.obj_description(c.oid, 'pg_class') as "Description"
    FROM pg_catalog.pg_class c
         LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
         LEFT JOIN pg_catalog.pg_am am ON am.oid = c.relam
    WHERE c.relkind IN ('r','p','v','m','S','f','')
          AND n.nspname <> 'pg_catalog'
          AND n.nspname !~ '^pg_toast'
          AND n.nspname <> 'information_schema'
      AND pg_catalog.pg_table_is_visible(c.oid)
    ORDER BY 1,2
    """)
  end

  def read(call) do
    call |> pull |> Map.get(:rows)
    |> Enum.map(fn [_, name | _] -> name end)
  end
end