-- Databricks notebook source
-- =============================================================================
-- Purpose    : Build the flattened IMS NFC level 1-3 hierarchy.
-- Source     : dwd.dwd_ims_td_new_form_class
-- Target     : dwd.dwd_ims_nfc_hierarchy
-- Grain      : One row per hierarchy path rooted at NFC1_CODE; lower levels may be null.
-- Write mode : Full refresh (INSERT OVERWRITE).
-- Downstream : dwd.dwd_ims_td_pack_property, dws.dws_ims_td_nfc_cn
-- Notes      : Parent-code matching is preserved from the legacy script.
-- =============================================================================

INSERT OVERWRITE TABLE dwd.dwd_ims_nfc_hierarchy (
    NFC1_ID,
    NFC1_CODE,
    NFC1_DES,
    NFC2_ID,
    NFC2_CODE,
    NFC2_DES,
    NFC3_ID,
    NFC3_CODE,
    NFC3_DES
)
WITH new_form_class AS (
    SELECT
        newformclass_id,
        newformclass_code,
        newformclass_name,
        newformclass_level
    FROM dwd.dwd_ims_td_new_form_class
),
nfc_level_1 AS (
    SELECT
        newformclass_id AS nfc1_id,
        newformclass_code AS nfc1_code,
        newformclass_name AS nfc1_des
    FROM new_form_class
    WHERE newformclass_level = '1'
),
nfc_level_2 AS (
    SELECT
        newformclass_id AS nfc2_id,
        newformclass_code AS nfc2_code,
        newformclass_name AS nfc2_des
    FROM new_form_class
    WHERE newformclass_level = '2'
),
nfc_level_3 AS (
    SELECT
        newformclass_id AS nfc3_id,
        newformclass_code AS nfc3_code,
        newformclass_name AS nfc3_des
    FROM new_form_class
    WHERE newformclass_level = '3'
)
SELECT
    nfc_level_1.nfc1_id,
    nfc_level_1.nfc1_code,
    nfc_level_1.nfc1_des,
    nfc_level_2.nfc2_id,
    nfc_level_2.nfc2_code,
    nfc_level_2.nfc2_des,
    nfc_level_3.nfc3_id,
    nfc_level_3.nfc3_code,
    nfc_level_3.nfc3_des
FROM nfc_level_1
LEFT JOIN nfc_level_2
    ON nfc_level_1.nfc1_code = LEFT(nfc_level_2.nfc2_code, 1)
LEFT JOIN nfc_level_3
    ON nfc_level_2.nfc2_code = LEFT(nfc_level_3.nfc3_code, 2)
;