CREATE OR ALTER FUNCTION pricing.single_price_call_fn (
    @bill   VARCHAR(100),
    @ship   VARCHAR(100),
    @part   VARCHAR(100),
    @stlc   VARCHAR(100),
    @v1ds   VARCHAR(100),
    @vol    NUMERIC(18,6)
)
RETURNS TABLE
AS
RETURN
(
    WITH queue AS (
        SELECT 
            @bill AS bill,
            @ship AS ship,
            @part AS part,
            @stlc AS stlc,
            @v1ds AS v1ds,
            @vol  AS vol
    ),
    enriched AS (
        SELECT
            q.*,
            CASE SUBSTRING(bc.cclass, 2, 3)
                WHEN 'DIS' THEN 
                    CASE SUBSTRING(sc.cclass, 2, 3)
                        WHEN 'DIS' THEN 'WHS'
                        ELSE 'DRP'
                    END
                ELSE 'DIR'
            END AS chan,
            CASE SUBSTRING(bc.cclass, 2, 3)
                WHEN 'DIR' THEN bc.tier
                ELSE ISNULL(sc.tier, bc.tier)
            END AS tier,
            CASE SUBSTRING(bc.cclass, 2, 3)
                WHEN 'DIS' THEN 
                    CASE SUBSTRING(sc.cclass, 2, 3)
                        WHEN 'DIS' THEN bc.dba
                        ELSE sc.dba
                    END
                ELSE q.bill
            END AS cust,
            i.mpck AS pltq
        FROM queue q
        LEFT JOIN rlarp.cust bc ON bc.code = q.bill
        LEFT JOIN rlarp.cust sc ON sc.code = q.ship
        LEFT JOIN CMSInterfaceIn.[CMS.CUSLG].itemm i ON i.item = q.part
    ),
    hist AS (
        SELECT TOP 1
            j.qty,
            j.price,
            j.odate,
            j.ordnum,
            j.quoten
        FROM pricing.lastprice lp
        OUTER APPLY OPENJSON(lp.part_stats) AS p
        OUTER APPLY OPENJSON(p.value)
            WITH (
                qty     NUMERIC(20,5),
                price   NUMERIC(20,5),
                odate   DATE,
                ordnum  INT,
                quoten  INT
            ) AS j
        INNER JOIN enriched e ON
            lp.customer = e.cust
            AND lp.mold = SUBSTRING(e.part,1,8)
        WHERE p.[key] COLLATE SQL_Latin1_General_CP1_CI_AS = e.part
        ORDER BY j.odate DESC
    ),
    hist_json AS (
        SELECT 
            CAST(ROUND(h.price, 5) AS NVARCHAR(50)) AS last_price,
            (
                SELECT qty, price, odate, ordnum, quoten
                FROM hist h
                FOR JSON PATH, WITHOUT_ARRAY_WRAPPER
            ) AS hist
        FROM hist h
    ),
    final AS (
        SELECT 
            e.part,
            tp.price,
            (
                SELECT 
                    'target price' AS [source],
                    tp.price AS [target_price],
                    CAST(hj.last_price AS NUMERIC(20,5)) AS [last_price],
                    FLOOR(e.vol / NULLIF(e.pltq, 0)) AS [calculated_pallets],
                    ROUND(e.vol / NULLIF(e.pltq, 0), 5) AS [exact_pallets],
                    CONCAT(tp.lower_bound, '-', ISNULL(CAST(tp.upper_bound AS VARCHAR), '∞')) AS [volume range],
                    e.cust AS [customer],
                    e.chan AS [channel],
                    e.tier AS [tier],
                    JSON_QUERY(tp.math) AS [target math],
                    JSON_QUERY(hj.hist) AS [price history]
                FOR JSON PATH, WITHOUT_ARRAY_WRAPPER
            ) AS expl
        FROM enriched e
        INNER JOIN pricing.target_prices tp ON
            e.stlc = tp.stlc
            AND e.v1ds = tp.ds
            AND e.chan = tp.chan
            AND e.tier = tp.tier
            AND FLOOR(e.vol / NULLIF(e.pltq, 0)) >= tp.lower_bound
            AND (
                tp.upper_bound IS NULL 
                OR FLOOR(e.vol / NULLIF(e.pltq, 0)) < tp.upper_bound
            )
        LEFT JOIN hist_json hj ON 1 = 1
    )
    SELECT price, expl FROM final
);