/*
====================================================================================
 Script: single_price_call.pg.sql
 Purpose: Single price call logic for a specific scenario (PostgreSQL)
 -----------------------------------------------------------------------------------
 Description:
   - Accepts a single pricing scenario (bill, ship, part, v1ds, vol)
   - Enriches with customer, channel, tier, pack quantity, price level, and part group
   - Looks up and applies target price, price history, list price, and guidance logic
   - Builds a JSON explanation and UI JSON for the scenario

 Inputs:
   - bill, ship, part, v1ds, vol (function arguments)
   - Reference tables: pricequote.target_prices, pricequote.lastpricedetail, pricequote.pricelist_ranged
   - Customer/item reference: rlarp.cust, CMS.CUSLG.itemm, CMS.CUSLG.IPRCBHC

 Outputs:
   - Returns a single enriched row with all pricing and explanation fields

 Key Business Logic:
   - Channel/tier/customer resolution based on bill/ship codes
   - Target price and math lookup by segment, channel, tier, and volume
   - Price history precedence and extraction via helper function
   - List price selection: lowest valid price for the scenario
   - Guidance logic: computed from target, last, and list prices

 Dependencies:
   - pricequote.guidance_logic (function)
   - pricequote.pick_last_price_from_hist (function)

 Notes:
   - Designed for single-row pricing queries (API or UI)
   - Assumes all referenced tables and functions exist
   - See also: matrix_guidance.pg.sql for batch/matrix logic
====================================================================================
*/

DROP FUNCTION pricequote.single_price_call(text,text,text,text,numeric);

CREATE OR REPLACE FUNCTION pricequote.single_price_call(
    _bill TEXT,
    _ship TEXT,
    _part TEXT,
    _v1ds TEXT,
    _vol NUMERIC
)
RETURNS TABLE (
    bill TEXT,
    ship TEXT,
    part TEXT,
    stlc TEXT,
    v1ds TEXT,
    vol NUMERIC,
    chan TEXT,
    cust TEXT,
    tier TEXT,
    pltq NUMERIC,
    plevel TEXT,
    partgroup TEXT,
    part_v1ds TEXT,
    v0ds TEXT,
    curstd_orig NUMERIC,
    futstd_orig NUMERIC,
    curstd NUMERIC,
    futstd NUMERIC,
    curstd_last NUMERIC,
    futstd_last NUMERIC,
    customized TEXT,
    last_premium NUMERIC,
    last_premium_method TEXT,
    last_price_norm NUMERIC,
    last_isdiff TEXT,
    last_v0ds TEXT,
    tprice_last NUMERIC,
    last_price NUMERIC,
    last_qty NUMERIC,
    last_dataseg TEXT,
    last_date DATE,
    last_order TEXT,
    last_quote TEXT,
    last_source TEXT,
    tprice NUMERIC,
    tmath JSONB,
    volume_range TEXT,
    listprice NUMERIC,
    listcode TEXT,
    listprice_eff NUMERIC,
    list_relevance TEXT,
    guidance_price NUMERIC,
    guidance_reason TEXT,
    expl JSONB,
    ui_json JSONB
) AS $$
DECLARE
    _pltq NUMERIC;
    _chan TEXT;
    _tier TEXT;
    _cust TEXT;
    _plevel TEXT;
    _partgroup TEXT;
    _stlc TEXT;
    _part_v1ds TEXT;
    _v0ds TEXT;
    _curstd_orig NUMERIC;
    _futstd_orig NUMERIC;
    _curstd NUMERIC;
    _futstd NUMERIC;
    _curstd_last NUMERIC;
    _futstd_last NUMERIC;
    _customized TEXT := '';
    _last_premium NUMERIC;
    _last_premium_method TEXT;
    _last_price_norm NUMERIC;
    _last_isdiff TEXT;
    _last_v0ds TEXT;
    _tprice_last NUMERIC;
    _tprice NUMERIC;
    _tmath JSONB;
    _volume_range TEXT;
    _list_price NUMERIC;
    _list_code TEXT;
    _listprice_eff NUMERIC;
    _list_relevance TEXT;
    _guidance_price NUMERIC;
    _guidance_reason TEXT;
    _hist JSONB := '{}'::jsonb;
    _last JSONB;
    _last_price NUMERIC;
    _last_qty NUMERIC;
    _last_dataseg TEXT;
    _last_date DATE;
    _last_order TEXT;
    _last_quote TEXT;
    _last_source TEXT;
    _expl JSONB := '{}'::jsonb;
    _ui_json JSONB := '{}'::jsonb;
BEGIN
    ------------------------------------------------------------------
    -- Step 1: Resolve customer metadata and part master data
    ------------------------------------------------------------------
    SELECT
        i.mpck,
        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,
        CASE SUBSTRING(bc.cclass, 2, 3)
            WHEN 'DIR' THEN bc.tier
            ELSE COALESCE(sc.tier, bc.tier)
        END,
        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 bc.dba
        END,
        CASE SUBSTRING(bc.cclass, 2, 3)
            WHEN 'DIS' THEN 
                CASE SUBSTRING(sc.cclass, 2, 3)
                    WHEN 'DIS' THEN sc.plevel
                    ELSE bc.plevel
                END
            ELSE bc.plevel
        END,
        i.partgroup,
        substring(_part,1,8),
        i.v1ds,
        CASE substring(_v1ds,4,1) WHEN 'B' THEN 'B' ELSE 'C' END || CASE substring(_v1ds,6,1) WHEN 'L' THEN 'L' WHEN 'P' THEN 'P' ELSE '' END,
        i.curstdus,
        i.futstdus
    INTO _pltq, _chan, _tier, _cust, _plevel, _partgroup, _stlc, _part_v1ds, _v0ds, _curstd_orig, _futstd_orig
    FROM rlarp.cust bc
    LEFT JOIN rlarp.cust sc ON sc.code = _ship
    LEFT JOIN "CMS.CUSLG".itemm i ON i.item = _part
    WHERE bc.code = _bill;

    -- Customized flag
    IF _part_v1ds IS NOT NULL AND _v1ds IS NOT NULL AND _part_v1ds <> _v1ds THEN
        _customized := 'Customized';
    END IF;

    ------------------------------------------------------------------
    -- Step 2: Target price logic (current and for last_dataseg)
    ------------------------------------------------------------------
    SELECT tp.price, to_json(tp.math), tp.vol::text
    INTO _tprice, _tmath, _volume_range
    FROM pricequote.target_prices tp
    WHERE tp.stlc = _stlc
      AND tp.ds = _v1ds
      AND tp.chan = _chan
      AND tp.tier = _tier
      AND FLOOR(_vol / NULLIF(_pltq, 0))::int <@ tp.vol;

    ------------------------------------------------------------------
    -- Step 3: Last sale/quote/volume/segment data
    ------------------------------------------------------------------
    SELECT lp.part_stats INTO _hist
    FROM pricequote.lastpricedetail lp
    WHERE lp.customer = _cust
      AND lp.partgroup = _partgroup;

    _last := pricequote.pick_last_price_from_hist(_hist, _v1ds);
    _last_price := (_last->>'price')::numeric;
    _last_qty := (_last->>'qty')::numeric;
    _last_dataseg := _last->>'datasegment';
    _last_date := (_last->>'odate')::date;
    _last_order := _last->>'ordnum';
    _last_quote := _last->>'quoten';
    _last_source := _last->>'source';

    -- last_v0ds logic
    _last_v0ds := 
        CASE substring(_last_dataseg,4,1) WHEN 'B' THEN 'B' ELSE 'C' END ||
        CASE substring(_last_dataseg,6,1) WHEN 'L' THEN 'L' WHEN 'P' THEN 'P' ELSE '' END;

    -- last_isdiff logic
    IF _last_dataseg IS NOT NULL AND _v1ds IS NOT NULL AND _last_dataseg <> _v1ds THEN
        _last_isdiff := 'Last Sale Diff Part';
    END IF;

    -- Target price for last_dataseg
    SELECT tp.price
    INTO _tprice_last
    FROM pricequote.target_prices tp
    WHERE tp.stlc = _stlc
      AND tp.ds = _last_dataseg
      AND tp.chan = _chan
      AND tp.tier = _tier
      AND FLOOR(_vol / NULLIF(_pltq, 0))::int <@ tp.vol;

    ------------------------------------------------------------------
    -- Step 4: Cost data for normalization
    ------------------------------------------------------------------
    -- Current/future standard for requested v1ds
    SELECT curstdus, futstdus INTO _curstd, _futstd
    FROM "CMS.CUSLG".itemm i
    WHERE i.item = _part AND i.v1ds = _v1ds;

    -- Current/future standard for last_dataseg
    SELECT curstdus, futstdus INTO _curstd_last, _futstd_last
    FROM "CMS.CUSLG".itemm i
    WHERE i.item = _part AND i.v1ds = _last_dataseg;

    ------------------------------------------------------------------
    -- Step 5: Normalize last price if needed
    ------------------------------------------------------------------
    IF _last_isdiff IS NOT NULL THEN
        IF _tprice_last IS NOT NULL AND _tprice IS NOT NULL AND _tprice_last <> 0 THEN
            _last_premium := _tprice / _tprice_last;
            _last_price_norm := ROUND(_last_price * (_tprice / _tprice_last), 5);
            _last_premium_method := 'Target Price Ratio';
        ELSIF _curstd_last IS NOT NULL AND _curstd IS NOT NULL AND _curstd_last <> 0 THEN
            _last_premium := _curstd / _curstd_last;
            _last_price_norm := ROUND(_last_price * (_curstd / _curstd_last), 5);
            _last_premium_method := 'Cost Ratio';
        ELSE
            _last_price_norm := _last_price;
            _last_premium_method := 'Unknown';
        END IF;
    ELSE
        _last_price_norm := _last_price;
    END IF;

    ------------------------------------------------------------------
    -- Step 6: List price logic
    ------------------------------------------------------------------
    SELECT pr.price::numeric(20,5), pr.jcplcd
    INTO _list_price, _list_code
    FROM "CMS.CUSLG".IPRCBHC i
    JOIN pricequote.pricelist_ranged pr
      ON pr.jcplcd = TRIM(i.jbplcd)
     AND pr.jcpart = _part
     AND _vol >= pr.vb_from
     AND (_vol < pr.vb_to OR pr.vb_to IS NULL)
    WHERE TRIM(i.jbplvl) = TRIM(_plevel)
      AND CURRENT_DATE BETWEEN i.jbfdat AND i.jbtdat
    ORDER BY pr.price ASC
    LIMIT 1;

    -- List price relevance
    IF _customized <> '' THEN
        _listprice_eff := NULL;
        _list_relevance := 'Ignore - Customized';
    ELSE
        _listprice_eff := _list_price;
        _list_relevance := '';
    END IF;

    ------------------------------------------------------------------
    -- Step 7: Compute guidance price and embed it
    ------------------------------------------------------------------
    SELECT gl.guidance_price, gl.guidance_reason
    INTO _guidance_price, _guidance_reason
    FROM pricequote.guidance_logic(_tprice, _last_price_norm, _listprice_eff, _last_date) gl;

    ------------------------------------------------------------------
    -- Step 8: Build explanation JSON
    ------------------------------------------------------------------
    _expl := jsonb_build_object(
        'last_price', _last_price,
        'last_qty', _last_qty,
        'last_dataseg', _last_dataseg,
        'last_v0ds', _last_v0ds,
        'last_source', _last_source,
        'last_date', _last_date,
        'last_order', _last_order,
        'last_quote', _last_quote,
        'last_isdiff', _last_isdiff,
        'tprice_last', _tprice_last,
        'target_price', _tprice,
        'target_math', _tmath,
        'calculated_pallets', FLOOR(_vol / NULLIF(_pltq, 0)),
        'exact_pallets', ROUND(_vol / NULLIF(_pltq, 0), 5),
        'customer', _cust,
        'channel', _chan,
        'tier', TRIM(_tier),
        'part_v1ds', _part_v1ds,
        'curstd_orig', _curstd_orig,
        'futstd_orig', _futstd_orig,
        'v0ds', _v0ds,
        'curstd', _curstd,
        'futstd', _futstd,
        'curstd_last', _curstd_last,
        'futstd_last', _futstd_last,
        'customized', _customized,
        'last_premium', _last_premium,
        'last_premium_method', _last_premium_method,
        'last_price_norm', _last_price_norm,
        'listcode', _list_code,
        'listprice', _list_price,
        'listprice_eff', _listprice_eff,
        'list_relevance', _list_relevance,
        'guidance_price', _guidance_price,
        'guidance_reason', _guidance_reason
    );

    ------------------------------------------------------------------
    -- Step 9: Build UI JSON (panels)
    ------------------------------------------------------------------
    _ui_json := jsonb_build_object(
        'details', jsonb_build_array(
            jsonb_build_object(
                'label', 'History',
                'details', jsonb_build_array(
                    jsonb_build_object(
                        'label', CASE WHEN _last_price IS NOT NULL THEN 'Last Sale: ' || _last_date ELSE 'No Recent' END,
                        'value', COALESCE(_last_price,0),
                        'type', 'currency',
                        'note', CASE WHEN _last_price IS NOT NULL THEN _last_source || 
                            CASE WHEN COALESCE(_last_order, '0') = '0' THEN ' Qt# ' || COALESCE(_last_quote, '') ELSE ' Ord# ' || COALESCE(_last_order, '') END
                            ELSE NULL END
                    )
                )
            ),
            jsonb_build_object(
                'label', 'List',
                'details', jsonb_build_array(
                    jsonb_build_object(
                        'label', 'List:' || COALESCE(_list_code, ''),
                        'value', _list_price,
                        'type', 'currency',
                        'note', _list_relevance
                    )
                )
            ),
            jsonb_build_object(
                'label', 'Target Support',
                'details', _tmath
            ),
            jsonb_build_object(
                'label', 'Guidance',
                'details', jsonb_build_array(
                    jsonb_build_object(
                        'label', 'Price',
                        'value', _guidance_price,
                        'type', 'currency',
                        'note', _guidance_reason
                    )
                )
            )
        ),
        'data', _expl
    );

    ------------------------------------------------------------------
    -- Final: Return row
    ------------------------------------------------------------------
    RETURN QUERY
    SELECT 
        _bill, _ship, _part, _stlc, _v1ds, _vol,
        _chan, _cust, _tier, _pltq, _plevel, _partgroup, _part_v1ds, _v0ds,
        _curstd_orig, _futstd_orig, _curstd, _futstd, _curstd_last, _futstd_last,
        _customized, _last_premium, _last_premium_method, _last_price_norm, _last_isdiff, _last_v0ds, _tprice_last,
        _last_price, _last_qty, _last_dataseg, _last_date, _last_order, _last_quote, _last_source,
        _tprice, _tmath, _volume_range,
        _list_price, _list_code, _listprice_eff, _list_relevance,
        _guidance_price, _guidance_reason,
        _expl, _ui_json;
END;
$$ LANGUAGE plpgsql;