-- 01_fuel_schema.sql — fleetfuel · WhatsApp fuel-record store (raw-jsonb-first)
-- ─────────────────────────────────────────────────────────────────────────────
-- The `fuel` schema: one raw-jsonb row per fuel record (the source PK `id` + the
-- full record as `raw`), plus DB-derived NORMALIZED columns the trigger fills from
-- `raw`. The feed is WhatsApp fuel-update messages (n8n CDC of the client's
-- `logistics_department.fuel_records`), which is messy — plate spacing, fuel-type
-- typos, ~30 department spellings — so the normalizers below are the single source
-- of truth, kept in the DB so reads never re-implement them.
--
--   fuel.records        id + raw + derived (plate, liters, amount, fuel_type,
--                       department, odometer, deleted_at, …)
--   fuel.ingest_state   CDC watermark for import_fuel.py --changes
--   reporting.v_fuel_fills       read view (joins devices by normalized plate)
--   reporting.v_fuel_efficiency  per-vehicle km/litre from odometer deltas
--
-- Lives in the shared `tracksolid_db` so the existing dashboard_api and the
-- FleetOps SPA keep working. Idempotent: safe on a fresh DB and re-appliable live.
-- ─────────────────────────────────────────────────────────────────────────────

CREATE SCHEMA IF NOT EXISTS fuel;
CREATE SCHEMA IF NOT EXISTS reporting;   -- shared read layer (the views live here for dashboard_api)

-- ── safe casts (bad WhatsApp values -> NULL, never error) ────────────────────
CREATE OR REPLACE FUNCTION fuel.to_num(p text)
 RETURNS numeric LANGUAGE plpgsql IMMUTABLE AS $fn$
BEGIN
  RETURN NULLIF(btrim(p), '')::numeric;
EXCEPTION WHEN others THEN
  RETURN NULL;
END $fn$;

CREATE OR REPLACE FUNCTION fuel.to_ts(p text)
 RETURNS timestamptz LANGUAGE plpgsql IMMUTABLE AS $fn$
BEGIN
  RETURN NULLIF(btrim(p), '')::timestamptz;
EXCEPTION WHEN others THEN
  RETURN NULL;
END $fn$;

-- ── normalizers (the single source of truth for the messy feed) ──────────────
-- Plate: upper, strip every non-alphanumeric ('KCA 542Q' -> 'KCA542Q'); drop junk
-- placeholders ('ANY VEH', 'NA', …) so they don't pollute the join.
CREATE OR REPLACE FUNCTION fuel.norm_plate(p text)
 RETURNS text LANGUAGE sql IMMUTABLE PARALLEL SAFE AS $fn$
  SELECT CASE
    WHEN upper(regexp_replace(coalesce(p, ''), '[^A-Za-z0-9]', '', 'g'))
         IN ('', 'ANYVEH', 'NA', 'NONE', 'NIL', 'NULL') THEN NULL
    ELSE NULLIF(upper(regexp_replace(p, '[^A-Za-z0-9]', '', 'g')), '')
  END
$fn$;

-- Fuel type: collapse the typo zoo into PETROL / DIESEL / VPOWER / OTHER / NULL.
CREATE OR REPLACE FUNCTION fuel.canon_fuel_type(p text)
 RETURNS text LANGUAGE sql IMMUTABLE PARALLEL SAFE AS $fn$
  WITH c AS (SELECT NULLIF(upper(regexp_replace(coalesce(p, ''), '[^A-Za-z]', '', 'g')), '') AS v)
  SELECT CASE
    WHEN v IS NULL          THEN NULL
    WHEN v LIKE '%VPOWER%'  THEN 'VPOWER'
    WHEN v LIKE '%PET%'     THEN 'PETROL'   -- PETROL, PETRO, PETROLI, /PETROL
    WHEN v LIKE 'DI%'       THEN 'DIESEL'   -- DIESEL, DISEL, DISIEL, DISEIL, DIRSEL
    ELSE 'OTHER'
  END FROM c
$fn$;

-- Department: upper, punctuation -> space, collapse, then map known variants.
CREATE OR REPLACE FUNCTION fuel.canon_department(p text)
 RETURNS text LANGUAGE sql IMMUTABLE PARALLEL SAFE AS $fn$
  WITH c AS (SELECT NULLIF(btrim(regexp_replace(upper(coalesce(p, '')), '[^A-Z0-9]+', ' ', 'g')), '') AS v)
  SELECT CASE
    WHEN v IS NULL                                   THEN NULL
    WHEN v LIKE '%OSP%' AND v LIKE '%PATROL%'         THEN 'OSP PATROL'
    WHEN v LIKE 'ROLL%OUT' OR v IN ('ROLLOUT','ROLOUT') THEN 'ROLLOUT'
    WHEN v LIKE 'ISP%'                                THEN 'ISP'
    WHEN v LIKE 'PLANNING%'                           THEN 'PLANNING'
    WHEN v LIKE 'OSP%'                                THEN 'OSP'
    WHEN v LIKE 'FDS%'                                THEN 'FDS'
    WHEN v LIKE 'DELIVER%'                            THEN 'DELIVERIES'
    WHEN v LIKE 'HUAWEI%'                             THEN 'HUAWEI'
    WHEN v LIKE 'AIRTEL%'                             THEN 'AIRTEL'
    WHEN v LIKE 'REGION%'                             THEN 'REGIONAL'
    WHEN v LIKE 'FTTH%'                               THEN 'FTTH'
    WHEN v LIKE 'QEHS%'                               THEN 'QEHS'
    WHEN v LIKE 'GENERAL%'                            THEN 'GENERAL'
    WHEN v LIKE 'LOGISTIC%'                           THEN 'LOGISTICS'
    ELSE v
  END FROM c
$fn$;

-- ── records: raw-jsonb-first + trigger-derived normalized columns ────────────
CREATE TABLE IF NOT EXISTS fuel.records (
  id                  bigint PRIMARY KEY,
  raw                 jsonb NOT NULL,
  record_datetime     timestamptz,
  car_raw             text,
  plate               text,
  liters              numeric,
  amount              numeric,
  fuel_type           text,
  fuel_type_raw       text,
  department          text,
  driver              text,
  odometer            numeric,
  deleted_at          timestamptz,
  message_fingerprint text,
  ingested_at         timestamptz NOT NULL DEFAULT now(),
  updated_at          timestamptz NOT NULL DEFAULT now()
);

-- Derive every normalized column from `raw` on write — the loader only supplies (id, raw).
CREATE OR REPLACE FUNCTION fuel.tg_records_derive()
 RETURNS trigger LANGUAGE plpgsql AS $fn$
BEGIN
  NEW.record_datetime     := fuel.to_ts(NEW.raw->>'record_datetime');
  NEW.car_raw             := NEW.raw->>'car';
  NEW.plate               := fuel.norm_plate(NEW.raw->>'car');
  NEW.liters              := fuel.to_num(NEW.raw->>'liters');
  NEW.amount              := fuel.to_num(NEW.raw->>'amount');
  NEW.fuel_type           := fuel.canon_fuel_type(NEW.raw->>'fuel_type');
  NEW.fuel_type_raw       := NEW.raw->>'fuel_type';
  NEW.department          := fuel.canon_department(NEW.raw->>'department');
  NEW.driver              := NULLIF(btrim(NEW.raw->>'driver'), '');
  NEW.odometer            := fuel.to_num(NEW.raw->>'odometer');
  NEW.deleted_at          := fuel.to_ts(NEW.raw->>'deleted_at');
  NEW.message_fingerprint := NEW.raw->>'message_fingerprint';
  NEW.updated_at          := now();
  RETURN NEW;
END $fn$;

DROP TRIGGER IF EXISTS trg_records_derive ON fuel.records;
CREATE TRIGGER trg_records_derive BEFORE INSERT OR UPDATE ON fuel.records
  FOR EACH ROW EXECUTE FUNCTION fuel.tg_records_derive();

CREATE INDEX IF NOT EXISTS ix_fuel_records_plate    ON fuel.records (plate);
CREATE INDEX IF NOT EXISTS ix_fuel_records_datetime ON fuel.records (record_datetime);
CREATE INDEX IF NOT EXISTS ix_fuel_records_dept     ON fuel.records (department);
CREATE INDEX IF NOT EXISTS ix_fuel_records_live     ON fuel.records (record_datetime) WHERE deleted_at IS NULL;

-- ── CDC watermark for import_fuel.py --changes ───────────────────────────────
CREATE TABLE IF NOT EXISTS fuel.ingest_state (
  key        text PRIMARY KEY,
  last_key   text,
  updated_at timestamptz NOT NULL DEFAULT now()
);

-- ── read view: live fills joined to the fleet by normalized plate ────────────
-- Joins devices so the Fuel Log tab reuses the same dims as the rest of FleetOps
-- (cost_centre / assigned_city / assigned_driver / vehicle_number — the columns
-- dashboard_api's _dim_filters expects). Keeps the fuel-native `department` and
-- `driver` (from the WhatsApp message) for fuel-specific filtering. Soft-deleted
-- rows are excluded here. Encapsulating the devices join means the read-only
-- staging role only needs SELECT on this view, not on tracksolid.devices.
CREATE OR REPLACE VIEW reporting.v_fuel_fills AS
 SELECT r.id,
        r.record_datetime,
        r.record_datetime::date AS fuel_date,
        r.plate,
        d.vehicle_number,
        d.cost_centre,
        d.assigned_city,
        d.driver_name           AS assigned_driver,
        d.imei,
        r.department,
        r.driver,
        r.liters,
        r.amount,
        r.fuel_type,
        r.odometer
   FROM fuel.records r
   LEFT JOIN tracksolid.devices d ON fuel.norm_plate(d.vehicle_number) = r.plate
  WHERE r.deleted_at IS NULL;

-- ── per-vehicle fuel efficiency: km/litre from consecutive odometer readings ──
-- Defensive: only positive, plausible (<5000 km) odometer deltas yield km/litre.
CREATE OR REPLACE VIEW reporting.v_fuel_efficiency AS
 WITH seq AS (
   SELECT id, plate, vehicle_number, cost_centre, assigned_city,
          record_datetime, fuel_date, odometer, liters, amount, fuel_type,
          odometer - lag(odometer) OVER (PARTITION BY plate ORDER BY record_datetime, id) AS km_since_last
     FROM reporting.v_fuel_fills
    WHERE plate IS NOT NULL AND odometer IS NOT NULL AND odometer > 0
 )
 SELECT seq.*,
        CASE WHEN liters > 0 AND km_since_last > 0 AND km_since_last < 5000
             THEN round(km_since_last / liters, 2)
        END AS km_per_litre
   FROM seq;

-- ── read-only grant (staging dashboard_api connects as grafana_ro) ───────────
-- Mirrors migrations/18_grant_reporting_ro.sql in the tracksolid repo. Guarded +
-- idempotent. Only the reporting views are exposed (not fuel.records) — the views
-- run with the owner's rights, so grafana_ro needs nothing on the base tables.
DO $grants$
BEGIN
  IF EXISTS (SELECT 1 FROM pg_roles WHERE rolname = 'grafana_ro') THEN
    GRANT USAGE ON SCHEMA reporting TO grafana_ro;
    GRANT SELECT ON reporting.v_fuel_fills, reporting.v_fuel_efficiency TO grafana_ro;
  END IF;
END $grants$;