-- Migration 036: Transceiver equivalences for competitor_verified matching
-- Stores semantic equivalences between Flexoptix SKUs and competitor products
-- matched by technical specs (form_factor + speed + reach + standard + fiber_type)

CREATE TABLE IF NOT EXISTS transceiver_equivalences (
  id               UUID    DEFAULT gen_random_uuid() PRIMARY KEY,
  flexoptix_id     UUID    NOT NULL REFERENCES transceivers(id) ON DELETE CASCADE,
  competitor_id    UUID    NOT NULL REFERENCES transceivers(id) ON DELETE CASCADE,
  confidence       DECIMAL(4,3) NOT NULL CHECK (confidence BETWEEN 0 AND 1),
  match_basis      TEXT[]  NOT NULL DEFAULT '{}',   -- ['standard_name','form_factor','speed_gbps','fiber_type','reach']
  match_notes      TEXT,
  status           VARCHAR(20) NOT NULL DEFAULT 'pending'
                     CHECK (status IN ('pending','approved','rejected','auto_approved')),
  reviewed_by      VARCHAR(200),
  reviewed_at      TIMESTAMPTZ,
  reject_reason    TEXT,
  created_at       TIMESTAMPTZ DEFAULT NOW(),
  updated_at       TIMESTAMPTZ DEFAULT NOW(),
  UNIQUE (flexoptix_id, competitor_id)
);

CREATE INDEX IF NOT EXISTS idx_eq_flexoptix   ON transceiver_equivalences (flexoptix_id);
CREATE INDEX IF NOT EXISTS idx_eq_competitor  ON transceiver_equivalences (competitor_id);
CREATE INDEX IF NOT EXISTS idx_eq_status      ON transceiver_equivalences (status, confidence DESC);
CREATE INDEX IF NOT EXISTS idx_eq_pending     ON transceiver_equivalences (flexoptix_id) WHERE status = 'pending';

-- Auto-update updated_at
CREATE OR REPLACE FUNCTION update_equivalences_updated_at()
RETURNS TRIGGER AS $$
BEGIN
  NEW.updated_at = NOW();
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

DROP TRIGGER IF EXISTS trg_eq_updated_at ON transceiver_equivalences;
CREATE TRIGGER trg_eq_updated_at
  BEFORE UPDATE ON transceiver_equivalences
  FOR EACH ROW EXECUTE FUNCTION update_equivalences_updated_at();

COMMENT ON TABLE transceiver_equivalences IS
  'Semantic equivalences between Flexoptix SKUs and competitor products, '
  'matched by technical specification overlap. Used to set competitor_verified=true '
  'on Flexoptix transceivers that have no exact SKU match at competitors.';