-- supabase/migrations/20260709000003_incidents.sql
CREATE TYPE incident_type AS ENUM (
  'injury', 'near_miss', 'hazard', 'asset_damage', 'environmental', 'security', 'fire'
);

CREATE TYPE incident_status AS ENUM (
  'reported', 'triaged', 'investigating', 'capa_pending', 'verification', 'closed'
);

CREATE TYPE medical_status AS ENUM (
  'none', 'first_aid', 'medical_treatment', 'lti'
);

CREATE TABLE incidents (
  id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  reference_no    TEXT UNIQUE,
  incident_type   incident_type NOT NULL,
  site_id         UUID NOT NULL REFERENCES sites(id),
  zone_id         UUID REFERENCES zones(id),
  reported_by     UUID NOT NULL REFERENCES users(id),
  reported_at     TIMESTAMPTZ NOT NULL DEFAULT now(),
  description     TEXT NOT NULL,
  severity        SMALLINT CHECK (severity BETWEEN 1 AND 5),
  status          incident_status NOT NULL DEFAULT 'reported',
  injury_involved BOOLEAN NOT NULL DEFAULT false,
  asset_involved  BOOLEAN NOT NULL DEFAULT false,
  medical_status  medical_status,
  lost_days       INT CHECK (lost_days >= 0),
  closed_at       TIMESTAMPTZ,
  created_at      TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Auto-generate reference_no: SITECODE-YYYYMM-#### (e.g. SCW1-202607-0001)
CREATE OR REPLACE FUNCTION public.generate_incident_reference()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
DECLARE
  v_site_code TEXT;
  v_month     TEXT;
  v_seq       INT;
BEGIN
  SELECT UPPER(REGEXP_REPLACE(SUBSTRING(name, 1, 6), '[^A-Za-z0-9]', '', 'g'))
  INTO v_site_code
  FROM sites
  WHERE id = NEW.site_id;

  v_month := TO_CHAR(NEW.reported_at, 'YYYYMM');

  SELECT COUNT(*) + 1
  INTO v_seq
  FROM incidents
  WHERE site_id = NEW.site_id
    AND TO_CHAR(reported_at, 'YYYYMM') = v_month;

  NEW.reference_no := v_site_code || '-' || v_month || '-' || LPAD(v_seq::TEXT, 4, '0');
  RETURN NEW;
END;
$$;

CREATE TRIGGER set_incident_reference
  BEFORE INSERT ON incidents
  FOR EACH ROW
  WHEN (NEW.reference_no IS NULL)
  EXECUTE FUNCTION public.generate_incident_reference();

CREATE INDEX incidents_site_id_idx   ON incidents(site_id);
CREATE INDEX incidents_reported_by_idx ON incidents(reported_by);
CREATE INDEX incidents_status_idx    ON incidents(status);