-- ==========================================
-- CLUB DAGUERRE CAMERA DATABASE
-- Part 6: Triggers & Functions
-- ==========================================

-- ==========================================
-- FUNCTION: Update Denormalized Fields
-- ==========================================
CREATE OR REPLACE FUNCTION update_combo_denormalized()
RETURNS TRIGGER AS $$
BEGIN
  -- Get hierarchy IDs
  SELECT 
    hv.camera_model_id,
    cm.manufacturer_id
  INTO 
    NEW.camera_model_id,
    NEW.manufacturer_id
  FROM housing_variants hv
  JOIN camera_models cm ON hv.camera_model_id = cm.id
  WHERE hv.id = NEW.housing_variant_id;
  
  -- Generate Goergens ID
  SELECT 
    m.goergens_code || ' K ' || cm.goergens_model_number || ' ' || 
    hv.goergens_variant_letter || NEW.goergens_combo_number
  INTO NEW.goergens_full_id
  FROM housing_variants hv
  JOIN camera_models cm ON hv.camera_model_id = cm.id
  JOIN manufacturers m ON cm.manufacturer_id = m.id
  WHERE hv.id = NEW.housing_variant_id;
  
  -- Generate display name
  SELECT 
    m.name || ' ' || 
    COALESCE(i18n.model_name, '') ||
    CASE WHEN hv.color IS NOT NULL THEN ' (' || hv.color || ')' ELSE '' END ||
    CASE WHEN l.name IS NOT NULL THEN ' ' || l.name ELSE '' END ||
    CASE WHEN l.focal_length_mm IS NOT NULL THEN ' ' || l.focal_length_mm || 'mm' ELSE '' END ||
    CASE WHEN s.name IS NOT NULL THEN ' ' || s.name ELSE '' END
  INTO NEW.display_name
  FROM housing_variants hv
  JOIN camera_models cm ON hv.camera_model_id = cm.id
  JOIN manufacturers m ON cm.manufacturer_id = m.id
  LEFT JOIN camera_model_i18n i18n ON cm.id = i18n.camera_model_id
  LEFT JOIN lenses l ON NEW.lens_id = l.id
  LEFT JOIN shutters s ON NEW.shutter_id = s.id
  WHERE hv.id = NEW.housing_variant_id;
  
  -- Generate search text
  NEW.search_text := NEW.display_name || ' ' || COALESCE(NEW.goergens_full_id, '');
  
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- Trigger on INSERT
CREATE TRIGGER trg_combo_denorm_insert
BEFORE INSERT ON lens_shutter_combos
FOR EACH ROW
EXECUTE FUNCTION update_combo_denormalized();

-- Trigger on UPDATE (only when relevant fields change)
CREATE TRIGGER trg_combo_denorm_update
BEFORE UPDATE ON lens_shutter_combos
FOR EACH ROW
WHEN (
  OLD.housing_variant_id IS DISTINCT FROM NEW.housing_variant_id OR
  OLD.lens_id IS DISTINCT FROM NEW.lens_id OR
  OLD.shutter_id IS DISTINCT FROM NEW.shutter_id
)
EXECUTE FUNCTION update_combo_denormalized();

COMMENT ON FUNCTION update_combo_denormalized IS 'Maintains denormalized fields in lens_shutter_combos for query performance';

-- ==========================================
-- FUNCTION: Version Increment & Timestamp
-- ==========================================
CREATE OR REPLACE FUNCTION update_version_and_timestamp()
RETURNS TRIGGER AS $$
BEGIN
  NEW.version := OLD.version + 1;
  NEW.updated_at := NOW();
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- Apply to main tables
CREATE TRIGGER trg_mfg_version 
BEFORE UPDATE ON manufacturers
FOR EACH ROW 
EXECUTE FUNCTION update_version_and_timestamp();

CREATE TRIGGER trg_models_version 
BEFORE UPDATE ON camera_models
FOR EACH ROW 
EXECUTE FUNCTION update_version_and_timestamp();

CREATE TRIGGER trg_variants_version 
BEFORE UPDATE ON housing_variants
FOR EACH ROW 
EXECUTE FUNCTION update_version_and_timestamp();

CREATE TRIGGER trg_combos_version 
BEFORE UPDATE ON lens_shutter_combos
FOR EACH ROW 
EXECUTE FUNCTION update_version_and_timestamp();

COMMENT ON FUNCTION update_version_and_timestamp IS 'Increments version number and updates timestamp on every change';

-- ==========================================
-- FUNCTION: Maintain Camera Models History
-- ==========================================
CREATE OR REPLACE FUNCTION camera_models_to_history()
RETURNS TRIGGER AS $$
BEGIN
  IF TG_OP = 'UPDATE' THEN
    INSERT INTO camera_models_history (
      id, manufacturer_id, goergens_model_number, body_type, 
      viewfinder_type, format_code, year_first, year_last,
      version, changed_at, changed_by, change_type
    )
    VALUES (
      OLD.id, OLD.manufacturer_id, OLD.goergens_model_number, OLD.body_type,
      OLD.viewfinder_type, OLD.format_code, OLD.year_first, OLD.year_last,
      OLD.version, NOW(), NEW.updated_by, 'UPDATE'
    );
  ELSIF TG_OP = 'DELETE' THEN
    INSERT INTO camera_models_history (
      id, manufacturer_id, goergens_model_number, body_type,
      viewfinder_type, format_code, year_first, year_last,
      version, changed_at, changed_by, change_type
    )
    VALUES (
      OLD.id, OLD.manufacturer_id, OLD.goergens_model_number, OLD.body_type,
      OLD.viewfinder_type, OLD.format_code, OLD.year_first, OLD.year_last,
      OLD.version, NOW(), NULL, 'DELETE'
    );
  END IF;
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trg_models_history
AFTER UPDATE OR DELETE ON camera_models
FOR EACH ROW
EXECUTE FUNCTION camera_models_to_history();

COMMENT ON FUNCTION camera_models_to_history IS 'Maintains historical versions of camera models';

-- ==========================================
-- FUNCTION: Maintain Combos History
-- ==========================================
CREATE OR REPLACE FUNCTION lens_shutter_combos_to_history()
RETURNS TRIGGER AS $$
BEGIN
  IF TG_OP = 'UPDATE' THEN
    INSERT INTO lens_shutter_combos_history (
      id, housing_variant_id, goergens_combo_number, lens_id, shutter_id,
      weight_g, width_mm, height_mm, depth_mm, specs,
      version, changed_at, changed_by, change_type
    )
    VALUES (
      OLD.id, OLD.housing_variant_id, OLD.goergens_combo_number, OLD.lens_id, OLD.shutter_id,
      OLD.weight_g, OLD.width_mm, OLD.height_mm, OLD.depth_mm, OLD.specs,
      OLD.version, NOW(), NEW.updated_by, 'UPDATE'
    );
  ELSIF TG_OP = 'DELETE' THEN
    INSERT INTO lens_shutter_combos_history (
      id, housing_variant_id, goergens_combo_number, lens_id, shutter_id,
      weight_g, width_mm, height_mm, depth_mm, specs,
      version, changed_at, changed_by, change_type
    )
    VALUES (
      OLD.id, OLD.housing_variant_id, OLD.goergens_combo_number, OLD.lens_id, OLD.shutter_id,
      OLD.weight_g, OLD.width_mm, OLD.height_mm, OLD.depth_mm, OLD.specs,
      OLD.version, NOW(), NULL, 'DELETE'
    );
  END IF;
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trg_combos_history
AFTER UPDATE OR DELETE ON lens_shutter_combos
FOR EACH ROW
EXECUTE FUNCTION lens_shutter_combos_to_history();

COMMENT ON FUNCTION lens_shutter_combos_to_history IS 'Maintains historical versions of camera combinations';

-- ==========================================
-- FUNCTION: Validate Goergens ID Structure
-- ==========================================
CREATE OR REPLACE FUNCTION validate_goergens_structure()
RETURNS TABLE(combo_id INT, goergens_id VARCHAR, issue TEXT) AS $$
BEGIN
  -- Check model numbers are consistent
  RETURN QUERY
  SELECT 
    lsc.id,
    lsc.goergens_full_id,
    'Inconsistent model number in same camera_model'::TEXT AS issue
  FROM lens_shutter_combos lsc
  JOIN housing_variants hv ON lsc.housing_variant_id = hv.id
  JOIN camera_models cm ON hv.camera_model_id = cm.id
  WHERE split_part(lsc.goergens_full_id, ' ', 3) != cm.goergens_model_number;
  
  -- Check variant letters are consistent
  RETURN QUERY
  SELECT 
    lsc.id,
    lsc.goergens_full_id,
    'Inconsistent variant letter'::TEXT AS issue
  FROM lens_shutter_combos lsc
  JOIN housing_variants hv ON lsc.housing_variant_id = hv.id
  WHERE substring(split_part(lsc.goergens_full_id, ' ', 4), 1, 1) != hv.goergens_variant_letter;
END;
$$ LANGUAGE plpgsql;

COMMENT ON FUNCTION validate_goergens_structure IS 'Validates that Goergens IDs match the hierarchy structure';