import json
import unittest
from pathlib import Path


REPO_ROOT = Path(__file__).resolve().parents[1]
CRM_PACK = REPO_ROOT / "salesforce-crm-standard"


def load_json(path: Path):
    with path.open(encoding="utf-8") as handle:
        return json.load(handle)


def object_spec(api_name: str):
    for spec in load_json(CRM_PACK / "objects" / "standard_objects_spec.json"):
        if spec.get("apiName") == api_name:
            return spec
    raise AssertionError(f"{api_name} object spec missing")


def field_spec(spec: dict, api_name: str):
    for field in spec.get("fields", []):
        if field.get("apiName") == api_name:
            return field
    raise AssertionError(f"{spec.get('apiName')}.{api_name} field spec missing")


def related_list_rule(key: str):
    payload = load_json(CRM_PACK / "related_lists" / "standard_related_list_rules.json")
    for rule in payload.get("rules", []):
        if rule.get("key") == key:
            return rule
    raise AssertionError(f"{key} related-list rule missing")


class DisplayNameFieldContractsTest(unittest.TestCase):
    def assert_product_display_name(self, object_api_name: str):
        spec = object_spec(object_api_name)
        self.assertEqual(spec.get("displayNameField"), "Product2Id")

        product = field_spec(spec, "Product2Id")
        self.assertEqual(product.get("type"), "reference")
        self.assertEqual(product.get("referenceTo"), ["Product2"])
        self.assertEqual(product.get("relationshipName"), "Product2")

    def test_line_item_objects_use_product_as_display_name(self):
        # These objects are central to Add Products / Create Quote flows. Product
        # identity is the user-facing label; PricebookEntry is implementation
        # detail unless a workflow explicitly needs pricebook-row inspection.
        for object_api_name in ("OpportunityLineItem", "QuoteLineItem", "OrderItem"):
            with self.subTest(object=object_api_name):
                self.assert_product_display_name(object_api_name)

    def test_product_related_lists_start_with_product_column(self):
        expected = {
            "opportunity-line-items": "Product2Id",
            "quote-line-items": "Product2Id",
            "order-line-items": "Product2Id",
        }

        for key, first_field in expected.items():
            with self.subTest(related_list=key):
                rule = related_list_rule(key)
                self.assertGreater(len(rule.get("fields", [])), 0)
                self.assertEqual(rule["fields"][0], first_field)


if __name__ == "__main__":
    unittest.main()