feat: implement automatic margin pricing and margin reverse engineering in sync

backend/app/services/website_sync.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import json
 import logging
-from decimal import Decimal
+from decimal import Decimal, ROUND_HALF_UP
 from datetime import datetime, timezone
 from typing import Any
 
@@ -14,7 +14,7 @@ from app.models.upstream import Upstream
 from app.models.upstream_key import UpstreamGeneratedKey
 from app.models.website import Website, WebsiteGroupBinding, WebsiteSyncLog
 from app.services.auth_config import normalize_auth_config
-from app.services.website_client import Sub2ApiWebsiteClient, WebsiteError, _extract_id, calculate_target_rate
+from app.services.website_client import Sub2ApiWebsiteClient, WebsiteError, _extract_id, calculate_target_rate, parse_positive_decimal
 from app.services.upstream_client import UpstreamClient
 from app.services import webhook_service
 from app.utils.number import fixed_decimal_string
@@ -168,6 +168,21 @@ def sync_binding(db: Session, binding: WebsiteGroupBinding, write: bool = True)
         })
     try:
         target_rate = calculate_target_rate([item.get("rate") for item in source_rates], binding.percent, binding.algorithm)
+        if binding.algorithm == "priority_weighted_plus_percent":
+            rates = [rate for rate in (parse_positive_decimal(item.get("rate")) for item in source_rates) if rate is not None]
+            if rates:
+                rates_sorted = sorted(rates)
+                N = len(rates_sorted)
+                if N == 1:
+                    base = rates_sorted[0]
+                else:
+                    w1 = Decimal("0.85")
+                    w_others = Decimal("0.15") / Decimal(N - 1)
+                    base = rates_sorted[0] * w1 + sum(rates_sorted[1:], Decimal("0")) * w_others
+
+                if base > 0:
+                    effective_percent = (target_rate / base - Decimal("1")) * Decimal("100")
+                    binding.percent = fixed_decimal_string(effective_percent.quantize(Decimal("0.01"), rounding=ROUND_HALF_UP), 2)
     except Exception as exc:
         return _log(db, binding, website, source_rates, "failed", str(exc))