feat(deepseek): Implement Phase 1 infrastructure and provider interface

ai_client.py

@@ -65,6 +65,11 @@ _GEMINI_CACHE_TTL = 3600
 _anthropic_client = None
 _anthropic_history: list[dict] = []
 _anthropic_history_lock = threading.Lock()
+
+_deepseek_client = None
+_deepseek_history: list[dict] = []
+_deepseek_history_lock = threading.Lock()
+
 _send_lock = threading.Lock()
 
 _gemini_cli_adapter = None
@@ -159,10 +164,10 @@ def _load_credentials() -> dict:
             f"Create a credentials.toml with:\n"
             f"  [gemini]\n  api_key = \"your-key\"\n"
             f"  [anthropic]\n  api_key = \"your-key\"\n"
+            f"  [deepseek]\n  api_key = \"your-key\"\n"
             f"Or set SLOP_CREDENTIALS env var to a custom path."
         )
 
-
 # ------------------------------------------------------------------ provider errors
 
 class ProviderError(Exception):
@@ -241,6 +246,21 @@ def _classify_gemini_error(exc: Exception) -> ProviderError:
     return ProviderError("unknown", "gemini", exc)
 
 
+def _classify_deepseek_error(exc: Exception) -> ProviderError:
+    body = str(exc).lower()
+    if "429" in body or "rate" in body:
+        return ProviderError("rate_limit", "deepseek", exc)
+    if "401" in body or "403" in body or "auth" in body or "api key" in body:
+        return ProviderError("auth", "deepseek", exc)
+    if "402" in body or "balance" in body or "billing" in body:
+        return ProviderError("balance", "deepseek", exc)
+    if "quota" in body or "limit exceeded" in body:
+        return ProviderError("quota", "deepseek", exc)
+    if "connection" in body or "timeout" in body or "network" in body:
+        return ProviderError("network", "deepseek", exc)
+    return ProviderError("unknown", "deepseek", exc)
+
+
 # ------------------------------------------------------------------ provider setup
 
 def set_provider(provider: str, model: str):
@@ -280,6 +300,11 @@ def reset_session():
     _anthropic_client = None
     with _anthropic_history_lock:
         _anthropic_history = []
+
+    _deepseek_client = None
+    with _deepseek_history_lock:
+        _deepseek_history = []
+
     _CACHED_ANTHROPIC_TOOLS = None
     file_cache.reset_client()
 
@@ -308,6 +333,8 @@ def list_models(provider: str) -> list[str]:
         return _list_gemini_models(creds["gemini"]["api_key"])
     elif provider == "anthropic":
         return _list_anthropic_models()
+    elif provider == "deepseek":
+        return _list_deepseek_models(creds["deepseek"]["api_key"])
     return []
 
 
@@ -340,6 +367,14 @@ def _list_anthropic_models() -> list[str]:
         raise _classify_anthropic_error(exc) from exc
 
 
+def _list_deepseek_models(api_key: str) -> list[str]:
+    """
+    List available DeepSeek models.
+    """
+    # For now, return the models specified in the requirements
+    return ["deepseek-chat", "deepseek-reasoner", "deepseek-v3", "deepseek-r1"]
+
+
 # ------------------------------------------------------------------ tool definition
 
 TOOL_NAME = "run_powershell"
@@ -1385,6 +1420,41 @@ def _send_anthropic(md_content: str, user_message: str, base_dir: str, file_item
         raise _classify_anthropic_error(exc) from exc
 
 
+# ------------------------------------------------------------------ deepseek
+
+def _ensure_deepseek_client():
+    global _deepseek_client
+    if _deepseek_client is None:
+        creds = _load_credentials()
+        # Placeholder for Dedicated DeepSeek SDK instantiation
+        # import deepseek
+        # _deepseek_client = deepseek.DeepSeek(api_key=creds["deepseek"]["api_key"])
+        pass
+
+
+def _send_deepseek(md_content: str, user_message: str, base_dir: str,
+                   file_items: list[dict] | None = None,
+                   discussion_history: str = "") -> str:
+    """
+    Placeholder implementation for DeepSeek provider.
+    Aligns with Gemini/Anthropic patterns for history and tool calling.
+    """
+    try:
+        _ensure_deepseek_client()
+        mcp_client.configure(file_items or [], [base_dir])
+
+        # TODO: Implement full DeepSeek logic in Phase 2
+        # 1. Build system prompt with context
+        # 2. Manage _deepseek_history
+        # 3. Handle reasoning traces for R1
+        # 4. Handle tool calling loop
+
+        raise ValueError("DeepSeek provider is currently in the infrastructure phase and not yet fully implemented.")
+
+    except Exception as e:
+        raise _classify_deepseek_error(e) from e
+
+
 # ------------------------------------------------------------------ unified send
 
 def send(
@@ -1413,6 +1483,8 @@ def send(
             return _send_gemini_cli(md_content, user_message, base_dir, file_items, discussion_history)
         elif _provider == "anthropic":
             return _send_anthropic(md_content, user_message, base_dir, file_items, discussion_history)
+        elif _provider == "deepseek":
+            return _send_deepseek(md_content, user_message, base_dir, file_items, discussion_history)
         raise ValueError(f"unknown provider: {_provider}")
 
 def get_history_bleed_stats(md_content: str | None = None) -> dict:
@@ -1516,7 +1588,7 @@ def get_history_bleed_stats(md_content: str | None = None) -> dict:
             # Stats from CLI use 'input_tokens' or 'input'
             u = _gemini_cli_adapter.last_usage
             current_tokens = u.get("input_tokens") or u.get("input", 0)
-        
+
         percentage = (current_tokens / limit_tokens) * 100 if limit_tokens > 0 else 0
         return {
             "provider": "gemini_cli",
@@ -1524,7 +1596,15 @@ def get_history_bleed_stats(md_content: str | None = None) -> dict:
             "current": current_tokens,
             "percentage": percentage,
         }
-    
+    elif _provider == "deepseek":
+        # Placeholder for DeepSeek token estimation
+        return {
+            "provider": "deepseek",
+            "limit": 64000, # Common limit for deepseek
+            "current": 0,
+            "percentage": 0,
+        }
+
     # Default empty state
     return {
         "provider": _provider,