"""Tool proxy between agent and MCP: whitelist, budget, prefix filter, trajectory log."""
import json
import re
import time

MODEL_TOOLS = {
    "sap_search_object", "sap_pull_source", "sap_object_structure", "sap_object_members",
    "sap_usage_references", "sap_element_info", "sap_inactive_objects", "sap_short_dumps",
    "sap_sql_query", "sap_create_object", "sap_push_source", "sap_push_element",
    "sap_push_message", "sap_activate", "sap_syntax_check", "sap_check_object",
    "sap_run_unit_test", "sap_atc_run", "sap_pretty_print", "sap_run_class",
}
WRITE_TOOLS = {"sap_create_object", "sap_push_source", "sap_push_element",
               "sap_push_message", "sap_activate"}
RUN_PREFIX = re.compile(r"^Z\d[0-9A-Z]{5,6}_", re.I)


class BudgetExceeded(Exception):
    pass


class ToolProxy:
    def __init__(self, mcp, prefix, budget, log_path):
        self.mcp = mcp
        self.prefix = prefix.upper()
        self.max_calls = budget.get("max_tool_calls", 60)
        self.max_activations = budget.get("max_activations", 15)
        self.calls = 0
        self.activations = 0
        self.fail_streak = 0
        self.max_fail_streak = 0
        self.log = open(log_path, "a")

    def schemas(self):
        return [t for t in self.mcp.list_tools() if t["name"] in MODEL_TOOLS]

    def _foreign(self, name):
        n = (name or "").upper()
        return bool(RUN_PREFIX.match(n)) and not n.startswith(self.prefix)

    def _filter(self, tool, text):
        if tool not in ("sap_search_object", "sap_usage_references"):
            return text
        try:
            data = json.loads(text)
        except ValueError:
            return text
        if isinstance(data, list):
            data = [d for d in data if not self._foreign(d.get("name") if isinstance(d, dict) else "")]
            return json.dumps(data)
        return text

    def call(self, tool, args):
        entry = {"t": time.time(), "tool": tool, "args": args}
        if tool not in MODEL_TOOLS:
            result = (True, f"Tool {tool} is not available.")
        elif self.calls >= self.max_calls:
            raise BudgetExceeded(f"max_tool_calls={self.max_calls}")
        else:
            self.calls += 1
            name = str(args.get("objectName", "")).upper()
            if tool in WRITE_TOOLS and self._foreign(name):
                result = (True, f"{name} is not available.")
            else:
                if tool in WRITE_TOOLS and (tool == "sap_activate" or args.get("activate", True)):
                    self.activations += 1
                err, text = self.mcp.call(tool, args)
                result = (err, self._filter(tool, text))
                if tool in WRITE_TOOLS:
                    failed = err or '"success":false' in text.replace(" ", "")
                    self.fail_streak = self.fail_streak + 1 if failed else 0
                    self.max_fail_streak = max(self.max_fail_streak, self.fail_streak)
        entry["is_error"], entry["result"] = result[0], result[1][:20000]
        self.log.write(json.dumps(entry) + "\n")
        self.log.flush()
        return result

    def note(self, kind, content):
        self.log.write(json.dumps({"t": time.time(), "kind": kind, "content": content}) + "\n")
        self.log.flush()