"""Phase 11.3.2 partial migration for startup_profiler.py.

CONTEXT-MANAGER EXCEPTION: StartupProfiler.phase() IS a context manager
(decorated with @contextmanager; used in 13 'with profiler.phase(...)'
call sites in src/gui_2.py). It CANNOT return Result[None] from the
except body because @contextmanager requires the function to yield
(not return), and the except body is inside a finally block.

The plan claimed "phase() is NOT a context manager" - this is factually
wrong. We do the best partial migration: extract a Result-returning
helper for the stderr.write, and document the constraint.

The audit classifies the existing site as INTERNAL_COMPLIANT via
Heuristic #19 (catch+log). The plan's rejection was based on the
incorrect assumption that phase() is a regular method.
"""
from __future__ import annotations
from pathlib import Path

p = Path("src/startup_profiler.py")
content = p.read_text(encoding="utf-8")

# 1. Add Result import
old_imports = "import time\nimport sys\nfrom contextlib import contextmanager\nfrom dataclasses import dataclass, field\nfrom typing import Any, Iterator"
new_imports = (
    "import time\n"
    "import sys\n"
    "from contextlib import contextmanager\n"
    "from dataclasses import dataclass, field\n"
    "from typing import Any, Iterator\n"
    "\n"
    "from src.result_types import ErrorInfo, ErrorKind, Result"
)
assert old_imports in content, "imports marker not found"
content = content.replace(old_imports, new_imports)

# 2. Add _log_phase_output helper BEFORE @dataclass StartupProfiler
helper = '''

def _log_phase_output(line: str, phase_name: str) -> Result[None]:
 """Best-effort stderr write for phase timing output. Returns Result[None].

 Used by phase() (which is a @contextmanager; cannot return Result from
 its except body because @contextmanager requires yield, not return, and
 the except is in a finally block).
 """
 try:
  sys.stderr.write(line)
  sys.stderr.flush()
  return Result(data=None)
 except OSError as e:
  return Result(data=None, errors=[ErrorInfo(
   kind=ErrorKind.INTERNAL,
   message=f"phase output failed for {phase_name}: {e}",
   source="startup_profiler._log_phase_output",
   original=e,
  )])
'''

old_class_marker = "\n\n@dataclass\nclass StartupProfiler:"
new_class_marker = helper + "\n\n@dataclass\nclass StartupProfiler:"
assert old_class_marker in content, "class marker not found"
content = content.replace(old_class_marker, new_class_marker)

# 3. Replace the except body in phase() to use _log_phase_output
old_except = (
    "   try:\n"
    "    sys.stderr.write(f\"[startup] {name}: {(p.end_ts - p.start_ts) * 1000.0:.1f}ms\\n\")\n"
    "    sys.stderr.flush()\n"
    "   except OSError as e:\n"
    "    sys.stderr.write(f\"[startup] phase output failed for {name}: {e}\\n\")"
)
new_except = (
    "   log_line = f\"[startup] {name}: {(p.end_ts - p.start_ts) * 1000.0:.1f}ms\\n\"\n"
    "   log_result = _log_phase_output(log_line, name)\n"
    "   if not log_result.ok:\n"
    "    _log_phase_output(f\"[startup] phase output failed for {name}: {log_result.errors[0].message}\\n\", name)"
)
assert old_except in content, "except marker not found"
content = content.replace(old_except, new_except)

p.write_text(content, encoding="utf-8", newline="")
print("ok")