"""Pydantic coercion helpers for tool input schemas.

LLMs stringify everything — they send `"95727067"` when your schema
expects `int`, or `'[{"id":1}]'` when you expect `list[dict]`. Pydantic
strict mode returns 422 and the agent fails.

Use these as `mode="before"` validators on every tool input schema.

Example:

    from pydantic import BaseModel, field_validator
    from wxo.tools.python._coercion_helpers import _coerce_int, _coerce_list

    class ResetPasswordInput(BaseModel):
        user_id: int
        groups: list[str]
        _coerce_user_id = field_validator("user_id", mode="before")(_coerce_int)
        _coerce_groups = field_validator("groups", mode="before")(_coerce_list)

See `docs/known-issues.md#i-003` for the full story.
"""
from __future__ import annotations

import json
from typing import Any


def _coerce_int(v: Any) -> Any:
    """Accepts int or stringified int."""
    if isinstance(v, str):
        s = v.strip()
        if s.lstrip("-").isdigit():
            return int(s)
    return v


def _coerce_float(v: Any) -> Any:
    if isinstance(v, str):
        try:
            return float(v.strip())
        except ValueError:
            pass
    return v


def _coerce_bool(v: Any) -> Any:
    """Accepts bool, 'true'/'false', '1'/'0', 'yes'/'no'."""
    if isinstance(v, bool):
        return v
    if isinstance(v, str):
        s = v.strip().lower()
        if s in ("true", "1", "yes", "y"):
            return True
        if s in ("false", "0", "no", "n"):
            return False
    return v


def _coerce_list(v: Any) -> Any:
    """Accepts list, stringified JSON list, or single value (wrapped)."""
    if isinstance(v, list):
        return v
    if isinstance(v, str):
        s = v.strip()
        if s.startswith("[") and s.endswith("]"):
            try:
                parsed = json.loads(s)
                if isinstance(parsed, list):
                    return parsed
            except json.JSONDecodeError:
                pass
        # Fallback: wrap single value
        return [v]
    return v


def _coerce_dict(v: Any) -> Any:
    """Accepts dict or stringified JSON dict."""
    if isinstance(v, dict):
        return v
    if isinstance(v, str):
        s = v.strip()
        if s.startswith("{") and s.endswith("}"):
            try:
                parsed = json.loads(s)
                if isinstance(parsed, dict):
                    return parsed
            except json.JSONDecodeError:
                pass
    return v