Image Tryon

"""Cost tracking helper for skill subprocesses.

Skills that call sc-proxy via plain `requests` need to:
  1. Tag every paid call with a SC-CALLER-ID that ties it back to the user
     turn that triggered the skill (so the agent's per-turn cost summary
     shows the cost in the right cost card).
  2. After each call, parse the sc-proxy response headers
     (`X-Credits-Used`, `X-Credits-Api-Type`) and write a row to the cost
     ledger that the agent reads back when it builds the SSE
     `cost_summary` event.

This file is intentionally zero-dependency (stdlib only) so it can be
dropped into any skill folder without coupling to starchild-clawd internals.

Env vars consumed (set by the agent before dispatching the bash subprocess):
  - STARCHILD_TOOL_CALLER_ID  — opaque tag for the current tool call
  - STARCHILD_USER_TURN_ID    — uuid of the current user turn
  - STARCHILD_COST_LEDGER_DIR — optional override for ledger directory

When env vars are absent (e.g. running the script outside an agent), the
helpers degrade gracefully: caller-id falls back to a synthetic string so
the call still goes through, and ledger writes still happen for audit but
the user-turn reader will skip them.
"""
from __future__ import annotations

import fcntl
import json
import os
import time
from datetime import datetime, timezone
from pathlib import Path
from typing import Any, Dict, Optional
from urllib.parse import urlparse


_DEFAULT_LEDGER_DIR = "/data/.starchild/cost_ledger"

# Allowlisted request payload keys we forward into the ledger row's
# `details` field. MUST stay in sync with starchild-clawd's
# core/http_client._record_cost_to_ledger allowlist — anything not in
# that allowlist won't be picked up by the agent and won't render in
# the frontend cost card.
_PAYLOAD_ALLOWLIST = (
    # Identity
    "model", "provider",
    # Image geometry
    "aspect_ratio", "quality", "resolution", "image_size", "size",
    # Video / motion
    "duration", "duration_s", "fps", "motion_strength",
    # Quantity
    "n", "count",
    # Generation knobs
    "seed", "steps", "guidance_scale", "cfg_scale", "strength",
    "scheduler", "sampler",
    # Reference / mode hints
    "image_to_image", "image_to_video", "use_reference", "reference_count",
)


def caller_headers(extra: Optional[Dict[str, str]] = None,
                   tool_default: str = "skill") -> Dict[str, str]:
    """Return an HTTP-headers dict with SC-CALLER-ID filled in.

    Resolution order:
      1. `extra["SC-CALLER-ID"]` (case-insensitive) — caller wins.
      2. STARCHILD_TOOL_CALLER_ID env (set by the agent)
      3. Synthetic `f"{tool_default}:{int(time.time())}"` — tags the call so
         charges are attributable to *some* identifier even when the agent
         didn't inject one (standalone CLI runs, tests, cron).
    """
    merged: Dict[str, str] = dict(extra or {})
    has_caller = any(k.lower() == "sc-caller-id" for k in merged)
    if not has_caller:
        cid = os.environ.get("STARCHILD_TOOL_CALLER_ID") \
            or f"{tool_default}:{int(time.time())}"
        merged["SC-CALLER-ID"] = cid
    return merged


def record_response(response,
                    request_url: str,
                    request_payload: Optional[Dict[str, Any]] = None,
                    api_type_hint: Optional[str] = None) -> None:
    """Inspect a sc-proxy response and append a ledger row when paid.

    Best-effort. Silently no-ops when:
      - response carries no X-Credits-Used / X-Credits-Api-Type
      - cost is 0 or unparseable
      - file write fails
    Never raises — must not break a real request flow.
    """
    try:
        headers = getattr(response, "headers", None) or {}
        used = headers.get("X-Credits-Used") or headers.get("x-credits-used")
        api_type = (headers.get("X-Credits-Api-Type")
                    or headers.get("x-credits-api-type")
                    or api_type_hint)
        if not used or not api_type:
            return
        try: