Kling AI Cost Controls

import time
from dataclasses import dataclass, field

@dataclass
class BudgetGuard:
    """Enforce daily credit budget with alerting."""
    daily_limit: int = 1000
    alert_threshold: float = 0.8  # alert at 80%
    _used: int = 0
    _reset_time: float = field(default_factory=time.time)
    _alerts_sent: set = field(default_factory=set)

    def _check_reset(self):
        if time.time() - self._reset_time > 86400:
            self._used = 0
            self._reset_time = time.time()
            self._alerts_sent.clear()

    def estimate_credits(self, duration: int = 5, mode: str = "standard",
                         audio: bool = False) -> int:
        base = {(5, "standard"): 10, (5, "professional"): 35,
                (10, "standard"): 20, (10, "professional"): 70}
        credits = base.get((duration, mode), 10)
        if audio:
            credits *= 5
        return credits

    def check(self, credits_needed: int) -> bool:
        self._check_reset()

        # Check alert threshold
        usage_pct = (self._used + credits_needed) / self.daily_limit
        if usage_pct >= self.alert_threshold and "80pct" not in self._alerts_sent:
            self._alerts_sent.add("80pct")
            self._on_alert(f"Budget at {usage_pct:.0%} ({self._used + credits_needed}/{self.daily_limit})")

        if self._used + credits_needed > self.daily_limit:
            raise RuntimeError(
                f"Daily budget exceeded: {self._used} + {credits_needed} > {self.daily_limit} credits"
            )
        return True

    def record(self, credits: int):
        self._used += credits

    def _on_alert(self, message: str):
        """Override for custom alerting (Slack, email, PagerDuty)."""
        print(f"ALERT: {message}")

    @property
    def remaining(self) -> int:
        self._check_reset()
        return max(0, self.daily_limit - self._used)

    @property
    def usage_report(self) -> dict:
        self._check_reset()
        return {
            "used": self._used,
            "limit": self.daily_limit,
            "remaining": self.remaining,
            "usage_pct": f"{(self._used / self.daily_limit) * 100:.1f}%",
        }

def pre_batch_check(prompts: list, budget: BudgetGuard,
                    duration: int = 5, mode: str = "standard"):
    """Estimate and validate batch cost before submission."""
    per_video = budget.estimate_credits(duration, mode)
    total = len(prompts) * per_video

    print(f"Batch estimate: {len(prompts)} videos x {per_video} credits = {total} credits")
    print(f"Budget remaining: {budget.remaining}")

    if total > budget.remaining:
        raise RuntimeError(
            f"Batch needs {total} credits but only {budget.remaining} remaining. "
            f"Reduce to {budget.remaining // per_video} videos or lower mode."
        )
    return total

class CostAwareKlingClient:
    """Kling client that enforces budget on every request."""

    def __init__(self, base_client, budget: BudgetGuard):
        self.client = base_client
        self.budget = budget

    def text_to_video(self, prompt: str, **kwargs):
        credits = self.budget.estimate_credits(
            kwargs.get("duration", 5),
            kwargs.get("mode", "standard"),
            kwargs.get("audio", False),
        )
        self.budget.check(credits)

        result = self.client.text_to_video(prompt, **kwargs)
        self.budget.record(credits)
        return result

import json
from datetime import datetime

class UsageTracker:
    """Log every generation for cost analysis."""

    def __init__(self, log_file: str = "kling_usage.jsonl"):
        self.log_file = log_file

    def log(self, task_id: str, credits: int, model: str,
            duration: int, mode: str, prompt: str):
        entry = {
            "timestamp": datetime.utcnow().isoformat(),
            "task_id": task_id,
            "credits": credits,
            "model": model,
            "duration": duration,
            "mode": mode,
            "prompt_preview": prompt[:100],
        }
        with open(self.log_file, "a") as f:
            f.write(json.dumps(entry) + "\n")