#!/usr/bin/env python3
"""Quota Reset ETR — calculate Estimated Time to Reset from provider error messages.

Parses quota-exhaustion errors from common providers (Z.AI/GLM, DeepSeek,
OpenRouter, Anthropic, OpenAI) and computes the reset time in UTC and local
time. Outputs a cron-ready timestamp for scheduling retry.

Usage:
    python3 quota_reset_etr.py "error message or timestamp string"
    python3 quota_reset_etr.py "2026-06-18 15:43:27" --tz Asia/Shanghai

Output:
    {
      "status": "quota_exhausted",
      "reset_utc": "2026-06-18T07:43:27Z",
      "reset_local": "2026-06-18T09:43:27+02:00",
      "cron_iso": "2026-06-18T09:44:00+02:00",
      "provider": "z.ai",
      "confidence": "high",
      "retry_after_seconds": 12345,
      "human": "Resets Jun 18 at 09:43 CEST (09:44 safe retry)"
    }
"""

from __future__ import annotations

import argparse
import json
import re
import sys
from datetime import datetime, timedelta, timezone
from typing import Optional

# ── Provider timezone map ──────────────────────────────
# Sources of truth per provider, verified against real error messages.

PROVIDER_TZ = {
    "z.ai": "Asia/Shanghai",          # Zhipu AI — Beijing UTC+8
    "glm": "Asia/Shanghai",           # GLM API — same as z.ai
    "deepseek": "Asia/Shanghai",      # DeepSeek — Hangzhou UTC+8
    "openrouter": "UTC",              # OpenRouter — UTC
    "anthropic": "America/Los_Angeles",  # Anthropic — PST/PDT
    "openai": "America/Los_Angeles",  # OpenAI — PST/PDT
}

# ── Error message patterns ─────────────────────────────

# Chinese-style: "您的限额将在 2026-06-18 15:43:27 重置"
CN_RESET_PATTERN = re.compile(
    r"(\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}:\d{2})\s*重置"
)

# English-style: "quota will reset on 2026-06-18T15:43:27Z"
EN_RESET_PATTERN = re.compile(
    r"reset\s+(?:on\s+)?(\d{4}-\d{2}-\d{2}[T\s]\d{2}:\d{2}:\d{2})",
    re.IGNORECASE,
)

# ISO 8601 with timezone: "2026-06-18T15:43:27+08:00"
ISO_TZ_PATTERN = re.compile(
    r"(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}[+-]\d{2}:\d{2})"
)

# Retry-After header style: seconds
RETRY_AFTER_PATTERN = re.compile(
    r"retry[_-]after[:\s]+(\d+)", re.IGNORECASE
)

# Plain timestamp: "2026-06-18 15:43:27"
PLAIN_TS_PATTERN = re.compile(
    r"(\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}:\d{2})"
)

# ── Parse functions ────────────────────────────────────

def parse_reset_time(
    error_text: str,
    provider_tz: Optional[str] = None,
) -> tuple[datetime, str, str]:
    """Parse a quota error message and return (reset_utc, provider, confidence).

    Returns (datetime, provider_name, confidence_level).
    Confidence: "high" (explicit timestamp), "medium" (provider default),
    "low" (generic fallback).
    """
    # Try ISO with timezone first (gold standard)
    m = ISO_TZ_PATTERN.search(error_text)
    if m:
        dt = datetime.fromisoformat(m.group(1))
        return dt.astimezone(timezone.utc), "iso8601", "high"

    # Try Chinese reset pattern
    m = CN_RESET_PATTERN.search(error_text)
    if m:
        dt = datetime.strptime(m.group(1), "%Y-%m-%d %H:%M:%S")
        tz_name = provider_tz or "Asia/Shanghai"
        return _to_utc(dt, tz_name), "z.ai", "high"

    # Try English reset pattern
    m = EN_RESET_PATTERN.search(error_text)
    if m:
        ts = m.group(1).replace(" ", "T")
        # Check if timezone suffix present
        if "+" in ts or ts.endswith("Z"):
            dt = datetime.fromisoformat(ts.replace("Z", "+00:00"))
        else:
            dt = datetime.strptime(ts[:19], "%Y-%m-%dT%H:%M:%S")
            tz_name = provider_tz or "UTC"
            dt = _to_utc(dt, tz_name)
        return dt.astimezone(timezone.utc), "generic", "high"

    # Try plain timestamp
    m = PLAIN_TS_PATTERN.search(error_text)
    if m:
        dt = datetime.strptime(m.group(1), "%Y-%m-%d %H:%M:%S")
        tz_name = provider_tz or "UTC"
        return _to_utc(dt, tz_name), "generic", "medium"

    # Try Retry-After (seconds from now)
    m = RETRY_AFTER_PATTERN.search(error_text)
    if m:
        seconds = int(m.group(1))
        reset = datetime.now(timezone.utc) + timedelta(seconds=seconds)
        return reset, "generic", "medium"

    # Generic 429 fallback: guess 1 hour
    if "429" in error_text or "quota" in error_text.lower():
        reset = datetime.now(timezone.utc) + timedelta(hours=1)
        return reset, "generic", "low"

    raise ValueError(f"Cannot parse reset time from: {error_text[:200]}")


def _to_utc(dt: datetime, tz_name: str) -> datetime:
    """Convert a naive datetime from a named timezone to UTC."""
    import zoneinfo
    tz = zoneinfo.ZoneInfo(tz_name)
    return dt.replace(tzinfo=tz).astimezone(timezone.utc)


def detect_provider(error_text: str) -> Optional[str]:
    """Guess the provider from error text patterns."""
    text = error_text.lower()
    # Chinese providers
    if "z.ai" in text or "智谱" in text or "zhipu" in text:
        return "z.ai"
    if "glm" in text or "使用上限" in error_text or "重置" in error_text:
        return "glm"  # GLM API — Chinese quota messages
    if "deepseek" in text:
        return "deepseek"
    # Western providers
    if "openrouter" in text:
        return "openrouter"
    if "anthropic" in text:
        return "anthropic"
    if "openai" in text:
        return "openai"
    return None


# ── Main ───────────────────────────────────────────────

def main():
    parser = argparse.ArgumentParser(
        description="Calculate quota reset ETR from provider error messages"
    )
    parser.add_argument(
        "input",
        nargs="?",
        help="Error message or timestamp string (reads stdin if omitted)",
    )
    parser.add_argument(
        "--tz",
        help="Timezone override (e.g., Asia/Shanghai, UTC, America/Los_Angeles)",
    )
    parser.add_argument(
        "--cron-offset",
        type=int,
        default=60,
        help="Seconds to add for safe cron retry window (default: 60)",
    )
    args = parser.parse_args()

    # Read input
    if args.input:
        text = args.input
    elif not sys.stdin.isatty():
        text = sys.stdin.read().strip()
    else:
        parser.print_help()
        sys.exit(1)

    if not text:
        print(json.dumps({"status": "error", "message": "empty input"}))
        sys.exit(1)

    # Detect provider
    provider = detect_provider(text)
    provider_tz = args.tz or PROVIDER_TZ.get(provider or "", "UTC")

    try:
        reset_utc, detected_provider, confidence = parse_reset_time(
            text, provider_tz
        )
    except ValueError as e:
        print(json.dumps({"status": "error", "message": str(e)}))
        sys.exit(1)

    provider = provider or detected_provider
    now_utc = datetime.now(timezone.utc)
    retry_after = max(0, int((reset_utc - now_utc).total_seconds()))

    # Safe cron time: reset + buffer
    cron_dt = reset_utc + timedelta(seconds=args.cron_offset)

    # Local time for display
    local_tz = datetime.now().astimezone().tzinfo
    reset_local = reset_utc.astimezone(local_tz)

    result = {
        "status": "quota_exhausted",
        "provider": provider,
        "confidence": confidence,
        "reset_utc": reset_utc.strftime("%Y-%m-%dT%H:%M:%SZ"),
        "reset_local": reset_local.strftime("%Y-%m-%dT%H:%M:%S%z"),
        "cron_iso": cron_dt.strftime("%Y-%m-%dT%H:%M:%S%z"),
        "retry_after_seconds": retry_after,
        "human": (
            f"Resets {reset_local.strftime('%b %d at %H:%M')} "
            f"{reset_local.tzname()} "
            f"({cron_dt.strftime('%H:%M')} safe retry)"
        ),
    }

    print(json.dumps(result, indent=2))

    if confidence == "low":
        print("\n# WARNING: low confidence — verify manually", file=sys.stderr)
        sys.exit(2)


if __name__ == "__main__":
    main()