#!/usr/bin/env python3
from __future__ import annotations

import argparse
import os
import sys
from pathlib import Path
from typing import Any

ROOT_DIR = Path(__file__).resolve().parents[1]
sys.path.insert(0, str(ROOT_DIR))

from services.storage.database_storage import DatabaseStorageBackend
from services.storage.factory import create_storage_backend


def _env_path(name: str, fallback: Path) -> Path:
    value = str(os.getenv(name) or "").strip()
    return Path(value) if value else fallback


def _data_dir() -> Path:
    persist_dir = Path(os.getenv("CHATGPT2API_PERSIST_DIR", "").strip() or "/app/persist")
    return _env_path("CHATGPT2API_DATA_DIR", persist_dir if persist_dir.exists() else ROOT_DIR / "data")


def _confirm_target_is_safe(target: DatabaseStorageBackend, *, force: bool) -> tuple[list[dict[str, Any]], dict[str, Any]]:
    existing_auth_keys = target.load_auth_keys()
    existing_shop_state = target.load_shop_state()
    if force:
        return existing_auth_keys, existing_shop_state
    if existing_auth_keys or existing_shop_state:
        raise RuntimeError(
            "Target shared user database already has auth_keys or shop_state. "
            "Use --merge to append/update safely, or --force to replace the target data."
        )
    return existing_auth_keys, existing_shop_state


def _merge_auth_keys(existing: list[dict[str, Any]], incoming: list[dict[str, Any]]) -> list[dict[str, Any]]:
    merged: dict[str, dict[str, Any]] = {}
    for item in existing:
        item_id = str(item.get("id") or "").strip()
        if item_id:
            merged[item_id] = dict(item)
    for item in incoming:
        item_id = str(item.get("id") or "").strip()
        if item_id:
            merged[item_id] = dict(item)
    return list(merged.values())


def _merge_shop_state(existing: dict[str, Any], incoming: dict[str, Any]) -> dict[str, Any]:
    existing_codes = existing.get("codes") if isinstance(existing.get("codes"), list) else []
    incoming_codes = incoming.get("codes") if isinstance(incoming.get("codes"), list) else []
    existing_ledger = existing.get("ledger") if isinstance(existing.get("ledger"), list) else []
    incoming_ledger = incoming.get("ledger") if isinstance(incoming.get("ledger"), list) else []

    codes_by_id: dict[str, dict[str, Any]] = {}
    for item in [*existing_codes, *incoming_codes]:
        if not isinstance(item, dict):
            continue
        item_id = str(item.get("id") or item.get("code_hash") or "").strip()
        if item_id:
            codes_by_id[item_id] = dict(item)

    ledger_by_id: dict[str, dict[str, Any]] = {}
    for item in [*existing_ledger, *incoming_ledger]:
        if not isinstance(item, dict):
            continue
        item_id = str(item.get("id") or "").strip()
        if item_id:
            ledger_by_id[item_id] = dict(item)

    return {
        "codes": list(codes_by_id.values()),
        "ledger": sorted(ledger_by_id.values(), key=lambda item: str(item.get("time") or "")),
    }


def main() -> int:
    parser = argparse.ArgumentParser(
        description="Migrate users, credits, WeChat bindings, redeem codes, and redemption history to SHARED_USER_DATABASE_URL.",
    )
    parser.add_argument("--merge", action="store_true", help="Merge source data into target instead of requiring an empty target.")
    parser.add_argument("--force", action="store_true", help="Replace target auth_keys and shop_state with source data.")
    parser.add_argument("--dry-run", action="store_true", help="Show what would be migrated without writing target data.")
    args = parser.parse_args()

    target_url = str(os.getenv("SHARED_USER_DATABASE_URL") or "").strip()
    if not target_url:
        raise RuntimeError("SHARED_USER_DATABASE_URL is required.")

    source = create_storage_backend(_data_dir())
    target = DatabaseStorageBackend(target_url)

    source_auth_keys = source.load_auth_keys()
    source_shop_state = source.load_shop_state()
    existing_auth_keys, existing_shop_state = _confirm_target_is_safe(target, force=args.force or args.merge)

    if args.merge and not args.force:
        target_auth_keys = _merge_auth_keys(existing_auth_keys, source_auth_keys)
        target_shop_state = _merge_shop_state(existing_shop_state, source_shop_state)
    else:
        target_auth_keys = source_auth_keys
        target_shop_state = source_shop_state

    code_count = len(target_shop_state.get("codes") or []) if isinstance(target_shop_state, dict) else 0
    ledger_count = len(target_shop_state.get("ledger") or []) if isinstance(target_shop_state, dict) else 0
    print(
        "[migrate-user-storage] prepared: "
        f"auth_keys={len(target_auth_keys)}, codes={code_count}, ledger={ledger_count}, "
        f"mode={'dry-run' if args.dry_run else 'merge' if args.merge and not args.force else 'replace'}"
    )

    if args.dry_run:
        return 0

    target.save_auth_keys(target_auth_keys)
    target.save_shop_state(target_shop_state if isinstance(target_shop_state, dict) else {})
    print("[migrate-user-storage] migration completed.")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())