import os
from dataclasses import dataclass


def get_env_str(key: str, default: str) -> str:
    return os.getenv(key, default)


def get_env_int(key: str, default: int) -> int:
    val = os.getenv(key)
    if val is None or not val.strip():
        return default
    return int(val)


def get_env_float(key: str, default: float) -> float:
    val = os.getenv(key)
    if val is None or not val.strip():
        return default
    return float(val)


@dataclass(frozen=True)
class APIConfig:
    host: str = get_env_str("API_HOST", "0.0.0.0")
    port: int = get_env_int("API_PORT", 8000)
    queue_max_size: int = get_env_int("API_QUEUE_MAX_SIZE", 10000)
    worker_stats_url: str = get_env_str(
        "WORKER_STATS_URL", "http://worker:8001/internal/stats"
    )


@dataclass(frozen=True)
class WorkerConfig:
    instance_id: str = get_env_str("WORKER_INSTANCE", "worker-1")
    stats_host: str = get_env_str("WORKER_STATS_HOST", "0.0.0.0")
    stats_port: int = get_env_int("WORKER_STATS_PORT", 8001)


@dataclass(frozen=True)
class KafkaConfig:
    bootstrap_servers: str = get_env_str("KAFKA_BOOTSTRAP_SERVERS", "localhost:9092")
    raw_topic: str = get_env_str("KAFKA_RAW_TOPIC", "cdr.raw")
    dlq_topic: str = get_env_str("KAFKA_DLQ_TOPIC", "cdr.raw.dlq")
    consumer_group: str = get_env_str("KAFKA_CONSUMER_GROUP", "cdr-processing-group")
    auto_offset_reset: str = get_env_str("KAFKA_AUTO_OFFSET_RESET", "earliest")


@dataclass(frozen=True)
class ClickHouseConfig:
    host: str = get_env_str("CLICKHOUSE_HOST", "localhost")
    port: int = get_env_int("CLICKHOUSE_PORT", 8123)
    user: str = get_env_str("CLICKHOUSE_USER", "default")
    password: str = get_env_str("CLICKHOUSE_PASSWORD", "")
    database: str = get_env_str("CLICKHOUSE_DATABASE", "telecom")
    table: str = get_env_str("CLICKHOUSE_TABLE", "cdr_records")


@dataclass(frozen=True)
class BatchConfig:
    size: int = get_env_int("BATCH_SIZE", 1000)
    flush_interval_seconds: float = get_env_float("BATCH_FLUSH_INTERVAL_SECONDS", 2.0)


@dataclass(frozen=True)
class RetryConfig:
    max_attempts: int = get_env_int("CH_RETRY_MAX_ATTEMPTS", 3)
    initial_delay_ms: int = get_env_int("CH_RETRY_INITIAL_DELAY_MS", 500)
    backoff_factor: float = get_env_float("CH_RETRY_BACKOFF_FACTOR", 2.0)


@dataclass(frozen=True)
class AppConfig:
    api: APIConfig = APIConfig()
    worker: WorkerConfig = WorkerConfig()
    kafka: KafkaConfig = KafkaConfig()
    clickhouse: ClickHouseConfig = ClickHouseConfig()
    batch: BatchConfig = BatchConfig()
    retry: RetryConfig = RetryConfig()
    log_level: str = get_env_str("LOG_LEVEL", "INFO")


config = AppConfig()