"""Configuration management using Pydantic settings."""
from pydantic_settings import BaseSettings
from pydantic import ConfigDict
from typing import Optional
import os


class MySQLConfig(BaseSettings):
    """MySQL source database configuration."""
    model_config = ConfigDict(
        env_prefix="MYSQL_",
        case_sensitive=False,
        extra="ignore",
        env_file=".env",
        env_file_encoding="utf-8"
    )

    host: str
    port: int
    user: str
    password: str
    database: str


class PostgreSQLConfig(BaseSettings):
    """PostgreSQL target database configuration."""
    model_config = ConfigDict(
        env_prefix="POSTGRES_",
        case_sensitive=False,
        extra="ignore",
        env_file=".env",
        env_file_encoding="utf-8"
    )

    host: str
    port: int
    user: str
    password: str
    database: str


class MigrationSettings(BaseSettings):
    """Migration settings."""
    model_config = ConfigDict(
        case_sensitive=False,
        extra="ignore",
        env_file=".env",
        env_file_encoding="utf-8"
    )

    batch_size: int = 10000
    consolidation_group_limit: int = 10000
    log_level: str = "INFO"
    dry_run: bool = False


class BenchmarkSettings(BaseSettings):
    """Benchmark settings."""
    model_config = ConfigDict(
        env_prefix="BENCHMARK_",
        case_sensitive=False,
        extra="ignore",
        env_file=".env",
        env_file_encoding="utf-8"
    )

    output_dir: str = "benchmark_results"
    iterations: int = 5


class Settings(BaseSettings):
    """All application settings."""
    model_config = ConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        case_sensitive=False,
        extra="ignore"
    )

    mysql: MySQLConfig
    postgres: PostgreSQLConfig
    migration: MigrationSettings
    benchmark: BenchmarkSettings

    @classmethod
    def from_env(cls):
        """Load settings from environment variables."""
        return cls(
            mysql=MySQLConfig(),
            postgres=PostgreSQLConfig(),
            migration=MigrationSettings(),
            benchmark=BenchmarkSettings(),
        )


# Lazy load settings
_settings: Optional[Settings] = None


def get_settings() -> Settings:
    """Get application settings, loading from .env if necessary."""
    global _settings
    if _settings is None:
        _settings = Settings.from_env()
    return _settings


# Schema transformation definitions
RAWDATACOR_COLUMNS = {
    "val_columns": ["Val0", "Val1", "Val2", "Val3", "Val4", "Val5", "Val6", "Val7", "Val8", "Val9", "ValA", "ValB", "ValC", "ValD", "ValE", "ValF"],
    "unit_columns": ["Val0_unitmisure", "Val1_unitmisure", "Val2_unitmisure", "Val3_unitmisure", "Val4_unitmisure", "Val5_unitmisure", "Val6_unitmisure", "Val7_unitmisure", "Val8_unitmisure", "Val9_unitmisure", "ValA_unitmisure", "ValB_unitmisure", "ValC_unitmisure", "ValD_unitmisure", "ValE_unitmisure", "ValF_unitmisure"],
}

ELABDATADISP_MEASUREMENT_FIELDS = {
    "shifts": ["XShift", "YShift", "ZShift", "HShift", "HShiftDir", "HShift_local"],
    "coordinates": ["X", "Y", "Z", "Xstar", "Zstar"],
    "kinematics": ["speed", "speed_local", "acceleration", "acceleration_local"],
    "sensors": ["T_node", "load_value", "water_level", "pressure"],
    "calculated": ["AlfaX", "AlfaY", "Area"],
}

ELABDATADISP_FIELD_MAPPING = {
    # shifts mapping (source -> (category, key))
    "XShift": ("shifts", "x"),
    "YShift": ("shifts", "y"),
    "ZShift": ("shifts", "z"),
    "HShift": ("shifts", "h"),
    "HShiftDir": ("shifts", "h_dir"),
    "HShift_local": ("shifts", "h_local"),
    # coordinates mapping
    "X": ("coordinates", "x"),
    "Y": ("coordinates", "y"),
    "Z": ("coordinates", "z"),
    "Xstar": ("coordinates", "x_star"),
    "Zstar": ("coordinates", "z_star"),
    # kinematics mapping
    "speed": ("kinematics", "speed"),
    "speed_local": ("kinematics", "speed_local"),
    "acceleration": ("kinematics", "acceleration"),
    "acceleration_local": ("kinematics", "acceleration_local"),
    # sensors mapping
    "T_node": ("sensors", "t_node"),
    "load_value": ("sensors", "load_value"),
    "water_level": ("sensors", "water_level"),
    "pressure": ("sensors", "pressure"),
    # calculated mapping
    "AlfaX": ("calculated", "alfa_x"),
    "AlfaY": ("calculated", "alfa_y"),
    "Area": ("calculated", "area"),
}

# PostgreSQL Partition years (from both tables)
PARTITION_YEARS = list(range(2014, 2032))  # 2014-2031

# Table configurations - support both uppercase and lowercase keys
_rawdatacor_config = {
    "mysql_table": "RAWDATACOR",
    "postgres_table": "rawdatacor",
    "primary_key": "id",
    "postgres_pk": "id",  # Primary key column name in PostgreSQL
    "partition_key": "event_timestamp",
}
_elabdatadisp_config = {
    "mysql_table": "ELABDATADISP",
    "postgres_table": "elabdatadisp",
    "primary_key": "idElabData",
    "postgres_pk": "id_elab_data",  # Primary key column name in PostgreSQL
    "partition_key": "event_timestamp",
}

TABLE_CONFIGS = {
    "rawdatacor": _rawdatacor_config,
    "RAWDATACOR": _rawdatacor_config,
    "elabdatadisp": _elabdatadisp_config,
    "ELABDATADISP": _elabdatadisp_config,
}