"""
Pydantic models for the Data Cleaning RL Environment.

Defines the typed action, observation, and state structures.
Inherits from openenv base types so the openenv SDK (WebSocket protocol,
from_docker_image, GenericEnvClient) works out of the box.
"""

from __future__ import annotations

from enum import Enum
from typing import Any, Dict, List, Optional

from pydantic import Field

from openenv.core.env_server.types import (
    Action as OEAction,
    Observation as OEObservation,
)


# ----------------------
# Action enums
# -----------------------


class ActionType(str, Enum):
    fill_missing = "fill_missing"
    drop_duplicates = "drop_duplicates"
    fix_type = "fix_type"
    normalize = "normalize"
    drop_outliers = "drop_outliers"
    fix_schema_violation = "fix_schema_violation"
    done = "done"
    rename_column = "rename_column"
    cast_datetime = "cast_datetime"
    deduplicate_fuzzy = "deduplicate_fuzzy"
    split_column = "split_column"
    merge_columns = "merge_columns"
    fix_format_regex = "fix_format_regex"
    standardize_categories = "standardize_categories"
    undo = "undo"
    profile_column = "profile_column"


class FillStrategy(str, Enum):
    mean = "mean"
    median = "median"
    mode = "mode"
    constant = "constant"


class DType(str, Enum):
    int = "int"
    float = "float"
    str = "str"


class OutlierMethod(str, Enum):
    iqr = "iqr"
    zscore = "zscore"


class SchemaConstraint(str, Enum):
    non_negative = "non_negative"
    clamp_range = "clamp_range"


class MergeStrategy(str, Enum):
    concat = "concat"
    first_non_null = "first_non_null"
    sum = "sum"


# ----------------------
# Action model — inherits from openenv.Action
# -----------------------


class CleaningAction(OEAction):
    """A single cleaning action issued by the agent."""

    model_config = {"extra": "allow"}

    action_type: ActionType = Field(
        ..., description="Type of cleaning action to perform.",
    )
    column: Optional[str] = Field(
        None, description="Target column name.",
    )
    strategy: Optional[FillStrategy] = Field(
        None, description="Fill strategy for fill_missing action.",
    )
    dtype: Optional[DType] = Field(
        None, description="Target dtype for fix_type action.",
    )
    method: Optional[OutlierMethod] = Field(
        None, description="Outlier detection method for drop_outliers action.",
    )
    constraint: Optional[SchemaConstraint] = Field(
        None, description="Constraint type for fix_schema_violation action.",
    )
    constant_value: Optional[Any] = Field(
        None, description="Constant fill value for fill_missing with strategy=constant.",
    )
    new_name: Optional[str] = Field(
        None, description="New column name for rename_column action.",
    )
    datetime_format: Optional[str] = Field(
        None, description="DateTime format string for cast_datetime action.",
    )
    threshold: Optional[float] = Field(
        None, description="Similarity threshold for deduplicate_fuzzy (0.0-1.0).",
    )
    delimiter: Optional[str] = Field(
        None, description="Delimiter string for split_column action.",
    )
    column2: Optional[str] = Field(
        None, description="Second column name for merge_columns action.",
    )
    merge_strategy: Optional[MergeStrategy] = Field(
        None, description="Merge strategy for merge_columns.",
    )
    pattern: Optional[str] = Field(
        None, description="Regex pattern for fix_format_regex action.",
    )
    replacement: Optional[str] = Field(
        None, description="Replacement string for fix_format_regex action.",
    )


# ---------------
# Observation — inherits from openenv.Observation
# -------------------


class ColumnIssues(OEObservation):
    """Per-column data quality issues detected in the current state."""

    model_config = {"extra": "allow"}

    missing_count: int = Field(0, description="Number of missing (NaN) values.")
    missing_pct: float = Field(0.0, description="Fraction of missing values [0, 1].")
    type_errors: int = Field(0, description="Cells that cannot be parsed as expected dtype.")
    outlier_count: int = Field(0, description="Outliers detected via IQR rule.")
    has_duplicates: bool = Field(False, description="True if dataset has duplicate rows.")
    format_violation_count: int = Field(0, description="Values not matching expected format.")
    encoding_issue_count: int = Field(0, description="Values with unexpected non-ASCII chars.")
    semantic_duplicate_count: int = Field(0, description="Near-duplicate distinct string values.")


class ColumnStats(OEObservation):
    """Compact statistical summary for a column."""

    model_config = {"extra": "allow"}

    mean: Optional[float] = None
    std: Optional[float] = None
    null_count: int = 0
    unique_count: int = 0


class Observation(OEObservation):
    """Observation returned by reset() and step()."""

    model_config = {"extra": "allow"}

    task: str = Field("", description="Task tier: 'easy', 'medium', 'hard', or 'expert'.")
    step: int = Field(0, description="Current step number (0-indexed).")
    max_steps: int = Field(0, description="Maximum steps allowed in this episode.")
    columns: List[str] = Field(default_factory=list, description="Column names in the dataset.")
    column_issues: Dict[str, Any] = Field(
        default_factory=dict, description="Data quality issues per column.",
    )
    column_stats: Dict[str, Any] = Field(
        default_factory=dict, description="Compact statistics per column.",
    )
    sample_rows: List[Dict[str, Any]] = Field(
        default_factory=list, description="Up to 5 sampled rows.",
    )
    action_history: List[Dict[str, Any]] = Field(
        default_factory=list, description="Last 5 actions with rewards.",
    )
    budget_remaining: Optional[float] = Field(
        None, description="Remaining action budget (0.0-1.0).",
    )
    profile_result: Optional[Dict[str, Any]] = Field(
        None, description="Extended column statistics from last profile_column.",
    )


# ----------------
# Episode state
# --------------------


class EpisodeState(OEObservation):
    """Metadata about the current episode."""

    model_config = {"extra": "allow"}

    episode_id: str = Field("", description="Unique episode identifier (UUID).")
    task: str = Field("", description="Task tier.")
    step: int = Field(0, description="Current step number.")
    max_steps: int = Field(0, description="Maximum steps allowed.")
    score: Optional[float] = Field(
        None, description="Final grader score (0.0-1.0).",
    )