from __future__ import annotations

from enum import StrEnum
from typing import Any, Literal

from pydantic import BaseModel, ConfigDict, Field, field_validator, model_validator

from app.modules.data_process.constants import MAX_QA_PAIRS_PER_ITEM


def _config_value(config: dict[str, Any], snake_name: str, camel_name: str, default: Any) -> Any:
    if snake_name in config:
        return config[snake_name]
    return config.get(camel_name, default)


def _validate_process_config(config: dict[str, Any]) -> None:
    chunk_method = _config_value(config, "chunk_method", "chunkMethod", "layout_hybrid")
    if not isinstance(chunk_method, str) or chunk_method not in {
        "layout_hybrid",
        "semantic",
        "fixed",
    }:
        raise ValueError("chunk_method must be one of: layout_hybrid, semantic, fixed")

    semantic_percentile = _config_value(
        config,
        "semantic_breakpoint_percentile",
        "semanticBreakpointPercentile",
        95,
    )
    if (
        isinstance(semantic_percentile, bool)
        or not isinstance(semantic_percentile, int)
        or not 1 <= semantic_percentile <= 99
    ):
        raise ValueError("semantic_breakpoint_percentile must be an integer in [1, 99]")

    split = _config_value(config, "dataset_split", "datasetSplit", None)
    if split is not None:
        if not isinstance(split, dict) or set(split) != {"train", "validation", "test"}:
            raise ValueError("dataset_split must contain train, validation and test")
        values = list(split.values())
        if any(isinstance(value, bool) or not isinstance(value, int) for value in values):
            raise ValueError("dataset_split values must be integers")
        if any(value < 0 or value > 100 for value in values) or sum(values) != 100:
            raise ValueError("dataset_split values must be in [0, 100] and total 100")

    chunk_fields = {
        "chunk_size",
        "chunkSize",
        "chunk_overlap",
        "chunkOverlap",
        "min_chunk_size",
        "minChunkSize",
    }
    if chunk_fields.intersection(config):
        chunk_size = _config_value(config, "chunk_size", "chunkSize", 800)
        overlap = _config_value(config, "chunk_overlap", "chunkOverlap", 100)
        minimum = _config_value(config, "min_chunk_size", "minChunkSize", 100)
        if any(
            isinstance(value, bool) or not isinstance(value, int)
            for value in (chunk_size, overlap, minimum)
        ):
            raise ValueError("chunk_size, chunk_overlap and min_chunk_size must be integers")
        if not 16 <= chunk_size <= 32_768:
            raise ValueError("chunk_size must be in [16, 32768]")
        if overlap < 0 or overlap >= chunk_size:
            raise ValueError("chunk_overlap must be in [0, chunk_size)")
        if minimum <= 0 or minimum > chunk_size or overlap + minimum > chunk_size:
            raise ValueError("min_chunk_size and chunk_overlap exceed chunk_size")

    temperature = _config_value(config, "temperature", "temperature", None)
    if temperature is not None:
        if isinstance(temperature, bool) or not isinstance(temperature, (int, float)):
            raise ValueError("temperature must be a number")
        if not 0 <= float(temperature) <= 2:
            raise ValueError("temperature must be in [0, 2]")

    max_tokens = _config_value(config, "max_tokens", "maxTokens", None)
    if max_tokens is not None:
        if isinstance(max_tokens, bool) or not isinstance(max_tokens, int):
            raise ValueError("max_tokens must be an integer")
        if not 1 <= max_tokens <= 32_768:
            raise ValueError("max_tokens must be in [1, 32768]")

    for snake_name, camel_name in (
        ("qa_pairs_per_row", "qaPairsPerRow"),
        ("qa_pairs_per_chunk", "qaPairsPerChunk"),
    ):
        pairs = _config_value(config, snake_name, camel_name, None)
        if pairs is None:
            continue
        if (
            isinstance(pairs, bool)
            or not isinstance(pairs, int)
            or not 1 <= pairs <= MAX_QA_PAIRS_PER_ITEM
        ):
            raise ValueError(
                f"{snake_name} must be an integer in [1, {MAX_QA_PAIRS_PER_ITEM}]"
            )


class DataProcessStatus(StrEnum):
    pending = "pending"
    running = "running"
    completed = "completed"
    failed = "failed"
    stopped = "stopped"


class ProcessType(StrEnum):
    structured = "structured"
    unstructured = "unstructured"
    external = "external"


class DataProcessTaskCreate(BaseModel):
    model_config = ConfigDict(extra="forbid")

    name: str = Field(min_length=1, max_length=150)
    description: str = ""
    process_type: ProcessType
    source_dataset_id: str | None = None
    config: dict[str, Any] = Field(default_factory=dict)

    @field_validator("name")
    @classmethod
    def normalize_name(cls, value: str) -> str:
        value = value.strip()
        if not value:
            raise ValueError("task name cannot be empty")
        return value

    @model_validator(mode="after")
    def validate_config(self) -> "DataProcessTaskCreate":
        _validate_process_config(self.config)
        return self


class DataProcessTaskUpdate(BaseModel):
    model_config = ConfigDict(extra="forbid")

    name: str | None = Field(default=None, min_length=1, max_length=150)
    description: str | None = None
    process_type: ProcessType | None = None
    source_dataset_id: str | None = None
    config: dict[str, Any] | None = None

    @field_validator("name")
    @classmethod
    def normalize_name(cls, value: str | None) -> str | None:
        if value is None:
            return None
        value = value.strip()
        if not value:
            raise ValueError("task name cannot be empty")
        return value

    @model_validator(mode="after")
    def validate_config(self) -> "DataProcessTaskUpdate":
        if self.config is not None:
            _validate_process_config(self.config)
        return self


class DataProcessRegenerateRequest(BaseModel):
    """以一份完整配置准备任务重新生成。

    ``expected_updated_at`` 用于防止详情页的旧快照覆盖其他人刚刚
    保存的配置。重新生成不允许改变处理类型，避免旧源文件在新解析
    规则下被静默误用。
    """

    model_config = ConfigDict(extra="forbid")

    name: str = Field(min_length=1, max_length=150)
    description: str
    process_type: ProcessType
    config: dict[str, Any]
    expected_updated_at: str = Field(min_length=1)

    @field_validator("name")
    @classmethod
    def normalize_name(cls, value: str) -> str:
        value = value.strip()
        if not value:
            raise ValueError("task name cannot be empty")
        return value

    @model_validator(mode="after")
    def validate_config(self) -> "DataProcessRegenerateRequest":
        _validate_process_config(self.config)
        return self


class PreviewBuildRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")

    replace_existing: Literal[True] = True
    source_file_ids: list[str] | None = None
    source_file_id: str | None = None

    @model_validator(mode="after")
    def validate_source_file_selection(self) -> "PreviewBuildRequest":
        if self.source_file_ids is not None and self.source_file_id is not None:
            raise ValueError("source_file_id and source_file_ids cannot be used together")
        values = self.source_file_ids
        if values is None and self.source_file_id is not None:
            values = [self.source_file_id]
        if values is None:
            return self
        normalized = list(dict.fromkeys(str(value).strip() for value in values))
        if not normalized or any(not value for value in normalized):
            raise ValueError("at least one non-empty source file id is required")
        self.source_file_ids = normalized
        self.source_file_id = None
        return self


class PreviewItemCreate(BaseModel):
    model_config = ConfigDict(extra="forbid")

    source_file_id: str | None = None
    original_content: str = ""
    edited_content: str = ""
    source_start: int | None = Field(default=None, ge=0)
    source_end: int | None = Field(default=None, ge=0)
    source_start_line: int | None = Field(default=None, ge=1)
    source_end_line: int | None = Field(default=None, ge=1)

    @model_validator(mode="after")
    def validate_ranges(self) -> "PreviewItemCreate":
        if self.source_start is not None and self.source_end is not None:
            if self.source_end < self.source_start:
                raise ValueError("source_end must be greater than or equal to source_start")
        if self.source_start_line is not None and self.source_end_line is not None:
            if self.source_end_line < self.source_start_line:
                raise ValueError(
                    "source_end_line must be greater than or equal to source_start_line"
                )
        return self


class PreviewItemUpdate(BaseModel):
    model_config = ConfigDict(extra="forbid")

    edited_content: str
    expected_updated_at: str | None = None


class GenerateRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")

    replace_existing: Literal[True] = True


class ExternalSourceRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")

    type: str = Field(min_length=1, max_length=30)
    url: str = Field(min_length=1, max_length=2048)
    auth_mode: Literal["none", "basic"] = "none"
    username: str | None = Field(default=None, max_length=150)
    password: str | None = Field(default=None, max_length=500)
    limit: int = Field(default=1000, ge=1, le=100_000)


class ExternalPullRequest(ExternalSourceRequest):
    query: str | None = Field(default=None, max_length=20_000)
    file_name: str = Field(default="external-data.jsonl", min_length=1, max_length=255)

    @field_validator("file_name")
    @classmethod
    def validate_file_name(cls, value: str) -> str:
        name = value.strip()
        if not name.lower().endswith((".jsonl", ".ndjson")):
            raise ValueError("external pull file_name must end with .jsonl or .ndjson")
        return name


class ResultUpdate(BaseModel):
    model_config = ConfigDict(extra="forbid")

    instruction: str | None = None
    input: str | None = None
    output: str | None = None
    expected_updated_at: str | None = None


class DatasetSplit(BaseModel):
    model_config = ConfigDict(extra="forbid")

    train: int = Field(default=80, ge=0, le=100)
    validation: int = Field(default=10, ge=0, le=100)
    test: int = Field(default=10, ge=0, le=100)

    @model_validator(mode="after")
    def validate_total(self) -> "DatasetSplit":
        if self.train + self.validation + self.test != 100:
            raise ValueError("dataset split must total 100")
        return self


class PublishRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")

    dataset_name: str = Field(min_length=1, max_length=150)
    dataset_type: Literal["train", "test", "eval", "val", "other"] = "train"
    storage_type: Literal["local"] = "local"
    split: DatasetSplit = Field(default_factory=DatasetSplit)
    format: Literal["alpaca_jsonl", "jsonl"] = "alpaca_jsonl"
    description: str = ""

    @field_validator("dataset_name")
    @classmethod
    def normalize_dataset_name(cls, value: str) -> str:
        value = value.strip()
        if not value:
            raise ValueError("dataset name cannot be empty")
        return value