"""Immutable records emitted by the Evidence preprocessing pipeline."""

from datetime import UTC, datetime

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

from tht.ports.evidence import _reject_credentials


class _CanonicalValue(BaseModel):
    model_config = ConfigDict(frozen=True, extra="forbid")


class _WithMetadata(_CanonicalValue):
    metadata: dict[str, JsonValue] = Field(default_factory=dict)

    @field_validator("metadata")
    @classmethod
    def metadata_has_no_credentials(cls, value: dict[str, JsonValue]) -> dict[str, JsonValue]:
        _reject_credentials(value)
        return value


class CanonicalDocument(_WithMetadata):
    document_id: str = Field(min_length=1)
    source_id: str = Field(min_length=1)
    source_uri: str = Field(min_length=1)
    source_fingerprint: str = Field(min_length=1)
    content_hash: str = Field(min_length=1)
    title: str = ""
    content: str
    media_type: str = "text/plain"
    modified_at: datetime | None = None
    pipeline_version: str = Field(min_length=1)


class CanonicalChunk(_WithMetadata):
    chunk_id: str = Field(min_length=1)
    document_id: str = Field(min_length=1)
    ordinal: int = Field(ge=0)
    content: str
    content_hash: str = Field(min_length=1)
    source_uri: str = Field(min_length=1)
    pipeline_version: str = Field(min_length=1)


class CorpusManifest(_WithMetadata):
    """Description of one publishable canonical/vector generation."""

    schema_version: int = Field(default=1, ge=1)
    manifest_id: str | None = None
    created_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
    pipeline_version: str = Field(default="1", min_length=1)
    embedding_model: str | None = None
    embedding_dimensions: int | None = Field(default=None, gt=0)
    vector_generation: str | None = None
    documents: list[CanonicalDocument] = Field(default_factory=list)
    chunks: list[CanonicalChunk] = Field(default_factory=list)

    @model_validator(mode="after")
    def embedding_fields_are_complete(self) -> "CorpusManifest":
        if (self.embedding_model is None) != (self.embedding_dimensions is None):
            raise ValueError("embedding_model and embedding_dimensions must be set together")
        return self