from __future__ import annotations

from datetime import datetime
from typing import Optional

from sqlalchemy import Boolean, DateTime, ForeignKey, Index, Integer, String, Text, func
from sqlalchemy.orm import Mapped, mapped_column

from app.db.base import Base


class TimestampMixin:
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
        onupdate=func.now(),
    )


class User(TimestampMixin, Base):
    __tablename__ = "users"

    id: Mapped[str] = mapped_column(String, primary_key=True)
    username: Mapped[str] = mapped_column(String, unique=True, nullable=False)
    password_hash: Mapped[str] = mapped_column(String, nullable=False)


class AuthSession(TimestampMixin, Base):
    __tablename__ = "auth_sessions"
    __table_args__ = (
        Index("idx_auth_sessions_user_status", "user_id", "revoked_at", "expires_at"),
        Index("idx_auth_sessions_token_hash", "token_hash", unique=True),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    user_id: Mapped[str] = mapped_column(String, ForeignKey("users.id"), nullable=False)
    token_hash: Mapped[str] = mapped_column(String, nullable=False)
    expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    revoked_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)


class Directory(TimestampMixin, Base):
    __tablename__ = "directories"
    __table_args__ = (
        Index("idx_directories_parent_id", "parent_id"),
        Index("idx_directories_path_key", "path_key"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    parent_id: Mapped[Optional[str]] = mapped_column(
        String,
        ForeignKey("directories.id"),
        nullable=True,
    )
    name: Mapped[str] = mapped_column(String, nullable=False)
    path_key: Mapped[str] = mapped_column(String, unique=True, nullable=False)
    deleted_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)


class FileEntry(TimestampMixin, Base):
    __tablename__ = "file_entries"
    __table_args__ = (
        Index("idx_file_entries_directory_name", "directory_id", "name", "is_deleted", unique=True),
        Index("idx_file_entries_current_version_id", "current_version_id"),
        Index("idx_file_entries_deleted_at", "deleted_at"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    directory_id: Mapped[str] = mapped_column(
        String,
        ForeignKey("directories.id"),
        nullable=False,
    )
    name: Mapped[str] = mapped_column(String, nullable=False)
    mime_type: Mapped[Optional[str]] = mapped_column(String, nullable=True)
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    current_version_id: Mapped[Optional[str]] = mapped_column(String, nullable=True)
    is_deleted: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False, server_default="0")
    deleted_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)


class FileVersion(Base):
    __tablename__ = "file_versions"
    __table_args__ = (
        Index("idx_file_versions_file_entry_id", "file_entry_id"),
        Index("idx_file_versions_content_hash", "content_hash"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    file_entry_id: Mapped[str] = mapped_column(
        String,
        ForeignKey("file_entries.id"),
        nullable=False,
    )
    content_hash: Mapped[str] = mapped_column(String, nullable=False)
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    storage_layout: Mapped[str] = mapped_column(String, nullable=False)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
    )


class Blob(Base):
    __tablename__ = "blobs"
    __table_args__ = (
        Index("idx_blobs_file_version_index", "file_version_id", "blob_index", unique=True),
        Index("idx_blobs_content_hash", "content_hash"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    file_version_id: Mapped[str] = mapped_column(
        String,
        ForeignKey("file_versions.id"),
        nullable=False,
    )
    blob_index: Mapped[int] = mapped_column(Integer, nullable=False)
    kind: Mapped[str] = mapped_column(String, nullable=False)
    content_hash: Mapped[str] = mapped_column(String, nullable=False)
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    logical_offset: Mapped[int] = mapped_column(Integer, nullable=False, default=0, server_default="0")
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
    )


class Backend(TimestampMixin, Base):
    __tablename__ = "backends"
    __table_args__ = (
        Index("idx_backends_enabled", "is_enabled"),
        Index("idx_backends_priority", "write_priority", "read_priority"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    name: Mapped[str] = mapped_column(String, unique=True, nullable=False)
    type: Mapped[str] = mapped_column(String, nullable=False)
    stability_class: Mapped[str] = mapped_column(String, nullable=False)
    read_priority: Mapped[int] = mapped_column(Integer, nullable=False)
    write_priority: Mapped[int] = mapped_column(Integer, nullable=False)
    is_enabled: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True, server_default="1")
    config_json: Mapped[str] = mapped_column(Text, nullable=False)
    capacity_hint_bytes: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
    last_health_status: Mapped[Optional[str]] = mapped_column(String, nullable=True)
    last_health_checked_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)


class PlacementPolicy(TimestampMixin, Base):
    __tablename__ = "placement_policies"
    __table_args__ = (
        Index("idx_placement_policies_file_class", "file_class", unique=True),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    file_class: Mapped[str] = mapped_column(String, nullable=False)
    require_local: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True, server_default="1")
    stable_replica_count: Mapped[int] = mapped_column(Integer, nullable=False, default=1, server_default="1")
    opportunistic_replica_count: Mapped[int] = mapped_column(Integer, nullable=False, default=0, server_default="0")
    preferred_backend_ids_json: Mapped[str] = mapped_column(Text, nullable=False, default="[]", server_default="[]")
    excluded_backend_ids_json: Mapped[str] = mapped_column(Text, nullable=False, default="[]", server_default="[]")
    max_non_local_size_bytes: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)


class BlobReplica(TimestampMixin, Base):
    __tablename__ = "blob_replicas"
    __table_args__ = (
        Index("idx_blob_replicas_blob_backend", "blob_id", "backend_id", unique=True),
        Index("idx_blob_replicas_backend_status", "backend_id", "status"),
        Index("idx_blob_replicas_storage_key", "storage_key"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    blob_id: Mapped[str] = mapped_column(String, ForeignKey("blobs.id"), nullable=False)
    backend_id: Mapped[str] = mapped_column(String, ForeignKey("backends.id"), nullable=False)
    storage_key: Mapped[str] = mapped_column(String, nullable=False)
    status: Mapped[str] = mapped_column(String, nullable=False)
    etag: Mapped[Optional[str]] = mapped_column(String, nullable=True)
    checksum: Mapped[Optional[str]] = mapped_column(String, nullable=True)
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    last_verified_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)


class UploadSession(TimestampMixin, Base):
    __tablename__ = "upload_sessions"
    __table_args__ = (
        Index("idx_upload_sessions_status", "status"),
        Index("idx_upload_sessions_updated_at", "updated_at"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    directory_id: Mapped[Optional[str]] = mapped_column(String, ForeignKey("directories.id"), nullable=True)
    filename: Mapped[Optional[str]] = mapped_column(String, nullable=True)
    total_size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    received_size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    status: Mapped[str] = mapped_column(String, nullable=False)
    temp_path: Mapped[str] = mapped_column(String, nullable=False)
    tus_upload_url: Mapped[Optional[str]] = mapped_column(String, nullable=True)
    upload_metadata_json: Mapped[Optional[str]] = mapped_column(Text, nullable=True)


class UploadSessionPart(TimestampMixin, Base):
    __tablename__ = "upload_session_parts"
    __table_args__ = (
        Index("idx_upload_session_parts_unique", "upload_session_id", "part_number", unique=True),
        Index("idx_upload_session_parts_upload_id", "upload_session_id"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    upload_session_id: Mapped[str] = mapped_column(
        String,
        ForeignKey("upload_sessions.id"),
        nullable=False,
    )
    part_number: Mapped[int] = mapped_column(Integer, nullable=False)
    byte_offset: Mapped[int] = mapped_column(Integer, nullable=False)
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    checksum: Mapped[Optional[str]] = mapped_column(String, nullable=True)
    status: Mapped[str] = mapped_column(String, nullable=False)


class Job(TimestampMixin, Base):
    __tablename__ = "jobs"
    __table_args__ = (
        Index("idx_jobs_status_run_after", "status", "run_after"),
        Index("idx_jobs_kind_status", "kind", "status"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    kind: Mapped[str] = mapped_column(String, nullable=False)
    status: Mapped[str] = mapped_column(String, nullable=False)
    payload_json: Mapped[str] = mapped_column(Text, nullable=False)
    attempt_count: Mapped[int] = mapped_column(Integer, nullable=False, default=0, server_default="0")
    max_attempts: Mapped[int] = mapped_column(Integer, nullable=False, default=5, server_default="5")
    run_after: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    last_error: Mapped[Optional[str]] = mapped_column(Text, nullable=True)


class PreviewArtifact(TimestampMixin, Base):
    __tablename__ = "preview_artifacts"
    __table_args__ = (
        Index("idx_preview_artifacts_version_type", "file_version_id", "artifact_type", unique=True),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    file_version_id: Mapped[str] = mapped_column(String, ForeignKey("file_versions.id"), nullable=False)
    artifact_type: Mapped[str] = mapped_column(String, nullable=False)
    blob_id: Mapped[str] = mapped_column(String, ForeignKey("blobs.id"), nullable=False)
    status: Mapped[str] = mapped_column(String, nullable=False)


class CacheEntry(TimestampMixin, Base):
    __tablename__ = "cache_entries"
    __table_args__ = (
        Index("idx_cache_entries_blob_id", "blob_id"),
        Index("idx_cache_entries_last_accessed_at", "last_accessed_at"),
        Index("idx_cache_entries_expires_at", "expires_at"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    blob_id: Mapped[str] = mapped_column(String, ForeignKey("blobs.id"), nullable=False)
    local_path: Mapped[str] = mapped_column(String, nullable=False)
    cache_kind: Mapped[str] = mapped_column(String, nullable=False)
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    status: Mapped[str] = mapped_column(String, nullable=False)
    last_accessed_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    expires_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)