"""SQLAlchemy ORM models mirroring the authoritative DDL in SPEC §4.

The Alembic initial migration is generated to match these models exactly.
Invariant I-7: every table carrying user data has an indexed ``user_id``.
"""

from __future__ import annotations

import datetime as dt
import uuid
from typing import Any

from sqlalchemy import (
    BigInteger,
    CheckConstraint,
    ForeignKey,
    Index,
    Integer,
    Text,
    UniqueConstraint,
    text,
)
from sqlalchemy.dialects.postgresql import (
    ARRAY,
    BYTEA,
    CITEXT,
    JSONB,
    TIMESTAMP,
    TSVECTOR,
    UUID,
)
from sqlalchemy.orm import Mapped, mapped_column

from app.db import Base


def _uuid_pk() -> Mapped[uuid.UUID]:
    return mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        server_default=text("gen_random_uuid()"),
    )


def _now() -> Mapped[dt.datetime]:
    return mapped_column(TIMESTAMP(timezone=True), nullable=False, server_default=text("now()"))


class AppSettings(Base):
    """Instance-wide settings, exactly one row (id = 1).

    Distinct from :func:`app.config.get_settings`, which is deployment environment
    read at boot; these are options an administrator changes at runtime from the
    admin panel. Locking this row serialises the registration decision below.
    """

    __tablename__ = "app_settings"
    __table_args__ = (
        CheckConstraint("id = 1", name="ck_app_settings_singleton"),
        CheckConstraint("default_quota_bytes > 0", name="ck_app_settings_quota_positive"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True, server_default=text("1"))
    # Whether POST /auth/register accepts new users. Closed automatically once the
    # first account (the administrator) is created; an admin reopens it later.
    registration_open: Mapped[bool] = mapped_column(nullable=False, server_default=text("false"))
    # Quota handed to the NEXT user created. Existing users keep whatever
    # users.quota_bytes already says — changing this never resizes a mailbox.
    default_quota_bytes: Mapped[int] = mapped_column(
        BigInteger, nullable=False, server_default=text("5368709120")
    )
    # Outgoing system mail (password-reset links): the SMTP account the server
    # sends from. The password is vault-encrypted (like Account.secret_ct).
    smtp_host: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    smtp_port: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("587"))
    smtp_security: Mapped[str] = mapped_column(
        Text, nullable=False, server_default=text("'starttls'")
    )  # starttls | ssl | none
    smtp_username: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    smtp_secret_ct: Mapped[bytes | None] = mapped_column(BYTEA)
    smtp_from: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    # Where users reach the app, e.g. https://mail.example.com — reset links are
    # built from this, never from the request's Host header.
    public_url: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    updated_at: Mapped[dt.datetime] = _now()


class User(Base):
    __tablename__ = "users"

    id: Mapped[uuid.UUID] = _uuid_pk()
    handle: Mapped[str] = mapped_column(CITEXT, unique=True, nullable=False)
    password_hash: Mapped[str] = mapped_column(Text, nullable=False)
    totp_secret: Mapped[bytes | None] = mapped_column(BYTEA)
    recovery_email: Mapped[str | None] = mapped_column(CITEXT)
    settings: Mapped[dict[str, object]] = mapped_column(
        JSONB, nullable=False, server_default=text("'{}'")
    )
    # Storage quota in bytes; per-user so an admin can override it later.
    # Default 5 GiB (5 * 1024^3).
    quota_bytes: Mapped[int] = mapped_column(
        BigInteger, nullable=False, server_default=text("5368709120")
    )
    # The first account created on a fresh install bootstraps as administrator;
    # the admin panel can grant it to others later.
    is_admin: Mapped[bool] = mapped_column(nullable=False, server_default=text("false"))
    # Set while an administrator has blocked the account (no sign-in, sessions
    # refused); NULL when not blocked.
    blocked_at: Mapped[dt.datetime | None] = mapped_column(TIMESTAMP(timezone=True))
    created_at: Mapped[dt.datetime] = _now()


class Account(Base):
    __tablename__ = "accounts"
    __table_args__ = (UniqueConstraint("user_id", "email", name="uq_accounts_user_email"),)

    id: Mapped[uuid.UUID] = _uuid_pk()
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
    )
    email: Mapped[str] = mapped_column(CITEXT, nullable=False)
    display_name: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    color: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("'#888888'"))
    # Per-account HTML signature, inserted into new messages (and via compose menu).
    signature: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    imap_config: Mapped[dict[str, object]] = mapped_column(JSONB, nullable=False)
    smtp_config: Mapped[dict[str, object]] = mapped_column(JSONB, nullable=False)
    secret_ct: Mapped[bytes] = mapped_column(BYTEA, nullable=False)
    discovery_src: Mapped[str] = mapped_column(Text, nullable=False)
    state: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("'backfilling'"))
    state_detail: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    # How much history to import (SPEC §12 M2): all | 3months | new. Drives the
    # initial backfill; backfill_total/backfill_done feed the progress UX.
    sync_window: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("'all'"))
    # Whether the Spam/Junk folder is synced (opt-in; SPEC §6.3 folder selection).
    sync_spam: Mapped[bool] = mapped_column(nullable=False, server_default=text("false"))
    backfill_total: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))
    backfill_done: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))
    last_sync_at: Mapped[dt.datetime | None] = mapped_column(TIMESTAMP(timezone=True))
    created_at: Mapped[dt.datetime] = _now()


class Mailbox(Base):
    __tablename__ = "mailboxes"
    __table_args__ = (UniqueConstraint("account_id", "path", name="uq_mailboxes_account_path"),)

    id: Mapped[uuid.UUID] = _uuid_pk()
    account_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("accounts.id", ondelete="CASCADE"), nullable=False
    )
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    path: Mapped[str] = mapped_column(Text, nullable=False)
    special_use: Mapped[str | None] = mapped_column(Text)
    uidvalidity: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))
    highestmodseq: Mapped[int | None] = mapped_column(Integer)
    last_seen_uid: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))


class Thread(Base):
    __tablename__ = "threads"
    __table_args__ = (Index("ix_threads_user_last", "user_id", text("last_message_at DESC")),)

    id: Mapped[uuid.UUID] = _uuid_pk()
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    subject_norm: Mapped[str] = mapped_column(Text, nullable=False)
    snippet: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    participants: Mapped[list[dict[str, str]]] = mapped_column(
        JSONB, nullable=False, server_default=text("'[]'")
    )
    account_ids: Mapped[list[uuid.UUID]] = mapped_column(
        ARRAY(UUID(as_uuid=True)), nullable=False, server_default=text("'{}'")
    )
    message_count: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))
    unread_count: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))
    has_attachments: Mapped[bool] = mapped_column(nullable=False, server_default=text("false"))
    pinned: Mapped[bool] = mapped_column(nullable=False, server_default=text("false"))
    last_message_at: Mapped[dt.datetime] = mapped_column(TIMESTAMP(timezone=True), nullable=False)


class Message(Base):
    __tablename__ = "messages"
    __table_args__ = (
        UniqueConstraint("mailbox_id", "uid", name="uq_messages_mailbox_uid"),
        Index("ix_messages_user_thread", "user_id", "thread_id"),
        Index("ix_messages_account_msgid", "account_id", "message_id_hdr"),
        Index("ix_messages_user_msgid", "user_id", "message_id_hdr"),
        Index("ix_messages_body_indexed", "body_indexed", postgresql_using="gin"),
    )

    id: Mapped[uuid.UUID] = _uuid_pk()
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    account_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("accounts.id", ondelete="CASCADE"), nullable=False
    )
    mailbox_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("mailboxes.id", ondelete="CASCADE"), nullable=False
    )
    # The folder this message was in before being moved to Archive/Trash/Junk, so
    # Restore can return it there (e.g. Sent) instead of the Inbox. NULL otherwise.
    restore_mailbox_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True), ForeignKey("mailboxes.id", ondelete="SET NULL")
    )
    uid: Mapped[int] = mapped_column(Integer, nullable=False)
    thread_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True), ForeignKey("threads.id")
    )
    message_id_hdr: Mapped[str | None] = mapped_column(Text)
    # The real header Message-ID as delivered (kept even when message_id_hdr is
    # synthesized for a cross-account duplicate, §7.1). Identifies one delivery, so
    # the same email fanned out to several accounts collapses to one row in a thread.
    delivery_id: Mapped[str | None] = mapped_column(Text)
    in_reply_to: Mapped[str | None] = mapped_column(Text)
    references_hdr: Mapped[list[str]] = mapped_column(
        ARRAY(Text), nullable=False, server_default=text("'{}'")
    )
    subject: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    from_addr: Mapped[list[dict[str, str]]] = mapped_column(
        JSONB, nullable=False, server_default=text("'[]'")
    )
    to_addr: Mapped[list[dict[str, str]]] = mapped_column(
        JSONB, nullable=False, server_default=text("'[]'")
    )
    cc_addr: Mapped[list[dict[str, str]]] = mapped_column(
        JSONB, nullable=False, server_default=text("'[]'")
    )
    bcc_addr: Mapped[list[dict[str, str]]] = mapped_column(
        JSONB, nullable=False, server_default=text("'[]'")
    )
    date_hdr: Mapped[dt.datetime | None] = mapped_column(TIMESTAMP(timezone=True))
    internal_date: Mapped[dt.datetime] = mapped_column(TIMESTAMP(timezone=True), nullable=False)
    flags: Mapped[list[str]] = mapped_column(
        ARRAY(Text), nullable=False, server_default=text("'{}'")
    )
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))
    has_attachments: Mapped[bool] = mapped_column(nullable=False, server_default=text("false"))
    has_remote_images: Mapped[bool] = mapped_column(nullable=False, server_default=text("false"))
    snippet: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    blob_sha256: Mapped[str] = mapped_column(Text, nullable=False)
    body_indexed: Mapped[str | None] = mapped_column(TSVECTOR)


class BodyPart(Base):
    __tablename__ = "body_parts"

    id: Mapped[uuid.UUID] = _uuid_pk()
    message_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("messages.id", ondelete="CASCADE"), nullable=False
    )
    kind: Mapped[str] = mapped_column(Text, nullable=False)  # text | html_sanitized
    content: Mapped[str] = mapped_column(Text, nullable=False)
    # SPEC §10.4: re-sanitize on render if the sanitizer version changed.
    sanitizer_v: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))


class Attachment(Base):
    __tablename__ = "attachments"

    id: Mapped[uuid.UUID] = _uuid_pk()
    message_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("messages.id", ondelete="CASCADE"), nullable=False
    )
    user_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), nullable=False)
    filename: Mapped[str] = mapped_column(Text, nullable=False)
    mime_type: Mapped[str] = mapped_column(Text, nullable=False)
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    content_id: Mapped[str | None] = mapped_column(Text)
    blob_sha256: Mapped[str] = mapped_column(Text, nullable=False)


class ComposeAttachment(Base):
    """A file uploaded for an outgoing message, referenced by a draft's payload."""

    __tablename__ = "compose_attachments"

    id: Mapped[uuid.UUID] = _uuid_pk()
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    filename: Mapped[str] = mapped_column(Text, nullable=False)
    mime_type: Mapped[str] = mapped_column(Text, nullable=False)
    size_bytes: Mapped[int] = mapped_column(Integer, nullable=False)
    blob_sha256: Mapped[str] = mapped_column(Text, nullable=False)
    created_at: Mapped[dt.datetime] = _now()


class Draft(Base):
    __tablename__ = "drafts"

    id: Mapped[uuid.UUID] = _uuid_pk()
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    account_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("accounts.id", ondelete="CASCADE"), nullable=False
    )
    thread_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True), ForeignKey("threads.id")
    )
    reply_to_message_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True), ForeignKey("messages.id")
    )
    kind: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("'reply'"))
    payload: Mapped[dict[str, object]] = mapped_column(JSONB, nullable=False)
    # UID of the mirrored copy in the account's IMAP Drafts folder (so the draft
    # is visible/continuable on other mail clients). Replaced on each edit.
    imap_uid: Mapped[int | None] = mapped_column(Integer)
    updated_at: Mapped[dt.datetime] = _now()


class Outbox(Base):
    __tablename__ = "outbox"

    id: Mapped[uuid.UUID] = _uuid_pk()
    user_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), nullable=False)
    draft_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), nullable=False)
    state: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("'undo_window'"))
    send_after: Mapped[dt.datetime] = mapped_column(TIMESTAMP(timezone=True), nullable=False)
    error: Mapped[str | None] = mapped_column(Text)


class SavedSearch(Base):
    __tablename__ = "saved_searches"
    __table_args__ = (UniqueConstraint("user_id", "name", name="uq_saved_searches_user_name"),)

    id: Mapped[uuid.UUID] = _uuid_pk()
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    name: Mapped[str] = mapped_column(Text, nullable=False)
    query: Mapped[str] = mapped_column(Text, nullable=False)
    pinned: Mapped[bool] = mapped_column(nullable=False, server_default=text("true"))


class PluginKv(Base):
    """Namespaced key/value store for plugins (SPEC §11 ``plugin_kv``).

    Core-owned infrastructure (not a ``plg_``-prefixed plugin table): every plugin
    gets a slice keyed by (plugin, user_id, key). ``value`` is arbitrary JSON.
    Invariant I-7 (user-data rows carry ``user_id``) holds here too."""

    __tablename__ = "plugin_kv"

    plugin: Mapped[str] = mapped_column(Text, primary_key=True)
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), primary_key=True
    )
    key: Mapped[str] = mapped_column(Text, primary_key=True)
    value: Mapped[Any] = mapped_column(JSONB, nullable=False)


class KnownRecipient(Base):
    __tablename__ = "known_recipients"
    __table_args__ = (
        Index(
            "ix_known_recipients_user_email",
            "user_id",
            text("email text_pattern_ops"),
        ),
    )

    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("users.id", ondelete="CASCADE"),
        primary_key=True,
    )
    email: Mapped[str] = mapped_column(CITEXT, primary_key=True)
    name: Mapped[str] = mapped_column(Text, nullable=False, server_default=text("''"))
    times_used: Mapped[int] = mapped_column(Integer, nullable=False, server_default=text("0"))
    last_used_at: Mapped[dt.datetime] = mapped_column(TIMESTAMP(timezone=True), nullable=False)


__all__ = [
    "Account",
    "Attachment",
    "BodyPart",
    "Draft",
    "KnownRecipient",
    "Mailbox",
    "Message",
    "Outbox",
    "SavedSearch",
    "Thread",
    "User",
]