"""Machine access to the Files library: API tokens bound to folders, and the Hub folder

Revision ID: 0106_api_tokens
Revises: 0105_job_source_key
Create Date: 2026-10-14

`api_tokens` is a user's token for a machine (a script, the hub): only its SHA-256 is kept, plus the
first characters to recognise it by, and whether its user was told it is about to run out. `api_token_grants` says what it may do in which folder — list,
read, write, delete — so a token reaches nothing it was not given, folder by folder.

A third folder kind, `hub`: the one folder a user exchanges files with their hub machine through.
Like a source folder its name is the client's to render; like an own folder a file may be moved in.
One per user.
"""

import sqlalchemy as sa
from alembic import op

revision: str = "0106_api_tokens"
down_revision: str | None = "0105_job_source_key"
branch_labels: str | None = None
depends_on: str | None = None

_KIND_OLD = (
    "(kind = 'source' AND source_key IS NOT NULL AND name IS NULL)"
    " OR (kind = 'own' AND name IS NOT NULL AND source_key IS NULL)"
)
_KIND_NEW = _KIND_OLD + " OR (kind = 'hub' AND name IS NULL AND source_key IS NULL)"


def upgrade() -> None:
    op.drop_constraint("ck_file_folder_kind", "file_folders", type_="check")
    op.create_check_constraint("ck_file_folder_kind", "file_folders", _KIND_NEW)
    op.create_index(
        "uq_file_folder_hub",
        "file_folders",
        ["user_id"],
        unique=True,
        postgresql_where=sa.text("kind = 'hub'"),
    )
    op.create_table(
        "api_tokens",
        sa.Column("id", sa.Integer(), primary_key=True),
        sa.Column(
            "user_id",
            sa.Integer(),
            sa.ForeignKey("users.id", ondelete="CASCADE"),
            nullable=False,
            index=True,
        ),
        sa.Column("name", sa.String(80), nullable=False),
        sa.Column("prefix", sa.String(16), nullable=False),
        sa.Column("token_hash", sa.String(64), nullable=False, unique=True),
        sa.Column("expires_at", sa.DateTime(timezone=True)),
        sa.Column("last_used_at", sa.DateTime(timezone=True)),
        sa.Column("expiry_warned", sa.Boolean(), nullable=False, server_default=sa.text("false")),
        sa.Column(
            "created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False
        ),
    )
    op.create_table(
        "api_token_grants",
        sa.Column("id", sa.Integer(), primary_key=True),
        sa.Column(
            "token_id",
            sa.Integer(),
            sa.ForeignKey("api_tokens.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column(
            "folder_id",
            sa.Integer(),
            sa.ForeignKey("file_folders.id", ondelete="CASCADE"),
            nullable=False,
            index=True,
        ),
        sa.Column("can_list", sa.Boolean(), nullable=False, server_default=sa.text("false")),
        sa.Column("can_read", sa.Boolean(), nullable=False, server_default=sa.text("false")),
        sa.Column("can_write", sa.Boolean(), nullable=False, server_default=sa.text("false")),
        sa.Column("can_delete", sa.Boolean(), nullable=False, server_default=sa.text("false")),
        sa.UniqueConstraint("token_id", "folder_id", name="uq_api_token_grant"),
        sa.CheckConstraint(
            "can_list OR can_read OR can_write OR can_delete", name="ck_api_token_grant_some"
        ),
    )


def downgrade() -> None:
    op.drop_table("api_token_grants")
    op.drop_table("api_tokens")
    op.drop_index("uq_file_folder_hub", table_name="file_folders")
    # A Hub folder may hold files (their foreign key RESTRICTs a delete): it becomes an own folder,
    # named "Hub <id>" — or "Hub <id> (2)", … when its user already has a folder of that name,
    # which `uq_file_folder_own_name` (per user, case-blind) would refuse.
    conn = op.get_bind()
    hubs = conn.execute(sa.text("SELECT id, user_id FROM file_folders WHERE kind = 'hub'")).all()
    for folder_id, user_id in hubs:
        name, n = f"Hub {folder_id}", 1
        while conn.execute(
            sa.text("SELECT 1 FROM file_folders WHERE user_id = :u AND lower(name) = lower(:n)"),
            {"u": user_id, "n": name},
        ).first():
            n += 1
            name = f"Hub {folder_id} ({n})"
        conn.execute(
            sa.text("UPDATE file_folders SET kind = 'own', name = :n WHERE id = :i"),
            {"n": name, "i": folder_id},
        )
    op.drop_constraint("ck_file_folder_kind", "file_folders", type_="check")
    op.create_check_constraint("ck_file_folder_kind", "file_folders", _KIND_OLD)