CREATE EXTENSION IF NOT EXISTS pgcrypto;

CREATE TABLE IF NOT EXISTS files_nodes (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    parent_id UUID REFERENCES files_nodes(id) ON DELETE CASCADE,
    node_type TEXT NOT NULL CHECK (node_type IN ('folder', 'file', 'google_sheet', 'office_document')),
    title TEXT NOT NULL,
    owner_user_id UUID NOT NULL,
    owner_department_id UUID,
    created_by UUID NOT NULL,
    updated_by UUID,
    storage_key TEXT,
    original_filename TEXT,
    mime_type TEXT,
    extension TEXT,
    size_bytes BIGINT NOT NULL DEFAULT 0,
    office_format TEXT,
    external_url TEXT,
    version INTEGER NOT NULL DEFAULT 1,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    deleted_at TIMESTAMPTZ,
    CONSTRAINT files_nodes_file_storage_check CHECK (
        node_type IN ('folder', 'google_sheet') OR storage_key IS NOT NULL
    )
);

CREATE INDEX IF NOT EXISTS files_nodes_parent_idx ON files_nodes(parent_id) WHERE deleted_at IS NULL;
CREATE INDEX IF NOT EXISTS files_nodes_owner_idx ON files_nodes(owner_user_id) WHERE deleted_at IS NULL;
CREATE INDEX IF NOT EXISTS files_nodes_type_idx ON files_nodes(node_type) WHERE deleted_at IS NULL;

CREATE TABLE IF NOT EXISTS files_access (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    node_id UUID NOT NULL REFERENCES files_nodes(id) ON DELETE CASCADE,
    user_id UUID NOT NULL,
    access_level TEXT NOT NULL CHECK (access_level IN ('view', 'edit')),
    granted_by UUID NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE (node_id, user_id)
);

CREATE INDEX IF NOT EXISTS files_access_node_idx ON files_access(node_id);
CREATE INDEX IF NOT EXISTS files_access_user_idx ON files_access(user_id);

CREATE TABLE IF NOT EXISTS files_public_links (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    node_id UUID NOT NULL REFERENCES files_nodes(id) ON DELETE CASCADE,
    token_hash TEXT NOT NULL UNIQUE,
    access_level TEXT NOT NULL DEFAULT 'view' CHECK (access_level = 'view'),
    expires_at TIMESTAMPTZ NOT NULL,
    created_by UUID NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    revoked_at TIMESTAMPTZ
);

CREATE INDEX IF NOT EXISTS files_public_links_node_idx ON files_public_links(node_id);
CREATE INDEX IF NOT EXISTS files_public_links_active_idx ON files_public_links(token_hash, expires_at) WHERE revoked_at IS NULL;

CREATE TABLE IF NOT EXISTS files_audit_events (
    id BIGSERIAL PRIMARY KEY,
    actor_user_id UUID,
    action TEXT NOT NULL,
    entity_type TEXT NOT NULL,
    entity_id UUID,
    meta JSONB NOT NULL DEFAULT '{}'::jsonb,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE INDEX IF NOT EXISTS files_audit_events_actor_idx ON files_audit_events(actor_user_id, created_at DESC);
CREATE INDEX IF NOT EXISTS files_audit_events_entity_idx ON files_audit_events(entity_type, entity_id, created_at DESC);