feat(backend): read time of my messages from the archive, exact dates and group readers asked from telegram on demand

backend/migrations/versions/d7a3c5e9f2b1_message_reads.py

@@ -0,0 +1,51 @@
+"""message reads
+
+Revision ID: d7a3c5e9f2b1
+Revises: f8c2d6e1a4b7
+Create Date: 2026-10-19 01:00:00.000000
+
+"""
+
+from collections.abc import Sequence
+
+from alembic import op
+
+revision: str = "d7a3c5e9f2b1"
+down_revision: str | None = "f8c2d6e1a4b7"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+_READS = """
+CREATE TABLE message_reads (
+    account_id integer NOT NULL,
+    chat_id bigint NOT NULL,
+    message_id bigint NOT NULL,
+    reader_id bigint NOT NULL,
+    read_at timestamptz NOT NULL,
+    source text NOT NULL,
+    fetched_at timestamptz NOT NULL DEFAULT now(),
+    PRIMARY KEY (account_id, chat_id, message_id, reader_id)
+)
+"""
+
+_FETCHES = """
+CREATE TABLE read_fetches (
+    account_id integer NOT NULL,
+    chat_id bigint NOT NULL,
+    message_id bigint NOT NULL,
+    outcome text NOT NULL,
+    fetched_at timestamptz NOT NULL DEFAULT now(),
+    retry_at timestamptz NOT NULL,
+    PRIMARY KEY (account_id, chat_id, message_id)
+)
+"""
+
+
+def upgrade() -> None:
+    op.execute(_READS)
+    op.execute(_FETCHES)
+
+
+def downgrade() -> None:
+    op.execute("DROP TABLE IF EXISTS read_fetches")
+    op.execute("DROP TABLE IF EXISTS message_reads")