from __future__ import annotations

import sqlite3

from backend.database.migrations.runner import Migration


def upgrade(connection: sqlite3.Connection) -> None:
    statements = (
        """
        CREATE TABLE mentor_preferences (
            user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
            mentor_id TEXT NOT NULL,
            pinned INTEGER NOT NULL DEFAULT 0 CHECK (pinned IN (0, 1)),
            sort_order INTEGER NOT NULL DEFAULT 0,
            updated_at TEXT NOT NULL,
            PRIMARY KEY (user_id, mentor_id)
        )
        """,
        """
        CREATE TABLE llm_requests (
            id TEXT PRIMARY KEY,
            user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
            feature TEXT NOT NULL,
            business_id TEXT NOT NULL,
            prompt_version TEXT NOT NULL,
            status TEXT NOT NULL CHECK (
                status IN ('reserved', 'streaming', 'success', 'failed', 'stopped')
            ),
            started_at TEXT NOT NULL,
            completed_at TEXT,
            duration_ms INTEGER NOT NULL DEFAULT 0,
            error_type TEXT NOT NULL DEFAULT '',
            input_chars INTEGER NOT NULL DEFAULT 0,
            output_chars INTEGER NOT NULL DEFAULT 0
        )
        """,
        "CREATE INDEX llm_requests_user_started_idx ON llm_requests(user_id, started_at)",
        """
        CREATE TABLE llm_attempts (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            request_id TEXT NOT NULL REFERENCES llm_requests(id) ON DELETE CASCADE,
            model_id INTEGER REFERENCES llm_models(id) ON DELETE SET NULL,
            role TEXT NOT NULL CHECK (role IN ('primary', 'fallback')),
            status TEXT NOT NULL CHECK (status IN ('streaming', 'success', 'failed', 'stopped')),
            started_at TEXT NOT NULL,
            completed_at TEXT,
            duration_ms INTEGER NOT NULL DEFAULT 0,
            error_type TEXT NOT NULL DEFAULT '',
            input_chars INTEGER NOT NULL DEFAULT 0,
            output_chars INTEGER NOT NULL DEFAULT 0
        )
        """,
        "CREATE INDEX llm_attempts_request_idx ON llm_attempts(request_id, id)",
        """
        CREATE TABLE mentor_messages (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
            mentor_id TEXT NOT NULL,
            trade_date TEXT NOT NULL,
            role TEXT NOT NULL CHECK (role IN ('user', 'assistant')),
            content TEXT NOT NULL,
            request_id TEXT REFERENCES llm_requests(id) ON DELETE SET NULL,
            status TEXT NOT NULL CHECK (status IN ('complete', 'stopped', 'error')),
            created_at TEXT NOT NULL
        )
        """,
        """
        CREATE INDEX mentor_messages_scope_idx
        ON mentor_messages(user_id, mentor_id, trade_date, id)
        """,
    )
    for statement in statements:
        connection.execute(statement)


def downgrade(connection: sqlite3.Connection) -> None:
    for table in (
        "mentor_messages",
        "llm_attempts",
        "llm_requests",
        "mentor_preferences",
    ):
        connection.execute(f"DROP TABLE {table}")


MIGRATION = Migration(
    version=8,
    name="create_mentor_and_llm_audit",
    signature="mentor-llm:v1:preferences-messages-requests-attempts",
    upgrade=upgrade,
    downgrade=downgrade,
)