"""SQLite persistence for per-sender conversation history."""

from __future__ import annotations

import sqlite3
from pathlib import Path

SCHEMA = """
CREATE TABLE IF NOT EXISTS conversations (
    public_key   TEXT PRIMARY KEY,
    contact_name TEXT,
    created_at   TEXT NOT NULL DEFAULT (datetime('now')),
    updated_at   TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS messages (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    public_key  TEXT NOT NULL REFERENCES conversations(public_key),
    role        TEXT NOT NULL CHECK (role IN ('user', 'assistant')),
    content     TEXT NOT NULL,
    created_at  TEXT NOT NULL DEFAULT (datetime('now'))
);

CREATE INDEX IF NOT EXISTS idx_messages_pubkey_id
    ON messages(public_key, id);
"""


def connect(path: str | Path) -> sqlite3.Connection:
    """Open the SQLite DB, ensure the parent dir and schema exist, return the connection."""
    db_path = Path(path)
    db_path.parent.mkdir(parents=True, exist_ok=True)
    conn = sqlite3.connect(db_path, isolation_level=None)  # autocommit
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA journal_mode = WAL;")
    conn.execute("PRAGMA foreign_keys = ON;")
    conn.executescript(SCHEMA)
    return conn


def upsert_conversation(conn: sqlite3.Connection, public_key: str, contact_name: str) -> None:
    conn.execute(
        """
        INSERT INTO conversations (public_key, contact_name)
        VALUES (?, ?)
        ON CONFLICT(public_key) DO UPDATE SET
            contact_name = excluded.contact_name,
            updated_at   = datetime('now')
        """,
        (public_key, contact_name),
    )


def add_message(conn: sqlite3.Connection, public_key: str, role: str, content: str) -> None:
    conn.execute(
        "INSERT INTO messages (public_key, role, content) VALUES (?, ?, ?)",
        (public_key, role, content),
    )


def get_history(conn: sqlite3.Connection, public_key: str) -> list[dict[str, str]]:
    """Return the conversation as OpenAI chat messages, oldest first."""
    rows = conn.execute(
        "SELECT role, content FROM messages WHERE public_key = ? ORDER BY id ASC",
        (public_key,),
    ).fetchall()
    return [{"role": row["role"], "content": row["content"]} for row in rows]