"""SQLite-Zugriff: Schema, Verbindung, Hilfsfunktionen.

Die Datenbank wird vom Poller-Dienst geschrieben und vom Web-Dienst gelesen.
WAL-Modus erlaubt gleichzeitiges Lesen/Schreiben ohne Sperrkonflikte.
"""
import sqlite3
from contextlib import contextmanager

from . import config

SCHEMA = """
CREATE TABLE IF NOT EXISTS tickets (
    id                      INTEGER PRIMARY KEY,
    number                  TEXT,
    title                   TEXT,
    state                   TEXT,
    state_id                INTEGER,
    priority                TEXT,
    priority_id             INTEGER,
    owner                   TEXT,
    owner_id                INTEGER,
    "group"                 TEXT,
    customer                TEXT,
    article_count           INTEGER,
    zammad_created_at       TEXT,
    zammad_updated_at       TEXT,
    last_contact_at         TEXT,
    last_contact_agent_at   TEXT,
    last_contact_customer_at TEXT,
    close_at                TEXT,
    last_close_at           TEXT,
    raw_json                TEXT,
    first_seen_at           TEXT,
    last_synced_at          TEXT
);

CREATE TABLE IF NOT EXISTS changes (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    ticket_id     INTEGER NOT NULL,
    ticket_number TEXT,
    ticket_title  TEXT,
    field         TEXT NOT NULL,
    label         TEXT,
    old_value     TEXT,
    new_value     TEXT,
    detail        TEXT,
    detected_at   TEXT NOT NULL,
    seen          INTEGER NOT NULL DEFAULT 0,
    notified      INTEGER NOT NULL DEFAULT 0
);

CREATE INDEX IF NOT EXISTS idx_changes_detected ON changes(detected_at DESC);
CREATE INDEX IF NOT EXISTS idx_changes_ticket   ON changes(ticket_id);
CREATE INDEX IF NOT EXISTS idx_changes_seen     ON changes(seen);

CREATE TABLE IF NOT EXISTS sync_runs (
    id           INTEGER PRIMARY KEY AUTOINCREMENT,
    started_at   TEXT,
    finished_at  TEXT,
    ticket_count INTEGER,
    change_count INTEGER,
    status       TEXT,
    error        TEXT
);
"""


def connect() -> sqlite3.Connection:
    conn = sqlite3.connect(config.DB_PATH, timeout=30)
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA journal_mode=WAL;")
    conn.execute("PRAGMA busy_timeout=10000;")
    conn.execute("PRAGMA foreign_keys=ON;")
    return conn


@contextmanager
def get_conn():
    conn = connect()
    try:
        yield conn
        conn.commit()
    finally:
        conn.close()


def init_db() -> None:
    with get_conn() as conn:
        conn.executescript(SCHEMA)