"""Соединение с SQLite и схема хаба. Схема создаётся при первом подключении; версия — в setting.schema_version."""
import json
import sqlite3
from contextlib import contextmanager
from datetime import datetime, timezone
from pathlib import Path

SCHEMA_VERSION = 1

SCHEMA = """
CREATE TABLE IF NOT EXISTS setting (
    key   TEXT PRIMARY KEY,
    value TEXT NOT NULL
);
CREATE TABLE IF NOT EXISTS issue (
    key           TEXT PRIMARY KEY,
    id            TEXT,
    issue_type    TEXT,
    summary       TEXT,
    description   TEXT,
    status        TEXT,
    priority      TEXT,
    assignee      TEXT,
    reporter      TEXT,
    duedate       TEXT,
    planned_start TEXT,
    planned_end   TEXT,
    epic_key      TEXT,
    labels        TEXT NOT NULL DEFAULT '[]',
    sprint        TEXT,
    created       TEXT,
    jira_updated  TEXT,
    fetched_at    TEXT NOT NULL,
    neighbor      INTEGER NOT NULL DEFAULT 0
);
CREATE TABLE IF NOT EXISTS issue_link (
    source_key TEXT NOT NULL,
    target_key TEXT NOT NULL,
    link_type  TEXT NOT NULL,
    PRIMARY KEY (source_key, target_key, link_type)
);
CREATE INDEX IF NOT EXISTS ix_issue_link_target ON issue_link(target_key);
CREATE TABLE IF NOT EXISTS issue_note (
    key         TEXT PRIMARY KEY,
    fact_status TEXT,
    work_kind   TEXT,
    done_text   TEXT,
    rest_text   TEXT,
    owner_note  TEXT,
    updated_at  TEXT,
    updated_by  TEXT
);
CREATE TABLE IF NOT EXISTS batch (
    id               INTEGER PRIMARY KEY AUTOINCREMENT,
    title            TEXT NOT NULL,
    author           TEXT NOT NULL,
    created_at       TEXT NOT NULL,
    cancelled_at     TEXT,
    estimate_seconds INTEGER NOT NULL DEFAULT 0
);
CREATE TABLE IF NOT EXISTS command (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    batch_id      INTEGER NOT NULL REFERENCES batch(id),
    seq           INTEGER NOT NULL,
    type          TEXT NOT NULL,
    params        TEXT NOT NULL,
    status        TEXT NOT NULL DEFAULT 'queued',
    claimed_at    TEXT,
    finished_at   TEXT,
    result        TEXT,
    error         TEXT,
    jira_calls    INTEGER NOT NULL DEFAULT 0,
    rate_limited  INTEGER NOT NULL DEFAULT 0,
    pause_seconds INTEGER,
    depends_on    INTEGER REFERENCES command(id)
);
CREATE INDEX IF NOT EXISTS ix_command_status ON command(status, batch_id, seq);
CREATE TABLE IF NOT EXISTS sync_run (
    id           INTEGER PRIMARY KEY AUTOINCREMENT,
    started_at   TEXT NOT NULL,
    finished_at  TEXT,
    kind         TEXT NOT NULL,
    query        TEXT,
    issues_count INTEGER NOT NULL DEFAULT 0,
    links_count  INTEGER NOT NULL DEFAULT 0,
    jira_calls   INTEGER NOT NULL DEFAULT 0,
    rate_limited INTEGER NOT NULL DEFAULT 0,
    command_id   INTEGER
);
CREATE TABLE IF NOT EXISTS agent_status (
    id                 INTEGER PRIMARY KEY CHECK (id = 1),
    last_seen_at       TEXT,
    agent_version      TEXT,
    settings_version   INTEGER,
    current_command_id INTEGER,
    last_jira_call_at  TEXT
);
"""


def now() -> str:
    """Текущее время UTC в ISO-8601 с секундами — единый формат дат в базе."""
    return datetime.now(timezone.utc).replace(microsecond=0).isoformat()


def connect(path) -> sqlite3.Connection:
    """Открыть базу (создать при отсутствии), применить схему. Соединение в автокоммите; для атомарных
    операций — transaction()."""
    is_memory = str(path) == ":memory:"
    if not is_memory:
        Path(path).parent.mkdir(parents=True, exist_ok=True)
    conn = sqlite3.connect(str(path), timeout=10, isolation_level=None, check_same_thread=False)
    conn.row_factory = sqlite3.Row
    if not is_memory:
        conn.execute("PRAGMA journal_mode = WAL")
    conn.execute("PRAGMA foreign_keys = ON")
    migrate(conn)
    return conn


def migrate(conn: sqlite3.Connection) -> None:
    conn.executescript(SCHEMA)
    row = conn.execute("SELECT value FROM setting WHERE key = 'schema_version'").fetchone()
    if row is None:
        conn.execute("INSERT INTO setting(key, value) VALUES ('schema_version', ?)", (json.dumps(SCHEMA_VERSION),))
    conn.execute("INSERT OR IGNORE INTO agent_status(id) VALUES (1)")


@contextmanager
def transaction(conn: sqlite3.Connection):
    """BEGIN IMMEDIATE … COMMIT; при исключении — ROLLBACK. Нужна там, где читаем и пишем вместе (claim, отчёт)."""
    conn.execute("BEGIN IMMEDIATE")
    try:
        yield conn
    except BaseException:
        conn.execute("ROLLBACK")
        raise
    else:
        conn.execute("COMMIT")