"""Acces SQLite (WAL). Conexiune per-thread, schema idempotenta, heartbeat worker."""

from __future__ import annotations

import sqlite3
from datetime import datetime, timezone
from pathlib import Path

from .config import get_settings

_SCHEMA = Path(__file__).resolve().parent / "schema.sql"


def _connect(db_path: Path) -> sqlite3.Connection:
    db_path.parent.mkdir(parents=True, exist_ok=True)
    conn = sqlite3.connect(db_path, timeout=15.0, isolation_level=None)  # autocommit; tranzactii explicite
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA journal_mode = WAL")
    conn.execute("PRAGMA foreign_keys = ON")
    conn.execute("PRAGMA busy_timeout = 15000")
    return conn


def get_connection() -> sqlite3.Connection:
    """Conexiune noua catre baza configurata. Apelantul o inchide."""
    return _connect(get_settings().db_path)


def init_db() -> None:
    """Creeaza schema daca lipseste + migrari aditive. Idempotent — sigur la fiecare boot."""
    conn = get_connection()
    try:
        conn.executescript(_SCHEMA.read_text(encoding="utf-8"))
        _migrate(conn)
        # Seed fallback nomenclator (doar daca e gol) ca editorul de mapari + fuzzy
        # sa mearga inainte ca worker-ul sa fi luat lista live din RAR.
        from .mapping import seed_nomenclator_if_empty

        seed_nomenclator_if_empty(conn)
    finally:
        conn.close()


def _migrate(conn: sqlite3.Connection) -> None:
    """Migrari aditive pentru DB create inainte de o coloana noua (CREATE IF NOT EXISTS nu altereaza)."""
    # Coloane submissions
    sub_cols = {r["name"] for r in conn.execute("PRAGMA table_info(submissions)").fetchall()}
    if "next_attempt_at" not in sub_cols:
        conn.execute("ALTER TABLE submissions ADD COLUMN next_attempt_at TEXT")
    if "rar_creds_enc" not in sub_cols:
        conn.execute("ALTER TABLE submissions ADD COLUMN rar_creds_enc TEXT")
    if "purge_after" not in sub_cols:
        conn.execute("ALTER TABLE submissions ADD COLUMN purge_after TEXT")
    if "batch_id" not in sub_cols:
        conn.execute("ALTER TABLE submissions ADD COLUMN batch_id INTEGER")
    if "row_index" not in sub_cols:
        conn.execute("ALTER TABLE submissions ADD COLUMN row_index INTEGER")

    # Coloane accounts
    acc_cols = {r["name"] for r in conn.execute("PRAGMA table_info(accounts)").fetchall()}
    if "rar_creds_enc" not in acc_cols:
        conn.execute("ALTER TABLE accounts ADD COLUMN rar_creds_enc TEXT")
    if "active" not in acc_cols:
        # Conturi existente raman active (default 1). Lifecycle consumat de 3.3.
        conn.execute("ALTER TABLE accounts ADD COLUMN active INTEGER NOT NULL DEFAULT 1")
        acc_cols.add("active")
    if "status" not in acc_cols:
        # Stare de ciclu de viata (5.5). Defensiv idempotent (ca is_admin in 3.3b).
        # Default 'active' (trece CHECK pe randurile existente), apoi derivam din `active`:
        # active=0 -> 'pending'. Invariant: active=1 <=> status='active'.
        conn.execute(
            "ALTER TABLE accounts ADD COLUMN status TEXT NOT NULL DEFAULT 'active' "
            "CHECK (status IN ('pending','active','blocked','archived','deleted'))"
        )
        conn.execute(
            "UPDATE accounts SET status='pending' WHERE active=0 AND status='active'"
        )
    # Unicitate CUI (un CUI = un cont); NULL distinct nativ -> conturi fara CUI multiplu.
    conn.execute(
        "CREATE UNIQUE INDEX IF NOT EXISTS ux_accounts_cui ON accounts(cui) WHERE cui IS NOT NULL"
    )

    # Coloane users (DB cu users creata inaintea acestor coloane)
    user_tbl = conn.execute(
        "SELECT name FROM sqlite_master WHERE type='table' AND name='users'"
    ).fetchone()
    if user_tbl:
        user_cols = {r["name"] for r in conn.execute("PRAGMA table_info(users)").fetchall()}
        if "is_admin" not in user_cols:
            conn.execute("ALTER TABLE users ADD COLUMN is_admin INTEGER NOT NULL DEFAULT 0")
        if "email_verified" not in user_cols:
            conn.execute("ALTER TABLE users ADD COLUMN email_verified INTEGER NOT NULL DEFAULT 0")

    # Coloana import_rows.override_json (3.6, Approach B): patch canonic editat in
    # preview, criptat Fernet. Defensiv idempotent (ca is_admin in 3.3b) — DB create
    # inainte de 3.6 nu au coloana.
    irows_tbl = conn.execute(
        "SELECT name FROM sqlite_master WHERE type='table' AND name='import_rows'"
    ).fetchone()
    if irows_tbl:
        irows_cols = {r["name"] for r in conn.execute("PRAGMA table_info(import_rows)").fetchall()}
        if "override_json" not in irows_cols:
            conn.execute("ALTER TABLE import_rows ADD COLUMN override_json TEXT")

    # Index batch_id pe submissions (poate lipsi pe DB veche)
    existing_idx = {r["name"] for r in conn.execute(
        "SELECT name FROM sqlite_master WHERE type='index' AND tbl_name='submissions'"
    ).fetchall()}
    if "idx_submissions_batch" not in existing_idx:
        conn.execute(
            "CREATE INDEX IF NOT EXISTS idx_submissions_batch ON submissions(batch_id) "
            "WHERE batch_id IS NOT NULL"
        )
    if "idx_submissions_account_status" not in existing_idx:
        conn.execute(
            "CREATE INDEX IF NOT EXISTS idx_submissions_account_status "
            "ON submissions(account_id, status)"
        )


def _now_iso() -> str:
    return datetime.now(timezone.utc).isoformat(timespec="seconds")


def write_heartbeat(conn: sqlite3.Connection, *, rar_login_ok: bool = False, detail: str = "") -> None:
    """Worker bate la fiecare iteratie. last_rar_login_ok se actualizeaza doar la login reusit."""
    if rar_login_ok:
        conn.execute(
            "UPDATE worker_heartbeat SET last_beat=?, last_rar_login_ok=?, detail=? WHERE id=1",
            (_now_iso(), _now_iso(), detail),
        )
    else:
        conn.execute(
            "UPDATE worker_heartbeat SET last_beat=?, detail=? WHERE id=1",
            (_now_iso(), detail),
        )


def read_heartbeat(conn: sqlite3.Connection) -> sqlite3.Row | None:
    return conn.execute("SELECT * FROM worker_heartbeat WHERE id=1").fetchone()


def queue_depth(conn: sqlite3.Connection) -> int:
    row = conn.execute("SELECT COUNT(*) AS n FROM submissions WHERE status='queued'").fetchone()
    return int(row["n"]) if row else 0