"""Backup/restore for a single site: ZFS snapshot for files, mariadb-dump for DB.

Two decoupled streams (see docs/06-backup-and-dr.md). Offsite `zfs send` / rsync
are scheduled separately (Phase 5); this module covers the on-host operations the
CLI drives.
"""
from __future__ import annotations

from datetime import datetime
from pathlib import Path

from . import database, naming, zfs
from .config import Config, Site
from .runner import Runner


def db_backup_dir(cfg: Config, site: Site) -> str:
    return f"/{cfg.pool}/platform/db-backups/{site.customer}/{site.site}"


def dump_database(runner: Runner, cfg: Config, site: Site) -> str | None:
    if not site.database:
        return None
    db = naming.database_name(site.customer, site.site)
    ts = datetime.now().strftime("%Y%m%d-%H%M%S")
    out_dir = db_backup_dir(cfg, site)
    dest = f"{out_dir}/{db}-{ts}.sql"
    runner.mkdir(out_dir)
    pw = "<redacted>" if runner.dry_run else database.root_password(cfg)
    sql = runner.run(
        ["docker", "exec", cfg.mariadb_container, "mariadb-dump",
         "--single-transaction", "--databases", db, "-uroot", f"-p{pw}"],
        capture=True, secret=True,
    )
    if not runner.dry_run:
        runner.write_file(dest, sql)
    else:
        runner._echo(f"DRY write {dest}")
    return dest


def backup_site(runner: Runner, cfg: Config, site: Site) -> dict:
    snap = zfs.snapshot(runner, zfs.web_dataset(cfg, site))
    dump = dump_database(runner, cfg, site)
    return {"snapshot": snap, "dump": dump}


def restore_files(runner: Runner, cfg: Config, site: Site, snapshot: str) -> None:
    ds = zfs.web_dataset(cfg, site)
    name = snapshot if "@" in snapshot else f"{ds}@{snapshot}"
    # -r discards snapshots newer than the target; acceptable for a deliberate restore.
    runner.run(["zfs", "rollback", "-r", name])


def restore_database(runner: Runner, cfg: Config, site: Site, dump_path: str) -> None:
    if not site.database:
        return
    pw = "<redacted>" if runner.dry_run else database.root_password(cfg)
    data = "" if runner.dry_run else Path(dump_path).read_text(encoding="utf-8")
    runner.run(
        ["docker", "exec", "-i", cfg.mariadb_container, "mariadb", "-uroot", f"-p{pw}"],
        input=data, secret=True,
    )