from pathlib import Path
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError

from .db import db, utc_now


def _normalize_timezone(value: str) -> str:
    timezone_name = value.strip()
    if not timezone_name:
        return "UTC"
    if timezone_name.startswith("/"):
        marker = "/zoneinfo/"
        if marker in timezone_name:
            timezone_name = timezone_name.split(marker, 1)[1]
        else:
            timezone_name = timezone_name.lstrip("/")
    try:
        ZoneInfo(timezone_name)
    except (ValueError, ZoneInfoNotFoundError):
        return "UTC"
    return timezone_name


def _system_timezone() -> str:
    timezone_file = Path("/etc/timezone")
    if timezone_file.exists():
        value = timezone_file.read_text().strip()
        if value:
            return _normalize_timezone(value)
    return "UTC"


DEFAULT_SETTINGS = {
    "setup_complete": "false",
    "proxmox_node": "",
    "proxmox_storage": "",
    "local_backup_dir": "/var/lib/vz/dump",
    "rclone_path": "/usr/bin/rclone",
    "rclone_remote": "",
    "rclone_remote_path": "pve-cloud-backup",
    "discord_webhook_url": "",
    "allowed_cors_origins": "http://localhost:5173,http://127.0.0.1:5173",
    "default_compression": "zstd",
    "default_backup_mode": "snapshot",
    "default_retention_type": "days",
    "default_retention_value": "30",
    "max_concurrent_backups": "1",
    "timezone": _system_timezone(),
}


def run_migrations() -> None:
    with db() as conn:
        conn.execute(
            """
            CREATE TABLE IF NOT EXISTS schema_migrations (
                version INTEGER PRIMARY KEY,
                applied_at TEXT NOT NULL
            )
            """
        )
        applied = {
            row["version"]
            for row in conn.execute("SELECT version FROM schema_migrations").fetchall()
        }
        if 1 not in applied:
            conn.executescript(
                """
                CREATE TABLE settings (
                    key TEXT PRIMARY KEY,
                    value TEXT NOT NULL,
                    updated_at TEXT NOT NULL
                );

                CREATE TABLE backup_jobs (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    guest_vmid INTEGER NOT NULL,
                    guest_name TEXT NOT NULL,
                    guest_type TEXT NOT NULL CHECK (guest_type IN ('vm','lxc')),
                    node TEXT NOT NULL,
                    enabled INTEGER NOT NULL DEFAULT 1,
                    cron_schedule TEXT NOT NULL,
                    proxmox_storage TEXT NOT NULL,
                    backup_mode TEXT NOT NULL,
                    compression TEXT NOT NULL,
                    retention_type TEXT NOT NULL CHECK (retention_type IN ('days','latest')),
                    retention_value INTEGER NOT NULL,
                    next_run_at TEXT,
                    created_at TEXT NOT NULL,
                    updated_at TEXT NOT NULL
                );

                CREATE TABLE backups (
                    id TEXT PRIMARY KEY,
                    job_id INTEGER,
                    guest_vmid INTEGER NOT NULL,
                    guest_name TEXT NOT NULL,
                    guest_type TEXT NOT NULL,
                    node TEXT NOT NULL,
                    state TEXT NOT NULL,
                    upid TEXT,
                    local_path TEXT,
                    remote_path TEXT,
                    size_bytes INTEGER,
                    error_message TEXT,
                    started_at TEXT NOT NULL,
                    pve_completed_at TEXT,
                    upload_started_at TEXT,
                    completed_at TEXT,
                    deleted_at TEXT,
                    updated_at TEXT NOT NULL,
                    FOREIGN KEY (job_id) REFERENCES backup_jobs(id) ON DELETE SET NULL
                );

                CREATE TABLE notification_logs (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    event_type TEXT NOT NULL,
                    backup_id TEXT,
                    payload TEXT NOT NULL,
                    success INTEGER NOT NULL,
                    error_message TEXT,
                    created_at TEXT NOT NULL,
                    FOREIGN KEY (backup_id) REFERENCES backups(id) ON DELETE SET NULL
                );

                CREATE INDEX idx_backup_jobs_enabled_next_run ON backup_jobs(enabled, next_run_at);
                CREATE INDEX idx_backups_guest_state ON backups(guest_vmid, state);
                CREATE INDEX idx_backups_state ON backups(state);
                """
            )
            now = utc_now()
            conn.executemany(
                "INSERT INTO settings(key, value, updated_at) VALUES (?, ?, ?)",
                [(key, value, now) for key, value in DEFAULT_SETTINGS.items()],
            )
            conn.execute(
                "INSERT INTO schema_migrations(version, applied_at) VALUES (?, ?)",
                (1, now),
            )
        if 2 not in applied:
            now = utc_now()
            conn.execute(
                """
                INSERT INTO settings(key, value, updated_at)
                VALUES ('rclone_remote_path', 'pve-cloud-backup', ?)
                ON CONFLICT(key) DO NOTHING
                """,
                (now,),
            )
            conn.execute(
                "INSERT INTO schema_migrations(version, applied_at) VALUES (?, ?)",
                (2, now),
            )
        if 3 not in applied:
            now = utc_now()
            conn.execute(
                """
                INSERT INTO settings(key, value, updated_at)
                VALUES ('timezone', ?, ?)
                ON CONFLICT(key) DO NOTHING
                """,
                (DEFAULT_SETTINGS["timezone"], now),
            )
            conn.execute(
                "INSERT INTO schema_migrations(version, applied_at) VALUES (?, ?)",
                (3, now),
            )
        if 4 not in applied:
            now = utc_now()
            row = conn.execute("SELECT value FROM settings WHERE key = 'timezone'").fetchone()
            if row:
                normalized_timezone = _normalize_timezone(row["value"])
                if normalized_timezone != row["value"]:
                    conn.execute(
                        "UPDATE settings SET value = ?, updated_at = ? WHERE key = 'timezone'",
                        (normalized_timezone, now),
                    )
            conn.execute(
                "INSERT INTO schema_migrations(version, applied_at) VALUES (?, ?)",
                (4, now),
            )
        if 5 not in applied:
            now = utc_now()
            conn.execute("ALTER TABLE backup_jobs DROP COLUMN proxmox_storage")
            conn.execute(
                "INSERT INTO schema_migrations(version, applied_at) VALUES (?, ?)",
                (5, now),
            )