"""
Click CLI for cantaloupe export tool.

Commands:
    export      Download machine list Excel from mycantaloupe.com
    configure   Save credentials to ~/.cantaloupe.env

Usage:
    python -m cantaloupe export --output ./exports/
    python -m cantaloupe export --scheduled --output /data/exports/
    python -m cantaloupe configure
"""

import logging
import os
import sys
import time
from pathlib import Path

import click

from cantaloupe.config import load_credentials, prompt_credentials, save_credentials

logger = logging.getLogger(__name__)


# ── helpers ────────────────────────────────────────────────────────────────


def _format_size(size_bytes: int) -> str:
    """Format a byte count into a human-readable string."""
    size: float = size_bytes
    for unit in ("B", "KB", "MB", "GB", "TB"):
        if size < 1024:
            return f"{size:.1f} {unit}"
        size /= 1024
    return f"{size:.1f} PB"


def _count_excel_rows(path: Path) -> int:
    """Count data rows in an Excel file (excluding the header row).

    Uses openpyxl read-only mode for memory efficiency.
    Returns 0 if the row count can't be determined.
    """
    try:
        from openpyxl import load_workbook

        wb = load_workbook(path, read_only=True)
        ws = wb.active
        if ws is None:
            wb.close()
            return 0
        row_count = max(0, (ws.max_row or 0) - 1)  # subtract header
        wb.close()
        return row_count
    except Exception:
        logger.warning("Could not count Excel rows", exc_info=True)
        return 0


def _resolve_output(output: str | None, scheduled: bool) -> Path:
    """Resolve and validate the output path.

    When output is not specified, defaults to the current working directory
    for interactive mode and ~/cantaloupe-exports/ for scheduled/cron mode.
    """
    if output:
        out_path = Path(os.path.expanduser(output))
    elif scheduled:
        out_path = Path.home() / "cantaloupe-exports"
    else:
        out_path = Path.cwd()

    out_path = out_path.resolve()

    # Create parent directory if it's a file path, or the directory itself
    if out_path.suffix:
        out_path.parent.mkdir(parents=True, exist_ok=True)
    else:
        out_path.mkdir(parents=True, exist_ok=True)

    return out_path


# ── CLI group ───────────────────────────────────────────────────────────────


@click.group()
@click.version_option(version="0.1.0", prog_name="cantaloupe")
@click.option(
    "--verbose", "-v",
    is_flag=True,
    help="Enable debug-level logging",
)
@click.pass_context
def cli(ctx: click.Context, verbose: bool) -> None:
    """Cantaloupe Downloader — export machine list from mycantaloupe.com.

    Credentials are loaded from (in priority order):
    \b
      1. CANTALOUPE_EMAIL / CANTALOUPE_PASSWORD environment variables
      2. ~/.cantaloupe.env file
      3. Interactive prompt (unless --scheduled)
    """
    ctx.ensure_object(dict)

    log_level = logging.DEBUG if verbose else logging.INFO
    logging.basicConfig(
        level=log_level,
        format="%(asctime)s [%(levelname)s] %(name)s: %(message)s",
        datefmt="%H:%M:%S",
    )

    # Load from env / file early so all subcommands can access them
    email, password = load_credentials()
    ctx.obj["email"] = email
    ctx.obj["password"] = password


# ── export command ──────────────────────────────────────────────────────────


@cli.command()
@click.option(
    "--output", "-o",
    default=None,
    help="Output directory or file path (default: current dir, or ~/cantaloupe-exports/ when --scheduled)",
)
@click.option(
    "--headless/--visible",
    default=True,
    help="Browser headless mode for Playwright fallback (--visible shows the browser window).",
)
@click.option(
    "--scheduled",
    is_flag=True,
    help="Non-interactive mode for cron usage — skips credential prompts, uses defaults.",
)
@click.option(
    "--email",
    default=None,
    envvar="CANTALOUPE_EMAIL",
    help="Cantaloupe account email (overrides env var and config file).",
)
@click.option(
    "--password",
    default=None,
    envvar="CANTALOUPE_PASSWORD",
    help="Cantaloupe account password (overrides env var and config file).",
)
@click.pass_context
def export(
    ctx: click.Context,
    output: str | None,
    headless: bool,
    scheduled: bool,
    email: str | None,
    password: str | None,
) -> None:
    """Download the machine list Excel export from mycantaloupe.com.

    Authenticates with your Cantaloupe account and downloads the
    VueMachineList ExcelExport file, reporting file size, row count,
    and elapsed time on completion.
    """
    # Resolve credentials (CLI flags > env vars > config file)
    resolved_email = email or ctx.obj.get("email", "")
    resolved_password = password or ctx.obj.get("password", "")

    # If still missing and not in scheduled mode, prompt interactively
    if (not resolved_email or not resolved_password) and not scheduled:
        click.echo("Cantaloupe credentials not found.")
        resolved_email, resolved_password = prompt_credentials()

        if resolved_email and resolved_password:
            # Offer to save for next time
            if click.confirm("Save credentials to ~/.cantaloupe.env?", default=True):
                save_credentials(resolved_email, resolved_password)
                click.echo(f"Credentials saved to ~/.cantaloupe.env")
        else:
            click.echo(
                "No credentials provided. Set CANTALOUPE_EMAIL / CANTALOUPE_PASSWORD\n"
                "environment variables, create ~/.cantaloupe.env, or run\n"
                "  python -m cantaloupe configure",
                err=True,
            )
            raise SystemExit(1)

    if not resolved_email or not resolved_password:
        click.echo(
            "ERROR: Cantaloupe credentials not found.\n"
            "Set CANTALOUPE_EMAIL / CANTALOUPE_PASSWORD env vars, or\n"
            "run interactively once to save to ~/.cantaloupe.env",
            err=True,
        )
        raise SystemExit(1)

    # Push credentials into the environment so src.auth / src.download
    # can pick them up transparently.
    os.environ["CANTALOUPE_EMAIL"] = resolved_email
    os.environ["CANTALOUPE_PASSWORD"] = resolved_password

    # Resolve output path
    out_dir = _resolve_output(output, scheduled)

    if scheduled:
        click.echo("[scheduled] Running in non-interactive mode")

    click.echo(f"Output directory: {out_dir}")
    click.echo("Authenticating with mycantaloupe.com...")

    # Import download module (lazy, avoids import-time side effects)
    from src.download import ExportError, download

    start = time.monotonic()

    try:
        out_path = download(output=str(out_dir))
    except ExportError as e:
        click.echo(f"ERROR: {e}", err=True)
        raise SystemExit(1)
    except KeyboardInterrupt:
        click.echo("\nCancelled by user")
        raise SystemExit(130)

    elapsed = time.monotonic() - start

    # ── report ──────────────────────────────────────────────────────────
    file_size = out_path.stat().st_size
    row_count = _count_excel_rows(out_path)

    click.echo()
    click.echo("Export complete! ✓")
    click.echo(f"  File : {out_path}")
    click.echo(f"  Size : {_format_size(file_size)}")
    if row_count:
        click.echo(f"  Rows : {row_count:,}")
    click.echo(f"  Time : {elapsed:.1f}s")


# ── configure command ───────────────────────────────────────────────────────


@cli.command()
@click.option(
    "--email",
    prompt="Cantaloupe email",
    help="Your mycantaloupe.com account email.",
)
@click.option(
    "--password",
    prompt="Cantaloupe password",
    hide_input=True,
    confirmation_prompt=False,
    help="Your mycantaloupe.com account password.",
)
def configure(email: str, password: str) -> None:
    """Save Cantaloupe credentials to ~/.cantaloupe.env.

    The file is stored with restrictive permissions (owner read/write only)
    so other users on the system cannot read your password.

    To update credentials, run this command again.
    """
    save_credentials(email, password)
    click.echo(f"✓ Credentials saved to ~/.cantaloupe.env")
    click.echo(f"  You can now run: python -m cantaloupe export")


# ── direct invocation ───────────────────────────────────────────────────────

if __name__ == "__main__":
    cli()