"""Interactive (``setup``) + non-interactive (``init``) opt-in flow.

Both end up doing the same thing — write a fresh sync.json + token to
``<pack>/.cloud-sync/``. Difference is just how the URL + token get
collected:

  setup      Qt login dialog for token; URL prompted at stdin if not
             supplied via ``--url`` flag. Falls back to all-stdin when
             headless / Qt missing.
  init       Both URL + token come from flags. No prompting. Suitable
             for scripted CI runs or external launcher hooks (frazclient,
             discord-bot ``/cloud register`` integration).

This is the only path that creates sync.json; pull/push never auto-mint.
That makes opt-in explicit — a player intentionally enables sync rather
than being silently signed up the first time they launch an instance.
"""

from __future__ import annotations

import sys
from pathlib import Path

from . import config as cfgmod
from .cli import Args


def run(
    args: Args,
    url: str | None,
    token: str | None,
    interactive: bool,
) -> int:
    """Drive the opt-in flow. Returns CLI exit code (0/1/2)."""
    pack = args.pack_folder
    cfg_path = cfgmod.config_path(pack)

    if cfgmod.exists(pack):
        existing = cfgmod.read(pack)
        if existing is not None:
            print(
                f"instance-sync: this instance is already sync-enabled\n"
                f"  sync.json:   {cfg_path}\n"
                f"  url:         {existing.url}\n"
                f"  instance_id: {existing.instance_id}\n"
                f"  created_at:  {existing.created_at}\n"
                "Run with `disable` first if you want to re-enroll.",
                file=sys.stderr,
            )
            return 2

    if cfgmod.disabled_path(pack).exists():
        print(
            f"instance-sync: a disabled sync.json is present at "
            f"{cfgmod.disabled_path(pack)}\n"
            "Use `instance-sync enable` to resume the SAME instance_id "
            "(snapshots continue), or `instance-sync disable` again to "
            "discard it before a fresh setup.",
            file=sys.stderr,
        )
        return 2

    if url is None:
        if not interactive:
            print(
                "instance-sync: --url is required for `init`",
                file=sys.stderr,
            )
            return 2
        url = _prompt_url()
        if not url:
            return 1

    if token is None:
        token = _prompt_token(headless=args.headless or not interactive)
        if token is None:
            print("instance-sync: setup cancelled (no token)", file=sys.stderr)
            return 1

    if ":" not in token:
        print(
            "instance-sync: token must be discord_id:password",
            file=sys.stderr,
        )
        return 2
    head, _, tail = token.partition(":")
    if not head.strip().isdigit() or not tail.strip():
        print(
            "instance-sync: token malformed (discord_id must be numeric, "
            "password must be non-empty)",
            file=sys.stderr,
        )
        return 2

    cfg = cfgmod.mint(url=url.strip())
    cfgmod.write(pack, cfg)

    args.token_file.parent.mkdir(parents=True, exist_ok=True)
    args.token_file.write_text(token.strip() + "\n", encoding="utf-8")
    args.token_file.chmod(0o600)

    print(
        f"instance-sync: enabled\n"
        f"  sync.json:   {cfg_path}\n"
        f"  token:       {args.token_file}\n"
        f"  url:         {cfg.url}\n"
        f"  instance_id: {cfg.instance_id}"
    )
    return 0


def _prompt_url() -> str:
    """stdin prompt for the network endpoint."""
    try:
        v = input("Timemachine Network URL (e.g. https://cloud.tm.center): ").strip()
        return v
    except (EOFError, KeyboardInterrupt):
        return ""


def _prompt_token(headless: bool) -> str | None:
    """Returns the discord_id:password token string, or None if user cancelled."""
    if not headless:
        try:
            from .ui_qt import prompt_login_qt
        except ImportError:
            pass
        else:
            return prompt_login_qt()
    # Headless fallback.
    try:
        return input("Paste token (discord_id:password): ").strip()
    except (EOFError, KeyboardInterrupt):
        return None