"""Chat-list helpers with no Qt, shared by the Chats dialog and the
terminal's /chats: turning what GET /desk/chats returns into readable rows."""

from __future__ import annotations

import re
from datetime import datetime, timezone
from typing import Optional

# Context notes clients append to what you typed. They're in the stored last
# message, but they aren't what you said, so they stay out of the preview.
# The preview may be cut off mid-note, so an unclosed one runs to the end.
_CONTEXT_NOTES = re.compile(r"\s*\[(?:Bolt Console:|on screen right now:)[^\]]*(?:\]|$)", re.IGNORECASE)


def clean_preview(text: str, limit: int = 110) -> str:
    text = " ".join(_CONTEXT_NOTES.sub("", str(text or "")).split())
    return text if len(text) <= limit else text[: limit - 1].rstrip() + "…"


def relative_time(iso: str, now: Optional[datetime] = None) -> str:
    """'just now', '12 min ago', '3 h ago', 'yesterday', '4 days ago', or a
    date. Unparseable input comes back as it was."""
    try:
        then = datetime.fromisoformat(str(iso).replace("Z", "+00:00"))
    except (TypeError, ValueError):
        return str(iso or "")
    if then.tzinfo is None:
        then = then.replace(tzinfo=timezone.utc)
    now = now or datetime.now(timezone.utc)
    seconds = (now - then).total_seconds()
    if seconds < 60:
        return "just now"
    if seconds < 3600:
        return f"{int(seconds // 60)} min ago"
    if seconds < 86400:
        return f"{int(seconds // 3600)} h ago"
    days = int(seconds // 86400)
    if days == 1:
        return "yesterday"
    if days < 7:
        return f"{days} days ago"
    return then.astimezone().strftime("%d %b %Y").lstrip("0")


def local_time(iso: str) -> str:
    try:
        then = datetime.fromisoformat(str(iso).replace("Z", "+00:00"))
        if then.tzinfo is None:
            then = then.replace(tzinfo=timezone.utc)
        return then.astimezone().strftime("%A %d %B %Y, %H:%M")
    except (TypeError, ValueError):
        return str(iso or "")