#!/usr/bin/env python3
"""standup_bot.py — CLI Daily Standup Bot, Draft implementation.

Reads ./standup.md, formats a dated summary, writes to ./standup-output/,
and optionally emails via SMTP. Stdlib only.
"""

import argparse
import os
import smtplib
import sys
from datetime import date
from email.mime.text import MIMEText
from pathlib import Path

REQUIRED_SECTIONS = ("## Yesterday", "## Today", "## Blockers")
DEFAULT_INPUT = Path("./standup.md")
DEFAULT_OUTPUT_DIR = Path("./standup-output")


def parse_args(argv=None):
    p = argparse.ArgumentParser(description="Daily standup formatter")
    p.add_argument("--input", type=Path, default=DEFAULT_INPUT, help="standup markdown")
    p.add_argument("--out-dir", type=Path, default=DEFAULT_OUTPUT_DIR, help="output directory")
    p.add_argument("--to", default=None, help="recipient email (overrides STANDUP_TO)")
    return p.parse_args(argv)


def read_standup(path: Path) -> str:
    if not path.exists():
        print(f"error: {path} not found", file=sys.stderr)
        sys.exit(2)
    text = path.read_text(encoding="utf-8")
    missing = [s for s in REQUIRED_SECTIONS if s not in text]
    if missing:
        print(f"error: missing sections {missing!r} in {path}", file=sys.stderr)
        sys.exit(2)
    return text


def format_summary(text: str, source_name: str, recipient: str | None = None) -> str:
    today = date.today().isoformat()
    lines = [f"# Standup — {today}", "", f"_Source: {source_name}_", ""]
    if recipient:
        lines.append(f"_Recipient: {recipient}_")
        lines.append("")
    for section in REQUIRED_SECTIONS:
        lines.append(section)
        lines.append("")
        capture = False
        for line in text.splitlines():
            if line.strip() == section:
                capture = True
                continue
            if capture:
                if line.startswith("## ") and line.strip() != section:
                    break
                lines.append(line)
    return "\n".join(lines) + "\n"


def write_output(summary: str, out_dir: Path) -> Path:
    out_dir.mkdir(parents=True, exist_ok=True)
    out_path = out_dir / f"{date.today().isoformat()}.md"
    out_path.write_text(summary, encoding="utf-8")
    return out_path


def maybe_email(summary: str, to_addr: str | None) -> None:
    host = os.environ.get("SMTP_HOST")
    user = os.environ.get("SMTP_USER")
    pwd = os.environ.get("SMTP_PASS")
    if not (host and user and pwd):
        return
    recipient = to_addr or os.environ.get("STANDUP_TO")
    if not recipient:
        return
    msg = MIMEText(summary)
    msg["Subject"] = f"Standup — {date.today().isoformat()}"
    msg["From"] = user
    msg["To"] = recipient
    with smtplib.SMTP(host) as s:
        s.login(user, pwd)
        s.send_message(msg)


def main(argv=None) -> int:
    args = parse_args(argv)
    text = read_standup(args.input)
    summary = format_summary(text, str(args.input), args.to)
    print(summary, end="")
    write_output(summary, args.out_dir)
    maybe_email(summary, args.to)
    return 0


if __name__ == "__main__":
    sys.exit(main())