#!/usr/bin/env python3
"""inbox-send — send text or a file to another project's top-level inbox/.

Universal cross-project inbox messaging tool. A "project" here is a
directory that contains both a `.ai/` marker (signalling it's a
Claude-managed project) and a top-level `inbox/` directory (Craig's
inbox convention). The script lets you drop a text message or copy a
file into a target project's `inbox/`, with a dated filename that
records the source project so the target's next session picks it up
cleanly.

Usage:
    inbox-send --list
    inbox-send <target> --text "your message" [--name custom-slug]
    inbox-send <target> --file <path>          [--name custom-slug]

<target> is the project's basename (or the numeric index from --list).

Discovery roots default to ~/projects/ and ~/code/ (parent dirs whose
children are scanned). Override with INBOX_SEND_ROOTS (colon-separated
paths) or write paths into ~/.claude/inbox-roots.txt, one per line.
A root may be either a parent directory or a specific project root
(e.g. ~/.emacs.d); if the root itself is a project, it's included
directly.
"""

from __future__ import annotations

import argparse
import os
import re
import shutil
import sys
from datetime import datetime
from pathlib import Path

DEFAULT_ROOTS = [Path.home() / "projects", Path.home() / "code"]
MAX_SLUG_LENGTH = 40
TS_FILENAME_FMT = "%Y-%m-%d-%H%M"
TS_DOC_FMT = "%Y-%m-%d %H:%M:%S %z"


def resolve_roots() -> list[Path]:
    """Resolve discovery roots: env var → config file → defaults."""
    env_roots = os.environ.get("INBOX_SEND_ROOTS")
    if env_roots:
        return [Path(p) for p in env_roots.split(":") if p]
    config = Path.home() / ".claude" / "inbox-roots.txt"
    if config.is_file():
        paths: list[Path] = []
        for line in config.read_text().splitlines():
            line = line.strip()
            if line and not line.startswith("#"):
                paths.append(Path(line).expanduser())
        if paths:
            return paths
    return DEFAULT_ROOTS


def _is_project(path: Path) -> bool:
    """A project has a `.ai/` marker AND a top-level `inbox/` directory."""
    return (path / ".ai").is_dir() and (path / "inbox").is_dir()


def discover_projects(roots: list[Path]) -> list[Path]:
    """Return absolute paths of projects discovered under `roots`.

    A root may be either a parent directory (its children are scanned) or
    a specific project root (included directly if it qualifies).
    """
    projects: list[Path] = []
    for root in roots:
        if not root.is_dir():
            continue
        if _is_project(root):
            projects.append(root)
            continue
        for child in sorted(root.iterdir()):
            if not child.is_dir():
                continue
            if _is_project(child):
                projects.append(child)
    return projects


def find_current_project(start: Path) -> Path | None:
    """Walk up from `start` looking for the nearest dir containing .ai/."""
    cur = start.resolve()
    while cur != cur.parent:
        if (cur / ".ai").is_dir():
            return cur
        cur = cur.parent
    return None


def slugify(text: str, max_length: int = MAX_SLUG_LENGTH) -> str:
    """Turn freeform text into a filename-safe slug."""
    text = text.lower()
    text = re.sub(r"[^a-z0-9\s]+", " ", text)
    text = re.sub(r"\s+", " ", text).strip()
    if not text:
        return ""
    if len(text) <= max_length:
        return text.replace(" ", "-")
    # Truncate, then walk back to the last whitespace to keep a word boundary.
    truncated = text[:max_length]
    last_space = truncated.rfind(" ")
    if last_space > 0:
        truncated = truncated[:last_space]
    return truncated.strip().replace(" ", "-")


def slugify_filename(stem: str, max_length: int = MAX_SLUG_LENGTH) -> str:
    """Slugify a filename stem while preserving its structure.

    Unlike slugify() (for freeform prose), a filename stem is already
    filename-safe and carries meaning in its separators — dots especially.
    The engine.plugin.org plugin-namespace convention encodes the
    engine/plugin boundary in the first dot, so flattening dots to hyphens
    corrupts the name. Keep [A-Za-z0-9._-] and case (e.g. the TOOLARGE-
    prefix convention), turn whitespace runs into single hyphens, drop
    anything else.
    """
    stem = re.sub(r"\s+", "-", stem.strip())
    stem = re.sub(r"[^A-Za-z0-9._-]+", "", stem)
    stem = re.sub(r"-{2,}", "-", stem).strip("-._")
    if not stem:
        return ""
    if len(stem) <= max_length:
        return stem
    truncated = stem[:max_length]
    # Walk back to the last separator so truncation doesn't cut mid-segment.
    last_sep = max(truncated.rfind("-"), truncated.rfind("."), truncated.rfind("_"))
    if last_sep > 0:
        truncated = truncated[:last_sep]
    return truncated.strip("-._")


def find_target(target_name: str, projects: list[Path]) -> Path | None:
    """Resolve `target_name` against the project list (basename or numeric index)."""
    if target_name.isdigit():
        idx = int(target_name) - 1
        if 0 <= idx < len(projects):
            return projects[idx]
        return None
    for p in projects:
        if p.name == target_name:
            return p
    return None


def build_text_org(message: str, source_name: str, timestamp: str) -> str:
    """Wrap a text message in a minimal org-mode skeleton."""
    title = message.strip().splitlines()[0][:60] if message.strip() else "(empty)"
    return (
        f"#+TITLE: {title}\n"
        f"#+SOURCE: from {source_name}\n"
        f"#+DATE: {timestamp}\n\n"
        f"{message.rstrip()}\n"
    )


def send_text(
    target_inbox: Path,
    message: str,
    source_name: str,
    custom_name: str | None,
    now: datetime,
) -> Path:
    """Write a text message into target_inbox as a dated .org file."""
    if not message.strip():
        raise ValueError("--text cannot be empty or whitespace-only")
    slug = custom_name or slugify(message)
    if not slug:
        raise ValueError(f"could not derive a slug from text: {message!r}")
    filename = f"{now.strftime(TS_FILENAME_FMT)}-from-{source_name}-{slug}.org"
    dest = target_inbox / filename
    dest.write_text(build_text_org(message, source_name, now.strftime(TS_DOC_FMT)))
    return dest


def send_file(
    target_inbox: Path,
    src_path: Path,
    source_name: str,
    custom_name: str | None,
    now: datetime,
) -> Path:
    """Copy src_path into target_inbox with a dated, source-tagged name."""
    if not src_path.is_file():
        raise FileNotFoundError(f"source file not found: {src_path}")
    slug = custom_name or slugify_filename(src_path.stem)
    if not slug:
        raise ValueError(f"could not derive a slug from file: {src_path}")
    ext = src_path.suffix
    filename = f"{now.strftime(TS_FILENAME_FMT)}-from-{source_name}-{slug}{ext}"
    dest = target_inbox / filename
    shutil.copy2(src_path, dest)
    return dest


def print_project_list(projects: list[Path], current: Path | None) -> None:
    """Print numbered list of projects, with the current one excluded."""
    others = [p for p in projects if current is None or p.resolve() != current.resolve()]
    if not others:
        print("No projects (.ai/ + inbox/) found under the configured roots.")
        return
    print(f"Available .ai projects ({len(others)}):")
    width = max(len(p.name) for p in others)
    for i, p in enumerate(others, 1):
        print(f"  {i}. {p.name:<{width}}  {p}")


def main() -> int:
    parser = argparse.ArgumentParser(
        description="Send text or a file to another .ai project's inbox/.",
    )
    parser.add_argument(
        "--list", action="store_true",
        help="List available .ai projects and exit.",
    )
    parser.add_argument(
        "target", nargs="?",
        help="Target project basename or numeric index from --list.",
    )
    parser.add_argument(
        "--text",
        help="Text message to drop as an .org file in the target inbox.",
    )
    parser.add_argument(
        "--file", type=Path,
        help="Path to a file to copy into the target inbox.",
    )
    parser.add_argument(
        "--name",
        help="Override the auto-derived filename slug.",
    )
    args = parser.parse_args()

    roots = resolve_roots()
    projects = discover_projects(roots)
    current = find_current_project(Path.cwd())

    if args.list:
        print_project_list(projects, current)
        return 0

    if not args.target:
        parser.error("must provide a target project (or --list)")
    if args.text is None and args.file is None:
        parser.error("must provide --text or --file")
    if args.text is not None and args.file is not None:
        parser.error("--text and --file are mutually exclusive")

    others = [p for p in projects if current is None or p.resolve() != current.resolve()]
    target = find_target(args.target, others)
    if target is None:
        print(f"inbox-send: unknown target {args.target!r}.", file=sys.stderr)
        print("Run `inbox-send --list` to see available projects.", file=sys.stderr)
        return 1

    target_inbox = target / "inbox"
    if not target_inbox.is_dir():
        print(
            f"inbox-send: target {target.name!r} has no top-level inbox/ directory.",
            file=sys.stderr,
        )
        return 1

    source_name = current.name if current else Path.cwd().name
    now = datetime.now().astimezone()

    try:
        if args.text is not None:
            dest = send_text(target_inbox, args.text, source_name, args.name, now)
        else:
            assert args.file is not None
            dest = send_file(target_inbox, args.file, source_name, args.name, now)
    except (ValueError, FileNotFoundError) as exc:
        print(f"inbox-send: {exc}", file=sys.stderr)
        return 1

    print(f"Sent: {dest}")
    return 0


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