"""
Workbook resolution helpers for the Wuling overseas dealer expansion skill.

Rules:
- An explicit --excel path always wins.
- Otherwise, prefer an existing project workbook in the current directory or parents.
- Preview mode never creates a workbook.
- Write mode may copy the blank skill template into the project directory.
- Never write directly to the skill template.
"""
from __future__ import annotations

import shutil
from pathlib import Path
from typing import Any, Dict, Optional

CANONICAL_WORKBOOK_NAME = "\u6469\u6d1b\u54e5\u5ba2\u6237\u5efa\u8054\u8868-\u6309\u6e20\u9053\u5206\u7c7b.xlsx"
TEMPLATE_RELATIVE_PATH = Path("assets") / "blank_customer_outreach_workbook.xlsx"
WORKBOOK_NAME_MARKERS = (
    "\u6469\u6d1b\u54e5\u5ba2\u6237\u5efa\u8054\u8868-\u6309\u6e20\u9053\u5206\u7c7b",
    "\u5ba2\u6237\u5efa\u8054\u8868",
)
EXCLUDE_NAME_MARKERS = (
    "~$",
    "_backup_",
    "backup_before",
    "_with_",
    "sent_",
    "preview",
    "candidate",
    "filtered",
)


def skill_root() -> Path:
    return Path(__file__).resolve().parents[2]


def template_workbook_path(root: Optional[Path] = None) -> Path:
    return (root or skill_root()) / TEMPLATE_RELATIVE_PATH


def _resolve_user_path(excel_path: str) -> Path:
    path = Path(excel_path).expanduser()
    if not path.is_absolute():
        path = Path.cwd() / path
    return path.resolve()


def _excluded(path: Path) -> bool:
    name = path.name
    lowered = name.casefold()
    return name.startswith("~$") or any(marker.casefold() in lowered for marker in EXCLUDE_NAME_MARKERS)


def _looks_like_workbook(path: Path) -> bool:
    if path.suffix.casefold() != ".xlsx" or _excluded(path):
        return False
    return any(marker in path.name for marker in WORKBOOK_NAME_MARKERS)


def find_project_workbook(start_dir: Optional[Path] = None) -> Optional[Path]:
    """Find the newest likely outreach workbook in start_dir or its parents."""
    current = (start_dir or Path.cwd()).resolve()
    search_dirs = [current, *current.parents]
    for directory in search_dirs:
        if not directory.exists() or not directory.is_dir():
            continue
        candidates = [path for path in directory.glob("*.xlsx") if _looks_like_workbook(path)]
        if not candidates:
            continue
        exact = [path for path in candidates if path.name == CANONICAL_WORKBOOK_NAME]
        return sorted(exact or candidates, key=lambda path: path.stat().st_mtime, reverse=True)[0]
    return None


def _copy_template_to(target: Path, root: Optional[Path] = None) -> Path:
    template = template_workbook_path(root)
    if not template.exists():
        raise FileNotFoundError(f"Blank workbook template not found: {template}")
    if template.resolve() == target.resolve():
        raise ValueError("Refusing to write directly to the skill blank workbook template.")
    target.parent.mkdir(parents=True, exist_ok=True)
    shutil.copy2(template, target)
    return target


def resolve_workbook_path(
    excel_path: str = "",
    *,
    start_dir: Optional[Path] = None,
    create_from_template: bool = False,
    template_root: Optional[Path] = None,
) -> Dict[str, Any]:
    """
    Resolve the workbook path according to skill rules.

    Returns a dict with: path, source, created.
    source is one of explicit, explicit_template_copy, project, template_copy, missing.
    """
    if excel_path:
        path = _resolve_user_path(excel_path)
        if path.resolve() == template_workbook_path(template_root).resolve():
            raise ValueError("Do not write to the skill blank workbook template. Copy it to the project first.")
        if create_from_template and not path.exists():
            _copy_template_to(path, template_root)
            return {"path": path, "source": "explicit_template_copy", "created": True}
        return {"path": path, "source": "explicit", "created": False}

    project = find_project_workbook(start_dir)
    if project:
        return {"path": project, "source": "project", "created": False}

    if create_from_template:
        target_dir = (start_dir or Path.cwd()).resolve()
        target = target_dir / CANONICAL_WORKBOOK_NAME
        _copy_template_to(target, template_root)
        return {"path": target, "source": "template_copy", "created": True}

    return {"path": None, "source": "missing", "created": False}