"""
Kin — двусторонний sync с Obsidian vault.

Export: decisions → .md-файлы с YAML frontmatter
Import: чекбоксы в .md-файлах → статус задач
"""

import re
import sqlite3
from pathlib import Path
from typing import Optional

from core import models


def _slug(title: str) -> str:
    """Генерирует slug из заголовка для имени файла."""
    s = title.lower()
    s = re.sub(r"[^a-zа-я0-9\s-]", "", s)
    s = re.sub(r"\s+", "-", s.strip())
    return s[:50]


def _decision_to_md(decision: dict) -> str:
    """Форматирует decision как .md файл с YAML frontmatter."""
    tags = decision.get("tags") or []
    if isinstance(tags, str):
        try:
            import json
            tags = json.loads(tags)
        except Exception:
            tags = []

    tags_str = "[" + ", ".join(str(t) for t in tags) + "]"
    created_at = (decision.get("created_at") or "")[:10]  # только дата

    frontmatter = (
        "---\n"
        f"kin_decision_id: {decision['id']}\n"
        f"project: {decision['project_id']}\n"
        f"type: {decision['type']}\n"
        f"category: {decision.get('category') or ''}\n"
        f"tags: {tags_str}\n"
        f"created_at: {created_at}\n"
        "---\n"
    )

    body = f"\n# {decision['title']}\n\n{decision['description']}\n"
    return frontmatter + body


def _parse_frontmatter(text: str) -> dict:
    """Парсит YAML frontmatter из .md файла (упрощённый парсер через re)."""
    result = {}
    match = re.match(r"^---\n(.*?)\n---", text, re.DOTALL)
    if not match:
        return result
    for line in match.group(1).splitlines():
        if ":" in line:
            key, _, val = line.partition(":")
            result[key.strip()] = val.strip()
    return result


def export_decisions_to_md(
    project_id: str,
    decisions: list[dict],
    vault_path: Path,
) -> list[Path]:
    """Экспортирует decisions в .md-файлы Obsidian. Возвращает список созданных файлов."""
    out_dir = vault_path / project_id / "decisions"
    out_dir.mkdir(parents=True, exist_ok=True)

    created: list[Path] = []
    for d in decisions:
        slug = _slug(d["title"])
        fname = f"{d['id']}-{slug}.md"
        fpath = out_dir / fname
        fpath.write_text(_decision_to_md(d), encoding="utf-8")
        created.append(fpath)

    return created


def parse_task_checkboxes(
    vault_path: Path,
    project_id: str,
) -> list[dict]:
    """Парсит *.md-файлы в vault/{project_id}/tasks/ и {project_id}/ на чекбоксы с task ID.

    Returns: [{"task_id": "KIN-013", "done": True, "title": "..."}]
    """
    pattern = re.compile(r"^[-*]\s+\[([xX ])\]\s+([A-Z][A-Z0-9]*-(?:[A-Z][A-Z0-9]*-)?\d+)\s+(.+)$")
    results: list[dict] = []

    search_dirs = [
        vault_path / project_id / "tasks",
        vault_path / project_id,
    ]

    for search_dir in search_dirs:
        if not search_dir.is_dir():
            continue
        for md_file in search_dir.glob("*.md"):
            try:
                text = md_file.read_text(encoding="utf-8")
            except OSError:
                continue
            for line in text.splitlines():
                m = pattern.match(line.strip())
                if m:
                    check_char, task_id, title = m.group(1), m.group(2), m.group(3)
                    results.append({
                        "task_id": task_id,
                        "done": check_char.lower() == "x",
                        "title": title.strip(),
                    })

    return results


def sync_obsidian(conn: sqlite3.Connection, project_id: str) -> dict:
    """Оркестратор: export decisions + import checkboxes.

    Returns:
        {
            "exported_decisions": int,
            "tasks_updated": int,
            "errors": list[str],
            "vault_path": str
        }
    """
    project = models.get_project(conn, project_id)
    if not project:
        raise ValueError(f"Project '{project_id}' not found")

    vault_path_str: Optional[str] = project.get("obsidian_vault_path")
    if not vault_path_str:
        raise ValueError(f"obsidian_vault_path not set for project '{project_id}'")

    vault_path = Path(vault_path_str)
    errors: list[str] = []

    # --- Export decisions ---
    exported_count = 0
    if not vault_path.is_dir():
        errors.append(f"Vault path does not exist or is not a directory: {vault_path_str}")
    else:
        try:
            decisions = models.get_decisions(conn, project_id)
            created_files = export_decisions_to_md(project_id, decisions, vault_path)
            exported_count = len(created_files)
        except Exception as e:
            errors.append(f"Export error: {e}")

    # --- Import checkboxes ---
    tasks_updated = 0
    if vault_path.is_dir():
        try:
            checkboxes = parse_task_checkboxes(vault_path, project_id)
            for item in checkboxes:
                if not item["done"]:
                    continue
                task = models.get_task(conn, item["task_id"])
                if task is None:
                    continue
                if task.get("project_id") != project_id:
                    continue
                if task.get("status") != "done":
                    models.update_task(conn, item["task_id"], status="done")
                    tasks_updated += 1
        except Exception as e:
            errors.append(f"Import error: {e}")

    return {
        "exported_decisions": exported_count,
        "tasks_updated": tasks_updated,
        "errors": errors,
        "vault_path": vault_path_str,
    }