"""
===============================================================================
FILE: modules/web_api/routers/files.py
ROLE: Раздача сформированных отчетов и выгрузок с сохранением оригинальных имен.
===============================================================================
"""

import os
import time
import shutil
import urllib.parse
from typing import Optional
from fastapi import APIRouter, HTTPException
from fastapi.responses import FileResponse

router = APIRouter(prefix="/api/v1/files", tags=["Files"])

BASE_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), "../../../"))
WEB_OUTPUT_DIR = os.path.join(BASE_ROOT, "output", "web")
REPORTS_DIR = os.path.join(BASE_ROOT, "output", "reports")
TEMP_REPORTS_DIR = "/tmp/scud_reports"

os.makedirs(WEB_OUTPUT_DIR, exist_ok=True)
os.makedirs(REPORTS_DIR, exist_ok=True)
os.makedirs(TEMP_REPORTS_DIR, exist_ok=True)

SESSION_TTL_HOURS = 24


def purge_old_tool_sessions(tool_dir_path: str):
    if not os.path.exists(tool_dir_path):
        return
    now = time.time()
    cutoff = now - (SESSION_TTL_HOURS * 3600)
    try:
        for entry in os.listdir(tool_dir_path):
            subpath = os.path.join(tool_dir_path, entry)
            if os.path.isdir(subpath):
                if os.path.getmtime(subpath) < cutoff:
                    shutil.rmtree(subpath, ignore_errors=True)
    except Exception:
        pass


@router.get("/download/{tool_name}/{session_uuid}/{filename}")
async def download_file(tool_name: str, session_uuid: str, filename: str):
    safe_tool = os.path.basename(tool_name)
    safe_uuid = os.path.basename(session_uuid)
    safe_filename = os.path.basename(filename)

    file_path = os.path.join(WEB_OUTPUT_DIR, safe_tool, safe_uuid, safe_filename)

    if not os.path.exists(file_path) or not os.path.isfile(file_path):
        raise HTTPException(status_code=404, detail="Файл не найден или срок его действия истек")

    media_type = "application/octet-stream"
    if safe_filename.endswith((".md", ".txt")):
        media_type = "text/markdown; charset=utf-8"
    elif safe_filename.endswith(".xlsx"):
        media_type = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
    elif safe_filename.endswith(".pdf"):
        media_type = "application/pdf"

    encoded_filename = urllib.parse.quote(safe_filename)

    return FileResponse(
        path=file_path,
        media_type=media_type,
        headers={
            "Content-Disposition": f"attachment; filename*=UTF-8''{encoded_filename}"
        }
    )


def _find_report_recursively(target_filename: str) -> Optional[str]:
    """Рекурсивный поиск файла отчета по имени в /tmp и во всех подпапках output/reports/."""
    # 1. Проверяем /tmp/scud_reports
    tmp_path = os.path.join(TEMP_REPORTS_DIR, target_filename)
    if os.path.exists(tmp_path) and os.path.isfile(tmp_path):
        return tmp_path

    # 2. Проверяем прямой путь в output/reports
    direct_path = os.path.join(REPORTS_DIR, target_filename)
    if os.path.exists(direct_path) and os.path.isfile(direct_path):
        return direct_path

    # 3. Рекурсивный поиск по подкаталогам (год/месяц)
    for root, _, files in os.walk(REPORTS_DIR):
        if target_filename in files:
            return os.path.join(root, target_filename)

    return None


@router.get("/download/reports/{filename:path}")
async def download_report_direct(filename: str):
    """
    Прямое скачивание отчетов:
    - Декодирует UTF-8 URL (%20 -> пробел).
    - Ищет файл в output/reports/{YEAR}/{MONTH} и во временном буфере /tmp/scud_reports.
    """
    decoded_name = urllib.parse.unquote(filename).strip()
    safe_filename = os.path.basename(decoded_name)

    target_path = _find_report_recursively(safe_filename)

    if not target_path or not os.path.exists(target_path):
        raise HTTPException(status_code=404, detail="Отчет не найден")

    encoded_filename = urllib.parse.quote(safe_filename)
    return FileResponse(
        path=target_path,
        media_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        headers={"Content-Disposition": f"attachment; filename*=UTF-8''{encoded_filename}"}
    )