"""Upload router for handling file uploads."""

import logging
import os
import stat
import tempfile
from dataclasses import dataclass
from pathlib import Path
from typing import BinaryIO

from fastapi import APIRouter, Depends, File, HTTPException, Request, UploadFile
from pydantic import BaseModel, Field

from app.gateway.authz import require_permission
from app.gateway.deps import get_config
from deerflow.config.app_config import AppConfig
from deerflow.config.paths import get_paths
from deerflow.runtime.user_context import get_effective_user_id
from deerflow.sandbox.sandbox_provider import SandboxProvider, get_sandbox_provider
from deerflow.uploads.manager import (
    UPLOAD_STAGING_PREFIX,
    UPLOAD_STAGING_SUFFIX,
    PathTraversalError,
    UnsafeUploadPathError,
    claim_unique_filename,
    delete_file_safe,
    enrich_file_listing,
    ensure_uploads_dir,
    get_uploads_dir,
    list_files_in_dir,
    normalize_filename,
    upload_artifact_url,
    upload_virtual_path,
    validate_upload_destination,
)
from deerflow.utils.file_conversion import CONVERTIBLE_EXTENSIONS, convert_file_to_markdown
from deerflow.utils.file_io import run_file_io

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/threads/{thread_id}/uploads", tags=["uploads"])

UPLOAD_CHUNK_SIZE = 8192
DEFAULT_MAX_FILES = 10
DEFAULT_MAX_FILE_SIZE = 50 * 1024 * 1024
DEFAULT_MAX_TOTAL_SIZE = 100 * 1024 * 1024


@dataclass(slots=True)
class _UploadTempFile:
    file_path: Path
    temp_path: Path
    handle: BinaryIO


class UploadedFileInfo(BaseModel):
    """Uploaded file metadata exposed by upload and list APIs."""

    filename: str
    size: int
    path: str
    virtual_path: str
    artifact_url: str
    extension: str | None = None
    modified: float | None = None
    original_filename: str | None = None
    markdown_file: str | None = None
    markdown_path: str | None = None
    markdown_virtual_path: str | None = None
    markdown_artifact_url: str | None = None


class UploadResponse(BaseModel):
    """Response model for file upload."""

    success: bool
    files: list[UploadedFileInfo]
    message: str
    skipped_files: list[str] = Field(default_factory=list)


class UploadListResponse(BaseModel):
    """Response model for uploaded file listing."""

    files: list[UploadedFileInfo]
    count: int


class UploadLimits(BaseModel):
    """Application-level upload limits exposed to clients."""

    max_files: int
    max_file_size: int
    max_total_size: int


def _make_file_sandbox_writable(file_path: os.PathLike[str] | str) -> None:
    """Ensure uploaded files remain writable when mounted into non-local sandboxes.

    In AIO sandbox mode, the gateway writes the authoritative host-side file
    first, then the sandbox runtime may rewrite the same mounted path. Granting
    world-writable access here prevents permission mismatches between the
    gateway user and the sandbox runtime user.
    """
    file_stat = os.lstat(file_path)
    if stat.S_ISLNK(file_stat.st_mode):
        logger.warning("Skipping sandbox chmod for symlinked upload path: %s", file_path)
        return

    writable_mode = stat.S_IMODE(file_stat.st_mode) | stat.S_IWUSR | stat.S_IWGRP | stat.S_IWOTH | stat.S_IRGRP | stat.S_IROTH
    chmod_kwargs = {"follow_symlinks": False} if os.chmod in os.supports_follow_symlinks else {}
    os.chmod(file_path, writable_mode, **chmod_kwargs)


def _make_file_sandbox_readable(file_path: os.PathLike[str] | str) -> None:
    """Ensure uploaded files are readable by the sandbox process.

    For Docker sandboxes (AIO), the gateway writes files as root with 0o600
    permissions, then bind-mounts the host directory into the container. The
    sandbox process inside the container runs as a non-root user and cannot
    read those files without group/other read bits. This function adds
    ``S_IRGRP | S_IROTH`` so the sandbox can read the uploaded content.
    """
    file_stat = os.lstat(file_path)
    if stat.S_ISLNK(file_stat.st_mode):
        logger.warning("Skipping sandbox chmod for symlinked upload path: %s", file_path)
        return

    readable_mode = stat.S_IMODE(file_stat.st_mode) | stat.S_IRGRP | stat.S_IROTH
    chmod_kwargs = {"follow_symlinks": False} if os.chmod in os.supports_follow_symlinks else {}
    os.chmod(file_path, readable_mode, **chmod_kwargs)


def _uses_thread_data_mounts(sandbox_provider: SandboxProvider) -> bool:
    return bool(getattr(sandbox_provider, "uses_thread_data_mounts", False))


def _get_uploads_config_value(app_config: AppConfig, key: str, default: object) -> object:
    """Read a value from the uploads config, supporting dict and attribute access."""
    uploads_cfg = getattr(app_config, "uploads", None)
    if isinstance(uploads_cfg, dict):
        return uploads_cfg.get(key, default)
    return getattr(uploads_cfg, key, default)


def _get_upload_limit(app_config: AppConfig, key: str, default: int, *, legacy_key: str | None = None) -> int:
    try:
        value = _get_uploads_config_value(app_config, key, None)
        if value is None and legacy_key is not None:
            value = _get_uploads_config_value(app_config, legacy_key, None)
        if value is None:
            value = default
        limit = int(value)
        if limit <= 0:
            raise ValueError
        return limit
    except Exception:
        logger.warning("Invalid uploads.%s value; falling back to %d", key, default)
        return default


def _get_upload_limits(app_config: AppConfig) -> UploadLimits:
    return UploadLimits(
        max_files=_get_upload_limit(app_config, "max_files", DEFAULT_MAX_FILES, legacy_key="max_file_count"),
        max_file_size=_get_upload_limit(app_config, "max_file_size", DEFAULT_MAX_FILE_SIZE, legacy_key="max_single_file_size"),
        max_total_size=_get_upload_limit(app_config, "max_total_size", DEFAULT_MAX_TOTAL_SIZE),
    )


def _cleanup_uploaded_paths(paths: list[os.PathLike[str] | str]) -> None:
    for path in reversed(paths):
        try:
            os.unlink(path)
        except FileNotFoundError:
            pass
        except Exception:
            logger.warning("Failed to clean up upload path after rejected request: %s", path, exc_info=True)


def _prepare_upload_destination(uploads_dir: os.PathLike[str] | str, display_filename: str) -> _UploadTempFile:
    uploads_dir_path = Path(uploads_dir)
    file_path = validate_upload_destination(uploads_dir_path, display_filename)
    temp_fd, temp_path_str = tempfile.mkstemp(prefix=UPLOAD_STAGING_PREFIX, suffix=UPLOAD_STAGING_SUFFIX, dir=uploads_dir_path)
    temp_path = Path(temp_path_str)
    try:
        handle = os.fdopen(temp_fd, "wb")
    except Exception:
        try:
            os.close(temp_fd)
        except OSError:
            pass
        try:
            os.unlink(temp_path)
        except FileNotFoundError:
            pass
        raise
    return _UploadTempFile(file_path=file_path, temp_path=temp_path, handle=handle)


def _write_upload_chunk(upload_temp: _UploadTempFile, chunk: bytes) -> None:
    upload_temp.handle.write(chunk)


def _abort_upload_temp(upload_temp: _UploadTempFile) -> None:
    try:
        upload_temp.handle.close()
    finally:
        try:
            os.unlink(upload_temp.temp_path)
        except FileNotFoundError:
            pass


def _commit_upload_temp(upload_temp: _UploadTempFile) -> None:
    upload_temp.handle.close()
    try:
        os.replace(upload_temp.temp_path, upload_temp.file_path)
    except Exception:
        try:
            os.unlink(upload_temp.temp_path)
        except FileNotFoundError:
            pass
        raise


def _make_uploaded_paths_sandbox_readable(paths: list[os.PathLike[str] | str]) -> None:
    for file_path in paths:
        _make_file_sandbox_readable(file_path)


def _sync_upload_to_sandbox(sandbox, file_path: os.PathLike[str] | str, virtual_path: str) -> None:
    _make_file_sandbox_writable(file_path)
    sandbox.update_file(virtual_path, Path(file_path).read_bytes())


def _list_uploaded_files_for_thread(thread_id: str, user_id: str) -> dict:
    uploads_dir = get_uploads_dir(thread_id, user_id=user_id)
    result = list_files_in_dir(uploads_dir)
    enrich_file_listing(result, thread_id)

    sandbox_uploads = get_paths().sandbox_uploads_dir(thread_id, user_id=user_id)
    for f in result["files"]:
        f["path"] = str(sandbox_uploads / f["filename"])
    return result


def _delete_uploaded_file_for_thread(thread_id: str, filename: str, user_id: str) -> dict:
    uploads_dir = get_uploads_dir(thread_id, user_id=user_id)
    return delete_file_safe(uploads_dir, filename, convertible_extensions=CONVERTIBLE_EXTENSIONS)


async def _write_upload_file_with_limits(
    file: UploadFile,
    *,
    uploads_dir: os.PathLike[str] | str,
    display_filename: str,
    max_single_file_size: int,
    max_total_size: int,
    total_size: int,
) -> tuple[os.PathLike[str] | str, int, int]:
    file_size = 0
    upload_temp: _UploadTempFile | None = None
    try:
        upload_temp = await run_file_io(_prepare_upload_destination, uploads_dir, display_filename)
        while chunk := await file.read(UPLOAD_CHUNK_SIZE):
            file_size += len(chunk)
            total_size += len(chunk)
            if file_size > max_single_file_size:
                raise HTTPException(status_code=413, detail=f"File too large: {display_filename}")
            if total_size > max_total_size:
                raise HTTPException(status_code=413, detail="Total upload size too large")
            await run_file_io(_write_upload_chunk, upload_temp, chunk)

        await run_file_io(_commit_upload_temp, upload_temp)
        file_path = upload_temp.file_path
        upload_temp = None
    except Exception:
        if upload_temp is not None:
            await run_file_io(_abort_upload_temp, upload_temp)
        raise
    return file_path, file_size, total_size


def _auto_convert_documents_enabled(app_config: AppConfig) -> bool:
    """Return whether automatic host-side document conversion is enabled.

    The secure default is disabled unless an operator explicitly opts in via
    uploads.auto_convert_documents in config.yaml.
    """
    try:
        raw = _get_uploads_config_value(app_config, "auto_convert_documents", False)
        if isinstance(raw, str):
            return raw.strip().lower() in {"1", "true", "yes", "on"}
        return bool(raw)
    except Exception:
        return False


@router.post("", response_model=UploadResponse)
@require_permission("threads", "write", owner_check=True, require_existing=False)
async def upload_files(
    thread_id: str,
    request: Request,
    files: list[UploadFile] = File(...),
    config: AppConfig = Depends(get_config),
) -> UploadResponse:
    """Upload multiple files to a thread's uploads directory."""
    if not files:
        raise HTTPException(status_code=400, detail="No files provided")

    limits = _get_upload_limits(config)
    if len(files) > limits.max_files:
        raise HTTPException(status_code=413, detail=f"Too many files: maximum is {limits.max_files}")

    try:
        effective_user_id = get_effective_user_id()
        uploads_dir = await run_file_io(ensure_uploads_dir, thread_id, user_id=effective_user_id)
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    sandbox_uploads = uploads_dir
    uploaded_files = []
    written_paths = []
    sandbox_sync_targets = []
    skipped_files = []
    total_size = 0
    # Track filenames within this request so duplicate form parts do not
    # silently truncate each other. Existing uploads keep the historical
    # overwrite behavior for a single replacement upload.
    seen_filenames: set[str] = set()

    sandbox_provider = get_sandbox_provider()
    sync_to_sandbox = not _uses_thread_data_mounts(sandbox_provider)
    sandbox = None
    if sync_to_sandbox:
        sandbox_id = await sandbox_provider.acquire_async(thread_id, user_id=effective_user_id)
        sandbox = sandbox_provider.get(sandbox_id)
        if sandbox is None:
            raise HTTPException(status_code=500, detail="Failed to acquire sandbox")
    auto_convert_documents = _auto_convert_documents_enabled(config)

    for file in files:
        if not file.filename:
            continue

        try:
            original_filename = normalize_filename(file.filename)
            safe_filename = claim_unique_filename(original_filename, seen_filenames)
        except ValueError:
            logger.warning(f"Skipping file with unsafe filename: {file.filename!r}")
            continue

        try:
            file_path, file_size, total_size = await _write_upload_file_with_limits(
                file,
                uploads_dir=uploads_dir,
                display_filename=safe_filename,
                max_single_file_size=limits.max_file_size,
                max_total_size=limits.max_total_size,
                total_size=total_size,
            )
            written_paths.append(file_path)

            virtual_path = upload_virtual_path(safe_filename)

            if sync_to_sandbox:
                sandbox_sync_targets.append((file_path, virtual_path))

            file_info = {
                "filename": safe_filename,
                "size": file_size,
                "path": str(sandbox_uploads / safe_filename),
                "virtual_path": virtual_path,
                "artifact_url": upload_artifact_url(thread_id, safe_filename),
            }
            if safe_filename != original_filename:
                file_info["original_filename"] = original_filename

            logger.info(f"Saved file: {safe_filename} ({file_size} bytes) to {file_info['path']}")

            file_ext = file_path.suffix.lower()
            if auto_convert_documents and file_ext in CONVERTIBLE_EXTENSIONS:
                # Reserve the companion .md name in this request's seen set
                # before writing so conversion cannot silently truncate another
                # uploaded or derived file (same invariant as form-part dedupe).
                provisional_md_name = Path(safe_filename).with_suffix(".md").name
                unique_md_name = claim_unique_filename(provisional_md_name, seen_filenames)
                md_output = file_path.with_name(unique_md_name)
                md_path = await convert_file_to_markdown(file_path, output_path=md_output)
                if md_path:
                    written_paths.append(md_path)
                    md_virtual_path = upload_virtual_path(md_path.name)

                    if sync_to_sandbox:
                        sandbox_sync_targets.append((md_path, md_virtual_path))

                    file_info["markdown_file"] = md_path.name
                    file_info["markdown_path"] = str(sandbox_uploads / md_path.name)
                    file_info["markdown_virtual_path"] = md_virtual_path
                    file_info["markdown_artifact_url"] = upload_artifact_url(thread_id, md_path.name)
                else:
                    # Conversion failed and wrote nothing, so release the claim;
                    # holding it would rename a later same-stem upload against
                    # a name nothing occupies.
                    seen_filenames.discard(unique_md_name)

            uploaded_files.append(file_info)

        except HTTPException as e:
            await run_file_io(_cleanup_uploaded_paths, written_paths)
            raise e
        except UnsafeUploadPathError as e:
            logger.warning("Skipping upload with unsafe destination %s: %s", file.filename, e)
            skipped_files.append(safe_filename)
            continue
        except Exception as e:
            logger.error(f"Failed to upload {file.filename}: {e}")
            await run_file_io(_cleanup_uploaded_paths, written_paths)
            raise HTTPException(status_code=500, detail=f"Failed to upload {file.filename}: {str(e)}")

    # Uploaded files are created with 0o600 permissions (owner read/write only).
    # In Docker sandbox deployments the gateway writes as root but the sandbox
    # process runs as a non-root user (typically UID 1000).  Without group/other
    # read bits the sandbox cannot access the files — whether the uploads
    # directory is bind-mounted into the container or synced via
    # sandbox.update_file.  Always add group/other read bits so every sandbox
    # configuration can read the uploaded content.
    await run_file_io(_make_uploaded_paths_sandbox_readable, written_paths)

    if sync_to_sandbox:
        for file_path, virtual_path in sandbox_sync_targets:
            await run_file_io(_sync_upload_to_sandbox, sandbox, file_path, virtual_path)

    message = f"Successfully uploaded {len(uploaded_files)} file(s)"
    if skipped_files:
        message += f"; skipped {len(skipped_files)} unsafe file(s)"

    return UploadResponse(
        success=not skipped_files,
        files=uploaded_files,
        message=message,
        skipped_files=skipped_files,
    )


@router.get("/limits", response_model=UploadLimits)
@require_permission("threads", "read", owner_check=True)
async def get_upload_limits(
    thread_id: str,
    request: Request,
    config: AppConfig = Depends(get_config),
) -> UploadLimits:
    """Return upload limits used by the gateway for this thread."""
    return _get_upload_limits(config)


@router.get("/list", response_model=UploadListResponse)
@require_permission("threads", "read", owner_check=True)
async def list_uploaded_files(thread_id: str, request: Request) -> UploadListResponse:
    """List all files in a thread's uploads directory."""
    try:
        result = await run_file_io(_list_uploaded_files_for_thread, thread_id, get_effective_user_id())
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))

    return UploadListResponse(**result)


@router.delete("/{filename}")
@require_permission("threads", "delete", owner_check=True, require_existing=True)
async def delete_uploaded_file(thread_id: str, filename: str, request: Request) -> dict:
    """Delete a file from a thread's uploads directory."""
    try:
        return await run_file_io(_delete_uploaded_file_for_thread, thread_id, filename, get_effective_user_id())
    except FileNotFoundError:
        raise HTTPException(status_code=404, detail=f"File not found: {filename}")
    except PathTraversalError:
        raise HTTPException(status_code=400, detail="Invalid path")
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        logger.error(f"Failed to delete {filename}: {e}")
        raise HTTPException(status_code=500, detail=f"Failed to delete {filename}: {str(e)}")