from __future__ import annotations

from flask import Blueprint, Response, flash, g, redirect, render_template, request, stream_with_context, url_for

from app.auth import role_required
from app.extensions import db
from app.models import Account
from app.services import (
    build_household_csv_template,
    build_household_export_filename,
    delete_household_import_preview,
    get_household_import_conflict_modes,
    list_households,
    load_household_import_preview,
    preview_household_csv,
    stream_household_csv,
    write_audit_log,
    apply_household_import_preview,
)
from app.services.csv_households import CsvImportError

csv_bp = Blueprint("csv", __name__, url_prefix="/csv")


@csv_bp.get("/households/import")
@role_required("admin", "editor")
def import_households_page() -> str:
    preview_token = request.args.get("preview_token", "").strip()
    preview = load_household_import_preview(preview_token) if preview_token else None
    return render_template(
        "csv/import_preview.html",
        preview=preview,
        conflict_modes=get_household_import_conflict_modes(),
    )


@csv_bp.post("/households/import/preview")
@role_required("admin", "editor")
def preview_households_import():
    file_storage = request.files.get("file")
    if file_storage is None or not file_storage.filename:
        flash("请先选择一个 CSV 文件。", "error")
        return redirect(url_for("csv.import_households_page"))

    try:
        preview = preview_household_csv(
            file_name=file_storage.filename,
            file_bytes=file_storage.read(),
        )
    except CsvImportError as exc:
        flash(str(exc), "error")
        return redirect(url_for("csv.import_households_page"))

    flash("CSV 预览已生成，请先检查无效行和冲突行。", "success")
    return redirect(url_for("csv.import_households_page", preview_token=preview["token"]))


@csv_bp.post("/households/import/confirm")
@role_required("admin", "editor")
def confirm_households_import():
    preview_token = request.form.get("preview_token", "").strip()
    conflict_mode = request.form.get("conflict_mode", "").strip()
    preview = load_household_import_preview(preview_token)
    if preview is None:
        flash("导入预览已失效，请重新上传 CSV。", "error")
        return redirect(url_for("csv.import_households_page"))

    current_account = g.current_account if isinstance(getattr(g, "current_account", None), Account) else None
    try:
        summary = apply_household_import_preview(
            preview=preview,
            actor_id=current_account.id if current_account is not None else None,
            conflict_mode=conflict_mode,
        )
    except CsvImportError as exc:
        flash(str(exc), "error")
        return redirect(url_for("csv.import_households_page", preview_token=preview_token))

    write_audit_log(
        action_type="import_households_csv",
        target_type="household",
        actor=current_account,
        target_display_name=str(summary["file_name"]),
        after_data=summary,
        commit=False,
    )
    db.session.commit()
    delete_household_import_preview(preview_token)
    flash(
        f"CSV 导入完成：新增 {summary['rows_created']} 户，更新 {summary['rows_updated']} 户，跳过 {summary['rows_skipped']} 行，无效 {summary['rows_invalid']} 行。",
        "success",
    )
    return redirect(url_for("main.index"))


@csv_bp.get("/households/template")
@role_required("admin", "editor")
def download_household_template() -> Response:
    return Response(
        build_household_csv_template(),
        mimetype="text/csv; charset=utf-8",
        headers={
            "Content-Disposition": f"attachment; filename={build_household_export_filename(scope='template')}",
            "Cache-Control": "no-store",
        },
    )


@csv_bp.get("/households/export")
@role_required("admin", "editor")
def export_households() -> Response:
    scope = request.args.get("scope", "filtered").strip()
    if scope == "all":
        households = list_households(limit=None)
        filename = build_household_export_filename(scope="all")
    else:
        households = list_households(
            search_term=request.args.get("q", "").strip(),
            side=request.args.get("side", "").strip(),
            invite_status=request.args.get("invite_status", "").strip(),
            attendance_status=request.args.get("attendance_status", "").strip(),
            sort_by=request.args.get("sort_by", "updated_at").strip(),
            sort_order=request.args.get("sort_order", "desc").strip(),
            limit=None,
        )
        filename = build_household_export_filename(scope="filtered")

    return Response(
        stream_with_context(stream_household_csv(households)),
        mimetype="text/csv; charset=utf-8",
        headers={
            "Content-Disposition": f"attachment; filename={filename}",
            "Cache-Control": "no-store",
        },
    )