from __future__ import annotations

from pathlib import Path

from fastapi import APIRouter, File, Form, Request, UploadFile
from fastapi.responses import FileResponse, RedirectResponse
from starlette.background import BackgroundTask

from app.core.db.common import CommonSessionLocal
from app.core.http_responses import ui_access_denied, not_found_response
from app.core.security.csrf import get_or_create_csrf_token, validate_csrf
from app.core.security.session_auth import get_current_user
from app.core.templating import templates
from app.modules.core.rbac.deps import get_user_permissions, get_user_roles

from .parsers.registry import BANK_OPTIONS
from .service import can_use, create_job, save_uploads, analyze_job, resolve_owned_job, delete_job

router = APIRouter(prefix="/tools/bank-statement-analyzer", tags=["bank-statement-analyzer-ui"])


def _ctx(request, db, user, **extra):
    data = {
        "request": request,
        "current_user": user,
        "current_user_roles": get_user_roles(db, user.id),
        "current_user_permissions": get_user_permissions(db, user.id),
        "csrf_token": get_or_create_csrf_token(request),
        "title": "Bank Statement Analyzer",
        "bank_options": BANK_OPTIONS,
        "selected_bank": "auto",
        "financial_year": "",
        "classification_enabled": True,
    }
    data.update(extra)
    return data


def _auth(request, db):
    user = get_current_user(request, db=db)
    if not user:
        return None, None, RedirectResponse("/login", status_code=303)
    roles = get_user_roles(db, user.id)
    if not can_use(roles):
        return user, roles, ui_access_denied("Bank Statement Analyzer is available only to Partner, Manager, Staff and Consultant roles.")
    return user, roles, None


@router.get("")
def index(request: Request):
    db = CommonSessionLocal()
    try:
        user, roles, denied = _auth(request, db)
        if denied:
            return denied
        return templates.TemplateResponse(
            "modules/bank_statement_analyzer/templates/bank_statement_analyzer/index.html",
            _ctx(request, db, user, error=""),
        )
    finally:
        db.close()


@router.post("/analyze")
async def analyze(
    request: Request,
    csrf_token: str = Form(...),
    bank_selection: str = Form("auto"),
    financial_year: str = Form(""),
    customer_name: str = Form(""),
    account_number: str = Form(""),
    enable_classification: str | None = Form(None),
    statements: list[UploadFile] = File(...),
):
    db = CommonSessionLocal()
    job_dir: Path | None = None
    selected_bank = bank_selection if bank_selection in dict(BANK_OPTIONS) else "auto"
    classification_enabled = enable_classification == "1"
    try:
        user, roles, denied = _auth(request, db)
        if denied:
            return denied
        validate_csrf(request, csrf_token)
        job_id, input_dir, output_dir = create_job(user, roles)
        job_dir = input_dir.parent
        paths = await save_uploads(statements, input_dir)
        summary = analyze_job(
            user=user,
            roles=roles,
            job_id=job_id,
            paths=paths,
            output_dir=output_dir,
            customer_override=customer_name,
            account_override=account_number,
            bank_selection=selected_bank,
            financial_year=financial_year,
            classification_enabled=classification_enabled,
        )
        return templates.TemplateResponse(
            "modules/bank_statement_analyzer/templates/bank_statement_analyzer/result.html",
            _ctx(request, db, user, summary=summary),
        )
    except Exception as exc:
        user = get_current_user(request, db=db)
        if not user:
            return RedirectResponse("/login", status_code=303)
        return templates.TemplateResponse(
            "modules/bank_statement_analyzer/templates/bank_statement_analyzer/index.html",
            _ctx(
                request,
                db,
                user,
                error=str(exc),
                selected_bank=selected_bank,
                financial_year=financial_year,
                classification_enabled=classification_enabled,
            ),
            status_code=400,
        )
    finally:
        db.close()


@router.get("/{job_id}/download")
def download(job_id: str, request: Request):
    db = CommonSessionLocal()
    try:
        user, roles, denied = _auth(request, db)
        if denied:
            return denied
        try:
            job, meta = resolve_owned_job(user, roles, job_id)
        except FileNotFoundError:
            return not_found_response(request, "Analysis job not found or already cleaned up.")
        output = job / "Output" / meta["output_file"]
        if not output.is_file():
            return not_found_response(request, "Analysis workbook not found.")
        return FileResponse(
            path=output,
            filename="Bank_Statement_Analysis.xlsx",
            media_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
            background=BackgroundTask(delete_job, job),
        )
    finally:
        db.close()


@router.post("/{job_id}/delete")
def delete(job_id: str, request: Request, csrf_token: str = Form(...)):
    db = CommonSessionLocal()
    try:
        user, roles, denied = _auth(request, db)
        if denied:
            return denied
        validate_csrf(request, csrf_token)
        try:
            job, _ = resolve_owned_job(user, roles, job_id)
            delete_job(job)
        except FileNotFoundError:
            pass
        return RedirectResponse("/tools/bank-statement-analyzer", status_code=303)
    finally:
        db.close()