import os
import secrets
from datetime import datetime, timezone

from fastapi import APIRouter, Depends, Form, Request
from fastapi.responses import HTMLResponse, RedirectResponse
import aiosqlite

from app.database import get_db
from app.auth import create_magic_token, verify_magic_token, verify_magic_code, create_session, delete_session
from app.templates_config import templates

router = APIRouter()

ADMIN_EMAIL = os.getenv("ADMIN_EMAIL", "")
SESSION_COOKIE = "session"
SESSION_TTL_DAYS = 30


@router.get("/login", response_class=HTMLResponse)
async def login_page(request: Request):
    if request.cookies.get(SESSION_COOKIE):
        return RedirectResponse("/", status_code=302)
    return templates.TemplateResponse("auth/login.html", {"request": request})


@router.post("/login", response_class=HTMLResponse)
async def login_submit(
    request: Request,
    email: str = Form(...),
    db: aiosqlite.Connection = Depends(get_db),
):
    email = email.strip().lower()

    # Check email is admin, already registered, or has a pending invitation
    if email != ADMIN_EMAIL:
        async with db.execute("SELECT id FROM users WHERE email = ?", (email,)) as cursor:
            existing_user = await cursor.fetchone()
        if existing_user is None:
            async with db.execute(
                "SELECT id FROM invitations WHERE email = ?", (email,)
            ) as cursor:
                invitation = await cursor.fetchone()
            if invitation is None:
                return templates.TemplateResponse(
                    "auth/login.html",
                    {"request": request, "error": "This email address has not been invited."},
                )

    await create_magic_token(email, db)

    return templates.TemplateResponse("auth/check_email.html", {"request": request, "email": email})


@router.post("/auth/verify-code", response_class=HTMLResponse)
async def verify_code(
    request: Request,
    email: str = Form(...),
    code: str = Form(...),
    db: aiosqlite.Connection = Depends(get_db),
):
    code = code.strip()
    verified_email = await verify_magic_code(email, code, db)

    if verified_email is None:
        return templates.TemplateResponse(
            "auth/check_email.html",
            {"request": request, "email": email, "error": "Invalid or expired code. Try again."},
            status_code=400,
        )

    async with db.execute("SELECT id, is_onboarded FROM users WHERE email = ?", (verified_email,)) as cursor:
        user = await cursor.fetchone()

    if user is None:
        user_id = secrets.token_urlsafe(16)
        now = datetime.now(timezone.utc).isoformat()
        await db.execute(
            "INSERT INTO users (id, email, created_at) VALUES (?, ?, ?)",
            (user_id, verified_email, now),
        )
        await db.execute("DELETE FROM invitations WHERE email = ?", (verified_email,))
        await db.commit()
        is_onboarded = False
    else:
        user_id = user["id"]
        is_onboarded = bool(user["is_onboarded"])

    session_token = await create_session(user_id, db)

    redirect_to = "/" if is_onboarded else "/onboarding"
    response = RedirectResponse(redirect_to, status_code=302)
    response.set_cookie(
        SESSION_COOKIE,
        session_token,
        max_age=SESSION_TTL_DAYS * 86400,
        httponly=True,
        samesite="lax",
    )
    return response


@router.get("/auth/verify", response_class=HTMLResponse)
async def auth_verify(
    request: Request,
    token: str,
    db: aiosqlite.Connection = Depends(get_db),
):
    email = await verify_magic_token(token, db)

    if email is None:
        return templates.TemplateResponse(
            "auth/login.html",
            {"request": request, "error": "This link is invalid or has expired. Please request a new one."},
        )

    # Get or create user
    async with db.execute("SELECT id, is_onboarded FROM users WHERE email = ?", (email,)) as cursor:
        user = await cursor.fetchone()

    if user is None:
        user_id = secrets.token_urlsafe(16)
        now = datetime.now(timezone.utc).isoformat()
        await db.execute(
            "INSERT INTO users (id, email, created_at) VALUES (?, ?, ?)",
            (user_id, email, now),
        )
        await db.execute("DELETE FROM invitations WHERE email = ?", (email,))
        await db.commit()
        is_onboarded = False
    else:
        user_id = user["id"]
        is_onboarded = bool(user["is_onboarded"])

    session_token = await create_session(user_id, db)

    redirect_to = "/" if is_onboarded else "/onboarding"
    response = RedirectResponse(redirect_to, status_code=302)
    response.set_cookie(
        SESSION_COOKIE,
        session_token,
        max_age=SESSION_TTL_DAYS * 86400,
        httponly=True,
        samesite="lax",
    )
    return response


@router.get("/logout")
async def logout(request: Request, db: aiosqlite.Connection = Depends(get_db)):
    token = request.cookies.get(SESSION_COOKIE)
    if token:
        await delete_session(token, db)
    response = RedirectResponse("/login", status_code=302)
    response.delete_cookie(SESSION_COOKIE)
    return response