"""
Authentication Endpoints for Mitai Jinkendo

Handles login, logout, password reset, and profile authentication.
"""
import os
import secrets
import smtplib
from typing import Optional
from datetime import datetime, timedelta, timezone
from email.mime.text import MIMEText

from fastapi import APIRouter, HTTPException, Header, Depends
from starlette.requests import Request
from slowapi import Limiter
from slowapi.util import get_remote_address

from db import get_db, get_cursor
from auth import hash_pin, verify_pin, make_token, require_auth
from models import LoginRequest, PasswordResetRequest, PasswordResetConfirm, RegisterRequest

router = APIRouter(prefix="/api/auth", tags=["auth"])
limiter = Limiter(key_func=get_remote_address)


@router.post("/login")
@limiter.limit("5/minute")
async def login(req: LoginRequest, request: Request):
    """Login with email + password."""
    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute("SELECT * FROM profiles WHERE email=%s", (req.email.lower().strip(),))
        prof = cur.fetchone()
        if not prof:
            raise HTTPException(401, "Ungültige Zugangsdaten")

        # Verify password
        if not verify_pin(req.password, prof['pin_hash']):
            raise HTTPException(401, "Ungültige Zugangsdaten")

        # Auto-upgrade from SHA256 to bcrypt
        if prof['pin_hash'] and not prof['pin_hash'].startswith('$2'):
            new_hash = hash_pin(req.password)
            cur.execute("UPDATE profiles SET pin_hash=%s WHERE id=%s", (new_hash, prof['id']))

        # Create session
        token = make_token()
        session_days = prof.get('session_days', 30)
        expires = datetime.now() + timedelta(days=session_days)
        cur.execute("INSERT INTO sessions (token, profile_id, expires_at, created) VALUES (%s,%s,%s,CURRENT_TIMESTAMP)",
            (token, prof['id'], expires.isoformat()))

    return {
        "token": token,
        "profile_id": prof['id'],
        "name": prof['name'],
        "role": prof['role'],
        "expires_at": expires.isoformat()
    }


@router.post("/logout")
def logout(x_auth_token: Optional[str]=Header(default=None)):
    """Logout (delete session)."""
    if x_auth_token:
        with get_db() as conn:
            cur = get_cursor(conn)
            cur.execute("DELETE FROM sessions WHERE token=%s", (x_auth_token,))
    return {"ok": True}


@router.get("/me")
def get_me(session: dict=Depends(require_auth)):
    """Get current user info."""
    pid = session['profile_id']
    # Import here to avoid circular dependency
    from routers.profiles import get_profile
    return get_profile(pid, session)


@router.get("/status")
def auth_status():
    """Health check endpoint."""
    return {"status": "ok", "service": "mitai-jinkendo", "version": "v9b"}


@router.put("/pin")
def change_pin(req: dict, session: dict=Depends(require_auth)):
    """Change PIN/password for current user."""
    pid = session['profile_id']
    new_pin = req.get('pin', '')
    if len(new_pin) < 4:
        raise HTTPException(400, "PIN/Passwort muss mind. 4 Zeichen haben")

    new_hash = hash_pin(new_pin)
    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute("UPDATE profiles SET pin_hash=%s WHERE id=%s", (new_hash, pid))

    return {"ok": True}


@router.post("/forgot-password")
@limiter.limit("3/minute")
async def password_reset_request(req: PasswordResetRequest, request: Request):
    """Request password reset email."""
    email = req.email.lower().strip()
    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute("SELECT id, name FROM profiles WHERE email=%s", (email,))
        prof = cur.fetchone()
        if not prof:
            # Don't reveal if email exists
            return {"ok": True, "message": "Falls die E-Mail existiert, wurde ein Reset-Link gesendet."}

        # Generate reset token
        token = secrets.token_urlsafe(32)
        expires = datetime.now() + timedelta(hours=1)

        # Store in sessions table (reuse mechanism)
        cur.execute("INSERT INTO sessions (token, profile_id, expires_at, created) VALUES (%s,%s,%s,CURRENT_TIMESTAMP)",
            (f"reset_{token}", prof['id'], expires.isoformat()))

    # Send email
    try:
        smtp_host = os.getenv("SMTP_HOST")
        smtp_port = int(os.getenv("SMTP_PORT", 587))
        smtp_user = os.getenv("SMTP_USER")
        smtp_pass = os.getenv("SMTP_PASS")
        smtp_from = os.getenv("SMTP_FROM")
        app_url = os.getenv("APP_URL", "https://mitai.jinkendo.de")

        if smtp_host and smtp_user and smtp_pass:
            msg = MIMEText(f"""Hallo {prof['name']},

Du hast einen Passwort-Reset angefordert.

Reset-Link: {app_url}/reset-password?token={token}

Der Link ist 1 Stunde gültig.

Falls du diese Anfrage nicht gestellt hast, ignoriere diese E-Mail.

Dein Mitai Jinkendo Team
""")
            msg['Subject'] = "Passwort zurücksetzen – Mitai Jinkendo"
            msg['From'] = smtp_from
            msg['To'] = email

            with smtplib.SMTP(smtp_host, smtp_port) as server:
                server.starttls()
                server.login(smtp_user, smtp_pass)
                server.send_message(msg)
    except Exception as e:
        print(f"Email error: {e}")

    return {"ok": True, "message": "Falls die E-Mail existiert, wurde ein Reset-Link gesendet."}


@router.post("/reset-password")
def password_reset_confirm(req: PasswordResetConfirm):
    """Confirm password reset with token."""
    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute("SELECT profile_id FROM sessions WHERE token=%s AND expires_at > CURRENT_TIMESTAMP",
            (f"reset_{req.token}",))
        sess = cur.fetchone()
        if not sess:
            raise HTTPException(400, "Ungültiger oder abgelaufener Reset-Link")

        pid = sess['profile_id']
        new_hash = hash_pin(req.new_password)
        cur.execute("UPDATE profiles SET pin_hash=%s WHERE id=%s", (new_hash, pid))
        cur.execute("DELETE FROM sessions WHERE token=%s", (f"reset_{req.token}",))

    return {"ok": True, "message": "Passwort erfolgreich zurückgesetzt"}


# ── Helper: Send Email ────────────────────────────────────────────────────────
def send_email(to_email: str, subject: str, body: str):
    """Send email via SMTP (reusable helper)."""
    try:
        smtp_host = os.getenv("SMTP_HOST")
        smtp_port = int(os.getenv("SMTP_PORT", 587))
        smtp_user = os.getenv("SMTP_USER")
        smtp_pass = os.getenv("SMTP_PASS")
        smtp_from = os.getenv("SMTP_FROM", "noreply@jinkendo.de")

        if not smtp_host or not smtp_user or not smtp_pass:
            print("SMTP not configured, skipping email")
            return False

        msg = MIMEText(body)
        msg['Subject'] = subject
        msg['From'] = smtp_from
        msg['To'] = to_email

        with smtplib.SMTP(smtp_host, smtp_port) as server:
            server.starttls()
            server.login(smtp_user, smtp_pass)
            server.send_message(msg)

        return True
    except Exception as e:
        print(f"Email error: {e}")
        return False


# ── Registration Endpoints ────────────────────────────────────────────────────
@router.post("/register")
@limiter.limit("3/hour")
async def register(req: RegisterRequest, request: Request):
    """Self-registration with email verification."""
    email = req.email.lower().strip()
    name = req.name.strip()
    password = req.password

    # Validation
    if not email or '@' not in email:
        raise HTTPException(400, "Ungültige E-Mail-Adresse")
    if len(password) < 8:
        raise HTTPException(400, "Passwort muss mindestens 8 Zeichen lang sein")
    if not name or len(name) < 2:
        raise HTTPException(400, "Name muss mindestens 2 Zeichen lang sein")

    with get_db() as conn:
        cur = get_cursor(conn)

        # Check if email already exists
        cur.execute("SELECT id FROM profiles WHERE email=%s", (email,))
        if cur.fetchone():
            raise HTTPException(400, "E-Mail-Adresse bereits registriert")

        # Generate verification token
        verification_token = secrets.token_urlsafe(32)
        verification_expires = datetime.now(timezone.utc) + timedelta(hours=24)

        # Create profile (inactive until verified)
        profile_id = str(secrets.token_hex(16))
        pin_hash = hash_pin(password)
        trial_ends = datetime.now(timezone.utc) + timedelta(days=14)  # 14-day trial

        cur.execute("""
            INSERT INTO profiles (
                id, name, email, pin_hash, auth_type, role, tier,
                email_verified, verification_token, verification_expires,
                trial_ends_at, created
            ) VALUES (%s, %s, %s, %s, 'email', 'user', 'free', FALSE, %s, %s, %s, CURRENT_TIMESTAMP)
        """, (profile_id, name, email, pin_hash, verification_token, verification_expires, trial_ends))

    # Send verification email
    app_url = os.getenv("APP_URL", "https://mitai.jinkendo.de")
    verify_url = f"{app_url}/verify?token={verification_token}"

    email_body = f"""Hallo {name},

willkommen bei Mitai Jinkendo!

Bitte bestätige deine E-Mail-Adresse um die Registrierung abzuschließen:

{verify_url}

Der Link ist 24 Stunden gültig.

Dein Mitai Jinkendo Team
"""

    send_email(email, "Willkommen bei Mitai Jinkendo – E-Mail bestätigen", email_body)

    return {
        "ok": True,
        "message": "Registrierung erfolgreich! Bitte prüfe dein E-Mail-Postfach und bestätige deine E-Mail-Adresse."
    }


@router.get("/verify/{token}")
async def verify_email(token: str):
    """Verify email address and activate account."""
    with get_db() as conn:
        cur = get_cursor(conn)

        # Find profile with this verification token
        cur.execute("""
            SELECT id, name, email, email_verified, verification_expires
            FROM profiles
            WHERE verification_token=%s
        """, (token,))

        prof = cur.fetchone()

        if not prof:
            # Token not found - might be already used/verified
            # Check if there's a verified profile (token was deleted after verification)
            raise HTTPException(400, "Verifikations-Link ungültig oder bereits verwendet. Falls du bereits verifiziert bist, melde dich einfach an.")

        if prof['email_verified']:
            raise HTTPException(400, "E-Mail-Adresse bereits bestätigt")

        # Check if token expired
        if prof['verification_expires'] and datetime.now(timezone.utc) > prof['verification_expires']:
            raise HTTPException(400, "Verifikations-Link abgelaufen. Bitte registriere dich erneut.")

        # Mark as verified and clear token
        cur.execute("""
            UPDATE profiles
            SET email_verified=TRUE, verification_token=NULL, verification_expires=NULL
            WHERE id=%s
        """, (prof['id'],))

        # Create session (auto-login after verification)
        session_token = make_token()
        expires = datetime.now(timezone.utc) + timedelta(days=30)
        cur.execute("""
            INSERT INTO sessions (token, profile_id, expires_at, created)
            VALUES (%s, %s, %s, CURRENT_TIMESTAMP)
        """, (session_token, prof['id'], expires))

    return {
        "ok": True,
        "message": "E-Mail-Adresse erfolgreich bestätigt!",
        "token": session_token,
        "profile": {
            "id": prof['id'],
            "name": prof['name'],
            "email": prof['email']
        }
    }


@router.post("/resend-verification")
@limiter.limit("3/hour")
async def resend_verification(req: dict, request: Request):
    """Resend verification email for unverified account."""
    email = req.get('email', '').strip().lower()

    if not email:
        raise HTTPException(400, "E-Mail-Adresse erforderlich")

    with get_db() as conn:
        cur = get_cursor(conn)

        # Find profile by email
        cur.execute("""
            SELECT id, name, email, email_verified, verification_token, verification_expires
            FROM profiles
            WHERE email=%s
        """, (email,))

        prof = cur.fetchone()

        if not prof:
            # Don't leak info about existing emails
            return {"ok": True, "message": "Falls ein Account mit dieser E-Mail existiert, wurde eine Bestätigungs-E-Mail versendet."}

        if prof['email_verified']:
            raise HTTPException(400, "E-Mail-Adresse bereits bestätigt")

        # Generate new verification token
        verification_token = secrets.token_urlsafe(32)
        verification_expires = datetime.now(timezone.utc) + timedelta(hours=24)

        cur.execute("""
            UPDATE profiles
            SET verification_token=%s, verification_expires=%s
            WHERE id=%s
        """, (verification_token, verification_expires, prof['id']))

    # Send verification email
    app_url = os.getenv("APP_URL", "https://mitai.jinkendo.de")
    verify_url = f"{app_url}/verify?token={verification_token}"

    email_body = f"""Hallo {prof['name']},

du hast eine neue Bestätigungs-E-Mail angefordert.

Bitte bestätige deine E-Mail-Adresse, indem du auf folgenden Link klickst:

{verify_url}

Dieser Link ist 24 Stunden gültig.

Falls du diese E-Mail nicht angefordert hast, kannst du sie einfach ignorieren.

Viele Grüße
Dein Mitai Jinkendo Team
"""

    try:
        send_email(
            to=email,
            subject="Neue Bestätigungs-E-Mail - Mitai Jinkendo",
            body=email_body
        )
    except Exception as e:
        print(f"Failed to send verification email: {e}")
        raise HTTPException(500, "E-Mail konnte nicht versendet werden")

    return {"ok": True, "message": "Bestätigungs-E-Mail wurde erneut versendet."}
