"""
Notifications API — user notification settings and per-user RSS feed.
"""
import base64
import secrets
from xml.etree.ElementTree import Element, SubElement, tostring

import httpx
from fastapi import APIRouter, Depends, HTTPException
from fastapi.responses import Response
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.config import settings as app_settings
from app.core.dependencies import get_current_user
from app.database import get_db
from app.models.notification import NotificationEvent
from app.models.user import User
from app.schemas.schemas import (
    FollowModeTestRequest,
    NotificationEventSchema,
    NotificationSettingsResponse,
    NotificationSettingsUpdate,
    NotificationTestResult,
    NtfyTestRequest,
)

router = APIRouter()

_EVENT_LABELS = {
    "new_document": "New Bill Text",
    "new_amendment": "Amendment Filed",
    "bill_updated": "Bill Updated",
}


def _prefs_to_response(prefs: dict, rss_token: str | None) -> NotificationSettingsResponse:
    return NotificationSettingsResponse(
        ntfy_topic_url=prefs.get("ntfy_topic_url", ""),
        ntfy_auth_method=prefs.get("ntfy_auth_method", "none"),
        ntfy_token=prefs.get("ntfy_token", ""),
        ntfy_username=prefs.get("ntfy_username", ""),
        ntfy_password=prefs.get("ntfy_password", ""),
        ntfy_enabled=prefs.get("ntfy_enabled", False),
        rss_enabled=prefs.get("rss_enabled", False),
        rss_token=rss_token,
        digest_enabled=prefs.get("digest_enabled", False),
        digest_frequency=prefs.get("digest_frequency", "daily"),
        quiet_hours_start=prefs.get("quiet_hours_start"),
        quiet_hours_end=prefs.get("quiet_hours_end"),
    )


@router.get("/settings", response_model=NotificationSettingsResponse)
async def get_notification_settings(
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    user = await db.get(User, current_user.id)
    # Auto-generate RSS token on first visit so the feed URL is always available
    if not user.rss_token:
        user.rss_token = secrets.token_urlsafe(32)
        await db.commit()
        await db.refresh(user)
    return _prefs_to_response(user.notification_prefs or {}, user.rss_token)


@router.put("/settings", response_model=NotificationSettingsResponse)
async def update_notification_settings(
    body: NotificationSettingsUpdate,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    user = await db.get(User, current_user.id)
    prefs = dict(user.notification_prefs or {})

    if body.ntfy_topic_url is not None:
        prefs["ntfy_topic_url"] = body.ntfy_topic_url.strip()
    if body.ntfy_auth_method is not None:
        prefs["ntfy_auth_method"] = body.ntfy_auth_method
    if body.ntfy_token is not None:
        prefs["ntfy_token"] = body.ntfy_token.strip()
    if body.ntfy_username is not None:
        prefs["ntfy_username"] = body.ntfy_username.strip()
    if body.ntfy_password is not None:
        prefs["ntfy_password"] = body.ntfy_password.strip()
    if body.ntfy_enabled is not None:
        prefs["ntfy_enabled"] = body.ntfy_enabled
    if body.rss_enabled is not None:
        prefs["rss_enabled"] = body.rss_enabled
    if body.digest_enabled is not None:
        prefs["digest_enabled"] = body.digest_enabled
    if body.digest_frequency is not None:
        prefs["digest_frequency"] = body.digest_frequency
    if body.quiet_hours_start is not None:
        prefs["quiet_hours_start"] = body.quiet_hours_start
    if body.quiet_hours_end is not None:
        prefs["quiet_hours_end"] = body.quiet_hours_end
    # Allow clearing quiet hours by passing -1
    if body.quiet_hours_start == -1:
        prefs.pop("quiet_hours_start", None)
        prefs.pop("quiet_hours_end", None)

    user.notification_prefs = prefs

    if not user.rss_token:
        user.rss_token = secrets.token_urlsafe(32)

    await db.commit()
    await db.refresh(user)
    return _prefs_to_response(user.notification_prefs or {}, user.rss_token)


@router.post("/settings/rss-reset", response_model=NotificationSettingsResponse)
async def reset_rss_token(
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    """Regenerate the RSS token, invalidating the old feed URL."""
    user = await db.get(User, current_user.id)
    user.rss_token = secrets.token_urlsafe(32)
    await db.commit()
    await db.refresh(user)
    return _prefs_to_response(user.notification_prefs or {}, user.rss_token)


@router.post("/test/ntfy", response_model=NotificationTestResult)
async def test_ntfy(
    body: NtfyTestRequest,
    current_user: User = Depends(get_current_user),
):
    """Send a test push notification to verify ntfy settings."""
    url = body.ntfy_topic_url.strip()
    if not url:
        return NotificationTestResult(status="error", detail="Topic URL is required")

    base_url = (app_settings.PUBLIC_URL or app_settings.LOCAL_URL).rstrip("/")
    headers: dict[str, str] = {
        "Title": "PocketVeto: Test Notification",
        "Priority": "default",
        "Tags": "white_check_mark",
        "Click": f"{base_url}/notifications",
    }
    if body.ntfy_auth_method == "token" and body.ntfy_token.strip():
        headers["Authorization"] = f"Bearer {body.ntfy_token.strip()}"
    elif body.ntfy_auth_method == "basic" and body.ntfy_username.strip():
        creds = base64.b64encode(
            f"{body.ntfy_username.strip()}:{body.ntfy_password}".encode()
        ).decode()
        headers["Authorization"] = f"Basic {creds}"

    try:
        async with httpx.AsyncClient(timeout=10) as client:
            resp = await client.post(
                url,
                content=(
                    "Your PocketVeto notification settings are working correctly. "
                    "Real alerts will link directly to the relevant bill page."
                ).encode("utf-8"),
                headers=headers,
            )
            resp.raise_for_status()
        return NotificationTestResult(status="ok", detail=f"Test notification sent (HTTP {resp.status_code})")
    except httpx.HTTPStatusError as e:
        return NotificationTestResult(status="error", detail=f"HTTP {e.response.status_code}: {e.response.text[:200]}")
    except httpx.RequestError as e:
        return NotificationTestResult(status="error", detail=f"Connection error: {e}")


@router.post("/test/rss", response_model=NotificationTestResult)
async def test_rss(
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    """Verify the user's RSS feed is reachable and return its event count."""
    user = await db.get(User, current_user.id)
    if not user.rss_token:
        return NotificationTestResult(status="error", detail="RSS token not generated — save settings first")

    count_result = await db.execute(
        select(NotificationEvent).where(NotificationEvent.user_id == user.id)
    )
    event_count = len(count_result.scalars().all())

    return NotificationTestResult(
        status="ok",
        detail=f"RSS feed is active with {event_count} event{'s' if event_count != 1 else ''}. Subscribe to the URL shown above.",
        event_count=event_count,
    )


@router.get("/history", response_model=list[NotificationEventSchema])
async def get_notification_history(
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    """Return the 50 most recent notification events for the current user."""
    result = await db.execute(
        select(NotificationEvent)
        .where(NotificationEvent.user_id == current_user.id)
        .order_by(NotificationEvent.created_at.desc())
        .limit(50)
    )
    return result.scalars().all()


@router.post("/test/follow-mode", response_model=NotificationTestResult)
async def test_follow_mode(
    body: FollowModeTestRequest,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    """Simulate dispatcher behaviour for a given follow mode + event type."""
    from sqlalchemy import select as sa_select
    from app.models.follow import Follow

    VALID_MODES = {"pocket_veto", "pocket_boost"}
    VALID_EVENTS = {"new_document", "new_amendment", "bill_updated"}
    if body.mode not in VALID_MODES:
        return NotificationTestResult(status="error", detail=f"mode must be one of {VALID_MODES}")
    if body.event_type not in VALID_EVENTS:
        return NotificationTestResult(status="error", detail=f"event_type must be one of {VALID_EVENTS}")

    result = await db.execute(
        sa_select(Follow).where(
            Follow.user_id == current_user.id,
            Follow.follow_type == "bill",
        ).limit(1)
    )
    follow = result.scalar_one_or_none()
    if not follow:
        return NotificationTestResult(
            status="error",
            detail="No bill follows found — follow at least one bill first",
        )

    # Pocket Veto suppression: brief events are silently dropped
    if body.mode == "pocket_veto" and body.event_type in ("new_document", "new_amendment"):
        return NotificationTestResult(
            status="ok",
            detail=(
                f"✓ Suppressed — Pocket Veto correctly blocked a '{body.event_type}' event. "
                "No ntfy was sent (this is the expected behaviour)."
            ),
        )

    # Everything else would send ntfy — check the user has it configured
    user = await db.get(User, current_user.id)
    prefs = user.notification_prefs or {}
    ntfy_url = prefs.get("ntfy_topic_url", "").strip()
    ntfy_enabled = prefs.get("ntfy_enabled", False)
    if not ntfy_enabled or not ntfy_url:
        return NotificationTestResult(
            status="error",
            detail="ntfy not configured or disabled — enable it in Notification Settings first.",
        )

    bill_url = f"{(app_settings.PUBLIC_URL or app_settings.LOCAL_URL).rstrip('/')}/bills/{follow.follow_value}"
    event_titles = {
        "new_document": "New Bill Text",
        "new_amendment": "Amendment Filed",
        "bill_updated": "Bill Updated",
    }
    mode_label = body.mode.replace("_", " ").title()
    headers: dict[str, str] = {
        "Title": f"[{mode_label} Test] {event_titles[body.event_type]}: {follow.follow_value.upper()}",
        "Priority": "default",
        "Tags": "test_tube",
        "Click": bill_url,
    }
    if body.mode == "pocket_boost":
        headers["Actions"] = (
            f"view, View Bill, {bill_url}; "
            "view, Find Your Rep, https://www.house.gov/representatives/find-your-representative"
        )

    auth_method = prefs.get("ntfy_auth_method", "none")
    ntfy_token = prefs.get("ntfy_token", "").strip()
    ntfy_username = prefs.get("ntfy_username", "").strip()
    ntfy_password = prefs.get("ntfy_password", "").strip()
    if auth_method == "token" and ntfy_token:
        headers["Authorization"] = f"Bearer {ntfy_token}"
    elif auth_method == "basic" and ntfy_username:
        creds = base64.b64encode(f"{ntfy_username}:{ntfy_password}".encode()).decode()
        headers["Authorization"] = f"Basic {creds}"

    message_lines = [
        f"This is a test of {mode_label} mode for bill {follow.follow_value.upper()}.",
        f"Event type: {event_titles[body.event_type]}",
    ]
    if body.mode == "pocket_boost":
        message_lines.append("Tap the action buttons below to view the bill or find your representative.")

    try:
        async with httpx.AsyncClient(timeout=10) as client:
            resp = await client.post(
                ntfy_url,
                content="\n".join(message_lines).encode("utf-8"),
                headers=headers,
            )
            resp.raise_for_status()
        detail = f"✓ ntfy sent (HTTP {resp.status_code})"
        if body.mode == "pocket_boost":
            detail += " — check your phone for 'View Bill' and 'Find Your Rep' action buttons"
        return NotificationTestResult(status="ok", detail=detail)
    except httpx.HTTPStatusError as e:
        return NotificationTestResult(status="error", detail=f"HTTP {e.response.status_code}: {e.response.text[:200]}")
    except httpx.RequestError as e:
        return NotificationTestResult(status="error", detail=f"Connection error: {e}")


@router.get("/feed/{rss_token}.xml", include_in_schema=False)
async def rss_feed(rss_token: str, db: AsyncSession = Depends(get_db)):
    """Public tokenized RSS feed — no auth required."""
    result = await db.execute(select(User).where(User.rss_token == rss_token))
    user = result.scalar_one_or_none()
    if not user:
        raise HTTPException(status_code=404, detail="Feed not found")

    events_result = await db.execute(
        select(NotificationEvent)
        .where(NotificationEvent.user_id == user.id)
        .order_by(NotificationEvent.created_at.desc())
        .limit(50)
    )
    events = events_result.scalars().all()
    return Response(content=_build_rss(events), media_type="application/rss+xml")


def _build_rss(events: list) -> bytes:
    rss = Element("rss", version="2.0")
    channel = SubElement(rss, "channel")
    SubElement(channel, "title").text = "PocketVeto — Bill Alerts"
    SubElement(channel, "description").text = "Updates on your followed bills"
    SubElement(channel, "language").text = "en-us"

    for event in events:
        payload = event.payload or {}
        item = SubElement(channel, "item")
        label = _EVENT_LABELS.get(event.event_type, "Update")
        bill_label = payload.get("bill_label", event.bill_id.upper())
        SubElement(item, "title").text = f"{label}: {bill_label} — {payload.get('bill_title', '')}"
        SubElement(item, "description").text = payload.get("brief_summary", "")
        if payload.get("bill_url"):
            SubElement(item, "link").text = payload["bill_url"]
        SubElement(item, "pubDate").text = event.created_at.strftime("%a, %d %b %Y %H:%M:%S +0000")
        SubElement(item, "guid").text = str(event.id)

    return tostring(rss, encoding="unicode").encode("utf-8")