from flask import Blueprint, render_template
from app.auth import login_required, get_current_user
from app.db import query, query_one
from app import SYDNEY_TZ
from datetime import datetime, timezone, timedelta

bp = Blueprint("dashboard", __name__)


def calculate_streak(user_id):
    """Calculate current and best consecutive-day check-in streaks."""
    rows = query(
        """SELECT DISTINCT (checked_in_at AT TIME ZONE 'UTC' AT TIME ZONE 'Australia/Sydney')::date AS d
           FROM checkins WHERE user_id = %s ORDER BY d DESC""",
        (user_id,),
    )
    if not rows:
        return {"current": 0, "best": 0}

    days = [r["d"] for r in rows]
    today = datetime.now(SYDNEY_TZ).date()

    # Current streak: must include today or yesterday to count
    current = 0
    expected = today
    if days[0] == today or days[0] == today - timedelta(days=1):
        expected = days[0]
        for d in days:
            if d == expected:
                current += 1
                expected -= timedelta(days=1)
            else:
                break

    # Best streak
    best = 1
    run = 1
    for i in range(1, len(days)):
        if days[i] == days[i - 1] - timedelta(days=1):
            run += 1
            best = max(best, run)
        else:
            run = 1

    best = max(best, current)
    return {"current": current, "best": best}


@bp.route("/")
@login_required
def index():
    user = get_current_user()

    # Get latest check-in
    latest = query_one(
        "SELECT * FROM checkins WHERE user_id = %s ORDER BY checked_in_at DESC LIMIT 1",
        (user["id"],),
    )

    # Get check-in count
    stats = query_one(
        "SELECT COUNT(*) as total_checkins FROM checkins WHERE user_id = %s",
        (user["id"],),
    )

    # Calculate weight change
    first_checkin = query_one(
        "SELECT weight_kg FROM checkins WHERE user_id = %s ORDER BY checked_in_at ASC LIMIT 1",
        (user["id"],),
    )

    weight_change = None
    weight_change_pct = None
    if latest and first_checkin:
        start_w = float(first_checkin["weight_kg"])
        current_w = float(latest["weight_kg"])
        weight_change = round(current_w - start_w, 1)
        if start_w > 0:
            weight_change_pct = round((weight_change / start_w) * 100, 1)

    # Recent check-ins (last 5)
    recent_checkins = query(
        "SELECT * FROM checkins WHERE user_id = %s ORDER BY checked_in_at DESC LIMIT 5",
        (user["id"],),
    )

    # Activity feed (recent check-ins from all users)
    activity = query("""
        SELECT c.*, u.display_name, u.username
        FROM checkins c
        JOIN users u ON c.user_id = u.id
        WHERE u.is_private = FALSE OR u.id = %s
        ORDER BY c.checked_in_at DESC
        LIMIT 10
    """, (user["id"],))

    # Milestones
    milestones = query(
        "SELECT * FROM milestones WHERE user_id = %s ORDER BY achieved_at DESC",
        (user["id"],),
    )

    # Streak
    streak = calculate_streak(user["id"])

    return render_template(
        "dashboard.html",
        user=user,
        latest=latest,
        stats=stats,
        weight_change=weight_change,
        weight_change_pct=weight_change_pct,
        recent_checkins=recent_checkins,
        activity=activity,
        milestones=milestones,
        streak=streak,
    )