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

bp = Blueprint("leaderboard", __name__)


@bp.route("/leaderboard")
@login_required
def index():
    # Get all users with their weight stats
    users = query("""
        SELECT
            u.id,
            u.display_name,
            u.username,
            u.starting_weight_kg,
            u.goal_weight_kg,
            (SELECT weight_kg FROM checkins WHERE user_id = u.id ORDER BY checked_in_at ASC LIMIT 1) as first_weight,
            (SELECT weight_kg FROM checkins WHERE user_id = u.id ORDER BY checked_in_at DESC LIMIT 1) as current_weight,
            (SELECT COUNT(*) FROM checkins WHERE user_id = u.id) as total_checkins,
            (SELECT checked_in_at FROM checkins WHERE user_id = u.id ORDER BY checked_in_at DESC LIMIT 1) as last_checkin
        FROM users u
        WHERE u.is_private = FALSE
        ORDER BY u.created_at
    """)

    # Calculate rankings
    ranked = []
    for u in users:
        start_w = float(u["starting_weight_kg"] or u["first_weight"] or 0)
        current_w = float(u["current_weight"] or start_w)

        if start_w > 0:
            weight_lost = start_w - current_w
            pct_lost = round((weight_lost / start_w) * 100, 1)
        else:
            weight_lost = 0
            pct_lost = 0

        goal = float(u["goal_weight_kg"]) if u["goal_weight_kg"] else None
        goal_progress = None
        if goal and start_w > goal:
            total_to_lose = start_w - goal
            goal_progress = min(100, round((weight_lost / total_to_lose) * 100, 1)) if total_to_lose > 0 else 0

        ranked.append({
            **u,
            "weight_lost": round(weight_lost, 1),
            "pct_lost": pct_lost,
            "goal_progress": goal_progress,
        })

    # Sort by % lost (descending)
    ranked.sort(key=lambda x: x["pct_lost"], reverse=True)

    # Get earliest and latest check-in dates for date pickers
    date_range = query_one("""
        SELECT
            MIN(c.checked_in_at) AS earliest,
            MAX(c.checked_in_at) AS latest
        FROM checkins c
        JOIN users u ON u.id = c.user_id
        WHERE u.is_private = FALSE
    """)
    earliest = ""
    latest = ""
    if date_range and date_range["earliest"]:
        e = date_range["earliest"]
        l = date_range["latest"]
        if e.tzinfo is None:
            e = e.replace(tzinfo=timezone.utc)
        if l.tzinfo is None:
            l = l.replace(tzinfo=timezone.utc)
        earliest = e.astimezone(SYDNEY_TZ).strftime("%Y-%m-%d")
        latest = l.astimezone(SYDNEY_TZ).strftime("%Y-%m-%d")

    return render_template("leaderboard.html", ranked=ranked, earliest=earliest, latest=latest)