@page "/Insights"
@using BlazorFrontend.Services
@using LibraryManagement.Shared.Models
@using Microsoft.AspNetCore.Authorization
@attribute [Authorize(Roles = "Librarian")]
@inject LibraryApiClient ApiClient

<PageTitle>User Insights</PageTitle>

<div class="mb-10 animate-in fade-in slide-in-from-top-4 duration-500">
    <h1 class="text-4xl font-extrabold tracking-tight text-mystic-900 border-b border-mystic-100 pb-4 mb-2">User Insights</h1>
    <p class="text-mystic-500 font-medium">Discover top-performing library members and engagement trends.</p>
</div>

@if (_isLoading)
{
    <div class="py-20 flex flex-col items-center justify-center gap-4">
        <div class="animate-spin rounded-full h-12 w-12 border-b-2 border-mystic-900"></div>
        <p class="text-mystic-400 font-medium animate-pulse">Calculating insights...</p>
    </div>
}
else
{
    <!-- Tabs -->
    <div class="flex p-1 bg-mystic-100 rounded-2xl mb-12 max-w-2xl mx-auto shadow-inner">
        <button @onclick='() => _activeTab = "Subscribers"' 
                class='flex-1 py-3 px-6 rounded-xl text-sm font-bold transition-all @(_activeTab == "Subscribers" ? "bg-white text-mystic-900 shadow-sm" : "text-mystic-500 hover:text-mystic-700")'>
            Top Subscribers
        </button>
        <button @onclick='() => _activeTab = "Loyalty"' 
                class='flex-1 py-3 px-6 rounded-xl text-sm font-bold transition-all @(_activeTab == "Loyalty" ? "bg-white text-mystic-900 shadow-sm" : "text-mystic-500 hover:text-mystic-700")'>
            Top Loyalty
        </button>
        <button @onclick='() => _activeTab = "Active"' 
                class='flex-1 py-3 px-6 rounded-xl text-sm font-bold transition-all @(_activeTab == "Active" ? "bg-white text-mystic-900 shadow-sm" : "text-mystic-500 hover:text-mystic-700")'>
            Most Active
        </button>
    </div>

    <!-- Insight Content -->
    <div class="animate-in fade-in zoom-in-95 duration-700">
        @if (CurrentInsightData.Any())
        {
            <!-- Podium -->
            <div class="grid grid-cols-1 md:grid-cols-3 gap-8 items-end mb-16 max-w-5xl mx-auto px-4">
                @* 2nd Place *@
                @if (CurrentInsightData.Count() > 1)
                {
                    var user = CurrentInsightData.ElementAt(1);
                    <div class="flex flex-col items-center animate-in slide-in-from-bottom-8 duration-700 delay-100">
                        <div class="relative mb-4">
                            <div class="w-24 h-24 rounded-2xl bg-mystic-100 border-2 border-mystic-200 flex items-center justify-center text-mystic-400 text-3xl font-black shadow-lg">
                                @(user.Name.Substring(0, Math.Min(2, user.Name.Length)).ToUpper())
                            </div>
                            <div class="absolute -top-3 -right-3 w-10 h-10 rounded-full bg-slate-300 border-4 border-white flex items-center justify-center text-white font-bold shadow-md">2</div>
                        </div>
                        <h3 class="text-lg font-bold text-mystic-900 text-center truncate w-full">@user.Name</h3>
                        <p class="text-mystic-500 font-bold text-sm">@user.ValueLabel</p>
                        <div class="mt-4 h-32 w-full bg-gradient-to-t from-mystic-100 to-transparent rounded-t-3xl border-x border-t border-mystic-200/50"></div>
                    </div>
                }

                @* 1st Place *@
                @if (CurrentInsightData.Any())
                {
                    var user = CurrentInsightData.ElementAt(0);
                    <div class="flex flex-col items-center relative z-10 animate-in slide-in-from-bottom-12 duration-700">
                        <div class="relative mb-6">
                            <div class="w-32 h-32 rounded-3xl bg-mystic-900 flex items-center justify-center text-white text-4xl font-black shadow-2xl ring-4 ring-mystic-900/10 scale-110">
                                @(user.Name.Substring(0, Math.Min(2, user.Name.Length)).ToUpper())
                            </div>
                            <div class="absolute -top-4 -right-4 w-12 h-12 rounded-full bg-mystic-900 border-4 border-white flex items-center justify-center text-white text-xl font-bold shadow-xl">1</div>
                            <div class="absolute -top-12 left-1/2 -translate-x-1/2 text-mystic-900 font-black tracking-tighter">
                                <svg class="w-10 h-10" fill="currentColor" viewBox="0 0 24 24"><path d="M5 16L3 5L8.5 10L12 4L15.5 10L21 5L19 16H5Z"></path></svg>
                            </div>
                        </div>
                        <h3 class="text-2xl font-black text-mystic-900 text-center truncate w-full">@user.Name</h3>
                        <p class="text-mystic-700 font-black text-lg">@user.ValueLabel</p>
                        <div class="mt-6 h-48 w-full bg-gradient-to-t from-mystic-200 to-transparent rounded-t-[2.5rem] border-x border-t border-mystic-300/30 shadow-2xl shadow-mystic-900/5"></div>
                    </div>
                }

                @* 3rd Place *@
                @if (CurrentInsightData.Count() > 2)
                {
                    var user = CurrentInsightData.ElementAt(2);
                    <div class="flex flex-col items-center animate-in slide-in-from-bottom-6 duration-700 delay-200">
                        <div class="relative mb-4">
                            <div class="w-20 h-20 rounded-2xl bg-mystic-50 border-2 border-mystic-100 flex items-center justify-center text-mystic-300 text-2xl font-black shadow-md">
                                @(user.Name.Substring(0, Math.Min(2, user.Name.Length)).ToUpper())
                            </div>
                            <div class="absolute -top-2 -right-2 w-8 h-8 rounded-full bg-mystic-500 border-4 border-white flex items-center justify-center text-white font-bold shadow-md">3</div>
                        </div>
                        <h3 class="text-base font-bold text-mystic-900 text-center truncate w-full">@user.Name</h3>
                        <p class="text-mystic-400 font-bold text-xs">@user.ValueLabel</p>
                        <div class="mt-4 h-24 w-full bg-gradient-to-t from-mystic-50 to-transparent rounded-t-2xl border-x border-t border-mystic-100/30"></div>
                    </div>
                }
            </div>

            <!-- Full List Table -->
            <div class="card overflow-hidden">
                <div class="p-6 border-b border-mystic-100 bg-mystic-50/50">
                    <h3 class="text-lg font-bold text-mystic-900">Rankings Overview</h3>
                </div>
                <div class="overflow-x-auto">
                    <table class="w-full text-left border-collapse">
                        <thead>
                            <tr class="bg-white border-b border-mystic-100">
                                <th class="px-6 py-4 text-[10px] font-bold text-mystic-400 uppercase tracking-widest">Rank</th>
                                <th class="px-6 py-4 text-[10px] font-bold text-mystic-400 uppercase tracking-widest">Member</th>
                                <th class="px-6 py-4 text-[10px] font-bold text-mystic-400 uppercase tracking-widest">Performance</th>
                                <th class="px-6 py-4 text-[10px] font-bold text-mystic-400 uppercase tracking-widest text-right">Progress</th>
                            </tr>
                        </thead>
                        <tbody class="divide-y divide-mystic-100">
                            @foreach (var (user, index) in CurrentInsightData.Select((u, i) => (u, i)))
                            {
                                <tr class="hover:bg-mystic-50/50 transition-colors group">
                                    <td class="px-6 py-5">
                                        <div class='w-8 h-8 rounded-lg flex items-center justify-center text-sm font-black @(index == 0 ? "bg-mystic-900 text-white shadow-md" : index == 1 ? "bg-mystic-600 text-white" : index == 2 ? "bg-mystic-300 text-mystic-900" : "text-mystic-400")'>
                                            #@(index + 1)
                                        </div>
                                    </td>
                                    <td class="px-6 py-5">
                                        <div class="flex items-center gap-3">
                                            <div class="w-10 h-10 rounded-full bg-mystic-900/5 flex items-center justify-center text-mystic-600 font-bold text-xs border border-mystic-100">
                                                @(user.Name.Substring(0, Math.Min(2, user.Name.Length)).ToUpper())
                                            </div>
                                            <div>
                                                <p class="text-sm font-bold text-mystic-900 group-hover:text-mystic-600 transition-colors">@user.Name</p>
                                                <p class="text-[10px] text-mystic-400 font-medium">Member since @user.JoinedDate.ToString("MMM yyyy")</p>
                                            </div>
                                        </div>
                                    </td>
                                    <td class="px-6 py-5">
                                        <div class="flex flex-col">
                                            <span class="text-sm font-extrabold text-mystic-900">@user.ValueLabel</span>
                                            <span class="text-[10px] text-mystic-500 font-medium">Lifetime Achievement</span>
                                        </div>
                                    </td>
                                    <td class="px-6 py-5">
                                        <div class="w-full bg-mystic-100 h-1.5 rounded-full overflow-hidden max-w-[120px] ml-auto">
                                            <div class="bg-mystic-900 h-full transition-all duration-1000" 
                                                 style="width: @(CalculatePercentage(user.RawValue))%"></div>
                                        </div>
                                    </td>
                                </tr>
                            }
                        </tbody>
                    </table>
                </div>
            </div>
        }
        else
        {
            <div class="py-20 text-center bg-mystic-50 rounded-3xl border-2 border-dashed border-mystic-200">
                <p class="text-mystic-400 font-medium italic">No data available for this insight yet.</p>
            </div>
        }
    </div>
}

@code {
    private bool _isLoading = true;
    private string _activeTab = "Subscribers";
    
    private List<InsightItem> _subscribers = new();
    private List<InsightItem> _loyalty = new();
    private List<InsightItem> _activeReaders = new();

    private IEnumerable<InsightItem> CurrentInsightData => _activeTab switch
    {
        "Subscribers" => _subscribers,
        "Loyalty" => _loyalty,
        "Active" => _activeReaders,
        _ => Enumerable.Empty<InsightItem>()
    };

    protected override async Task OnInitializedAsync()
    {
        await LoadInsightsAsync();
    }

    private async Task LoadInsightsAsync()
    {
        _isLoading = true;
        try
        {
            var users = await ApiClient.GetUsersAsync();
            var borrowings = await ApiClient.GetAllBorrowingsAsync();
            var subscriptions = await ApiClient.GetAllSubscriptionsAsync();
            var memberships = await ApiClient.GetMembershipsAsync();
            var loyaltyHistory = await ApiClient.GetAllMembersPointsHistoryAsync();

            // 1. Top Subscribers (Total Spent)
            var membershipPriceMap = memberships.ToDictionary(m => m.Id, m => m.Price);
            _subscribers = subscriptions
                .GroupBy(s => s.UserId)
                .Select(g => {
                    var user = users.FirstOrDefault(u => u.Id == g.Key);
                    var totalSpent = g.Sum(s => membershipPriceMap.TryGetValue(s.MembershipId, out var price) ? price : 0);
                    return new InsightItem {
                        UserId = g.Key,
                        Name = user?.FullName ?? "Unknown User",
                        JoinedDate = user?.CreatedAt ?? DateTime.MinValue,
                        RawValue = (double)totalSpent,
                        ValueLabel = $"MMK {totalSpent:N0}"
                    };
                })
                .OrderByDescending(i => i.RawValue)
                .ToList();

            // 2. Top Loyalty (Earned Points only)
            _loyalty = loyaltyHistory
                .Select(lh => {
                    var user = users.FirstOrDefault(u => u.Id == lh.UserId);
                    var totalEarned = lh.History.Where(h => h.PointDelta > 0).Sum(h => h.PointDelta);
                    return new InsightItem {
                        UserId = lh.UserId,
                        Name = user?.FullName ?? lh.UserName,
                        JoinedDate = user?.CreatedAt ?? DateTime.MinValue,
                        RawValue = totalEarned,
                        ValueLabel = $"{totalEarned:N0} Points"
                    };
                })
                .OrderByDescending(i => i.RawValue)
                .ToList();

            // 3. Most Active (Approved Returns only)
            _activeReaders = borrowings
                .Where(b => b.Status == "Returned")
                .GroupBy(b => b.UserId)
                .Select(g => {
                    var user = users.FirstOrDefault(u => u.Id == g.Key);
                    var count = g.Count();
                    return new InsightItem {
                        UserId = g.Key,
                        Name = user?.FullName ?? "Unknown User",
                        JoinedDate = user?.CreatedAt ?? DateTime.MinValue,
                        RawValue = count,
                        ValueLabel = $"{count} Completed"
                    };
                })
                .OrderByDescending(i => i.RawValue)
                .ToList();
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error loading insights: {ex.Message}");
        }
        finally
        {
            _isLoading = false;
        }
    }

    private double CalculatePercentage(double value)
    {
        var max = CurrentInsightData.Any() ? CurrentInsightData.Max(i => i.RawValue) : 1;
        if (max == 0) return 0;
        return (value / max) * 100;
    }

    private class InsightItem
    {
        public Guid UserId { get; set; }
        public string Name { get; set; } = "";
        public DateTime JoinedDate { get; set; }
        public double RawValue { get; set; }
        public string ValueLabel { get; set; } = "";
    }
}