using Microsoft.EntityFrameworkCore;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using System.Security.Claims;

var builder = WebApplication.CreateBuilder(args);

// Add CORS
builder.Services.AddCors(options =>
{
    options.AddPolicy("AllowFrontend", policy =>
    {
        policy.WithOrigins("http://localhost:3030")
              .AllowAnyHeader()
              .AllowAnyMethod()
              .AllowCredentials();
    });
});

// Add SQLite Database
builder.Services.AddDbContext<TodoDbContext>(options =>
    options.UseSqlite(builder.Configuration.GetConnectionString("DefaultConnection")));

// Add Keycloak Authentication
builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options =>
    {
        options.Authority = "https://terminus.bluelake.cloud/realms/dalex-immo-dev";
        options.RequireHttpsMetadata = true;
        options.Audience = "dalex-proto";
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuer = true,
            ValidateAudience = false,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true
        };
    });

builder.Services.AddAuthorization();

var app = builder.Build();

// Ensure database is created
using (var scope = app.Services.CreateScope())
{
    var db = scope.ServiceProvider.GetRequiredService<TodoDbContext>();
    db.Database.EnsureCreated();
}

app.UseCors("AllowFrontend");
app.UseAuthentication();
app.UseAuthorization();

// Get all todos for current user
app.MapGet("/api/todos", async (TodoDbContext db, HttpContext context) =>
{
    var userId = context.User.FindFirst(ClaimTypes.NameIdentifier)?.Value 
        ?? context.User.FindFirst("sub")?.Value;
    
    if (string.IsNullOrEmpty(userId))
        return Results.Unauthorized();

    var todos = await db.Todos
        .Where(t => t.UserId == userId)
        .OrderByDescending(t => !t.IsCompleted)
        .ThenBy(t => t.CreatedAt)  // Older todos first (ascending)
        .ToListAsync();

    return Results.Ok(todos);
})
.RequireAuthorization();

// Get recent todos (exclude old completed ones)
app.MapGet("/api/todos/recent", async (TodoDbContext db, HttpContext context) =>
{
    var userId = context.User.FindFirst(ClaimTypes.NameIdentifier)?.Value 
        ?? context.User.FindFirst("sub")?.Value;
    
    if (string.IsNullOrEmpty(userId))
        return Results.Unauthorized();

    var oneWeekAgo = DateTime.UtcNow.AddDays(-7);
    
    // Fetch todos and sort in memory to handle different sorting for completed vs incomplete
    var allTodos = await db.Todos
        .Where(t => t.UserId == userId && 
            (!t.IsCompleted || (t.CompletedAt.HasValue && t.CompletedAt.Value > oneWeekAgo)))
        .ToListAsync();
    
    // Sort: incomplete todos first (by CreatedAt ascending), then completed (by CompletedAt descending)
    var todos = allTodos
        .OrderBy(t => t.IsCompleted)
        .ThenBy(t => !t.IsCompleted ? t.CreatedAt : DateTime.MinValue)  // Older incomplete first
        .ThenByDescending(t => t.IsCompleted ? (t.CompletedAt ?? DateTime.MinValue) : DateTime.MinValue)  // Newer completed first
        .ToList();

    return Results.Ok(todos);
})
.RequireAuthorization();

// Create a new todo
app.MapPost("/api/todos", async (TodoDbContext db, HttpContext context, TodoCreateDto dto) =>
{
    var userId = context.User.FindFirst(ClaimTypes.NameIdentifier)?.Value 
        ?? context.User.FindFirst("sub")?.Value;
    
    if (string.IsNullOrEmpty(userId))
        return Results.Unauthorized();

    var todo = new Todo
    {
        UserId = userId,
        Title = dto.Title,
        Description = dto.Description,
        CreatedAt = DateTime.UtcNow,
        IsCompleted = false
    };

    db.Todos.Add(todo);
    await db.SaveChangesAsync();

    return Results.Created($"/api/todos/{todo.Id}", todo);
})
.RequireAuthorization();

// Update a todo
app.MapPut("/api/todos/{id}", async (TodoDbContext db, HttpContext context, int id, TodoUpdateDto dto) =>
{
    var userId = context.User.FindFirst(ClaimTypes.NameIdentifier)?.Value 
        ?? context.User.FindFirst("sub")?.Value;
    
    if (string.IsNullOrEmpty(userId))
        return Results.Unauthorized();

    var todo = await db.Todos.FindAsync(id);
    
    if (todo == null || todo.UserId != userId)
        return Results.NotFound();

    todo.Title = dto.Title ?? todo.Title;
    todo.Description = dto.Description ?? todo.Description;
    
    if (dto.IsCompleted.HasValue && dto.IsCompleted.Value != todo.IsCompleted)
    {
        todo.IsCompleted = dto.IsCompleted.Value;
        todo.CompletedAt = dto.IsCompleted.Value ? DateTime.UtcNow : null;
    }

    await db.SaveChangesAsync();

    return Results.Ok(todo);
})
.RequireAuthorization();

// Delete a todo
app.MapDelete("/api/todos/{id}", async (TodoDbContext db, HttpContext context, int id) =>
{
    var userId = context.User.FindFirst(ClaimTypes.NameIdentifier)?.Value 
        ?? context.User.FindFirst("sub")?.Value;
    
    if (string.IsNullOrEmpty(userId))
        return Results.Unauthorized();

    var todo = await db.Todos.FindAsync(id);
    
    if (todo == null || todo.UserId != userId)
        return Results.NotFound();

    db.Todos.Remove(todo);
    await db.SaveChangesAsync();

    return Results.NoContent();
})
.RequireAuthorization();

app.Run();

// Models
public class Todo
{
    public int Id { get; set; }
    public string UserId { get; set; } = string.Empty;
    public string Title { get; set; } = string.Empty;
    public string? Description { get; set; }
    public DateTime CreatedAt { get; set; }
    public DateTime? CompletedAt { get; set; }
    public bool IsCompleted { get; set; }
}

public class TodoCreateDto
{
    public string Title { get; set; } = string.Empty;
    public string? Description { get; set; }
}

public class TodoUpdateDto
{
    public string? Title { get; set; }
    public string? Description { get; set; }
    public bool? IsCompleted { get; set; }
}

public class TodoDbContext : DbContext
{
    public TodoDbContext(DbContextOptions<TodoDbContext> options) : base(options) { }

    public DbSet<Todo> Todos => Set<Todo>();

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Todo>(entity =>
        {
            entity.HasKey(e => e.Id);
            entity.Property(e => e.UserId).IsRequired();
            entity.Property(e => e.Title).IsRequired();
            entity.HasIndex(e => e.UserId);
        });
    }
}