using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using LingAdmin.API.Data;
using LingAdmin.API.Models;
using LingAdmin.API.DTOs;
using Dapr.Client;

namespace LingAdmin.API.Controllers;

[ApiController]
[Route("api/[controller]")]
public class RequisitionsController : ControllerBase
{
    private readonly AppDbContext _context;
    private readonly DaprClient _daprClient;
    private readonly ILogger<RequisitionsController> _logger;

    public RequisitionsController(AppDbContext context, DaprClient daprClient, ILogger<RequisitionsController> logger)
    {
        _context = context;
        _daprClient = daprClient;
        _logger = logger;
    }

    [HttpGet]
    public async Task<ActionResult<ApiResponse<List<object>>>> GetRequisitions()
    {
        try
        {
            var requisitions = await _context.Requisitions
                .Select(r => new
                {
                    id = r.Id,
                    reqNo = r.ReqNo,
                    requester = r.Requester,
                    department = r.Department,
                    date = r.Date.ToString("yyyy-MM-dd"),
                    status = r.Status,
                    totalAmount = r.TotalAmount
                })
                .ToListAsync();

            return Ok(ApiResponse<List<object>>.Success(requisitions.Cast<object>().ToList()));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error retrieving requisitions");
            return StatusCode(500, ApiResponse<List<object>>.Error("Internal server error", 500));
        }
    }

    [HttpGet("{id}")]
    public async Task<ActionResult<ApiResponse<object>>> GetRequisition(int id)
    {
        try
        {
            var requisition = await _context.Requisitions
                .Include(r => r.Items)
                .FirstOrDefaultAsync(r => r.Id == id);

            if (requisition == null)
            {
                return NotFound(ApiResponse<object>.Error("Requisition not found", 404));
            }

            var result = new
            {
                id = requisition.Id,
                reqNo = requisition.ReqNo,
                requester = requisition.Requester,
                department = requisition.Department,
                date = requisition.Date.ToString("yyyy-MM-dd"),
                status = requisition.Status,
                description = requisition.Description,
                items = requisition.Items.Select(i => new
                {
                    id = i.Id,
                    itemName = i.ItemName,
                    quantity = i.Quantity,
                    price = i.Price
                }).ToList()
            };

            return Ok(ApiResponse<object>.Success(result));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error retrieving requisition {Id}", id);
            return StatusCode(500, ApiResponse<object>.Error("Internal server error", 500));
        }
    }

    [HttpPost]
    public async Task<ActionResult<ApiResponse<object>>> CreateRequisition(CreateRequisitionDto dto)
    {
        try
        {
            // Generate next requisition number
            var lastReqNo = await _context.Requisitions
                .OrderByDescending(r => r.Id)
                .Select(r => r.ReqNo)
                .FirstOrDefaultAsync();

            int nextNumber = 1;
            if (!string.IsNullOrEmpty(lastReqNo))
            {
                var numberPart = lastReqNo.Split('-').LastOrDefault();
                if (int.TryParse(numberPart, out int current))
                {
                    nextNumber = current + 1;
                }
            }

            var reqNo = $"PR-{DateTime.Now.Year}{nextNumber:D3}";

            var requisition = new Requisition
            {
                ReqNo = reqNo,
                Requester = dto.Requester,
                Department = dto.Department,
                Date = dto.Date,
                Status = dto.Status,
                Description = dto.Description,
                TotalAmount = dto.Items.Sum(i => i.Quantity * i.Price)
            };

            foreach (var itemDto in dto.Items)
            {
                requisition.Items.Add(new RequisitionItem
                {
                    ItemName = itemDto.ItemName,
                    Quantity = itemDto.Quantity,
                    Price = itemDto.Price
                });
            }

            _context.Requisitions.Add(requisition);
            await _context.SaveChangesAsync();

            // Publish event via Dapr
            try
            {
                await _daprClient.PublishEventAsync("pubsub", "requisition-created", new
                {
                    id = requisition.Id,
                    reqNo = requisition.ReqNo,
                    requester = requisition.Requester,
                    totalAmount = requisition.TotalAmount
                });
            }
            catch (Exception pubEx)
            {
                _logger.LogWarning(pubEx, "Failed to publish requisition-created event");
            }

            return Ok(ApiResponse<object>.Success(new { id = requisition.Id }));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error creating requisition");
            return StatusCode(500, ApiResponse<object>.Error("Internal server error", 500));
        }
    }

    [HttpPut("{id}")]
    public async Task<ActionResult<ApiResponse<object>>> UpdateRequisition(int id, CreateRequisitionDto dto)
    {
        try
        {
            var requisition = await _context.Requisitions
                .Include(r => r.Items)
                .FirstOrDefaultAsync(r => r.Id == id);

            if (requisition == null)
            {
                return NotFound(ApiResponse<object>.Error("Requisition not found", 404));
            }

            requisition.Requester = dto.Requester;
            requisition.Department = dto.Department;
            requisition.Date = dto.Date;
            requisition.Status = dto.Status;
            requisition.Description = dto.Description;

            // Remove old items and add new ones
            _context.RequisitionItems.RemoveRange(requisition.Items);
            requisition.Items.Clear();

            foreach (var itemDto in dto.Items)
            {
                requisition.Items.Add(new RequisitionItem
                {
                    ItemName = itemDto.ItemName,
                    Quantity = itemDto.Quantity,
                    Price = itemDto.Price
                });
            }

            requisition.TotalAmount = dto.Items.Sum(i => i.Quantity * i.Price);

            await _context.SaveChangesAsync();

            return Ok(ApiResponse<object>.Success(new { id = requisition.Id }));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error updating requisition {Id}", id);
            return StatusCode(500, ApiResponse<object>.Error("Internal server error", 500));
        }
    }

    [HttpDelete("{id}")]
    public async Task<ActionResult<ApiResponse<object>>> DeleteRequisition(int id)
    {
        try
        {
            var requisition = await _context.Requisitions.FindAsync(id);
            if (requisition == null)
            {
                return NotFound(ApiResponse<object>.Error("Requisition not found", 404));
            }

            _context.Requisitions.Remove(requisition);
            await _context.SaveChangesAsync();

            return Ok(ApiResponse<object>.Success(new { }));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error deleting requisition {Id}", id);
            return StatusCode(500, ApiResponse<object>.Error("Internal server error", 500));
        }
    }
}