using Data.SeaHavenIndustries;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using System.Security.Claims;

namespace Api.SeaHavenIndustries.Controllers
{
    [Authorize]
    [ApiController]
    [Route("api/[controller]")]
    [Route("api/uplifts")]
    public class UpliftController : Controller
    {
        private readonly ApplicationDbContext _db;
        private readonly IConfiguration _config;

        public UpliftController(ApplicationDbContext db, IConfiguration config)
        {
            _db = db;
            _config = config;
        }

        [HttpGet]
        public async Task<IActionResult> List([FromQuery] string? status = "Pending", [FromQuery] int? tier = null, [FromQuery] int page = 1, [FromQuery] int pageSize = 25)
        {
            var query = from u in _db.DispatchUpliftRequests
                        join d in _db.Dispatches on u.DispatchId equals d.Id
                        join v in _db.Vendors on d.VendorId equals v.Id into vendors
                        from v in vendors.DefaultIfEmpty()
                        where (u.IsDeleted == null || u.IsDeleted == false)
                        select new { u, d, v };

            if (!string.IsNullOrWhiteSpace(status))
                query = query.Where(x => x.u.Status == status);
            if (tier.HasValue)
                query = query.Where(x => x.u.RequiredTier == tier.Value);

            var total = await query.CountAsync();

            var raw = await query
                .OrderByDescending(x => x.u.CreatedDate)
                .Skip((Math.Max(page, 1) - 1) * pageSize)
                .Take(pageSize)
                .Select(x => new
                {
                    x.u.Id,
                    DispatchId = x.d.Id,
                    x.d.DispatchNumber,
                    x.d.PONumber,
                    WorkOrderId = x.d.WorkOrderId,
                    VendorCompanyName = x.v != null ? x.v.CompanyName : x.u.RequestedByVendorName,
                    x.u.CurrentNTE,
                    x.u.RequestedNTE,
                    x.u.VendorReason,
                    x.u.RequiredTier,
                    x.u.Status,
                    RequestedAt = x.u.CreatedDate,
                    x.u.DecidedAt,
                    x.u.DecisionNote
                })
                .ToListAsync();

            var items = raw.Select(r => new
            {
                r.Id,
                r.DispatchId,
                r.DispatchNumber,
                r.PONumber,
                r.WorkOrderId,
                r.VendorCompanyName,
                r.CurrentNTE,
                r.RequestedNTE,
                Delta = r.RequestedNTE - (r.CurrentNTE ?? 0m),
                r.VendorReason,
                r.RequiredTier,
                r.Status,
                r.RequestedAt,
                r.DecidedAt,
                r.DecisionNote,
                CanDecide = UserCanApprove(r.RequiredTier)
            }).ToList();

            return Ok(new DataResponse
            {
                Status = "Success",
                Data = new { total, page, pageSize, items }
            });
        }

        [HttpGet("dispatch/{dispatchId:int}")]
        public async Task<IActionResult> ListForDispatch(int dispatchId)
        {
            var rows = await (from u in _db.DispatchUpliftRequests
                              where u.DispatchId == dispatchId && (u.IsDeleted == null || u.IsDeleted == false)
                              join dec in _db.Users on u.DecidedByUserId equals dec.Id into decs
                              from dec in decs.DefaultIfEmpty()
                              orderby u.CreatedDate descending
                              select new
                              {
                                  u.Id,
                                  u.DispatchId,
                                  u.CurrentNTE,
                                  u.RequestedNTE,
                                  Delta = u.RequestedNTE - (u.CurrentNTE ?? 0m),
                                  u.VendorReason,
                                  u.Status,
                                  u.RequiredTier,
                                  u.RequestedByVendorName,
                                  RequestedAt = u.CreatedDate,
                                  u.DecidedAt,
                                  u.DecisionNote,
                                  DecidedByFirstName = dec != null ? dec.FirstName : null,
                                  DecidedByLastName = dec != null ? dec.LastName : null
                              }).ToListAsync();

            var items = rows.Select(r => new
            {
                r.Id,
                r.DispatchId,
                r.CurrentNTE,
                r.RequestedNTE,
                r.Delta,
                r.VendorReason,
                r.Status,
                r.RequiredTier,
                r.RequestedByVendorName,
                r.RequestedAt,
                r.DecidedAt,
                r.DecisionNote,
                DecidedByName = string.Join(" ", new[] { r.DecidedByFirstName, r.DecidedByLastName }
                    .Where(s => !string.IsNullOrWhiteSpace(s))).Trim(),
                CanDecide = UserCanApprove(r.RequiredTier)
            }).ToList();

            return Ok(new DataResponse { Status = "Success", Data = items });
        }

        [HttpPost("{id:int}/approve")]
        public async Task<IActionResult> Approve(int id, [FromBody] DecisionRequest? body)
        {
            var req = await _db.DispatchUpliftRequests.FirstOrDefaultAsync(u => u.Id == id);
            if (req == null) return NotFound(new Response { Status = "Error", Message = "Uplift request not found" });
            if (req.Status != "Pending") return BadRequest(new Response { Status = "Error", Message = $"Cannot approve a '{req.Status}' request" });
            if (!UserCanApprove(req.RequiredTier))
                return StatusCode(403, new Response { Status = "Error", Message = $"Approval requires a Tier {req.RequiredTier} role" });

            var dispatch = await _db.Dispatches.FirstOrDefaultAsync(d => d.Id == req.DispatchId);
            if (dispatch == null) return NotFound(new Response { Status = "Error", Message = "Dispatch not found" });
            if (dispatch.Status == "Verified" || dispatch.Status == "Cancelled")
                return BadRequest(new Response { Status = "Error", Message = $"Cannot approve uplift on a '{dispatch.Status}' dispatch" });

            var userId = User.FindFirst(ClaimTypes.NameIdentifier)?.Value;
            var now = DateTime.UtcNow;
            var oldNTE = dispatch.NTEAmount ?? 0m;

            dispatch.NTEAmount = req.RequestedNTE;
            dispatch.LastModificationTime = now;

            req.Status = "Approved";
            req.DecidedAt = now;
            req.DecidedByUserId = userId;
            req.DecisionNote = string.IsNullOrWhiteSpace(body?.Note) ? null : body!.Note!.Trim();
            req.LastModificationTime = now;

            _db.WorkOrderAuditLogs.Add(new WorkOrderAuditLog
            {
                WorkOrderId = dispatch.WorkOrderId ?? 0,
                UserId = userId,
                FieldName = $"Dispatch {dispatch.DispatchNumber} NTE",
                OldValue = $"${oldNTE:F2}",
                NewValue = $"${req.RequestedNTE:F2}",
                Action = "uplift_approved",
                CreatedAt = now
            });

            await _db.SaveChangesAsync();
            return Ok(new DataResponse { Status = "Success", Data = new { req.Id, req.Status, dispatch.NTEAmount } });
        }

        [HttpPost("{id:int}/deny")]
        public async Task<IActionResult> Deny(int id, [FromBody] DecisionRequest body)
        {
            if (body == null || string.IsNullOrWhiteSpace(body.Note))
                return BadRequest(new Response { Status = "Error", Message = "A note is required when denying" });

            var req = await _db.DispatchUpliftRequests.FirstOrDefaultAsync(u => u.Id == id);
            if (req == null) return NotFound(new Response { Status = "Error", Message = "Uplift request not found" });
            if (req.Status != "Pending") return BadRequest(new Response { Status = "Error", Message = $"Cannot deny a '{req.Status}' request" });
            if (!UserCanApprove(req.RequiredTier))
                return StatusCode(403, new Response { Status = "Error", Message = $"Decision requires a Tier {req.RequiredTier} role" });

            var dispatch = await _db.Dispatches.FirstOrDefaultAsync(d => d.Id == req.DispatchId);

            var userId = User.FindFirst(ClaimTypes.NameIdentifier)?.Value;
            var now = DateTime.UtcNow;

            req.Status = "Denied";
            req.DecidedAt = now;
            req.DecidedByUserId = userId;
            req.DecisionNote = body.Note!.Trim();
            req.LastModificationTime = now;

            _db.WorkOrderAuditLogs.Add(new WorkOrderAuditLog
            {
                WorkOrderId = dispatch?.WorkOrderId ?? 0,
                UserId = userId,
                FieldName = $"Dispatch {dispatch?.DispatchNumber} Uplift",
                OldValue = "Pending",
                NewValue = "Denied",
                Action = "uplift_denied",
                CreatedAt = now
            });

            await _db.SaveChangesAsync();
            return Ok(new DataResponse { Status = "Success", Data = new { req.Id, req.Status } });
        }

        [HttpGet("can-approve")]
        public IActionResult CanApprove([FromQuery] int tier)
        {
            return Ok(new DataResponse { Status = "Success", Data = new { canApprove = UserCanApprove(tier) } });
        }

        private bool UserCanApprove(int requiredTier)
        {
            var key = $"Approvals:Tier{requiredTier}Roles";
            var roles = _config.GetSection(key).Get<string[]>() ?? Array.Empty<string>();
            foreach (var r in roles)
            {
                if (!string.IsNullOrWhiteSpace(r) && User.IsInRole(r)) return true;
            }
            return false;
        }

        public class DecisionRequest
        {
            public string? Note { get; set; }
        }
    }
}