using Api.SeaHavenIndustries.Helper;
using Data.SeaHavenIndustries;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace Api.SeaHavenIndustries.Controllers
{
    [ApiController]
    [Route("api/vendor-portal")]
    [Route("api/vendorportal")]
    public class VendorPortalController : Controller
    {
        private const string TokenHeader = "X-Vendor-Token";

        private static readonly string[] VendorViewableStatuses =
            new[] { "Sent", "Acknowledged", "In Progress", "Completed", "Verified", "Cancelled" };

        private readonly ApplicationDbContext _db;
        private readonly VendorPortalTokenService _tokens;

        public VendorPortalController(ApplicationDbContext db, VendorPortalTokenService tokens)
        {
            _db = db;
            _tokens = tokens;
        }

        [HttpGet("session")]
        public async Task<IActionResult> Session()
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            return Ok(new DataResponse
            {
                Status = "Success",
                Data = new
                {
                    vendor.Id,
                    vendor.CompanyName,
                    vendor.ContactName,
                    vendor.Email,
                    vendor.Phone
                }
            });
        }

        [HttpGet("dispatches")]
        public async Task<IActionResult> ListDispatches([FromQuery] string? status = null)
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            var query = _db.Dispatches
                .Include(d => d.WorkOrder).ThenInclude(w => w!.Locations)
                .Where(d => d.VendorId == vendor.Id && (d.IsDeleted == null || d.IsDeleted == false));

            if (!string.IsNullOrWhiteSpace(status))
            {
                query = query.Where(d => d.Status == status);
            }

            var dispatches = await query
                .OrderByDescending(d => d.DispatchedAt ?? d.CreatedDate)
                .Select(d => new
                {
                    d.Id,
                    d.DispatchNumber,
                    d.PONumber,
                    d.Status,
                    d.NTEAmount,
                    d.ScheduledDate,
                    d.CompletedDate,
                    d.DispatchedAt,
                    d.AcknowledgedAt,
                    WorkOrderTitle = d.WorkOrder!.WorkerOrderTitle,
                    InternalWONumber = d.WorkOrder!.InternalWONumber,
                    LocationName = d.WorkOrder!.Locations != null ? d.WorkOrder!.Locations.Name : null,
                    LocationCity = d.WorkOrder!.Locations != null ? d.WorkOrder!.Locations.City : null,
                    LocationState = d.WorkOrder!.Locations != null ? d.WorkOrder!.Locations.State : null
                })
                .ToListAsync();

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

        [HttpGet("dispatches/{id:int}")]
        public async Task<IActionResult> GetDispatch(int id)
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            var dispatch = await LoadVendorDispatchAsync(id, vendor.Id);
            if (dispatch == null) return NotFound(new Response { Status = "Error", Message = "Dispatch not found" });

            var checklist = await _db.DispatchChecklistItems
                .Where(c => c.DispatchId == id && (c.IsDeleted == null || c.IsDeleted == false))
                .OrderBy(c => c.SortOrder)
                .Select(c => new { c.Id, c.ItemText, c.IsCompleted, c.CompletedBy, c.CompletedAt })
                .ToListAsync();

            var signoffs = await _db.DispatchSignoffs
                .Where(s => s.DispatchId == id && (s.IsDeleted == null || s.IsDeleted == false))
                .Select(s => new { s.Id, s.SignoffType, s.Name, s.SignatureMethod, s.SignedAt })
                .ToListAsync();

            var rawComments = await (from c in _db.Comments
                    where c.DispatchId == id
                        && c.CommentType != "internal"
                        && (c.IsDeleted == null || c.IsDeleted == false)
                    join u in _db.Users on c.UserId equals u.Id into users
                    from u in users.DefaultIfEmpty()
                    orderby c.CreatedDate
                    select new
                    {
                        c.Id,
                        c.Commenttext,
                        c.Commenter,
                        c.CommentType,
                        c.CreatedDate,
                        c.UserId,
                        UserFirstName = u != null ? u.FirstName : null,
                        UserLastName = u != null ? u.LastName : null
                    })
                .ToListAsync();

            var comments = rawComments.Select(c =>
            {
                var hasShocUser = !string.IsNullOrWhiteSpace(c.UserId);
                var userName = string.Join(" ", new[] { c.UserFirstName, c.UserLastName }
                    .Where(s => !string.IsNullOrWhiteSpace(s))).Trim();

                string resolvedType;
                string resolvedCommenter;
                if (hasShocUser)
                {
                    resolvedType = "dispatcher";
                    resolvedCommenter = !string.IsNullOrWhiteSpace(userName) ? userName
                        : !string.IsNullOrWhiteSpace(c.Commenter) ? c.Commenter!
                        : "Dispatcher";
                }
                else if (c.CommentType == "customer")
                {
                    resolvedType = "customer";
                    resolvedCommenter = !string.IsNullOrWhiteSpace(c.Commenter) ? c.Commenter! : "Customer";
                }
                else
                {
                    resolvedType = "vendor";
                    resolvedCommenter = !string.IsNullOrWhiteSpace(c.Commenter) ? c.Commenter! : vendor.CompanyName ?? "Vendor";
                }

                return new
                {
                    c.Id,
                    c.Commenttext,
                    Commenter = resolvedCommenter,
                    CommentType = resolvedType,
                    c.CreatedDate
                };
            }).ToList();

            return Ok(new DataResponse
            {
                Status = "Success",
                Data = new
                {
                    dispatch.Id,
                    dispatch.DispatchNumber,
                    dispatch.PONumber,
                    dispatch.Status,
                    dispatch.NTEAmount,
                    dispatch.Description,
                    dispatch.ScheduledDate,
                    dispatch.CompletedDate,
                    dispatch.DispatchedAt,
                    dispatch.AcknowledgedAt,
                    WorkOrder = dispatch.WorkOrder == null ? null : new
                    {
                        dispatch.WorkOrder.Id,
                        dispatch.WorkOrder.InternalWONumber,
                        dispatch.WorkOrder.WorkerOrderTitle,
                        dispatch.WorkOrder.Description,
                        dispatch.WorkOrder.Priority,
                        dispatch.WorkOrder.DueDate,
                        dispatch.WorkOrder.Trade,
                        dispatch.WorkOrder.SubTrade,
                        dispatch.WorkOrder.Problem
                    },
                    Location = dispatch.WorkOrder?.Locations == null ? null : new
                    {
                        dispatch.WorkOrder.Locations.Name,
                        dispatch.WorkOrder.Locations.Address,
                        dispatch.WorkOrder.Locations.City,
                        dispatch.WorkOrder.Locations.State,
                        dispatch.WorkOrder.Locations.ZipCode
                    },
                    Checklist = checklist,
                    Signoffs = signoffs,
                    Comments = comments
                }
            });
        }

        [HttpPost("dispatches/{id:int}/accept")]
        public async Task<IActionResult> Accept(int id)
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            var dispatch = await LoadVendorDispatchAsync(id, vendor.Id);
            if (dispatch == null) return NotFound(new Response { Status = "Error", Message = "Dispatch not found" });

            if (dispatch.Status != "Sent")
            {
                return BadRequest(new Response { Status = "Error", Message = $"Cannot accept a dispatch with status '{dispatch.Status}'" });
            }

            var now = DateTime.UtcNow;
            dispatch.Status = "Acknowledged";
            dispatch.AcknowledgedAt = now;
            dispatch.LastModificationTime = now;

            _db.WorkOrderAuditLogs.Add(new WorkOrderAuditLog
            {
                WorkOrderId = dispatch.WorkOrderId ?? 0,
                FieldName = $"Dispatch {dispatch.DispatchNumber} Status",
                OldValue = "Sent",
                NewValue = "Acknowledged",
                Action = "vendor_accept",
                CreatedAt = now
            });

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

        [HttpPost("dispatches/{id:int}/status")]
        public async Task<IActionResult> ChangeStatus(int id, [FromBody] ChangeStatusRequest body)
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            var dispatch = await LoadVendorDispatchAsync(id, vendor.Id);
            if (dispatch == null) return NotFound(new Response { Status = "Error", Message = "Dispatch not found" });

            var from = dispatch.Status;
            var to = body.Status;
            if (!IsAllowedVendorTransition(from, to))
            {
                return BadRequest(new Response { Status = "Error", Message = $"Transition from '{from}' to '{to}' is not allowed" });
            }

            var now = DateTime.UtcNow;
            dispatch.Status = to;
            dispatch.LastModificationTime = now;
            if (to == "Completed") dispatch.CompletedDate = now;

            _db.WorkOrderAuditLogs.Add(new WorkOrderAuditLog
            {
                WorkOrderId = dispatch.WorkOrderId ?? 0,
                FieldName = $"Dispatch {dispatch.DispatchNumber} Status",
                OldValue = from,
                NewValue = to,
                Action = "vendor_status_change",
                CreatedAt = now
            });

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

        [HttpPost("dispatches/{id:int}/request-cancel")]
        public async Task<IActionResult> RequestCancel(int id, [FromBody] RequestCancelRequest body)
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            var dispatch = await LoadVendorDispatchAsync(id, vendor.Id);
            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 request cancel on a '{dispatch.Status}' dispatch" });
            }

            var now = DateTime.UtcNow;
            var reason = string.IsNullOrWhiteSpace(body?.Reason) ? "(no reason provided)" : body!.Reason!.Trim();

            _db.Comments.Add(new Comments
            {
                DispatchId = id,
                WorkerOrderId = dispatch.WorkOrderId,
                Commenter = vendor.CompanyName,
                CommentType = "vendor",
                RecordType = "cancel_request",
                Commenttext = $"Vendor requested cancellation: {reason}",
                CreatedDate = now
            });

            _db.WorkOrderAuditLogs.Add(new WorkOrderAuditLog
            {
                WorkOrderId = dispatch.WorkOrderId ?? 0,
                FieldName = $"Dispatch {dispatch.DispatchNumber}",
                OldValue = dispatch.Status,
                NewValue = "Cancel Requested",
                Action = "vendor_request_cancel",
                CreatedAt = now
            });

            await _db.SaveChangesAsync();
            return Ok(new DataResponse { Status = "Success", Message = "Cancel request sent to dispatcher" });
        }

        [HttpPost("dispatches/{id:int}/checklist/{itemId:int}")]
        public async Task<IActionResult> UpdateChecklistItem(int id, int itemId, [FromBody] ChecklistUpdateRequest body)
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            var dispatch = await LoadVendorDispatchAsync(id, vendor.Id);
            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 = "Dispatch is locked" });
            }

            var item = await _db.DispatchChecklistItems
                .FirstOrDefaultAsync(c => c.Id == itemId && c.DispatchId == id);
            if (item == null) return NotFound(new Response { Status = "Error", Message = "Checklist item not found" });

            var now = DateTime.UtcNow;
            item.IsCompleted = body.IsCompleted;
            item.CompletedBy = body.IsCompleted ? vendor.CompanyName : null;
            item.CompletedAt = body.IsCompleted ? now : null;
            item.LastModificationTime = now;

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

        [HttpPost("dispatches/{id:int}/signoff")]
        public async Task<IActionResult> AddSignoff(int id, [FromBody] SignoffRequest body)
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            var dispatch = await LoadVendorDispatchAsync(id, vendor.Id);
            if (dispatch == null) return NotFound(new Response { Status = "Error", Message = "Dispatch not found" });

            if (dispatch.Status != "In Progress" && dispatch.Status != "Completed")
            {
                return BadRequest(new Response { Status = "Error", Message = "Signoffs only allowed on In Progress or Completed dispatches" });
            }

            if (string.IsNullOrWhiteSpace(body?.Name) || string.IsNullOrWhiteSpace(body?.Signature))
            {
                return BadRequest(new Response { Status = "Error", Message = "Name and signature are required" });
            }

            var signoffType = (body?.SignoffType ?? "vendor").Trim().ToLowerInvariant();
            if (signoffType != "vendor" && signoffType != "customer")
            {
                return BadRequest(new Response { Status = "Error", Message = "signoffType must be 'vendor' or 'customer'" });
            }

            var existing = await _db.DispatchSignoffs
                .FirstOrDefaultAsync(s => s.DispatchId == id && s.SignoffType == signoffType);
            if (existing != null)
            {
                return BadRequest(new Response { Status = "Error", Message = $"A {signoffType} signoff already exists for this dispatch" });
            }

            var now = DateTime.UtcNow;
            var signoff = new DispatchSignoff
            {
                DispatchId = id,
                SignoffType = signoffType,
                Name = body!.Name,
                Signature = body.Signature,
                SignatureMethod = body.SignatureMethod ?? "drawn",
                SignedAt = now,
                CreatedDate = now
            };
            _db.DispatchSignoffs.Add(signoff);

            _db.WorkOrderAuditLogs.Add(new WorkOrderAuditLog
            {
                WorkOrderId = dispatch.WorkOrderId ?? 0,
                FieldName = $"Dispatch {dispatch.DispatchNumber} Signoff",
                OldValue = null,
                NewValue = $"{(signoffType == "customer" ? "Customer" : "Vendor")}: {body.Name}",
                Action = signoffType == "customer" ? "customer_signoff" : "vendor_signoff",
                CreatedAt = now
            });

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

        [HttpPost("dispatches/{id:int}/comments")]
        public async Task<IActionResult> AddComment(int id, [FromBody] CommentRequest body)
        {
            var vendor = await ResolveVendorAsync();
            if (vendor == null) return Unauthorized(new Response { Status = "Error", Message = "Invalid or expired token" });

            var dispatch = await LoadVendorDispatchAsync(id, vendor.Id);
            if (dispatch == null) return NotFound(new Response { Status = "Error", Message = "Dispatch not found" });

            if (string.IsNullOrWhiteSpace(body?.CommentText))
            {
                return BadRequest(new Response { Status = "Error", Message = "Comment cannot be empty" });
            }

            var now = DateTime.UtcNow;
            var comment = new Comments
            {
                DispatchId = id,
                WorkerOrderId = dispatch.WorkOrderId,
                Commenter = vendor.CompanyName,
                CommentType = "vendor",
                RecordType = "comment",
                Commenttext = body!.CommentText,
                CreatedDate = now
            };
            _db.Comments.Add(comment);
            await _db.SaveChangesAsync();

            return Ok(new DataResponse
            {
                Status = "Success",
                Data = new { comment.Id, comment.Commenttext, comment.Commenter, comment.CreatedDate }
            });
        }

        private async Task<Vendor?> ResolveVendorAsync()
        {
            if (!Request.Headers.TryGetValue(TokenHeader, out var values)) return null;
            var token = values.ToString();
            return await _tokens.ResolveVendorAsync(token);
        }

        private Task<Dispatch?> LoadVendorDispatchAsync(int id, int vendorId)
        {
            return _db.Dispatches
                .Include(d => d.WorkOrder).ThenInclude(w => w!.Locations)
                .FirstOrDefaultAsync(d => d.Id == id
                    && d.VendorId == vendorId
                    && (d.IsDeleted == null || d.IsDeleted == false));
        }

        private static bool IsAllowedVendorTransition(string? from, string? to)
        {
            if (from == "Acknowledged" && to == "In Progress") return true;
            if (from == "In Progress" && to == "Completed") return true;
            return false;
        }

        public class ChangeStatusRequest
        {
            public string? Status { get; set; }
        }

        public class RequestCancelRequest
        {
            public string? Reason { get; set; }
        }

        public class ChecklistUpdateRequest
        {
            public bool IsCompleted { get; set; }
        }

        public class SignoffRequest
        {
            public string? Name { get; set; }
            public string? Signature { get; set; }
            public string? SignatureMethod { get; set; }
            public string? SignoffType { get; set; }
        }

        public class CommentRequest
        {
            public string? CommentText { get; set; }
        }
    }
}