using System.Text;
using Data.SeaHavenIndustries;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using SeaHaven.Services.DTOs;
using SeaHaven.Services.Interfaces;
using System.Security.Claims;

namespace Api.SeaHavenIndustries.Controllers
{
    [Authorize]
    [ApiController]
    [Route("api/vendor-operations")]
    public class VendorOperationsController : ControllerBase
    {
        private readonly IVendorOperationsService _service;

        public VendorOperationsController(IVendorOperationsService service)
        {
            _service = service;
        }

        private string Actor() => User.FindFirstValue(ClaimTypes.NameIdentifier)
            ?? User.Identity?.Name
            ?? "unknown";

        private IActionResult Map<T>(VendorOperationOutcome<T> outcome) => outcome.Kind switch
        {
            VendorOperationOutcomeKind.Ok => Ok(outcome.Value),
            VendorOperationOutcomeKind.NotFound => outcome.Message is null
                ? NotFound()
                : NotFound(new Response { Status = "Error", Message = outcome.Message }),
            VendorOperationOutcomeKind.BadRequest => BadRequest(new Response { Status = "Error", Message = outcome.Message }),
            VendorOperationOutcomeKind.Conflict => Conflict(new Response { Status = "Conflict", Message = outcome.Message }),
            _ => StatusCode(StatusCodes.Status500InternalServerError)
        };

        [HttpGet("notifications")]
        public async Task<IActionResult> GetNotifications(CancellationToken cancellationToken)
        {
            var result = await _service.GetNotificationsAsync(cancellationToken);
            return Ok(new { result.GeneratedAt, result.Items });
        }

        [HttpGet("availability")]
        public async Task<IActionResult> GetAvailability(
            [FromQuery] DateTime? start,
            [FromQuery] DateTime? end,
            [FromQuery] int? locationId,
            [FromQuery] string? trade,
            CancellationToken cancellationToken)
        {
            var outcome = await _service.GetAvailabilityAsync(start, end, locationId, trade, cancellationToken);
            return Map(outcome);
        }

        [HttpPut("vendors/{vendorId:int}/availability")]
        public async Task<IActionResult> UpdateAvailability(int vendorId, [FromBody] VendorAvailabilityRequest body, CancellationToken cancellationToken)
        {
            var outcome = await _service.UpdateAvailabilityAsync(vendorId, body?.Status, Actor(), cancellationToken);
            return Map(outcome);
        }

        [HttpGet("sites/{locationId:int}/preferred-vendors")]
        public async Task<IActionResult> GetSitePreferences(int locationId, CancellationToken cancellationToken)
        {
            var preferences = await _service.GetSitePreferencesAsync(locationId, cancellationToken);
            return Ok(preferences);
        }

        [HttpPut("sites/{locationId:int}/preferred-vendors")]
        public async Task<IActionResult> ReplaceSitePreferences(int locationId, [FromBody] List<SitePreferenceRequest> body, CancellationToken cancellationToken)
        {
            var outcome = await _service.ReplaceSitePreferencesAsync(locationId, body ?? new List<SitePreferenceRequest>(), Actor(), cancellationToken);
            return Map(outcome);
        }

        [HttpPut("documents/{documentId:int}/review")]
        public async Task<IActionResult> ReviewDocument(int documentId, [FromBody] DocumentReviewRequest body, CancellationToken cancellationToken)
        {
            var outcome = await _service.ReviewDocumentAsync(documentId, body ?? new DocumentReviewRequest(), Actor(), cancellationToken);
            return Map(outcome);
        }

        [HttpPut("dispatches/{dispatchId:int}/commercial-status")]
        public async Task<IActionResult> UpdateCommercialStatus(int dispatchId, [FromBody] CommercialStatusRequest body, CancellationToken cancellationToken)
        {
            var outcome = await _service.UpdateCommercialStatusAsync(dispatchId, body ?? new CommercialStatusRequest(), Actor(), cancellationToken);
            return Map(outcome);
        }

        [HttpPut("work-orders/{workOrderId:int}/assignment")]
        public async Task<IActionResult> AssignVendor(int workOrderId, [FromBody] VendorAssignmentRequest body, CancellationToken cancellationToken)
        {
            var outcome = await _service.AssignVendorAsync(workOrderId, body ?? new VendorAssignmentRequest(), Actor(), cancellationToken);
            return Map(outcome);
        }

        [HttpGet("insights")]
        public async Task<IActionResult> GetInsights(
            [FromQuery] DateTime? from,
            [FromQuery] DateTime? to,
            [FromQuery] int? locationId,
            [FromQuery] string? trade,
            [FromQuery] int? vendorId,
            CancellationToken cancellationToken)
        {
            var rows = await _service.GetInsightRowsAsync(from, to, locationId, trade, vendorId, cancellationToken);
            return Ok(new
            {
                GeneratedAt = _service.UtcNow,
                Filters = new { from, to, locationId, trade, vendorId },
                MetricDefinitions = MetricDefinitions(),
                Data = rows
            });
        }

        [HttpGet("insights.csv")]
        public async Task<IActionResult> ExportInsightsCsv(
            [FromQuery] DateTime? from,
            [FromQuery] DateTime? to,
            [FromQuery] int? locationId,
            [FromQuery] string? trade,
            [FromQuery] int? vendorId,
            CancellationToken cancellationToken)
        {
            var rows = await _service.GetInsightRowsAsync(from, to, locationId, trade, vendorId, cancellationToken);
            var csv = new StringBuilder("VendorId,Vendor,CompletedJobs,CancellationRefusalRate,OnTimeArrivalRate,OnTimeCompletionRate,AverageCycleHours\n");
            foreach (var row in rows)
            {
                csv.AppendLine(string.Join(",",
                    row.VendorId,
                    Csv(row.Vendor),
                    row.CompletedJobs,
                    row.CancellationRefusalRate.ToString("0.####"),
                    row.OnTimeArrivalRate.ToString("0.####"),
                    row.OnTimeCompletionRate.ToString("0.####"),
                    row.AverageCycleHours?.ToString("0.##") ?? ""));
            }
            return File(Encoding.UTF8.GetBytes(csv.ToString()), "text/csv", $"vendor-insights-{_service.UtcNow:yyyyMMddHHmmss}.csv");
        }

        [HttpGet("insights.pdf")]
        public async Task<IActionResult> ExportInsightsPdf(
            [FromQuery] DateTime? from,
            [FromQuery] DateTime? to,
            [FromQuery] int? locationId,
            [FromQuery] string? trade,
            [FromQuery] int? vendorId,
            CancellationToken cancellationToken)
        {
            var rows = await _service.GetInsightRowsAsync(from, to, locationId, trade, vendorId, cancellationToken);
            var lines = new List<string>
            {
                "Vendor Performance Insights",
                $"Generated: {_service.UtcNow:u}",
                $"Filters: from={from:u}; to={to:u}; site={locationId}; trade={trade}; vendor={vendorId}",
                "Definitions: completed jobs; cancellation/refusal rate; on-time acknowledgement; on-time completion; average dispatch-to-completion hours."
            };
            lines.AddRange(rows.Take(35).Select(row =>
                $"{row.Vendor}: completed {row.CompletedJobs}; cancel/refusal {row.CancellationRefusalRate:P1}; arrival {row.OnTimeArrivalRate:P1}; completion {row.OnTimeCompletionRate:P1}; cycle {row.AverageCycleHours:0.0}h"));
            return File(SimplePdf(lines), "application/pdf", $"vendor-insights-{_service.UtcNow:yyyyMMddHHmmss}.pdf");
        }

        private static string Csv(string value)
        {
            var spreadsheetSafe = value.Length > 0 && "=+-@\t\r".Contains(value[0])
                ? $"'{value}"
                : value;
            return $"\"{spreadsheetSafe.Replace("\"", "\"\"")}\"";
        }

        private static object MetricDefinitions() => new
        {
            CompletedJobs = "Dispatches with Completed or Verified status.",
            CancellationRefusalRate = "Cancelled, Canceled, or Refused dispatches divided by all dispatches.",
            OnTimeArrivalRate = "Acknowledgements at or before scheduled time divided by dispatches with both timestamps.",
            OnTimeCompletionRate = "Completions at or before the work-order due date divided by completed dispatches with a due date.",
            AverageCycleHours = "Average elapsed hours from dispatch to completion."
        };

        private static byte[] SimplePdf(IEnumerable<string> lines)
        {
            var escaped = lines.Select(line => line.Replace("\\", "\\\\").Replace("(", "\\(").Replace(")", "\\)"));
            var content = "BT /F1 10 Tf 40 760 Td 13 TL "
                + string.Join(" T* ", escaped.Select(line => $"({line}) Tj"))
                + " ET";
            var objects = new[]
            {
                "<< /Type /Catalog /Pages 2 0 R >>",
                "<< /Type /Pages /Kids [3 0 R] /Count 1 >>",
                "<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Resources << /Font << /F1 5 0 R >> >> /Contents 4 0 R >>",
                $"<< /Length {Encoding.ASCII.GetByteCount(content)} >>\nstream\n{content}\nendstream",
                "<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>"
            };
            var builder = new StringBuilder("%PDF-1.4\n");
            var offsets = new List<int> { 0 };
            for (var index = 0; index < objects.Length; index++)
            {
                offsets.Add(Encoding.ASCII.GetByteCount(builder.ToString()));
                builder.Append($"{index + 1} 0 obj\n{objects[index]}\nendobj\n");
            }
            var xrefOffset = Encoding.ASCII.GetByteCount(builder.ToString());
            builder.Append($"xref\n0 {objects.Length + 1}\n0000000000 65535 f \n");
            foreach (var offset in offsets.Skip(1)) builder.Append($"{offset:D10} 00000 n \n");
            builder.Append($"trailer << /Size {objects.Length + 1} /Root 1 0 R >>\nstartxref\n{xrefOffset}\n%%EOF");
            return Encoding.ASCII.GetBytes(builder.ToString());
        }
    }
}