using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using Api.SeaHavenIndustries.Options;
using Data.SeaHavenIndustries;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;

namespace Api.SeaHavenIndustries.Controllers
{
    [Authorize(Roles = "Admin")]
    [ApiController]
    [Route("api/[controller]")]
    public class SyncController : Controller
    {
        private readonly ApplicationDbContext _db;
        private readonly AmazonDynamoDBClient _dynamo;
        private readonly SyncOptions _syncOptions;
        private const string WO_TABLE = "WorkOrders";
        private const string COMMENTS_TABLE = "WorkOrderComments";
        private const string VENDOR_REPLIES_TABLE = "VendorReplies";

        public SyncController(ApplicationDbContext db, IOptions<SyncOptions> syncOptions)
        {
            _db = db;
            _syncOptions = syncOptions.Value;
            _dynamo = new AmazonDynamoDBClient(Amazon.RegionEndpoint.USEast1);
        }

        private IActionResult? SyncDisabledResult()
        {
            if (_syncOptions.Enabled)
                return null;

            return StatusCode(StatusCodes.Status503ServiceUnavailable, new
            {
                message = "DynamoDB sync bridge is disabled. Use POST /api/workorders/ingest."
            });
        }

        [HttpPost("WorkOrders")]
        public async Task<IActionResult> SyncWorkOrders()
        {
            if (SyncDisabledResult() is { } disabled)
                return disabled;
            var synced = 0;
            var created = 0;
            var updated = 0;
            var locationsCreated = 0;

            var lastInternalWO = await _db.workOrders
                .Where(w => w.InternalWONumber != null && w.InternalWONumber != "")
                .OrderByDescending(w => w.InternalWONumber)
                .Select(w => w.InternalWONumber)
                .FirstOrDefaultAsync();
            int nextInternal = 10000001;
            if (lastInternalWO != null && int.TryParse(lastInternalWO, out var parsed))
                nextInternal = parsed + 1;

            Dictionary<string, AttributeValue>? lastKey = null;

            do
            {
                var request = new ScanRequest
                {
                    TableName = WO_TABLE,
                    Limit = 100,
                    ExclusiveStartKey = lastKey
                };

                var response = await _dynamo.ScanAsync(request);

                foreach (var item in response.Items)
                {
                    var externalId = GetString(item, "work_order_id");
                    if (string.IsNullOrEmpty(externalId)) continue;

                    var existing = await _db.workOrders
                        .FirstOrDefaultAsync(w => w.ExternalWorkOrderId == externalId);

                    var (locationId, locationWasCreated) = await ResolveLocationId(
                        GetString(item, "site_code"),
                        GetString(item, "building"),
                        GetString(item, "address"));

                    if (locationWasCreated)
                        locationsCreated++;

                    if (existing == null)
                    {
                        var wo = new WorkOrder
                        {
                            InternalWONumber = (nextInternal++).ToString("D8"),
                            ExternalWorkOrderId = externalId,
                            WorkerOrderNumber = externalId,
                            WorkerOrderTitle = GetString(item, "description"),
                            Description = GetString(item, "description"),
                            Status = MapStatus(GetString(item, "wo_status")),
                            Priority = MapSeverityToPriority(GetString(item, "severity")),
                            Severity = GetString(item, "severity"),
                            Customer = GetString(item, "customer"),
                            SiteCode = GetString(item, "site_code"),
                            Building = GetString(item, "building"),
                            LocationId = locationId,
                            DueDate = ParseDate(GetString(item, "due_date")),
                            DateReported = ParseDate(GetString(item, "date_reported")),
                            ScheduledStart = ParseDate(GetString(item, "scheduled_start")),
                            AssignTo = null,
                            SourceEmailS3Key = GetString(item, "source_email_s3_key"),
                            CreatedDate = ParseDate(GetString(item, "created_at")) ?? DateTime.UtcNow,
                            istemplate = false
                        };
                        _db.workOrders.Add(wo);
                        created++;
                    }
                    else
                    {
                        existing.WorkerOrderTitle = GetString(item, "description") ?? existing.WorkerOrderTitle;
                        existing.Description = GetString(item, "description") ?? existing.Description;
                        existing.Status = MapStatus(GetString(item, "wo_status")) ?? existing.Status;
                        existing.Priority = MapSeverityToPriority(GetString(item, "severity")) ?? existing.Priority;
                        existing.Severity = GetString(item, "severity") ?? existing.Severity;
                        existing.SiteCode = GetString(item, "site_code") ?? existing.SiteCode;
                        existing.Building = GetString(item, "building") ?? existing.Building;
                        existing.LocationId = locationId ?? existing.LocationId;
                        existing.DueDate = ParseDate(GetString(item, "due_date")) ?? existing.DueDate;
                        existing.DateReported = ParseDate(GetString(item, "date_reported")) ?? existing.DateReported;
                        existing.ScheduledStart = ParseDate(GetString(item, "scheduled_start")) ?? existing.ScheduledStart;
                        existing.SourceEmailS3Key = GetString(item, "source_email_s3_key") ?? existing.SourceEmailS3Key;
                        updated++;
                    }

                    synced++;

                    if (synced % 100 == 0)
                        await _db.SaveChangesAsync();
                }

                lastKey = response.LastEvaluatedKey;

            } while (lastKey != null && lastKey.Count > 0);

            await _db.SaveChangesAsync();

            return Ok(new
            {
                synced,
                created,
                updated,
                locationsCreated = await _db.Locations.CountAsync()
            });
        }

        [HttpPost("Comments")]
        public async Task<IActionResult> SyncComments()
        {
            if (SyncDisabledResult() is { } disabled)
                return disabled;

            var synced = 0;
            var created = 0;
            var skipped = 0;
            Dictionary<string, AttributeValue>? lastKey = null;

            do
            {
                var request = new ScanRequest
                {
                    TableName = COMMENTS_TABLE,
                    Limit = 100,
                    ExclusiveStartKey = lastKey
                };

                var response = await _dynamo.ScanAsync(request);

                foreach (var item in response.Items)
                {
                    var externalCommentId = GetString(item, "comment_id");
                    var externalWoId = GetString(item, "work_order_id");

                    if (string.IsNullOrEmpty(externalCommentId) || string.IsNullOrEmpty(externalWoId))
                        continue;

                    var alreadyExists = await _db.Comments
                        .AnyAsync(c => c.ExternalCommentId == externalCommentId);

                    if (alreadyExists)
                    {
                        skipped++;
                        synced++;
                        continue;
                    }

                    var workOrder = await _db.workOrders
                        .FirstOrDefaultAsync(w => w.ExternalWorkOrderId == externalWoId);

                    if (workOrder == null)
                    {
                        skipped++;
                        continue;
                    }

                    var comment = new Comments
                    {
                        ExternalCommentId = externalCommentId,
                        WorkerOrderId = workOrder.Id,
                        Commenttext = GetString(item, "text"),
                        Commenter = GetString(item, "commenter"),
                        RecordType = GetString(item, "record_type"),
                        CommentType = "customer",
                        CreatedDate = ParseDate(GetString(item, "created_at")) ?? DateTime.UtcNow,
                    };

                    _db.Comments.Add(comment);
                    created++;
                    synced++;

                    if (synced % 100 == 0)
                        await _db.SaveChangesAsync();
                }

                lastKey = response.LastEvaluatedKey;

            } while (lastKey != null && lastKey.Count > 0);

            await _db.SaveChangesAsync();

            return Ok(new { synced, created, skipped });
        }

        [HttpPost("BackfillInternalWONumbers")]
        public async Task<IActionResult> BackfillInternalWONumbers()
        {
            if (SyncDisabledResult() is { } disabled)
                return disabled;

            var wosMissing = await _db.workOrders
                .Where(w => w.InternalWONumber == null || w.InternalWONumber == "")
                .OrderBy(w => w.Id)
                .ToListAsync();

            if (wosMissing.Count == 0)
                return Ok(new { updated = 0 });

            var lastWO = await _db.workOrders
                .Where(w => w.InternalWONumber != null && w.InternalWONumber != "")
                .OrderByDescending(w => w.InternalWONumber)
                .Select(w => w.InternalWONumber)
                .FirstOrDefaultAsync();

            int next = 10000001;
            if (lastWO != null && int.TryParse(lastWO, out var lastNum))
                next = lastNum + 1;

            foreach (var wo in wosMissing)
            {
                wo.InternalWONumber = next.ToString("D8");
                next++;
            }

            await _db.SaveChangesAsync();
            return Ok(new { updated = wosMissing.Count });
        }

        [HttpPost("BackfillDispatchNumbers")]
        public async Task<IActionResult> BackfillDispatchNumbers()
        {
            if (SyncDisabledResult() is { } disabled)
                return disabled;

            var missing = await _db.Dispatches
                .Where(d => d.DispatchNumber == null || d.DispatchNumber == "")
                .OrderBy(d => d.Id)
                .ToListAsync();
            if (missing.Count == 0) return Ok(new { updated = 0 });

            int next = 1;
            var last = await _db.Dispatches
                .Where(d => d.DispatchNumber != null && d.DispatchNumber != "")
                .OrderByDescending(d => d.DispatchNumber)
                .Select(d => d.DispatchNumber)
                .FirstOrDefaultAsync();
            if (last != null && last.StartsWith("DSP-") && int.TryParse(last.Substring(4), out var n))
                next = n + 1;

            foreach (var d in missing)
            {
                d.DispatchNumber = $"DSP-{next:D5}";
                next++;
            }
            await _db.SaveChangesAsync();
            return Ok(new { updated = missing.Count });
        }

        [HttpPost("VendorReplies")]
        public async Task<IActionResult> SyncVendorReplies()
        {
            if (SyncDisabledResult() is { } disabled)
                return disabled;

            var synced = 0;
            var created = 0;
            var skipped = 0;
            Dictionary<string, AttributeValue>? lastKey = null;

            do
            {
                var request = new ScanRequest
                {
                    TableName = VENDOR_REPLIES_TABLE,
                    Limit = 100,
                    ExclusiveStartKey = lastKey
                };

                var response = await _dynamo.ScanAsync(request);

                foreach (var item in response.Items)
                {
                    var replyId = GetString(item, "reply_id");
                    var woNumber = GetString(item, "internal_wo_number");
                    var dispatchNumber = GetString(item, "dispatch_number");

                    if (string.IsNullOrEmpty(replyId) || string.IsNullOrEmpty(woNumber))
                        continue;

                    var alreadyExists = await _db.Comments
                        .AnyAsync(c => c.ExternalCommentId == replyId);
                    if (alreadyExists) { skipped++; synced++; continue; }

                    var workOrder = await _db.workOrders
                        .FirstOrDefaultAsync(w => w.InternalWONumber == woNumber);
                    if (workOrder == null) { skipped++; continue; }

                    int? dispatchId = null;
                    if (!string.IsNullOrWhiteSpace(dispatchNumber))
                    {
                        var dispatch = await _db.Dispatches
                            .FirstOrDefaultAsync(d => d.DispatchNumber == dispatchNumber && d.WorkOrderId == workOrder.Id);
                        dispatchId = dispatch?.Id;
                    }

                    var comment = new Comments
                    {
                        ExternalCommentId = replyId,
                        WorkerOrderId = workOrder.Id,
                        DispatchId = dispatchId,
                        Commenttext = GetString(item, "reply_text"),
                        Commenter = GetString(item, "sender_email"),
                        CommentType = "vendor",
                        RecordType = "vendor_reply",
                        CreatedDate = ParseDate(GetString(item, "received_at")) ?? DateTime.UtcNow,
                    };

                    _db.Comments.Add(comment);
                    created++;
                    synced++;

                    if (synced % 50 == 0)
                        await _db.SaveChangesAsync();
                }

                lastKey = response.LastEvaluatedKey;
            } while (lastKey != null && lastKey.Count > 0);

            await _db.SaveChangesAsync();
            return Ok(new { synced, created, skipped });
        }

        [HttpPost("BackfillCommentTypes")]
        public async Task<IActionResult> BackfillCommentTypes()
        {
            if (SyncDisabledResult() is { } disabled)
                return disabled;

            var updated = await _db.Database.ExecuteSqlRawAsync(
                "UPDATE Comments SET CommentType = 'customer' WHERE ExternalCommentId IS NOT NULL AND (CommentType IS NULL OR CommentType = '')");
            return Ok(new { updated });
        }

        [HttpPost("All")]
        public async Task<IActionResult> SyncAll()
        {
            if (SyncDisabledResult() is { } disabled)
                return disabled;

            var woResult = await SyncWorkOrders() as OkObjectResult;
            var commentResult = await SyncComments() as OkObjectResult;

            return Ok(new
            {
                workOrders = woResult?.Value,
                comments = commentResult?.Value
            });
        }

        private async Task<(int? LocationId, bool Created)> ResolveLocationId(string? siteCode, string? building, string? address)
        {
            if (string.IsNullOrWhiteSpace(siteCode) && string.IsNullOrWhiteSpace(building))
                return (null, false);

            var matchCode = siteCode ?? building;
            var existing = await _db.Locations
                .FirstOrDefaultAsync(l => l.Name == matchCode || l.Title == matchCode);

            if (existing != null)
                return (existing.Id, false);

            var location = new Locations
            {
                Name = matchCode,
                Title = building,
                Address1 = address,
                Status = "Active"
            };

            _db.Locations.Add(location);
            await _db.SaveChangesAsync();

            return (location.Id, true);
        }

        private static string? GetString(Dictionary<string, AttributeValue> item, string key)
        {
            if (item.TryGetValue(key, out var val) && val.S != null)
                return val.S;
            return null;
        }

        private static DateTime? ParseDate(string? value)
        {
            if (string.IsNullOrWhiteSpace(value)) return null;
            if (DateTime.TryParse(value, out var dt)) return dt;
            return null;
        }

        private static string? MapStatus(string? dynamoStatus)
        {
            return dynamoStatus switch
            {
                "new" => "Open",
                "assigned" => "Open",
                "in_progress" => "In Progress",
                "on_hold" => "On Hold",
                "completed" => "Done",
                "cancelled" => "Cancelled",
                "unknown" => "Open",
                _ => "Open"
            };
        }

        private static string? MapSeverityToPriority(string? severity)
        {
            if (string.IsNullOrWhiteSpace(severity)) return null;
            return $"Sev {severity}";
        }
    }
}