using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Nop.Plugin.Misc.FruitBankPlugin.Domains.DataLayer;
using Nop.Plugin.Misc.FruitBankPlugin.Services;
using Nop.Services.Catalog;
using Nop.Services.Customers;
using Nop.Services.Security;
using Nop.Web.Framework;
using Nop.Web.Framework.Controllers;
using Nop.Web.Framework.Mvc.Filters;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace Nop.Plugin.Misc.FruitBankPlugin.Areas.Admin.Controllers
{
    [AuthorizeAdmin]
    [Area(AreaNames.ADMIN)]
    [AutoValidateAntiforgeryToken]
    public class VoiceOrderController : BasePluginController
    {
        private readonly IPermissionService _permissionService;
        private readonly OpenAIApiService _aiApiService;
        private readonly ICustomerService _customerService;
        private readonly IProductService _productService;
        private readonly FruitBankDbContext _dbContext;

        public VoiceOrderController(
            IPermissionService permissionService,
            OpenAIApiService aiApiService,
            ICustomerService customerService,
            IProductService productService,
            FruitBankDbContext dbContext)
        {
            _permissionService = permissionService;
            _aiApiService = aiApiService;
            _customerService = customerService;
            _productService = productService;
            _dbContext = dbContext;
        }

        /// <summary>
        /// Display the voice order creation page
        /// </summary>
        [HttpGet]
        public async Task<IActionResult> Create()
        {
            if (!await _permissionService.AuthorizeAsync(StandardPermission.Security.ACCESS_ADMIN_PANEL))
                return AccessDeniedView();

            return View("~/Plugins/Misc.FruitBankPlugin/Areas/Admin/Views/VoiceOrder/Create.cshtml");
        }

        /// <summary>
        /// Transcribe audio for partner name and return matching partners
        /// </summary>
        [HttpPost]
        public async Task<IActionResult> TranscribeForPartner(IFormFile audioFile)
        {
            if (!await _permissionService.AuthorizeAsync(StandardPermission.Security.ACCESS_ADMIN_PANEL))
                return Json(new { success = false, message = "Access denied" });

            if (audioFile == null || audioFile.Length == 0)
            {
                return Json(new { success = false, message = "No audio file received" });
            }

            try
            {
                // Build partner names prompt for Whisper vocabulary hints
                // Whisper has a 224 character limit, so extract unique KEYWORDS instead of full names
                var allCustomers = await _customerService.GetAllCustomersAsync(pageIndex: 0, pageSize: 300);

                var companyNames = allCustomers
                    .Where(c => !string.IsNullOrEmpty(c.Company))
                    .Select(c => c.Company.Trim())
                    .Distinct()
                    .ToList();

                // Extract unique keywords from company names
                var keywords = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
                foreach (var company in companyNames)
                {
                    // Split by common separators and extract meaningful words
                    var words = company.Split(new[] { ' ', ',', '.', '-', '/', '(', ')' }, StringSplitOptions.RemoveEmptyEntries);

                    foreach (var word in words)
                    {
                        var cleaned = word.Trim();

                        // Skip very short words, common abbreviations, and legal terms
                        if (cleaned.Length < 3) continue;
                        if (cleaned.Equals("BV", StringComparison.OrdinalIgnoreCase)) continue;
                        if (cleaned.Equals("Ltd", StringComparison.OrdinalIgnoreCase)) continue;
                        if (cleaned.Equals("Kft", StringComparison.OrdinalIgnoreCase)) continue;
                        if (cleaned.Equals("Inc", StringComparison.OrdinalIgnoreCase)) continue;
                        if (cleaned.Equals("GmbH", StringComparison.OrdinalIgnoreCase)) continue;
                        if (cleaned.Equals("SRL", StringComparison.OrdinalIgnoreCase)) continue;

                        keywords.Add(cleaned);
                    }
                }

                // Build prompt from keywords, fitting as many as possible in 224 chars
                var keywordList = keywords.OrderBy(k => k.Length).ToList();
                var promptParts = new List<string>();
                int currentLength = 0;
                const int maxLength = 220;

                foreach (var keyword in keywordList)
                {
                    var toAdd = promptParts.Count == 0 ? keyword : ", " + keyword;

                    if (currentLength + toAdd.Length > maxLength)
                        break;

                    promptParts.Add(keyword);
                    currentLength += toAdd.Length;
                }

                var partnerPrompt = string.Join(", ", promptParts);
                Console.WriteLine($"[VoiceOrder] Whisper prompt with {promptParts.Count} keywords from {companyNames.Count} partners ({partnerPrompt.Length} chars)");

                // Transcribe audio in HUNGARIAN with partner keywords as vocabulary hints
                var transcribedText = await TranscribeAudioFile(audioFile, "hu", partnerPrompt);

                if (string.IsNullOrEmpty(transcribedText))
                {
                    return Json(new { success = false, message = "Failed to transcribe audio" });
                }

                Console.WriteLine($"[VoiceOrder] Partner transcription (HU): {transcribedText}");

                // Search for matching partners
                var partners = await SearchPartners(transcribedText);

                return Json(new
                {
                    success = true,
                    transcription = transcribedText,
                    partners = partners
                });
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[VoiceOrder] Error in TranscribeForPartner: {ex.Message}");
                return Json(new { success = false, message = $"Error: {ex.Message}" });
            }
        }

        /// <summary>
        /// Transcribe audio for products and parse quantities using AI
        /// </summary>
        [HttpPost]
        public async Task<IActionResult> TranscribeForProducts(IFormFile audioFile)
        {
            if (!await _permissionService.AuthorizeAsync(StandardPermission.Security.ACCESS_ADMIN_PANEL))
                return Json(new { success = false, message = "Access denied" });

            if (audioFile == null || audioFile.Length == 0)
            {
                return Json(new { success = false, message = "No audio file received" });
            }

            try
            {
                // Transcribe audio in HUNGARIAN
                var transcribedText = await TranscribeAudioFile(audioFile, "hu");

                if (string.IsNullOrEmpty(transcribedText))
                {
                    return Json(new { success = false, message = "Failed to transcribe audio" });
                }

                Console.WriteLine($"[VoiceOrder] Product transcription (HU): {transcribedText}");

                // Parse products and quantities using AI
                var parsedProducts = await ParseProductsFromText(transcribedText);

                if (parsedProducts == null || parsedProducts.Count == 0)
                {
                    return Json(new
                    {
                        success = false,
                        message = "Could not parse products from transcription",
                        transcription = transcribedText
                    });
                }

                // Enrich with actual product data from database
                var enrichedProducts = await EnrichProductData(parsedProducts);

                return Json(new
                {
                    success = true,
                    transcription = transcribedText,
                    products = enrichedProducts
                });
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[VoiceOrder] Error in TranscribeForProducts: {ex.Message}");
                return Json(new { success = false, message = $"Error: {ex.Message}" });
            }
        }

        /// <summary>
        /// Search for partners by manually typed text (no audio transcription needed)
        /// </summary>
        [HttpPost]
        public async Task<IActionResult> SearchPartnerByText(string text)
        {
            if (!await _permissionService.AuthorizeAsync(StandardPermission.Security.ACCESS_ADMIN_PANEL))
                return Json(new { success = false, message = "Access denied" });

            if (string.IsNullOrWhiteSpace(text))
            {
                return Json(new { success = false, message = "No text provided" });
            }

            try
            {
                Console.WriteLine($"[VoiceOrder] Manual partner search: {text}");

                // Search for matching partners (same logic as voice)
                var partners = await SearchPartners(text);

                return Json(new
                {
                    success = true,
                    transcription = text,
                    partners = partners
                });
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[VoiceOrder] Error in SearchPartnerByText: {ex.Message}");
                return Json(new { success = false, message = $"Error: {ex.Message}" });
            }
        }

        /// <summary>
        /// Parse manually typed product text (no audio transcription needed)
        /// </summary>
        [HttpPost]
        public async Task<IActionResult> ParseManualProductText(string text)
        {
            if (!await _permissionService.AuthorizeAsync(StandardPermission.Security.ACCESS_ADMIN_PANEL))
                return Json(new { success = false, message = "Access denied" });

            if (string.IsNullOrWhiteSpace(text))
            {
                return Json(new { success = false, message = "No text provided" });
            }

            try
            {
                Console.WriteLine($"[VoiceOrder] Manual product input: {text}");

                // Parse products and quantities using AI (same as voice)
                var parsedProducts = await ParseProductsFromText(text);

                if (parsedProducts == null || parsedProducts.Count == 0)
                {
                    return Json(new
                    {
                        success = false,
                        message = "Could not parse products from text",
                        transcription = text
                    });
                }

                // Enrich with actual product data from database
                var enrichedProducts = await EnrichProductData(parsedProducts);

                return Json(new
                {
                    success = true,
                    transcription = text,
                    products = enrichedProducts
                });
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[VoiceOrder] Error in ParseManualProductText: {ex.Message}");
                return Json(new { success = false, message = $"Error: {ex.Message}" });
            }
        }

        #region Helper Methods

        /// <summary>
        /// Transcribe audio file using OpenAI Whisper
        /// </summary>
        private async Task<string> TranscribeAudioFile(IFormFile audioFile, string language, string customPrompt = null)
        {
            var fileName = $"voice_order_{DateTime.Now:yyyyMMdd_HHmmss}.webm";
            var uploadsFolder = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot", "uploads", "voice");

            if (!Directory.Exists(uploadsFolder))
            {
                Directory.CreateDirectory(uploadsFolder);
            }

            var filePath = Path.Combine(uploadsFolder, fileName);

            // Save file temporarily
            using (var stream = new FileStream(filePath, FileMode.Create))
            {
                await audioFile.CopyToAsync(stream);
            }

            // Transcribe using OpenAI Whisper
            string transcribedText;
            using (var audioStream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
            {
                transcribedText = await _aiApiService.TranscribeAudioAsync(audioStream, fileName, language, customPrompt);
            }

            // Clean up temporary file
            try
            {
                System.IO.File.Delete(filePath);
            }
            catch { /* Ignore cleanup errors */ }

            return transcribedText;
        }

        /// <summary>
        /// Search for partners matching the transcribed text
        /// Uses both string-based and AI semantic search for best results
        /// </summary>
        private async Task<List<object>> SearchPartners(string searchTerm)
        {
            const int maxResults = 10;

            Console.WriteLine($"[VoiceOrder] Searching partners for: {searchTerm}");

            // Step 1: String-based search (fast, catches exact matches)
            var customersByCompany = await _customerService.GetAllCustomersAsync(
                company: searchTerm,
                pageIndex: 0,
                pageSize: maxResults);

            var customersByName = await _customerService.GetAllCustomersAsync(
                firstName: searchTerm,
                pageIndex: 0,
                pageSize: maxResults);

            var customersByLastName = await _customerService.GetAllCustomersAsync(
                lastName: searchTerm,
                pageIndex: 0,
                pageSize: maxResults);

            // Combine string search results
            var stringResults = customersByCompany
                .Union(customersByName)
                .Union(customersByLastName)
                .DistinctBy(c => c.Id)
                .Take(maxResults)
                .ToList();

            Console.WriteLine($"[VoiceOrder] String-based search found {stringResults.Count} partners");

            // Step 2: ALWAYS use AI semantic search for better results
            Console.WriteLine("[VoiceOrder] Using AI semantic matching for partners");
            var aiMatches = await SemanticPartnerSearch(searchTerm);
            Console.WriteLine($"[VoiceOrder] AI semantic search found {aiMatches.Count} partners");

            // Step 3: Merge results - string matches first (exact), then AI matches
            var allCustomers = stringResults
                .Union(aiMatches)
                .DistinctBy(c => c.Id)
                .Take(maxResults)
                .ToList();

            Console.WriteLine($"[VoiceOrder] Total unique partners: {allCustomers.Count}");

            // Format results
            var result = new List<object>();
            foreach (var customer in allCustomers)
            {
                var fullName = await _customerService.GetCustomerFullNameAsync(customer);
                var company = customer.Company;

                if (string.IsNullOrEmpty(fullName))
                    fullName = "[No name]";
                if (string.IsNullOrEmpty(company))
                    company = "[No company]";

                string label = $"{company} ({fullName}), {customer.Email}";

                result.Add(new
                {
                    label = label,
                    value = customer.Id
                });
            }

            return result;
        }

        /// <summary>
        /// Use AI to semantically match partner names based on company name
        /// </summary>
        private async Task<List<Nop.Core.Domain.Customers.Customer>> SemanticPartnerSearch(string searchTerm)
        {
            try
            {
                // Get all customers with company names (increased limit)
                var allCustomersWithCompany = await _customerService.GetAllCustomersAsync(
                    pageIndex: 0,
                    pageSize: 1000); // Increased from 500 to catch more companies

                // Filter to only those with company names
                var customersWithCompany = allCustomersWithCompany
                    .Where(c => !string.IsNullOrEmpty(c.Company))
                    .ToList();

                if (customersWithCompany.Count == 0)
                {
                    Console.WriteLine("[VoiceOrder] No customers with company names found");
                    return new List<Nop.Core.Domain.Customers.Customer>();
                }

                Console.WriteLine($"[VoiceOrder] AI searching through {customersWithCompany.Count} companies");

                // Build company list for AI
                var companyList = string.Join("\n", customersWithCompany
                    .Select((c, index) => $"{index}|{c.Company}"));

                var systemPrompt = @"You are a company name matcher for a B2B system.
Given a spoken company name and a list of company names, find the 5 best matches.

CRITICAL MATCHING RULES (in priority order):
1. EXACT MATCH: If the search term appears exactly in a company name, prioritize it
2. SUBSTRING MATCH: If the search term is contained within a company name (e.g., 'Junket' in 'Junket Silver Kft.')
3. WORD MATCH: If all words from search term appear in company name (any order)
4. PARTIAL MATCH: If significant words overlap (e.g., 'Silver' matches 'Junket Silver')
5. PHONETIC SIMILARITY: How it sounds when spoken
6. ABBREVIATIONS: 'SFI' matches 'SFI Rotterdam B.V.'

EXAMPLES:
Search: 'Junket Silver'
Should match: 'Junket Silver Kft.' (substring match - VERY HIGH PRIORITY)

Search: 'Rotterdam'
Should match: 'SFI Rotterdam B.V.' (substring match)

Return ONLY a JSON array with the top 5 indices, ordered by best match first.
If fewer than 5 matches exist, return fewer indices.

OUTPUT FORMAT (JSON only):
[0, 15, 42, 103, 256]";

                var userPrompt = $@"Search term: {searchTerm}
Companies:
{companyList}";

                var aiResponse = await _aiApiService.GetSimpleResponseAsync(systemPrompt, userPrompt);

                Console.WriteLine($"[VoiceOrder] AI company matching response: {aiResponse}");

                // Extract JSON array from response
                var jsonMatch = Regex.Match(aiResponse, @"\[[\d,\s]*\]", RegexOptions.Singleline);
                if (!jsonMatch.Success)
                {
                    Console.WriteLine("[VoiceOrder] No JSON array found in AI response");
                    return new List<Nop.Core.Domain.Customers.Customer>();
                }

                var jsonText = jsonMatch.Value;
                var indices = System.Text.Json.JsonSerializer.Deserialize<List<int>>(jsonText);

                if (indices == null || indices.Count == 0)
                {
                    Console.WriteLine("[VoiceOrder] AI returned no matches");
                    return new List<Nop.Core.Domain.Customers.Customer>();
                }

                // Get customers by indices
                var matchedCustomers = indices
                    .Where(i => i >= 0 && i < customersWithCompany.Count)
                    .Select(i => customersWithCompany[i])
                    .ToList();

                Console.WriteLine($"[VoiceOrder] AI matched {matchedCustomers.Count} companies: {string.Join(", ", matchedCustomers.Select(c => c.Company))}");

                return matchedCustomers;
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[VoiceOrder] Error in semantic partner search: {ex.Message}");
                return new List<Nop.Core.Domain.Customers.Customer>();
            }
        }

        /// <summary>
        /// Parse products and quantities from transcribed text using AI
        /// </summary>
        private async Task<List<ParsedProduct>> ParseProductsFromText(string text)
        {
            var systemPrompt = @"You are a product parser for a Hungarian fruit and vegetable wholesale company.
Parse the product names and quantities from the user's speech.

CRITICAL RULES:
1. Extract product names and quantities from ANY produce item (fruits, vegetables, herbs, etc.)
2. Normalize product names to singular, lowercase (e.g., 'narancsok' → 'narancs', 'áfonyák' → 'áfonya')
3. Handle Hungarian number words ('száz' = 100, 'ötven' = 50, 'húsz' = 20, 'tíz' = 10, 'öt' = 5, 'egy' = 1, etc.)
4. FIX COMMON TRANSCRIPTION ERRORS:
   - 'datója' → 'datolya' (dates)
   - 'szűlő' → 'szőlő' (grapes)
   - 'mondarin' → 'mandarin' (mandarin)
   - 'paprika' is correct (pepper/paprika)
   - 'fokhagyma' is correct (garlic)
   - Any obvious typo → correct it
5. Return ONLY valid JSON array, no explanations or empty arrays
6. DO NOT include units - only product name and quantity as a number
7. ALWAYS return at least one product if you can parse anything from the input

OUTPUT FORMAT (JSON only):
[
  {""product"": ""narancs"", ""quantity"": 100},
  {""product"": ""alma"", ""quantity"": 50}
]

EXAMPLES:
Input: 'narancs száz kilogram és alma ötven kiló'
Output: [{""product"":""narancs"",""quantity"":100},{""product"":""alma"",""quantity"":50}]

Input: 'fokhagyma, 1'
Output: [{""product"":""fokhagyma"",""quantity"":1}]

Input: 'paprika, öt rekesz'
Output: [{""product"":""paprika"",""quantity"":5}]

Input: 'mondarin öt rekesz' (typo in 'mandarin')
Output: [{""product"":""mandarin"",""quantity"":5}]

Input: 'menta, 1'
Output: [{""product"":""menta"",""quantity"":1}]

Input: 'datója tíz láda' (WRONG transcription)
Output: [{""product"":""datolya"",""quantity"":10}]

Input: 'szűlő ötven kiló' (WRONG transcription)
Output: [{""product"":""szőlő"",""quantity"":50}]";

            var userPrompt = $"Parse this: {text}";

            var aiResponse = await _aiApiService.GetSimpleResponseAsync(systemPrompt, userPrompt);

            Console.WriteLine($"[VoiceOrder] AI Response: {aiResponse}");

            // Try to extract JSON from response
            var jsonMatch = Regex.Match(aiResponse, @"\[.*\]", RegexOptions.Singleline);
            if (!jsonMatch.Success)
            {
                Console.WriteLine("[VoiceOrder] No JSON array found in AI response");
                return new List<ParsedProduct>();
            }

            var jsonText = jsonMatch.Value;

            try
            {
                var parsedProducts = System.Text.Json.JsonSerializer.Deserialize<List<ParsedProduct>>(jsonText);
                return parsedProducts ?? new List<ParsedProduct>();
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[VoiceOrder] Error parsing JSON: {ex.Message}");
                return new List<ParsedProduct>();
            }
        }

        /// <summary>
        /// Enrich parsed products with actual product data from database
        /// Returns ALL matching products so admin can select the exact one
        /// </summary>
        private async Task<List<object>> EnrichProductData(List<ParsedProduct> parsedProducts)
        {
            var enrichedProducts = new List<object>();

            // OPTIMIZATION: Load all ProductDtos once instead of querying one by one
            var helperProductDtos = await _dbContext.ProductDtos.GetAll(true).ToListAsync();

            foreach (var parsed in parsedProducts)
            {
                // Search for ALL matching products in database
                var products = await _productService.SearchProductsAsync(
                    keywords: parsed.Product,
                    pageIndex: 0,
                    pageSize: 50); // Get up to 20 matches

                if (!products.Any())
                {
                    Console.WriteLine($"[VoiceOrder] No product found for: {parsed.Product}");
                    continue;
                }

                Console.WriteLine($"[VoiceOrder] Found {products.Count()} products matching '{parsed.Product}'");

                // Add ALL matching products for admin to choose from
                foreach (var product in products)
                {
                    var productDto = helperProductDtos.FirstOrDefault(x => x.Id == product.Id);

                    if (productDto == null)
                    {
                        Console.WriteLine($"[VoiceOrder] ProductDto not found for product ID: {product.Id}");
                        continue;
                    }

                    // Check if enough stock
                    var availableQuantity = product.StockQuantity + productDto.IncomingQuantity;
                    if (availableQuantity <= 0)
                    {
                        Console.WriteLine($"[VoiceOrder] Product {product.Name} has no stock - skipping");
                        continue;
                    }

                    // Validate requested quantity against available stock
                    var requestedQuantity = parsed.Quantity;
                    var finalQuantity = requestedQuantity;
                    var isQuantityReduced = false;

                    if (requestedQuantity > availableQuantity)
                    {
                        Console.WriteLine($"[VoiceOrder] WARNING: Product {product.Name} - Requested {requestedQuantity} but only {availableQuantity} available. Capping to available.");
                        finalQuantity = availableQuantity;
                        isQuantityReduced = true;
                    }

                    // Add to enriched list with validated quantity
                    enrichedProducts.Add(new
                    {
                        id = product.Id,
                        name = product.Name,
                        sku = product.Sku,
                        quantity = finalQuantity, // Use validated quantity (capped to available)
                        requestedQuantity = requestedQuantity, // Original requested amount
                        price = product.Price,
                        stockQuantity = availableQuantity,
                        searchTerm = parsed.Product, // Track what was searched for
                        isQuantityReduced = isQuantityReduced // Flag if we had to reduce
                    });
                }
            }

            Console.WriteLine($"[VoiceOrder] Total enriched products to display: {enrichedProducts.Count}");
            return enrichedProducts;
        }

        #endregion

        #region Models

        private class ParsedProduct
        {
            [System.Text.Json.Serialization.JsonPropertyName("product")]
            public string Product { get; set; }

            [System.Text.Json.Serialization.JsonPropertyName("quantity")]
            public int Quantity { get; set; }
        }

        #endregion
    }
}