using CPRNIMS.Infrastructure.Dto.Canvass.Response;
using CPRNIMS.Infrastructure.Dto.Canvass.Result;
using Microsoft.Extensions.Configuration;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.Json;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace CPRNIMS.Domain.Services.Canvass
{
    public class SupplierSearchService
    {
        private readonly HttpClient _httpClient;
        private readonly IConfiguration _config;

        // Common contact page suffixes to try
        private static readonly string[] ContactPaths =
            { "/contact", "/contact-us", "/pages/contact-us", "/about/contact", "/about" };

        public SupplierSearchService(HttpClient httpClient, IConfiguration config)
        {
            _httpClient = httpClient;
            _config = config;
        }

        public async Task<List<SupplierResponse>> SearchAndFilterSuppliersAsync(
            string itemName, string itemDescription)
        {
            // Step 1: Tavily — get supplier URLs
            var (searchContent, supplierUrls) = await SearchTavilyAsync(itemName, itemDescription);

            // Step 2: Fetch contact pages from discovered URLs
            var contactContent = await FetchContactPagesAsync(supplierUrls);

            // Step 3: Combine search + contact content, send to Groq
            var combined = searchContent + " CONTACT_PAGES_DATA: " + contactContent;
            var suppliers = await FilterWithGroqAsync(itemName, itemDescription, combined);

            return suppliers;
        }

        // ── Tavily ──────────────────────────────────────────────────────────────
        private async Task<(string content, List<string> urls)> SearchTavilyAsync(
            string itemName, string itemDescription)
        {
            var query = $"{itemName} {itemDescription} suppliers Philippines budget price contact email phone";

            var payload = new
            {
                query,
                max_results = 10,
                search_depth = "advanced",
                include_answer = false
            };

            var request = new HttpRequestMessage(HttpMethod.Post, _config["Tavily:SearchUrl"]);
            request.Headers.Add("Authorization", $"Bearer {_config["Tavily:ApiKey"]}");
            request.Content = new StringContent(
                JsonSerializer.Serialize(payload), Encoding.UTF8, "application/json");

            var response = await _httpClient.SendAsync(request);
            response.EnsureSuccessStatusCode();

            var body = await response.Content.ReadAsStringAsync();
            var result = JsonSerializer.Deserialize<TavilySearchResult>(body,
                new JsonSerializerOptions { PropertyNameCaseInsensitive = true });

            var sb = new StringBuilder();
            var urls = new List<string>();
            int i = 1;

            foreach (var r in result?.Results ?? new())
            {
                // Clean text
                var clean = Regex.Replace(r.Content ?? "", @"[^\x20-\x7E]", " ");
                clean = Regex.Replace(clean, @"\s{3,}", "  ");
                if (clean.Length > 300) clean = clean[..300];
                sb.Append($"{i}. Title:{r.Title}|URL:{r.Url}|Content:{clean}|");

                // Collect base domain URLs for contact page fetching
                try
                {
                    var uri = new Uri(r.Url);
                    var baseUrl = $"{uri.Scheme}://{uri.Host}";
                    if (!urls.Contains(baseUrl)) urls.Add(baseUrl);
                }
                catch { }
                i++;
            }

            var fullText = sb.ToString();
            if (fullText.Length > 2000) fullText = fullText[..2000];

            return (fullText, urls);
        }

        // ── Fetch Contact Pages ──────────────────────────────────────────────────
        private async Task<string> FetchContactPagesAsync(List<string> baseUrls)
        {
            var sb = new StringBuilder();
            // Limit to top 5 domains to avoid timeout
            foreach (var baseUrl in baseUrls.Take(5))
            {
                foreach (var path in ContactPaths)
                {
                    try
                    {
                        var url = baseUrl + path;
                        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(5));
                        var resp = await _httpClient.GetAsync(url, cts.Token);

                        if (!resp.IsSuccessStatusCode) continue;

                        var html = await resp.Content.ReadAsStringAsync();

                        // Strip HTML tags
                        var text = Regex.Replace(html, @"<[^>]+>", " ");
                        text = Regex.Replace(text, @"[^\x20-\x7E]", " ");
                        text = Regex.Replace(text, @"\s{3,}", " ");

                        // Extract only lines with contact signals
                        var contactLines = text.Split(' ', StringSplitOptions.RemoveEmptyEntries)
                            .Where(w => w.Contains("@")
                                     || Regex.IsMatch(w, @"\+?[\d\-\(\)]{7,}")
                                     || w.Contains("email")
                                     || w.Contains("phone")
                                     || w.Contains("contact")
                                     || w.Contains("mobile")
                                     || w.Contains("tel"))
                            .Take(50);

                        var contactText = string.Join(" ", contactLines);
                        if (!string.IsNullOrWhiteSpace(contactText))
                        {
                            sb.Append($"[{baseUrl}]: {contactText} | ");
                            break; // Found contact page for this domain, move to next
                        }
                    }
                    catch { /* timeout or unreachable — skip */ }
                }
            }

            return sb.Length > 2000 ? sb.ToString()[..2000] : sb.ToString();
        }

        // ── Groq ─────────────────────────────────────────────────────────────────
        private async Task<List<SupplierResponse>> FilterWithGroqAsync(
            string itemName, string itemDescription, string searchContent)
        {
            var prompt = $"Extract top 10 unique suppliers for: {itemName} {itemDescription}. " +
                         "Prioritize Philippines suppliers first. " +
                         "IMPORTANT: Look carefully in CONTACT_PAGES_DATA section for real phone numbers and emails. " +
                         "Extract exact email addresses and phone numbers found. " +
                         "For domains without contact data found, infer email as sales@domain or info@domain. " +
                         "Prefer budget-friendly suppliers. No duplicates. " +
                         "Return ONLY a raw JSON array: company_name, country, phone_number, contact_email, website, estimated_price_usd, item_specifications. " +
                         $"Null for missing. JSON array only. Data: {searchContent}";

            var payload = new
            {
                model = _config["Groq:Model"] ?? "llama-3.1-8b-instant",
                stream = false,
                max_tokens = 2048,
                temperature = 0.1,
                messages = new[]
                {
                new { role = "system", content = "You are a supplier data extractor. Extract real contact details from provided content. Return ONLY a valid JSON array, no markdown, no explanation." },
                new { role = "user", content = prompt }
            }
            };

            var request = new HttpRequestMessage(HttpMethod.Post, _config["Groq:ApiUrl"]);
            request.Headers.Add("Authorization", $"Bearer {_config["Groq:ApiKey"]}");
            request.Content = new StringContent(
                JsonSerializer.Serialize(payload), Encoding.UTF8, "application/json");

            var response = await _httpClient.SendAsync(request);
            response.EnsureSuccessStatusCode();

            var body = await response.Content.ReadAsStringAsync();
            var groqResp = JsonSerializer.Deserialize<GroqResponse>(body,
                new JsonSerializerOptions { PropertyNameCaseInsensitive = true });

            var rawText = groqResp?.Choices?[0]?.Message?.Content ?? string.Empty;

            var match = Regex.Match(rawText, @"\[[\s\S]*\]");
            if (!match.Success) return new List<SupplierResponse>();

            var groqList = JsonSerializer.Deserialize<List<GroqSupplierResult>>(match.Value,
                new JsonSerializerOptions { PropertyNameCaseInsensitive = true })
                ?? new List<GroqSupplierResult>();

            var seen = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
            var suppliers = new List<SupplierResponse>();

            foreach (var s in groqList)
            {
                var key = (s.CompanyName ?? "").Trim().ToLower();
                if (string.IsNullOrEmpty(key) || seen.Contains(key)) continue;
                seen.Add(key);

                if (string.IsNullOrEmpty(s.ContactEmail)) continue;

                suppliers.Add(new SupplierResponse
                {
                    SupplierName = s.CompanyName,
                    EmailAddress = s.ContactEmail,
                    ContactNo = s.PhoneNumber ?? string.Empty,
                    Address = s.Country ?? string.Empty,
                    IsActive = true,
                    VatInc = false,
                    Currency = "PHP",
                    CurrencyId = 1,
                    PaymentTermsId = 1,
                    PaymentTerms = "30 Days",
                    LeadTime = "7-14 Days",
                    TinNo = string.Empty,
                    ContactPerson = string.Empty,
                    Website =s.Website ?? string.Empty,
                });

                if (suppliers.Count >= 10) break;
            }

            return suppliers;
        }
    }
}