package web

import (
	"bytes"
	"encoding/csv"
	"fmt"
	"io"
	"log"
	"mime/multipart"
	"net/http"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"

	root "marmic/servicetrade-toolbox"
	"marmic/servicetrade-toolbox/internal/api"
)

// DocumentsHandler handles the document upload page
func DocumentsHandler(w http.ResponseWriter, r *http.Request) {
	session, ok := r.Context().Value("session").(*api.Session)
	if !ok {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	tmpl := root.WebTemplates
	data := map[string]interface{}{
		"Title":   "Document Uploads",
		"Session": session,
	}

	if r.Header.Get("HX-Request") == "true" {
		// For HTMX requests, just send the document_upload partial
		if err := tmpl.ExecuteTemplate(w, "document_upload", data); err != nil {
			log.Printf("Template execution error: %v", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}
	} else {
		// For full page requests, first render document_upload into a buffer
		var contentBuf bytes.Buffer
		if err := tmpl.ExecuteTemplate(&contentBuf, "document_upload", data); err != nil {
			log.Printf("Template execution error: %v", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}

		// Add the rendered content to the data for the layout
		data["BodyContent"] = contentBuf.String()

		// Now render the layout with our content
		if err := tmpl.ExecuteTemplate(w, "layout.html", data); err != nil {
			log.Printf("Template execution error: %v", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}
	}
}

// ProcessCSVHandler processes a CSV file with job numbers
func ProcessCSVHandler(w http.ResponseWriter, r *http.Request) {
	_, ok := r.Context().Value("session").(*api.Session)
	if !ok {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	// Check if the request method is POST
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// Parse the multipart form data with a 10MB limit
	if err := r.ParseMultipartForm(10 << 20); err != nil {
		http.Error(w, "Unable to parse form: "+err.Error(), http.StatusBadRequest)
		return
	}

	// Get the file from the form
	file, _, err := r.FormFile("csvFile")
	if err != nil {
		http.Error(w, "Error retrieving file: "+err.Error(), http.StatusBadRequest)
		return
	}
	defer file.Close()

	// Read the CSV data
	csvData, err := csv.NewReader(file).ReadAll()
	if err != nil {
		http.Error(w, "Error reading CSV file: "+err.Error(), http.StatusBadRequest)
		return
	}

	if len(csvData) < 2 {
		http.Error(w, "CSV file must contain at least a header row and one data row", http.StatusBadRequest)
		return
	}

	// Find the index of the 'id' column
	headerRow := csvData[0]
	idColumnIndex := -1
	for i, header := range headerRow {
		if strings.ToLower(strings.TrimSpace(header)) == "id" {
			idColumnIndex = i
			break
		}
	}

	// If 'id' column not found, try the first column
	if idColumnIndex == -1 {
		idColumnIndex = 0
		log.Printf("No 'id' column found in CSV, using first column (header: %s)", headerRow[0])
	} else {
		log.Printf("Found 'id' column at index %d", idColumnIndex)
	}

	// Extract job numbers from the CSV
	var jobNumbers []string
	for rowIndex, row := range csvData {
		// Skip header row
		if rowIndex == 0 {
			continue
		}

		if len(row) > idColumnIndex {
			// Extract and clean up the job ID
			jobID := strings.TrimSpace(row[idColumnIndex])
			if jobID != "" {
				jobNumbers = append(jobNumbers, jobID)
			}
		}
	}

	totalJobs := len(jobNumbers)
	log.Printf("Extracted %d job IDs from CSV", totalJobs)

	if totalJobs == 0 {
		http.Error(w, "No valid job IDs found in the CSV file", http.StatusBadRequest)
		return
	}

	// Create a hidden input with the job IDs
	jobsValue := strings.Join(jobNumbers, ",")
	jobSampleDisplay := getJobSampleDisplay(jobNumbers)

	// Generate HTML for the main response (hidden input for job-ids-container)
	var responseHTML bytes.Buffer
	responseHTML.WriteString(fmt.Sprintf(`<input type="hidden" name="jobNumbers" value="%s">`, jobsValue))
	responseHTML.WriteString(fmt.Sprintf(`<p>Found <strong>%d</strong> job(s) in the CSV file</p>`, totalJobs))
	responseHTML.WriteString(fmt.Sprintf(`<div class="csv-sample"><p>Sample job IDs: %s</p></div>`, jobSampleDisplay))

	// Generate out-of-band swap for the preview section
	responseHTML.WriteString(fmt.Sprintf(`
		<div id="csv-preview" class="fade-me-out" style="display: block !important; margin-top: 1rem;" hx-swap-oob="true">
			<h4>Detected Jobs</h4>
			<div id="csv-preview-content" class="job-list">
				<p>Found <strong>%d</strong> job(s) in the CSV file</p>
				<div class="csv-sample">
					<p>Sample job IDs: %s</p>
				</div>
			</div>
		</div>
	`, totalJobs, jobSampleDisplay))

	w.Header().Set("Content-Type", "text/html")
	w.Write(responseHTML.Bytes())
}

// Helper function to show sample job IDs with a limit
func getJobSampleDisplay(jobIDs []string) string {
	const maxSamples = 5
	if len(jobIDs) <= maxSamples {
		return strings.Join(jobIDs, ", ")
	}

	sample := append([]string{}, jobIDs[:maxSamples]...)
	return strings.Join(sample, ", ") + fmt.Sprintf(" and %d more...", len(jobIDs)-maxSamples)
}

// UploadDocumentsHandler handles document uploads to jobs
func UploadDocumentsHandler(w http.ResponseWriter, r *http.Request) {
	session, ok := r.Context().Value("session").(*api.Session)
	if !ok {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	// Check if the request method is POST
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// Parse the multipart form with a 30MB limit
	if err := r.ParseMultipartForm(30 << 20); err != nil {
		http.Error(w, fmt.Sprintf("Unable to parse form: %v", err), http.StatusBadRequest)
		return
	}

	// Get the job numbers from either of the possible form fields
	jobNumbers := r.FormValue("jobNumbers")
	if jobNumbers == "" {
		jobNumbers = r.FormValue("job-ids")
		if jobNumbers == "" {
			log.Printf("No job numbers provided. Form data: %+v", r.Form)
			http.Error(w, "No job numbers provided", http.StatusBadRequest)
			return
		}
	}

	// Log the form data for debugging
	log.Printf("Form data: %+v", r.Form)
	log.Printf("Job numbers: %s", jobNumbers)

	// Split the job numbers
	jobs := strings.Split(jobNumbers, ",")
	if len(jobs) == 0 {
		http.Error(w, "No valid job numbers provided", http.StatusBadRequest)
		return
	}

	// Regular expression to match file field patterns
	filePattern := regexp.MustCompile(`document-file-(\d+)`)

	// Collect document data
	type DocumentData struct {
		File   multipart.File
		Header *multipart.FileHeader
		Name   string
		Type   string
		Index  int
	}

	var documents []DocumentData

	// First, identify all available indices
	var indices []int
	for key := range r.MultipartForm.File {
		if matches := filePattern.FindStringSubmatch(key); len(matches) > 1 {
			if index, err := strconv.Atoi(matches[1]); err == nil {
				indices = append(indices, index)
			}
		}
	}

	// Process each document
	for _, index := range indices {
		fileKey := fmt.Sprintf("document-file-%d", index)
		nameKey := fmt.Sprintf("document-name-%d", index)
		typeKey := fmt.Sprintf("document-type-%d", index)

		fileHeaders := r.MultipartForm.File[fileKey]
		if len(fileHeaders) == 0 {
			continue // Skip if no file uploaded
		}

		fileHeader := fileHeaders[0]
		file, err := fileHeader.Open()
		if err != nil {
			log.Printf("Error opening file %s: %v", fileHeader.Filename, err)
			continue
		}

		// Get document name (use filename if not provided)
		documentName := r.FormValue(nameKey)
		if documentName == "" {
			documentName = fileHeader.Filename
		} else {
			// If a custom name is provided without extension, add the original file extension
			if !strings.Contains(documentName, ".") {
				extension := filepath.Ext(fileHeader.Filename)
				if extension != "" {
					documentName = documentName + extension
				}
			}
		}

		log.Printf("Using document name: %s (original filename: %s)", documentName, fileHeader.Filename)

		// Get document type
		documentType := r.FormValue(typeKey)
		if documentType == "" {
			log.Printf("No document type for file %s", fileHeader.Filename)
			continue
		}

		// Log the document type for debugging
		log.Printf("Document type for %s: '%s'", documentName, documentType)

		documents = append(documents, DocumentData{
			File:   file,
			Header: fileHeader,
			Name:   documentName,
			Type:   documentType,
			Index:  index,
		})
	}

	if len(documents) == 0 {
		http.Error(w, "No valid documents selected for upload", http.StatusBadRequest)
		return
	}

	// Read all file contents first to avoid keeping files open during concurrent uploads
	type DocumentWithContent struct {
		Name        string
		Type        string
		FileContent []byte
	}

	var docsWithContent []DocumentWithContent
	for _, doc := range documents {
		// Read file content
		fileContent, err := io.ReadAll(doc.File)
		if err != nil {
			log.Printf("Error reading file %s: %v", doc.Header.Filename, err)
			continue
		}
		doc.File.Close() // Close the file as soon as we're done with it

		docsWithContent = append(docsWithContent, DocumentWithContent{
			Name:        doc.Name,
			Type:        doc.Type,
			FileContent: fileContent,
		})
	}

	// Concurrent upload with throttling
	// ServiceTrade API allows 30s of availability per minute (approximately 15 requests at 2s each)
	const maxConcurrent = 5                     // A conservative limit to avoid rate limiting
	const requestDelay = 300 * time.Millisecond // Delay between requests

	// Channel for collecting results
	type UploadResult struct {
		JobID   string
		DocName string
		Success bool
		Error   string
		Data    map[string]interface{}
	}

	totalUploads := len(jobs) * len(docsWithContent)
	resultsChan := make(chan UploadResult, totalUploads)

	// Create a wait group to track when all uploads are done
	var wg sync.WaitGroup

	// Create a semaphore channel to limit concurrent uploads
	semaphore := make(chan struct{}, maxConcurrent)

	// Start the upload workers
	for _, jobID := range jobs {
		for _, doc := range docsWithContent {
			wg.Add(1)

			// Launch a goroutine for each job+document combination
			go func(jobID string, doc DocumentWithContent) {
				defer wg.Done()

				// Acquire a semaphore slot
				semaphore <- struct{}{}
				defer func() { <-semaphore }() // Release when done

				// Add a small delay to avoid overwhelming the API
				time.Sleep(requestDelay)

				// Call the ServiceTrade API
				result, err := session.UploadAttachment(jobID, doc.Name, doc.Type, doc.FileContent)

				if err != nil {
					log.Printf("Error uploading %s to job %s: %v", doc.Name, jobID, err)
					resultsChan <- UploadResult{
						JobID:   jobID,
						DocName: doc.Name,
						Success: false,
						Error:   err.Error(),
					}
				} else {
					log.Printf("Successfully uploaded %s to job %s", doc.Name, jobID)
					resultsChan <- UploadResult{
						JobID:   jobID,
						DocName: doc.Name,
						Success: true,
						Data:    result,
					}
				}
			}(jobID, doc)
		}
	}

	// Close the results channel when all uploads are done
	go func() {
		wg.Wait()
		close(resultsChan)
	}()

	// Collect results
	results := make(map[string][]UploadResult)
	for result := range resultsChan {
		if _, exists := results[result.JobID]; !exists {
			results[result.JobID] = []UploadResult{}
		}
		results[result.JobID] = append(results[result.JobID], result)
	}

	// Generate HTML for results
	var resultHTML bytes.Buffer

	// Count successes and failures
	var totalSuccess, totalFailure int
	for _, jobResults := range results {
		for _, result := range jobResults {
			if result.Success {
				totalSuccess++
			} else {
				totalFailure++
			}
		}
	}

	// Add summary section
	resultHTML.WriteString("<div class=\"upload-summary\">")
	resultHTML.WriteString("<h3>Upload Results</h3>")
	resultHTML.WriteString("<div class=\"upload-stats\">")

	// Total jobs stat
	resultHTML.WriteString("<div class=\"stat-box\">")
	resultHTML.WriteString(fmt.Sprintf("<div class=\"stat-value\">%d</div>", len(results)))
	resultHTML.WriteString("<div class=\"stat-label\">Total Jobs</div>")
	resultHTML.WriteString("</div>")

	// Success stat
	resultHTML.WriteString("<div class=\"stat-box success-stat\">")
	resultHTML.WriteString(fmt.Sprintf("<div class=\"stat-value\">%d</div>", totalSuccess))
	resultHTML.WriteString("<div class=\"stat-label\">Successful Uploads</div>")
	resultHTML.WriteString("</div>")

	// Failure stat
	resultHTML.WriteString("<div class=\"stat-box error-stat\">")
	resultHTML.WriteString(fmt.Sprintf("<div class=\"stat-value\">%d</div>", totalFailure))
	resultHTML.WriteString("<div class=\"stat-label\">Failed Uploads</div>")
	resultHTML.WriteString("</div>")

	// File count stat
	resultHTML.WriteString("<div class=\"stat-box\">")
	resultHTML.WriteString(fmt.Sprintf("<div class=\"stat-value\">%d</div>", totalSuccess+totalFailure))
	resultHTML.WriteString("<div class=\"stat-label\">Files Processed</div>")
	resultHTML.WriteString("</div>")

	resultHTML.WriteString("</div>") // End of upload-stats

	// Add completion message
	if totalFailure == 0 {
		resultHTML.WriteString("<p>All documents were successfully uploaded to ServiceTrade!</p>")
	} else {
		resultHTML.WriteString("<p>Some documents failed to upload. See details below.</p>")
	}

	resultHTML.WriteString("</div>") // End of upload-summary

	// Add detailed job results
	resultHTML.WriteString("<div class=\"job-results\">")

	// Sort job IDs for consistent display
	sortedJobs := make([]string, 0, len(results))
	for jobID := range results {
		sortedJobs = append(sortedJobs, jobID)
	}
	sort.Strings(sortedJobs)

	for _, jobID := range sortedJobs {
		jobResults := results[jobID]

		// Determine job success status
		jobSuccess := true
		for _, result := range jobResults {
			if !result.Success {
				jobSuccess = false
				break
			}
		}

		// Job result row
		jobClass := "success"
		if !jobSuccess {
			jobClass = "error"
		}

		resultHTML.WriteString(fmt.Sprintf("<div class=\"job-result %s\">", jobClass))
		resultHTML.WriteString(fmt.Sprintf("<span class=\"job-id\">Job #%s</span>", jobID))

		// File results
		if len(jobResults) > 0 {
			resultHTML.WriteString("<div class=\"file-results\">")

			for _, result := range jobResults {
				fileClass := "success"
				icon := "✓"
				message := "Successfully uploaded"

				if !result.Success {
					fileClass = "error"
					icon = "✗"
					message = result.Error
				}

				resultHTML.WriteString(fmt.Sprintf("<div class=\"file-result %s\">", fileClass))
				resultHTML.WriteString(fmt.Sprintf("<span class=\"status-icon\">%s</span>", icon))
				resultHTML.WriteString(fmt.Sprintf("<span class=\"file-name\">%s:</span>", result.DocName))
				resultHTML.WriteString(fmt.Sprintf("<span class=\"file-message\">%s</span>", message))
				resultHTML.WriteString("</div>")
			}

			resultHTML.WriteString("</div>") // End of file-results
		} else {
			resultHTML.WriteString("<p>No files processed for this job.</p>")
		}

		resultHTML.WriteString("</div>") // End of job-result
	}

	resultHTML.WriteString("</div>") // End of job-results

	w.Header().Set("Content-Type", "text/html")
	w.Write(resultHTML.Bytes())
}

// DocumentFieldAddHandler generates a new document field for the form
func DocumentFieldAddHandler(w http.ResponseWriter, r *http.Request) {
	// Generate a random ID for the new field
	newId := fmt.Sprintf("%d", time.Now().UnixNano())

	// Create HTML for a new document row
	html := fmt.Sprintf(`
		<div class="document-row" id="document-row-%s">
			<div class="document-field">
				<label>Select Document:</label>
				<input class="card-input" type="file" id="document-file-%s" name="document-file-%s">
			</div>

			<div class="document-field-row">
				<div class="document-field document-name-field">
					<label>Document Name (optional):</label>
					<input class="card-input" type="text" id="document-name-%s" name="document-name-%s"
						placeholder="Document Name">
				</div>

				<div class="document-field document-type-field">
					<label>Document Type:</label>
					<select class="card-input" id="document-type-%s" name="document-type-%s">
						<option value="">Select Document Type</option>
						<option value="1" selected>Job Paperwork</option>
						<option value="2">Job Vendor Bill</option>
						<option value="7">Generic Attachment</option>
						<option value="10">Blank Paperwork</option>
						<option value="14">Job Invoice</option>
					</select>
				</div>
			</div>

			<button type="button" class="remove-document warning-button"
					hx-get="/document-field-remove?id=%s" 
					hx-target="#document-row-%s"
					hx-swap="outerHTML">Remove</button>
		</div>
	`, newId, newId, newId, newId, newId, newId, newId, newId, newId)

	w.Header().Set("Content-Type", "text/html")
	w.Write([]byte(html))
}

// DocumentFieldRemoveHandler handles the removal of a document field
func DocumentFieldRemoveHandler(w http.ResponseWriter, r *http.Request) {
	// We read the ID but don't need to use it for simple removal
	_ = r.URL.Query().Get("id")

	// Count how many document rows exist
	// For simplicity, we'll just return an empty response to remove the field
	// In a complete implementation, we'd check if this is the last field and handle that case

	w.Header().Set("Content-Type", "text/html")
	w.Write([]byte(""))
}