package handlers

import (
	"bytes"
	"log"
	"net/http"
	"path/filepath"
	"regexp"
	"strings"
	"text/template"
)

// ==============================================================================
// PLAIN TEXT HANDLER
// Renders CV as clean plain text for terminal/AI consumption
// ==============================================================================

// PlainText renders the CV as plain text
// Useful for: curl users, AI crawlers, accessibility, copy-paste
func (h *CVHandler) PlainText(w http.ResponseWriter, r *http.Request) {
	// Get language from query parameter, default to English
	langCode := r.URL.Query().Get("lang")
	if langCode == "" {
		langCode = "en"
	}

	// Validate language
	if langCode != "en" && langCode != "es" {
		http.Error(w, "Unsupported language. Use 'en' or 'es'", http.StatusBadRequest)
		return
	}

	// Prepare template data using shared helper (loads CV data)
	data, err := h.prepareTemplateData(langCode)
	if err != nil {
		log.Printf("PlainText: Failed to load CV data: %v", err)
		http.Error(w, "Failed to load CV data", http.StatusInternalServerError)
		return
	}

	// Add base URL for footer
	data["BaseURL"] = h.serverAddr

	// Load and parse the plain text template
	tmplPath := filepath.Join("templates", "cv-text.txt")
	tmpl, err := template.New("cv-text.txt").ParseFiles(tmplPath)
	if err != nil {
		log.Printf("PlainText: Failed to load template: %v", err)
		http.Error(w, "Failed to load template", http.StatusInternalServerError)
		return
	}

	// Render to buffer
	var buf bytes.Buffer
	if err := tmpl.Execute(&buf, data); err != nil {
		log.Printf("PlainText: Failed to execute template: %v", err)
		http.Error(w, "Failed to render template: "+err.Error(), http.StatusInternalServerError)
		return
	}

	// Clean up the output
	text := cleanPlainText(buf.String())

	// Set response headers
	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
	w.Header().Set("X-Content-Type-Options", "nosniff")

	// Write plain text response
	_, _ = w.Write([]byte(text))
}

// cleanPlainText removes extra whitespace, HTML tags, and wraps long lines
func cleanPlainText(text string) string {
	const maxLineLength = 80

	// Remove HTML tags (from safeHTML fields)
	htmlTagRe := regexp.MustCompile(`<[^>]*>`)
	text = htmlTagRe.ReplaceAllString(text, "")

	// Replace multiple blank lines with double newline
	multipleNewlines := regexp.MustCompile(`\n{3,}`)
	text = multipleNewlines.ReplaceAllString(text, "\n\n")

	// Process each line: trim and wrap
	lines := strings.Split(text, "\n")
	var cleanedLines []string
	for _, line := range lines {
		line = strings.TrimRight(line, " \t")
		// Wrap long lines
		wrapped := wrapLine(line, maxLineLength)
		cleanedLines = append(cleanedLines, wrapped...)
	}
	text = strings.Join(cleanedLines, "\n")

	// Trim overall
	text = strings.TrimSpace(text)

	return text
}

// wrapLine wraps a single line to maxLength, preserving leading whitespace
func wrapLine(line string, maxLength int) []string {
	if len(line) <= maxLength {
		return []string{line}
	}

	// Don't wrap separator lines (===, ---)
	if strings.HasPrefix(strings.TrimSpace(line), "===") || strings.HasPrefix(strings.TrimSpace(line), "---") {
		return []string{line}
	}

	// Detect leading whitespace for continuation lines
	indent := ""
	for _, r := range line {
		if r == ' ' || r == '\t' {
			indent += string(r)
		} else {
			break
		}
	}

	// For list items, add extra indent for continuation
	trimmed := strings.TrimSpace(line)
	if strings.HasPrefix(trimmed, "- ") {
		indent += "  "
	}

	var wrapped []string
	remaining := line

	for len(remaining) > maxLength {
		// Find last space before maxLength
		breakPoint := maxLength
		for i := maxLength; i > 0; i-- {
			if remaining[i] == ' ' {
				breakPoint = i
				break
			}
		}

		// If no space found, force break at maxLength
		if breakPoint == maxLength && !strings.Contains(remaining[:maxLength], " ") {
			breakPoint = maxLength
		}

		wrapped = append(wrapped, remaining[:breakPoint])
		remaining = indent + strings.TrimLeft(remaining[breakPoint:], " ")
	}

	if len(remaining) > 0 {
		wrapped = append(wrapped, remaining)
	}

	return wrapped
}