package main

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"html/template"
	"io"
	"log"
	"mime"
	"mime/multipart"
	"mime/quotedprintable"
	"net/http"
	"net/mail"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
	"time"

	"golang.org/x/text/encoding"
	"golang.org/x/text/encoding/charmap"
	"golang.org/x/text/encoding/japanese"
	"golang.org/x/text/encoding/korean"
	"golang.org/x/text/encoding/simplifiedchinese"
	"golang.org/x/text/encoding/traditionalchinese"
	"golang.org/x/text/encoding/unicode"
)

// Email represents a parsed email message
type Email struct {
	From     string
	Subject  string
	Date     time.Time
	Body     template.HTML
	IsRead   bool
	ID       string
	FilePath string
	FileName string
	Subdir   string
}

// ByDate implements sort.Interface for []Email based on Date field
type ByDate []Email

func (e ByDate) Len() int           { return len(e) }
func (e ByDate) Less(i, j int) bool { return e[j].Date.Before(e[i].Date) }
func (e ByDate) Swap(i, j int)      { e[i], e[j] = e[j], e[i] }

// Server struct holds the maildir path
type Server struct {
	maildirPath string
}

var (
	scriptRe = regexp.MustCompile(`(?i)<script[^>]*>[\s\S]*?</script>`)
	styleRe  = regexp.MustCompile(`(?i)<style[^>]*>[\s\S]*?</style>`)
	brRe     = regexp.MustCompile(`(?i)<br\s*/?>`)
	pdivRe   = regexp.MustCompile(`(?i)</?(p|div)[^>]*>`)
	restRe   = regexp.MustCompile(`<[^>]+>`)
	nlRe     = regexp.MustCompile(`\n{3,}`)
)

// getEncoder returns the appropriate encoder for a charset name
func getEncoder(charset string) (encoding.Encoding, error) {
	charset = strings.ToLower(strings.TrimSpace(charset))
	charset = strings.Trim(charset, `"'`)

	switch charset {
	// UTF variants
	case "utf-8", "utf8":
		return encoding.Nop, nil // UTF-8 doesn't need conversion
	case "utf-16", "utf16":
		return unicode.UTF16(unicode.LittleEndian, unicode.UseBOM), nil
	case "utf-16be":
		return unicode.UTF16(unicode.BigEndian, unicode.IgnoreBOM), nil
	case "utf-16le":
		return unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM), nil

	// ISO-8859 variants
	case "iso-8859-1", "iso88591", "latin1", "latin-1", "iso_8859-1", "iso_8859_1":
		return charmap.ISO8859_1, nil
	case "iso-8859-2", "iso88592", "latin2", "latin-2", "iso_8859-2", "iso_8859_2":
		return charmap.ISO8859_2, nil
	case "iso-8859-3", "iso88593", "latin3", "latin-3", "iso_8859-3", "iso_8859_3":
		return charmap.ISO8859_3, nil
	case "iso-8859-4", "iso88594", "latin4", "latin-4", "iso_8859-4", "iso_8859_4":
		return charmap.ISO8859_4, nil
	case "iso-8859-5", "iso88595", "iso_8859-5", "iso_8859_5":
		return charmap.ISO8859_5, nil
	case "iso-8859-6", "iso88596", "iso_8859-6", "iso_8859_6":
		return charmap.ISO8859_6, nil
	case "iso-8859-7", "iso88597", "iso_8859-7", "iso_8859_7":
		return charmap.ISO8859_7, nil
	case "iso-8859-8", "iso88598", "iso_8859-8", "iso_8859_8":
		return charmap.ISO8859_8, nil
	case "iso-8859-9", "iso88599", "latin5", "latin-5", "iso_8859-9", "iso_8859_9":
		return charmap.ISO8859_9, nil
	case "iso-8859-10", "iso885910", "latin6", "latin-6", "iso_8859-10", "iso_8859_10":
		return charmap.ISO8859_10, nil
	case "iso-8859-13", "iso885913", "iso_8859-13", "iso_8859_13":
		return charmap.ISO8859_13, nil
	case "iso-8859-14", "iso885914", "iso_8859-14", "iso_8859_14":
		return charmap.ISO8859_14, nil
	case "iso-8859-15", "iso885915", "iso_8859-15", "iso_8859_15":
		return charmap.ISO8859_15, nil
	case "iso-8859-16", "iso885916", "iso_8859-16", "iso_8859_16":
		return charmap.ISO8859_16, nil

	// Windows code pages
	case "windows-1250", "cp1250":
		return charmap.Windows1250, nil
	case "windows-1251", "cp1251":
		return charmap.Windows1251, nil
	case "windows-1252", "cp1252":
		return charmap.Windows1252, nil
	case "windows-1253", "cp1253":
		return charmap.Windows1253, nil
	case "windows-1254", "cp1254":
		return charmap.Windows1254, nil
	case "windows-1255", "cp1255":
		return charmap.Windows1255, nil
	case "windows-1256", "cp1256":
		return charmap.Windows1256, nil
	case "windows-1257", "cp1257":
		return charmap.Windows1257, nil
	case "windows-1258", "cp1258":
		return charmap.Windows1258, nil
	case "windows-874", "cp874":
		return charmap.Windows874, nil

	// KOI8 variants
	case "koi8-r", "koi8r":
		return charmap.KOI8R, nil
	case "koi8-u", "koi8u":
		return charmap.KOI8U, nil

	// Mac encodings
	case "macintosh", "mac":
		return charmap.Macintosh, nil
	case "mac-cyrillic", "maccyrillic":
		return charmap.MacintoshCyrillic, nil

	// Japanese encodings
	case "shift_jis", "shift-jis", "sjis", "shiftjis", "x-sjis":
		return japanese.ShiftJIS, nil
	case "euc-jp", "eucjp":
		return japanese.EUCJP, nil
	case "iso-2022-jp", "iso2022jp":
		return japanese.ISO2022JP, nil

	// Chinese encodings
	case "gb18030", "gb-18030":
		return simplifiedchinese.GB18030, nil
	case "gbk", "cp936", "windows-936":
		return simplifiedchinese.GBK, nil
	case "gb2312", "gb-2312", "euc-cn", "euccn":
		return simplifiedchinese.HZGB2312, nil
	case "big5", "big-5", "cp950":
		return traditionalchinese.Big5, nil

	// Korean encodings
	case "euc-kr", "euckr":
		return korean.EUCKR, nil

	// ASCII and US-ASCII are subsets of UTF-8
	case "us-ascii", "ascii":
		return encoding.Nop, nil

	default:
		// For unknown charsets, assume UTF-8
		return encoding.Nop, nil
	}
}

// convertCharset converts text from the specified charset to UTF-8
func convertCharset(data []byte, charset string) (string, error) {
	enc, err := getEncoder(charset)
	if err != nil {
		return string(data), err
	}

	if enc == encoding.Nop {
		// Already UTF-8 or ASCII
		return string(data), nil
	}

	decoder := enc.NewDecoder()
	result, err := decoder.Bytes(data)
	if err != nil {
		// If conversion fails, try to return the original
		return string(data), err
	}

	return string(result), nil
}

// decodeMIMEHeader decodes MIME encoded-word headers (RFC 2047)
func decodeMIMEHeader(header string) string {
	dec := new(mime.WordDecoder)
	dec.CharsetReader = func(charset string, input io.Reader) (io.Reader, error) {
		enc, err := getEncoder(charset)
		if err != nil {
			return input, err
		}
		if enc == encoding.Nop {
			return input, nil
		}
		return enc.NewDecoder().Reader(input), nil
	}

	decoded, err := dec.DecodeHeader(header)
	if err != nil {
		return header
	}
	return decoded
}

// stripHTML removes HTML tags and returns plain text
func stripHTML(html string) string {
	html = scriptRe.ReplaceAllString(html, "")
	html = styleRe.ReplaceAllString(html, "")
	html = brRe.ReplaceAllString(html, "\n")
	html = pdivRe.ReplaceAllString(html, "\n")
	text := restRe.ReplaceAllString(html, "")

	text = strings.ReplaceAll(text, "&nbsp;", " ")
	text = strings.ReplaceAll(text, "&lt;", "<")
	text = strings.ReplaceAll(text, "&gt;", ">")
	text = strings.ReplaceAll(text, "&amp;", "&")
	text = strings.ReplaceAll(text, "&quot;", "\"")
	text = strings.ReplaceAll(text, "&#39;", "'")
	text = strings.ReplaceAll(text, "&#x27;", "'")
	text = strings.ReplaceAll(text, "&#x2F;", "/")

	text = nlRe.ReplaceAllString(text, "\n\n")
	return strings.TrimSpace(text)
}

// extractCharset extracts the charset from a Content-Type header
func extractCharset(contentType string) string {
	if contentType == "" {
		return "utf-8"
	}

	_, params, err := mime.ParseMediaType(contentType)
	if err != nil {
		return "utf-8"
	}

	if charset, ok := params["charset"]; ok {
		return charset
	}

	return "utf-8"
}

// parseMaildir reads and parses all emails from a Maildir directory
func (s *Server) parseMaildir() ([]Email, error) {
	var emails []Email

	for _, subdir := range []string{"new", "cur"} {
		dirPath := filepath.Join(s.maildirPath, subdir)

		if _, err := os.Stat(dirPath); os.IsNotExist(err) {
			continue
		}

		files, err := os.ReadDir(dirPath)
		if err != nil {
			log.Printf("Error reading %s: %v", dirPath, err)
			continue
		}

		for _, file := range files {
			if file.IsDir() {
				continue
			}

			filePath := filepath.Join(dirPath, file.Name())

			isRead := false
			if subdir == "cur" {
				if idx := strings.LastIndex(file.Name(), ":2,"); idx != -1 {
					flags := file.Name()[idx+3:]
					isRead = strings.Contains(flags, "S")
				}
			}

			email, err := s.parseEmailFile(filePath, file.Name(), isRead, subdir)
			if err != nil {
				log.Printf("Error parsing %s: %v", filePath, err)
				continue
			}

			emails = append(emails, email)
		}
	}

	return emails, nil
}

// parseEmailFile reads and parses a single email file
func (s *Server) parseEmailFile(filePath, fileName string, isRead bool, subdir string) (Email, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return Email{}, err
	}
	defer file.Close()

	msg, err := mail.ReadMessage(file)
	if err != nil {
		return Email{}, err
	}

	from := decodeMIMEHeader(msg.Header.Get("From"))
	subject := decodeMIMEHeader(msg.Header.Get("Subject"))
	dateStr := msg.Header.Get("Date")

	var date time.Time
	if dateStr != "" {
		date, _ = mail.ParseDate(dateStr)
	}

	body, err := extractPlainTextBody(msg)
	if err != nil {
		body = "Error reading email body"
	}

	id := strings.ReplaceAll(fileName, ":", "_")
	id = strings.ReplaceAll(id, ".", "_")
	id = strings.ReplaceAll(id, ",", "_")

	return Email{
		From:     from,
		Subject:  subject,
		Date:     date,
		Body:     template.HTML(body),
		IsRead:   isRead,
		ID:       id,
		FilePath: filePath,
		FileName: fileName,
		Subdir:   subdir,
	}, nil
}

// decodeContent decodes content based on transfer encoding and charset
func decodeContent(content string, encoding string, charset string) string {
	encoding = strings.ToLower(encoding)

	// First, decode transfer encoding
	var decoded []byte
	switch encoding {
	case "base64":
		d, err := base64.StdEncoding.DecodeString(strings.TrimSpace(content))
		if err == nil {
			decoded = d
		} else {
			decoded = []byte(content)
		}
	case "quoted-printable":
		reader := quotedprintable.NewReader(strings.NewReader(content))
		d, err := io.ReadAll(reader)
		if err == nil {
			decoded = d
		} else {
			decoded = []byte(content)
		}
	default:
		decoded = []byte(content)
	}

	// Then, convert charset to UTF-8
	result, err := convertCharset(decoded, charset)
	if err != nil {
		log.Printf("Charset conversion error for %s: %v", charset, err)
		// Return best effort
		return string(decoded)
	}
	return result
}

// findTextPlainPart recursively searches for text/plain parts
func findTextPlainPart(mr *multipart.Reader) (string, bool) {
	for {
		part, err := mr.NextPart()
		if err == io.EOF {
			break
		}
		if err != nil {
			continue
		}

		partContentType := part.Header.Get("Content-Type")
		partMediaType, params, _ := mime.ParseMediaType(partContentType)
		partEncoding := part.Header.Get("Content-Transfer-Encoding")
		charset := params["charset"]
		if charset == "" {
			charset = "utf-8"
		}

		if strings.HasPrefix(partMediaType, "multipart/") {
			if boundary, ok := params["boundary"]; ok {
				bodyBytes, err := io.ReadAll(part)
				if err != nil {
					continue
				}
				subReader := multipart.NewReader(bytes.NewReader(bodyBytes), boundary)
				if text, found := findTextPlainPart(subReader); found {
					return text, true
				}
			}
		} else if partMediaType == "text/plain" {
			bodyBytes, err := io.ReadAll(part)
			if err != nil {
				continue
			}
			decoded := decodeContent(string(bodyBytes), partEncoding, charset)
			return decoded, true
		}
	}
	return "", false
}

// extractPlainTextBody extracts plaintext body content
func extractPlainTextBody(msg *mail.Message) (string, error) {
	contentType := msg.Header.Get("Content-Type")
	transferEncoding := msg.Header.Get("Content-Transfer-Encoding")
	charset := extractCharset(contentType)

	if contentType == "" {
		body, err := io.ReadAll(msg.Body)
		if err != nil {
			return "", err
		}
		decoded := decodeContent(string(body), transferEncoding, charset)
		return escapeHTML(decoded), nil
	}

	mediaType, params, err := mime.ParseMediaType(contentType)
	if err != nil {
		body, _ := io.ReadAll(msg.Body)
		decoded := decodeContent(string(body), transferEncoding, charset)
		return escapeHTML(decoded), nil
	}

	// Update charset if specified in params
	if c, ok := params["charset"]; ok {
		charset = c
	}

	if strings.HasPrefix(mediaType, "multipart/") {
		mr := multipart.NewReader(msg.Body, params["boundary"])

		msgBodyBytes, err := io.ReadAll(msg.Body)
		if err == nil {
			searchReader := multipart.NewReader(bytes.NewReader(msgBodyBytes), params["boundary"])
			if text, found := findTextPlainPart(searchReader); found {
				return escapeHTML(text), nil
			}
		}

		mr = multipart.NewReader(bytes.NewReader(msgBodyBytes), params["boundary"])
		var htmlBody string
		var htmlCharset string

		for {
			part, err := mr.NextPart()
			if err == io.EOF {
				break
			}
			if err != nil {
				return "", err
			}

			partContentType := part.Header.Get("Content-Type")
			partMediaType, partParams, _ := mime.ParseMediaType(partContentType)
			partEncoding := part.Header.Get("Content-Transfer-Encoding")

			if partMediaType == "text/html" {
				bodyBytes, err := io.ReadAll(part)
				if err != nil {
					continue
				}
				htmlCharset = partParams["charset"]
				if htmlCharset == "" {
					htmlCharset = "utf-8"
				}
				htmlBody = decodeContent(string(bodyBytes), partEncoding, htmlCharset)
			}
		}

		if htmlBody != "" {
			plainText := stripHTML(htmlBody)
			return escapeHTML(plainText), nil
		}

		return "No text content found", nil
	}

	body, err := io.ReadAll(msg.Body)
	if err != nil {
		return "", err
	}

	decoded := decodeContent(string(body), transferEncoding, charset)

	if mediaType == "text/html" {
		plainText := stripHTML(decoded)
		return escapeHTML(plainText), nil
	}

	return escapeHTML(decoded), nil
}

// escapeHTML performs HTML escaping for plain text
func escapeHTML(s string) string {
	s = strings.ReplaceAll(s, "&", "&amp;")
	s = strings.ReplaceAll(s, "<", "&lt;")
	s = strings.ReplaceAll(s, ">", "&gt;")
	s = strings.ReplaceAll(s, "\"", "&quot;")
	s = strings.ReplaceAll(s, "'", "&#39;")
	s = strings.ReplaceAll(s, "\n", "<br>")
	s = strings.ReplaceAll(s, "\r", "")
	return s
}

// indexHandler serves the main HTML page
func (s *Server) indexHandler(w http.ResponseWriter, r *http.Request) {
	fmt.Println(r.Header.Get("X-Forwarded-For"), "authorized access")

	emails, err := s.parseMaildir()
	if err != nil {
		http.Error(w, "Error reading emails", http.StatusInternalServerError)
		return
	}

	sort.Sort(ByDate(emails))

	tmplStr := `<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Genesungswünsche</title>
    <style>
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
            background: #f5f5f5;
			zoom: 1.5;
        }

        h1 {
            color: #333;
            border-bottom: 2px solid #ddd;
            padding-bottom: 10px;
        }

        .email-item {
            background: white;
            border: 1px solid #ddd;
            border-radius: 5px;
            margin-bottom: 10px;
            overflow: hidden;
        }

        .email-toggle {
            display: none;
        }

        .email-header {
            padding: 15px;
            cursor: pointer;
            user-select: none;
            transition: background 0.2s;
            display: block;
        }

        .email-header:hover {
            background: #f9f9f9;
        }

        .email-meta {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 8px;
        }

        .from {
            color: #666;
            font-size: 14px;
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
            margin-right: 15px;
        }

        .date {
            color: #999;
            font-size: 14px;
            flex-shrink: 0;
        }

        .subject-line {
            display: flex;
            align-items: center;
            justify-content: space-between;
        }

        .subject-wrapper {
            display: flex;
            align-items: center;
            flex: 1;
            overflow: hidden;
        }

        .arrow {
            flex-shrink: 0;
            transition: transform 0.3s;
            font-size: 12px;
            color: #666;
            margin-right: 8px;
        }

        .subject {
            font-size: 15px;
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
        }

        .email-item:not(.read) .subject {
            font-weight: bold;
            color: #333;
        }

        .email-item.read .subject {
            font-weight: normal;
            color: #666;
        }

        .read-toggle {
            flex-shrink: 0;
            margin-left: 0;
            margin-top: 1em;
            padding: 4px 8px;
            font-size: 12px;
            background: #f0f0f0;
            border: 1px solid #ddd;
            border-radius: 4px;
            cursor: pointer;
            transition: all 0.1s;
            color: #666;
        }

        .read-toggle:hover {
            background: #e0e0e0;
            border-color: #bbb;
        }

        .email-item:not(.read) .read-toggle {
            background: #4CAF50;
            color: white;
            border-color: #45a049;
        }

        .email-item:not(.read) .read-toggle:hover {
            background: #45a049;
        }

        .email-body {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-out, padding 0.3s ease-out;
            padding: 0 15px;
            border-top: 1px solid #eee;
        }

        .email-toggle:checked ~ .email-body {
            max-height: 2000px;
            padding: 15px;
        }

        .email-toggle:checked ~ .email-header .arrow {
            transform: rotate(90deg);
        }

        .email-content {
            line-height: 1.6;
            color: #444;
            overflow-wrap: break-word;
            white-space: pre-wrap;
        }

	ol li {
	  color: #333;
	}

        @media (max-width: 768px) {
            .from {
                font-size: 13px;
            }

            .subject {
                font-size: 14px;
            }

            .date {
                font-size: 12px;
            }

            .read-toggle {
                font-size: 11px;
                padding: 3px 6px;
            }
        }
    </style>
</head>
<body>
    <h1>Genesungswünsche</h1>
    <div id="email-list">
    <ol reversed>
        {{range .}}
	<li>
        <div class="email-item {{if .IsRead}}read{{end}}" data-id="{{.ID}}" data-filename="{{.FileName}}" data-subdir="{{.Subdir}}">
            <input type="checkbox" class="email-toggle" id="toggle-{{.ID}}">
            <label for="toggle-{{.ID}}" class="email-header">
                <div class="email-meta">
                    <span class="from">{{.From}}</span>
                    <span class="date">{{.Date.Format "2006-01-02 15:04"}}</span>
                </div>
                <div class="subject-line">
                    <div class="subject-wrapper">
                        <span class="arrow">▶</span>
                        <span class="subject">{{if .Subject}}{{.Subject}}{{else}}(No Subject){{end}}</span>
                    </div>
                </div>
            </label>
            <div class="email-body">
                <div class="email-content">{{.Body}}</div>
                <button class="read-toggle" onclick="toggleReadStatus(event, '{{.ID}}', '{{.FileName}}', '{{.Subdir}}', {{.IsRead}})">
                    {{if .IsRead}}Mark Unread{{else}}Mark Read{{end}}
                </button>
            </div>
        </div>
	</li>
        {{end}}
    </ol>
    </div>

    <script>
        document.addEventListener('DOMContentLoaded', function() {
            const checkboxes = document.querySelectorAll('.email-toggle');

            checkboxes.forEach(checkbox => {
                checkbox.addEventListener('change', function() {
                    if (this.checked) {
                        const emailItem = this.closest('.email-item');
                        const filename = emailItem.dataset.filename;
                        const subdir = emailItem.dataset.subdir;

                        // Auto-mark as read when expanding unread emails
                        if (subdir === 'new' && !emailItem.classList.contains('read')) {
                            markAsRead(filename, emailItem, true);
                        }
                    }
                });
            });
        });

        function toggleReadStatus(event, id, filename, subdir, isRead) {
            event.stopPropagation();
            event.preventDefault();

            const emailItem = document.querySelector(` + "`[data-id=\"${id}\"]`);" + `
            const button = event.target;

            if (isRead) {
                // Mark as unread
                markAsUnread(filename, emailItem, button);
            } else {
                // Mark as read
                markAsRead(filename, emailItem, false, button);
            }
        }

        function markAsRead(filename, emailItem, autoExpand = false, button = null) {
            fetch('/genesung/api/mark-read', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({
                    filename: filename
                })
            })
            .then(response => response.json())
            .then(data => {
                if (data.success) {
                    emailItem.classList.add('read');
                    emailItem.dataset.subdir = 'cur';
                    emailItem.dataset.filename = data.newFilename;

                    // Update button if it exists
                    if (button) {
                        button.textContent = 'Mark Unread';
                        button.setAttribute('onclick', 
                            ` + "`toggleReadStatus(event, '${emailItem.dataset.id}', '${data.newFilename}', 'cur', true)`);" + `
                    } else {
                        // Find and update the button
                        const btn = emailItem.querySelector('.read-toggle');
                        if (btn) {
                            btn.textContent = 'Mark Unread';
                            btn.setAttribute('onclick', 
                                ` + "`toggleReadStatus(event, '${emailItem.dataset.id}', '${data.newFilename}', 'cur', true)`);" + `
                        }
                    }
                } else {
                    console.error('Failed to mark email as read:', data.error);
                }
            })
            .catch(error => {
                console.error('Error marking email as read:', error);
            });
        }

        function markAsUnread(filename, emailItem, button) {
            fetch('/genesung/api/mark-unread', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({
                    filename: filename
                })
            })
            .then(response => response.json())
            .then(data => {
                if (data.success) {
                    emailItem.classList.remove('read');
                    emailItem.dataset.subdir = 'new';
                    emailItem.dataset.filename = data.newFilename;

                    // Update button
                    button.textContent = 'Mark Read';
                    button.setAttribute('onclick', 
                        ` + "`toggleReadStatus(event, '${emailItem.dataset.id}', '${data.newFilename}', 'new', false)`);" + `
                } else {
                    console.error('Failed to mark email as unread:', data.error);
                }
            })
            .catch(error => {
                console.error('Error marking email as unread:', error);
            });
        }
    </script>
</body>
</html>`

	tmpl, err := template.New("emails").Parse(tmplStr)
	if err != nil {
		http.Error(w, "Template error", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	tmpl.Execute(w, emails)
}

// markReadHandler handles the API request to mark an email as read
func (s *Server) markReadHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	var req struct {
		Filename string `json:"filename"`
	}

	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request", http.StatusBadRequest)
		return
	}

	if strings.ContainsAny(req.Filename, "/") {
		http.Error(w, "Invalid request", http.StatusBadRequest)
		return
	}

	sourcePath := filepath.Join(s.maildirPath, "new", req.Filename)

	if _, err := os.Stat(sourcePath); os.IsNotExist(err) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"success": false,
			"error":   "Email not found in new folder",
		})
		return
	}

	baseFilename := req.Filename
	if idx := strings.Index(baseFilename, ":2,"); idx != -1 {
		baseFilename = baseFilename[:idx]
	}

	destFilename := baseFilename + ":2,S"
	destPath := filepath.Join(s.maildirPath, "cur", destFilename)

	if err := os.Rename(sourcePath, destPath); err != nil {
		fmt.Println("mark read error: ", err)
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"success": false,
			"error":   err.Error(),
		})
		return
	}

	fmt.Println(r.Header.Get("X-Forwarded-For"),
		"mark read from",
		sourcePath, "to", destPath)

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"success":     true,
		"newFilename": destFilename,
	})
}

// markUnreadHandler handles the API request to mark an email as unread
func (s *Server) markUnreadHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	var req struct {
		Filename string `json:"filename"`
	}

	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request", http.StatusBadRequest)
		return
	}

	if strings.ContainsAny(req.Filename, "/") {
		http.Error(w, "Invalid request", http.StatusBadRequest)
		return
	}

	sourcePath := filepath.Join(s.maildirPath, "cur", req.Filename)

	if _, err := os.Stat(sourcePath); os.IsNotExist(err) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"success": false,
			"error":   "Email not found in cur folder",
		})
		return
	}

	// Remove :2,S flags when moving back to new
	baseFilename := req.Filename
	if idx := strings.Index(baseFilename, ":2,"); idx != -1 {
		baseFilename = baseFilename[:idx]
	}

	destPath := filepath.Join(s.maildirPath, "new", baseFilename)

	// Check if destination file already exists (shouldn't happen normally)
	if _, err := os.Stat(destPath); err == nil {
		// File exists, add a timestamp to make it unique
		timestamp := time.Now().UnixNano()
		baseFilename = fmt.Sprintf("%s_%d", baseFilename, timestamp)
		destPath = filepath.Join(s.maildirPath, "new", baseFilename)
	}

	if err := os.Rename(sourcePath, destPath); err != nil {
		fmt.Println("unread error: ", err)
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"success": false,
			"error":   err.Error(),
		})
		return
	}
	fmt.Println(r.Header.Get("X-Forwarded-For"),
		"mark unread from",
		sourcePath, "to", destPath)

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"success":     true,
		"newFilename": baseFilename,
	})
}

func auth(handler http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user, pass, ok := r.BasicAuth()

		if !ok || user != "secret" || pass != "lair" {
			w.Header().Set("WWW-Authenticate", `Basic realm="Genesung"`)
			http.Error(w, "Unauthorized", http.StatusUnauthorized)
			return
		}
		handler(w, r)
	}
}

func referer(handler http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Referer() != "https://www.codeblau.de/genesung/" {
			http.Error(w, "CSRF!?", http.StatusBadRequest)
			return
		}
		handler(w, r)
	}
}

func main() {
	if len(os.Args) < 2 {
		fmt.Println("Usage: go run maildir-server.go <maildir-path> [port]")
		fmt.Println("Example: go run maildir-server.go ~/Maildir 4242")
		os.Exit(1)
	}

	maildirPath := os.Args[1]
	port := "4242"
	if len(os.Args) >= 3 {
		port = os.Args[2]
	}

	server := &Server{
		maildirPath: maildirPath,
	}

	http.HandleFunc("/", auth(server.indexHandler))
	http.HandleFunc("/genesung/api/mark-read", auth(referer(server.markReadHandler)))
	http.HandleFunc("/genesung/api/mark-unread", auth(referer(server.markUnreadHandler)))

	fmt.Printf("Starting server on http://localhost:%s\n", port)
	fmt.Printf("Serving emails from: %s\n", maildirPath)

	if err := http.ListenAndServe(":"+port, nil); err != nil {
		log.Fatal("Server failed to start:", err)
	}
}