1package view
  2
  3import (
  4	"bytes"
  5	"encoding/base64"
  6	"fmt"
  7	"image"
  8	"image/png"
  9	"io"
 10	"mime/quotedprintable"
 11	"net/http"
 12	"os"
 13	"regexp"
 14	"strings"
 15	"time"
 16
 17	_ "image/gif"
 18	_ "image/jpeg"
 19
 20	"github.com/PuerkitoBio/goquery"
 21	"github.com/charmbracelet/lipgloss"
 22	"github.com/yuin/goldmark"
 23	"github.com/yuin/goldmark/renderer/html"
 24	"golang.org/x/sys/unix"
 25)
 26
 27// getTerminalCellSize returns the height of a terminal cell in pixels.
 28// It queries the terminal using TIOCGWINSZ to get both character and pixel dimensions.
 29// Falls back to a default of 18 pixels if the query fails.
 30func getTerminalCellSize() int {
 31	const defaultCellHeight = 18
 32
 33	// Try stdout, stdin, stderr, then /dev/tty as last resort
 34	fds := []int{int(os.Stdout.Fd()), int(os.Stdin.Fd()), int(os.Stderr.Fd())}
 35
 36	for _, fd := range fds {
 37		if cellHeight := getCellHeightFromFd(fd); cellHeight > 0 {
 38			return cellHeight
 39		}
 40	}
 41
 42	// Try /dev/tty directly - this works even when stdio is redirected (e.g., in Bubble Tea)
 43	if tty, err := os.Open("/dev/tty"); err == nil {
 44		defer tty.Close()
 45		if cellHeight := getCellHeightFromFd(int(tty.Fd())); cellHeight > 0 {
 46			return cellHeight
 47		}
 48	}
 49
 50	debugImageProtocol("using default cell height: %d pixels", defaultCellHeight)
 51	return defaultCellHeight
 52}
 53
 54// getCellHeightFromFd attempts to get the terminal cell height from a file descriptor.
 55// Returns 0 if it fails or if pixel dimensions are not available.
 56func getCellHeightFromFd(fd int) int {
 57	ws, err := unix.IoctlGetWinsize(fd, unix.TIOCGWINSZ)
 58	if err != nil {
 59		return 0
 60	}
 61
 62	// ws.Row = number of character rows
 63	// ws.Ypixel = height in pixels
 64	// Some terminals don't report pixel dimensions (return 0)
 65	if ws.Row > 0 && ws.Ypixel > 0 {
 66		cellHeight := int(ws.Ypixel) / int(ws.Row)
 67		if cellHeight > 0 {
 68			debugImageProtocol("terminal cell height: %d pixels (rows=%d, ypixel=%d, fd=%d)", cellHeight, ws.Row, ws.Ypixel, fd)
 69			return cellHeight
 70		}
 71	}
 72
 73	// Terminal reported dimensions but no pixel info - this is common
 74	if ws.Row > 0 && ws.Ypixel == 0 {
 75		debugImageProtocol("terminal fd=%d has rows=%d but no pixel info (ypixel=0)", fd, ws.Row)
 76	}
 77
 78	return 0
 79}
 80
 81// hyperlinkSupported checks if the terminal supports OSC 8 hyperlinks.
 82func hyperlinkSupported() bool {
 83	term := strings.ToLower(os.Getenv("TERM"))
 84
 85	// Terminals known to support OSC 8 hyperlinks
 86	supportedTerms := []string{
 87		"kitty",
 88		"ghostty",
 89		"wezterm",
 90		"alacritty",
 91		"foot",
 92		"tmux",
 93		"screen",
 94	}
 95
 96	for _, supported := range supportedTerms {
 97		if strings.Contains(term, supported) {
 98			return true
 99		}
100	}
101
102	// Check for specific terminal programs
103	termProgram := strings.ToLower(os.Getenv("TERM_PROGRAM"))
104	supportedPrograms := []string{
105		"iterm.app",
106		"hyper",
107		"vscode",
108		"ghostty",
109		"wezterm",
110	}
111
112	for _, supported := range supportedPrograms {
113		if strings.Contains(termProgram, supported) {
114			return true
115		}
116	}
117
118	// Check for VTE-based terminals (GNOME Terminal, etc.)
119	if os.Getenv("VTE_VERSION") != "" {
120		return true
121	}
122
123	// Check for specific environment variables that indicate hyperlink support
124	if os.Getenv("KITTY_WINDOW_ID") != "" ||
125		os.Getenv("GHOSTTY_RESOURCES_DIR") != "" ||
126		os.Getenv("WEZTERM_EXECUTABLE") != "" {
127		return true
128	}
129
130	return false
131}
132
133// hyperlink formats a string as either a terminal-clickable hyperlink or plain text with URL.
134func hyperlink(url, text string) string {
135	if text == "" {
136		text = url
137	}
138
139	supported := hyperlinkSupported()
140
141	if supported {
142		// Use OSC 8 hyperlink sequence for supported terminals
143		return fmt.Sprintf("\x1b]8;;%s\x07%s\x1b]8;;\x07", url, text)
144	} else {
145		// Fallback to plain text format for unsupported terminals
146		if text == url {
147			return fmt.Sprintf("<%s>", url)
148		}
149		return fmt.Sprintf("%s <%s>", text, url)
150	}
151}
152
153func decodeQuotedPrintable(s string) (string, error) {
154	reader := quotedprintable.NewReader(strings.NewReader(s))
155	body, err := io.ReadAll(reader)
156	if err != nil {
157		return "", err
158	}
159	return string(body), nil
160}
161
162// markdownToHTML converts a Markdown string to an HTML string.
163func markdownToHTML(md []byte) []byte {
164	var buf bytes.Buffer
165	p := goldmark.New(
166		goldmark.WithRendererOptions(
167			html.WithUnsafe(), // Allow raw HTML in email.
168		),
169	)
170	if err := p.Convert(md, &buf); err != nil {
171		return md // Fallback to original markdown.
172	}
173	return buf.Bytes()
174}
175
176func kittySupported() bool {
177	term := strings.ToLower(os.Getenv("TERM"))
178	if strings.Contains(term, "kitty") {
179		return true
180	}
181	return os.Getenv("KITTY_WINDOW_ID") != ""
182}
183
184func ghosttySupported() bool {
185	// Check for TERM containing ghostty
186	term := strings.ToLower(os.Getenv("TERM"))
187	if strings.Contains(term, "ghostty") {
188		return true
189	}
190
191	// Check for Ghostty-specific environment variables
192	if os.Getenv("TERM_PROGRAM") == "ghostty" {
193		return true
194	}
195
196	// Check for GHOSTTY_RESOURCES_DIR which Ghostty sets
197	return os.Getenv("GHOSTTY_RESOURCES_DIR") != ""
198}
199
200// imageProtocolSupported checks if any supported image protocol terminal is detected.
201func imageProtocolSupported() bool {
202	return kittySupported() || ghosttySupported()
203}
204
205func debugImageProtocol(format string, args ...interface{}) {
206	if os.Getenv("DEBUG_IMAGE_PROTOCOL") == "" && os.Getenv("DEBUG_KITTY_IMAGES") == "" {
207		return
208	}
209	msg := fmt.Sprintf("[img-protocol] "+format+"\n", args...)
210	fmt.Print(msg)
211	if path := os.Getenv("DEBUG_IMAGE_PROTOCOL_LOG"); path != "" {
212		if f, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644); err == nil {
213			_, _ = f.WriteString(msg)
214			_ = f.Close()
215		}
216	} else if path := os.Getenv("DEBUG_KITTY_LOG"); path != "" {
217		if f, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644); err == nil {
218			_, _ = f.WriteString(msg)
219			_ = f.Close()
220		}
221	}
222}
223
224func fetchRemoteBase64(url string) string {
225	if !strings.HasPrefix(url, "http://") && !strings.HasPrefix(url, "https://") {
226		return ""
227	}
228	client := &http.Client{Timeout: 5 * time.Second}
229	resp, err := client.Get(url)
230	if err != nil {
231		debugImageProtocol("remote fetch failed url=%s err=%v", url, err)
232		return ""
233	}
234	defer resp.Body.Close()
235	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
236		debugImageProtocol("remote fetch non-200 url=%s status=%d", url, resp.StatusCode)
237		return ""
238	}
239	data, err := io.ReadAll(resp.Body)
240	if err != nil {
241		debugImageProtocol("remote fetch read error url=%s err=%v", url, err)
242		return ""
243	}
244
245	img, _, err := image.Decode(bytes.NewReader(data))
246	if err != nil {
247		debugImageProtocol("remote decode failed url=%s err=%v", url, err)
248		return ""
249	}
250
251	var buf bytes.Buffer
252	if err := png.Encode(&buf, img); err != nil {
253		debugImageProtocol("remote png encode failed url=%s err=%v", url, err)
254		return ""
255	}
256
257	encoded := base64.StdEncoding.EncodeToString(buf.Bytes())
258	debugImageProtocol("remote fetch ok url=%s len=%d", url, len(encoded))
259	return encoded
260}
261
262func dataURIBase64(uri string) string {
263	if !strings.HasPrefix(uri, "data:") {
264		return ""
265	}
266	comma := strings.Index(uri, ",")
267	if comma == -1 || comma+1 >= len(uri) {
268		return ""
269	}
270	return uri[comma+1:]
271}
272
273// imageRowPlaceholderPrefix is used to mark where image row spacing should be inserted.
274// This prevents the newline-collapsing regex from removing intentional spacing.
275// Uses brackets instead of angle brackets to avoid being interpreted as HTML tags.
276const imageRowPlaceholderPrefix = "[[MATCHA_IMG_ROWS:"
277const imageRowPlaceholderSuffix = "]]"
278
279func kittyInlineImage(payload string) string {
280	if payload == "" {
281		return ""
282	}
283
284	const chunkSize = 4096
285	var b strings.Builder
286
287	// Calculate how many terminal rows the image occupies to advance text after it.
288	rows := 1
289	if data, err := base64.StdEncoding.DecodeString(payload); err == nil {
290		if img, _, err := image.Decode(bytes.NewReader(data)); err == nil {
291			cellHeight := getTerminalCellSize()
292			h := img.Bounds().Dy()
293			rows = (h + cellHeight - 1) / cellHeight
294			if rows < 1 {
295				rows = 1
296			}
297			debugImageProtocol("image height: %d pixels, cell height: %d pixels, rows needed: %d", h, cellHeight, rows)
298		}
299	}
300
301	for offset := 0; offset < len(payload); offset += chunkSize {
302		end := offset + chunkSize
303		if end > len(payload) {
304			end = len(payload)
305		}
306		more := "0"
307		if end < len(payload) {
308			more = "1"
309		}
310
311		chunk := payload[offset:end]
312		if offset == 0 {
313			// C=1 means cursor does NOT move after image render (stays at top-left of image position)
314			// This is needed for proper TUI rendering, but we must add newlines to push text below
315			b.WriteString(fmt.Sprintf("\x1b_Gf=100,a=T,q=2,C=1,m=%s;%s\x1b\\", more, chunk))
316		} else {
317			b.WriteString(fmt.Sprintf("\x1b_Gm=%s;%s\x1b\\", more, chunk))
318		}
319	}
320
321	// Add newlines to push cursor below the image.
322	// Use a placeholder that won't be collapsed by the newline regex.
323	b.WriteString(fmt.Sprintf("\n%s%d%s\n", imageRowPlaceholderPrefix, rows, imageRowPlaceholderSuffix))
324
325	return b.String()
326}
327
328// expandImageRowPlaceholders replaces image row placeholders with actual newlines.
329func expandImageRowPlaceholders(text string) string {
330	re := regexp.MustCompile(regexp.QuoteMeta(imageRowPlaceholderPrefix) + `(\d+)` + regexp.QuoteMeta(imageRowPlaceholderSuffix))
331	return re.ReplaceAllStringFunc(text, func(match string) string {
332		// Extract the number of rows from the placeholder
333		numStr := strings.TrimPrefix(match, imageRowPlaceholderPrefix)
334		numStr = strings.TrimSuffix(numStr, imageRowPlaceholderSuffix)
335		rows := 1
336		if _, err := fmt.Sscanf(numStr, "%d", &rows); err != nil || rows < 1 {
337			rows = 1
338		}
339		// Return the newlines needed to push content below the image
340		return strings.Repeat("\n", rows)
341	})
342}
343
344type InlineImage struct {
345	CID    string
346	Base64 string
347}
348
349// ProcessBodyWithInline renders the body and resolves CID inline images when provided.
350func ProcessBodyWithInline(rawBody string, inline []InlineImage, h1Style, h2Style, bodyStyle lipgloss.Style) (string, error) {
351	inlineMap := make(map[string]string, len(inline))
352	for _, img := range inline {
353		cid := strings.TrimSpace(img.CID)
354		cid = strings.TrimPrefix(cid, "<")
355		cid = strings.TrimSuffix(cid, ">")
356		cid = strings.TrimPrefix(cid, "cid:")
357		if cid == "" || img.Base64 == "" {
358			continue
359		}
360		inlineMap[cid] = img.Base64
361	}
362	return processBody(rawBody, inlineMap, h1Style, h2Style, bodyStyle)
363}
364
365// ProcessBody takes a raw email body, decodes it, and formats it as plain
366// text with terminal hyperlinks.
367func ProcessBody(rawBody string, h1Style, h2Style, bodyStyle lipgloss.Style) (string, error) {
368	return processBody(rawBody, nil, h1Style, h2Style, bodyStyle)
369}
370
371func processBody(rawBody string, inline map[string]string, h1Style, h2Style, bodyStyle lipgloss.Style) (string, error) {
372	decodedBody, err := decodeQuotedPrintable(rawBody)
373	if err != nil {
374		decodedBody = rawBody
375	}
376
377	htmlBody := markdownToHTML([]byte(decodedBody))
378
379	doc, err := goquery.NewDocumentFromReader(bytes.NewReader(htmlBody))
380	if err != nil {
381		return "", fmt.Errorf("could not parse email body: %w", err)
382	}
383
384	doc.Find("style, script").Remove()
385
386	// Style headers by setting their text content.
387	// We use SetText so the h1/h2 tags remain in the document for spacing logic.
388	doc.Find("h1").Each(func(i int, s *goquery.Selection) {
389		s.SetText(h1Style.Render(s.Text()))
390	})
391
392	doc.Find("h2").Each(func(i int, s *goquery.Selection) {
393		s.SetText(h2Style.Render(s.Text()))
394	})
395
396	// Add newlines after block elements for better spacing.
397	doc.Find("p, div, h1, h2").Each(func(i int, s *goquery.Selection) {
398		s.After("\n\n")
399	})
400
401	// Replace <br> tags with newlines
402	doc.Find("br").Each(func(i int, s *goquery.Selection) {
403		s.ReplaceWithHtml("\n")
404	})
405
406	// Format links and images
407	doc.Find("a").Each(func(i int, s *goquery.Selection) {
408		href, exists := s.Attr("href")
409		if !exists {
410			return
411		}
412		s.ReplaceWithHtml(hyperlink(href, s.Text()))
413	})
414
415	doc.Find("img").Each(func(i int, s *goquery.Selection) {
416		src, exists := s.Attr("src")
417		if !exists {
418			return
419		}
420		alt, _ := s.Attr("alt")
421		if alt == "" {
422			alt = "Does not contain alt text"
423		}
424
425		if imageProtocolSupported() {
426			var payload string
427			if strings.HasPrefix(src, "data:image/") {
428				payload = dataURIBase64(src)
429			} else if strings.HasPrefix(src, "cid:") {
430				cid := strings.TrimPrefix(src, "cid:")
431				cid = strings.Trim(cid, "<>")
432				if inline != nil {
433					payload = inline[cid]
434					debugImageProtocol("cid lookup for %s found=%t len=%d", cid, payload != "", len(payload))
435				} else {
436					debugImageProtocol("cid lookup skipped inline map nil for %s", cid)
437				}
438			} else if strings.HasPrefix(src, "http://") || strings.HasPrefix(src, "https://") {
439				payload = fetchRemoteBase64(src)
440			}
441
442			if payload != "" {
443				if rendered := kittyInlineImage(payload); rendered != "" {
444					debugImageProtocol("rendered inline image src=%s len=%d dataURI=%t cid=%t (kitty=%t ghostty=%t)", src, len(payload), strings.HasPrefix(src, "data:"), strings.HasPrefix(src, "cid:"), kittySupported(), ghosttySupported())
445					s.ReplaceWithHtml("\n" + rendered + "\n")
446					return
447				}
448				debugImageProtocol("payload present but renderer returned empty src=%s len=%d", src, len(payload))
449			} else {
450				debugImageProtocol("no payload for src=%s dataURI=%t cid=%t", src, strings.HasPrefix(src, "data:"), strings.HasPrefix(src, "cid:"))
451			}
452		} else {
453			debugImageProtocol("image protocol not supported for src=%s (kitty=%t ghostty=%t)", src, kittySupported(), ghosttySupported())
454		}
455		if hyperlinkSupported() {
456			s.ReplaceWithHtml(hyperlink(src, fmt.Sprintf("\n [Click here to view image: %s] \n", alt)))
457		} else {
458			s.ReplaceWithHtml(fmt.Sprintf("\n [Image: %s, %s] \n", alt, src))
459		}
460	})
461
462	text := doc.Text()
463
464	// Collapse excessive newlines, but not the image row placeholders
465	re := regexp.MustCompile(`\n{3,}`)
466	text = re.ReplaceAllString(text, "\n\n")
467
468	// Now expand the image row placeholders to actual newlines
469	text = expandImageRowPlaceholders(text)
470
471	return bodyStyle.Render(text), nil
472}