feat: add video and audio card support to MobiledocBuilder

- Add 8-param build() overload accepting videoUrl and audioUrl
- Video card: ["video",{"src":"url","loop":false}]
- Audio card: ["audio",{"src":"url"}]
- Card order: images -> video -> audio -> bookmark
- Add tests for video only, audio only, and all media types combined

app/src/main/java/com/swoosh/microblog/data/MobiledocBuilder.kt

@@ -62,6 +62,24 @@ object MobiledocBuilder {
         linkTitle: String?,
         linkDescription: String?,
         imageAlt: String?
+    ): String {
+        return build(text, imageUrls, linkUrl, linkTitle, linkDescription, imageAlt, null, null)
+    }
+
+    /**
+     * Builds mobiledoc JSON with support for images, video, audio, and bookmark cards.
+     *
+     * Card order: images -> video -> audio -> bookmark
+     */
+    fun build(
+        text: String,
+        imageUrls: List<String>,
+        linkUrl: String?,
+        linkTitle: String?,
+        linkDescription: String?,
+        imageAlt: String?,
+        videoUrl: String?,
+        audioUrl: String?
     ): String {
         val escapedText = escapeForJson(text).replace("\n", "\\n")
 
@@ -77,6 +95,20 @@ object MobiledocBuilder {
             cardSections.add("[10,${cards.size - 1}]")
         }
 
+        // Add video card if present
+        if (videoUrl != null) {
+            val escapedUrl = escapeForJson(videoUrl)
+            cards.add("""["video",{"src":"$escapedUrl","loop":false}]""")
+            cardSections.add("[10,${cards.size - 1}]")
+        }
+
+        // Add audio card if present
+        if (audioUrl != null) {
+            val escapedUrl = escapeForJson(audioUrl)
+            cards.add("""["audio",{"src":"$escapedUrl"}]""")
+            cardSections.add("[10,${cards.size - 1}]")
+        }
+
         // Add bookmark card if link is present
         if (linkUrl != null) {
             val escapedUrl = escapeForJson(linkUrl)

app/src/test/java/com/swoosh/microblog/data/MobiledocBuilderTest.kt

@@ -597,4 +597,131 @@ class MobiledocBuilderTest {
         val secondCard = cards.get(1).asJsonArray.get(1).asJsonObject
         assertEquals("", secondCard.get("alt").asString)
     }
+
+    // --- Video card tests ---
+
+    @Test
+    fun `build with video only produces valid JSON with video card`() {
+        val result = MobiledocBuilder.build(
+            "Check this video", emptyList(), null, null, null, null,
+            "https://example.com/video.mp4", null
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        assertNotNull(json)
+
+        val cards = json.getAsJsonArray("cards")
+        assertEquals(1, cards.size())
+        val card = cards.get(0).asJsonArray
+        assertEquals("video", card.get(0).asString)
+        val cardData = card.get(1).asJsonObject
+        assertEquals("https://example.com/video.mp4", cardData.get("src").asString)
+        assertFalse(cardData.get("loop").asBoolean)
+    }
+
+    @Test
+    fun `build with video has correct sections`() {
+        val result = MobiledocBuilder.build(
+            "Text", emptyList(), null, null, null, null,
+            "https://example.com/video.mp4", null
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val sections = json.getAsJsonArray("sections")
+        assertEquals("Should have text section + video card section", 2, sections.size())
+
+        val videoSection = sections.get(1).asJsonArray
+        assertEquals(10, videoSection.get(0).asInt)
+        assertEquals(0, videoSection.get(1).asInt)
+    }
+
+    // --- Audio card tests ---
+
+    @Test
+    fun `build with audio only produces valid JSON with audio card`() {
+        val result = MobiledocBuilder.build(
+            "Listen to this", emptyList(), null, null, null, null,
+            null, "https://example.com/audio.mp3"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        assertNotNull(json)
+
+        val cards = json.getAsJsonArray("cards")
+        assertEquals(1, cards.size())
+        val card = cards.get(0).asJsonArray
+        assertEquals("audio", card.get(0).asString)
+        val cardData = card.get(1).asJsonObject
+        assertEquals("https://example.com/audio.mp3", cardData.get("src").asString)
+    }
+
+    @Test
+    fun `build with audio has correct sections`() {
+        val result = MobiledocBuilder.build(
+            "Text", emptyList(), null, null, null, null,
+            null, "https://example.com/audio.mp3"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val sections = json.getAsJsonArray("sections")
+        assertEquals("Should have text section + audio card section", 2, sections.size())
+    }
+
+    // --- Combined: text + images + video + audio + bookmark ---
+
+    @Test
+    fun `build with all media types produces valid JSON with correct card order`() {
+        val images = listOf("https://example.com/img1.jpg", "https://example.com/img2.jpg")
+        val result = MobiledocBuilder.build(
+            "Full post", images,
+            "https://link.com", "Link Title", "Link Desc",
+            "Alt text",
+            "https://example.com/video.mp4",
+            "https://example.com/audio.mp3"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        assertNotNull(json)
+
+        val cards = json.getAsJsonArray("cards")
+        // 2 images + 1 video + 1 audio + 1 bookmark = 5 cards
+        assertEquals(5, cards.size())
+
+        // Verify card order: image, image, video, audio, bookmark
+        assertEquals("image", cards.get(0).asJsonArray.get(0).asString)
+        assertEquals("image", cards.get(1).asJsonArray.get(0).asString)
+        assertEquals("video", cards.get(2).asJsonArray.get(0).asString)
+        assertEquals("audio", cards.get(3).asJsonArray.get(0).asString)
+        assertEquals("bookmark", cards.get(4).asJsonArray.get(0).asString)
+
+        // Verify sections: 1 text + 5 card sections = 6
+        val sections = json.getAsJsonArray("sections")
+        assertEquals(6, sections.size())
+
+        // Verify card section indices are sequential
+        for (i in 0 until 5) {
+            val cardSection = sections.get(i + 1).asJsonArray
+            assertEquals(10, cardSection.get(0).asInt)
+            assertEquals(i, cardSection.get(1).asInt)
+        }
+    }
+
+    @Test
+    fun `build with video and audio but no images produces correct cards`() {
+        val result = MobiledocBuilder.build(
+            "Media post", emptyList(), null, null, null, null,
+            "https://example.com/video.mp4",
+            "https://example.com/audio.mp3"
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        val cards = json.getAsJsonArray("cards")
+        assertEquals(2, cards.size())
+        assertEquals("video", cards.get(0).asJsonArray.get(0).asString)
+        assertEquals("audio", cards.get(1).asJsonArray.get(0).asString)
+    }
+
+    @Test
+    fun `build with video URL containing special chars produces valid JSON`() {
+        val result = MobiledocBuilder.build(
+            "Text", emptyList(), null, null, null, null,
+            "https://example.com/video?id=1&name=\"test\"", null
+        )
+        val json = JsonParser.parseString(result).asJsonObject
+        assertNotNull(json)
+    }
 }