feat(gallery): 캐릭터 이미지 구매 기능 추가

갤러리 아이템의 구매 버튼 클릭 시 확인 다이얼로그를 표시하고,
확인 시 /api/chat/character/image/purchase API를 호출하여 이미지 URL을 갱신.
구매 성공 시 isOwned=true 처리 및 보유 비율/개수 업데이트.

app/src/main/java/kr/co/vividnext/sodalive/chat/character/CharacterApi.kt

@@ -3,11 +3,15 @@ package kr.co.vividnext.sodalive.chat.character
 import io.reactivex.rxjava3.core.Single
 import kr.co.vividnext.sodalive.chat.character.detail.detail.CharacterDetailResponse
 import kr.co.vividnext.sodalive.chat.character.detail.gallery.CharacterImageListResponse
+import kr.co.vividnext.sodalive.chat.character.detail.gallery.CharacterImagePurchaseRequest
+import kr.co.vividnext.sodalive.chat.character.detail.gallery.CharacterImagePurchaseResponse
 import kr.co.vividnext.sodalive.common.ApiResponse
 import retrofit2.http.GET
 import retrofit2.http.Header
 import retrofit2.http.Path
 import retrofit2.http.Query
+import retrofit2.http.Body
+import retrofit2.http.POST
 
 interface CharacterApi {
     @GET("/api/chat/character/main")
@@ -28,4 +32,10 @@ interface CharacterApi {
         @Query("page") page: Int,
         @Query("size") size: Int
     ): Single<ApiResponse<CharacterImageListResponse>>
+
+    @POST("/api/chat/character/image/purchase")
+    fun purchaseCharacterImage(
+        @Header("Authorization") authHeader: String,
+        @Body request: CharacterImagePurchaseRequest
+    ): Single<ApiResponse<CharacterImagePurchaseResponse>>
 }

app/src/main/java/kr/co/vividnext/sodalive/chat/character/detail/gallery/CharacterGalleryAdapter.kt

@@ -9,7 +9,8 @@ import com.bumptech.glide.Glide
 import kr.co.vividnext.sodalive.databinding.ItemCharacterGalleryBinding
 
 class CharacterGalleryAdapter(
-    private var items: List<CharacterImageListItemResponse> = emptyList()
+    private var items: List<CharacterImageListItemResponse> = emptyList(),
+    private val onClickBuy: (item: CharacterImageListItemResponse, position: Int) -> Unit = { _, _ -> }
 ) : RecyclerView.Adapter<CharacterGalleryAdapter.ViewHolder>() {
 
     inner class ViewHolder(
@@ -22,9 +23,13 @@ class CharacterGalleryAdapter(
 
             if (item.isOwned) {
                 binding.llLock.visibility = View.GONE
+                binding.btnBuy.setOnClickListener(null)
             } else {
                 binding.llLock.visibility = View.VISIBLE
                 binding.tvPrice.text = item.imagePriceCan.toString()
+                binding.btnBuy.setOnClickListener {
+                    onClickBuy(item, bindingAdapterPosition)
+                }
             }
         }
     }

app/src/main/java/kr/co/vividnext/sodalive/chat/character/detail/gallery/CharacterGalleryFragment.kt

@@ -3,6 +3,7 @@ package kr.co.vividnext.sodalive.chat.character.detail.gallery
 import android.annotation.SuppressLint
 import android.os.Bundle
 import android.view.View
+import androidx.appcompat.app.AlertDialog
 import androidx.core.graphics.toColorInt
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
@@ -20,7 +21,7 @@ class CharacterGalleryFragment : BaseFragment<FragmentCharacterGalleryBinding>(
     FragmentCharacterGalleryBinding::inflate
 ) {
     private val viewModel: CharacterGalleryViewModel by viewModel()
-    private val adapter = CharacterGalleryAdapter()
+    private lateinit var adapter: CharacterGalleryAdapter
 
     private val characterId: Long by lazy {
         arguments?.getLong("arg_character_id")
@@ -42,6 +43,9 @@ class CharacterGalleryFragment : BaseFragment<FragmentCharacterGalleryBinding>(
                 GridSpacingItemDecoration(3, 2f.dpToPx().toInt(), true)
             )
         }
+        adapter = CharacterGalleryAdapter(onClickBuy = { item, position ->
+            showPurchaseDialog(item, position)
+        })
         binding.rvGallery.adapter = adapter
 
         binding.rvGallery.addOnScrollListener(object : RecyclerView.OnScrollListener() {
@@ -100,4 +104,17 @@ class CharacterGalleryFragment : BaseFragment<FragmentCharacterGalleryBinding>(
             state.error?.let { showToast(it) }
         }
     }
+
+    private fun showPurchaseDialog(item: CharacterImageListItemResponse, position: Int) {
+        AlertDialog.Builder(requireActivity())
+            .setTitle("[구매 확인]")
+            .setMessage("선택한 이미지를 구매하시겠습니까?")
+            .setNegativeButton("취소") { dialog, _ ->
+                dialog.dismiss()
+            }
+            .setPositiveButton("${item.imagePriceCan}캔으로 구매") { dialog, _ ->
+                dialog.dismiss()
+                viewModel.purchaseImage(item.id, position)
+            }.show()
+    }
 }

app/src/main/java/kr/co/vividnext/sodalive/chat/character/detail/gallery/CharacterGalleryRepository.kt

@@ -7,4 +7,10 @@ class CharacterGalleryRepository(
 ) {
     fun getCharacterImageList(token: String, characterId: Long, page: Int, size: Int) =
         characterApi.getCharacterImageList(authHeader = token, characterId = characterId, page = page, size = size)
+
+    fun purchaseCharacterImage(token: String, imageId: Long) =
+        characterApi.purchaseCharacterImage(
+            authHeader = token,
+            request = CharacterImagePurchaseRequest(imageId = imageId)
+        )
 }

app/src/main/java/kr/co/vividnext/sodalive/chat/character/detail/gallery/CharacterGalleryViewModel.kt

@@ -30,6 +30,7 @@ class CharacterGalleryViewModel(
     private var isLastPage: Boolean = false
     private var isRequesting: Boolean = false
     private val accumulatedItems = mutableListOf<CharacterImageListItemResponse>()
+    private var isPurchasing: Boolean = false
 
     fun loadInitial(characterId: Long) {
         // 상태 초기화
@@ -51,7 +52,12 @@ class CharacterGalleryViewModel(
         val token = "Bearer ${SharedPreferenceManager.token}"
         isRequesting = true
         compositeDisposable.add(
-            repository.getCharacterImageList(token = token, characterId = characterId, page = page, size = pageSize)
+            repository.getCharacterImageList(
+                token = token,
+                characterId = characterId,
+                page = page,
+                size = pageSize
+            )
                 .subscribeOn(Schedulers.io())
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe({ response ->
@@ -68,7 +74,8 @@ class CharacterGalleryViewModel(
                         val ratio = if (total > 0) owned.toFloat() / total.toFloat() else 0f
 
                         // 마지막 페이지 판단: 새 항목이 pageSize보다 적거나, 누적 >= total
-                        isLastPage = newItems.size < pageSize || accumulatedItems.size.toLong() >= total
+                        isLastPage =
+                            newItems.size < pageSize || accumulatedItems.size.toLong() >= total
                         currentPage = page
 
                         _uiState.value = UiState(
@@ -96,4 +103,59 @@ class CharacterGalleryViewModel(
                 })
         )
     }
+
+    fun purchaseImage(imageId: Long, position: Int) {
+        if (isPurchasing) return
+        if (position < 0 || position >= accumulatedItems.size) return
+        val target = accumulatedItems[position]
+        if (target.isOwned) return
+
+        val token = "Bearer ${SharedPreferenceManager.token}"
+        isPurchasing = true
+        compositeDisposable.add(
+            repository.purchaseCharacterImage(token = token, imageId = imageId)
+                .subscribeOn(Schedulers.io())
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe({ response ->
+                    val success = response.success
+                    val data = response.data
+                    if (success && data != null) {
+                        // 응답 imageUrl로 교체, 소유 상태 true로 변경
+                        val updated = target.copy(
+                            imageUrl = data.imageUrl,
+                            isOwned = true
+                        )
+                        accumulatedItems[position] = updated
+
+                        val total = _uiState.value?.totalCount ?: accumulatedItems.size.toLong()
+                        val ownedBefore = _uiState.value?.ownedCount
+                            ?: accumulatedItems.count { it.isOwned }.toLong()
+                        val ownedAfter = ownedBefore + 1
+                        val ratio = if (total > 0) {
+                            ownedAfter.toFloat() / total.toFloat()
+                        } else {
+                            0f
+                        }
+
+                        _uiState.value = _uiState.value?.copy(
+                            ownedCount = ownedAfter,
+                            ratio = ratio,
+                            items = accumulatedItems.toList(),
+                            error = null
+                        )
+                    } else {
+                        _uiState.value = _uiState.value?.copy(
+                            error = response.message ?: "구매에 실패했습니다."
+                        )
+                    }
+                    isPurchasing = false
+                }, { throwable ->
+                    Logger.e(throwable, throwable.message ?: "")
+                    _uiState.value = _uiState.value?.copy(
+                        error = "네트워크 오류가 발생했습니다. 잠시 후 다시 시도해 주세요."
+                    )
+                    isPurchasing = false
+                })
+        )
+    }
 }

app/src/main/java/kr/co/vividnext/sodalive/chat/character/detail/gallery/CharacterImagePurchaseRequest.kt

@@ -0,0 +1,10 @@
+package kr.co.vividnext.sodalive.chat.character.detail.gallery
+
+import androidx.annotation.Keep
+import com.google.gson.annotations.SerializedName
+
+@Keep
+data class CharacterImagePurchaseRequest(
+    @SerializedName("imageId") val imageId: Long,
+    @SerializedName("container") val container: String = "aos"
+)

app/src/main/java/kr/co/vividnext/sodalive/chat/character/detail/gallery/CharacterImagePurchaseResponse.kt

@@ -0,0 +1,9 @@
+package kr.co.vividnext.sodalive.chat.character.detail.gallery
+
+import androidx.annotation.Keep
+import com.google.gson.annotations.SerializedName
+
+@Keep
+data class CharacterImagePurchaseResponse(
+    @SerializedName("imageUrl") val imageUrl: String
+)