Inbound20260114/app/src/main/java/com/sw/inbound/activity/LocalImagePreviewActivity.kt

package com.sw.inbound.activity

import android.app.Dialog
import android.content.Context
import android.graphics.Color
import android.os.Bundle
import android.view.LayoutInflater
import android.view.ViewGroup
import android.view.WindowManager
import androidx.core.graphics.drawable.toDrawable
import androidx.lifecycle.lifecycleScope
import com.sw.inbound.base.BaseActivity
import androidx.recyclerview.widget.GridLayoutManager
import coil.load
import com.chad.library.adapter4.BaseQuickAdapter
import com.chad.library.adapter4.viewholder.QuickViewHolder
import com.sw.inbound.databinding.ActivityLocalImagePreviewBinding
import com.sw.inbound.databinding.DialogImageFullPreviewBinding
import com.sw.inbound.databinding.ListItemImagePreviewBinding
import com.sw.inbound.dialog.Loading
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import java.io.File

class LocalImagePreviewActivity : BaseActivity() {

    private lateinit var binding: ActivityLocalImagePreviewBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityLocalImagePreviewBinding.inflate(layoutInflater)
        setContentView(binding.root)

        binding.recyclerView.let {
            it.layoutManager = GridLayoutManager(this, 6, GridLayoutManager.VERTICAL, false)
            it.adapter = imageAdapter
        }
        binding.btnBack.setOnClickListener { finish() }
        loadData()
    }

    /** 从缓存 crop 目录加载所有图片文件 */
    fun loadData() {
        lifecycleScope.launch {
            // 主线程显示加载框
            Loading.show(this@LocalImagePreviewActivity)
            // 切换到 IO 线程执行文件读取
            withContext(Dispatchers.IO) {
                val cropFile = File(this@LocalImagePreviewActivity.cacheDir, "crop")
                cropFile.listFiles()?.forEach {
                    // 跳过子目录，只处理文件
                    if (it.isDirectory) return@forEach
                    // 跳过非 jpg 图片
                    if (!it.name.endsWith(".jpg", ignoreCase = true)) return@forEach
                    val nameWithoutExt = it.nameWithoutExtension
                    // 兼容 IMG_CROP_{时间戳} 和其他命名格式
                    val displayName = if (nameWithoutExt.startsWith("IMG_CROP_")) {
                        nameWithoutExt.removePrefix("IMG_CROP_")
                    } else {
                        nameWithoutExt
                    }
                    imageList.add(ImageBean(file = it, name = displayName))
                }
                // 按文件名升序排列
                imageList.sortBy { it.name }
            }
            // 回到主线程刷新列表
            imageAdapter.notifyDataSetChanged()
            // 延迟 500ms 后关闭加载框
            delay(500)
            Loading.dismiss()
        }
    }

    /** 弹出全屏大图预览 Dialog，支持左右切换 */
    private fun showFullImagePreview(startPosition: Int) {
        var currentIndex = startPosition

        val dialogBinding = DialogImageFullPreviewBinding.inflate(layoutInflater)
        val dialog = Dialog(this, android.R.style.Theme_Black_NoTitleBar_Fullscreen)
        dialog.setContentView(dialogBinding.root)
        dialog.setCancelable(true)
        dialog.setCanceledOnTouchOutside(true)
        dialog.window?.apply {
            setBackgroundDrawable(Color.TRANSPARENT.toDrawable())
            setLayout(
                WindowManager.LayoutParams.MATCH_PARENT,
                WindowManager.LayoutParams.MATCH_PARENT
            )
        }

        /** 根据 currentIndex 刷新图片、文件名、页码及按钮状态 */
        fun updateContent() {
            val item = imageList[currentIndex]
            dialogBinding.ivFullImage.load(item.file)
            dialogBinding.tvFileName.text = item.file.name
            dialogBinding.tvPageIndicator.text = "${currentIndex + 1} / ${imageList.size}"
            // 到达边界时隐藏对应方向的按钮
            dialogBinding.btnPrev.alpha = if (currentIndex > 0) 1f else 0.2f
            dialogBinding.btnNext.alpha = if (currentIndex < imageList.size - 1) 1f else 0.2f
        }

        // 点击图片本身关闭弹窗
        dialogBinding.ivFullImage.setOnClickListener { dialog.dismiss() }
        // 关闭按钮
        dialogBinding.btnClose.setOnClickListener { dialog.dismiss() }
        // 上一张
        dialogBinding.btnPrev.setOnClickListener {
            if (currentIndex > 0) {
                currentIndex--
                updateContent()
            }
        }
        // 下一张
        dialogBinding.btnNext.setOnClickListener {
            if (currentIndex < imageList.size - 1) {
                currentIndex++
                updateContent()
            }
        }

        updateContent()
        dialog.show()
    }

    private val imageList = mutableListOf<ImageBean>()
    private val imageAdapter: ImageAdapter by lazy {
        ImageAdapter(imageList).apply {
            setOnItemClickListener { _, _, position ->
                // 点击缩略图，弹出大图预览，传入当前索引以支持左右切换
                showFullImagePreview(position)
            }
        }
    }

    data class ImageBean(
        var file: File,
        var name: String
    )

    inner class ImageAdapter(var list: MutableList<ImageBean>) :
        BaseQuickAdapter<ImageBean, ImageAdapter.VH>(list) {

        inner class VH(var binding: ListItemImagePreviewBinding) : QuickViewHolder(binding.root)

        override fun onBindViewHolder(holder: VH, position: Int, item: ImageBean?) {
            holder.binding.let {
                it.imageView.load(item!!.file)
                it.textView.text = item.name
            }
        }

        override fun onCreateViewHolder(context: Context, parent: ViewGroup, viewType: Int): VH {
            val inflater = LayoutInflater.from(context)
            val binding = ListItemImagePreviewBinding.inflate(inflater, parent, false)
            return VH(binding)
        }

    }

}