ThemePickerPreference.kt

package moe.matsuri.nb4a.ui

import android.content.Context
import android.content.res.Resources
import android.graphics.drawable.Drawable
import android.util.AttributeSet
import android.view.Gravity
import android.view.View
import android.view.ViewGroup
import android.widget.GridLayout
import android.widget.ImageView
import android.widget.LinearLayout
import android.widget.TextView
import androidx.appcompat.app.AlertDialog
import androidx.core.content.res.ResourcesCompat
import androidx.core.content.res.TypedArrayUtils
import androidx.core.graphics.drawable.DrawableCompat
import androidx.core.view.setPadding
import androidx.preference.Preference
import androidx.preference.PreferenceViewHolder
import com.google.android.material.dialog.MaterialAlertDialogBuilder
import io.nekohasekai.sagernet.R
import io.nekohasekai.sagernet.ktx.getColorAttr
import io.nekohasekai.sagernet.utils.Theme
import kotlin.math.roundToInt

/**
 * Two-tier theme picker.
 *
 * The preference opens a modern named list of full-fledged Material 3 themes
 * (each row: preview swatch + name). A trailing "Classic colors…" row opens the
 * legacy single-accent color grid (the original swatch-grid UX).
 *
 * Both paths persist the same int [Theme] id via [persistInt] so the rest of the
 * app (Theme.getTheme / DataStore.appTheme) is unchanged.
 */
class ThemePickerPreference
@JvmOverloads constructor(
    context: Context, attrs: AttributeSet? = null, defStyle: Int = TypedArrayUtils.getAttr(
        context,
        androidx.preference.R.attr.editTextPreferenceStyle,
        android.R.attr.editTextPreferenceStyle
    )
) : Preference(
    context, attrs, defStyle
) {

    private var inited = false

    override fun onBindViewHolder(holder: PreferenceViewHolder) {
        super.onBindViewHolder(holder)

        val widgetFrame = holder.findViewById(android.R.id.widget_frame) as? LinearLayout
            ?: return

        if (!inited) {
            inited = true
            widgetFrame.addView(
                nekoImageView(context.getColorAttr(R.attr.colorPrimary), 48, 0)
            )
            widgetFrame.visibility = View.VISIBLE
        }
    }

    private fun nekoImageView(color: Int, sizeDp: Int, paddingDp: Int): ImageView {
        val factor = context.resources.displayMetrics.density
        val size = (sizeDp * factor).roundToInt()
        val paddingSize = (paddingDp * factor).roundToInt()

        return ImageView(context).apply {
            layoutParams = ViewGroup.LayoutParams(size, size)
            setPadding(paddingSize)
            setImageDrawable(nekoAtColor(resources, color))
        }
    }

    private fun nekoAtColor(res: Resources, color: Int): Drawable {
        val neko = ResourcesCompat.getDrawable(
            res, R.drawable.ic_baseline_fiber_manual_record_24, null
        )!!
        DrawableCompat.setTint(neko.mutate(), color)
        return neko
    }

    private fun dp(value: Int): Int =
        (value * context.resources.displayMetrics.density).roundToInt()

    override fun onClick() {
        super.onClick()
        showModernDialog()
    }

    /** Modern named list: one row per [Theme.MODERN_THEMES] entry + a "Classic colors…" row. */
    private fun showModernDialog() {
        lateinit var dialog: AlertDialog

        val container = LinearLayout(context).apply {
            orientation = LinearLayout.VERTICAL
            setPadding(dp(8), dp(8), dp(8), dp(8))
        }

        for (info in Theme.MODERN_THEMES) {
            container.addView(
                buildRow(
                    name = context.getString(info.nameRes),
                    swatchColor = ResourcesCompat.getColor(context.resources, info.previewColor, context.theme),
                ) {
                    select(info.id)
                    dialog.dismiss()
                }
            )
        }

        // Trailing entry: open the legacy single-accent color grid.
        container.addView(
            buildRow(
                name = context.getString(R.string.theme_classic_colors),
                swatchColor = null,
                icon = R.drawable.ic_baseline_color_lens_24,
            ) {
                dialog.dismiss()
                showClassicGrid()
            }
        )

        dialog = MaterialAlertDialogBuilder(context)
            .setTitle(title)
            .setView(container)
            .setNegativeButton(android.R.string.cancel, null)
            .show()
    }

    private fun buildRow(
        name: String,
        swatchColor: Int?,
        icon: Int? = null,
        onClick: () -> Unit,
    ): View {
        return LinearLayout(context).apply {
            orientation = LinearLayout.HORIZONTAL
            gravity = Gravity.CENTER_VERTICAL
            isClickable = true
            isFocusable = true
            setPadding(dp(16), dp(14), dp(16), dp(14))
            // Selectable item background for ripple feedback.
            val outValue = android.util.TypedValue()
            context.theme.resolveAttribute(
                android.R.attr.selectableItemBackground, outValue, true
            )
            setBackgroundResource(outValue.resourceId)
            // Announce the theme name to screen readers when the row is focused.
            contentDescription = name

            val leading = when {
                swatchColor != null -> nekoImageView(swatchColor, 28, 0)
                icon != null -> ImageView(context).apply {
                    layoutParams = ViewGroup.LayoutParams(dp(28), dp(28))
                    setImageDrawable(
                        ResourcesCompat.getDrawable(resources, icon, context.theme)?.also {
                            DrawableCompat.setTint(
                                it.mutate(), context.getColorAttr(android.R.attr.textColorPrimary)
                            )
                        }
                    )
                }
                else -> View(context).apply {
                    layoutParams = ViewGroup.LayoutParams(dp(28), dp(28))
                }
            }
            addView(leading)

            addView(TextView(context).apply {
                text = name
                setPadding(dp(16), 0, 0, 0)
                textSize = 16f
                setTextColor(context.getColorAttr(android.R.attr.textColorPrimary))
                layoutParams = LinearLayout.LayoutParams(
                    0, ViewGroup.LayoutParams.WRAP_CONTENT, 1f
                )
            })

            setOnClickListener { onClick() }
        }
    }

    /** Legacy single-accent color grid (the original swatch-grid UX). */
    private fun showClassicGrid() {
        lateinit var dialog: AlertDialog

        val grid = GridLayout(context).apply {
            columnCount = 4

            val colors = context.resources.getIntArray(R.array.material_colors)
            for ((index, color) in colors.withIndex()) {
                // Swatch index+1 is the Theme id (see Theme.kt). Skip themes that
                // are presented in the modern named list instead of the grid.
                val themeId = index + 1
                if (Theme.MODERN_THEMES.any { it.id == themeId }) continue

                addView(nekoImageView(color, 64, 0).apply {
                    contentDescription =
                        context.getString(R.string.theme_classic_color_swatch, themeId)
                    setOnClickListener {
                        select(themeId)
                        dialog.dismiss()
                    }
                })
            }
        }

        dialog = MaterialAlertDialogBuilder(context)
            .setTitle(R.string.theme_classic_colors)
            .setView(LinearLayout(context).apply {
                gravity = Gravity.CENTER
                layoutParams = ViewGroup.LayoutParams(
                    ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT
                )
                addView(grid)
            })
            .setNegativeButton(android.R.string.cancel, null)
            .show()
    }

    private fun select(themeId: Int) {
        // Match the legacy swatch-grid ordering: persist first, then notify the
        // change listener (SettingsPreferenceFragment applies/recreates).
        persistInt(themeId)
        callChangeListener(themeId)
    }
}