package com.peachpasswords.ui.components

import androidx.compose.animation.core.LinearEasing
import androidx.compose.animation.core.animateFloatAsState
import androidx.compose.animation.core.tween
import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.rounded.Check
import androidx.compose.material.icons.rounded.ContentCopy
import androidx.compose.material3.Icon
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.draw.drawBehind
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp
import com.peachpasswords.ui.theme.LocalPeachAccent
import com.peachpasswords.ui.theme.LocalReduceMotion
import com.peachpasswords.ui.theme.peachColors

/**
 * Copy button with the two-effect copy feedback (spec §4.4): a diagonal sheen
 * sweeps once over ~600ms and an accent drain bar fills 0→100% over 1.4s. Both
 * collapse instantly when the copied latch clears, and are skipped under
 * reduce-motion.
 *
 * Extracted from EntryDetailScreen so the generator drawer (EntryEditScreen,
 * detail bottom sheet) can reuse the identical drain animation.
 */
@Composable
fun CopyButton(copied: Boolean, onCopy: () -> Unit) {
    val accent = LocalPeachAccent.current
    val reduceMotion = LocalReduceMotion.current
    val animate = copied && !reduceMotion
    val drain by animateFloatAsState(
        targetValue = if (copied) 1f else 0f,
        animationSpec = if (animate) tween(1400, easing = LinearEasing) else tween(0),
        label = "copy-drain",
    )
    val sheen by animateFloatAsState(
        targetValue = if (copied) 1f else 0f,
        animationSpec = if (animate) tween(600, easing = LinearEasing) else tween(0),
        label = "copy-sheen",
    )
    Box(
        Modifier
            .size(36.dp)
            .clip(RoundedCornerShape(6.dp))
            .background(peachColors.S2)
            .clickable(onClick = onCopy)
            .drawBehind {
                if (animate && sheen < 1f) {
                    val sweepX = (sheen * 2f - 0.5f) * size.width
                    val band = size.width * 0.5f
                    drawRect(
                        brush = Brush.linearGradient(
                            colors = listOf(Color.Transparent, accent.copy(alpha = 0.35f), Color.Transparent),
                            start = Offset(sweepX - band, 0f),
                            end = Offset(sweepX + band, size.height),
                        ),
                    )
                }
                if (drain > 0f) {
                    val h = 2.dp.toPx()
                    drawRect(
                        color = accent,
                        topLeft = Offset(0f, size.height - h),
                        size = Size(size.width * drain, h),
                    )
                }
            },
        contentAlignment = Alignment.Center,
    ) {
        Icon(
            if (copied) Icons.Rounded.Check else Icons.Rounded.ContentCopy,
            contentDescription = "copy",
            tint = if (copied) accent else peachColors.T1,
            modifier = Modifier.size(15.dp),
        )
    }
}