package com.peachpasswords.ui.components

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.draw.drawBehind
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.em
import androidx.compose.ui.unit.sp
import com.peachpasswords.ui.theme.peachColors
import com.peachpasswords.ui.theme.PeachType

/**
 * Initials chip used in place of a network favicon (offline-first). Ports the
 * browser titleInitials + titleBackground (deterministic HSL 32%/26%). The
 * corner radius tracks the chip size (≈6dp at 26dp, ≈3dp at 16dp) per spec §4.6.
 */
@Composable
fun FaviconInitials(
    source: String,
    modifier: Modifier = Modifier,
    size: Dp = 26.dp,
    cornerRadius: Dp = (size.value * 0.23f).dp,
) {
    val bg = titleBackground(source)
    Box(
        modifier = modifier
            .size(size)
            .clip(RoundedCornerShape(cornerRadius))
            .drawBehind { drawRect(bg) },
        contentAlignment = Alignment.Center,
    ) {
        Text(
            text = titleInitials(source),
            color = peachColors.T0.copy(alpha = 0.92f),
            fontFamily = PeachType.Mono,
            fontWeight = FontWeight.SemiBold,
            letterSpacing = 0.04.em,
            fontSize = (size.value * 0.34f).sp,
        )
    }
}

fun titleInitials(source: String): String {
    val cleaned = source.replace(Regex("^https?://"), "").removePrefix("www.").trim()
    if (cleaned.isEmpty()) return "·"
    val words = cleaned.split(Regex("[\\s.\\-_/]+")).filter { it.isNotEmpty() }
    if (words.size >= 2 && words[0].isNotEmpty() && words[1].isNotEmpty()) {
        return (words[0][0].toString() + words[1][0].toString()).uppercase()
    }
    val single = words.firstOrNull() ?: cleaned
    return single.take(2).uppercase()
}

/** Deterministic muted HSL(hue, 32%, 26%) background, matching the browser. */
fun titleBackground(source: String): Color {
    var hash = 0
    for (ch in source) hash = ((hash shl 5) - hash + ch.code)
    val hue = (((hash % 360) + 360) % 360).toFloat()
    return hsl(hue, 0.32f, 0.26f)
}

private fun hsl(h: Float, s: Float, l: Float): Color {
    val c = (1f - kotlin.math.abs(2 * l - 1f)) * s
    val x = c * (1f - kotlin.math.abs((h / 60f) % 2f - 1f))
    val m = l - c / 2f
    val (r, g, b) = when {
        h < 60 -> Triple(c, x, 0f)
        h < 120 -> Triple(x, c, 0f)
        h < 180 -> Triple(0f, c, x)
        h < 240 -> Triple(0f, x, c)
        h < 300 -> Triple(x, 0f, c)
        else -> Triple(c, 0f, x)
    }
    return Color(r + m, g + m, b + m)
}