package com.peachpasswords.ui.components

import androidx.compose.foundation.Image
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.runtime.LaunchedEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableIntStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.runtime.staticCompositionLocalOf
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.graphics.asImageBitmap
import androidx.compose.ui.layout.ContentScale
import androidx.compose.ui.platform.LocalDensity
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.shared.extractDomain
import com.peachpasswords.ui.theme.peachColors
import com.peachpasswords.ui.theme.PeachType

/** Favicons repository for this window; provided by MainActivity and the picker. */
val LocalFavicons = staticCompositionLocalOf<Favicons?> { null }

/**
 * Site favicon with initials fallback (offline-first). Shows the cached real
 * favicon (U1, [Favicons]) once fetched; until then the initials chip — the
 * browser's titleInitials + titleBackground port (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 favicons = LocalFavicons.current
    val domain = remember(source) { extractDomain(source) }
    var revision by remember { mutableIntStateOf(0) }
    LaunchedEffect(favicons) {
        favicons?.revision?.collect { revision = it }
    }
    val sizePx = with(LocalDensity.current) { size.roundToPx() }
    val bitmap = remember(domain, revision, sizePx) {
        if (domain != null && favicons != null) favicons.bitmap(domain, sizePx) else null
    }
    if (bitmap != null) {
        Image(
            bitmap = bitmap.asImageBitmap(),
            contentDescription = null,
            contentScale = ContentScale.Crop,
            modifier = modifier
                .size(size)
                .clip(RoundedCornerShape(cornerRadius)),
        )
        return
    }
    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)
}