package com.craigvg.lichun_android.ui.screens.dating.components

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.*
import androidx.compose.material3.*
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.draw.shadow
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import com.craigvg.lichun_android.domain.models.Person
import com.craigvg.lichun_android.ui.theme.AppColors
import com.craigvg.lichun_android.ui.theme.AppSpacing
import com.craigvg.lichun_android.ui.theme.AppTypography
import kotlin.math.abs

/**
 * Modal explaining compatibility score breakdown
 * Ported from iOS CompatibilityExplanationView.swift
 */
@Composable
fun CompatibilityExplanationView(
    person: Person,
    currentPerson: Person,
    onDismiss: () -> Unit
) {
    val sharedInterests = person.interests.filter { interest ->
        currentPerson.interests.any { it.equals(interest, ignoreCase = true) }
    }
    val ageDifference = abs(person.ageYears - currentPerson.ageYears)
    val ageDifferenceText = when {
        ageDifference == 0 -> "Same age"
        ageDifference == 1 -> "1 year age difference"
        else -> "$ageDifference years age difference"
    }
    val statsSimilarity = run {
        val healthDiff = abs(person.health.toInt() - currentPerson.health.toInt())
        val happinessDiff = abs(person.happiness - currentPerson.happiness)
        val intelligenceDiff = abs(person.intelligence - currentPerson.intelligence)
        val prestigeDiff = abs(person.prestige - currentPerson.prestige)
        val avgDiff = (healthDiff + happinessDiff + intelligenceDiff + prestigeDiff) / 4
        (100 - avgDiff).coerceAtLeast(0)
    }

    Column(
        modifier = Modifier
            .fillMaxWidth()
            .background(
                Brush.linearGradient(
                    colors = listOf(
                        AppColors.primary.copy(alpha = 0.05f),
                        AppColors.accent.copy(alpha = 0.03f),
                        Color.Transparent
                    )
                )
            )
            .background(AppColors.background)
            .padding(AppSpacing.xl)
    ) {
        // Close button
        Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.End) {
            IconButton(
                onClick = onDismiss,
                modifier = Modifier
                    .size(32.dp)
                    .clip(CircleShape)
                    .background(AppColors.secondaryText.copy(alpha = 0.1f))
            ) {
                Icon(
                    imageVector = Icons.Default.Close,
                    contentDescription = "Close",
                    tint = AppColors.secondaryText,
                    modifier = Modifier.size(14.dp)
                )
            }
        }

        // Header
        Column(
            modifier = Modifier.fillMaxWidth(),
            horizontalAlignment = Alignment.CenterHorizontally
        ) {
            Box(
                modifier = Modifier
                    .size(80.dp)
                    .clip(CircleShape)
                    .background(
                        Brush.linearGradient(
                            colors = listOf(
                                AppColors.primary.copy(alpha = 0.2f),
                                AppColors.accent.copy(alpha = 0.15f)
                            )
                        )
                    ),
                contentAlignment = Alignment.Center
            ) {
                Icon(
                    imageVector = Icons.Default.Favorite,
                    contentDescription = null,
                    tint = AppColors.primary,
                    modifier = Modifier.size(48.dp)
                )
            }

            Spacer(modifier = Modifier.height(AppSpacing.sm))

            Text(
                text = "Why ${person.compatibilityScore}%?",
                style = AppTypography.title,
                color = AppColors.primaryText
            )
            Text(
                text = "Compatibility is based on multiple factors",
                style = AppTypography.body,
                color = AppColors.secondaryText,
                textAlign = TextAlign.Center
            )
        }

        Spacer(modifier = Modifier.height(AppSpacing.md))
        HorizontalDivider(color = AppColors.secondaryText.copy(alpha = 0.2f))
        Spacer(modifier = Modifier.height(AppSpacing.md))

        // Factors
        Column(verticalArrangement = Arrangement.spacedBy(AppSpacing.sm)) {
            if (sharedInterests.isNotEmpty()) {
                ExplanationRow(
                    icon = Icons.Default.Star,
                    text = "${sharedInterests.size} shared interest${if (sharedInterests.size == 1) "" else "s"}",
                    detail = sharedInterests.take(3).joinToString(", "),
                    positive = true,
                    impact = sharedInterests.size * 10
                )
            }

            ExplanationRow(
                icon = Icons.Default.CalendarToday,
                text = ageDifferenceText,
                detail = if (ageDifference <= 5) "Close in age" else "Larger age gap",
                positive = ageDifference <= 5,
                impact = if (ageDifference <= 5) 15 else -10
            )

            ExplanationRow(
                icon = Icons.Default.BarChart,
                text = "Similar life stats",
                detail = "$statsSimilarity% similarity across stats",
                positive = statsSimilarity >= 70,
                impact = if (statsSimilarity >= 70) 20 else 0
            )

            if (person.occupation.isNotEmpty() && currentPerson.occupation.isNotEmpty()) {
                val sameField = person.occupation.contains(currentPerson.occupation, ignoreCase = true) ||
                        currentPerson.occupation.contains(person.occupation, ignoreCase = true)
                ExplanationRow(
                    icon = Icons.Default.Work,
                    text = if (sameField) "Similar career paths" else "Different career paths",
                    detail = "${person.occupation} / ${currentPerson.occupation}",
                    positive = sameField,
                    impact = if (sameField) 10 else 0
                )
            }

            ExplanationRow(
                icon = Icons.Default.AutoAwesome,
                text = "Mystery factor",
                detail = "Some things just click!",
                positive = person.compatibilityScore >= 70,
                impact = (5..15).random()
            )
        }

        Spacer(modifier = Modifier.height(AppSpacing.lg))

        // Close button
        Button(
            onClick = onDismiss,
            modifier = Modifier
                .fillMaxWidth()
                .height(AppSpacing.buttonHeight),
            shape = RoundedCornerShape(AppSpacing.cornerRadius),
            colors = ButtonDefaults.buttonColors(containerColor = AppColors.primary)
        ) {
            Text("Got it!", style = AppTypography.headline, color = Color.White)
        }
    }
}

@Composable
private fun ExplanationRow(
    icon: androidx.compose.ui.graphics.vector.ImageVector,
    text: String,
    detail: String,
    positive: Boolean,
    impact: Int
) {
    val statusColor = if (positive) AppColors.success else AppColors.warning
    val impactColor = when {
        impact > 0 -> AppColors.success
        impact < 0 -> AppColors.error
        else -> AppColors.secondaryText
    }

    Row(
        modifier = Modifier
            .fillMaxWidth()
            .clip(RoundedCornerShape(AppSpacing.smallCornerRadius))
            .background(AppColors.surfaceElevated)
            .background(
                Brush.horizontalGradient(
                    colors = listOf(statusColor.copy(alpha = 0.05f), Color.Transparent)
                )
            )
            .padding(AppSpacing.sm),
        verticalAlignment = Alignment.Top,
        horizontalArrangement = Arrangement.spacedBy(AppSpacing.md)
    ) {
        Box(
            modifier = Modifier
                .size(32.dp)
                .clip(CircleShape)
                .background(statusColor.copy(alpha = 0.15f)),
            contentAlignment = Alignment.Center
        ) {
            Icon(
                imageVector = icon,
                contentDescription = null,
                tint = statusColor,
                modifier = Modifier.size(16.dp)
            )
        }

        Column(modifier = Modifier.weight(1f)) {
            Text(text = text, style = AppTypography.bodyBold, color = AppColors.primaryText)
            Text(text = detail, style = AppTypography.caption, color = AppColors.secondaryText)
        }

        if (impact != 0) {
            Text(
                text = "${if (impact > 0) "+" else ""}$impact",
                style = AppTypography.captionBold,
                color = impactColor,
                modifier = Modifier
                    .clip(RoundedCornerShape(8.dp))
                    .background(impactColor.copy(alpha = 0.15f))
                    .padding(horizontal = AppSpacing.sm, vertical = 4.dp)
            )
        }
    }
}