<template>
    <div class="space-y-3">
        <!-- Grouped results when sorting by reliability -->
        <template v-if="currentSort === 'reliable'">
            <section v-if="reliable.length" class="space-y-2">
                <header class="flex items-center gap-2 pt-2">
                    <iconify-icon class="text-status-good text-lg" icon="lucide:shield-check"></iconify-icon>
                    <h3 class="font-black text-zinc-800">Reliable</h3>
                    <span class="text-xs text-zinc-500 font-medium">Updated in the last 3 days</span>
                </header>
                <StationCard
                    v-for="station in reliable"
                    :key="station.station_id"
                    :avg-pence="avgPence"
                    :lowest-price="lowestPrice"
                    :origin="origin"
                    :station="station"
                />
            </section>

            <section v-if="stale.length" class="space-y-2 pt-4">
                <header class="flex items-center gap-2">
                    <iconify-icon class="text-status-warn text-lg" icon="lucide:clock"></iconify-icon>
                    <h3 class="font-black text-zinc-800">Older prices</h3>
                    <span class="text-xs text-zinc-500 font-medium">3–7 days old — verify before driving</span>
                </header>
                <div>
                    <StationCard
                        v-for="station in stale"
                        :key="station.station_id"
                        :avg-pence="avgPence"
                        :lowest-price="lowestPrice"
                        :origin="origin"
                        :station="station"
                        class="mb-2"
                    />
                </div>
            </section>

            <section v-if="outdated.length" class="space-y-2 pt-4">
                <button
                    :aria-expanded="outdatedOpen"
                    class="flex items-center gap-2 w-full text-left py-3 px-3 rounded-lg hover:bg-zinc-100/60 transition-colors"
                    type="button"
                    @click="outdatedOpen = !outdatedOpen"
                >
                    <iconify-icon class="text-status-bad text-lg" icon="lucide:triangle-alert"></iconify-icon>
                    <h3 class="font-black text-zinc-800">Outdated</h3>
                    <span class="text-xs text-zinc-500 font-medium">Over 7 days old — likely inaccurate ({{ outdated.length }})</span>
                    <iconify-icon
                        :class="{ 'rotate-180': outdatedOpen }"
                        class="text-zinc-500 text-base ml-auto transition-transform"
                        icon="lucide:chevron-down"
                    ></iconify-icon>
                </button>
                <div v-if="outdatedOpen">
                    <StationCard
                        v-for="station in outdated"
                        :key="station.station_id"
                        :avg-pence="avgPence"
                        :lowest-price="lowestPrice"
                        :origin="origin"
                        :station="station"
                        class="mb-2"
                    />
                </div>
            </section>
        </template>

        <!-- Flat list for other sort modes -->
        <div v-else class="space-y-2">
            <StationCard
                v-for="station in stations"
                :key="station.station_id"
                :avg-pence="avgPence"
                :lowest-price="lowestPrice"
                :origin="origin"
                :station="station"
            />
        </div>
    </div>
</template>

<script setup>
import { computed, ref } from 'vue'
import StationCard from './StationCard.vue'

const props = defineProps({
    stations: { type: Array, required: true },
    currentSort: { type: String, default: 'reliable' },
    origin: { type: Object, default: null },
})

const reliable = computed(() => props.stations.filter(s => s.reliability === 'reliable'))
const stale = computed(() => props.stations.filter(s => s.reliability === 'stale'))
const outdated = computed(() => props.stations.filter(s => s.reliability === 'outdated'))

const outdatedOpen = ref(false)

const lowestPrice = computed(() => {
    if (!reliable.value.length && !props.stations.length) return null
    const pool = reliable.value.length ? reliable.value : props.stations
    return Math.min(...pool.map(s => s.price_pence))
})

const avgPence = computed(() => {
    const prices = props.stations.map(s => s.price_pence).filter(p => typeof p === 'number')
    if (!prices.length) return null
    return prices.reduce((a, b) => a + b, 0) / prices.length
})
</script>
