import SwiftUI

/// The library's list presentation. Carries everything `BookmarkRow` carried —
/// unread state, excerpt, tags, podcast affordance, reading progress — in the
/// paper vocabulary. The favicon becomes the color chip, so the same swatch
/// that identifies a card identifies its row.
struct LibraryListRow: View {
    let bookmark: Bookmark
    var readingProgress: Double = 0
    var onPodcast: (() -> Void)? = nil

    @State private var podcastTapCount = 0
    @State private var podcastCached = false

    private var item: LibraryItem { LibraryItem(bookmark: bookmark) }

    /// Compact, static relative date ("6 min ago"). Using a formatter instead of
    /// `Text(_, style: .relative)` avoids the live per-second ticking timer.
    private static let relativeFormatter: RelativeDateTimeFormatter = {
        let f = RelativeDateTimeFormatter()
        f.unitsStyle = .abbreviated
        f.dateTimeStyle = .named
        return f
    }()

    var body: some View {
        HStack(alignment: .top, spacing: 12) {
            RoundedRectangle(cornerRadius: 3)
                .fill(item.swatch)
                .frame(width: 34, height: 46)
                .overlay(alignment: .topLeading) {
                    if bookmark.unread {
                        // Ink, not blue: the palette is the only color the
                        // library spends, and an accent dot would compete with
                        // the chip it sits on.
                        Circle()
                            .fill(Paper.ink)
                            .frame(width: 10, height: 10)
                            .overlay(Circle().stroke(Paper.sheet, lineWidth: 2))
                            .offset(x: -4, y: -4)
                    }
                }

            VStack(alignment: .leading, spacing: 5) {
                Text(item.listDisplay)
                    .font(.system(size: 21, design: .serif))
                    .foregroundStyle(Paper.ink)
                    .lineLimit(2)
                    .fixedSize(horizontal: false, vertical: true)

                HStack(spacing: 5) {
                    Text(item.source)
                    Text("·")
                    Text(Self.relativeFormatter.localizedString(
                        for: bookmark.dateAdded, relativeTo: Date()
                    ))
                }
                .font(.system(size: 15, design: .monospaced))
                .foregroundStyle(Paper.ink.opacity(0.45))
                .lineLimit(1)

                if let excerpt = rowExcerpt {
                    Text(excerpt.text)
                        .font(.system(size: 18, design: .serif))
                        .italic(excerpt.isAI)
                        .foregroundStyle(Paper.ink.opacity(0.6))
                        .lineLimit(2)
                }

                if !effectiveTags.isEmpty {
                    tagRow
                }
            }

            Spacer(minLength: 6)

            if let onPodcast {
                Button {
                    podcastTapCount += 1
                    onPodcast()
                } label: {
                    Image(systemName: podcastCached ? "headphones.circle.fill" : "headphones.circle")
                        .font(.system(size: 25.5, weight: .light))
                        .foregroundStyle(Paper.ink.opacity(podcastCached ? 0.75 : 0.3))
                }
                .buttonStyle(.plain)
                .sensoryFeedback(.impact(weight: .medium), trigger: podcastTapCount)
            }
        }
        .padding(.vertical, 14)
        .contentShape(Rectangle())
        .overlay(alignment: .bottom) {
            if readingProgress > 0.02 {
                GeometryReader { geo in
                    ZStack(alignment: .leading) {
                        Rectangle().fill(Paper.ink.opacity(0.1))
                        Rectangle()
                            .fill(Paper.ink.opacity(0.5))
                            .frame(width: geo.size.width * min(readingProgress, 1))
                    }
                }
                .frame(height: 2)
            }
        }
        .task(id: bookmark.url) {
            // Stat the podcast cache off the render path: once per appearance
            // (and when the URL changes), not on every `body` recomputation.
            let path = ClaudeService.cachedPodcastURL(for: bookmark.url).path
            podcastCached = await Task.detached { FileManager.default.fileExists(atPath: path) }.value
        }
    }

    /// Tags wrap onto up to two lines rather than scrolling sideways. At the
    /// scaled-up type a horizontal strip clipped its third chip mid-word, which
    /// read as broken text; wrapping shows whole tags or none.
    private var tagRow: some View {
        FlowLayout(spacing: 5, lineSpacing: 5, maxRows: 2) {
            ForEach(effectiveTags, id: \.self) { tag in
                Text(tag)
                    .font(.system(size: 15, design: .monospaced))
                    .foregroundStyle(Paper.ink.opacity(0.55))
                    .lineLimit(1)
                    .padding(.horizontal, 8)
                    .padding(.vertical, 3)
                    .overlay(
                        RoundedRectangle(cornerRadius: 4)
                            .stroke(Paper.rule.opacity(0.6), lineWidth: 0.6)
                    )
            }
        }
        .padding(.top, 1)
    }

    /// Excerpt shown under the title: prefer the AI summary (italic), else the
    /// page's scraped description / user note. nil hides the line entirely.
    private var rowExcerpt: (text: String, isAI: Bool)? {
        if let s = bookmark.aiSummary?.trimmingCharacters(in: .whitespacesAndNewlines), !s.isEmpty {
            return (s, true)
        }
        if let e = bookmark.contentExcerpt {
            return (e, false)
        }
        return nil
    }

    private var effectiveTags: [String] {
        let base = bookmark.tagNames
        let ai = bookmark.aiTags ?? []
        let extra = ai.filter { !base.contains($0) }.prefix(3)
        return (base + extra).prefix(6).map { $0 }
    }
}