//
//  WorkbenchView.swift
//  Zyquo MLX
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//

import SwiftUI

/// The main workbench: 240pt translucent left navigator + contextual header
/// + section content (charter §4.2).
struct WorkbenchView: View {
    @State private var model = AppModel()

    var body: some View {
        HStack(spacing: 0) {
            SidebarView(model: model)
                .frame(width: ZyquoTheme.sidebarWidth)

            Rectangle()
                .fill(ZyquoTheme.border)
                .frame(width: ZyquoTheme.hairline)

            VStack(spacing: 0) {
                HeaderBar(model: model)
                    .frame(height: ZyquoTheme.headerHeight)

                Rectangle()
                    .fill(ZyquoTheme.border)
                    .frame(height: ZyquoTheme.hairline)

                sectionContent
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
            }
            .background(ZyquoTheme.background)
        }
        .frame(
            minWidth: ZyquoTheme.minWindowSize.width,
            minHeight: ZyquoTheme.minWindowSize.height)
        .task { await model.refresh() }
        .onReceive(NotificationCenter.default.publisher(for: .zyquoNavigate)) { note in
            if let section = note.object as? WorkbenchSection {
                model.selectedSection = section
            }
        }
    }

    @ViewBuilder
    private var sectionContent: some View {
        switch model.selectedSection {
        case .models: ModelsView(model: model)
        case .datasets: DatasetsView(model: model)
        case .train: TrainView(model: model)
        case .convert: ConvertView(model: model)
        case .playground: PlaygroundView(model: model)
        case .evaluate: EvaluateView(model: model)
        }
    }
}

// MARK: - Sidebar

struct SidebarView: View {
    @Bindable var model: AppModel

    var body: some View {
        VStack(alignment: .leading, spacing: 0) {
            // Wordmark
            HStack(spacing: ZyquoTheme.spacing8) {
                Image(systemName: "z.square.fill")
                    .font(.system(size: 22))
                    .foregroundStyle(ZyquoTheme.accent)
                Text("Zyquo MLX")
                    .font(ZyquoTheme.headlineFont)
                    .foregroundStyle(ZyquoTheme.textPrimary)
            }
            .padding(.horizontal, ZyquoTheme.spacing16)
            .padding(.top, ZyquoTheme.spacing20)
            .padding(.bottom, ZyquoTheme.spacing24)

            ForEach(WorkbenchSection.allCases) { section in
                SidebarRow(
                    section: section,
                    isSelected: model.selectedSection == section,
                    badge: badge(for: section)
                ) {
                    withAnimation(ZyquoTheme.quickAnimation) {
                        model.selectedSection = section
                    }
                }
            }

            Spacer()

            SidebarFooter(model: model)
        }
        .background(.ultraThinMaterial)
    }

    private func badge(for section: WorkbenchSection) -> String? {
        switch section {
        case .models: model.models.isEmpty ? nil : "\(model.models.count)"
        case .datasets: model.datasets.isEmpty ? nil : "\(model.datasets.count)"
        case .train: model.runs.isEmpty ? nil : "\(model.runs.count)"
        default: nil
        }
    }
}

private struct SidebarRow: View {
    let section: WorkbenchSection
    let isSelected: Bool
    let badge: String?
    let action: () -> Void

    @State private var isHovering = false

    var body: some View {
        Button(action: action) {
            HStack(spacing: ZyquoTheme.spacing12) {
                Image(systemName: section.icon)
                    .font(.system(size: 14, weight: .medium))
                    .foregroundStyle(isSelected ? ZyquoTheme.accent : ZyquoTheme.textSecondary)
                    .frame(width: 20)
                Text(section.title)
                    .font(ZyquoTheme.bodyFont.weight(isSelected ? .semibold : .regular))
                    .foregroundStyle(isSelected ? ZyquoTheme.textPrimary : ZyquoTheme.textSecondary)
                Spacer()
                if let badge {
                    Text(badge)
                        .font(ZyquoTheme.captionFont)
                        .foregroundStyle(ZyquoTheme.textTertiary)
                }
            }
            .padding(.horizontal, ZyquoTheme.spacing12)
            .padding(.vertical, ZyquoTheme.spacing8)
            .background(
                RoundedRectangle(cornerRadius: ZyquoTheme.radiusSmall)
                    .fill(
                        isSelected
                            ? ZyquoTheme.accentSubtle
                            : isHovering ? ZyquoTheme.surfaceSecondary : .clear)
            )
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .padding(.horizontal, ZyquoTheme.spacing8)
        .onHover { isHovering = $0 }
    }
}

private struct SidebarFooter: View {
    @Bindable var model: AppModel
    @Environment(\.openSettings) private var openSettings

    var body: some View {
        VStack(spacing: ZyquoTheme.spacing8) {
            Rectangle()
                .fill(ZyquoTheme.border)
                .frame(height: ZyquoTheme.hairline)

            HStack(spacing: ZyquoTheme.spacing8) {
                Button {
                    openSettings()
                } label: {
                    Image(systemName: "gearshape")
                        .font(.system(size: 13))
                        .foregroundStyle(ZyquoTheme.textSecondary)
                }
                .buttonStyle(.plain)
                .help("Settings")

                if model.activeJobCount > 0 {
                    HStack(spacing: ZyquoTheme.spacing4) {
                        ProgressView()
                            .controlSize(.small)
                        Text("\(model.activeJobCount)")
                            .font(ZyquoTheme.captionFont)
                            .foregroundStyle(ZyquoTheme.textSecondary)
                    }
                    .help("Active jobs")
                }

                Spacer()

                HStack(spacing: ZyquoTheme.spacing4) {
                    Circle()
                        .fill(memoryColor)
                        .frame(width: 7, height: 7)
                    Text(memoryLabel)
                        .font(ZyquoTheme.monoSmallFont)
                        .foregroundStyle(ZyquoTheme.textTertiary)
                }
                .help("GPU memory in use / unified memory")
            }
            .padding(.horizontal, ZyquoTheme.spacing16)
            .padding(.bottom, ZyquoTheme.spacing12)
        }
    }

    private var memoryLabel: String {
        let used = Double(model.memoryUsedBytes) / 1_073_741_824
        let total = Double(model.memoryTotalBytes) / 1_073_741_824
        return String(format: "%.1f / %.0f GB", used, total)
    }

    private var memoryColor: Color {
        let fraction = Double(model.memoryUsedBytes) / Double(max(1, model.memoryTotalBytes))
        if fraction > 0.75 { return ZyquoTheme.danger }
        if fraction > 0.5 { return ZyquoTheme.warning }
        return ZyquoTheme.success
    }
}

// MARK: - Header

struct HeaderBar: View {
    @Bindable var model: AppModel

    var body: some View {
        HStack(spacing: ZyquoTheme.spacing12) {
            Text(model.selectedSection.title)
                .font(ZyquoTheme.titleFont)
                .foregroundStyle(ZyquoTheme.textPrimary)

            Spacer()

            if model.activeJobCount > 0 {
                StatusPill(
                    text: "\(model.activeJobCount) active job\(model.activeJobCount > 1 ? "s" : "")",
                    color: ZyquoTheme.accent)
            }

            Button {
                Task { await model.refresh() }
            } label: {
                Image(systemName: "arrow.clockwise")
                    .font(.system(size: 12, weight: .medium))
                    .foregroundStyle(ZyquoTheme.textSecondary)
            }
            .buttonStyle(.plain)
            .help("Refresh library")
        }
        .padding(.horizontal, ZyquoTheme.spacing20)
        .background(ZyquoTheme.background)
    }
}