// Author: Simon-Pierre Boucher — contact@spboucher.ai
//
// Navigation shell: runs in the sidebar, live dashboard in the detail pane.
import SwiftUI

enum SidebarItem: Hashable {
    case compare
    case datasets
    case run(UUID)
}

struct ContentView: View {
    @Environment(AppModel.self) private var app
    @State private var selection: SidebarItem?
    @State private var showNewRun = false

    var body: some View {
        NavigationSplitView {
            List(selection: $selection) {
                Section("Studio") {
                    Label("Comparer", systemImage: "chart.xyaxis.line")
                        .tag(SidebarItem.compare)
                    Label("Datasets", systemImage: "cylinder.split.1x2")
                        .tag(SidebarItem.datasets)
                }
                Section("Runs") {
                    ForEach(app.store.runs.sorted { $0.createdAt > $1.createdAt }) { run in
                        RunRow(run: run).tag(SidebarItem.run(run.id))
                    }
                }
            }
            .navigationSplitViewColumnWidth(min: 220, ideal: 260)
            .toolbar {
                ToolbarItem(placement: .primaryAction) {
                    Button {
                        showNewRun = true
                    } label: {
                        Label("Nouveau run", systemImage: "plus")
                    }
                    .disabled(app.forgeError != nil)
                }
            }
        } detail: {
            switch selection {
            case .compare:
                CompareView()
            case .datasets:
                DatasetsView()
            case .run(let id):
                if let run = app.store.runs.first(where: { $0.id == id }) {
                    RunDetailView(run: run)
                } else {
                    EmptyStateView()
                }
            case nil:
                EmptyStateView()
            }
        }
        .sheet(isPresented: $showNewRun) {
            NewRunSheet()
        }
    }
}

struct RunRow: View {
    let run: Run

    var body: some View {
        VStack(alignment: .leading, spacing: 2) {
            HStack {
                Text(run.name).font(.headline)
                Spacer()
                StateBadge(state: run.state)
            }
            HStack(spacing: 8) {
                Text("\(run.config.model.paramCount.formatted(.number.notation(.compactName))) params")
                if let loss = run.lastTrainLoss {
                    Text(String(format: "loss %.3f", loss))
                }
                if run.state.isActive {
                    ProgressView(value: run.progress).frame(width: 60)
                }
            }
            .font(.caption)
            .foregroundStyle(.secondary)
        }
        .padding(.vertical, 2)
    }
}

struct StateBadge: View {
    let state: RunState

    var color: Color {
        switch state {
        case .running, .launching: return .green
        case .finished: return .blue
        case .failed: return .red
        case .stopped: return .orange
        case .queued, .finishing: return .gray
        }
    }

    var body: some View {
        Text(state.rawValue)
            .font(.caption2.weight(.semibold))
            .padding(.horizontal, 6)
            .padding(.vertical, 2)
            .background(color.opacity(0.18), in: Capsule())
            .foregroundStyle(color)
    }
}

struct EmptyStateView: View {
    @Environment(AppModel.self) private var app

    var body: some View {
        VStack(spacing: 12) {
            Image(systemName: "flame")
                .font(.system(size: 48))
                .foregroundStyle(.orange)
            Text("Forge Studio").font(.largeTitle.weight(.semibold))
            if let device = app.forgeDevice {
                Label(device, systemImage: "cpu")
                    .foregroundStyle(.secondary)
            }
            if let error = app.forgeError {
                Label(error, systemImage: "exclamationmark.triangle")
                    .foregroundStyle(.red)
                SettingsLink { Text("Ouvrir les Réglages…") }
            } else {
                Text("Sélectionnez un run, ou créez-en un nouveau (+).")
                    .foregroundStyle(.secondary)
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}