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

import SwiftUI

/// Settings window (charter §4.2): native tabs, 760×560.
/// Functional depth (HF token vault, compute limits) lands in Phase 6.
struct SettingsView: View {
    var body: some View {
        TabView {
            GeneralSettings()
                .tabItem { Label("General", systemImage: "gearshape") }
            ComputeSettings()
                .tabItem { Label("Compute", systemImage: "cpu") }
            PythonSettings()
                .tabItem { Label("Python", systemImage: "terminal") }
            StorageSettings()
                .tabItem { Label("Storage", systemImage: "internaldrive") }
            HuggingFaceSettings()
                .tabItem { Label("Hugging Face", systemImage: "key") }
            AppearanceSettings()
                .tabItem { Label("Appearance", systemImage: "paintpalette") }
        }
        .frame(width: 760, height: 560)
    }
}

private struct GeneralSettings: View {
    var body: some View {
        Form {
            LabeledContent("Models") {
                PathLabel(url: PersistenceService.modelsDirectory)
            }
            LabeledContent("Datasets") {
                PathLabel(url: PersistenceService.datasetsDirectory)
            }
            LabeledContent("Training runs") {
                PathLabel(url: PersistenceService.runsDirectory)
            }
        }
        .formStyle(.grouped)
    }
}

private struct ComputeSettings: View {
    var body: some View {
        Form {
            Section("GPU") {
                LabeledContent("Unified memory") {
                    Text(ByteCountFormatter.string(
                        fromByteCount: MemoryAdvisor.physicalMemory, countStyle: .memory))
                }
                LabeledContent("Recommended working set") {
                    Text(ByteCountFormatter.string(
                        fromByteCount: MemoryAdvisor.recommendedWorkingSet, countStyle: .memory))
                }
            }
        }
        .formStyle(.grouped)
    }
}

private struct PythonSettings: View {
    @State private var status = "Checking…"

    var body: some View {
        Form {
            Section("Environment") {
                LabeledContent("Status") { Text(status) }
                LabeledContent("Location") {
                    PathLabel(url: PersistenceService.pythonDirectory)
                }
                LabeledContent("Pinned packages") {
                    Text(PythonEnvironment.corePins.joined(separator: ", "))
                        .font(ZyquoTheme.monoSmallFont)
                }
            }
        }
        .formStyle(.grouped)
        .task {
            status = await PythonEnvironment.shared.isProvisioned
                ? "Ready (Python \(PythonEnvironment.pythonVersion))"
                : "Not provisioned — installs automatically on first use"
        }
    }
}

private struct StorageSettings: View {
    @State private var usage: [(String, Int64)] = []

    var body: some View {
        Form {
            Section("Disk usage") {
                ForEach(usage, id: \.0) { name, bytes in
                    LabeledContent(name) {
                        Text(ByteCountFormatter.string(fromByteCount: bytes, countStyle: .file))
                    }
                }
            }
        }
        .formStyle(.grouped)
        .task {
            usage = [
                ("Models", directorySize(PersistenceService.modelsDirectory)),
                ("Datasets", directorySize(PersistenceService.datasetsDirectory)),
                ("Runs", directorySize(PersistenceService.runsDirectory)),
                ("Python", directorySize(PersistenceService.pythonDirectory)),
            ]
        }
    }

    private func directorySize(_ url: URL) -> Int64 {
        let fm = FileManager.default
        guard let files = try? fm.subpathsOfDirectory(atPath: url.path) else { return 0 }
        return files.reduce(Int64(0)) { total, path in
            let size = (try? url.appendingPathComponent(path)
                .resourceValues(forKeys: [.fileSizeKey]))?.fileSize ?? 0
            return total + Int64(size)
        }
    }
}

private struct HuggingFaceSettings: View {
    @State private var token = HFTokenStore.token ?? ""
    @State private var saved = false

    var body: some View {
        Form {
            Section("Access token") {
                SecureField("hf_…", text: $token)
                Text("Stored in your login Keychain — used for gated models and higher rate limits.")
                    .font(ZyquoTheme.captionFont)
                    .foregroundStyle(ZyquoTheme.textSecondary)
                HStack {
                    Button("Save") {
                        HFTokenStore.save(token.trimmingCharacters(in: .whitespaces))
                        saved = true
                    }
                    if saved {
                        Text("Saved ✓")
                            .font(ZyquoTheme.captionFont)
                            .foregroundStyle(ZyquoTheme.success)
                    }
                }
            }
        }
        .formStyle(.grouped)
    }
}

private struct AppearanceSettings: View {
    @AppStorage("appearance") private var appearance = "system"

    var body: some View {
        Form {
            Picker("Appearance", selection: $appearance) {
                Text("System").tag("system")
                Text("Light").tag("light")
                Text("Dark").tag("dark")
            }
            .pickerStyle(.inline)
        }
        .formStyle(.grouped)
    }
}

private struct PathLabel: View {
    let url: URL

    var body: some View {
        HStack {
            Text(url.path.replacingOccurrences(of: NSHomeDirectory(), with: "~"))
                .font(ZyquoTheme.monoSmallFont)
                .foregroundStyle(ZyquoTheme.textSecondary)
                .lineLimit(1)
                .truncationMode(.middle)
            Button {
                NSWorkspace.shared.activateFileViewerSelecting([url])
            } label: {
                Image(systemName: "arrow.right.circle")
            }
            .buttonStyle(.plain)
            .help("Reveal in Finder")
        }
    }
}