//
//  SidebarView.swift
//  Zyquo Local
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//

import SwiftUI

/// Translucent 260 pt sidebar: wordmark, Chats (search + groups), Library
/// entry with live download badge, footer with settings + loaded-model chip.
struct SidebarView: View {
    @Environment(AppModel.self) private var app
    @Environment(\.openSettings) private var openSettings
    @State private var query = ""
    @State private var renamingID: UUID?
    @State private var renameText = ""
    @FocusState private var searchFocused: Bool

    var body: some View {
        VStack(spacing: 0) {
            wordmark
                .padding(.horizontal, ZyquoTheme.Spacing.m)
                .padding(.top, ZyquoTheme.Spacing.s)

            searchField
                .padding(.horizontal, ZyquoTheme.Spacing.s)
                .padding(.top, ZyquoTheme.Spacing.s)

            List(selection: selectionBinding) {
                Section {
                    newChatButton
                    libraryRow
                }
                ForEach(app.sidebarGroups(query: query)) { group in
                    Section(group.title) {
                        ForEach(group.conversations) { conversation in
                            conversationRow(conversation)
                                .tag(conversation.id)
                        }
                    }
                }
            }
            .scrollContentBackground(.hidden)
            .listStyle(.sidebar)

            footer
        }
        .background(.regularMaterial)
        .onReceive(NotificationCenter.default.publisher(for: .zyquoFocusSearch)) { _ in
            searchFocused = true
        }
    }

    private var selectionBinding: Binding<UUID?> {
        Binding(
            get: { app.route == .chat ? app.selectedConversationID : nil },
            set: { id in
                if let id {
                    app.selectedConversationID = id
                    app.route = .chat
                }
            }
        )
    }

    private var wordmark: some View {
        HStack(spacing: ZyquoTheme.Spacing.xs) {
            ZyquoGlyph(size: 18)
            Text("Zyquo Local")
                .font(ZyquoTheme.bodyEmphasis)
                .foregroundStyle(ZyquoTheme.textPrimary)
            Spacer()
        }
    }

    private var searchField: some View {
        HStack(spacing: ZyquoTheme.Spacing.xxs) {
            Image(systemName: "magnifyingglass")
                .font(.system(size: 11))
                .foregroundStyle(ZyquoTheme.textTertiary)
            TextField("Search chats", text: $query)
                .textFieldStyle(.plain)
                .font(ZyquoTheme.body)
                .focused($searchFocused)
        }
        .padding(.horizontal, ZyquoTheme.Spacing.xs)
        .padding(.vertical, 5)
        .background(ZyquoTheme.surfaceSecondary.opacity(0.6), in: RoundedRectangle(cornerRadius: ZyquoTheme.Radius.s))
        .overlay(
            RoundedRectangle(cornerRadius: ZyquoTheme.Radius.s)
                .stroke(ZyquoTheme.border, lineWidth: ZyquoTheme.hairline)
        )
    }

    private var newChatButton: some View {
        Button {
            app.newConversation()
        } label: {
            Label("New Chat", systemImage: "square.and.pencil")
                .font(ZyquoTheme.bodyEmphasis)
                .foregroundStyle(ZyquoTheme.accent)
        }
        .buttonStyle(.plain)
        .keyboardShortcut("n", modifiers: .command)
    }

    private var libraryRow: some View {
        Button {
            app.route = .library
        } label: {
            HStack {
                Label("Library", systemImage: "square.stack.3d.up")
                    .font(ZyquoTheme.body)
                Spacer()
                if app.downloads.activeCount > 0 {
                    HStack(spacing: ZyquoTheme.Spacing.xxs) {
                        ProgressView(value: app.downloads.overallFraction)
                            .progressViewStyle(.circular)
                            .controlSize(.mini)
                        Text("\(app.downloads.activeCount)")
                            .font(ZyquoTheme.caption)
                            .foregroundStyle(.white)
                            .padding(.horizontal, 6)
                            .padding(.vertical, 1)
                            .background(ZyquoTheme.accent, in: Capsule())
                    }
                }
            }
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .keyboardShortcut("l", modifiers: .command)
    }

    @ViewBuilder
    private func conversationRow(_ conversation: Conversation) -> some View {
        HStack(spacing: ZyquoTheme.Spacing.xs) {
            VStack(alignment: .leading, spacing: 2) {
                if renamingID == conversation.id {
                    TextField(
                        "Title", text: $renameText,
                        onCommit: {
                            var c = conversation
                            c.title = renameText.isEmpty ? conversation.title : renameText
                            app.update(c, touch: false)
                            renamingID = nil
                        }
                    )
                    .textFieldStyle(.plain)
                    .font(ZyquoTheme.body)
                } else {
                    Text(conversation.title)
                        .font(ZyquoTheme.body)
                        .lineLimit(1)
                }
                HStack(spacing: ZyquoTheme.Spacing.xxs) {
                    if let modelID = conversation.modelID {
                        Text(shortModelName(modelID))
                            .font(ZyquoTheme.caption)
                            .foregroundStyle(ZyquoTheme.textTertiary)
                            .lineLimit(1)
                    }
                    Text(conversation.updatedAt, format: .relative(presentation: .named))
                        .font(ZyquoTheme.caption)
                        .foregroundStyle(ZyquoTheme.textTertiary)
                }
            }
            Spacer(minLength: 0)
            if conversation.pinned {
                Image(systemName: "pin.fill")
                    .font(.system(size: 9))
                    .foregroundStyle(ZyquoTheme.textTertiary)
            }
        }
        .contextMenu {
            Button(conversation.pinned ? "Unpin" : "Pin") {
                app.togglePin(conversationID: conversation.id)
            }
            Button("Rename") {
                renameText = conversation.title
                renamingID = conversation.id
            }
            Divider()
            Button("Export as Markdown…") {
                ExportService.exportMarkdown(conversation)
            }
            Button("Export as PDF…") {
                ExportService.exportPDF(conversation)
            }
            Divider()
            Button("Delete", role: .destructive) {
                app.delete(conversationID: conversation.id)
            }
        }
    }

    private var footer: some View {
        VStack(spacing: 0) {
            Rectangle()
                .fill(ZyquoTheme.border)
                .frame(height: ZyquoTheme.hairline)
            HStack(spacing: ZyquoTheme.Spacing.xs) {
                Button {
                    openSettings()
                } label: {
                    Image(systemName: "gearshape")
                        .foregroundStyle(ZyquoTheme.textSecondary)
                }
                .buttonStyle(.plain)
                .help("Settings (⌘,)")

                Spacer()

                if let repoID = app.loadedModelID {
                    HStack(spacing: ZyquoTheme.Spacing.xxs) {
                        Circle()
                            .fill(memoryDotColor)
                            .frame(width: 7, height: 7)
                        Text(shortModelName(repoID))
                            .font(ZyquoTheme.caption)
                            .foregroundStyle(ZyquoTheme.textSecondary)
                            .lineLimit(1)
                        if app.liveMemoryBytes > 0 {
                            Text(formatBytes(Int64(app.liveMemoryBytes)))
                                .font(ZyquoTheme.caption)
                                .foregroundStyle(ZyquoTheme.textTertiary)
                        }
                    }
                    .padding(.horizontal, ZyquoTheme.Spacing.xs)
                    .padding(.vertical, 3)
                    .background(ZyquoTheme.surfaceSecondary.opacity(0.7), in: Capsule())
                    .help("Loaded model · active memory")
                } else {
                    Text("No model loaded")
                        .font(ZyquoTheme.caption)
                        .foregroundStyle(ZyquoTheme.textTertiary)
                }
            }
            .padding(.horizontal, ZyquoTheme.Spacing.m)
            .padding(.vertical, ZyquoTheme.Spacing.s)
        }
    }

    private var memoryDotColor: Color {
        let ram = Double(MemoryAdvisor.physicalMemoryBytes)
        let used = Double(app.liveMemoryBytes)
        if used < ram * 0.5 { return ZyquoTheme.success }
        if used < ram * 0.7 { return ZyquoTheme.warning }
        return ZyquoTheme.danger
    }
}

/// "Qwen3-8B-4bit" from "mlx-community/Qwen3-8B-4bit".
func shortModelName(_ repoID: String) -> String {
    repoID.split(separator: "/").last.map(String.init) ?? repoID
}

extension Notification.Name {
    static let zyquoFocusSearch = Notification.Name("zyquoFocusSearch")
    static let zyquoOpenModelSwitcher = Notification.Name("zyquoOpenModelSwitcher")
    static let zyquoExportConversation = Notification.Name("zyquoExportConversation")
}