// Auteur : Simon-Pierre Boucher — contact@spboucher.ai
// AgentChatView.swift — KA Agent natif plein volet : le même assistant IA que
// sur les sites (API centrale api-ka, site « groupe-ka »), flux SSE token par
// token + puces d'outils. Adapté de l'app iOS KA (AgentChatView.swift).
import SwiftUI

struct AgentMessage: Identifiable, Equatable {
    let id = UUID()
    var role: String            // user / assistant / tool
    var content: String
}

@MainActor
final class AgentChat: ObservableObject {
    @Published var messages: [AgentMessage] = []
    @Published var busy = false
    var site: String = "groupe-ka"

    func send(_ text: String) {
        let q = text.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !q.isEmpty, !busy else { return }
        messages.append(AgentMessage(role: "user", content: q))
        messages.append(AgentMessage(role: "assistant", content: ""))
        busy = true
        let history = messages
            .filter { $0.role == "user" || ($0.role == "assistant" && !$0.content.isEmpty) }
            .suffix(16)
            .map { ["role": $0.role, "content": $0.content] }

        Task {
            do {
                for try await event in AgentService.stream(site: site, messages: Array(history)) {
                    switch event.kind {
                    case .delta(let t):
                        if let i = messages.lastIndex(where: { $0.role == "assistant" }) {
                            messages[i].content += t
                        }
                    case .tool(let name):
                        // insérer la puce outil AVANT la bulle assistante en cours
                        if let i = messages.lastIndex(where: { $0.role == "assistant" }) {
                            messages.insert(AgentMessage(role: "tool", content: name.replacingOccurrences(of: "_", with: " ")), at: i)
                        }
                    case .error(let m):
                        if let i = messages.lastIndex(where: { $0.role == "assistant" }), messages[i].content.isEmpty {
                            messages[i].content = "Désolé, une erreur est survenue (\(m)). Réessayez."
                        }
                    case .done: break
                    }
                }
            } catch {
                if let i = messages.lastIndex(where: { $0.role == "assistant" }), messages[i].content.isEmpty {
                    messages[i].content = "Impossible de joindre KA Agent — vérifiez votre connexion."
                }
            }
            busy = false
        }
    }
}

struct AgentChatView: View {
    @StateObject private var chat = AgentChat()
    @State private var input = ""
    @Environment(\.colorScheme) private var scheme
    @FocusState private var focused: Bool

    var body: some View {
        VStack(spacing: 0) {
            header
            Divider().opacity(0.4)
            ScrollViewReader { proxy in
                ScrollView {
                    LazyVStack(alignment: .leading, spacing: 10) {
                        hello
                        ForEach(chat.messages) { m in
                            bubble(m).id(m.id)
                        }
                    }
                    .padding(16)
                    .frame(maxWidth: 780)
                    .frame(maxWidth: .infinity)
                }
                .onChange(of: chat.messages.last?.content) {
                    if let last = chat.messages.last { proxy.scrollTo(last.id, anchor: .bottom) }
                }
            }
            inputBar
        }
        .background(KATheme.paper(scheme))
        .onAppear { focused = true }
    }

    private var header: some View {
        HStack(spacing: 6) {
            Text("KA").font(.system(.headline, design: .rounded).weight(.bold))
            Text("Agent")
                .font(.system(.subheadline, design: .rounded).weight(.bold))
                .foregroundStyle(KATheme.lime)
                .padding(.horizontal, 7).padding(.vertical, 2)
                .background(KATheme.inkLight, in: RoundedRectangle(cornerRadius: 6))
                .rotationEffect(.degrees(-2))
            Text("· l'IA de l'écosystème, branchée sur les vraies données")
                .font(.caption).foregroundStyle(.secondary)
            Spacer()
            if !chat.messages.isEmpty {
                Button {
                    chat.messages = []
                } label: {
                    Label("Nouvelle conversation", systemImage: "square.and.pencil")
                        .font(.caption)
                }
                .disabled(chat.busy)
            }
        }
        .padding(.horizontal, 16).padding(.vertical, 10)
    }

    private var hello: some View {
        Group {
            if chat.messages.isEmpty {
                VStack(alignment: .leading, spacing: 10) {
                    Text("👋 Je suis KA Agent.")
                        .font(.headline)
                    Text("Posez-moi n'importe quelle question sur l'écosystème Groupe KA et ses données : logements, propriétés, autos, emplois, prix d'épicerie, restos, sorties, créateurs, statistiques…")
                        .font(.subheadline).foregroundStyle(.secondary)
                    FlowSuggestions { s in
                        chat.send(s)
                        input = ""
                    }
                }
                .padding(16)
                .frame(maxWidth: .infinity, alignment: .leading)
                .kaCard()
            }
        }
    }

    @ViewBuilder
    private func bubble(_ m: AgentMessage) -> some View {
        switch m.role {
        case "user":
            HStack {
                Spacer(minLength: 60)
                Text(m.content)
                    .textSelection(.enabled)
                    .padding(.horizontal, 13).padding(.vertical, 9)
                    .background(KATheme.lime, in: RoundedRectangle(cornerRadius: 12, style: .continuous))
                    .overlay(RoundedRectangle(cornerRadius: 12, style: .continuous)
                        .strokeBorder(KATheme.inkLight.opacity(0.6), lineWidth: 1))
                    .foregroundStyle(KATheme.inkLight)
            }
        case "tool":
            Label(m.content, systemImage: "magnifyingglass")
                .font(.system(.caption2, design: .monospaced).weight(.bold))
                .textCase(.uppercase)
                .padding(.horizontal, 10).padding(.vertical, 5)
                .overlay(Capsule().strokeBorder(style: StrokeStyle(lineWidth: 1, dash: [3])))
                .foregroundStyle(.secondary)
        default:
            Group {
                if m.content.isEmpty {
                    ProgressView().controlSize(.small).padding(10)
                } else {
                    Text(LocalizedStringKey(m.content)) // rend **gras** et liens Markdown
                        .textSelection(.enabled)
                        .padding(.horizontal, 13).padding(.vertical, 9)
                        .kaCard()
                }
            }
            .frame(maxWidth: .infinity, alignment: .leading)
        }
    }

    private var inputBar: some View {
        HStack(spacing: 8) {
            TextField("Posez votre question…", text: $input, axis: .vertical)
                .textFieldStyle(.plain)
                .lineLimit(1...4)
                .padding(.horizontal, 13).padding(.vertical, 10)
                .background(KATheme.surface(scheme), in: RoundedRectangle(cornerRadius: 11, style: .continuous))
                .overlay(RoundedRectangle(cornerRadius: 11, style: .continuous)
                    .strokeBorder(.primary.opacity(0.35), lineWidth: 1.2))
                .focused($focused)
                .onSubmit { chat.send(input); input = "" }
            Button {
                chat.send(input); input = ""
            } label: {
                Image(systemName: "arrow.up")
                    .font(.headline)
                    .frame(width: 38, height: 38)
                    .background(KATheme.inkLight, in: Circle())
                    .foregroundStyle(KATheme.lime)
            }
            .buttonStyle(.plain)
            .disabled(chat.busy || input.trimmingCharacters(in: .whitespaces).isEmpty)
            .accessibilityLabel("Envoyer")
        }
        .padding(12)
        .frame(maxWidth: 780)
        .frame(maxWidth: .infinity)
        .background(.bar)
    }
}

private struct FlowSuggestions: View {
    let action: (String) -> Void
    private let ideas = ["Combien de logements à louer ?", "Un resto italien à Montréal", "Les sorties gratuites ce week-end", "C'est quoi le Groupe KA ?"]
    var body: some View {
        VStack(alignment: .leading, spacing: 6) {
            ForEach(ideas, id: \.self) { s in
                Button { action(s) } label: {
                    Text(s).font(.caption.weight(.semibold))
                        .padding(.horizontal, 11).padding(.vertical, 7)
                        .background(.quaternary, in: Capsule())
                }
                .buttonStyle(.plain)
            }
        }
    }
}