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

import SwiftUI

/// Centered header chip: model name + quant badge. Click → switcher popover
/// listing downloaded models with RAM verdicts; switching shows inline
/// progress in the chip. Morphs smoothly between unloaded/loading/ready.
struct ModelChipView: View {
    let conversation: Conversation
    @Environment(AppModel.self) private var app
    @State private var showSwitcher = false

    var body: some View {
        Button {
            showSwitcher.toggle()
        } label: {
            HStack(spacing: ZyquoTheme.Spacing.xs) {
                switch app.engineState {
                case .loading(let repoID):
                    ProgressView()
                        .controlSize(.mini)
                    Text("Loading \(shortModelName(repoID))…")
                        .font(ZyquoTheme.caption)
                        .foregroundStyle(ZyquoTheme.textSecondary)
                case .ready(let repoID), .generating(let repoID):
                    Circle()
                        .fill(ZyquoTheme.success)
                        .frame(width: 7, height: 7)
                    Text(chipTitle(repoID))
                        .font(ZyquoTheme.bodyEmphasis)
                        .foregroundStyle(ZyquoTheme.textPrimary)
                case .unloaded:
                    Circle()
                        .fill(ZyquoTheme.textTertiary)
                        .frame(width: 7, height: 7)
                    Text(app.store.models.isEmpty ? "No model" : "Choose a model")
                        .font(ZyquoTheme.body)
                        .foregroundStyle(ZyquoTheme.textSecondary)
                }
                Image(systemName: "chevron.down")
                    .font(.system(size: 9, weight: .semibold))
                    .foregroundStyle(ZyquoTheme.textTertiary)
            }
            .padding(.horizontal, ZyquoTheme.Spacing.s)
            .padding(.vertical, 5)
            .background(ZyquoTheme.surface, in: Capsule())
            .overlay(Capsule().stroke(ZyquoTheme.border, lineWidth: ZyquoTheme.hairline))
            .animation(.snappy(duration: 0.2), value: app.engineState)
        }
        .buttonStyle(PressableButtonStyle())
        .popover(isPresented: $showSwitcher, arrowEdge: .bottom) {
            ModelSwitcherPopover(conversation: conversation)
        }
        .onReceive(NotificationCenter.default.publisher(for: .zyquoOpenModelSwitcher)) { _ in
            showSwitcher = true
        }
    }

    private func chipTitle(_ repoID: String) -> String {
        let name = shortModelName(repoID)
        if let quant = app.store.model(for: repoID)?.quantization {
            let base = name.replacingOccurrences(of: "-\(quant)", with: "")
            return "\(base) · \(quant)"
        }
        return name
    }
}

/// Popover listing downloaded models with RAM verdicts.
struct ModelSwitcherPopover: View {
    let conversation: Conversation
    @Environment(AppModel.self) private var app
    @Environment(\.dismiss) private var dismiss

    var body: some View {
        VStack(alignment: .leading, spacing: 0) {
            Text("Switch model")
                .font(ZyquoTheme.caption)
                .foregroundStyle(ZyquoTheme.textSecondary)
                .padding(ZyquoTheme.Spacing.s)

            if app.store.models.isEmpty {
                VStack(spacing: ZyquoTheme.Spacing.xs) {
                    Text("No models downloaded yet.")
                        .font(ZyquoTheme.body)
                        .foregroundStyle(ZyquoTheme.textSecondary)
                    Button("Open Library") {
                        app.route = .library
                        dismiss()
                    }
                    .buttonStyle(.borderedProminent)
                    .tint(ZyquoTheme.accent)
                }
                .padding(ZyquoTheme.Spacing.m)
            } else {
                ScrollView {
                    VStack(spacing: 2) {
                        ForEach(app.store.models) { model in
                            row(model)
                        }
                    }
                    .padding(.horizontal, ZyquoTheme.Spacing.xs)
                    .padding(.bottom, ZyquoTheme.Spacing.xs)
                }
                .frame(maxHeight: 320)

                if app.loadedModelID != nil {
                    Rectangle().fill(ZyquoTheme.border).frame(height: ZyquoTheme.hairline)
                    Button {
                        Task { await app.unloadModel() }
                        dismiss()
                    } label: {
                        Label("Unload model", systemImage: "eject")
                            .font(ZyquoTheme.body)
                            .foregroundStyle(ZyquoTheme.textSecondary)
                    }
                    .buttonStyle(.plain)
                    .padding(ZyquoTheme.Spacing.s)
                }
            }
        }
        .frame(width: 320)
    }

    @ViewBuilder
    private func row(_ model: LocalModel) -> some View {
        let verdict = MemoryAdvisor.verdict(weightsBytes: model.sizeBytes)
        let isLoaded = app.loadedModelID == model.repoID
        Button {
            guard !isLoaded, verdict != .tooLarge else { return }
            var c = conversation
            c.modelID = model.repoID
            app.update(c, touch: false)
            Task { await app.loadModel(repoID: model.repoID) }
            dismiss()
        } label: {
            HStack(spacing: ZyquoTheme.Spacing.xs) {
                VStack(alignment: .leading, spacing: 1) {
                    Text(model.name)
                        .font(ZyquoTheme.body)
                        .foregroundStyle(ZyquoTheme.textPrimary)
                        .lineLimit(1)
                    Text("\(model.organization) · \(formatBytes(model.sizeBytes))")
                        .font(ZyquoTheme.caption)
                        .foregroundStyle(ZyquoTheme.textTertiary)
                }
                Spacer()
                if isLoaded {
                    Image(systemName: "checkmark.circle.fill")
                        .foregroundStyle(ZyquoTheme.accent)
                } else {
                    VerdictBadge(verdict: verdict)
                }
            }
            .padding(ZyquoTheme.Spacing.xs)
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .hoverHighlight()
        .disabled(verdict == .tooLarge && !isLoaded)
    }
}