//
//  ConsoleView.swift
//  Metrika
//
//  Author:  Simon-Pierre Boucher
//  Contact: contact@spboucher.ai
//  Copyright © 2026 Simon-Pierre Boucher. All rights reserved.
//

import SwiftUI

/// Command console: scrollback of executed commands with their rendered
/// output, plus an input line with ↑/↓ history recall (CLAUDE.md §7).
struct ConsoleView: View {
    @Environment(SessionModel.self) private var model
    @State private var input = ""
    @State private var historyCursor: Int?
    @FocusState private var inputFocused: Bool

    var body: some View {
        VStack(spacing: 0) {
            ScrollViewReader { proxy in
                ScrollView {
                    LazyVStack(alignment: .leading, spacing: 10) {
                        ForEach(model.entries) { entry in
                            VStack(alignment: .leading, spacing: 2) {
                                if !entry.command.isEmpty {
                                    Text(". \(entry.command)")
                                        .foregroundStyle(.secondary)
                                }
                                if !entry.output.isEmpty {
                                    Text(entry.output)
                                        .foregroundStyle(
                                            entry.isError ? Color.red : Color.primary
                                        )
                                        .textSelection(.enabled)
                                }
                            }
                            .id(entry.id)
                        }
                    }
                    .padding(12)
                    .frame(maxWidth: .infinity, alignment: .leading)
                }
                .onChange(of: model.entries) {
                    if let last = model.entries.last {
                        proxy.scrollTo(last.id, anchor: .bottom)
                    }
                }
            }

            Divider()

            HStack(spacing: 8) {
                Text(".")
                    .foregroundStyle(.secondary)
                TextField("Type a command — e.g. use sales.parquet", text: $input)
                    .textFieldStyle(.plain)
                    .focused($inputFocused)
                    .onSubmit(submit)
                    .onKeyPress(.upArrow) { recallHistory(step: -1) }
                    .onKeyPress(.downArrow) { recallHistory(step: 1) }
                if model.isRunning {
                    ProgressView()
                        .controlSize(.small)
                }
            }
            .padding(10)
        }
        .fontDesign(.monospaced)
        .font(.system(size: 12))
        .onAppear { inputFocused = true }
    }

    private func submit() {
        let command = input
        input = ""
        historyCursor = nil
        Task { await model.run(command) }
    }

    private func recallHistory(step: Int) -> KeyPress.Result {
        let history = model.history
        guard !history.isEmpty else { return .ignored }
        var cursor = historyCursor ?? history.count
        cursor = min(max(cursor + step, 0), history.count)
        historyCursor = cursor
        input = cursor < history.count ? history[cursor] : ""
        return .handled
    }
}

/// Sidebar: variables of the working dataset with type and missing count
/// (CLAUDE.md §7, pane 5).
struct VariablesSidebar: View {
    @Environment(SessionModel.self) private var model

    var body: some View {
        List {
            Section("Variables (\(model.observationCount) obs)") {
                ForEach(model.variables) { variable in
                    HStack {
                        Text(variable.name)
                            .fontDesign(.monospaced)
                        Spacer()
                        if variable.missingCount > 0 {
                            Text("\(variable.missingCount) mi")
                                .foregroundStyle(.orange)
                                .font(.caption)
                        }
                        Text(variable.type)
                            .foregroundStyle(.secondary)
                            .font(.caption)
                    }
                }
            }
        }
        .listStyle(.sidebar)
    }
}