//
//  DropZoneView.swift
//  MioIsland AirDrop Plugin
//
//  Click-to-choose zone at the center of the panel. Tapping anywhere
//  inside opens NSOpenPanel → user picks files → NSSharingService
//  fires the AirDrop chooser sheet.
//
//  Drag-and-drop was intentionally removed: macOS Dynamic Island
//  panels auto-collapse when the user clicks outside them, which
//  prevents the Cmd-Tab → Finder → grab file → drag back workflow.
//  Rather than fight the host's event routing, we commit to the
//  click-to-choose path which is rock-solid.
//

import SwiftUI

struct DropZoneView: View {
    @ObservedObject var state: AirDropState = .shared

    private static let lime = Color(
        red: 0xCA / 255.0,
        green: 0xFF / 255.0,
        blue: 0x00 / 255.0
    )
    private static let ink = Color.white

    var body: some View {
        ZStack {
            RoundedRectangle(cornerRadius: 14, style: .continuous)
                .fill(fillColor)

            RoundedRectangle(cornerRadius: 14, style: .continuous)
                .strokeBorder(strokeColor, lineWidth: 1)

            centerContent
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .contentShape(Rectangle())
        .onTapGesture {
            guard case .idle = state.phase else { return }
            state.chooseAndSend()
        }
        .animation(.easeInOut(duration: 0.25), value: state.phase)
    }

    // MARK: - Reactive styling

    private var fillColor: Color {
        switch state.phase {
        case .sent:          return Self.lime.opacity(0.14)
        case .showingPicker: return Color.white.opacity(0.08)
        case .error:         return Color.red.opacity(0.08)
        case .idle:          return Color.white.opacity(0.04)
        }
    }

    private var strokeColor: Color {
        switch state.phase {
        case .sent:          return Self.lime.opacity(0.9)
        case .showingPicker: return Self.lime.opacity(0.6)
        case .error:         return Color.red.opacity(0.7)
        case .idle:          return Color.white.opacity(0.18)
        }
    }

    // MARK: - Center content (icon + label)

    @ViewBuilder
    private var centerContent: some View {
        VStack(spacing: 8) {
            Image(systemName: iconName)
                .font(.system(size: 32, weight: .light))
                .foregroundColor(iconColor)

            Text(primaryText)
                .font(.system(size: 13, weight: .semibold))
                .foregroundColor(primaryColor)
                .multilineTextAlignment(.center)

            if let sub = secondaryText {
                Text(sub)
                    .font(.system(size: 11))
                    .foregroundColor(Self.ink.opacity(0.5))
            }
        }
        .padding(.horizontal, 20)
    }

    private var iconName: String {
        switch state.phase {
        case .sent:          return "checkmark.circle.fill"
        case .error:         return "exclamationmark.triangle.fill"
        case .showingPicker: return "airplayaudio"
        case .idle:          return "airplayaudio"
        }
    }

    private var iconColor: Color {
        switch state.phase {
        case .sent:          return Self.lime
        case .error:         return Color.red.opacity(0.8)
        case .showingPicker: return Self.ink.opacity(0.85)
        case .idle:          return Self.ink.opacity(0.7)
        }
    }

    private var primaryText: String {
        switch state.phase {
        case .sent(let n):   return L10n.sentCount(n)
        case .error(let m):  return m
        case .showingPicker: return L10n.opening
        case .idle:          return L10n.chooseFiles
        }
    }

    private var primaryColor: Color {
        switch state.phase {
        case .sent:  return Self.lime
        case .error: return Color.red.opacity(0.9)
        default:     return Self.ink.opacity(0.85)
        }
    }

    private var secondaryText: String? {
        guard case .idle = state.phase else { return nil }
        return L10n.clickToChoose
    }
}