// AnimationPanelView.swift
// Combined animation panel: transport bar + Dope Sheet / Graph Editor toggle.
// Designed to slot into the bottom of any workspace layout.

import SwiftUI

struct AnimationPanelView: View {
    let animSystem: AnimationSystem
    @State private var player: AnimationPlayer?
    @State private var showGraphEditor = false

    var body: some View {
        VStack(spacing: 0) {
            // ── Editor switcher + Toolbar ──
            editorToolbar

            Divider().background(Color.white.opacity(0.1))

            // ── Dope Sheet or Graph Editor ──
            Group {
                if showGraphEditor {
                    GraphEditorView(animSystem: animSystem)
                } else {
                    DopeSheetView(
                        animSystem: animSystem,
                        player: player ?? AnimationPlayer(system: animSystem)
                    )
                }
            }
            .frame(maxWidth: .infinity, maxHeight: .infinity)

            Divider().background(Color.white.opacity(0.1))

            // ── Transport controls ──
            transportBar
        }
        .background(Color(red: 0.15, green: 0.15, blue: 0.15))
        .onAppear {
            if player == nil {
                player = AnimationPlayer(system: animSystem)
            }
        }
    }

    // MARK: - Editor toolbar (matches Blender's editor type selector)

    private var editorToolbar: some View {
        HStack(spacing: 8) {
            // Editor type switcher
            Picker("Editor", selection: $showGraphEditor) {
                Label("Dope Sheet", systemImage: "rectangle.split.3x1")
                    .tag(false)
                Label("Graph Editor", systemImage: "chart.xyaxis.line")
                    .tag(true)
            }
            .pickerStyle(.segmented)
            .frame(width: 220)

            Divider().frame(height: 16)

            if let action = animSystem.activeAction {
                // Action name
                HStack(spacing: 4) {
                    Image(systemName: "film")
                        .font(.system(size: 10))
                        .foregroundStyle(.orange)
                    Text(action.name)
                        .font(.system(size: 11, weight: .medium))
                }
            }

            Spacer()

            // Interpolation mode for selected keyframes
            Menu {
                ForEach(KeyframeInterpolation.allCases) { interp in
                    Button {
                        setSelectedInterpolation(interp)
                    } label: {
                        Text(interp.rawValue)
                    }
                }
            } label: {
                Label("Interpolation", systemImage: "point.topleft.down.to.point.bottomright.curvepath")
                    .font(.system(size: 10))
            }

            // Handle type for selected keyframes
            Menu {
                ForEach(HandleType.allCases) { ht in
                    Button {
                        setSelectedHandleType(ht)
                    } label: {
                        Text(ht.rawValue)
                    }
                }
            } label: {
                Label("Handles", systemImage: "point.bottomleft.forward.to.arrowtriangle.uturn.scurvepath")
                    .font(.system(size: 10))
            }

            // Insert keyframe
            Button {
                insertKeyframeAtCurrent()
            } label: {
                Image(systemName: "diamond.fill")
                    .font(.system(size: 10))
                    .foregroundStyle(.yellow)
            }
        }
        .padding(.horizontal, 12)
        .padding(.vertical, 4)
        .background(Color(red: 0.17, green: 0.17, blue: 0.17))
    }

    // MARK: - Transport controls (Blender style)

    private var transportBar: some View {
        HStack(spacing: 0) {
            // Left: frame range
            HStack(spacing: 4) {
                Text("Start:")
                    .font(.system(size: 9))
                    .foregroundStyle(.secondary)
                Text(String(format: "%.0f", animSystem.frameStart))
                    .font(.system(size: 10, design: .monospaced))
                    .frame(width: 36)
                    .padding(.horizontal, 4)
                    .padding(.vertical, 2)
                    .background(Color.white.opacity(0.06), in: RoundedRectangle(cornerRadius: 3))

                Text("End:")
                    .font(.system(size: 9))
                    .foregroundStyle(.secondary)
                Text(String(format: "%.0f", animSystem.frameEnd))
                    .font(.system(size: 10, design: .monospaced))
                    .frame(width: 36)
                    .padding(.horizontal, 4)
                    .padding(.vertical, 2)
                    .background(Color.white.opacity(0.06), in: RoundedRectangle(cornerRadius: 3))
            }
            .padding(.horizontal, 12)

            Spacer()

            // Center: transport buttons
            HStack(spacing: 2) {
                transportButton(icon: "backward.end.fill") { player?.jumpToStart() }
                transportButton(icon: "chevron.backward") { player?.previousKeyframe() }
                transportButton(icon: "backward.frame.fill") { player?.stepBackward() }

                // Play/Pause (larger, highlighted)
                Button { player?.togglePlayback() } label: {
                    Image(systemName: animSystem.isPlaying ? "pause.fill" : "play.fill")
                        .font(.system(size: 14))
                        .frame(width: 36, height: 28)
                        .background(
                            animSystem.isPlaying
                                ? Color(red: 0.30, green: 0.55, blue: 0.95).opacity(0.3)
                                : Color.white.opacity(0.08),
                            in: RoundedRectangle(cornerRadius: 4)
                        )
                        .foregroundStyle(animSystem.isPlaying ? .blue : .primary)
                }
                .buttonStyle(.plain)

                transportButton(icon: "forward.frame.fill") { player?.stepForward() }
                transportButton(icon: "chevron.forward") { player?.nextKeyframe() }
                transportButton(icon: "forward.end.fill") { player?.jumpToEnd() }
            }

            Spacer()

            // Right: current frame + FPS
            HStack(spacing: 8) {
                // Current frame
                HStack(spacing: 2) {
                    Image(systemName: "film")
                        .font(.system(size: 9))
                        .foregroundStyle(.secondary)
                    Text(String(format: "%.0f", animSystem.currentFrame))
                        .font(.system(size: 11, weight: .bold, design: .monospaced))
                        .foregroundStyle(Color(red: 0.30, green: 0.55, blue: 0.95))
                        .frame(width: 40)
                }

                Divider().frame(height: 16)

                // FPS
                HStack(spacing: 2) {
                    Text("\(Int(animSystem.fps))")
                        .font(.system(size: 10, design: .monospaced))
                    Text("fps")
                        .font(.system(size: 9))
                        .foregroundStyle(.secondary)
                }

                // Loop toggle
                Button {
                    animSystem.isLooping.toggle()
                } label: {
                    Image(systemName: "repeat")
                        .font(.system(size: 10))
                        .foregroundStyle(animSystem.isLooping ? .orange : .secondary)
                }
                .buttonStyle(.plain)
            }
            .padding(.horizontal, 12)
        }
        .padding(.vertical, 6)
        .background(Color(red: 0.14, green: 0.14, blue: 0.14))
    }

    private func transportButton(icon: String, action: @escaping () -> Void) -> some View {
        Button(action: action) {
            Image(systemName: icon)
                .font(.system(size: 10))
                .frame(width: 28, height: 28)
                .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .foregroundStyle(.secondary)
    }

    // MARK: - Actions

    private func setSelectedInterpolation(_ interp: KeyframeInterpolation) {
        guard let action = animSystem.activeAction else { return }
        for track in action.tracks {
            for kf in track.keyframes where kf.isSelected {
                kf.interpolation = interp
            }
        }
    }

    private func setSelectedHandleType(_ ht: HandleType) {
        guard let action = animSystem.activeAction else { return }
        for track in action.tracks {
            for kf in track.keyframes where kf.isSelected {
                kf.handleType = ht
            }
            track.recomputeAutoHandles()
        }
    }

    private func insertKeyframeAtCurrent() {
        guard let action = animSystem.activeAction else { return }
        let frame = animSystem.currentFrame
        for track in action.tracks {
            let currentVal = track.evaluate(at: frame)
            track.insertKeyframe(frame: frame, value: currentVal)
        }
    }
}