//
//  HeaderView.swift
//  oAI
//
//  Header bar with provider, model, and stats
//
// SPDX-License-Identifier: AGPL-3.0-or-later
// Copyright (C) 2026 Rune Olsen
//
// This file is part of oAI.
//
// oAI is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// oAI is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General
// Public License for more details.
//
// You should have received a copy of the GNU Affero General Public
// License along with oAI. If not, see <https://www.gnu.org/licenses/>.


import SwiftUI

struct HeaderView: View {
    let provider: Settings.Provider
    let model: ModelInfo?
    let stats: SessionStats
    let onlineMode: Bool
    let mcpEnabled: Bool
    let mcpStatus: String?
    let onModelSelect: () -> Void
    let onProviderChange: (Settings.Provider) -> Void
    private let settings = SettingsService.shared
    private let registry = ProviderRegistry.shared
    private let gitSync = GitSyncService.shared

    var body: some View {
        HStack(spacing: 12) {
            // Provider picker dropdown — only shows configured providers
            Menu {
                ForEach(registry.configuredProviders, id: \.self) { p in
                    Button {
                        onProviderChange(p)
                    } label: {
                        HStack {
                            Image(systemName: p.iconName)
                            Text(p.displayName)
                            if p == provider {
                                Image(systemName: "checkmark")
                            }
                        }
                    }
                }
            } label: {
                HStack(spacing: 4) {
                    Image(systemName: provider.iconName)
                        .font(.system(size: settings.guiTextSize - 2))
                    Text(provider.displayName)
                        .font(.system(size: settings.guiTextSize - 2, weight: .medium))
                    Image(systemName: "chevron.up.chevron.down")
                        .font(.system(size: 8))
                        .opacity(0.7)
                }
                .foregroundColor(.white)
                .padding(.horizontal, 8)
                .padding(.vertical, 4)
                .background(Color.providerColor(provider))
                .cornerRadius(4)
            }
            .menuStyle(.borderlessButton)
            .fixedSize()
            .help("Switch provider")

            // Model info (clickable → model selector)
            Button(action: onModelSelect) {
                if let model = model {
                    HStack(spacing: 6) {
                        Text(model.name)
                            .font(.system(size: settings.guiTextSize, weight: .medium))
                            .foregroundColor(.oaiPrimary)

                        // Capability badges
                        HStack(spacing: 3) {
                            if model.capabilities.vision {
                                Image(systemName: "eye")
                                    .font(.system(size: 9))
                                    .foregroundColor(.oaiSecondary)
                            }
                            if model.capabilities.tools {
                                Image(systemName: "wrench")
                                    .font(.system(size: 9))
                                    .foregroundColor(.oaiSecondary)
                            }
                            if model.capabilities.online {
                                Image(systemName: "globe")
                                    .font(.system(size: 9))
                                    .foregroundColor(.oaiSecondary)
                            }
                            if model.capabilities.imageGeneration {
                                Image(systemName: "paintbrush")
                                    .font(.system(size: 9))
                                    .foregroundColor(.oaiSecondary)
                            }
                        }

                        Image(systemName: "chevron.down")
                            .font(.caption2)
                            .foregroundColor(.oaiSecondary)
                    }
                } else {
                    HStack(spacing: 4) {
                        Text("No model selected")
                            .font(.system(size: settings.guiTextSize))
                            .foregroundColor(.oaiSecondary)

                        Image(systemName: "chevron.down")
                            .font(.caption2)
                            .foregroundColor(.oaiSecondary)
                    }
                }
            }
            .buttonStyle(.plain)
            .help("Select model")

            Spacer()

            // Status indicators
            HStack(spacing: 8) {
                if model?.capabilities.imageGeneration == true {
                    StatusPill(icon: "paintbrush", label: "Image", color: .purple)
                }
                if onlineMode {
                    StatusPill(icon: "globe", label: "Online", color: .green)
                }
                if mcpEnabled {
                    StatusPill(icon: "folder", label: "MCP", color: .blue)
                }
                if settings.syncEnabled && settings.syncAutoSave {
                    SyncStatusPill()
                }
            }

            // Divider between status and stats
            if onlineMode || mcpEnabled || model?.capabilities.imageGeneration == true || (settings.syncEnabled && settings.syncAutoSave) {
                Divider()
                    .frame(height: 16)
                    .opacity(0.5)
            }

            // Quick stats
            HStack(spacing: 16) {
                StatItem(icon: "message", value: "\(stats.messageCount)")
                StatItem(icon: "arrow.up.arrow.down", value: stats.totalTokensDisplay)
                StatItem(icon: "dollarsign", value: stats.totalCostDisplay)
            }
            .font(.caption)
        }
        .padding(.horizontal, 16)
        .padding(.vertical, 10)
        .background(.ultraThinMaterial)
        .overlay(
            Rectangle()
                .fill(Color.oaiBorder.opacity(0.5))
                .frame(height: 1),
            alignment: .bottom
        )
    }
}

struct StatItem: View {
    let icon: String
    let value: String
    private let settings = SettingsService.shared

    var body: some View {
        HStack(spacing: 4) {
            Image(systemName: icon)
                .font(.system(size: settings.guiTextSize - 3))
                .foregroundColor(.oaiSecondary)
            Text(value)
                .font(.system(size: settings.guiTextSize - 1, weight: .medium))
                .foregroundColor(.oaiPrimary)
        }
    }
}

struct StatusPill: View {
    let icon: String
    let label: String
    let color: Color

    var body: some View {
        HStack(spacing: 3) {
            Circle()
                .fill(color)
                .frame(width: 6, height: 6)
            Text(label)
                .font(.system(size: 10, weight: .medium))
                .foregroundColor(.oaiSecondary)
        }
        .padding(.horizontal, 6)
        .padding(.vertical, 2)
        .background(color.opacity(0.1), in: Capsule())
    }
}

struct SyncStatusPill: View {
    private let gitSync = GitSyncService.shared
    @State private var syncColor: Color = .secondary
    @State private var syncLabel: String = "Sync"
    @State private var tooltipText: String = ""

    var body: some View {
        HStack(spacing: 3) {
            Circle()
                .fill(syncColor)
                .frame(width: 6, height: 6)
            Text(syncLabel)
                .font(.system(size: 10, weight: .medium))
                .foregroundColor(.oaiSecondary)
        }
        .padding(.horizontal, 6)
        .padding(.vertical, 2)
        .background(syncColor.opacity(0.1), in: Capsule())
        .help(tooltipText)
        .onAppear {
            updateState()
        }
        .onChange(of: gitSync.syncStatus) {
            updateState()
        }
        .onChange(of: gitSync.isSyncing) {
            updateState()
        }
        .onChange(of: gitSync.lastSyncError) {
            updateState()
        }
    }

    private func updateState() {
        // Determine sync state
        if let error = gitSync.lastSyncError {
            syncColor = .red
            syncLabel = "Error"
            tooltipText = "Sync failed: \(error)"
        } else if gitSync.isSyncing {
            syncColor = .orange
            syncLabel = "Syncing"
            tooltipText = "Syncing..."
        } else if gitSync.syncStatus.isCloned {
            syncColor = .green
            syncLabel = "Synced"
            if let lastSync = gitSync.syncStatus.lastSyncTime {
                tooltipText = "Last synced: \(timeAgo(lastSync))"
            } else {
                tooltipText = "Synced"
            }
        } else {
            syncColor = .secondary
            syncLabel = "Sync"
            tooltipText = "Sync not configured"
        }
    }

    private func timeAgo(_ date: Date) -> String {
        let seconds = Int(Date().timeIntervalSince(date))
        if seconds < 60 {
            return "just now"
        } else if seconds < 3600 {
            let minutes = seconds / 60
            return "\(minutes)m ago"
        } else if seconds < 86400 {
            let hours = seconds / 3600
            return "\(hours)h ago"
        } else {
            let days = seconds / 86400
            return "\(days)d ago"
        }
    }
}

#Preview {
    VStack {
        HeaderView(
            provider: .openrouter,
            model: ModelInfo.mockModels.first,
            stats: SessionStats(
                totalInputTokens: 125,
                totalOutputTokens: 434,
                totalCost: 0.00111,
                messageCount: 4
            ),
            onlineMode: true,
            mcpEnabled: true,
            mcpStatus: "MCP",
            onModelSelect: {},
            onProviderChange: { _ in }
        )
        Spacer()
    }
    .background(Color.oaiBackground)
}