//
//  CreditsView.swift
//  oAI
//
//  Account credits and balance
//
// 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 CreditsView: View {
    let provider: Settings.Provider
    @Environment(\.dismiss) var dismiss
    @State private var credits: Credits?
    @State private var isLoading = false
    @State private var errorMessage: String?

    var body: some View {
        NavigationStack {
            VStack(spacing: 24) {
                // Provider icon
                Image(systemName: provider.iconName)
                    .font(.system(size: 60))
                    .foregroundColor(Color.providerColor(provider))

                Text(provider.displayName)
                    .font(.title2)
                    .fontWeight(.semibold)

                Divider()

                // Credits info based on provider
                VStack(spacing: 16) {
                    switch provider {
                    case .openrouter:
                        openRouterCreditsView

                    case .anthropic:
                        Text("Anthropic Balance")
                            .font(.headline)
                        Text("Check your balance at:")
                            .font(.caption)
                            .foregroundColor(.secondary)
                        Link("console.anthropic.com", destination: URL(string: "https://console.anthropic.com")!)
                            .font(.body)

                    case .openai:
                        Text("OpenAI Balance")
                            .font(.headline)
                        Text("Check your usage at:")
                            .font(.caption)
                            .foregroundColor(.secondary)
                        Link("platform.openai.com", destination: URL(string: "https://platform.openai.com/usage")!)
                            .font(.body)

                    case .ollama:
                        Text("Ollama (Local)")
                            .font(.headline)
                        Text("Running locally — no credits needed!")
                            .font(.body)
                            .foregroundColor(.secondary)
                        Image(systemName: "checkmark.circle.fill")
                            .font(.system(size: 40))
                            .foregroundColor(.green)
                            .padding(.top)
                    }
                }

                Spacer()
            }
            .padding()
            .navigationTitle("Credits")
            .toolbar {
                ToolbarItem(placement: .confirmationAction) {
                    Button("Done") { dismiss() }
                }
            }
        }
        .task {
            await fetchCredits()
        }
    }

    // MARK: - OpenRouter Credits

    @ViewBuilder
    private var openRouterCreditsView: some View {
        Text("OpenRouter Credits")
            .font(.headline)

        if isLoading {
            ProgressView("Loading...")
                .padding()
        } else if let error = errorMessage {
            Text(error)
                .font(.caption)
                .foregroundColor(.red)
                .padding()
            Button("Retry") {
                Task { await fetchCredits() }
            }
        } else if let credits = credits {
            VStack(spacing: 12) {
                CreditRow(label: "Remaining", value: credits.balanceDisplay, highlight: true)
                Divider()
                if let limit = credits.limit {
                    CreditRow(label: "Total Credits", value: String(format: "$%.2f", limit))
                }
                if let usage = credits.usage {
                    CreditRow(label: "Used", value: String(format: "$%.2f", usage))
                }
            }
        } else {
            Text("No credit data available")
                .font(.caption)
                .foregroundColor(.secondary)
        }
    }

    private func fetchCredits() async {
        guard provider == .openrouter else { return }
        guard let apiProvider = ProviderRegistry.shared.getCurrentProvider() else {
            errorMessage = "No API key configured"
            return
        }

        isLoading = true
        errorMessage = nil

        do {
            credits = try await apiProvider.getCredits()
            isLoading = false
        } catch {
            errorMessage = error.localizedDescription
            isLoading = false
        }
    }
}

struct CreditRow: View {
    let label: String
    let value: String
    var highlight: Bool = false

    var body: some View {
        HStack {
            Text(label)
                .foregroundColor(highlight ? .primary : .secondary)
                .fontWeight(highlight ? .semibold : .regular)
            Spacer()
            Text(value)
                .font(highlight ? .title2.monospacedDigit() : .body.monospacedDigit())
                .fontWeight(highlight ? .bold : .medium)
                .foregroundColor(highlight ? .green : .primary)
        }
    }
}

#Preview {
    CreditsView(provider: .openrouter)
}