//
//  ConversationListView.swift
//  oAI
//
//  Saved conversations list
//

import os
import SwiftUI

struct ConversationListView: View {
    @Environment(\.dismiss) var dismiss
    @State private var searchText = ""
    @State private var conversations: [Conversation] = []
    var onLoad: ((Conversation) -> Void)?

    private var filteredConversations: [Conversation] {
        if searchText.isEmpty {
            return conversations
        }
        return conversations.filter {
            $0.name.lowercased().contains(searchText.lowercased())
        }
    }

    var body: some View {
        VStack(spacing: 0) {
            // Header
            HStack {
                Text("Conversations")
                    .font(.system(size: 18, weight: .bold))
                Spacer()
                Button { dismiss() } label: {
                    Image(systemName: "xmark.circle.fill")
                        .font(.title2)
                        .foregroundStyle(.secondary)
                }
                .buttonStyle(.plain)
                .keyboardShortcut(.escape, modifiers: [])
            }
            .padding(.horizontal, 24)
            .padding(.top, 20)
            .padding(.bottom, 12)

            // Search bar
            HStack(spacing: 8) {
                Image(systemName: "magnifyingglass")
                    .foregroundStyle(.secondary)
                TextField("Search conversations...", text: $searchText)
                    .textFieldStyle(.plain)
                if !searchText.isEmpty {
                    Button { searchText = "" } label: {
                        Image(systemName: "xmark.circle.fill")
                            .foregroundStyle(.tertiary)
                    }
                    .buttonStyle(.plain)
                }
            }
            .padding(10)
            .background(.quaternary.opacity(0.5), in: RoundedRectangle(cornerRadius: 8))
            .padding(.horizontal, 24)
            .padding(.bottom, 12)

            Divider()

            // Content
            if filteredConversations.isEmpty {
                Spacer()
                VStack(spacing: 8) {
                    Image(systemName: searchText.isEmpty ? "tray" : "magnifyingglass")
                        .font(.largeTitle)
                        .foregroundStyle(.tertiary)
                    Text(searchText.isEmpty ? "No Saved Conversations" : "No Matches")
                        .font(.headline)
                        .foregroundStyle(.secondary)
                    Text(searchText.isEmpty ? "Conversations you save will appear here" : "Try a different search term")
                        .font(.caption)
                        .foregroundStyle(.tertiary)
                }
                Spacer()
            } else {
                List {
                    ForEach(filteredConversations) { conversation in
                        ConversationRow(conversation: conversation)
                            .contentShape(Rectangle())
                            .onTapGesture {
                                onLoad?(conversation)
                                dismiss()
                            }
                            .swipeActions(edge: .trailing, allowsFullSwipe: false) {
                                Button(role: .destructive) {
                                    deleteConversation(conversation)
                                } label: {
                                    Label("Delete", systemImage: "trash")
                                }

                                Button {
                                    exportConversation(conversation)
                                } label: {
                                    Label("Export", systemImage: "square.and.arrow.up")
                                }
                                .tint(.blue)
                            }
                    }
                }
                .listStyle(.plain)
            }

            Divider()

            // Bottom bar
            HStack {
                Spacer()
                Button("Done") { dismiss() }
                    .keyboardShortcut(.return, modifiers: [])
                    .buttonStyle(.borderedProminent)
                    .controlSize(.regular)
                Spacer()
            }
            .padding(.horizontal, 24)
            .padding(.vertical, 12)
        }
        .onAppear {
            loadConversations()
        }
        .frame(minWidth: 500, minHeight: 400)
    }

    private func loadConversations() {
        do {
            conversations = try DatabaseService.shared.listConversations()
        } catch {
            Log.db.error("Failed to load conversations: \(error.localizedDescription)")
            conversations = []
        }
    }

    private func deleteConversation(_ conversation: Conversation) {
        do {
            let _ = try DatabaseService.shared.deleteConversation(id: conversation.id)
            withAnimation {
                conversations.removeAll { $0.id == conversation.id }
            }
        } catch {
            Log.db.error("Failed to delete conversation: \(error.localizedDescription)")
        }
    }

    private func exportConversation(_ conversation: Conversation) {
        guard let (_, loadedMessages) = try? DatabaseService.shared.loadConversation(id: conversation.id),
              !loadedMessages.isEmpty else {
            return
        }
        let content = loadedMessages.map { msg in
            let header = msg.role == .user ? "**User**" : "**Assistant**"
            return "\(header)\n\n\(msg.content)"
        }.joined(separator: "\n\n---\n\n")

        let downloads = FileManager.default.urls(for: .downloadsDirectory, in: .userDomainMask).first
            ?? FileManager.default.temporaryDirectory
        let filename = conversation.name.replacingOccurrences(of: " ", with: "_") + ".md"
        let fileURL = downloads.appendingPathComponent(filename)
        try? content.write(to: fileURL, atomically: true, encoding: .utf8)
    }
}

struct ConversationRow: View {
    let conversation: Conversation

    var body: some View {
        VStack(alignment: .leading, spacing: 6) {
            Text(conversation.name)
                .font(.headline)

            HStack(spacing: 8) {
                Label("\(conversation.messageCount)", systemImage: "message")
                Text("\u{2022}")
                Text(conversation.updatedAt, style: .relative)
            }
            .font(.caption)
            .foregroundColor(.secondary)
        }
        .padding(.vertical, 4)
    }
}

#Preview {
    ConversationListView()
}