//
//  ITunesSearchService.swift
//  QuickLocation
//

import Foundation

enum ITunesSearchError: Error {
    case invalidURL
    case invalidResponse
}

enum ITunesSearchService {
    private struct SearchResponse: Decodable {
        let results: [ITunesAppResult]
    }

    private struct ITunesAppResult: Decodable {
        let trackId: Int
        let trackName: String
        let artworkUrl100: String?
        let artworkUrl512: String?
    }

    static func search(term: String, limit: Int = 25) async throws -> [AppCatalogItem] {
        let trimmed = term.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !trimmed.isEmpty else { return [] }

        var components = URLComponents(string: "https://itunes.apple.com/search")
        components?.queryItems = [
            URLQueryItem(name: "term", value: trimmed),
            URLQueryItem(name: "entity", value: "software"),
            URLQueryItem(name: "country", value: "cn"),
            URLQueryItem(name: "limit", value: "\(limit)")
        ]
        guard let url = components?.url else { throw ITunesSearchError.invalidURL }

        let (data, response) = try await URLSession.shared.data(from: url)
        guard let http = response as? HTTPURLResponse, (200...299).contains(http.statusCode) else {
            throw ITunesSearchError.invalidResponse
        }

        let decoded = try JSONDecoder().decode(SearchResponse.self, from: data)
        return decoded.results.map { result in
            let iconURL = result.artworkUrl512 ?? result.artworkUrl100
            return AppCatalogItem(
                id: "itunes:\(result.trackId)",
                name: result.trackName,
                icon: "",
                keywords: [],
                iconURL: iconURL
            )
        }
    }

    static func mergedResults(local: [AppCatalogItem], remote: [AppCatalogItem]) -> [AppCatalogItem] {
        var seen = Set<String>()
        var merged: [AppCatalogItem] = []
        for item in local + remote {
            guard !seen.contains(item.id) else { continue }
            seen.insert(item.id)
            merged.append(item)
        }
        return merged
    }
}