//
//  SearchProvider.swift
//  App
//
//  Created by James Magahern on 3/9/21.
//

import Foundation

class SearchProvider
{
    // Build a provider from a URL template. Template should contain %q or %s
    // which will be replaced with the sanitized query string.
    static func fromTemplate(_ template: String) -> SearchProvider {
        SearchProvider(resolver: { query in
            let sanitized = query.sanitized()
            let replaced = template
                .replacingOccurrences(of: "%q", with: sanitized)
                .replacingOccurrences(of: "%s", with: sanitized)
            return URL(string: replaced) ?? URL(string: "https://google.com/search?q=\(sanitized)&gbv=1")!
        })
    }

    static let google = SearchProvider(resolver: { query in
        // gbv=1: no JS
        URL(string: "https://google.com/search?q=\(query.sanitized())&gbv=1")!
    })
    
    static let duckduckgo = SearchProvider(resolver: { query in
        // html version is the one without JS
        URL(string: "https://html.duckduckgo.com/html/?q=\(query.sanitized())")!
    })
    
    static let searxnor = SearchProvider(resolver: { query in
        URL(string: "http://searx.nor/search?q=\(query.sanitized())&categories=general")!
    })
    
    static let whoogle = SearchProvider(resolver: { query in
        URL(string: "http://whoogle.nor/search?q=\(query.sanitized())")!
    })
    
    func searchURLWithQuery(_ query: String) -> URL {
        return resolver(query)
    }
    
    internal let resolver: (String) -> URL
    internal init(resolver: @escaping (String) -> URL) {
        self.resolver = resolver
    }
}

fileprivate extension String {
    func sanitized() -> String {
        self
            .replacingOccurrences(of: " ", with: "+")
            .addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
    }
}