//
//  Hashtag.swift
//  Pachyderm
//
//  Created by Shadowfacts on 9/9/18.
//  Copyright © 2018 Shadowfacts. All rights reserved.
//

import Foundation
import WebURL
import WebURLFoundationExtras

public class Hashtag: Codable {
    public let name: String
    public let url: URL
    /// Only present when returned from the trending hashtags endpoint
    public let history: [History]?
    
    public init(name: String, url: URL) {
        self.name = name
        self.url = url
        self.history = nil
    }
    
    public required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        self.name = try container.decode(String.self, forKey: .name)
        // pixelfed (possibly others) don't fully escape special characters in the hashtag url
        do {
            let webURL = try container.decode(WebURL.self, forKey: .url)
            if let url = URL(webURL) {
                self.url = url
            } else {
                let s = try? container.decode(String.self, forKey: .url)
                throw DecodingError.dataCorruptedError(forKey: .url, in: container, debugDescription: "unable to convert WebURL \(s?.debugDescription ?? "nil") to URL")
            }
        } catch {
            self.url = try container.decode(URL.self, forKey: .url)
        }
        self.history = try container.decodeIfPresent([History].self, forKey: .history)
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(name, forKey: .name)
        try container.encode(url.absoluteString, forKey: .url)
        try container.encodeIfPresent(history, forKey: .history)
    }
    
    private enum CodingKeys: String, CodingKey {
        case name
        case url
        case history
    }
}

extension Hashtag: Equatable, Hashable {
    public static func ==(lhs: Hashtag, rhs: Hashtag) -> Bool {
        return lhs.name == rhs.name
    }
    
    public func hash(into hasher: inout Hasher) {
        hasher.combine(url)
    }
}