//
//  Node.swift
//  MongoView
//
//  Created by Shadowfacts on 1/9/20.
//  Copyright © 2020 Shadowfacts. All rights reserved.
//

import Foundation
import MongoSwift

class Node {
    let key: Key?
    let value: BSON
    
    lazy private(set) var children: [Node] = {
        switch value {
        case let .array(array):
            return array.enumerated().map { (index, val) in
                Node(key: .index(index), value: val)
            }
        case let .document(doc):
            return doc.map { (key, val) in
                Node(key: .name(key), value: val)
            }
        default:
            return []
        }
    }()
    
    var numberOfChildren: Int {
        children.count
    }
    
    var hasChildren: Bool {
        numberOfChildren > 0
    }

    init(key: Key? = nil, value: BSON) {
        self.key = key
        self.value = value
    }
    
    convenience init(document: Document) {
        if case let .objectId(id) = document["_id"] {
            self.init(key: .objectId(id), value: .document(document))
        } else {
            self.init(key: nil, value: .document(document))
        }
    }
}

extension Node {
    enum Key {
        case index(Int)
        case name(String)
        case objectId(ObjectId)
    }
}

extension Node {
    static let dateFormatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.locale = .current
        formatter.setLocalizedDateFormatFromTemplate("yyyy-MM-dd HH:mm:ss ZZ")
        return formatter
    }()
    
    var keyString: String {
        switch key {
        case nil:
            return ""
        case let .index(index):
            return index.description
        case let .name(name):
            return name
        case let .objectId(id):
            return id.description
        }
    }
    
    var valueString: String {
        switch value {
        case let .double(value):
            return value.description
        case let .string(value):
            return value
        case let .document(doc):
            return "(\(doc.count) field\(doc.count == 1 ? "" : "s"))"
        case let .array(array):
            return "(\(array.count) element\(array.count == 1 ? "" : "s"))"
        case let .binary(value):
            switch Binary.Subtype(rawValue: value.subtype) {
            case nil:
                return "(unknown binary data)"
            case .generic:
                return "(generic binary data)"
            case .function:
                return "(function binary data)"
            case .binaryDeprecated:
                return "(binary data)"
            case .uuidDeprecated:
                fallthrough
            case .uuid:
                return try! UUID(from: value).description
            case .md5:
                return "(MD5 binary data)"
            case .userDefined:
                return "(user defined binary data)"
            }
        case .undefined:
            return "undefined"
        case let .objectId(value):
            return value.description
        case let .bool(value):
            return value.description
        case let .datetime(value):
            return value.description
        case .null:
            return "null"
        case let .regex(value):
            return try! NSRegularExpression(from: value).description
        case let .dbPointer(value):
            return "\(value.ref)(\(value.id))"
        case let .symbol(value):
            return value.description
        case let .code(value):
            return value.code
        case let .codeWithScope(value):
            return value.code
        case let .int32(value):
            return value.description
        case let .timestamp(value):
            let date = Date(timeIntervalSince1970: TimeInterval(value.timestamp))
            return Node.dateFormatter.string(from: date)
        case let .int64(value):
            return value.description
        case let .decimal128(value):
            return value.description
        case .minKey:
            return "(min key)"
        case .maxKey:
            return "(max key)"
        }
    }
}