//
//  BaseTableViewController.swift
//  MTP2_iOS
//
//  Created by zhongyuan on 2018/4/11.
//  Copyright © 2018年 zhongyuan.All rights reserved.
//

import UIKit

class BaseTableViewController<Model>: BaseViewController, UITableViewDataSource, UITableViewDelegate {
    
    /// 要显示的数据
    var tableCellModels = [Model]()
    /// cell重用标识
    var cellReuseIdentifier: String?
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return tableCellModels.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        assert(cellReuseIdentifier != nil, "请在子类中设置cellReuseIdentifier")
        /// 要求必须注册cell
        let cell = tableView.dequeueReusableCell(withIdentifier: cellReuseIdentifier!, for: indexPath) as! BaseTableViewCell<Model>
        cell.rowNum = indexPath.row
        cell.takeInfo = takeInfo
        cell.model = tableCellModels[indexPath.row]
        return cell
    }
    
    /// 注意，子类中需要用到的方法在这个类中都要定义，让子类覆盖的方式实现。否则，这个类没有实现的方法，子类不能覆盖，也不能继承！！！
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)
    }
    
    /// 定义已便让子类覆盖
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return UITableView.automaticDimension
    }
    
    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        return nil
    }
    
    func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 0
    }
    
    func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
        return 0
    }
    
    func tableView(_ tableView: UITableView, viewForFooterInSection section: Int) -> UIView? {
        return nil
    }
    
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {}
    
    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {}
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {}
    
    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {}
}


protocol GroupedTableViewDelegate {
    
    associatedtype Models
    
    var sections: Int { get }
    var rowsInSection: [Int] { get }
    subscript(row: Int, section: Int) -> Models { get set }
}

class GroupedTableViewController<Model>: BaseTableViewController<Model>, GroupedTableViewDelegate {
    
    lazy var rowsInSection = [Int](repeating: 0, count: sections-1)
    lazy var sections = 0
    typealias Models = Model
    
    func indexIsValid(row: Int, section: Int) -> Bool {

        return row >= 0 && row < rowsInSection[section] && section >= 0 && section < sections
    }
    
    func getRowAndSection(index: Int) -> (row: Int, section: Int)? {
        guard index < tableCellModels.count else { return nil }
        var indexs = 0
        for i in 0 ..< sections {
            if index < indexs + rowsInSection[i] {
                return (row: index - indexs, section: i)
            }
            indexs += rowsInSection[i]
        }
        return nil
    }
    
    func getModel(index: Int) -> Model? {
        guard index < tableCellModels.count - 1 else { return nil }
        var indexs = 0
        for i in 0 ..< sections - 1 {
            if index < indexs + rowsInSection[i] {
                return self[index - indexs, i]
            }
            indexs += rowsInSection[i]
        }
        return nil
    }
    
    subscript(row: Int, section: Int) -> Model {
        get {
            return getModel(row: row, section: section)
        }
        set {
            setModel(row: row, section: section, newModel: newValue)
        }
    }
    
    private final func getModel(row: Int, section: Int) -> Model {
        var rows = 0
        for i in 0..<section {
            rows += rowsInSection[i]
        }
        return tableCellModels[rows + row]
    }
    
   private final func setModel(row: Int, section: Int, newModel: Model) {
        var rows = 0
        for i in 0..<section {
            rows += rowsInSection[i]
        }
        tableCellModels[rows + row] = newModel
    }
    
    override func numberOfSections(in tableView: UITableView) -> Int {
        return sections
    }
    
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return rowsInSection[section]
    }
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        assert(cellReuseIdentifier != nil, "请在子类中设置cellReuseIdentifier")
        /// 要求必须注册cell
        let cell = tableView.dequeueReusableCell(withIdentifier: cellReuseIdentifier!, for: indexPath) as! BaseTableViewCell<Model>
        cell.rowNum = indexPath.row
        cell.takeInfo = takeInfo
        cell.model = getModel(row: indexPath.row, section: indexPath.section)
        return cell
    }
}