//
//  ActivityViewController.swift
//  TagTunes
//
//  Created by Kim Wittenburg on 22.03.16.
//  Copyright © 2016 Kim Wittenburg. All rights reserved.
//

import SearchAPI
import AppKitPlus

// TODO: Order Fields, Documentation

let saveQueue = OperationQueue()

// TODO: Better Name
private var operationsContext = 0

class ActivityViewController: NSViewController, OperationQueueDelegate {

    private struct Groups {
        static let Lookup: AnyObject = "LookupGroup"
        static let Save: AnyObject = "SaveGroup"
    }

    private static let LookupItem: AnyObject = "LookupActivityItem"

    // MARK: Properties

    @IBOutlet weak var outlineView: NSOutlineView!

    private var saveOperations = [SaveOperation]() {
        didSet {
            noteOutlineContentDidChange()
        }
    }

    // MARK: Initialization

    override init?(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        registerObservers()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        registerObservers()
    }

    private func registerObservers() {
        saveQueue.addObserver(self, forKeyPath: "operations", options: [], context: &operationsContext)
        LookupQueue.globalQueue.delegate = self
    }

    // MARK: Obersers and Delegates

    private func noteOutlineContentDidChange() {
        // TODO: Optimize this to reload single rows
        self.outlineView?.reloadData()
        self.outlineView?.expandItem(nil, expandChildren: true)
    }

    override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
        if context == &operationsContext {
            let operations = saveQueue.operations.flatMap { $0 as? SaveOperation }
            dispatch_async(dispatch_get_main_queue()) {
                self.saveOperations = operations
            }
        }
    }

    func operationQueue(operationQueue: OperationQueue, willAddOperation operation: NSOperation) {
        if operationQueue === LookupQueue.globalQueue {
            noteOutlineContentDidChange()
        }
    }

    func operationQueue(operationQueue: OperationQueue, operationDidFinish operation: NSOperation, withErrors errors: [NSError]) {
        // TODO: Why is this not on main thread and willAdd... is?
        dispatch_sync(dispatch_get_main_queue()) {
            if operationQueue === LookupQueue.globalQueue {
                self.noteOutlineContentDidChange()
            }
        }
    }
}

extension ActivityViewController: NSOutlineViewDataSource, NSOutlineViewDelegate {

    func outlineView(outlineView: NSOutlineView, numberOfChildrenOfItem item: AnyObject?) -> Int {
        if item == nil {
            return 2
        }
        if item === Groups.Lookup {
            return 0 // TODO: Return sometimes 1
        }
        if item === Groups.Save {
            return saveOperations.count
        }
        return 0
    }

    func outlineView(outlineView: NSOutlineView, child index: Int, ofItem item: AnyObject?) -> AnyObject {
        if item == nil {
            return [Groups.Lookup, Groups.Save][index]
        }
        if item === Groups.Lookup {
            return ActivityViewController.LookupItem
        }
        if item === Groups.Save {
            return saveOperations[index]
        }
        return ""
    }

    func outlineView(outlineView: NSOutlineView, isItemExpandable item: AnyObject) -> Bool {
        return self.outlineView(outlineView, isGroupItem: item)
    }

    func outlineView(outlineView: NSOutlineView, isGroupItem item: AnyObject) -> Bool {
        return item === Groups.Lookup || item === Groups.Save
    }

    func outlineView(outlineView: NSOutlineView, shouldShowOutlineCellForItem item: AnyObject) -> Bool {
        return false
    }

    func outlineView(outlineView: NSOutlineView, heightOfRowByItem item: AnyObject) -> CGFloat {
        if self.outlineView(outlineView, isGroupItem: item) {
            return 24
        } else {
            return 42
        }
    }

    func outlineView(outlineView: NSOutlineView, viewForTableColumn tableColumn: NSTableColumn?, item: AnyObject) -> NSView? {
        if item === Groups.Lookup {
            let view = outlineView.makeViewWithIdentifier("GroupCell", owner: nil) as? NSTableCellView
            // TODO: Localize
            view?.textField?.stringValue = "iTunes Match"
            return view
        }
        if item === Groups.Save {
            let view = outlineView.makeViewWithIdentifier("GroupCell", owner: nil) as? NSTableCellView
            // TODO: Localize
            view?.textField?.stringValue = "Saving"
            return view
        }
        print(item)
        if item === ActivityViewController.LookupItem {
            var view = outlineView.makeViewWithIdentifier("LookupCell", owner: nil) as? AdvancedTableCellView
            if view == nil {
                view = AdvancedTableCellView()
                view?.style = .Subtitle
                let progressIndicator = NSProgressIndicator()
                progressIndicator.controlSize = .RegularControlSize
                view?.leftAccessoryView = progressIndicator
            }
            // TODO: Localize
            view?.textField?.stringValue = "Looking up n tracks"
            view?.secondaryTextField?.stringValue = "m tracks in queue"
            return view
        }
        if let saveOperation = item as? SaveOperation {
            var view = outlineView.makeViewWithIdentifier("SaveCell", owner: nil) as? SaveTableCellView
            if view == nil {
                view = SaveTableCellView()
            }
            view?.progress = saveOperation.progress
            view?.leftAccessoryView = nil
            return view
        }
        return nil
    }

}