//
//  iTunesSaveOperation.swift
//  TagTunes
//
//  Created by Kim Wittenburg on 08.04.16.
//  Copyright © 2016 Kim Wittenburg. All rights reserved.
//

import AppKitPlus

// TODO: Documentation

class SaveOperation<TrackType: TagTunesTrack>: Operation, NSProgressReporting {

    // TODO: Support Cancellation
    let progress = NSProgress(parent: nil, userInfo: nil)

    let track: TrackType
    let entity: TagTunesEntityItem
    let parentEntity: TagTunesGroupItem?

    init(track: TrackType, entity: TagTunesEntityItem) {
        self.track = track
        self.entity = entity
        self.parentEntity = entity.parentItem
        super.init()

        progress.cancellable = false
        progress.localizedDescription = entity.entity.name
        progress.localizedAdditionalDescription = "Pending…" // TODO: Localize
        addCondition(MutuallyExclusive<TrackType>())
    }

    override func execute() {
        dispatch_sync(dispatch_get_main_queue()) {
            self.progress.totalUnitCount = Int64(Tag.allTags.count)
            self.progress.completedUnitCount = 0
        }
        if track.supportsBatchSaving {
            executeBatchSave()
        } else {
            executeNormalSave()
        }
    }

    private func executeBatchSave() {
        dispatch_sync(dispatch_get_main_queue()) {
            self.progress.localizedAdditionalDescription = "Saving…" // TODO: Localize
        }
        var tags = [Tag: AnyObject?]()
        for tag in Tag.allTags {
            do {
                switch Preferences.sharedPreferences.tagSavingBehaviors[tag]! {
                case .Save:
                    tags[tag] = try entity.valueForTag(tag)
                case .Clear:
                    tags[tag] = nil
                case .Ignore:
                    break
                }
            } catch {
                logError(error as NSError)
            }
        }
        progress.becomeCurrentWithPendingUnitCount(progress.totalUnitCount)
        do {
            try track.saveTags(tags)
            finish()
        } catch {
            finishWithError(error as NSError)
        }
        progress.resignCurrent()
    }

    private func executeNormalSave() {
        for tag in Tag.allTags {
            dispatch_sync(dispatch_get_main_queue()) {
                self.progress.localizedAdditionalDescription = String(format: "Saving %@…", tag.localizedName) // TODO: Localize
            }
            do {
                switch Preferences.sharedPreferences.tagSavingBehaviors[tag]! {
                case .Save:
                    try track.saveValue(entity.valueForTag(tag), forTag: tag)
                case .Clear:
                    try track.saveValue(nil, forTag: tag)
                case .Ignore:
                    break
                }
            } catch {
                logError(error as NSError)
            }
            dispatch_sync(dispatch_get_main_queue()) {
                self.progress.completedUnitCount += 1
            }
        }
        finish()
    }

}