//
//  DownloadWindowController.m
//  Ample
//
//  Created by Kelvin Sherlock on 9/2/2020.
//  Copyright © 2020 Kelvin Sherlock. All rights reserved.
//

#import "Ample.h"
#import "DownloadWindowController.h"

enum {
    ItemMissing = 0,
    ItemFound,
    ItemDownloading,
    ItemDownloaded,
    ItemCanceled,
    ItemError
};

@interface DownloadItem : NSObject

@property NSString *name;
@property NSError *error;
@property NSString *pathName;
@property NSURLSessionDownloadTask *task;
@property NSURL *localURL;

@property NSUInteger status;
@property NSUInteger index;


-(void)cancelDownload;
-(void)beginDownloadWithTask:(NSURLSessionDownloadTask *)task;
-(void)completeWithError: (NSError *)error;
-(NSString *)statusDescription;
@end



@interface DownloadWindowController ()
@property (weak) IBOutlet NSTableView *tableView;

@end

@implementation DownloadWindowController {
    
    NSArray *_items;
    NSURL *_romFolder;
    NSURL *_sourceURL;
    NSURLSession *_session;
    NSMutableDictionary *_taskIndex;
}

+(instancetype)sharedInstance {
    static DownloadWindowController *me = nil;
    if (!me) {
        me = [self new];
    }
    return me;
}

+ (void)restoreWindowWithIdentifier:(nonnull NSUserInterfaceItemIdentifier)identifier state:(nonnull NSCoder *)state completionHandler:(nonnull void (^)(NSWindow * _Nullable, NSError * _Nullable))completionHandler {
    NSLog(@"restore rom manager window");

    NSWindowController *controller = [DownloadWindowController sharedInstance];
    NSWindow *w = [controller window];
    [w restoreStateWithCoder: state];
    completionHandler(w, nil);
}

#if 0
- (void)encodeWithCoder:(nonnull NSCoder *)coder {
    
}
#endif

-(NSString *)windowNibName {
    return @"DownloadWindow";
}

- (void)windowDidLoad {
    [super windowDidLoad];
    NSWindow *window = [self window];
    [window setRestorable: YES];
    [window setRestorationClass: [self class]];
    
    // Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.

    NSError *error = nil;
    NSBundle *bundle = [NSBundle mainBundle];
    NSFileManager *fm = [NSFileManager defaultManager];

    NSURL *url = [bundle URLForResource: @"roms" withExtension: @"plist"];
    
    NSDictionary *d = [NSDictionary dictionaryWithContentsOfURL: url];
    
    NSURL *sd = SupportDirectory();
    NSString *romdir = [SupportDirectoryPath() stringByAppendingPathComponent: @"roms"];

    _romFolder = [sd URLByAppendingPathComponent: @"roms"];
    
    [fm createDirectoryAtURL: _romFolder withIntermediateDirectories: YES attributes: nil error: &error];


    NSArray *roms = [d objectForKey: @"roms"];
    [self setCurrentROM: @""];
    [self setCurrentCount: 0];
    [self setTotalCount: [roms count]];
    [self setErrorCount: 0];
    _sourceURL = [NSURL URLWithString: @"https://archive.org/download/mame0224_rom"]; // hardcoded....
    
    
    NSMutableArray *tmp = [NSMutableArray arrayWithCapacity: [roms count]];
    unsigned ix = 0;
    for (NSString *name in roms) {
        
        DownloadItem *item  = [DownloadItem new];
        [item setName: name];
        [item setIndex: ix++];

        [tmp addObject: item];

        // check if the file exists.
        NSString *s = [romdir stringByAppendingPathComponent: name];
        NSString *path;

        path = [s stringByAppendingPathExtension: @"zip"];
        if ([fm fileExistsAtPath: path]) {
            [item setStatus: ItemFound];
            [item setLocalURL: [NSURL fileURLWithPath: path]];
            continue;
        }
        path = [s stringByAppendingPathExtension: @"7z"];
        if ([fm fileExistsAtPath: path]) {
            [item setStatus: ItemFound];
            [item setLocalURL: [NSURL fileURLWithPath: path]];
            continue;
        }
    }
    _items = tmp;
 
    NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
    _session = [NSURLSession sessionWithConfiguration: config delegate: self delegateQueue: nil];
    _taskIndex = [NSMutableDictionary dictionaryWithCapacity: [_items count]];
    
    //[self download];
}

-(void)downloadItem: (DownloadItem *)item {

    if (!_session) {
        NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
        _session = [NSURLSession sessionWithConfiguration: config delegate: self delegateQueue: nil];
    }
    
    NSURLSessionDownloadTask *task;
    NSString *s = [item name];
    NSString *path = [s stringByAppendingString: @".7z"]; // hardcoded.
    NSURL *url = [_sourceURL URLByAppendingPathComponent: path];
    
    task = [_session downloadTaskWithURL: url];
    
    [item beginDownloadWithTask: task];
    [_taskIndex setObject: item forKey: task];

    [task resume];
    
}

-(void)download {
    


    // run in thread?
    //unsigned count = 0;
    for (DownloadItem *item in _items) {
            
        NSURLSessionDownloadTask *task;
        NSString *s = [item name];
        NSString *path = [s stringByAppendingString: @".7z"]; // hardcoded.
        NSURL *url = [_sourceURL URLByAppendingPathComponent: path];
        
        task = [_session downloadTaskWithURL: url];
        [_taskIndex setObject: item forKey: task];
        
        [item setTask: task];

        [task resume];

        //++count;
        //if (count >= 2) break;
    }
    [self setActive: YES];
    
}

-(DownloadItem *)clickedItem {
    NSInteger row = [_tableView clickedRow];
    if (row < 0 || row >= [_items count]) return nil;
    return [_items objectAtIndex: row];
}
-(void)redrawRow: (NSUInteger)row {
    
    //NSRect r = [_tableView rectOfRow: row];
    //[_tableView setNeedsDisplayInRect: r];
    
    NSIndexSet *rIx = [NSIndexSet indexSetWithIndex: row];
    NSIndexSet *cIx = [NSIndexSet indexSetWithIndex: 0];
    
    [_tableView reloadDataForRowIndexes: rIx columnIndexes: cIx];
}
#pragma mark - IBActions

-(IBAction)cancelAll:(id)sender {

    for (DownloadItem *item in _items) {
        [item cancelDownload];
    }

    [_session invalidateAndCancel];
    _session = nil;
    [_taskIndex removeAllObjects];
    [self setCurrentCount: 0];
    [self setActive: NO];

    [_tableView reloadData];
    //[_tableView setNeedsDisplay: YES]; // doesn't work...
}

- (IBAction)downloadMissing:(id)sender {

    BOOL delta = NO;
    for (DownloadItem *item in _items) {
        NSURL *url = [item localURL];
        id task = [item task];
        if (!url && !task) {
            [self downloadItem: item];
            delta = YES;
        }
    }
    
    if (delta) {
        [self setActive: YES];
        [_tableView reloadData];
    }
}

- (IBAction)showInFinder:(id)sender {
    DownloadItem *item = [self clickedItem];
    if (!item) return;
    NSURL *url = [item localURL];
    if (!url) return;

    NSWorkspace *ws = [NSWorkspace sharedWorkspace];
    [ws activateFileViewerSelectingURLs: @[url]];
}

- (IBAction)download:(id)sender {
    DownloadItem *item = [self clickedItem];
    if (!item) return;

    [self downloadItem: item];
    [self setActive: YES];
    [self redrawRow: [item index]];
}
- (IBAction)cancel:(id)sender {
    DownloadItem *item = [self clickedItem];
    if (!item) return;

    [item cancelDownload];
    [self redrawRow: [item index]];
}


#pragma mark - NSURLSessionDelegate

-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {


    // not sure if strictly necessary but this happens in a background thread
    // and these are used in KVO binding.  Also, main thread only
    // means no race conditions.
    dispatch_async(dispatch_get_main_queue(), ^(void){
        if (error)
            [self setErrorCount: self->_errorCount + 1];
        else
            [self setCurrentCount: self->_currentCount + 1];
        
        NSMutableDictionary *taskIndex = self->_taskIndex;
        DownloadItem *item = [taskIndex objectForKey: task];
        [taskIndex removeObjectForKey: task];

        if ([taskIndex count] == 0) {
            [self setActive: NO];
        }
        
        if (item) {
            [item completeWithError: error];
            NSUInteger row = [item index];
            
            [self redrawRow: row];
        }
    });
    
}

- (void)URLSession:(NSURLSession *)session downloadTask:(nonnull NSURLSessionDownloadTask *)task didFinishDownloadingToURL:(nonnull NSURL *)location {


    // need to move to the destination directory...
    // file deleted after this function returns, so can't move asynchronously.
    NSFileManager *fm = [NSFileManager defaultManager];
    NSURL *src = [[task originalRequest] URL];
    NSURL *dest = [_romFolder URLByAppendingPathComponent: [src lastPathComponent]];
    NSError *error = nil;
    
    [fm moveItemAtURL: location toURL: dest error: &error];

    DownloadItem *item = [_taskIndex objectForKey: task];
    [item setLocalURL: dest];

    /*
    dispatch_async(dispatch_get_main_queue(), ^(void){


        [item setLocalURL: dest];
    }
    */
    NSLog(@"%@", src);
}

@end

@implementation DownloadWindowController (Table)

- (NSInteger)numberOfRowsInTableView:(NSTableView *)tableView {
    return [_items count];
}

- (id)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
    
    return [_items objectAtIndex: row];
}


- (NSView *)tableView:(NSTableView *)tableView viewForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
 
    DownloadItem *item = [_items objectAtIndex: row];
    DownloadTableCellView *v = [tableView makeViewWithIdentifier: @"DownloadCell" owner: self];
    
    NSTextField *tf;
    
    tf = [v textField];
    [[v textField] setObjectValue: [item name]];
    
    if ([item localURL]) {
        [tf setTextColor: [NSColor blackColor]];
    } else {
        [tf setTextColor: [NSColor redColor]];
    }
    
    tf = [v statusTextField];
    [tf setObjectValue: [item statusDescription]];
    if ([item error]) {
        [tf setTextColor: [NSColor redColor]];
    } else {
        [tf setTextColor: [NSColor blackColor]];
        //if ([tableView isRowSelected: row]){
            //[tf setTextColor: [NSColor whiteColor]];
        //}
    }

    if ([item task]) {
        [[v activity] startAnimation: nil];
    } else {
        [[v activity] stopAnimation: nil];
    }
    
    
    return v;
}


@end


@implementation DownloadTableCellView

@end

@implementation DownloadItem

-(void)beginDownloadWithTask:(NSURLSessionDownloadTask *)task {
    _task = task;
    _error = nil;
    if (task) _status = ItemDownloading;
}

-(void)cancelDownload {
    if (!_task) return;
    [_task cancel];
    _task = nil;
    _status = ItemCanceled;
}

-(void)completeWithError: (NSError *)error {
    _task = nil;
    if (error) {
        _error = error;
        _status = ItemError;
    } else {
        // what if there was an error moving it?
        _error = nil;
        _status = ItemDownloaded;
    }
}

-(NSString *)statusDescription {

    static NSString *Names[] = {
        @"ROM missing",
        @"ROM found",
        @"Downloading…",
        @"Downloaded",
        @"Canceled",
        @"Error"
    };
    if (_error) return [_error description];

    if (_status > sizeof(Names)/sizeof(Names[0])) return @"Unknown";
    return Names[_status];
}

@end



@implementation DownloadWindowController (Menu)

enum {
    kOpenInFinder = 1,
    kDownload,
    kCancel,
};

- (BOOL)validateMenuItem:(NSMenuItem *)menuItem {
    NSInteger row = [_tableView clickedRow];
    if (row < 0) return NO;
    DownloadItem *item = [_items objectAtIndex: row];
    
    NSUInteger status = [item status];
    switch([menuItem tag]) {
        case kOpenInFinder:
            return status == ItemFound || status == ItemDownloaded;
            break;
        case kDownload:
            return YES;
            //return status == ItemMissing || status == ItemError || status == ItemCanceled;
            break;
        case kCancel:
            return status == ItemDownloading;
            break;
            
    }
    return NO;
}

@end