Add team score over time line graphs

[glen3b]

Add line graphs of team scores over time.

[glen3b]

Unfortunately I can't seem find a good .NET Core bitmap manipulation library, which makes this harder.

[glen3b]

Something like OxyPlot can render a graph to an SVG, but Discord does not accept SVG image embeds, so a PNG renderer is still required. It's possible we could build a platform abstraction library and make native calls for the rendering, which is ugly. There are bitmap libraries, such as ImageSharp, but I haven't looked at these in conjunction with SVG rendering. There are libraries such as vvvv/SVG, but that one in particular includes a reference to System.Drawing and is thus probably unsuitable without modification.

[glen3b]

Possibility is using my bitmap graphing library, which is written with this use case in mind, but it's another component to maintain.

[lighthouse64]

By graph, do you mean a histogram?

[glen3b]

The CCS scoreboard includes line graphs of individual team scores over time:

I'd like to replicate that in the bot.

[aopell]

Histograms of score distributions would not be a bad feature either

[glen3b]

I agree, feel free to open a separate feature issue for that.

[glen3b]

Proposed model for bitmaps (also relevant in #35):

Project CyberPatriot.BitmapProvider: common glue types and abstractions

• CyberPatriot.BitmapProvider.IGraphProviderService
  • Task WriteHistogramPngAsync(... some data arguments, maybe some rendering options like Color ..., Stream target)
• CyberPatriot.BitmapProvider.Color: an RGBA32 struct for color
• any other common types across bitmap libraries
• probably won't implement a complete, abstract, image drawing API here, just any common types which each individual backend can convert

Project CyberPatriot.BitmapProvider.ImageSharp: Implementation backed by ImageSharp

• ImageSharpGraphProviderService : CyberPatriot.BitmapProvider.IGraphProviderService, uses an Image and drawing tools to generate the requisite bitmaps, can probably also reference BitmapGraphing (which is pretty tightly tied to ImageSharp) for line graphing

In terms of the line graphing, BitmapGraphing needs work, but I think it's a good start

[glen3b]

In terms of data retrieval:
We'll add another method to the score retriever interface. Possible return types:

• A Dictionary<string, Something>, keyed by image name and with values being an enumerable of DTO to int keyvaluepairs (or a custom struct)
• A Dictionary<string, SortedDictionary<DateTimeOffset, int>>
• A custom type overriding indexers of [string] and of [string, DateTimeOffset], mirroring a Dictionary<string, SortedDictionary<DateTimeOffset, int>> in terms of behavior. Largely matches the actual implementation's initialization code:

    var data = new google.visualization.arrayToDataTable([
['Time', 'Debian7_regional_platinum', 'Ubuntu14_regional_platinum', 'Windows8_regional_platinum'],
['02/05 17:15', 9, 4, 3],
['02/05 17:20', 16, 22, 9],
['02/05 17:25', 27, 22, 22],
['02/05 17:30', 34, 24, 37],
['02/05 17:35', 45, 36, 41],
['02/05 17:40', 45, 43, 50],
['02/05 17:45', 50, 55, 59],
['02/05 17:50', 56, 58, 69],
['02/05 17:55', 64, 77, 69],
['02/05 18:00', 64, 77, 73],
['02/05 18:05', 64, 77, 73],
['02/05 18:10', 67, 80, 73],
['02/05 18:15', 64, 80, 73],
['02/05 18:20', 64, 83, 75],
['02/05 18:25', 64, 83, 75],
...
['02/05 22:25', 57, 86, 85],
['02/05 22:30', 68, 86, 85],
['02/05 22:35', 73, 86, 85],
['02/05 22:40', 82, 86, 85],
['02/05 22:45', null, 86, null],
    ]);