Theme Support

[itspngu]

Summary

This PR adds some initial/basic support for user-configurable themes. I didn't want to turn too many things inside out, which is why
there's a "shim" function that translates the user's color choices into the currently-used format; the idea being that the default theme ships a combined light + dark mode, but once a user writes their own theme, the complexity of that is unnecessary, as they're writing it for their own terminal, which is either light or dark.

On top of that, it's possible to set a useShellTheme bool in the config file, which skips custom themes altogether and instead uses the user's shell theme. I'm not sure if it looks good for everyone, perhaps that needs some testing/adjustment and maybe also the same light+dark logic of the default theme.

In summary, the config file generated on the first run now includes this (these are the colors for a dark terminal, for a light one it'd dump a different set of colors - I "transcribed" the default color scheme):

theme:
  colors:
    text:
      main: '#E2E1ED'
      secondary: '#666CA6'
      bright: '#E2E1ED'
      subtle: '#242347'
      faint: '#3E4057'
      warning: '#F23D5C'
      success: '#3DF294'
    background:
      selected: '#39386B'
    border:
      main: '#383B5B'
      secondary: '#39386B'
      faint: '#2B2B40'

I've deliberately put everything under a theme.colors sub-key, because looking at the open issues, there's a few things that'd probably fit well into a theme.layout (#107) or theme.options (#111) tree.

How did you test this change?

Barely, and I'm new to Go. Opening this as a draft to facilitate discussion about the implementation. When/if everything is agreed on code wise, I'd update the docs in a separate commit. Also looking at base16 to generate a set of themes, license wise gh-dash is compatible with it, but again, don't want to do too much at once.

Images/Videos

<making the robots happy>
Fixes #102
</making the robots happy>

If there's anything unclear, ask away, I have trouble articulating myself sometimes! :)

[dlvhdr]

Hey! Amazing stuff, thanks so much for contributing this! I'll go over it in the next couple of days 💖

[dlvhdr]

I made a whole mess with the colors :D
I think some are unused, and some are just badly named.
I left comments I think should make things more clear.

theme:
  colors:
    text:
      main: '#E2E1ED' # should probably be renamed to "primary"
      secondary: '#666CA6'
      bright: '#E2E1ED' # I actually searched the code and I don't think this is used
      subtle: '#242347' # This one is badly named. It's used for the pills which have a light background color and so need a dark text. Maybe it should be named "inverted"?
      faint: '#3E4057'
      warning: '#F23D5C'
      success: '#3DF294'
    background:
      selected: '#39386B'
    border:
      main: '#383B5B' # "primary"
      secondary: '#39386B'
      faint: '#2B2B40'

[dlvhdr]

Thanks for making the changes!

I forgot about the whole markdown renderer colors. Is that something you'd want to tackle in this PR maybe?
It could be a bit much for this one. If you don't have time etc, I can take it in a later PR.
I just noticed it doesn't look very good on light themes.

https://github.com/dlvhdr/gh-dash/blob/d25d8101d5717a4e10ae83c2d33ae8d1fb7a3a08/ui/markdown/theme.go

[dlvhdr]

I played around with the colors on a dark theme and light theme terminals and I think I like these colors better:

			SelectedBackground: lipgloss.AdaptiveColor{Light: "006", Dark: "008"},
			Border:             lipgloss.AdaptiveColor{Light: "013", Dark: "008"},
			FaintBorder:        lipgloss.AdaptiveColor{Light: "254", Dark: "000"},
			SecondaryBorder:    lipgloss.AdaptiveColor{Light: "008", Dark: "007"},
			FaintText:          lipgloss.AdaptiveColor{Light: "007", Dark: "249"},
			MainText:           lipgloss.AdaptiveColor{Light: "000", Dark: "015"},
			SecondaryText:      lipgloss.AdaptiveColor{Light: "244", Dark: "251"},
			SubleMainText:      lipgloss.AdaptiveColor{Light: "015", Dark: "236"},
			SuccessText:        lipgloss.AdaptiveColor{Light: "002", Dark: "002"},
			WarningText:        lipgloss.AdaptiveColor{Light: "001", Dark: "001"},

Let me know what you think!

[itspngu]

Works well on my default shell and Kitty, but on Konqueror it's somewhat borked. I'm not really passionate about this because I can make my own theme if I don't like the default now ;)

[dlvhdr]

Cool then! I'll change the ansi colors to mine as I prefer the borders not to be high contrast.
But I too will just use my custom theme :)

[dlvhdr]

Overall looks great!

[dlvhdr]

You can push whenever you're ready.
Thanks again!

[itspngu]

You can push whenever you're ready.

I'm not sure what you mean..? :D

[dlvhdr]

Ah push = merge

[itspngu]

I can't, it's set up so only you can :P

[dlvhdr]

Whoops ok then :)