Version history

@inject NavigationManager Navigation

@* A ruleset's version history: the versions down the side, and the one chosen compared with the
   one before it. The version and the layout are in the address (?v=, ?layout=), so every link
   works with JavaScript off; below 1024px the list goes above the diff. *@
<AppShell Variant="ShellVariant.Canvas">
    <AppHeader>
        <AppBrand Href="@To(null, null)" Icon="Lucide.ListChecks" Label="Acme Rules" />
        <Box Grow />
        <Avatar Name="Alan Turing" />
    </AppHeader>

    <AppMain>
        <Stack Gap="6" Padding="new() { Base = 4, Md = 8 }">
            <Stack Gap="1">
                <TextBlock Size="TextSize.Sm" Color="Color.Muted">Rulesets · Putaway</TextBlock>
                <Heading Level="1" Size="TextSize.Xl2">Version history</Heading>
            </Stack>

            <Grid Template='new() { Base = "minmax(0, 1fr)", Lg = "15rem minmax(0, 1fr)" }' Gap="6" Align="Align.Start">
                <Card Title="Versions" TitleLevel="2" Size="ControlSize.Sm">
                    <NavMenu Label="Versions">
                        @foreach (var version in RulesetVersions.All.Reverse())
                        {
                            <NavItem Href="@To(version == RulesetVersions.All[^1] ? null : version.Number, LayoutKey)" Badge="@(version.State == "Draft" ? "Draft" : null)">v@(version.Number) · @version.Note</NavItem>
                        }
                    </NavMenu>
                </Card>

                <Stack Gap="4">
                    <Row Gap="3" Align="Align.Center" Wrap>
                        <Stack Gap="1" Grow>
                            <Heading Level="2" Size="TextSize.Xl">v@(Shown.Number): @Shown.Note</Heading>
                            <TextBlock Size="TextSize.Sm" Color="Color.Muted">@Shown.State by @Shown.Author on @Shown.On.ToString("MMM d, yyyy")</TextBlock>
                        </Stack>
                        @if (Before is not null)
                        {
                            <Tabs Label="Layout" Size="ControlSize.Sm">
                                <TabLink Href="@To(ShownKey, null)" Label="Unified" />
                                <TabLink Href='@To(ShownKey, "split")' Label="Side by side" />
                            </Tabs>
                        }
                    </Row>
                    @if (Before is null)
                    {
                        <Diff OldText="" NewText="@Shown.Xml" Language="xml" Title="putaway.xml · first version" Fold="false" />
                    }
                    else
                    {
                        <Diff OldText="@Before.Xml" NewText="@Shown.Xml" Language="xml" Title="@($"putaway.xml · v{Before.Number} → v{Shown.Number}")"
                              Layout="@(LayoutKey == "split" ? DiffLayout.Split : DiffLayout.Unified)" />
                    }
                </Stack>
            </Grid>
        </Stack>
    </AppMain>
</AppShell>

@code {
    [SupplyParameterFromQuery(Name = "v")] private int? Version { get; set; }
    [SupplyParameterFromQuery(Name = "layout")] private string? LayoutKey { get; set; }

    // The newest unless the address names another.
    private RulesetVersion Shown => RulesetVersions.All.FirstOrDefault(v => v.Number == Version) ?? RulesetVersions.All[^1];

    // The version in the tabs' links: none for the newest, so a ?v= that names no version goes.
    private int? ShownKey => Shown == RulesetVersions.All[^1] ? null : Shown.Number;

    private RulesetVersion? Before => RulesetVersions.All.LastOrDefault(v => v.Number < Shown.Number);

    // Links within this example: its own address with the version and layout.
    private string To(int? version, string? layout) => Navigation.GetUriWithQueryParameters(new Dictionary<string, object?>
    {
        ["v"] = version,
        ["layout"] = layout,
    });
}