Button

package ui

import (
	"context"
	"io"
	"sort"

	"github.com/a-h/templ"
)

type ButtonVariant string

const (
	ButtonVariantDefault     ButtonVariant = "default"
	ButtonVariantDestructive ButtonVariant = "destructive"
	ButtonVariantOutline     ButtonVariant = "outline"
	ButtonVariantSecondary   ButtonVariant = "secondary"
	ButtonVariantGhost       ButtonVariant = "ghost"
	ButtonVariantLink        ButtonVariant = "link"
)

type ButtonSize string

const (
	ButtonSizeDefault ButtonSize = "default"
	ButtonSizeXS      ButtonSize = "xs"
	ButtonSizeSM      ButtonSize = "sm"
	ButtonSizeLG      ButtonSize = "lg"
	ButtonSizeIcon    ButtonSize = "icon"
	ButtonSizeIconXS  ButtonSize = "icon-xs"
	ButtonSizeIconSM  ButtonSize = "icon-sm"
	ButtonSizeIconLG  ButtonSize = "icon-lg"
)

type ButtonProps struct {
	DOMProps
	Label    string
	Leading  templ.Component
	Trailing templ.Component
	Variant  ButtonVariant
	Size     ButtonSize
	Type     string
	Disabled bool
	Href     string
}

var buttonVariantClasses = map[ButtonVariant]string{
	ButtonVariantDefault:     "bg-primary text-primary-foreground hover:bg-primary/90",
	ButtonVariantDestructive: "bg-destructive text-white hover:bg-destructive/90 focus-visible:ring-destructive/20 dark:bg-destructive/60 dark:focus-visible:ring-destructive/40",
	ButtonVariantOutline:     "border bg-background shadow-xs hover:bg-accent hover:text-accent-foreground dark:border-input dark:bg-input/30 dark:hover:bg-input/50",
	ButtonVariantSecondary:   "bg-secondary text-secondary-foreground hover:bg-secondary/80",
	ButtonVariantGhost:       "hover:bg-accent hover:text-accent-foreground dark:hover:bg-accent/50",
	ButtonVariantLink:        "text-primary underline-offset-4 hover:underline",
}

var buttonSizeClasses = map[ButtonSize]string{
	ButtonSizeDefault: "h-9 px-4 py-2 has-[>svg]:px-3",
	ButtonSizeXS:      "h-6 gap-1 rounded-md px-2 text-xs has-[>svg]:px-1.5 [&_svg:not([class*='size-'])]:size-3",
	ButtonSizeSM:      "h-8 gap-1.5 rounded-md px-3 has-[>svg]:px-2.5",
	ButtonSizeLG:      "h-10 rounded-md px-6 has-[>svg]:px-4",
	ButtonSizeIcon:    "size-9",
	ButtonSizeIconXS:  "size-6 rounded-md [&_svg:not([class*='size-'])]:size-3",
	ButtonSizeIconSM:  "size-8",
	ButtonSizeIconLG:  "size-10",
}

func buttonClasses(variant ButtonVariant, size ButtonSize, className string) string {
	if variant == "" {
		variant = ButtonVariantDefault
	}
	if size == "" {
		size = ButtonSizeDefault
	}

	base := "inline-flex shrink-0 items-center justify-center gap-2 rounded-md text-sm font-medium whitespace-nowrap transition-all outline-none focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50 disabled:pointer-events-none disabled:opacity-50 aria-invalid:border-destructive aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4"
	return cn(base, buttonVariantClasses[variant], buttonSizeClasses[size], className)
}

func Button(props ButtonProps) templ.Component {
	return templ.ComponentFunc(func(ctx context.Context, w io.Writer) error {
		ctx, slottedChildren := childrenFromContext(ctx)
		variant := props.Variant
		if variant == "" {
			variant = ButtonVariantDefault
		}
		size := props.Size
		if size == "" {
			size = ButtonSizeDefault
		}

		attrs := attrsFromDOMProps(props.DOMProps, "button", buttonClasses(variant, size, ""))
		attrs["data-variant"] = string(variant)
		attrs["data-size"] = string(size)

		tag := "button"
		if props.Element != "" {
			tag = props.Element
		} else if props.Href != "" {
			tag = "a"
		}

		if tag == "a" {
			attrs["href"] = props.Href
		} else {
			if props.Type == "" {
				attrs["type"] = "button"
			} else {
				attrs["type"] = props.Type
			}
			if props.Disabled {
				attrs["disabled"] = true
			}
		}

		children := templ.ComponentFunc(func(ctx context.Context, w io.Writer) error {
			if err := renderChildren(ctx, w, props.Leading); err != nil {
				return err
			}
			if props.Label != "" {
				if _, err := io.WriteString(w, templ.EscapeString(props.Label)); err != nil {
					return err
				}
			}
			if props.Label == "" && props.Leading == nil && props.Trailing == nil {
				if err := renderChildren(ctx, w, slottedChildren); err != nil {
					return err
				}
			}
			if err := renderChildren(ctx, w, props.Trailing); err != nil {
				return err
			}
			return nil
		})
		return renderElement(ctx, w, tag, attrs, children)
	})
}

func ButtonVariantNames() []string {
	names := make([]string, 0, len(buttonVariantClasses))
	for name := range buttonVariantClasses {
		names = append(names, string(name))
	}
	sort.Strings(names)
	return names
}