package bonfire

import (
	"strconv"
	"strings"
)

// helpUsage is the usage line of a command in help and the JSON listing:
// the name, its arguments and [options]; passthrough commands end with
// [--] <args...> because everything after the name reaches them unparsed.
func helpUsage(c Command) string {
	u := commandUsage(c) + " [options]"
	if c.Passthrough {
		u += " [--] <args...>"
	}
	return u
}

// optionLabel is the left column of a flag: "-x, --name=NAME" for value
// flags, "--name" for bare flags, indented four spaces without shorthand.
func optionLabel(f Flag) string {
	label := "    "
	if f.Shorthand != "" {
		label = "-" + f.Shorthand + ", "
	}
	label += "--" + f.Name
	if !f.Bare {
		label += "=" + strings.ToUpper(strings.ReplaceAll(f.Name, "-", "_"))
	}
	return label
}

// optionDetail is a flag's description followed by its default and the
// repeatable marker.
func optionDetail(f Flag) string {
	parts := []string{}
	if f.Description != "" {
		parts = append(parts, f.Description)
	}
	if f.Default != "" && !f.Bare {
		if _, err := strconv.Atoi(f.Default); err == nil {
			parts = append(parts, "[default: "+f.Default+"]")
		} else {
			parts = append(parts, "[default: "+strconv.Quote(f.Default)+"]")
		}
	}
	if f.Repeatable {
		parts = append(parts, "(multiple values allowed)")
	}
	return strings.Join(parts, " ")
}

// renderHelp writes a command's help in the Artisan layout: Description,
// Usage, Arguments, Options with defaults, Global options, Help (the long
// text) and Examples, each section present only when it has content.
func (st *rootState) renderHelp(c Command, g Globals) error {
	p := DefaultPalette()
	var b strings.Builder
	section := func(title string) {
		if b.Len() > 0 {
			b.WriteString("\n")
		}
		b.WriteString(p.Header.Render(title+":") + "\n")
	}

	if c.Description != "" {
		section("Description")
		b.WriteString("  " + c.Description + "\n")
	}
	section("Usage")
	b.WriteString("  " + helpUsage(c) + "\n")

	width := 0
	for _, a := range c.Args {
		width = max(width, len(a.Name))
	}
	for _, f := range c.Flags {
		width = max(width, len(optionLabel(f)))
	}
	row := func(label, detail string) {
		line := "  " + p.Success.Render(label)
		if detail != "" {
			line += strings.Repeat(" ", width-len(label)+2) + detail
		}
		b.WriteString(line + "\n")
	}
	if len(c.Args) > 0 {
		section("Arguments")
		for _, a := range c.Args {
			row(a.Name, a.Description)
		}
	}
	if len(c.Flags) > 0 {
		section("Options")
		for _, f := range c.Flags {
			row(optionLabel(f), optionDetail(f))
		}
	}
	section("Global options")
	writeGlobalOptions(&b, p)
	if long := strings.TrimSpace(c.Long); long != "" {
		section("Help")
		for _, line := range strings.Split(long, "\n") {
			if strings.TrimSpace(line) == "" {
				b.WriteString("\n")
				continue
			}
			b.WriteString("  " + line + "\n")
		}
	}
	if len(c.Examples) > 0 {
		section("Examples")
		bin := usageName(st.name)
		for i, e := range c.Examples {
			if i > 0 {
				b.WriteString("\n")
			}
			if e.Description != "" {
				b.WriteString("  " + p.Muted.Render("# "+e.Description) + "\n")
			}
			b.WriteString("  " + bin + " " + e.Command + "\n")
		}
	}
	return writeStyled(st.out, g, b.String())
}