package bonfire

import (
	"io"
	"os"
	"strings"

	"charm.land/lipgloss/v2"
	"github.com/charmbracelet/colorprofile"
)

// ColorMode selects how console output decides on color: from the terminal
// and the environment, always, or never.
type ColorMode int

const (
	// ColorAuto colors output when the writer is a terminal and the
	// environment allows it (NO_COLOR and TERM=dumb disable color,
	// FORCE_COLOR enables it on any writer).
	ColorAuto ColorMode = iota
	// ColorAlways colors output whatever the writer is (--ansi).
	ColorAlways
	// ColorNever writes no escape codes at all (--no-ansi).
	ColorNever
)

// Palette is the shared console look: the status styles of list, help,
// widgets and log lines. Render through a writer that applies the color
// profile (DetectProfile), because lipgloss always emits ANSI codes.
type Palette struct {
	// Success marks completed work (green).
	Success lipgloss.Style
	// Current marks the item in progress and informational lines (cyan).
	Current lipgloss.Style
	// Warning marks warnings (yellow).
	Warning lipgloss.Style
	// Error marks failures (red).
	Error lipgloss.Style
	// ErrorBold marks fatal failures and error levels (bold red).
	ErrorBold lipgloss.Style
	// Muted marks secondary detail such as times and keys (gray).
	Muted lipgloss.Style
	// Header marks headings and names (bold).
	Header lipgloss.Style
}

// DefaultPalette returns the console palette, ported from SSU's status
// styles: green success, cyan current, yellow warning, red and bold red
// errors, gray (240) muted text and bold headers.
func DefaultPalette() Palette {
	return Palette{
		Success:   lipgloss.NewStyle().Foreground(lipgloss.Color("2")),
		Current:   lipgloss.NewStyle().Foreground(lipgloss.Color("6")),
		Warning:   lipgloss.NewStyle().Foreground(lipgloss.Color("3")),
		Error:     lipgloss.NewStyle().Foreground(lipgloss.Color("1")),
		ErrorBold: lipgloss.NewStyle().Foreground(lipgloss.Color("1")).Bold(true),
		Muted:     lipgloss.NewStyle().Foreground(lipgloss.Color("240")),
		Header:    lipgloss.NewStyle().Bold(true),
	}
}

// DetectProfile returns the color profile for console output written to w.
// ColorNever gives colorprofile.NoTTY (no escape codes at all). ColorAlways
// gives the detected profile raised to at least 256 colors. ColorAuto treats
// a non-empty FORCE_COLOR as ColorAlways unless NO_COLOR is set or TERM is
// dumb, and otherwise detects the profile from w and environ, which honours
// NO_COLOR and TERM=dumb. A nil environ means os.Environ().
func DetectProfile(w io.Writer, mode ColorMode, environ []string) colorprofile.Profile {
	if mode == ColorNever {
		return colorprofile.NoTTY
	}
	if environ == nil {
		environ = os.Environ()
	}
	if mode == ColorAuto && forceColor(environ) {
		mode = ColorAlways
	}
	p := colorprofile.Detect(w, environ)
	if mode == ColorAlways && p < colorprofile.ANSI256 {
		p = colorprofile.ANSI256
	}
	return p
}

func forceColor(environ []string) bool {
	if envValue(environ, "NO_COLOR") != "" || envValue(environ, "TERM") == "dumb" {
		return false
	}
	return envValue(environ, "FORCE_COLOR") != ""
}

func envValue(environ []string, key string) string {
	for i := len(environ) - 1; i >= 0; i-- {
		k, v, ok := strings.Cut(environ[i], "=")
		if ok && k == key {
			return v
		}
	}
	return ""
}