package color

import (
	"fmt"
	"strings"
)

const Reset = "\033[0m"

var ansiFg = map[string]int{
	"black":   30,
	"red":     31,
	"green":   32,
	"yellow":  33,
	"blue":    34,
	"magenta": 35,
	"cyan":    36,
	"white":   37,
}

var ansiBg = map[string]int{
	"black":   40,
	"red":     41,
	"green":   42,
	"yellow":  43,
	"blue":    44,
	"magenta": 45,
	"cyan":    46,
	"white":   47,
}

var ansiBrightFg = map[string]int{
	"bright_black":   90,
	"bright_red":     91,
	"bright_green":   92,
	"bright_yellow":  93,
	"bright_blue":    94,
	"bright_magenta": 95,
	"bright_cyan":    96,
	"bright_white":   97,
}

var ansiBrightBg = map[string]int{
	"bright_black":   100,
	"bright_red":     101,
	"bright_green":   102,
	"bright_yellow":  103,
	"bright_blue":    104,
	"bright_magenta": 105,
	"bright_cyan":    106,
	"bright_white":   107,
}

var xtermFg = map[string]int{
	"black":           0,
	"red":             1,
	"green":           2,
	"yellow":          3,
	"blue":            4,
	"magenta":         5,
	"cyan":            6,
	"white":           7,
	"bright_black":    8,
	"bright_red":      9,
	"bright_green":    10,
	"bright_yellow":   11,
	"bright_blue":     12,
	"bright_magenta":  13,
	"bright_cyan":     14,
	"bright_white":    15,
}

var ansiStyles = map[string]string{
	"bold":      "\033[1m",
	"dim":       "\033[2m",
	"italic":    "\033[3m",
	"underline": "\033[4m",
}

func Fg(mode, name string) string {
	if mode == "none" || mode == "" {
		return ""
	}
	if mode == "xterm256" {
		if c, ok := xtermFg[name]; ok {
			return fmt.Sprintf("\033[38;5;%dm", c)
		}
		return ""
	}
	if c, ok := ansiFg[name]; ok {
		return fmt.Sprintf("\033[%dm", c)
	}
	if c, ok := ansiBrightFg[name]; ok {
		return fmt.Sprintf("\033[%dm", c)
	}
	return ""
}

func Bg(mode, name string) string {
	if mode == "none" || mode == "" {
		return ""
	}
	if mode == "xterm256" {
		if c, ok := xtermFg[name]; ok {
			return fmt.Sprintf("\033[48;5;%dm", c)
		}
		return ""
	}
	if c, ok := ansiBg[name]; ok {
		return fmt.Sprintf("\033[%dm", c)
	}
	if c, ok := ansiBrightBg[name]; ok {
		return fmt.Sprintf("\033[%dm", c)
	}
	return ""
}

func Style(name string) string {
	if s, ok := ansiStyles[name]; ok {
		return s
	}
	return ""
}

type ColorSpec struct {
	Fg        string
	Bg        string
	Bold      bool
	Dim       bool
	Italic    bool
	Underline bool
}

func Parse(input string) ColorSpec {
	var spec ColorSpec
	for _, token := range strings.Fields(input) {
		switch {
		case token == "bold":
			spec.Bold = true
		case token == "dim":
			spec.Dim = true
		case token == "italic":
			spec.Italic = true
		case token == "underline":
			spec.Underline = true
		case strings.HasPrefix(token, "fg="):
			spec.Fg = strings.TrimPrefix(token, "fg=")
		case strings.HasPrefix(token, "bg="):
			spec.Bg = strings.TrimPrefix(token, "bg=")
		}
	}
	return spec
}

func (s ColorSpec) Empty() bool {
	return s.Fg == "" && s.Bg == "" && !s.Bold && !s.Dim && !s.Italic && !s.Underline
}

func Render(mode string, spec ColorSpec, text string) string {
	if mode == "none" || mode == "" || spec.Empty() {
		return text
	}
	var codes []string
	if spec.Bold {
		codes = append(codes, Style("bold"))
	}
	if spec.Dim {
		codes = append(codes, Style("dim"))
	}
	if spec.Italic {
		codes = append(codes, Style("italic"))
	}
	if spec.Underline {
		codes = append(codes, Style("underline"))
	}
	if spec.Fg != "" {
		codes = append(codes, Fg(mode, spec.Fg))
	}
	if spec.Bg != "" {
		codes = append(codes, Bg(mode, spec.Bg))
	}
	if len(codes) == 0 {
		return text
	}
	return strings.Join(codes, "") + text + Reset
}