//go:build dev
// +build dev

package build

import (
	"fmt"
	"strings"

	btclogv1 "github.com/btcsuite/btclog"
	"github.com/btcsuite/btclog/v2"
)

const (
	resetSeq = "0"
	boldSeq  = "1"
	faintSeq = "2"
	esc      = '\x1b'
	csi      = string(esc) + "["

	callSiteOff   = "off"
	callSiteShort = "short"
	callSiteLong  = "long"
)

// LogConfig holds logging configuration options.
//
//nolint:lll
type LogConfig struct {
	Console *consoleLoggerCfg `group:"console" namespace:"console" description:"The logger writing to stdout and stderr."`
	File    *LoggerConfig     `group:"file" namespace:"file" description:"The logger writing to LND's standard log file."`
}

// DefaultLogConfig returns the default logging config options.
func DefaultLogConfig() *LogConfig {
	return &LogConfig{
		Console: &consoleLoggerCfg{
			LoggerConfig: LoggerConfig{
				CallSite: callSiteShort,
			},
		},
		File: &LoggerConfig{
			CallSite: callSiteOff,
		},
	}
}

// LoggerConfig holds options for a particular logger.
//
//nolint:lll
type LoggerConfig struct {
	Disable      bool   `long:"disable" description:"Disable this logger."`
	NoTimestamps bool   `long:"no-timestamps" description:"Omit timestamps from log lines."`
	CallSite     string `long:"call-site" description:"Include the call-site of each log line." choice:"off" choice:"short" choice:"long"`
}

// HandlerOptions returns the set of btclog.HandlerOptions that the state of the
// config struct translates to.
func (cfg *LoggerConfig) HandlerOptions() []btclog.HandlerOption {
	opts := []btclog.HandlerOption{
		// The default skip depth used by the logging library is 6 but
		// since we wrap the logging handlers with another level of
		// abstraction with the handlerSet, we increase the skip depth
		// to 7 here.
		btclog.WithCallSiteSkipDepth(7),
	}

	if cfg.NoTimestamps {
		opts = append(opts, btclog.WithNoTimestamp())
	}

	switch cfg.CallSite {
	case callSiteShort:
		opts = append(opts, btclog.WithCallerFlags(btclog.Lshortfile))
	case callSiteLong:
		opts = append(opts, btclog.WithCallerFlags(btclog.Llongfile))
	}

	return opts
}

// consoleLoggerCfg extends the LoggerConfig struct by adding a Color option
// which is only available for a console logger.
//
//nolint:lll
type consoleLoggerCfg struct {
	LoggerConfig
	Style bool `long:"style" description:"If set, the output will be styled with color and fonts"`
}

// HandlerOptions returns the set of btclog.HandlerOptions that the state of the
// config struct translates to.
func (cfg *consoleLoggerCfg) HandlerOptions() []btclog.HandlerOption {
	opts := cfg.LoggerConfig.HandlerOptions()

	if !cfg.Style {
		return opts
	}

	return append(
		opts, btclog.WithStyledLevel(
			func(l btclogv1.Level) string {
				return styleString(
					fmt.Sprintf("[%s]", l),
					boldSeq,
					string(ansiColoSeq(l)),
				)
			},
		),
		btclog.WithStyledCallSite(
			func(file string, line int) string {
				str := fmt.Sprintf("%s:%d", file, line)

				return styleString(str, faintSeq)
			},
		),
		btclog.WithStyledKeys(func(key string) string {
			return styleString(key, faintSeq)
		}),
	)
}

func styleString(s string, styles ...string) string {
	if len(styles) == 0 {
		return s
	}

	seq := strings.Join(styles, ";")
	if seq == "" {
		return s
	}

	return fmt.Sprintf("%s%sm%s%sm", csi, seq, s, csi+resetSeq)
}

type ansiColorSeq string

const (
	ansiColorSeqDarkTeal  ansiColorSeq = "38;5;30"
	ansiColorSeqDarkBlue  ansiColorSeq = "38;5;63"
	ansiColorSeqLightBlue ansiColorSeq = "38;5;86"
	ansiColorSeqYellow    ansiColorSeq = "38;5;192"
	ansiColorSeqRed       ansiColorSeq = "38;5;204"
	ansiColorSeqPink      ansiColorSeq = "38;5;134"
)

func ansiColoSeq(l btclogv1.Level) ansiColorSeq {
	switch l {
	case btclog.LevelTrace:
		return ansiColorSeqDarkTeal
	case btclog.LevelDebug:
		return ansiColorSeqDarkBlue
	case btclog.LevelWarn:
		return ansiColorSeqYellow
	case btclog.LevelError:
		return ansiColorSeqRed
	case btclog.LevelCritical:
		return ansiColorSeqPink
	default:
		return ansiColorSeqLightBlue
	}
}