package sneklog

import (
	"errors"
	"fmt"
	"io"
	"strings"
)

// LogLevel describes a logging severity.
type LogLevel struct {
	n uint8
	t string

	fg    FgColor
	fg256 FgColor256
	fgRgb FgColorRGB

	bg    BgColor
	bg256 BgColor256
	bgRgb BgColorRGB

	attrs []Attribute
}

// NewLogLevel creates a log level without predefined colors.
func NewLogLevel(index uint8, name string) LogLevel {
	return LogLevel{n: index, t: name, attrs: []Attribute{}}
}

// NewLogLevelWithColors creates a log level with ANSI foreground and background colors.
func NewLogLevelWithColors(index uint8, name string, fg FgColor, bg BgColor) LogLevel {
	return LogLevel{n: index, t: name, fg: fg, bg: bg, attrs: []Attribute{}}
}

// GetName returns the lowercase textual representation of the level.
func (l *LogLevel) GetName() string { return l.t }

// SetFgColor sets the ANSI foreground color and clears other foreground color modes.
// Deprecated: use SetForegroundColor. This method will be removed in v3.
func (l *LogLevel) SetFgColor(color FgColor) *LogLevel {
	return l.SetForegroundColor(color)
}

// GetFgColor returns the ANSI foreground color for the level.
// Deprecated: use GetForegroundColor. This method will be removed in v3.
func (l *LogLevel) GetFgColor() FgColor { return l.GetForegroundColor() }

// SetForegroundColor sets the ANSI foreground color and clears other foreground color modes.
func (l *LogLevel) SetForegroundColor(color FgColor) *LogLevel {
	l.fg = color
	l.fg256 = 0
	l.fgRgb = nil
	return l
}

// GetForegroundColor returns the ANSI foreground color for the level.
func (l *LogLevel) GetForegroundColor() FgColor { return l.fg }

// SetForeground256Color sets the 256-color foreground and clears other foreground color modes.
func (l *LogLevel) SetForeground256Color(color FgColor256) *LogLevel {
	l.fg = 0
	l.fg256 = color
	l.fgRgb = nil
	return l
}

// GetForeground256Color returns the configured 256-color foreground value.
func (l *LogLevel) GetForeground256Color() FgColor256 { return l.fg256 }

// SetForegroundRGB sets the RGB foreground color and clears other foreground color modes.
func (l *LogLevel) SetForegroundRGB(r, g, b uint8) *LogLevel {
	l.fg = 0
	l.fg256 = 0
	l.fgRgb = FgColorRGB{r, g, b}
	return l
}

// GetForegroundRGB returns the configured RGB foreground value.
func (l *LogLevel) GetForegroundRGB() FgColorRGB { return l.fgRgb }

// SetBgColor sets the ANSI background color and clears other background color modes.
// Deprecated: use SetBackgroundColor. This method will be removed in v3.
func (l *LogLevel) SetBgColor(color BgColor) *LogLevel {
	return l.SetBackgroundColor(color)
}

// GetBgColor returns the ANSI background color for the level.
// Deprecated: use GetBackgroundColor. This method will be removed in v3.
func (l *LogLevel) GetBgColor() BgColor { return l.GetBackgroundColor() }

// SetBackgroundColor sets the ANSI background color and clears other background color modes.
func (l *LogLevel) SetBackgroundColor(color BgColor) *LogLevel {
	l.bg = color
	l.bg256 = 0
	l.bgRgb = nil
	return l
}

// GetBackgroundColor returns the ANSI background color for the level.
func (l *LogLevel) GetBackgroundColor() BgColor { return l.bg }

// SetBackground256Color sets the 256-color background and clears other background color modes.
func (l *LogLevel) SetBackground256Color(color BgColor256) *LogLevel {
	l.bg = 0
	l.bg256 = color
	l.bgRgb = nil
	return l
}

// GetBackground256Color returns the configured 256-color background value.
func (l *LogLevel) GetBackground256Color() BgColor256 { return l.bg256 }

// SetBackgroundRGB sets the RGB background color and clears other background color modes.
func (l *LogLevel) SetBackgroundRGB(r, g, b uint8) *LogLevel {
	l.bg = 0
	l.bg256 = 0
	l.bgRgb = BgColorRGB{r, g, b}
	return l
}

// GetBackgroundRGB returns the configured RGB background value.
func (l *LogLevel) GetBackgroundRGB() BgColorRGB { return l.bgRgb }

// AddAttribute appends an ANSI text attribute to the level.
func (l *LogLevel) AddAttribute(a Attribute) *LogLevel {
	l.attrs = append(l.attrs, a)
	return l
}

// RemoveAttribute removes all matching ANSI text attributes from the level.
func (l *LogLevel) RemoveAttribute(a Attribute) *LogLevel {
	attrs := make([]Attribute, 0)
	for _, attr := range l.attrs {
		if attr != a {
			attrs = append(attrs, attr)
		}
	}
	l.attrs = attrs
	return l
}

// SetAttributes replaces the level attributes with a copy of the provided slice.
func (l *LogLevel) SetAttributes(a []Attribute) *LogLevel {
	attrs := make([]Attribute, len(a))
	copy(attrs, a)
	l.attrs = attrs
	return l
}

// GetAttributes returns a copy of the configured ANSI text attributes.
func (l *LogLevel) GetAttributes() []Attribute {
	attrs := make([]Attribute, len(l.attrs))
	copy(attrs, l.attrs)
	return attrs
}

// MethodTraceback describes a single stack frame attached to a log entry.
type MethodTraceback struct {
	Method    string `json:"method"`
	Filename  string `json:"filename"`
	Line      int    `json:"line"`
	Signature string `json:"signature"`
	FullPath  string `json:"fullPath"`
}

// Predefined log levels.
var (
	INFO  = NewLogLevelWithColors(0, "info", FgWhite, BgNone)
	WARN  = NewLogLevelWithColors(1, "warn", FgHiYellow, BgNone)
	ERROR = NewLogLevelWithColors(2, "error", FgHiRed, BgNone)
	FATAL = NewLogLevelWithColors(3, "fatal", FgRed, BgNone)
	DEBUG = NewLogLevelWithColors(4, "debug", FgGreen, BgNone)
)

// Logger routes log records to one or more configured writers.
type Logger struct {
	prefix    string
	level     LogLevel
	writers   []LoggerWriter
	replacers []replacer

	jsonPretty bool
}

// CreateLogger creates a logger with default settings.
// Deprecated: use NewLogger. This method will be removed in v3.
func CreateLogger() *Logger {
	return &Logger{
		prefix: "LOG",
		level:  FATAL,
	}
}

// NewLogger creates a logger with default settings.
func NewLogger() *Logger {
	return &Logger{
		prefix: "LOG",
		level:  FATAL,
	}
}

// Prefix sets the record prefix and returns the logger for chaining.
// Deprecated: use SetName. This method will be removed in v3.
func (l *Logger) Prefix(prefix string) *Logger {
	l.prefix = prefix
	return l
}

// SetName sets the record prefix and returns the logger for chaining.
func (l *Logger) SetName(name string) *Logger {
	l.prefix = name
	return l
}

// Level sets the maximum enabled level and returns the logger for chaining.
// Deprecated: use SetLevel. This method will be removed in v3.
func (l *Logger) Level(level LogLevel) *Logger {
	l.level = level
	return l
}

// SetLevel sets the maximum enabled level and returns the logger for chaining.
func (l *Logger) SetLevel(level LogLevel) *Logger {
	l.level = level
	return l
}

// JsonPretty enables or disables indented JSON output for JSON writers created by the logger.
// Deprecated: use SetJSONPretty. This method will be removed in v3.
func (l *Logger) JsonPretty(b bool) *Logger {
	l.jsonPretty = b
	return l
}

// SetJSONPretty enables or disables indented output for JSON writers created by the logger.
func (l *Logger) SetJSONPretty(b bool) *Logger {
	l.jsonPretty = b
	return l
}

// AddWriters appends multiple writers to the logger.
func (l *Logger) AddWriters(writers ...LoggerWriter) *Logger {
	l.writers = append(l.writers, writers...)
	return l
}

// AddWriter appends a single writer to the logger.
// Deprecated: use AddWriters. This method will be removed in v3.
func (l *Logger) AddWriter(writer LoggerWriter) *Logger {
	l.writers = append(l.writers, writer)
	return l
}

// AddReplacer appends a message replacer and returns the logger for chaining.
//
// Replacement rules are applied before records are passed to writers. Empty old
// values are ignored because replacing an empty string would insert the
// replacement between every UTF-8 sequence.
func (l *Logger) AddReplacer(old, new string) *Logger {
	if old == "" {
		return l
	}
	r := replacer{old: old, new: new}
	l.replacers = append(l.replacers, r)
	return l
}

// Close closes all owned writers and returns a joined error, if any.
func (l *Logger) Close() error {
	var errs []error
	for _, writer := range l.writers {
		if writer == nil {
			continue
		}
		err := writer.Close()
		if err != nil {
			errs = append(errs, err)
		}
	}
	l.writers = nil
	return errors.Join(errs...)
}

// CreateTextWriter wraps an external writer with the logger text settings.
func (l *Logger) CreateTextWriter(w io.Writer) *LoggerTextWriter { return CreateTextWriter(w) }

// CreateTextStdoutWriter creates a non-owning text writer for os.Stdout.
func (l *Logger) CreateTextStdoutWriter() *LoggerTextWriter { return CreateTextStdoutWriter() }

// CreateTextFileWriter creates an owning text writer for a file.
func (l *Logger) CreateTextFileWriter(filename string) (*LoggerTextWriter, error) {
	return CreateTextFileWriter(filename)
}

// CreateJsonWriter wraps an external writer with the logger JSON settings.
func (l *Logger) CreateJsonWriter(w io.Writer) *LoggerJsonWriter {
	return CreateJsonWriter(w, l.jsonPretty)
}

// CreateJsonStdoutWriter creates a non-owning JSON writer for os.Stdout.
func (l *Logger) CreateJsonStdoutWriter() *LoggerJsonWriter {
	return CreateJsonStdoutWriter(l.jsonPretty)
}

// CreateJsonFileWriter creates an owning JSON writer for a file.
func (l *Logger) CreateJsonFileWriter(filename string) (*LoggerJsonWriter, error) {
	return CreateJsonFileWriter(filename, l.jsonPretty)
}

type replacer struct {
	old string
	new string
}

func (r replacer) replace(s string) string { return strings.ReplaceAll(s, r.old, r.new) }
func (l *Logger) replace(s string) string {
	out := s
	for _, repl := range l.replacers {
		out = repl.replace(out)
	}
	return out
}
func (l *Logger) replaceAll(messages ...any) []any {
	if len(l.replacers) == 0 {
		return messages
	}
	out := make([]any, len(messages))
	for i, msg := range messages {
		out[i] = l.replace(fmt.Sprint(msg))
	}
	return out
}