# v2.0.0

## Highlights

- Renamed the public Go package from `slog` to `sneklog` to avoid confusion with the standard library `log/slog` package.
- Moved the module path to `git.scuroneko.dev/scuroneko/sneklog/v2` for Go module major-version compatibility.
- Replaced fixed text writer settings with formatter-based output customization.
- Added built-in ANSI color support and removed the external `github.com/fatih/color` dependency tree.
- Formatters: a new way do display your logs!

## Breaking Changes

- Import paths must use the `/v2` module suffix:

```go
import "git.scuroneko.dev/scuroneko/sneklog/v2"
```

- Package references should use `sneklog` instead of `slog`.
- Removed `Logger.PrintTime` and `Logger.PrintTraceback`; configure output through writer formatters instead.
- Changed text writer constructors:
  - `CreateTextWriter(w, printTraceback, printTime)` is now `CreateTextWriter(w)`.
  - `CreateTextFileWriter(path, printTraceback, printTime)` is now `CreateTextFileWriter(path)`.
  - `CreateTextStdoutWriter(printTraceback, printTime)` is now `CreateTextStdoutWriter()`.
- Removed the old text formatting helpers: `BuildString`, `FormatTime`, `FormatTraceback`, and `FormatFullTraceback`.
- JSON `time` values are now formatted through the configured formatter and stored as strings in `LoggerJsonMessage`.

## Added

- `Formatter` for configurable message layouts, timestamp layouts, traceback layouts, separators, and color behavior.
- `DefaultTextFormatter` and `DefaultJsonFormatter` defaults for text and JSON writers.
- `LoggerTextWriter.SetFormatter` and `LoggerJsonWriter.SetFormatter`.
- Strftime-like timestamp format constants such as `RFC3339`, `Kitchen`, `DateTime`, `DateOnly`, and `TimeOnly`.
- Built-in color types and helpers:
  - `FgColor`, `BgColor`, and `Attribute`.
  - `ColorStringBuilder`.
  - Level color getters/setters on `LogLevel`.
- Tests covering formatter defaults, empty traceback placeholders, literal `%` sequences in messages, color controls, and JSON newline semantics.

## Changed

- Text output defaults to `DefaultTextFormatter` instead of the old hard-coded string builder.
- JSON output defaults to `DefaultJsonFormatter` and can now format the JSON `message` field through `Formatter`.
- Newline semantics are normalized before text and JSON formatting, so trailing `\n` controls record termination without becoming part of the message.
- Text color output is enabled by default only for stdout/stderr.
- Example code now demonstrates custom formatters and color configuration.
- Go dependencies were simplified by removing:
  - `github.com/fatih/color`
  - `github.com/mattn/go-colorable`
  - `github.com/mattn/go-isatty`
  - `golang.org/x/sys`

## Fixed

- `NewFormatter()` now returns a fresh copy instead of mutating `DefaultTextFormatter`.
- `Formatter.FormatMessage` no longer panics when called with an empty traceback.
- Placeholder-looking text inside log messages, such as `%L` or `%s`, is preserved literally.
- `SetColorOutput(false)` disables color output.
- `SetColorOnlyStdout(false)` allows color output for non-stdout writers.

## Migration

Before:

```go
import "git.scuroneko.dev/scuroneko/slog"

logger := slog.CreateLogger().
	Prefix("API").
	Level(slog.DEBUG).
	PrintTraceback(true)

text := logger.CreateTextStdoutWriter()
```

After:

```go
import sneklog "git.scuroneko.dev/scuroneko/sneklog/v2"

logger := sneklog.CreateLogger().
	Prefix("API").
	Level(sneklog.DEBUG)

formatter := sneklog.NewFormatter().
	SetFormat("%t [%L] %N: %m (%B)")

text := logger.CreateTextStdoutWriter().
	SetFormatter(formatter)
```

# v1.2.0

## Highlights

- Added message replacement with `Logger.AddReplacer(old, new)` for masking secrets or normalizing log output.
- Preserved the existing `LoggerWriter.Print(...any)` contract, so custom writers do not need a signature update.
- Improved JSON writer newline handling for messages that already end with `\n`.

## Added

- `Logger.AddReplacer(old, new)` appends a replacement rule that is applied before records are sent to writers.
- README and package GoDoc now document message replacement and include usage examples.
- Tests covering message type preservation for custom writers, JSON empty messages, and JSON trailing newline behavior.

## Fixed

- `LoggerJsonWriter.Print` no longer panics when called with no message arguments.
- `LoggerJsonWriter.Print` now treats a trailing newline at the end of the last message as newline semantics and does not include that newline in the JSON `message` field.
- Log messages keep their original argument types for custom writers when no replacement rules are configured.

## Changed

- Updated the example program to demonstrate `AddReplacer`.
- Updated dependencies:
  - `github.com/fatih/color` from `v1.18.0` to `v1.19.0`
  - `github.com/mattn/go-isatty` from `v0.0.20` to `v0.0.21`
  - `golang.org/x/sys` from `v0.42.0` to `v0.43.0`

## Compatibility

No breaking API changes are intended in this release. The public `LoggerWriter` interface continues to accept `messages ...any`.