package fog

import (
	"go.uber.org/zap"
	"go.uber.org/zap/buffer"
	"go.uber.org/zap/zapcore"
)

// encoder is a custom Zap encoder that is tailored for Google cloud
// monitoring
type encoder struct {
	zapcore.Encoder
}

func newEncoder(cfg zapcore.EncoderConfig) zapcore.Encoder {
	return encoder{zapcore.NewJSONEncoder(cfg)}
}

// Clone implements [go.uber.org/zap/zapcore.Encoder], preserving our custom
// encoder when the logger is cloned.
func (e encoder) Clone() zapcore.Encoder {
	return encoder{e.Encoder.Clone()}
}

// EncodeEntry implements [go.uber.org/zap/zapcore.Encoder].
func (e encoder) EncodeEntry(entry zapcore.Entry, fields []zapcore.Field) (*buffer.Buffer, error) {
	fields = append(fields, zap.Object(SourceKey, caller{&entry.Caller}))
	return e.Encoder.EncodeEntry(entry, fields)
}

// caller implements behavior for producing logs with caller information that
// Google cloud understands
type caller struct {
	*zapcore.EntryCaller
}

func (c caller) MarshalLogObject(enc zapcore.ObjectEncoder) error {
	enc.AddString("function", c.EntryCaller.Function)
	enc.AddString("file", c.EntryCaller.File)
	enc.AddInt("line", c.EntryCaller.Line)
	return nil
}

func encodeLevel() zapcore.LevelEncoder {
	return func(l zapcore.Level, enc zapcore.PrimitiveArrayEncoder) {
		switch {
		case l == 0:
			enc.AppendString(Info)
		case l < 0:
			// Everything below Info is Debug
			enc.AppendString(Debug)
		case l == zap.ErrorLevel:
			enc.AppendString(Error)
		}
	}
}