package logging

import (
	"errors"
	"io"
	"os"
	"path/filepath"

	"code.icb4dc0.de/buildr/buildr/internal/ioutils"
)

type OutputSource string

const (
	OutputSourceStdout OutputSource = "stdout"
	OutputSourceStderr OutputSource = "stderr"
)

type LogFileNameFormatter interface {
	LogFileName(src OutputSource) string
}

type LogFileNameFormatterFunc func(src OutputSource) string

func (f LogFileNameFormatterFunc) LogFileName(src OutputSource) string {
	return f(src)
}

func NewTaskOutputSink(logsDirectory string, logToStdErr bool, formatter LogFileNameFormatter) (sink TaskOutputSink, err error) {
	fileSink := fileOutputSink{
		logToStdErr: logToStdErr,
	}

	if logToStdErr {
		if fileSink.stdOut, err = os.CreateTemp(os.TempDir(), "buildr-*.stdout.log"); err != nil {
			return nil, err
		}
		if fileSink.stdErr, err = os.CreateTemp(os.TempDir(), "buildr-*.stderr.log"); err != nil {
			return nil, err
		}
	} else {
		if fileSink.stdOut, err = os.Create(filepath.Join(logsDirectory, formatter.LogFileName(OutputSourceStdout))); err != nil {
			return nil, err
		}
		if fileSink.stdErr, err = os.Create(filepath.Join(logsDirectory, formatter.LogFileName(OutputSourceStderr))); err != nil {
			return nil, err
		}
	}

	return fileSink, nil
}

var _ TaskOutputSink = (*fileOutputSink)(nil)

type file interface {
	Name() string
	io.ReadWriter
	io.Seeker
	io.Closer
}

type fileOutputSink struct {
	stdOut      file
	stdErr      file
	logToStdErr bool
}

func (f fileOutputSink) StdOut() io.Writer {
	return f.stdOut
}

func (f fileOutputSink) StdErr() io.Writer {
	return f.stdErr
}

func (f fileOutputSink) Close() error {
	if f.logToStdErr {
		return errors.Join(
			f.copyToStdErrAndClose(f.stdOut),
			f.copyToStdErrAndClose(f.stdErr),
		)
	}

	return errors.Join(
		f.stdOut.Close(),
		f.stdErr.Close(),
	)
}

func (f fileOutputSink) copyToStdErrAndClose(src file) error {
	return AcquireStdErr(func(stdErr io.Writer) error {
		if _, err := src.Seek(0, 0); err != nil {
			return err
		}

		if _, err := ioutils.CopyWithPooledBuffer(stdErr, src); err != nil {
			return err
		}

		return errors.Join(src.Close(), os.Remove(src.Name()))
	})
}