package mailstuff

import (
	"bytes"
	"io"
	"net/mail"
)

func ReadMBox(r io.Reader) ([]*mail.Message, error) {
	rest, err := io.ReadAll(r)
	if err != nil {
		return nil, err
	}

	const terminator = "\nFrom "

	var parts [][]byte
	for {
		pos := bytes.Index(rest, []byte(terminator))
		if pos < 0 {
			parts = append(parts, rest)
			break
		}
		parts = append(parts, rest[:pos+1])
		rest = rest[pos+1:]
	}

	ret := make([]*mail.Message, len(parts))
	for i := range len(parts) {
		msg, err := mail.ReadMessage(bytes.NewReader(parts[i]))
		if err != nil {
			return nil, err
		}
		ret[i] = msg
	}

	return ret, nil
}