package config

import (
	"fmt"
	"log"
	"os/exec"
	"strconv"
	"strings"

	"github.com/BurntSushi/toml"
)

// maybeInt is an integer that may be nil
type maybeInt struct {
	int
	bool
}

func (m maybeInt) empty() bool {
	return !m.bool
}

func (m maybeInt) value() int {
	return m.int
}

func initMaybeInt(value int) maybeInt {
	return maybeInt{value, true}
}

func (m *maybeInt) UnmarshalText(text []byte) error {
	var err error
	var i int64
	if text != nil {
		str := string(text)
		i, err = strconv.ParseInt(str, 10, 64)
		m.int = int(i)
		m.bool = true
	}
	return err
}

type fileConfig struct {
	Default         string    `toml:"default_account"`
	MailboxPath     string    `toml:"mailbox_path"`
	Accounts        []account `toml:"account"`
	DefaultMessages maybeInt  `toml:"default_messages"`
}

type account struct {
	Name            string          `toml:"name"`
	MailboxPath     string          `toml:"mailbox_path"`
	ConnectionInfo  *connectionInfo `toml:"connection"`
	ExcludedFolders []string        `toml:"excluded_folders"`
	Messages        maybeInt        `toml:"messages"`
}

type connectionInfo struct {
	Host         string       `toml:"hostname"`
	Port         int          `toml:"port"`
	Username     string       `toml:"username"`
	PasswordExec *ShellScript `toml:"password_exec"`
	PasswordFile string       `toml:"password_file"`
	Password     string       `toml:"password"`
}

func (c *connectionInfo) String() string {
	var res string
	res += "{"
	res += fmt.Sprintf("Host: %s, ", c.Host)
	res += fmt.Sprintf("Port: %d, ", c.Port)
	res += fmt.Sprintf("Username: %s, ", c.Username)
	res += fmt.Sprintf("Password: **********, ")
	res += fmt.Sprintf("PasswordFile: %s, ", c.PasswordFile)
	res += fmt.Sprintf("PasswordExec: %s}", c.PasswordExec)
	return res
}

// ShellScript might be either:
//  - the path to an executable
//  - an executable in path
//  - a shell command with its argument
// all these must return on stdout the password after successful execution.
type ShellScript struct {
	Executable string
}

func (s *ShellScript) UnmarshalText(text []byte) error {
	s.Executable = string(text)
	return nil
}

func (s *ShellScript) String() string {
	return s.Executable
}

// Present indicates if the value has been filled in into the config
func (s *ShellScript) Present() bool {
	if s != nil {
		return s.Executable != ""
	}
	return false
}

// Run tries to execute the command, first looking for a corresponding executable and
// invoking it, then invoking the string as a command followed by its parameters.
func (s *ShellScript) Run() (string, error) {
	if path, err := exec.LookPath(s.Executable); err == nil {
		return doExec(path)
	}
	parts := strings.Split(s.Executable, " ")
	return doExec(parts[0], parts[1:]...)
}

func doExec(path string, args ...string) (string, error) {
	cmd := exec.Command(path, args...)
	out, err := cmd.Output()
	if err != nil {
		log.Println("Error running:", cmd)
		return "", err
	}
	return string(out), nil
}

// parseFile reads the given config file and, if succeeding, returns a *FileConfig.
func parseFile(path string) (*fileConfig, error) {
	newConfig := fileConfig{}
	_, err := toml.DecodeFile(path, &newConfig)
	return &newConfig, err
}