package main

import (
	"path/filepath"
	"strings"
	"bufio"
	"fmt"
	"io"
	"os"
)

func getBaseConfigDir() (path string) {
	path = os.Getenv("XDG_CONFIG_HOME")
	if path != "" {
		return
	}
	path = os.Getenv("APPDATA")
	if path != "" {
		return
	}
	if os.Getenv("HOME") != "" {
		return filepath.Join(os.Getenv("HOME"), ".config")
	} else {
		return filepath.Join(filepath.Base(os.Args[0]), "config")
	}
}

func getConfigDir() string {
	return filepath.Join(getBaseConfigDir(), "talk")
}

func (a *application) executeScript(rd io.Reader) error {
	var (
		command strings.Builder
		br = bufio.NewReader(rd)
	)
	for {
		command.Reset()
		command.WriteRune('/')
		for {
			c, _, err := br.ReadRune()
			if err == io.EOF {
				break
			}
			if err != nil {
				return fmt.Errorf("error reading configuration: %s", err)
			}
			if c == '/' && command.Len() == 1 {
				continue
			}
			if c == '\\' {
				command.WriteRune(c)
				c, _, _ = br.ReadRune()
			} else if c == '#' {
				for c != '\n' {
					c, _, err = br.ReadRune()
					if err != nil {
						break
					}
				}
			} else if c == '\n' {
				break
			}
			command.WriteRune(c)
		}
		if strings.TrimSpace(command.String()) != "" {
			a.processCommand(command.String())
		}
		_, err := br.Peek(1)
		if err == io.EOF {
			break
		}
	}
	return nil
}

func (a *application) executeConfig(name string) error {
	file, err := os.Open(filepath.Join(getConfigDir(), name))
	if err != nil {
		return fmt.Errorf("error reading configuration: %s", err)
	}
	return a.executeScript(file)
}

func (a *application) executeConfigOptional(name string) (err error) {
	err = a.executeConfig(name)
	if os.IsNotExist(err) {
		return nil
	}
	return
}