package main

import (
  "errors"
  "fmt"
  "github.com/alyu/configparser"
  "os"
  "strconv"
)

type qwConfig struct {
  user, pass, dbName string 
  basePath string
  port int
}

func checkedSection(config *configparser.Configuration, name string) (*configparser.Section, error) {
  section, err := config.Section(name)
  if nil != err {
    fmt.Println("ERROR!  Could not locate section [" + name + "] in config file:", err)
    return nil, err
  }
  return section, nil
}

func checkedValue(section *configparser.Section, name string) (string, error) {
  if ! section.Exists(name) {
    return "", errors.New("ERROR!  Value named \"" + name + "\" not found in config file.")
  }

  value := section.ValueOf(name)
  return value, nil
}

// Note:  Will exit if config cannot be loaded
func GetConfig() (*qwConfig) {
  config, err := loadConfig()
  if nil != err {
    fmt.Println("FATAL!  Cannot load config.  Unable to continue.", err)
    os.Exit(1)
  }

  return config
}

func loadConfig() (*qwConfig, error) {
  // TODO:  Make the path to the config file configurable (environment variable?)
  // TODO:  Load the config file once, and cache the values for subsequent getConfig() calls

  const configFile = "quanlib.ini"

  config, err := configparser.Read(configFile)
  if nil != err {
    fmt.Println("ERROR!  Failed to read config file:", configFile, err)
    return nil, err
  }

  var section *configparser.Section

  // ------------------
  // Section:  database

  var dbName, user, pass string

  section, err = checkedSection(config, "database")
  if nil != err {
    return nil, err
  }

  dbName, err = checkedValue(section, "name")
  if nil != err {
    return nil, err
  }

  user, err = checkedValue(section, "user")
  if nil != err {
    return nil, err
  }

  pass, err = checkedValue(section, "pass")
  if nil != err {
    return nil, err
  }

  // --------------------
  // Section:  filesystem

  var basePath string

  section, err = checkedSection(config, "filesystem")
  if nil != err {
    return nil, err
  }

  basePath, err = checkedValue(section, "basePath")
  if nil != err {
    return nil, err
  }

  // -------------
  // Section:  web

  var port int
  var portStr string

  section, err = checkedSection(config, "web")
  if nil != err {
    return nil, err
  }

  portStr, err = checkedValue(section, "port")
  if nil != err {
    return nil, err
  }
  port, err = strconv.Atoi(portStr)
  if nil != err {
    return nil, err
  }

  return &qwConfig{ user:user, pass:pass, dbName:dbName, 
                    basePath:basePath,
                    port:port }, 
         nil 
}