package main

import (
	"fmt"
	"net/url"
	"regexp"
	"strings"
	"time"

	"github.com/bitly/google_auth_proxy/providers"
)

// Configuration Options that can be set by Command Line Flag, or Config File
type Options struct {
	HttpAddress  string `flag:"http-address" cfg:"http_address"`
	RedirectUrl  string `flag:"redirect-url" cfg:"redirect_url"`
	ClientID     string `flag:"client-id" cfg:"client_id" env:"GOOGLE_AUTH_PROXY_CLIENT_ID"`
	ClientSecret string `flag:"client-secret" cfg:"client_secret" env:"GOOGLE_AUTH_PROXY_CLIENT_SECRET"`

	AuthenticatedEmailsFile string   `flag:"authenticated-emails-file" cfg:"authenticated_emails_file"`
	GoogleAppsDomains       []string `flag:"google-apps-domain" cfg:"google_apps_domains"`
	HtpasswdFile            string   `flag:"htpasswd-file" cfg:"htpasswd_file"`
	DisplayHtpasswdForm     bool     `flag:"display-htpasswd-form" cfg:"display_htpasswd_form"`
	CustomTemplatesDir      string   `flag:"custom-templates-dir" cfg:"custom_templates_dir"`

	CookieSecret    string        `flag:"cookie-secret" cfg:"cookie_secret" env:"GOOGLE_AUTH_PROXY_COOKIE_SECRET"`
	CookieDomain    string        `flag:"cookie-domain" cfg:"cookie_domain" env:"GOOGLE_AUTH_PROXY_COOKIE_DOMAIN"`
	CookieExpire    time.Duration `flag:"cookie-expire" cfg:"cookie_expire" env:"GOOGLE_AUTH_PROXY_COOKIE_EXPIRE"`
	CookieRefresh   time.Duration `flag:"cookie-refresh" cfg:"cookie_refresh" env:"GOOGLE_AUTH_PROXY_COOKIE_REFRESH"`
	CookieHttpsOnly bool          `flag:"cookie-https-only" cfg:"cookie_https_only"` // deprecated use cookie-secure
	CookieSecure    bool          `flag:"cookie-secure" cfg:"cookie_secure"`
	CookieHttpOnly  bool          `flag:"cookie-httponly" cfg:"cookie_httponly"`

	Upstreams       []string `flag:"upstream" cfg:"upstreams"`
	SkipAuthRegex   []string `flag:"skip-auth-regex" cfg:"skip_auth_regex"`
	PassBasicAuth   bool     `flag:"pass-basic-auth" cfg:"pass_basic_auth"`
	PassAccessToken bool     `flag:"pass-access-token" cfg:"pass_access_token"`
	PassHostHeader  bool     `flag:"pass-host-header" cfg:"pass_host_header"`

	// These options allow for other providers besides Google, with
	// potential overrides.
	Provider   string `flag:"provider" cfg:"provider"`
	LoginUrl   string `flag:"login-url" cfg:"login_url"`
	RedeemUrl  string `flag:"redeem-url" cfg:"redeem_url"`
	ProfileUrl string `flag:"profile-url" cfg:"profile_url"`
	Scope      string `flag:"scope" cfg:"scope"`

	RequestLogging bool `flag:"request-logging" cfg:"request_logging"`

	// internal values that are set after config validation
	redirectUrl   *url.URL
	proxyUrls     []*url.URL
	CompiledRegex []*regexp.Regexp
	provider      providers.Provider
}

func NewOptions() *Options {
	return &Options{
		HttpAddress:         "127.0.0.1:4180",
		DisplayHtpasswdForm: true,
		CookieHttpsOnly:     true,
		CookieSecure:        true,
		CookieHttpOnly:      true,
		CookieExpire:        time.Duration(168) * time.Hour,
		CookieRefresh:       time.Duration(0),
		PassBasicAuth:       true,
		PassAccessToken:     false,
		PassHostHeader:      true,
		RequestLogging:      true,
	}
}

func parseUrl(to_parse string, urltype string, msgs []string) (*url.URL, []string) {
	parsed, err := url.Parse(to_parse)
	if err != nil {
		return nil, append(msgs, fmt.Sprintf(
			"error parsing %s-url=%q %s", urltype, to_parse, err))
	}
	return parsed, msgs
}

func (o *Options) Validate() error {
	msgs := make([]string, 0)
	if len(o.Upstreams) < 1 {
		msgs = append(msgs, "missing setting: upstream")
	}
	if o.CookieSecret == "" {
		msgs = append(msgs, "missing setting: cookie-secret")
	}
	if o.ClientID == "" {
		msgs = append(msgs, "missing setting: client-id")
	}
	if o.ClientSecret == "" {
		msgs = append(msgs, "missing setting: client-secret")
	}

	o.redirectUrl, msgs = parseUrl(o.RedirectUrl, "redirect", msgs)

	for _, u := range o.Upstreams {
		upstreamUrl, err := url.Parse(u)
		if err != nil {
			msgs = append(msgs, fmt.Sprintf(
				"error parsing upstream=%q %s",
				upstreamUrl, err))
		}
		if upstreamUrl.Path == "" {
			upstreamUrl.Path = "/"
		}
		o.proxyUrls = append(o.proxyUrls, upstreamUrl)
	}

	for _, u := range o.SkipAuthRegex {
		CompiledRegex, err := regexp.Compile(u)
		if err != nil {
			msgs = append(msgs, fmt.Sprintf(
				"error compiling regex=%q %s", u, err))
		}
		o.CompiledRegex = append(o.CompiledRegex, CompiledRegex)
	}
	msgs = parseProviderInfo(o, msgs)

	if o.PassAccessToken {
		valid_cookie_secret_size := false
		for _, i := range []int{16, 24, 32} {
			if len(o.CookieSecret) == i {
				valid_cookie_secret_size = true
			}
		}
		if valid_cookie_secret_size == false {
			msgs = append(msgs, fmt.Sprintf(
				"cookie_secret must be 16, 24, or 32 bytes "+
					"to create an AES cipher when "+
					"pass_access_token == true, "+
					"but is %d bytes",
				len(o.CookieSecret)))
		}
	}

	if len(msgs) != 0 {
		return fmt.Errorf("Invalid configuration:\n  %s",
			strings.Join(msgs, "\n  "))
	}
	return nil
}

func parseProviderInfo(o *Options, msgs []string) []string {
	p := &providers.ProviderData{Scope: o.Scope}
	p.LoginUrl, msgs = parseUrl(o.LoginUrl, "login", msgs)
	p.RedeemUrl, msgs = parseUrl(o.RedeemUrl, "redeem", msgs)
	p.ProfileUrl, msgs = parseUrl(o.ProfileUrl, "profile", msgs)
	o.provider = providers.New(o.Provider, p)
	return msgs
}