// Copyright 2017 Frédéric Guillot. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.

package config

import (
	"net/url"
	"os"
	"strconv"
	"strings"

	"github.com/miniflux/miniflux/logger"
)

const (
	defaultBaseURL          = "http://localhost"
	defaultDatabaseURL      = "postgres://postgres:postgres@localhost/miniflux2?sslmode=disable"
	defaultWorkerPoolSize   = 5
	defaultPollingFrequency = 60
	defaultBatchSize        = 10
	defaultDatabaseMaxConns = 20
	defaultListenAddr       = "127.0.0.1:8080"
	defaultCertFile         = ""
	defaultKeyFile          = ""
	defaultCertDomain       = ""
	defaultCertCache        = "/tmp/cert_cache"
	defaultCleanupFrequency = 24
	defaultProxyImages      = "http-only"
)

// Config manages configuration parameters.
type Config struct {
	IsHTTPS  bool
	baseURL  string
	rootURL  string
	basePath string
}

func (c *Config) get(key, fallback string) string {
	value := os.Getenv(key)
	if value == "" {
		return fallback
	}

	return value
}

func (c *Config) getInt(key string, fallback int) int {
	value := os.Getenv(key)
	if value == "" {
		return fallback
	}

	v, _ := strconv.Atoi(value)
	return v
}

func (c *Config) parseBaseURL() {
	baseURL := os.Getenv("BASE_URL")
	if baseURL == "" {
		return
	}

	if baseURL[len(baseURL)-1:] == "/" {
		baseURL = baseURL[:len(baseURL)-1]
	}

	u, err := url.Parse(baseURL)
	if err != nil {
		logger.Error("Invalid BASE_URL: %v", err)
		return
	}

	scheme := strings.ToLower(u.Scheme)
	if scheme != "https" && scheme != "http" {
		logger.Error("Invalid BASE_URL: scheme must be http or https")
		return
	}

	c.baseURL = baseURL
	c.basePath = u.Path

	u.Path = ""
	c.rootURL = u.String()
}

// HasDebugMode returns true if debug mode is enabled.
func (c *Config) HasDebugMode() bool {
	return c.get("DEBUG", "") != ""
}

// BaseURL returns the application base URL with path.
func (c *Config) BaseURL() string {
	return c.baseURL
}

// RootURL returns the base URL without path.
func (c *Config) RootURL() string {
	return c.rootURL
}

// BasePath returns the application base path according to the base URL.
func (c *Config) BasePath() string {
	return c.basePath
}

// DatabaseURL returns the database URL.
func (c *Config) DatabaseURL() string {
	value, exists := os.LookupEnv("DATABASE_URL")
	if !exists {
		logger.Info("The environment variable DATABASE_URL is not configured (the default value is used instead)")
	}

	if value == "" {
		value = defaultDatabaseURL
	}

	return value
}

// DatabaseMaxConnections returns the number of maximum database connections.
func (c *Config) DatabaseMaxConnections() int {
	return c.getInt("DATABASE_MAX_CONNS", defaultDatabaseMaxConns)
}

// ListenAddr returns the listen address for the HTTP server.
func (c *Config) ListenAddr() string {
	if port := os.Getenv("PORT"); port != "" {
		return ":" + port
	}

	return c.get("LISTEN_ADDR", defaultListenAddr)
}

// CertFile returns the SSL certificate filename if any.
func (c *Config) CertFile() string {
	return c.get("CERT_FILE", defaultCertFile)
}

// KeyFile returns the private key filename for custom SSL certificate.
func (c *Config) KeyFile() string {
	return c.get("KEY_FILE", defaultKeyFile)
}

// CertDomain returns the domain to use for Let's Encrypt certificate.
func (c *Config) CertDomain() string {
	return c.get("CERT_DOMAIN", defaultCertDomain)
}

// CertCache returns the directory to use for Let's Encrypt session cache.
func (c *Config) CertCache() string {
	return c.get("CERT_CACHE", defaultCertCache)
}

// CleanupFrequency returns the interval for cleanup jobs.
func (c *Config) CleanupFrequency() int {
	return c.getInt("CLEANUP_FREQUENCY", defaultCleanupFrequency)
}

// WorkerPoolSize returns the number of background worker.
func (c *Config) WorkerPoolSize() int {
	return c.getInt("WORKER_POOL_SIZE", defaultWorkerPoolSize)
}

// PollingFrequency returns the interval to refresh feeds in the background.
func (c *Config) PollingFrequency() int {
	return c.getInt("POLLING_FREQUENCY", defaultPollingFrequency)
}

// BatchSize returns the number of feeds to send for background processing.
func (c *Config) BatchSize() int {
	return c.getInt("BATCH_SIZE", defaultBatchSize)
}

// IsOAuth2UserCreationAllowed returns true if user creation is allowed for OAuth2 users.
func (c *Config) IsOAuth2UserCreationAllowed() bool {
	return c.getInt("OAUTH2_USER_CREATION", 0) == 1
}

// OAuth2ClientID returns the OAuth2 Client ID.
func (c *Config) OAuth2ClientID() string {
	return c.get("OAUTH2_CLIENT_ID", "")
}

// OAuth2ClientSecret returns the OAuth2 client secret.
func (c *Config) OAuth2ClientSecret() string {
	return c.get("OAUTH2_CLIENT_SECRET", "")
}

// OAuth2RedirectURL returns the OAuth2 redirect URL.
func (c *Config) OAuth2RedirectURL() string {
	return c.get("OAUTH2_REDIRECT_URL", "")
}

// OAuth2Provider returns the name of the OAuth2 provider configured.
func (c *Config) OAuth2Provider() string {
	return c.get("OAUTH2_PROVIDER", "")
}

// HasHSTS returns true if HTTP Strict Transport Security is enabled.
func (c *Config) HasHSTS() bool {
	return c.get("DISABLE_HSTS", "") == ""
}

// RunMigrations returns true if the environment variable RUN_MIGRATIONS is not empty.
func (c *Config) RunMigrations() bool {
	return c.get("RUN_MIGRATIONS", "") != ""
}

// CreateAdmin returns true if the environment variable CREATE_ADMIN is not empty.
func (c *Config) CreateAdmin() bool {
	return c.get("CREATE_ADMIN", "") != ""
}

// PocketConsumerKey returns the Pocket Consumer Key if defined as environment variable.
func (c *Config) PocketConsumerKey(defaultValue string) string {
	return c.get("POCKET_CONSUMER_KEY", defaultValue)
}

// ProxyImages returns "none" to never proxy, "http-only" to proxy non-HTTPS, "all" to always proxy.
func (c *Config) ProxyImages() string {
	return c.get("PROXY_IMAGES", defaultProxyImages)
}

// NewConfig returns a new Config.
func NewConfig() *Config {
	cfg := &Config{
		baseURL: defaultBaseURL,
		rootURL: defaultBaseURL,
		IsHTTPS: os.Getenv("HTTPS") != "",
	}

	cfg.parseBaseURL()
	return cfg
}