package config

import (
	_ "embed"
	"fmt"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"strings"

	"github.com/photoprism/photoprism/pkg/clean"
	"github.com/photoprism/photoprism/pkg/fs"
)

//go:embed robots.txt
var robotsTxt []byte

const localhost = "localhost"

// BaseUri returns the site base URI for a given resource.
func (c *Config) BaseUri(res string) string {
	if c.SiteUrl() == "" {
		return res
	}

	u, err := url.Parse(c.SiteUrl())

	if err != nil {
		return res
	}

	return strings.TrimRight(u.EscapedPath(), "/") + res
}

// ApiUri returns the api URI.
func (c *Config) ApiUri() string {
	return c.BaseUri(ApiUri)
}

// LibraryUri returns the user interface URI for the given resource.
func (c *Config) LibraryUri(res string) string {
	return c.BaseUri(LibraryUri + res)
}

// ContentUri returns the content delivery URI based on the CdnUrl and the ApiUri.
func (c *Config) ContentUri() string {
	return c.CdnUrl(c.ApiUri())
}

// DownloadUrl returns the download URL based on the SiteUrl and the DownloadUri.
func (c *Config) DownloadUrl() string {
	return strings.TrimRight(c.options.SiteUrl, "/") + DownloadUri
}

// VideoUri returns the video streaming URI.
func (c *Config) VideoUri() string {
	if c.CdnVideo() {
		return c.ContentUri()
	}

	return c.ApiUri()
}

// StaticUri returns the static content URI.
func (c *Config) StaticUri() string {
	return c.CdnUrl(c.BaseUri(StaticUri))
}

// StaticAssetUri returns the resource URI of the static file asset.
func (c *Config) StaticAssetUri(res string) string {
	return c.StaticUri() + "/" + res
}

// SiteUrl returns the public server URL (default is "http://localhost:2342/").
func (c *Config) SiteUrl() string {
	if c.options.SiteUrl == "" {
		return "http://localhost:2342/"
	}

	return strings.TrimRight(c.options.SiteUrl, "/") + "/"
}

// SiteHttps checks if the site URL uses HTTPS.
func (c *Config) SiteHttps() bool {
	if c.options.SiteUrl == "" {
		return false
	}

	return strings.HasPrefix(c.options.SiteUrl, "https://")
}

// SiteDomain returns the public hostname without protocol or post.
func (c *Config) SiteDomain() string {
	if u, err := url.Parse(c.SiteUrl()); err != nil {
		return localhost
	} else {
		return u.Hostname()
	}
}

// SiteHost returns the public hostname and port number in the format "domain:port".
func (c *Config) SiteHost() string {
	if u, err := url.Parse(c.SiteUrl()); err != nil {
		return localhost
	} else if hostname := u.Hostname(); hostname == "" {
		return localhost
	} else if port := u.Port(); port != "" {
		return fmt.Sprintf("%s:%s", hostname, port)
	} else {
		return hostname
	}
}

// SiteAuthor returns the site author / copyright.
func (c *Config) SiteAuthor() string {
	return c.options.SiteAuthor
}

// SiteTitle returns the main site title (default is application name).
func (c *Config) SiteTitle() string {
	if c.options.SiteTitle == "" {
		return c.Name()
	}

	return c.options.SiteTitle
}

// SiteCaption returns a short site caption.
func (c *Config) SiteCaption() string {
	return c.options.SiteCaption
}

// SiteDescription returns a long site description.
func (c *Config) SiteDescription() string {
	return c.options.SiteDescription
}

// SiteFavicon returns the site favicon image name.
func (c *Config) SiteFavicon() string {
	if c.options.SiteFavicon != "" {
		if fs.FileExistsNotEmpty(c.options.SiteFavicon) {
			return c.options.SiteFavicon
		} else if fileName := filepath.Join(c.ThemePath(), strings.TrimPrefix(c.options.SiteFavicon, ThemeUri)); fs.FileExistsNotEmpty(fileName) {
			return fileName
		} else if fileName = c.StaticImgFile(c.options.SiteFavicon); fs.FileExistsNotEmpty(fileName) {
			return fileName
		}
	}

	return c.StaticImgFile("favicon.ico")
}

// SitePreview returns the site preview image URL for sharing.
func (c *Config) SitePreview() string {
	if c.options.SitePreview != "" {
		if strings.HasPrefix(c.options.SitePreview, "http") {
			return c.options.SitePreview

		} else if fileName := filepath.Join(c.ThemePath(), c.options.SitePreview); fs.FileExistsNotEmpty(fileName) {
			return strings.TrimRight(c.options.SiteUrl, "/") + path.Join(ThemeUri, c.options.SitePreview)
		}

		return c.SiteUrl() + strings.TrimPrefix(c.options.SitePreview, "/")
	}

	return fmt.Sprintf("https://i.photoprism.app/prism?cover=64&style=centered%%20dark&caption=none&title=%s", url.QueryEscape(c.AppName()))
}

// LegalInfo returns the legal info text for the page footer.
func (c *Config) LegalInfo() string {
	if s := c.CliContextString("imprint"); s != "" {
		log.Warnf("config: option 'imprint' is deprecated, please use 'legal-info'")
		return s
	}

	return c.options.LegalInfo
}

// LegalUrl returns the legal info url.
func (c *Config) LegalUrl() string {
	if s := c.CliContextString("imprint-url"); s != "" {
		log.Warnf("config: option 'imprint-url' is deprecated, please use 'legal-url'")
		return s
	}

	return c.options.LegalUrl
}

// RobotsTxt returns the content of the robots.txt file to be used for this site:
// https://developers.google.com/search/docs/crawling-indexing/robots/create-robots-txt
func (c *Config) RobotsTxt() ([]byte, error) {
	if c.Demo() && c.Public() {
		// Allow public demo instances to be indexed.
		return []byte(fmt.Sprintf("User-agent: *\nDisallow: /\nAllow: %s/\nAllow: %s/\nAllow: .js\nAllow: .css", LibraryUri, StaticUri)), nil
	} else if c.Public() {
		// Do not allow other instances to be indexed when public mode is enabled.
		return robotsTxt, nil
	} else if fileName := filepath.Join(c.ConfigPath(), "robots.txt"); !fs.FileExists(fileName) {
		// Do not allow indexing if config/robots.txt does not exist.
		return robotsTxt, nil
	} else if robots, robotsErr := os.ReadFile(fileName); robotsErr != nil { //nolint:gosec // robots file path derived from config directory
		// Log error and do not allow indexing if config/robots.txt cannot be read.
		log.Debugf("config: failed to read robots.txt file (%s)", clean.Error(robotsErr))
		return robotsTxt, robotsErr
	} else {
		// Return content of the config/robots.txt file.
		return robots, nil
	}
}