/* Copyright Azareal 2016 - 2017 */
package main

//import "fmt"
import "log"
import "io"
import "os"
import "strings"
import "mime"
import "io/ioutil"
import "path/filepath"
import "encoding/json"
import "net/http"

var defaultTheme string
var themes map[string]Theme = make(map[string]Theme)
//var overriden_templates map[string]interface{} = make(map[string]interface{})
var overriden_templates map[string]bool = make(map[string]bool)

type Theme struct
{
	Name string
	FriendlyName string
	Version string
	Creator string
	FullImage string
	MobileFriendly bool
	Settings map[string]ThemeSetting
	Templates []TemplateMapping
	
	// This variable should only be set and unset by the system, not the theme meta file
	Active bool
}

type ThemeSetting struct
{
	FriendlyName string
	Options []string
}

type TemplateMapping struct
{
	Name string
	Source string
	//When string
}

func init_themes() {
	themeFiles, err := ioutil.ReadDir("./themes")
	if err != nil {
		log.Fatal(err)
	}
	
	for _, themeFile := range themeFiles {
		if !themeFile.IsDir() {
			continue
		}
		
		themeName := themeFile.Name()
		log.Print("Adding theme '" + themeName + "'")
		themeFile, err := ioutil.ReadFile("./themes/" + themeName + "/theme.json")
		if err != nil {
			log.Fatal(err)
		}
		
		var theme Theme
		err = json.Unmarshal(themeFile, &theme)
		if err != nil {
			log.Fatal(err)
		}
		
		
		theme.Active = false // Set this to false, just in case someone explicitly overrode this value in the JSON file
		
		if theme.FullImage != "" {
			log.Print("Adding theme image")
			err = add_static_file("./themes/" + themeName + "/" + theme.FullImage, "./themes/" + themeName)
			if err != nil {
				log.Fatal(err)
			}
		}
		
		themes[theme.Name] = theme
	}
}

func add_theme_static_files(themeName string) {
	err := filepath.Walk("./themes/" + themeName + "/public", func(path string, f os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if f.IsDir() {
			return nil
		}
		path = strings.Replace(path,"\\","/",-1)
		
		log.Print("Attempting to add static file '" + path + "' for default theme '" + themeName + "'")
		data, err := ioutil.ReadFile(path)
		if err != nil {
			return err
		}
		
		path = strings.TrimPrefix(path,"themes/" + themeName + "/public")
		log.Print("Added the '" + path + "' static file for default theme " + themeName + ".")
		
		static_files["/static" + path] = SFile{data,0,int64(len(data)),mime.TypeByExtension(filepath.Ext("/themes/" + themeName + "/public" + path)),f,f.ModTime().UTC().Format(http.TimeFormat)}
		return nil
	})
	if err != nil {
		panic(err)
	}
}

func map_theme_templates(theme Theme) {
	if theme.Templates != nil {
		for _, themeTmpl := range theme.Templates {
			if themeTmpl.Name == "" {
				log.Fatal("Invalid destination template name")
			}
			if themeTmpl.Source == "" {
				log.Fatal("Invalid source template name")
			}
			
			// `go generate` is one possibility for letting plugins inject custom page structs, but it would simply add another step of compilation. It might be simpler than the current build process from the perspective of the administrator?
			
			dest_tmpl_ptr, ok := tmpl_ptr_map[themeTmpl.Name]
			if !ok {
				log.Fatal("The destination template doesn't exist!")
			}
			source_tmpl_ptr, ok := tmpl_ptr_map[themeTmpl.Source]
			if !ok {
				log.Fatal("The source template doesn't exist!")
			}
			
			switch d_tmpl_ptr := dest_tmpl_ptr.(type) {
				case *func(TopicPage,io.Writer):
					switch s_tmpl_ptr := source_tmpl_ptr.(type) {
						case *func(TopicPage,io.Writer):
							//overriden_templates[themeTmpl.Name] = d_tmpl_ptr
							overriden_templates[themeTmpl.Name] = true
							//log.Print("Topic Handle")
							//fmt.Println(template_topic_handle)
							//log.Print("Before")
							//fmt.Println(d_tmpl_ptr)
							//fmt.Println(*d_tmpl_ptr)
							//log.Print("Source")
							//fmt.Println(s_tmpl_ptr)
							//fmt.Println(*s_tmpl_ptr)
							*d_tmpl_ptr = *s_tmpl_ptr
							//log.Print("After")
							//fmt.Println(d_tmpl_ptr)
							//fmt.Println(*d_tmpl_ptr)
							//log.Print("Source")
							//fmt.Println(s_tmpl_ptr)
							//fmt.Println(*s_tmpl_ptr)
						default:
							log.Fatal("The source and destination templates are incompatible")
					}
				case *func(TopicsPage,io.Writer):
					switch s_tmpl_ptr := source_tmpl_ptr.(type) {
						case *func(TopicsPage,io.Writer):
							//overriden_templates[themeTmpl.Name] = d_tmpl_ptr
							overriden_templates[themeTmpl.Name] = true
							*d_tmpl_ptr = *s_tmpl_ptr
						default:
							log.Fatal("The source and destination templates are incompatible")
					}
				case *func(ForumPage,io.Writer):
					switch s_tmpl_ptr := source_tmpl_ptr.(type) {
						case *func(ForumPage,io.Writer):
							//overriden_templates[themeTmpl.Name] = d_tmpl_ptr
							overriden_templates[themeTmpl.Name] = true
							*d_tmpl_ptr = *s_tmpl_ptr
						default:
							log.Fatal("The source and destination templates are incompatible")
					}
				case *func(ForumsPage,io.Writer):
					switch s_tmpl_ptr := source_tmpl_ptr.(type) {
						case *func(ForumsPage,io.Writer):
							//overriden_templates[themeTmpl.Name] = d_tmpl_ptr
							overriden_templates[themeTmpl.Name] = true
							*d_tmpl_ptr = *s_tmpl_ptr
						default:
							log.Fatal("The source and destination templates are incompatible")
					}
				case *func(ProfilePage,io.Writer):
					switch s_tmpl_ptr := source_tmpl_ptr.(type) {
						case *func(ProfilePage,io.Writer):
							//overriden_templates[themeTmpl.Name] = d_tmpl_ptr
							overriden_templates[themeTmpl.Name] = true
							*d_tmpl_ptr = *s_tmpl_ptr
						default:
							log.Fatal("The source and destination templates are incompatible")
					}
				case *func(Page,io.Writer):
					switch s_tmpl_ptr := source_tmpl_ptr.(type) {
						case *func(Page,io.Writer):
							//overriden_templates[themeTmpl.Name] = d_tmpl_ptr
							overriden_templates[themeTmpl.Name] = true
							*d_tmpl_ptr = *s_tmpl_ptr
						default:
							log.Fatal("The source and destination templates are incompatible")
					}
				default:
					log.Fatal("Unknown destination template type!")
			}
		}
	}
}

func reset_template_overrides() {
	log.Print("Resetting the template overrides")
	
	for name, _ := range overriden_templates {
		log.Print("Resetting '" + name + "' template override")
		
		origin_pointer, ok := tmpl_ptr_map["o_" + name]
		if !ok {
			//log.Fatal("The origin template doesn't exist!")
			log.Print("The origin template doesn't exist!")
			return
		}
		
		dest_tmpl_ptr, ok := tmpl_ptr_map[name]
		if !ok {
			//log.Fatal("The destination template doesn't exist!")
			log.Print("The destination template doesn't exist!")
			return
		}
		
		// Not really a pointer, more of a function handle, an artifact from one of the earlier versions of themes.go
		switch o_ptr := origin_pointer.(type) {
			case func(TopicPage,io.Writer):
				switch d_ptr := dest_tmpl_ptr.(type) {
					case *func(TopicPage,io.Writer):
						//log.Print("Topic Handle")
						//fmt.Println(template_topic_handle)
						//log.Print("Before")
						//fmt.Println(d_ptr)
						//fmt.Println(*d_ptr)
						//log.Print("Origin")
						//fmt.Println(o_ptr)
						*d_ptr = o_ptr
						//log.Print("After")
						//fmt.Println(d_ptr)
						//fmt.Println(*d_ptr)
						//log.Print("Origin")
						//fmt.Println(o_ptr)
					default:
						log.Fatal("The origin and destination templates are incompatible")
				}
			case func(TopicsPage,io.Writer):
				switch d_ptr := dest_tmpl_ptr.(type) {
					case *func(TopicsPage,io.Writer):
						*d_ptr = o_ptr
					default:
						log.Fatal("The origin and destination templates are incompatible")
				}
			case func(ForumPage,io.Writer):
				switch d_ptr := dest_tmpl_ptr.(type) {
					case *func(ForumPage,io.Writer):
						*d_ptr = o_ptr
					default:
						log.Fatal("The origin and destination templates are incompatible")
				}
			case func(ForumsPage,io.Writer):
				switch d_ptr := dest_tmpl_ptr.(type) {
					case *func(ForumsPage,io.Writer):
						*d_ptr = o_ptr
					default:
						log.Fatal("The origin and destination templates are incompatible")
				}
			case func(ProfilePage,io.Writer):
				switch d_ptr := dest_tmpl_ptr.(type) {
					case *func(ProfilePage,io.Writer):
						*d_ptr = o_ptr
					default:
						log.Fatal("The origin and destination templates are incompatible")
				}
			default:
				log.Fatal("Unknown destination template type!")
		}
		log.Print("The template override was reset")
	}
	overriden_templates = make(map[string]bool)
	log.Print("All of the template overrides have been reset")
}