package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"html/template"
	"io"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strings"
)

type Choice struct {
	TargetID string `json:"targetId"`
	Text     string `json:"text"`
}

type StoryNode struct {
	ID         string            `json:"id"`
	Title      string            `json:"title"`
	Content    template.HTML     `json:"content"`
	Choices    []Choice          `json:"choices"`
	IsReboot   bool              `json:"isReboot"`
	IsEnd      bool              `json:"isEnd"`
	FileSource string            `json:"fileSource"`
	Metadata   map[string]string `json:"metadata"`
}

type StoryGraph struct {
	Nodes        map[string]*StoryNode `json:"nodes"`
	StartNodeID  string                `json:"startNodeId"`
	BrokenLinks  []string              `json:"brokenLinks"`
	OrphanNodes  []string              `json:"orphanNodes"`
	DeadEndNodes []string              `json:"deadEndNodes"`
}

// Struct für das saubere Injezieren der Frontend-Komponenten
type TemplateContext struct {
	Graph template.JS
	CSS   template.CSS
	Logic template.JS
	UI    template.JS
}

var (
	adocNodeRegex   = regexp.MustCompile(`\[\[([a-zA-Z0-9_\-]+)\]\]`)
	adocChoiceRegex = regexp.MustCompile(`<<([a-zA-Z0-9_\-]+)\s*,\s*([^>]+)>>`)
	mdChoiceRegex   = regexp.MustCompile(`\[([^\]]+)\]\((?:#)?([a-zA-Z0-9_\-]+)\)`)
	headingRegex    = regexp.MustCompile(`^(?:={1,4}|#{1,4})\s+(.+)`)
	metaRegex       = regexp.MustCompile(`(?i)\[meta:\s*([a-zA-Z0-9_]+)\s*=\s*([^\]]+)\]`)
)

func main() {
	dirPtr := flag.String("dir", ".", "Verzeichnis mit AsciiDoc/Markdown Dateien")
	outPtr := flag.String("out", "export/story.html", "Zielpfad für den Dateiexport")
	tmplPtr := flag.String("tmpl", "template.html", "Pfad zur HTML Template-Datei")
	servePtr := flag.Bool("serve", false, "Startet den API- & Preview-Server")
	portPtr := flag.Int("port", 8080, "Port für den Server")
	flag.Parse()

	fmt.Println("\033[1;36m=== Computer Historyz :: CYOA Engine (Modular) ===\033[0m")

	if *servePtr {
		startServer(*portPtr, *dirPtr, *outPtr, *tmplPtr)
		return
	}

	graph := loadStoryGraphFromDir(*dirPtr)
	validateGraph(graph)

	outDir := filepath.Dir(*outPtr)
	os.MkdirAll(outDir, 0755)

	if err := generateHTMLFile(graph, *outPtr, *tmplPtr); err != nil {
		fmt.Printf("\033[1;31m[FEHLER]\033[0m %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("\033[1;32m[ERFOLG]\033[0m Story modular generiert -> \033[1;33m%s\033[0m\n", *outPtr)
}

func readAsset(basePath, filename string) string {
	b, err := os.ReadFile(filepath.Join(filepath.Dir(basePath), filename))
	if err != nil {
		return fmt.Sprintf("/* %s nicht gefunden */", filename)
	}
	return string(b)
}

func renderAsciidoctor(text string) template.HTML {
	if strings.TrimSpace(text) == "" { return "" }
	cmd := exec.Command("asciidoctor", "--embedded", "-")
	cmd.Stdin = strings.NewReader(text)
	out, err := cmd.Output()
	if err != nil {
		fallback := strings.ReplaceAll(text, "\n", "<br>")
		return template.HTML(fallback)
	}
	return template.HTML(string(out))
}

func cleanBodyText(raw string) string {
	cleaned := adocChoiceRegex.ReplaceAllString(raw, "")
	cleaned = mdChoiceRegex.ReplaceAllString(cleaned, "")
	return strings.TrimSpace(cleaned)
}

func parseContent(rawContent string, sourceName string, graph *StoryGraph) {
	lines := strings.Split(rawContent, "\n")
	var currentNode *StoryNode = nil
	var currentBody strings.Builder

	for _, line := range lines {
		if matches := adocNodeRegex.FindStringSubmatch(line); len(matches) > 1 {
			if currentNode != nil {
				currentNode.Content = renderAsciidoctor(cleanBodyText(currentBody.String()))
				graph.Nodes[currentNode.ID] = currentNode
				currentBody.Reset()
			}
			nodeID := matches[1]
			currentNode = &StoryNode{ ID: nodeID, Title: nodeID, Choices: make([]Choice, 0), FileSource: sourceName, Metadata: make(map[string]string) }
			if graph.StartNodeID == "" || nodeID == "start" || nodeID == "node_start" { graph.StartNodeID = nodeID }
			continue
		}
		if currentNode == nil {
			if strings.TrimSpace(line) != "" {
				baseID := "start"
				if sourceName != "API_POST_Stream" { baseID = strings.TrimSuffix(filepath.Base(sourceName), filepath.Ext(sourceName)) }
				currentNode = &StoryNode{ ID: baseID, Title: baseID, Choices: make([]Choice, 0), FileSource: sourceName, Metadata: make(map[string]string) }
				if graph.StartNodeID == "" { graph.StartNodeID = baseID }
			} else { continue }
		}

		if mMatches := metaRegex.FindStringSubmatch(line); len(mMatches) > 2 {
			currentNode.Metadata[strings.ToLower(mMatches[1])] = strings.TrimSpace(mMatches[2]); continue
		}
		if hMatches := headingRegex.FindStringSubmatch(line); len(hMatches) > 1 && currentNode.Title == currentNode.ID {
			currentNode.Title = strings.TrimSpace(hMatches[1])
		}
		if cMatches := adocChoiceRegex.FindAllStringSubmatch(line, -1); len(cMatches) > 0 {
			for _, match := range cMatches { currentNode.Choices = append(currentNode.Choices, Choice{TargetID: match[1], Text: strings.TrimSpace(match[2])}) }
		}
		if mMatches := mdChoiceRegex.FindAllStringSubmatch(line, -1); len(mMatches) > 0 {
			for _, match := range mMatches { currentNode.Choices = append(currentNode.Choices, Choice{TargetID: match[2], Text: strings.TrimSpace(match[1])}) }
		}

		lowerLine := strings.ToLower(line)
		if strings.Contains(lowerLine, "[reboot]") || strings.Contains(lowerLine, "speicherabbild") { currentNode.IsReboot = true }
		if strings.Contains(lowerLine, "[ende]") || strings.Contains(lowerLine, "[end]") { currentNode.IsEnd = true }

		currentBody.WriteString(line + "\n")
	}
	if currentNode != nil {
		currentNode.Content = renderAsciidoctor(cleanBodyText(currentBody.String()))
		graph.Nodes[currentNode.ID] = currentNode
	}
}

func loadStoryGraphFromDir(rootDir string) *StoryGraph {
	graph := &StoryGraph{Nodes: make(map[string]*StoryNode)}
	filepath.Walk(rootDir, func(path string, info os.FileInfo, err error) error {
		if err != nil || info.IsDir() { return nil }
		ext := strings.ToLower(filepath.Ext(path))
		if ext != ".adoc" && ext != ".md" { return nil }
		contentBytes, err := os.ReadFile(path)
		if err == nil { parseContent(string(contentBytes), filepath.Base(path), graph) }
		return nil
	})
	return graph
}

func validateGraph(g *StoryGraph) {
	referenced := make(map[string]bool)
	if g.StartNodeID != "" { referenced[g.StartNodeID] = true }
	for id, node := range g.Nodes {
		for _, choice := range node.Choices {
			referenced[choice.TargetID] = true
			if _, exists := g.Nodes[choice.TargetID]; !exists { g.BrokenLinks = append(g.BrokenLinks, fmt.Sprintf("%s -> %s (in %s)", id, choice.TargetID, node.FileSource)) }
		}
		if len(node.Choices) == 0 && !node.IsReboot && !node.IsEnd { g.DeadEndNodes = append(g.DeadEndNodes, id) }
	}
	for id := range g.Nodes { if !referenced[id] { g.OrphanNodes = append(g.OrphanNodes, id) } }
}

func getContext(graph *StoryGraph, tmplPath string) TemplateContext {
	graphJson, _ := json.Marshal(graph)
	return TemplateContext{
		Graph: template.JS(graphJson),
		CSS:   template.CSS(readAsset(tmplPath, "style.css")),
		Logic: template.JS(readAsset(tmplPath, "engine_logic.js")),
		UI:    template.JS(readAsset(tmplPath, "engine_ui.js")),
	}
}

func generateHTMLFile(g *StoryGraph, outPath string, tmplPath string) error {
	tmpl, err := template.ParseFiles(tmplPath)
	if err != nil { return fmt.Errorf("Template-Fehler: %v", err) }
	f, err := os.Create(outPath)
	if err != nil { return err }
	defer f.Close()
	return tmpl.Execute(f, getContext(g, tmplPath))
}

func startServer(port int, watchDir string, htmlPath string, tmplPath string) {
	addr := fmt.Sprintf(":%d", port)
	fmt.Printf("\n\033[1;32m[CONTAINER-API LÄUFT]\033[0m Port: %d | Nutzt Template: %s\n", port, tmplPath)

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")

		if r.Method == http.MethodPost {
			bodyBytes, err := io.ReadAll(r.Body)
			if err != nil { http.Error(w, "Daten defekt", http.StatusBadRequest); return }
			
			graph := &StoryGraph{Nodes: make(map[string]*StoryNode)}
			parseContent(string(bodyBytes), "API_POST_Stream", graph)
			validateGraph(graph)

			w.Header().Set("Content-Type", "text/html; charset=utf-8")
			tmpl, err := template.ParseFiles(tmplPath)
			if err != nil { http.Error(w, "Template-Fehler: "+err.Error(), http.StatusInternalServerError); return }
			
			tmpl.Execute(w, getContext(graph, tmplPath))
			fmt.Println("\033[1;34m[POST-API]\033[0m Modularer Stack gerendert.")
			return
		}
		if r.Method == http.MethodGet {
			freshGraph := loadStoryGraphFromDir(watchDir)
			_ = generateHTMLFile(freshGraph, htmlPath, tmplPath)
			http.ServeFile(w, r, htmlPath)
		}
	})
	http.ListenAndServe(addr, nil)
}