package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"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    string            `json:"content"` // Reiner String, JSON kümmert sich um das Escaping des HTMLs
	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"`
}

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", "./stories", "Verzeichnis mit AsciiDoc/Markdown Dateien")
	frontendPtr := flag.String("frontend", "./frontend", "Pfad zum Verzeichnis der statischen Frontend-Dateien")
	outPtr := flag.String("out", "export/story.html", "Zielpfad für den Dateiexport (Single-File HTML)")
	servePtr := flag.Bool("serve", false, "Startet den API- & Preview-Server, statt zu exportieren")
	portPtr := flag.Int("port", 3344, "Port für den Server")
	flag.Parse()

	fmt.Println("\033[1;36m=== Computer Historyz :: CYOA Engine ===\033[0m")
	
	if info, err := os.Stat(*frontendPtr); os.IsNotExist(err) || !info.IsDir() {
		fmt.Printf("\033[1;33m[WARNUNG]\033[0m Frontend-Verzeichnis '%s' nicht gefunden!\n", *frontendPtr)
	}

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

	// --- EXPORT MODUS ---
	fmt.Printf("\033[1;34m[EXPORT]\033[0m Kompiliere Story-Graph via Asciidoctor aus '%s'...\n", *dirPtr)
	graph := loadStoryGraphFromDir(*dirPtr)
	validateGraph(graph)

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

	err := buildSingleFileExport(graph, *frontendPtr, *outPtr)
	if err != nil {
		fmt.Printf("\033[1;31m[FEHLER]\033[0m Build fehlgeschlagen: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("\033[1;32m[ERFOLG]\033[0m Single-File Story exportiert -> \033[1;33m%s\033[0m\n", *outPtr)
}

func startServer(port int, watchDir string, frontendDir string) {
	addr := fmt.Sprintf(":%d", port)

	http.HandleFunc("/api/graph", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Content-Type", "application/json")

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

			json.NewEncoder(w).Encode(graph)
			fmt.Println("\033[1;34m[POST-API]\033[0m Story-Graph verarbeitet.")
			return
		}

		if r.Method == http.MethodGet {
			graph := loadStoryGraphFromDir(watchDir)
			validateGraph(graph)
			json.NewEncoder(w).Encode(graph)
		}
	})

	fs := http.FileServer(http.Dir(frontendDir))
	http.Handle("/", fs)

	fmt.Printf("\n\033[1;32m[SERVER LÄUFT]\033[0m http://localhost:%d\n", port)
	if err := http.ListenAndServe(addr, nil); err != nil {
		fmt.Printf("\033[1;31m[FEHLER]\033[0m %v\n", err)
	}
}

func buildSingleFileExport(graph *StoryGraph, frontendDir string, outPath string) error {
	indexPath := filepath.Join(frontendDir, "index.html")
	htmlBytes, err := os.ReadFile(indexPath)
	if err != nil {
		return fmt.Errorf("konnte %s nicht lesen: %v", indexPath, err)
	}
	htmlStr := string(htmlBytes)

	cssBytes, _ := os.ReadFile(filepath.Join(frontendDir, "style.css"))
	logicBytes, _ := os.ReadFile(filepath.Join(frontendDir, "engine_logic.js"))
	uiBytes, _ := os.ReadFile(filepath.Join(frontendDir, "engine_ui.js"))

	graphJson, _ := json.Marshal(graph)

	// CSS ersetzen
	htmlStr = strings.Replace(htmlStr, `<link rel="stylesheet" href="style.css">`, fmt.Sprintf("<style>\n%s\n</style>", string(cssBytes)), 1)

	// JS ersetzen
	htmlStr = strings.Replace(htmlStr, `<script src="engine_logic.js"></script>`, fmt.Sprintf("<script>\n%s\n</script>", string(logicBytes)), 1)
	htmlStr = strings.Replace(htmlStr, `<script src="engine_ui.js"></script>`, fmt.Sprintf("<script>\n%s\n</script>", string(uiBytes)), 1)

	// JSON State in den Data-Block pressen
	re := regexp.MustCompile(`(?s)<script id="story-data" type="application/json">.*?</script>`)
	htmlStr = re.ReplaceAllString(htmlStr, fmt.Sprintf("<script id=\"story-data\" type=\"application/json\">\n%s\n</script>", string(graphJson)))

	return os.WriteFile(outPath, []byte(htmlStr), 0644)
}

// renderAsciidoctor piped rohen AsciiDoc Text in den lokalen Container-Prozess
func renderAsciidoctor(text string) string {
	if strings.TrimSpace(text) == "" {
		return ""
	}
	
	cmd := exec.Command("asciidoctor", "--embedded", "-")
	cmd.Stdin = strings.NewReader(text)
	
	out, err := cmd.Output()
	if err != nil {
		fmt.Printf("\033[1;33m[WARNUNG]\033[0m Asciidoctor Rendering fehlgeschlagen: %v\n", err)
		return strings.ReplaceAll(text, "\n", "<br>")
	}
	
	return 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 {
			relPath, _ := filepath.Rel(rootDir, path)
			parseContent(string(contentBytes), relPath, 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) }
	}
}