package main

import (
	"encoding/base64"
	"encoding/json"
	"io"
	"log"
	"net/http"
	"strings"

	"github.com/alexflint/go-arg"
)

type NodeData struct {
	id    string
	title string
}

type Node struct {
	children []*Node
	data     NodeData
}

func (n Node) printChildren(level int) {
	log.Printf("%v%v", strings.Repeat("\t", level), n.data.title)
	// leaf note
	if len(n.children) == 0 {
		return
	}
	for _, child := range n.children {
		child.printChildren(level + 1)
	}
}

func (n *Node) getChildWithID(id string) (node *Node, hasChild bool) {
	for _, c := range n.children {
		if c.data.id == id {
			return c, true
		}
	}
	empty := Node{}
	return &empty, false
}

func (n *Node) addChild(child *Node) {
	n.children = append(n.children, child)
}

type spaceResult struct {
	Results []struct {
		ID        string `json:"id"`
		Type      string `json:"type"`
		Status    string `json:"status"`
		Title     string `json:"title"`
		Ancestors []struct {
			ID                  string `json:"id"`
			Type                string `json:"type"`
			Status              string `json:"status"`
			Title               string `json:"title"`
			MacroRenderedOutput struct {
			} `json:"macroRenderedOutput"`
			Extensions struct {
				Position int `json:"position"`
			} `json:"extensions"`
			Expandable struct {
				Container           string `json:"container"`
				Metadata            string `json:"metadata"`
				Restrictions        string `json:"restrictions"`
				History             string `json:"history"`
				Body                string `json:"body"`
				Version             string `json:"version"`
				Descendants         string `json:"descendants"`
				Space               string `json:"space"`
				ChildTypes          string `json:"childTypes"`
				Operations          string `json:"operations"`
				SchedulePublishDate string `json:"schedulePublishDate"`
				Children            string `json:"children"`
				Ancestors           string `json:"ancestors"`
			} `json:"_expandable"`
			Links struct {
				Self   string `json:"self"`
				Tinyui string `json:"tinyui"`
				Editui string `json:"editui"`
				Webui  string `json:"webui"`
			} `json:"_links"`
		} `json:"ancestors"`
		MacroRenderedOutput struct {
		} `json:"macroRenderedOutput"`
		Extensions struct {
			Position int `json:"position"`
		} `json:"extensions"`
		Expandable struct {
			ChildTypes          string `json:"childTypes"`
			Container           string `json:"container"`
			Metadata            string `json:"metadata"`
			Operations          string `json:"operations"`
			SchedulePublishDate string `json:"schedulePublishDate"`
			Children            string `json:"children"`
			Restrictions        string `json:"restrictions"`
			History             string `json:"history"`
			Body                string `json:"body"`
			Version             string `json:"version"`
			Descendants         string `json:"descendants"`
			Space               string `json:"space"`
		} `json:"_expandable"`
		Links struct {
			Self   string `json:"self"`
			Tinyui string `json:"tinyui"`
			Editui string `json:"editui"`
			Webui  string `json:"webui"`
		} `json:"_links"`
	} `json:"results"`
	Start int `json:"start"`
	Limit int `json:"limit"`
	Size  int `json:"size"`
	Links struct {
		Base    string `json:"base"`
		Context string `json:"context"`
		Next    string `json:"next"`
		Self    string `json:"self"`
	} `json:"_links"`
}

func getSpaceChildren(url, user, token string) spaceResult {
	b64Auth := base64.StdEncoding.EncodeToString([]byte(user + ":" + token))
	client := &http.Client{}
	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		log.Fatal(err)
	}
	req.Header.Add("Authorization", "Basic "+b64Auth)
	resp, err := client.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	if resp.StatusCode != http.StatusOK {
		log.Fatalf("Error fetching url: %v, status code: %v", url, resp.StatusCode)
	}
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		log.Fatal(err)
	}
	var result spaceResult
	json.Unmarshal(body, &result)
	return result
}

func createPageTree(s *spaceResult) {
	var parent *Node
	root := Node{data: NodeData{title: "root"}}
	for _, page := range s.Results {
		parent = &root
		// ignore the root node
		if len(page.Ancestors) == 0 {
			continue
		}
		// create branches from ancestors
		for i, ancestor := range page.Ancestors {
			// skip root node
			if i == 0 {
				continue
			}
			node, hasChild := parent.getChildWithID(ancestor.ID)
			if hasChild {
				parent = node
				continue
			}
			n := Node{data: NodeData{id: ancestor.ID, title: ancestor.Title}}
			parent.addChild(&n)
			parent = &n
		}
		// create leaf node
		n := Node{data: NodeData{id: page.ID, title: page.Title}}
		parent.addChild(&n)
	}
	root.printChildren(0)
}

func main() {
	var args struct {
		Baseurl  string `arg:"required" help:"Base URL of the Confluence instance (required)"`
		Spacekey string `arg:"required" help:"Spacekey to export (required)"`
		User     string `arg:"required" help:"User used for authentication (required)"`
		Token    string `arg:"required" help:"Token used for authentication (required)"`
	}
	arg.MustParse(&args)
	url := args.Baseurl + "/wiki/rest/api/space/" + args.Spacekey + "/content/page?expand=ancestors&limit=9999"
	result := getSpaceChildren(url, args.User, args.Token)
	createPageTree(&result)
}