// Command fakediscourse is the smoke-test Discourse: a tiny in-memory
// instance enforcing Api-Key auth, serving exactly what the client covers
// (current user, categories, topics, posts). It exists so the smoke test
// can drive the REAL CLI binary end to end without ever touching a live
// forum. Not built into the library, never shipped.
package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"strconv"
	"strings"
	"sync"
)

const smokeKey = "smoke-key-do-not-use"

type server struct {
	mu       sync.Mutex
	cats     []map[string]any
	posts    map[int]map[string]any
	topics   []map[string]any
	nextCat  int
	nextPost int
	nextT    int
	pms      []map[string]any // recorded private messages, creation order
}

func main() {
	addr := ":8610"
	if len(os.Args) == 3 && os.Args[1] == "-addr" {
		addr = os.Args[2]
	}
	s := &server{
		cats: []map[string]any{
			{"id": 1, "name": "General", "slug": "general", "color": "0088CC", "text_color": "FFFFFF", "topic_count": 0},
			{"id": 2, "name": "MOPAC Briefings", "slug": "mopac-briefings", "color": "3AB54A", "text_color": "FFFFFF", "topic_count": 0},
		},
		posts:    map[int]map[string]any{},
		nextCat:  3,
		nextPost: 100,
		nextT:    10,
	}

	mux := http.NewServeMux()
	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		if r.Header.Get("Api-Key") != smokeKey || r.Header.Get("Api-Username") != "smoker" {
			reply(w, 403, map[string]any{"errors": []string{"Bad or missing API key"}})
			return
		}
		s.mu.Lock()
		defer s.mu.Unlock()
		path := r.URL.Path
		switch {
		case path == "/session/current.json" && r.Method == "GET":
			reply(w, 200, map[string]any{"current_user": map[string]any{"id": 7, "username": "smoker", "admin": true}})

		case path == "/categories.json" && r.Method == "GET":
			reply(w, 200, map[string]any{"category_list": map[string]any{"categories": s.cats}})

		case path == "/categories.json" && r.Method == "POST":
			var req map[string]any
			if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
				reply(w, 400, map[string]any{"errors": []string{"bad json"}})
				return
			}
			name, _ := req["name"].(string)
			cat := map[string]any{
				"id": s.nextCat, "name": name,
				"slug":  strings.ToLower(strings.ReplaceAll(name, " ", "-")),
				"color": orDefault(req["color"], "3AB54A"), "text_color": orDefault(req["text_color"], "FFFFFF"),
				"topic_count": 0,
			}
			s.nextCat++
			s.cats = append(s.cats, cat)
			reply(w, 200, cat)

		case path == "/posts.json" && r.Method == "POST":
			var req map[string]any
			if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
				reply(w, 400, nil)
				return
			}
			topicID, _ := req["topic_id"].(float64)
			pid := s.nextPost
			s.nextPost++
			if topicID == 0 {
				title, _ := req["title"].(string)
				if tu, _ := req["target_usernames"].(string); tu != "" || hasAnyKey(req, "target_group_names", "target_emails") {
					// private-message creation
					if strings.Contains(str(req["target_usernames"]), "denied") {
						reply(w, 403, map[string]any{"errors": []string{"You are not permitted to view the requested resource."}})
						return
					}
					tid := s.nextT
					s.nextT++
					slug := strings.ToLower(strings.ReplaceAll(title, " ", "-"))
					s.pms = append(s.pms, map[string]any{
						"topic_id": tid, "title": title,
						"target_usernames": req["target_usernames"], "raw": req["raw"],
					})
					s.posts[pid] = map[string]any{"id": pid, "topic_id": tid, "raw": req["raw"], "post_number": 1}
					reply(w, 200, map[string]any{"id": pid, "topic_id": tid, "topic_slug": slug})
					return
				}
				catID, _ := req["category"].(float64)
				tid := s.nextT
				s.nextT++
				slug := strings.ToLower(strings.ReplaceAll(title, " ", "-"))
				s.topics = append(s.topics, map[string]any{"id": tid, "title": title, "slug": slug, "category_id": int(catID)})
				s.posts[pid] = map[string]any{"id": pid, "topic_id": tid, "raw": req["raw"], "post_number": 1}
				reply(w, 200, map[string]any{"id": pid, "topic_id": tid, "topic_slug": slug})
				return
			}
			s.posts[pid] = map[string]any{"id": pid, "topic_id": int(topicID), "raw": req["raw"], "post_number": 2}
			reply(w, 200, map[string]any{"id": pid, "topic_id": int(topicID), "topic_slug": "existing"})

		case strings.HasPrefix(path, "/posts/") && r.Method == "PUT":
			id, _ := strconv.Atoi(strings.SplitN(strings.TrimPrefix(path, "/posts/"), ".", 2)[0])
			var body struct {
				Post struct {
					Raw        string `json:"raw"`
					EditReason string `json:"edit_reason"`
				} `json:"post"`
			}
			if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
				reply(w, 400, nil)
				return
			}
			p, ok := s.posts[id]
			if !ok {
				reply(w, 404, nil)
				return
			}
			p["raw"] = body.Post.Raw
			s.posts[id] = p
			reply(w, 200, map[string]any{"post": p})

		case strings.HasPrefix(path, "/c/") && r.Method == "GET":
			reply(w, 200, map[string]any{"topic_list": map[string]any{"topics": s.topics}})

		case path == "/latest.json" && r.Method == "GET":
			reply(w, 200, map[string]any{"topic_list": map[string]any{"topics": s.topics}})

		case path == "/search.json" && r.Method == "GET":
			term := strings.ToLower(r.URL.Query().Get("term"))
			var topics, posts []map[string]any
			for _, t := range s.topics {
				if term != "" && strings.Contains(strings.ToLower(str(t["title"])), term) {
					topics = append(topics, t)
					posts = append(posts, map[string]any{
						"id": 900 + t["id"].(int), "topic_id": t["id"], "username": "smoker",
						"blurb":                "match on " + str(t["title"]),
						"topic_title_headline": t["title"],
					})
				}
			}
			reply(w, 200, map[string]any{"posts": posts, "topics": topics, "users": []any{}, "categories": []any{}})

		case path == "/__pms.json" && r.Method == "GET":
			reply(w, 200, map[string]any{"private_messages": s.pms})

		default:
			reply(w, 404, map[string]any{"errors": []string{"not found on the smoke instance"}})
		}
	})
	fmt.Printf("fakediscourse listening on %s (api-key enforced)\n", addr)
	log.Fatal(http.ListenAndServe(addr, mux))
}

func reply(w http.ResponseWriter, code int, body any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(code)
	_ = json.NewEncoder(w).Encode(body)
}

func orDefault(v any, def string) any {
	if s, ok := v.(string); ok && s != "" {
		return s
	}
	return def
}

// str renders any as a display string (missing keys -> "").
func str(v any) string {
	s, _ := v.(string)
	return s
}

// hasAnyKey reports whether any of the keys holds a non-empty string.
func hasAnyKey(m map[string]any, keys ...string) bool {
	for _, k := range keys {
		if str(m[k]) != "" {
			return true
		}
	}
	return false
}