package main

import (
	"context"
	"encoding/json"
	"log"
	"net/http"
	"os"

	"google.golang.org/genai"
)

var geminiClient *genai.Client

func main() {
	loadDotEnv(".env")

	ctx := context.Background()
	client, err := genai.NewClient(ctx, &genai.ClientConfig{
		APIKey:  os.Getenv("GEMINI_API_KEY"),
		Backend: genai.BackendGeminiAPI,
	})
	if err != nil {
		log.Fatalf("failed to create genai client: %v", err)
	}
	geminiClient = client

	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
	}

	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("ok"))
	})
	http.HandleFunc("/api/video-meta", handleVideoMeta)
	http.HandleFunc("/api/search", handleSearch)
	http.HandleFunc("/api/chat", handleChat)
	http.HandleFunc("/api/unlock", handleUnlock)
	http.Handle("/", http.FileServer(http.Dir("web")))

	log.Printf("listening on :%s", port)
	if err := http.ListenAndServe(":"+port, nil); err != nil {
		log.Fatal(err)
	}
}

func handleVideoMeta(w http.ResponseWriter, r *http.Request) {
	id := r.URL.Query().Get("id")
	if id == "" {
		http.Error(w, "missing id", http.StatusBadRequest)
		return
	}
	meta, err := fetchVideoMeta(id, os.Getenv("YOUTUBE_API_KEY"))
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadGateway)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(meta)
}

func handleSearch(w http.ResponseWriter, r *http.Request) {
	query := r.URL.Query().Get("q")
	if query == "" {
		http.Error(w, "missing q", http.StatusBadRequest)
		return
	}
	results, err := searchVideos(query, os.Getenv("YOUTUBE_API_KEY"))
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadGateway)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(results)
}

type chatRequest struct {
	VideoTitle       string     `json:"videoTitle"`
	VideoDescription string     `json:"videoDescription"`
	History          []chatTurn `json:"history"`
	Message          string     `json:"message"`
	UnlockCode       string     `json:"unlockCode"`
	Persona          string     `json:"persona"`
}

type chatStreamEvent struct {
	Type            string         `json:"type"` // "status" | "final" | "error"
	Text            string         `json:"text,omitempty"`
	Reply           string         `json:"reply,omitempty"`
	Model           string         `json:"model,omitempty"`
	Videos          []searchResult `json:"videos,omitempty"`
	AutoPlayVideoID string         `json:"autoPlayVideoId,omitempty"`
}

func handleChat(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}
	var req chatRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "bad request", http.StatusBadRequest)
		return
	}

	w.Header().Set("Content-Type", "application/x-ndjson")
	flusher, _ := w.(http.Flusher)
	encoder := json.NewEncoder(w)

	writeEvent := func(ev chatStreamEvent) {
		encoder.Encode(ev)
		if flusher != nil {
			flusher.Flush()
		}
	}

	model := selectModel(req.UnlockCode, os.Getenv("UNLOCK_CODE"))
	outcome, err := chatReply(r.Context(), geminiClient, model, os.Getenv("YOUTUBE_API_KEY"), req.VideoTitle, req.VideoDescription, req.Persona, req.History, req.Message, func(status string) {
		writeEvent(chatStreamEvent{Type: "status", Text: status})
	})
	if err != nil {
		writeEvent(chatStreamEvent{Type: "error", Text: err.Error()})
		return
	}

	writeEvent(chatStreamEvent{
		Type:            "final",
		Reply:           outcome.Reply,
		Model:           outcome.Model,
		Videos:          outcome.Videos,
		AutoPlayVideoID: outcome.AutoPlayVideoID,
	})
}

type unlockRequest struct {
	Code string `json:"code"`
}

type unlockResponse struct {
	Ok    bool   `json:"ok"`
	Model string `json:"model"`
}

func handleUnlock(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}
	var req unlockRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "bad request", http.StatusBadRequest)
		return
	}
	model := selectModel(req.Code, os.Getenv("UNLOCK_CODE"))
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(unlockResponse{Ok: model == modelGemini, Model: model})
}