package viewer

import (
	"io"
	"net/http"
	"strings"

	"reanimator/chart/web"
)

type HandlerOptions struct {
	Title string
}

func NewHandler(opts HandlerOptions) http.Handler {
	title := strings.TrimSpace(opts.Title)
	if title == "" {
		title = "Reanimator Chart"
	}

	mux := http.NewServeMux()
	mux.Handle("GET /static/", http.StripPrefix("/static/", web.Static()))
	mux.HandleFunc("GET /healthz", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("ok"))
	})
	mux.HandleFunc("GET /", func(w http.ResponseWriter, r *http.Request) {
		html, err := RenderHTML(nil, title)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		_, _ = w.Write(html)
	})
	mux.HandleFunc("POST /render", func(w http.ResponseWriter, r *http.Request) {
		var payload string
		if strings.Contains(r.Header.Get("Content-Type"), "application/json") {
			body, err := io.ReadAll(r.Body)
			if err != nil {
				http.Error(w, err.Error(), http.StatusBadRequest)
				return
			}
			payload = string(body)
		} else {
			if err := r.ParseForm(); err != nil {
				http.Error(w, err.Error(), http.StatusBadRequest)
				return
			}
			payload = r.FormValue("snapshot")
		}

		page, err := buildPageData([]byte(payload), title)
		if err != nil {
			page = pageData{
				Title:     title,
				Error:     err.Error(),
				InputJSON: prettyJSON(payload),
			}
		} else {
			page.InputJSON = prettyJSON(payload)
		}

		html, renderErr := web.Render(page)
		if renderErr != nil {
			http.Error(w, renderErr.Error(), http.StatusInternalServerError)
			return
		}
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		_, _ = w.Write(html)
	})
	return mux
}