package httpapi

import (
	"net/http"

	"github.com/metamorphosis-dev/kafka/internal/contracts"
	"github.com/metamorphosis-dev/kafka/internal/search"
	"github.com/metamorphosis-dev/kafka/internal/views"
)

type Handler struct {
	searchSvc *search.Service
}

func NewHandler(searchSvc *search.Service) *Handler {
	return &Handler{searchSvc: searchSvc}
}

func (h *Handler) Healthz(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
	w.WriteHeader(http.StatusOK)
	_, _ = w.Write([]byte("OK"))
}

// Index renders the homepage with the search box.
func (h *Handler) Index(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		http.NotFound(w, r)
		return
	}
	if err := views.RenderIndex(w); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}

// OpenSearch serves the OpenSearch description XML.
func (h *Handler) OpenSearch(baseURL string) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		xml, err := views.OpenSearchXML(baseURL)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		w.Header().Set("Content-Type", "application/opensearchdescription+xml; charset=utf-8")
		w.Write(xml)
	}
}

func (h *Handler) Search(w http.ResponseWriter, r *http.Request) {
	// For HTML format with no query, redirect to homepage.
	if r.FormValue("q") == "" && (r.FormValue("format") == "" || r.FormValue("format") == "html") {
		http.Redirect(w, r, "/", http.StatusFound)
		return
	}

	req, err := search.ParseSearchRequest(r)
	if err != nil {
		// For HTML, render error on the results page.
		if req.Format == contracts.FormatHTML || r.FormValue("format") == "html" {
			pd := views.PageData{Query: r.FormValue("q")}
			if views.IsHTMXRequest(r) {
				views.RenderSearchFragment(w, pd)
			} else {
				views.RenderSearch(w, pd)
			}
			return
		}
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	resp, err := h.searchSvc.Search(r.Context(), req)
	if err != nil {
		if req.Format == contracts.FormatHTML {
			pd := views.PageData{Query: req.Query}
			if views.IsHTMXRequest(r) {
				views.RenderSearchFragment(w, pd)
			} else {
				views.RenderSearch(w, pd)
			}
			return
		}
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	if req.Format == contracts.FormatHTML {
		pd := views.FromResponse(resp, req.Query, req.Pageno)
		if err := views.RenderSearchAuto(w, r, pd); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
		}
		return
	}

	if err := search.WriteSearchResponse(w, req.Format, resp); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}