package web

import (
	"html/template"
	"net/http"
)

// ConvoyFetcher defines the interface for fetching convoy data.
type ConvoyFetcher interface {
	FetchConvoys() ([]ConvoyRow, error)
	FetchMergeQueue() ([]MergeQueueRow, error)
	FetchPolecats() ([]PolecatRow, error)
}

// ConvoyHandler handles HTTP requests for the convoy dashboard.
type ConvoyHandler struct {
	fetcher  ConvoyFetcher
	template *template.Template
}

// NewConvoyHandler creates a new convoy handler with the given fetcher.
func NewConvoyHandler(fetcher ConvoyFetcher) (*ConvoyHandler, error) {
	tmpl, err := LoadTemplates()
	if err != nil {
		return nil, err
	}

	return &ConvoyHandler{
		fetcher:  fetcher,
		template: tmpl,
	}, nil
}

// ServeHTTP handles GET / requests and renders the convoy dashboard.
func (h *ConvoyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	convoys, err := h.fetcher.FetchConvoys()
	if err != nil {
		http.Error(w, "Failed to fetch convoys", http.StatusInternalServerError)
		return
	}

	mergeQueue, err := h.fetcher.FetchMergeQueue()
	if err != nil {
		// Non-fatal: show convoys even if merge queue fails
		mergeQueue = nil
	}

	polecats, err := h.fetcher.FetchPolecats()
	if err != nil {
		// Non-fatal: show convoys even if polecats fail
		polecats = nil
	}

	data := ConvoyData{
		Convoys:    convoys,
		MergeQueue: mergeQueue,
		Polecats:   polecats,
	}

	w.Header().Set("Content-Type", "text/html; charset=utf-8")

	if err := h.template.ExecuteTemplate(w, "convoy.html", data); err != nil {
		http.Error(w, "Failed to render template", http.StatusInternalServerError)
		return
	}
}