package goblocks

import (
	"encoding/json"
	"log/slog"
	"net/http"
	"strings"
)

type stringWriter struct {
	builder strings.Builder
	header  http.Header
}

func newStringWriter() *stringWriter {
	return &stringWriter{
		header: make(http.Header),
	}
}

func (w *stringWriter) Header() http.Header {
	return w.header
}

func (w *stringWriter) Write(b []byte) (int, error) {
	return w.builder.Write(b)
}

func (w *stringWriter) WriteHeader(statusCode int) {}

func (a *App) JSON(w http.ResponseWriter, code int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(code)
	json.NewEncoder(w).Encode(v)
}

func (a *App) HTML(w http.ResponseWriter, code int, name string, td *TemplateData) {
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.WriteHeader(code)
	err := a.Templates.Template(w, name, td)
	if err != nil {
		slog.Error("error rendering template", "error", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

func (a *App) RenderHTML(name string, td *TemplateData) (string, error) {
	sw := newStringWriter()
	err := a.Templates.Template(sw, name, td)
	if err != nil {
		slog.Error("error rendering template", "error", err)
		return "", err
	}
	return sw.builder.String(), nil
}