package server

import (
	"encoding/json"
	"io"
	"log"
	"net/http"
	"runtime/debug"

	"github.com/gorilla/mux"
)

type ApiError struct {
	Err    string
	Status int
}

func (e ApiError) Error() string {
	return e.Err
}

type apiFunc func(Context) error

func MakeHTTPHandler(f apiFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		ctx := Context{w, r}
		if err := f(ctx); err != nil {
			if e, ok := err.(ApiError); ok {
				log.Println("API ERROR: ", e.Error(), e.Status)
				ctx.WriteJSON(e.Status, e)
				return
			}
			log.Println("INTERNAL ERROR: ", err)
			debug.PrintStack()
			ctx.WriteJSON(500, &ApiError{Err: "internal error", Status: http.StatusInternalServerError})
			return
		}
	}
}

type Context struct {
	W http.ResponseWriter
	R *http.Request
}

func (c Context) GetVar(name string) string {
	vars := mux.Vars(c.R)
	val, ok := vars[name]
	if ok {
		return val
	}
	return ""
}

func (c Context) Header(header string, value string) *Context {
	c.W.Header().Add(header, value)
	return &c
}

func (c Context) ContentType(contentType string) *Context {
	return c.Header("Content-Type", contentType)
}

func (c Context) Status(status int) *Context {
	c.W.WriteHeader(status)
	return &c
}

func (c Context) WriteJSON(status int, v any) error {
	c.ContentType("application/json").Status(status)
	return json.NewEncoder(c.W).Encode(v)
}

func (c Context) WritePlain(status int, text string) error {
	c.ContentType("text/plain").Status(status)
	_, err := c.W.Write([]byte(text))
	return err
}

func (c Context) WriteBlob(status int, contentType string, blob []byte) error {
	c.ContentType(contentType).Status(status)
	_, err := c.W.Write(blob)
	return err
}

func DecodeJSON(r io.Reader, v any) error {
	return json.NewDecoder(r).Decode(v)
}