package pages

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net"
	"net/http"
	"qurl/qurl"
	"time"
)

type apijson struct {
	URL    string `json:"url",omitempty`
	Exists bool   `json:"exists",omitempty`
	Error  string `json:"error",omitempty`
}

func (ctx *RootHandler) ServeAPI(w http.ResponseWriter, r *http.Request) {
	var (
		j apijson
		q *qurl.QURL
		err error
	)

	u := r.FormValue("url")

	if u == "" {
		j.Error = "Not a valid URL."
		goto complete
	}

	q, err = ctx.Storage.GetQURLByURL(u)
	if err != nil {
		j.Error = err.Error()
		goto complete
	}

	// Deal with URLs that already exist in the database
	if q != nil {
		j.Exists = true
		j.URL = fmt.Sprintf("https://qurl.org/%s", qurl.ToString(q.ID))
		goto complete
	}

	q = &qurl.QURL{
		URL:     u,
		Created: time.Now(),
	}
	if h, _, err := net.SplitHostPort(r.RemoteAddr); err == nil && h != "" {
		q.IP = net.ParseIP(h)
	}
	if b := r.Header.Get("User-Agent"); b != "" {
		q.Browser = b
	}

	// Check if the URL we're adding is valid
	err = q.CheckValid()
	if err != nil {
		j.Error = err.Error()
		goto complete
	}

	// Add the URL
	err = ctx.Storage.AddQURL(q)
	if err != nil {
		j.Error = err.Error()
		goto complete
	}

	j.URL = fmt.Sprintf("https://qurl.org/%s", qurl.ToString(q.ID))

complete:

	var buf bytes.Buffer
	encoder := json.NewEncoder(&buf)
	err = encoder.Encode(j)
	if err != nil {
		http.Error(w, fmt.Sprintf("JSON encoding error: %s", err.Error()),
			http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("Content-Length", fmt.Sprintf("%d", buf.Len()))
	w.Write(buf.Bytes())
}