/*
 *	Scope - A simple and minimal metasearch engine
 *	Copyright (C) 2021 Arsen Musayelyan
 *
 *	This program is free software: you can redistribute it and/or modify
 *	it under the terms of the GNU Affero General Public License as published by
 *	the Free Software Foundation, either version 3 of the License, or
 *	(at your option) any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU Affero General Public License for more details.
 *
 *	You should have received a copy of the GNU Affero General Public License
 *	along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package cards

import (
	"encoding/json"
	"fmt"
	"html/template"
	"net/http"
	"net/url"
	"time"
)

func init() {
	Register("ddg", 3, NewDDGCard)
}

// ddgAttribution is HTML for attribution of DuckDuckGo at their request
const ddgAttribution = `<p class="is-size-7 pt-2">
	<span class="iconify" data-icon="simple-icons:duckduckgo" data-inline="true"></span>&nbsp;
    Results from
    <a href="https://duckduckgo.com/%s">DuckDuckGo &raquo;</a>
</p>`

// DDGCard represents a DuckDuckGo Instant Answer API card
type DDGCard struct {
	query     string
	userAgent string
	resp      DDGInstAns
}

// DDGInstAns represents a DuckDuckGo Instant Answer API response
type DDGInstAns struct {
	Abstract       string
	AbstractText   string
	AbstractSource string
	AbstractURL    string
	Image          string
	Heading        string
	Answer         string
	AnswerType     string
}

// NewDDGCard is a NewCardFunc that creates a new DDGCard
func NewDDGCard(query, userAgent string) Card {
	return &DDGCard{
		query:     url.QueryEscape(query),
		userAgent: userAgent,
	}
}

// RunQuery requests the query from the instant answer API
func (ddg *DDGCard) RunQuery() error {
	http.DefaultClient.Timeout = 5 * time.Second

	// Create new API request
	req, err := http.NewRequest(
		http.MethodGet,
		"https://api.duckduckgo.com/?q="+ddg.query+"&format=json",
		nil,
	)
	if err != nil {
		return err
	}
	req.Header.Set("User-Agent", ddg.userAgent)

	// Perform request
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}

	// Decode response into response struct
	err = json.NewDecoder(res.Body).Decode(&ddg.resp)
	if err != nil {
		return err
	}

	return nil
}

// Returned checks if abstract is empty.
// If it is, query returned no result.
func (ddg *DDGCard) Returned() bool {
	// Value was returned if abstract is not empty
	return ddg.resp.Abstract != ""
}

// Matches always returns true as there are no keys
func (ddg *DDGCard) Matches() bool {
	return true
}

// StripKey returns the query as there are no keys
func (ddg *DDGCard) StripKey() string {
	// No key to strip, so return query
	return ddg.query
}

// Title returns the instant answer heading
func (ddg *DDGCard) Title() string {
	return ddg.resp.Heading
}

// Content returns the instant answer abstract with
// DuckDuckGo attibution
func (ddg *DDGCard) Content() template.HTML {
	// Return abstract with attribution
	return template.HTML(ddg.resp.Abstract + fmt.Sprintf(ddgAttribution, ddg.query))
}

// Footer returns a footer containing URL and name of source
// gotten from instant answer API
func (ddg *DDGCard) Footer() template.HTML {
	// Return footer with abstract url and source
	return template.HTML(fmt.Sprintf(
		`<div class="card-footer"><a class="card-footer-item" href="%s">%s</a></div>`,
		ddg.resp.AbstractURL,
		ddg.resp.AbstractSource,
	))
}

// Head returns an empty string as no extra tags are reuired
// for DDGCard
func (ddg *DDGCard) Head() template.HTML {
	return ""
}