// Search: GET /search.json — full-text search across posts, topics,
// users and categories. The term supports Discourse's search operators
// (@user, #category, order:latest, ...); they pass through untouched.
package discourse

import (
	"context"
	"fmt"
	"net/url"
	"strconv"
	"strings"
)

// SearchRequest is the GET /search.json query. Term is required; Page is
// 1-based (0 means "leave unset" — Discourse then returns page 1).
type SearchRequest struct {
	Term string
	Page int
}

// SearchPost is one post hit: the match lives in Blurb (a plain-text
// excerpt around the match) while TopicTitleHeadline carries the topic
// title with <em> highlights around matched words.
type SearchPost struct {
	ID                 int    `json:"id"`
	TopicID            int    `json:"topic_id"`
	PostNumber         int    `json:"post_number"`
	Username           string `json:"username"`
	Name               string `json:"name"`
	Blurb              string `json:"blurb"`
	TopicTitleHeadline string `json:"topic_title_headline"`
	CreatedAt          string `json:"created_at"`
	LikeCount          int    `json:"like_count"`
}

// SearchTopic is one topic hit.
type SearchTopic struct {
	ID    int    `json:"id"`
	Title string `json:"title"`
	Slug  string `json:"slug"`
}

// SearchUser is one user hit.
type SearchUser struct {
	ID       int    `json:"id"`
	Username string `json:"username"`
	Name     string `json:"name"`
}

// SearchResult groups the four hit lists Discourse returns; whichever
// classes matched are non-empty, the rest are nil.
type SearchResult struct {
	Posts      []SearchPost  `json:"posts"`
	Topics     []SearchTopic `json:"topics"`
	Users      []SearchUser  `json:"users"`
	Categories []Category    `json:"categories"`
}

// Search runs a full-text search and returns the grouped hits.
func (c *Client) Search(ctx context.Context, req SearchRequest) (*SearchResult, error) {
	if strings.TrimSpace(req.Term) == "" {
		return nil, fmt.Errorf("%w: search term is required", ErrInvalidRequest)
	}
	q := url.Values{}
	q.Set("term", req.Term)
	if req.Page > 1 {
		q.Set("page", strconv.Itoa(req.Page))
	}
	var res SearchResult
	if err := c.Get(ctx, "/search.json?"+q.Encode(), &res); err != nil {
		return nil, err
	}
	return &res, nil
}