package reddit

import (
	"context"
	"fmt"
	"time"

	"github.com/vartanbeno/go-reddit/v2/reddit"

	"somegit.dev/vikingowl/reddit-reader/internal/domain"
)

// Fetcher is the interface for fetching posts from a subreddit.
type Fetcher interface {
	FetchPosts(ctx context.Context, subreddit, sort string, limit int) ([]domain.Post, error)
}

// Client wraps the go-reddit client behind the Fetcher interface.
type Client struct {
	rc *reddit.Client
}

// NewClient creates an authenticated Reddit API client.
func NewClient(clientID, clientSecret, username, password string) (*Client, error) {
	rc, err := reddit.NewClient(reddit.Credentials{
		ID:       clientID,
		Secret:   clientSecret,
		Username: username,
		Password: password,
	})
	if err != nil {
		return nil, fmt.Errorf("create reddit client: %w", err)
	}
	return &Client{rc: rc}, nil
}

// FetchPosts retrieves posts from the given subreddit using the specified sort order.
// Supported sort values: "hot", "top", "rising", and anything else defaults to "new".
func (c *Client) FetchPosts(ctx context.Context, subreddit, sort string, limit int) ([]domain.Post, error) {
	listOpts := &reddit.ListOptions{Limit: limit}
	listPostOpts := &reddit.ListPostOptions{ListOptions: *listOpts}

	var posts []*reddit.Post
	var err error

	switch sort {
	case "hot":
		posts, _, err = c.rc.Subreddit.HotPosts(ctx, subreddit, listOpts)
	case "top":
		posts, _, err = c.rc.Subreddit.TopPosts(ctx, subreddit, listPostOpts)
	case "rising":
		posts, _, err = c.rc.Subreddit.RisingPosts(ctx, subreddit, listOpts)
	default:
		posts, _, err = c.rc.Subreddit.NewPosts(ctx, subreddit, listOpts)
	}
	if err != nil {
		return nil, fmt.Errorf("fetch %s/%s: %w", subreddit, sort, err)
	}

	result := make([]domain.Post, len(posts))
	for i, p := range posts {
		var created time.Time
		if p.Created != nil {
			created = p.Created.Time
		}
		result[i] = domain.Post{
			ID:         p.FullID,
			Subreddit:  p.SubredditName,
			Title:      p.Title,
			Author:     p.Author,
			URL:        p.URL,
			SelfText:   p.Body,
			Score:      p.Score,
			CreatedUTC: created,
		}
	}
	return result, nil
}