package pocketbase

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"time"
)

// Client handles interactions with the PocketBase API.
type Client struct {
	baseURL  string
	user     string
	password string
	category string
	http     *http.Client
}

// New creates a new PocketBase client.
func New(baseURL, user, password, category string) *Client {
	// Normalise: ensure baseURL does not already end with /api.
	baseURL = strings.TrimSuffix(baseURL, "/api")
	baseURL = strings.TrimSuffix(baseURL, "/")
	return &Client{
		baseURL:  baseURL,
		user:     user,
		password: password,
		category: category,
		http: &http.Client{
			Timeout: 30 * time.Second,
		},
	}
}

type authRequest struct {
	Identity string `json:"identity"`
	Password string `json:"password"`
}

type authResponse struct {
	Token string `json:"token"`
}

type record struct {
	URL string `json:"url"`
}

type recordsResponse struct {
	Items []record `json:"items"`
}

// GetBookmarkURLs authenticates and retrieves URLs from the bookmarks collection.
func (c *Client) GetBookmarkURLs(ctx context.Context) ([]string, error) {
	token, err := c.authenticate(ctx)
	if err != nil {
		return nil, fmt.Errorf("pocketbase auth: %w", err)
	}

	urls, err := c.fetchURLs(ctx, token)
	if err != nil {
		return nil, fmt.Errorf("pocketbase fetch URLs: %w", err)
	}

	return urls, nil
}

func (c *Client) authenticate(ctx context.Context) (string, error) {
	reqBody, err := json.Marshal(authRequest{
		Identity: c.user,
		Password: c.password,
	})
	if err != nil {
		return "", err
	}

	authURL := c.baseURL + "/api/collections/users/auth-with-password"
	req, err := http.NewRequestWithContext(ctx, "POST", authURL, bytes.NewBuffer(reqBody))
	if err != nil {
		return "", err
	}
	req.Header.Set("Content-Type", "application/json")

	resp, err := c.http.Do(req)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("unexpected status: %d", resp.StatusCode)
	}

	var authResp authResponse
	if err := json.NewDecoder(resp.Body).Decode(&authResp); err != nil {
		return "", err
	}

	return authResp.Token, nil
}

func (c *Client) fetchURLs(ctx context.Context, token string) ([]string, error) {
	// Filter: category=<value>, perPage=200, fields=url
	filter := fmt.Sprintf(`category="%s"`, c.category)
	u, err := url.Parse(c.baseURL + "/api/collections/bookmarks/records")
	if err != nil {
		return nil, fmt.Errorf("invalid base URL: %w", err)
	}
	q := u.Query()
	q.Set("filter", filter)
	q.Set("perPage", "200")
	q.Set("fields", "url")
	u.RawQuery = q.Encode()

	req, err := http.NewRequestWithContext(ctx, "GET", u.String(), nil)
	if err != nil {
		return nil, fmt.Errorf("creating request: %w", err)
	}
	req.Header.Set("Authorization", token)

	resp, err := c.http.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("unexpected status: %d", resp.StatusCode)
	}

	var recs recordsResponse
	if err := json.NewDecoder(resp.Body).Decode(&recs); err != nil {
		return nil, err
	}

	var urls []string
	for _, r := range recs.Items {
		if r.URL != "" {
			urls = append(urls, r.URL)
		}
	}

	return urls, nil
}