// Package arr contains the HTTP client and types shared by the Radarr and Sonarr clients.
package arr

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

// Client is a minimal JSON client for the Radarr/Sonarr v3 API.
type Client struct {
	baseURL string
	apiKey  string
	http    *http.Client
}

// NewClient returns a client for the instance at baseURL (without /api/v3).
func NewClient(baseURL, apiKey string) *Client {
	return &Client{
		baseURL: strings.TrimRight(baseURL, "/"),
		apiKey:  apiKey,
		http:    &http.Client{Timeout: 2 * time.Minute}, // interactive release searches query every indexer
	}
}

// APIError is returned for non-2xx responses.
type APIError struct {
	Status  int
	Message string
}

func (e *APIError) Error() string {
	if e.Message == "" {
		return fmt.Sprintf("unexpected response: HTTP %d", e.Status)
	}
	return fmt.Sprintf("HTTP %d: %s", e.Status, e.Message)
}

// Do sends a request to /api/v3/<path>. body (if non-nil) is JSON-encoded and
// the response is decoded into out (if non-nil).
func (c *Client) Do(ctx context.Context, method, path string, query url.Values, body, out any) error {
	u := c.baseURL + "/api/v3/" + strings.TrimLeft(path, "/")
	if len(query) > 0 {
		u += "?" + query.Encode()
	}

	var rd io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			return fmt.Errorf("encoding request: %w", err)
		}
		rd = bytes.NewReader(b)
	}

	req, err := http.NewRequestWithContext(ctx, method, u, rd)
	if err != nil {
		return err
	}
	req.Header.Set("X-Api-Key", c.apiKey)
	req.Header.Set("Accept", "application/json")
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}

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

	if resp.StatusCode < 200 || resp.StatusCode > 299 {
		return &APIError{Status: resp.StatusCode, Message: errorMessage(resp.Body)}
	}
	if out == nil {
		return nil
	}
	if err := json.NewDecoder(resp.Body).Decode(out); err != nil {
		return fmt.Errorf("decoding response: %w", err)
	}
	return nil
}

// stripURL drops the request URL from transport errors so nothing sensitive
// (e.g. a proxy-added key) ends up in the UI; the host stays in the message.
func stripURL(err error) error {
	var ue *url.Error
	if errors.As(err, &ue) {
		return fmt.Errorf("%s: %w", ue.Op, ue.Err)
	}
	return err
}

// errorMessage extracts a readable message from Radarr/Sonarr error bodies,
// which are either {"message": "..."} or a list of validation failures.
func errorMessage(r io.Reader) string {
	data, _ := io.ReadAll(io.LimitReader(r, 64<<10))

	var single struct {
		Message string `json:"message"`
	}
	if json.Unmarshal(data, &single) == nil && single.Message != "" {
		return single.Message
	}
	var list []struct {
		PropertyName string `json:"propertyName"`
		ErrorMessage string `json:"errorMessage"`
	}
	if json.Unmarshal(data, &list) == nil && len(list) > 0 {
		msgs := make([]string, 0, len(list))
		for _, e := range list {
			msgs = append(msgs, e.ErrorMessage)
		}
		return strings.Join(msgs, "; ")
	}
	return strings.TrimSpace(string(data[:min(len(data), 200)]))
}