// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0

package couchdbreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/couchdbreceiver"

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strconv"

	"go.opentelemetry.io/collector/component"
	"go.uber.org/zap"
)

// client defines the basic HTTP client interface.
type client interface {
	Get(path string) ([]byte, error)
	GetStats(nodeName string) (map[string]any, error)
}

var _ client = (*couchDBClient)(nil)

type couchDBClient struct {
	client *http.Client
	cfg    *Config
	logger *zap.Logger
}

// newCouchDBClient creates a new client to make requests for the CouchDB receiver.
func newCouchDBClient(cfg *Config, host component.Host, settings component.TelemetrySettings) (client, error) {
	client, err := cfg.ToClient(host, settings)
	if err != nil {
		return nil, fmt.Errorf("failed to create HTTP Client: %w", err)
	}

	return &couchDBClient{
		client: client,
		cfg:    cfg,
		logger: settings.Logger,
	}, nil
}

// Get issues an authorized Get requests to the specified url.
func (c *couchDBClient) Get(path string) ([]byte, error) {
	req, err := c.buildReq(path)
	if err != nil {
		return nil, err
	}

	resp, err := c.client.Do(req)
	if err != nil {
		return nil, err
	}

	defer func() {
		if err = resp.Body.Close(); err != nil {
			c.logger.Warn("failed to close response body", zap.Error(err))
		}
	}()

	if resp.StatusCode != http.StatusOK {
		if resp.StatusCode >= 400 {
			c.logger.Error("couchdb", zap.Error(err), zap.String("status_code", strconv.Itoa(resp.StatusCode)))
		}
		return nil, fmt.Errorf("request GET %s failed - %q", req.URL.String(), resp.Status)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response body %w", err)
	}

	return body, nil
}

// GetStats gets couchdb stats at a specific node name endpoint.
func (c *couchDBClient) GetStats(nodeName string) (map[string]any, error) {
	path := fmt.Sprintf("/_node/%s/_stats/couchdb", nodeName)
	body, err := c.Get(path)
	if err != nil {
		return nil, err
	}

	var stats map[string]any
	err = json.Unmarshal(body, &stats)
	if err != nil {
		return nil, err
	}

	return stats, nil
}

func (c *couchDBClient) buildReq(path string) (*http.Request, error) {
	url := c.cfg.Endpoint + path
	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/json")
	req.SetBasicAuth(c.cfg.Username, string(c.cfg.Password))
	return req, nil
}