/*
Copyright 2022 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package civocloud

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
)

// Client is the means of connecting to the Civo API service
type Client struct {
	BaseURL          *url.URL
	UserAgent        string
	APIKey           string
	Region           string
	LastJSONResponse string

	httpClient *http.Client
}

// HTTPError is the error returned when the API fails with an HTTP error
type HTTPError struct {
	Code   int
	Status string
	Reason string
}

// Result is the result of a SimpleResponse
type Result string

// SimpleResponse is a structure that returns success and/or any error
type SimpleResponse struct {
	ID           string `json:"id"`
	Result       Result `json:"result"`
	ErrorCode    string `json:"code"`
	ErrorReason  string `json:"reason"`
	ErrorDetails string `json:"details"`
}

// ResultSuccess represents a successful SimpleResponse
const ResultSuccess = "success"

func (e HTTPError) Error() string {
	return fmt.Sprintf("%d: %s, %s", e.Code, e.Status, e.Reason)
}

// NewClientWithURL initializes a Client with a specific API URL
func NewClientWithURL(apiKey, civoAPIURL, region string) (*Client, error) {
	if apiKey == "" {
		err := errors.New("no API Key supplied, this is required")
		return nil, NoAPIKeySuppliedError.wrap(err)
	}
	parsedURL, err := url.Parse(civoAPIURL)
	if err != nil {
		return nil, err
	}

	var httpTransport = &http.Transport{
		Proxy: http.ProxyFromEnvironment,
	}

	client := &Client{
		BaseURL:   parsedURL,
		UserAgent: "autoscaler",
		APIKey:    apiKey,
		Region:    region,
		httpClient: &http.Client{
			Transport: httpTransport,
		},
	}
	return client, nil
}

// NewClient initializes a Client connecting to the production API
func NewClient(apiKey, region string) (*Client, error) {
	return NewClientWithURL(apiKey, "https://api.civo.com", region)
}

// NewAdvancedClientForTesting initializes a Client connecting to a local test server and allows for specifying methods
func NewAdvancedClientForTesting(responses map[string]map[string]string) (*Client, *httptest.Server, error) {
	var responseSent bool

	server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		body, err := ioutil.ReadAll(req.Body)
		if err != nil {
			log.Printf("Error reading body: %v", err)
			return
		}

		req.Body = ioutil.NopCloser(bytes.NewBuffer(body))

		for url, criteria := range responses {
			if strings.Contains(req.URL.String(), url) &&
				req.Method == criteria["method"] {
				if criteria["method"] == "PUT" || criteria["method"] == "POST" || criteria["method"] == "PATCH" {
					if strings.TrimSpace(string(body)) == strings.TrimSpace(criteria["requestBody"]) {
						responseSent = true
						rw.Write([]byte(criteria["responseBody"]))
					}
				} else {
					responseSent = true
					rw.Write([]byte(criteria["responseBody"]))
				}
			}
		}

		if !responseSent {
			fmt.Println("Failed to find a matching request!")
			fmt.Println("Request body:", string(body))
			fmt.Println("Method:", req.Method)
			fmt.Println("URL:", req.URL.String())
			rw.Write([]byte(`{"result": "failed to find a matching request"}`))
		}
	}))

	client, err := NewClientForTestingWithServer(server)

	return client, server, err
}

// NewClientForTesting initializes a Client connecting to a local test server
func NewClientForTesting(responses map[string]string) (*Client, *httptest.Server, error) {
	var responseSent bool

	server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		for url, response := range responses {
			if strings.Contains(req.URL.String(), url) {
				responseSent = true
				rw.Write([]byte(response))
			}
		}

		if !responseSent {
			fmt.Println("Failed to find a matching request!")
			fmt.Println("URL:", req.URL.String())

			rw.Write([]byte(`{"result": "failed to find a matching request"}`))
		}
	}))

	client, err := NewClientForTestingWithServer(server)

	return client, server, err
}

// NewClientForTestingWithServer initializes a Client connecting to a passed-in local test server
func NewClientForTestingWithServer(server *httptest.Server) (*Client, error) {
	client, err := NewClientWithURL("TEST-API-KEY", server.URL, "TEST")
	if err != nil {
		return nil, err
	}
	client.httpClient = server.Client()
	return client, err
}

func (c *Client) prepareClientURL(requestURL string) *url.URL {
	u, _ := url.Parse(c.BaseURL.String() + requestURL)
	return u
}

func (c *Client) sendRequest(req *http.Request) ([]byte, error) {
	req.Header.Set("Accept", "application/json")
	req.Header.Set("User-Agent", c.UserAgent)
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("bearer %s", c.APIKey))

	if req.Method == "GET" || req.Method == "DELETE" {
		// add the region param
		param := req.URL.Query()
		param.Add("region", c.Region)
		req.URL.RawQuery = param.Encode()
	}

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

	body, err := ioutil.ReadAll(resp.Body)
	c.LastJSONResponse = string(body)

	if resp.StatusCode >= 300 {
		return nil, HTTPError{Code: resp.StatusCode, Status: resp.Status, Reason: string(body)}
	}

	return body, err
}

// SendGetRequest sends a correctly authenticated get request to the API server
func (c *Client) SendGetRequest(requestURL string) ([]byte, error) {
	u := c.prepareClientURL(requestURL)
	req, err := http.NewRequest("GET", u.String(), nil)
	if err != nil {
		return nil, err
	}

	return c.sendRequest(req)
}

// SendPostRequest sends a correctly authenticated post request to the API server
func (c *Client) SendPostRequest(requestURL string, params interface{}) ([]byte, error) {
	u := c.prepareClientURL(requestURL)

	// we create a new buffer and encode everything to json to send it in the request
	jsonValue, _ := json.Marshal(params)

	req, err := http.NewRequest("POST", u.String(), bytes.NewBuffer(jsonValue))
	if err != nil {
		return nil, err
	}
	return c.sendRequest(req)
}

// SendPutRequest sends a correctly authenticated put request to the API server
func (c *Client) SendPutRequest(requestURL string, params interface{}) ([]byte, error) {
	u := c.prepareClientURL(requestURL)

	// we create a new buffer and encode everything to json to send it in the request
	jsonValue, _ := json.Marshal(params)

	req, err := http.NewRequest("PUT", u.String(), bytes.NewBuffer(jsonValue))
	if err != nil {
		return nil, err
	}
	return c.sendRequest(req)
}

// SendDeleteRequest sends a correctly authenticated delete request to the API server
func (c *Client) SendDeleteRequest(requestURL string) ([]byte, error) {
	u := c.prepareClientURL(requestURL)
	req, err := http.NewRequest("DELETE", u.String(), nil)
	if err != nil {
		return nil, err
	}

	return c.sendRequest(req)
}

// DecodeSimpleResponse parses a response body in to a SimpleResponse object
func (c *Client) DecodeSimpleResponse(resp []byte) (*SimpleResponse, error) {
	response := SimpleResponse{}
	err := json.NewDecoder(bytes.NewReader(resp)).Decode(&response)
	return &response, err
}