package netboxgo

import (
	"bytes"
	"context"
	"crypto/tls"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/url"
	"strings"
	"time"

	"github.com/pkg/errors"
)

// Client struct is used to create a new NetBox endpoint
type Client struct {
	// DCIM           *DCIM
	// Tenancy        *Tenancy
	// IPAM           *IPAM
	// Virtualization *Virtualization
	// Secret         *Secret

	Tenants         *TenantsService
	Sites           *SitesService
	SiteGroups      *SiteGroupsService
	VirtualMachines *VirtualMachinesService
	Clusters        *ClustersService
	VLANs           *VLANsService
	Secrets         *SecretsService
	InventoryItems  *InventoryItemsService
	Devices         *DevicesService
	DeviceRoles     *DeviceRolesService
	DeviceTypes     *DeviceTypesService
	Interfaces      *InterfacesService
	Prefixes        *PrefixesService
	VRFs            *VRFsService
	RearPorts       *RearPortsService

	// baseURL is the URL used for the base URL of the API
	baseURL *url.URL

	// httpClient is used for HTTP requests
	httpClient *http.Client

	// Reuse a single struct instead of allocating one for each service on the heap.
	common service

	// UserAgent is used to set the UserAgent on the HTTP requests
	UserAgent string

	// Token is set for authentication of the API
	Token string

	// TokenPrefix is optional to set token prefix other than "Token"
	TokenPrefix string

	// SessionKey is used to read authentication data
	SessionKey string

	// Used by golang wasm
	FetchMode string

	// Debug enables verbose debugging messages to console.
	Debug bool

	// InsecureSkipVerify is used to selectively skip InsecureVerifications
	InsecureSkipVerify bool
}

type service struct {
	client *Client
}

const (
	circuitsPath       = "/circuits"
	dcimPath           = "/dcim"
	extrasPath         = "/extras"
	ipamPath           = "/ipam"
	tenancyPath        = "/tenancy"
	usersPath          = "/users"
	virtualizationPath = "/virtualization"
)

// NetBoxSessionKey sets the session key for secrets retrieval
type NetBoxSessionKey struct {
	XSessionKey string `json:"session_key"`
}

// NewClient returns a new NetBox API client
func NewClient(apiurl string, httpClient *http.Client) (*Client, error) {
	c := &Client{}

	api, err := url.Parse(apiurl)
	if err != nil {
		return c, fmt.Errorf("unable to parse url %s: %w", apiurl, err)
	}

	c.baseURL = api
	c.SetDebug(false)
	c.SetUserAgent("netboxgo/0.0.6")
	c.httpClient = httpClient

	if httpClient == nil {
		transport := &http.Transport{
			TLSClientConfig: &tls.Config{
				InsecureSkipVerify: false,
				CipherSuites: []uint16{
					tls.TLS_AES_128_GCM_SHA256,
					tls.TLS_AES_256_GCM_SHA384,
					tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
					tls.TLS_CHACHA20_POLY1305_SHA256,
				},
				MinVersion: tls.VersionTLS12,
			},
			Proxy: http.ProxyFromEnvironment,
		}

		timeout := time.Duration(60 * time.Second)
		c.httpClient = &http.Client{
			Transport: transport,
			Jar:       nil,
			Timeout:   timeout,
		}
	}

	c.common.client = c
	c.Clusters = (*ClustersService)(&c.common)
	c.Devices = (*DevicesService)(&c.common)
	c.DeviceRoles = (*DeviceRolesService)(&c.common)
	c.DeviceTypes = (*DeviceTypesService)(&c.common)
	c.Interfaces = (*InterfacesService)(&c.common)
	c.InventoryItems = (*InventoryItemsService)(&c.common)
	c.Prefixes = (*PrefixesService)(&c.common)
	c.RearPorts = (*RearPortsService)(&c.common)
	c.Tenants = (*TenantsService)(&c.common)
	c.Secrets = (*SecretsService)(&c.common)
	c.Sites = (*SitesService)(&c.common)
	c.SiteGroups = (*SiteGroupsService)(&c.common)
	c.VirtualMachines = (*VirtualMachinesService)(&c.common)
	c.VLANs = (*VLANsService)(&c.common)
	c.VRFs = (*VRFsService)(&c.common)

	return c, nil
}

// SetUserAgent is used to set the user agent for interaction with the API
func (c *Client) SetUserAgent(u string) {
	c.UserAgent = u
}

// SetDebug is used to toggle debugging, set to true for debug
func (c *Client) SetDebug(b bool) {
	c.Debug = b
}

// SetToken is used to set the http token bearer for interaction with the API
func (c *Client) SetToken(token string) {
	c.Token = token
}

// FetchSessionKey fetches sessionkey
func (c *Client) FetchSessionKey(privatekey string) error {
	form := url.Values{}
	form.Add("private_key", privatekey)
	query := form.Encode()

	ctx := context.Background()
	req, err := http.NewRequestWithContext(ctx, "POST", c.baseURL.String()+secretsPath+"/get-session-key/", strings.NewReader(query))
	if err != nil {
		return err
	}

	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")

	if c.FetchMode != "" {
		req.Header.Add("js.fetch:mode", "no-cors")
	}

	req.Header.Add("Authorization", " Token "+c.Token)

	var sessionkey NetBoxSessionKey

	res, err := c.do(req, &sessionkey)
	if err != nil {
		return err
	}

	if res.StatusCode != http.StatusOK {
		return errors.Errorf("response was: %d should be %d\n%s\n", res.StatusCode, http.StatusOK, res.Header)
	}

	c.SessionKey = sessionkey.XSessionKey

	return nil
}

// newRequest is used to make new request to endpoints
func (c *Client) newRequest(ctx context.Context, method, path string, query string, body interface{}) (*http.Request, error) {
	var err error

	var buf io.ReadWriter

	u := &url.URL{
		Scheme:   c.baseURL.Scheme,
		Host:     c.baseURL.Host,
		Path:     c.baseURL.Path + path,
		RawQuery: query,
	}

	if body != nil {
		buf = new(bytes.Buffer)

		err = json.NewEncoder(buf).Encode(body)
		if err != nil {
			return nil, err
		}
	}

	readBuf, _ := json.Marshal(body)
	c.debugf("debug: method:%s url:%s body:%s", method, u.String(), string(readBuf))

	req, err := http.NewRequestWithContext(ctx, method, u.String(), buf)
	if err != nil {
		return nil, err
	}

	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}

	if c.SessionKey != "" {
		req.Header.Add("X-Session-Key", c.SessionKey)
	}

	req.Header.Set("Accept", "application/json")
	if c.UserAgent != "" {
		req.Header.Set("User-Agent", c.UserAgent)
	}

	if c.Token != "" {
		req.Header.Add("Authorization", "Token "+c.Token)
	}

	if c.Token != "" && c.TokenPrefix != "" {
		req.Header.Add("Authorization", c.TokenPrefix+" "+c.Token)
	}

	if c.SessionKey != "" {
		req.Header.Add("X-Session-Key", c.SessionKey)
	}

	return req, nil
}

// do method is used to decode request response to proper struct
func (c *Client) do(req *http.Request, v interface{}) (*http.Response, error) {
	var err error

	var resp *http.Response

	resp, err = c.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("client unable to do request: %w", err)
	}

	if resp.StatusCode < 200 || resp.StatusCode > 299 {
		var data []byte

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

		return nil, fmt.Errorf("request failed: body=%s", string(data))
	}

	if v != nil {
		err = json.NewDecoder(resp.Body).Decode(v)
		if err != nil {
			return resp, fmt.Errorf("unable to decode response body: %w", err)
		}
	}

	return resp, nil
}

// debugf is used as a formtter for debugging information
func (c *Client) debugf(fmt string, v ...interface{}) {
	if c.Debug {
		log.Printf("cendot client: "+fmt, v...)
	}
}