package lfsapi

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"regexp"
	"strconv"
	"strings"
	"sync"

	"github.com/ThomsonReutersEikon/go-ntlm/ntlm"
	"github.com/git-lfs/git-lfs/config"
	"github.com/git-lfs/git-lfs/errors"
)

var (
	lfsMediaTypeRE  = regexp.MustCompile(`\Aapplication/vnd\.git\-lfs\+json(;|\z)`)
	jsonMediaTypeRE = regexp.MustCompile(`\Aapplication/json(;|\z)`)
)

type Client struct {
	Endpoints   EndpointFinder
	Credentials CredentialHelper
	SSH         SSHResolver
	Netrc       NetrcFinder

	DialTimeout         int
	KeepaliveTimeout    int
	TLSTimeout          int
	ConcurrentTransfers int
	SkipSSLVerify       bool

	Verbose          bool
	DebuggingVerbose bool
	VerboseOut       io.Writer

	hostClients map[string]*http.Client
	clientMu    sync.Mutex

	ntlmSessions map[string]ntlm.ClientSession
	ntlmMu       sync.Mutex

	httpLogger *syncLogger

	LoggingStats bool // DEPRECATED

	// only used for per-host ssl certs
	gitEnv Env
	osEnv  Env
	uc     *config.URLConfig
}

func NewClient(osEnv Env, gitEnv Env) (*Client, error) {
	if osEnv == nil {
		osEnv = make(TestEnv)
	}

	if gitEnv == nil {
		gitEnv = make(TestEnv)
	}

	netrc, netrcfile, err := ParseNetrc(osEnv)
	if err != nil {
		return nil, errors.Wrap(err, fmt.Sprintf("bad netrc file %s", netrcfile))
	}

	creds, err := getCredentialHelper(&config.Configuration{
		Os: osEnv, Git: gitEnv})
	if err != nil {
		return nil, errors.Wrap(err, "cannot find credential helper(s)")
	}

	var sshResolver SSHResolver = &sshAuthClient{os: osEnv}
	if gitEnv.Bool("lfs.cachecredentials", true) {
		sshResolver = withSSHCache(sshResolver)
	}

	c := &Client{
		Endpoints:           NewEndpointFinder(gitEnv),
		Credentials:         creds,
		SSH:                 sshResolver,
		Netrc:               netrc,
		DialTimeout:         gitEnv.Int("lfs.dialtimeout", 0),
		KeepaliveTimeout:    gitEnv.Int("lfs.keepalive", 0),
		TLSTimeout:          gitEnv.Int("lfs.tlstimeout", 0),
		ConcurrentTransfers: gitEnv.Int("lfs.concurrenttransfers", 3),
		SkipSSLVerify:       !gitEnv.Bool("http.sslverify", true) || osEnv.Bool("GIT_SSL_NO_VERIFY", false),
		Verbose:             osEnv.Bool("GIT_CURL_VERBOSE", false),
		DebuggingVerbose:    osEnv.Bool("LFS_DEBUG_HTTP", false),
		gitEnv:              gitEnv,
		osEnv:               osEnv,
		uc:                  config.NewURLConfig(gitEnv),
	}

	return c, nil
}

func (c *Client) GitEnv() Env {
	return c.gitEnv
}

func (c *Client) OSEnv() Env {
	return c.osEnv
}

func IsDecodeTypeError(err error) bool {
	_, ok := err.(*decodeTypeError)
	return ok
}

type decodeTypeError struct {
	Type string
}

func (e *decodeTypeError) TypeError() {}

func (e *decodeTypeError) Error() string {
	return fmt.Sprintf("Expected json type, got: %q", e.Type)
}

func DecodeJSON(res *http.Response, obj interface{}) error {
	ctype := res.Header.Get("Content-Type")
	if !(lfsMediaTypeRE.MatchString(ctype) || jsonMediaTypeRE.MatchString(ctype)) {
		return &decodeTypeError{Type: ctype}
	}

	err := json.NewDecoder(res.Body).Decode(obj)
	res.Body.Close()

	if err != nil {
		return errors.Wrapf(err, "Unable to parse HTTP response for %s %s", res.Request.Method, res.Request.URL)
	}

	return nil
}

// Env is an interface for the config.Environment methods that this package
// relies on.
type Env interface {
	Get(string) (string, bool)
	GetAll(string) []string
	Int(string, int) int
	Bool(string, bool) bool
	All() map[string][]string
}

type UniqTestEnv map[string]string

func (e UniqTestEnv) Get(key string) (v string, ok bool) {
	v, ok = e[key]
	return
}

func (e UniqTestEnv) GetAll(key string) []string {
	if v, ok := e.Get(key); ok {
		return []string{v}
	}
	return make([]string, 0)
}

func (e UniqTestEnv) Int(key string, def int) (val int) {
	s, _ := e.Get(key)
	if len(s) == 0 {
		return def
	}

	i, err := strconv.Atoi(s)
	if err != nil {
		return def
	}

	return i
}

func (e UniqTestEnv) Bool(key string, def bool) (val bool) {
	s, _ := e.Get(key)
	if len(s) == 0 {
		return def
	}

	switch strings.ToLower(s) {
	case "true", "1", "on", "yes", "t":
		return true
	case "false", "0", "off", "no", "f":
		return false
	default:
		return false
	}
}

func (e UniqTestEnv) All() map[string][]string {
	m := make(map[string][]string)
	for k, _ := range e {
		m[k] = e.GetAll(k)
	}
	return m
}

// TestEnv is a basic config.Environment implementation. Only used in tests, or
// as a zero value to NewClient().
type TestEnv map[string][]string

func (e TestEnv) Get(key string) (string, bool) {
	all := e.GetAll(key)

	if len(all) == 0 {
		return "", false
	}
	return all[len(all)-1], true
}

func (e TestEnv) GetAll(key string) []string {
	return e[key]
}

func (e TestEnv) Int(key string, def int) (val int) {
	s, _ := e.Get(key)
	if len(s) == 0 {
		return def
	}

	i, err := strconv.Atoi(s)
	if err != nil {
		return def
	}

	return i
}

func (e TestEnv) Bool(key string, def bool) (val bool) {
	s, _ := e.Get(key)
	if len(s) == 0 {
		return def
	}

	switch strings.ToLower(s) {
	case "true", "1", "on", "yes", "t":
		return true
	case "false", "0", "off", "no", "f":
		return false
	default:
		return false
	}
}

func (e TestEnv) All() map[string][]string {
	return e
}