package main

import (
	"bytes"
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"

	"gopkg.in/ini.v1"
)

// GetConfig fetch configuration
func GetConfig(config *Config) {
	var configfile string

	var globalconfig GlobalConfig
	var githubconfig GitHubConfig
	var gogsconfig GogsConfig

	flag.Usage = Usage
	flag.StringVar(&configfile, "configfile", "github-to-gogs.ini", "config file to use with github-to-gogs section")
	flag.Parse()

	cfg, err := ini.Load(configfile)
	HandleFatalError(err)

	globalsection := cfg.Section("global")
	githubsection := cfg.Section("github")
	gogssection := cfg.Section("gogs")

	globalconfig.UserAgent = globalsection.Key("user_agent").String()
	globalconfig.RequestTimeout, err = globalsection.Key("request_timeout").Duration()
	HandleError(err)

	githubconfig.StarsPages = githubsection.Key("stars_pages").String()
	githubconfig.MaxPagesNumber, err = githubsection.Key("max_pages_number").Int()
	HandleError(err)

	githubconfig.AuthUsername = githubsection.Key("auth_username").String()
	githubconfig.AuthPassword = githubsection.Key("auth_password").String()
	githubconfig.ContentType = githubsection.Key("content_type").String()

	gogsconfig.UID = -1
	gogsconfig.Username = gogssection.Key("username").String()
	gogsconfig.DestUsername = gogssection.Key("dest_username").String()
	gogsconfig.RepoURLTmpl = gogssection.Key("repo_url_tmpl").String()
	gogsconfig.OrgsURLTmpl = gogssection.Key("orgs_url_tmpl").String()
	gogsconfig.MigrateURL = gogssection.Key("migrate_url").String()
	gogsconfig.AuthToken = gogssection.Key("auth_token").String()
	gogsconfig.ContentType = gogssection.Key("content_type").String()
	gogsconfig.Mirror, err = gogssection.Key("mirror").Bool()
	HandleError(err)

	*config = Config{globalconfig: globalconfig,
		githubconfig: githubconfig,
		gogsconfig:   gogsconfig}
}

// GetReposFromGitHub get starred repositories from github
func GetReposFromGitHub(config *Config) []GitHubRepo {
	var repolist []GitHubRepo
	var repo []GitHubRepo

	for num := 1; num <= config.githubconfig.MaxPagesNumber; num++ {
		url := fmt.Sprintf(config.githubconfig.StarsPages, config.githubconfig.AuthUsername, num)

		resp := InvokeGitHub(config, url)

		err := json.Unmarshal(*GetResponseBody(resp), &repo)
		HandleError(err)

		for _, elem := range repo {
			repolist = append(repolist, elem)
		}
	}
	fmt.Println("Repositories from Github fetched !")
	return repolist
}

// InvokeGitHub ...
func InvokeGitHub(config *Config, url string) *http.Response {
	req, err := http.NewRequest("GET", url, nil)
	HandleError(err)

	req.Header.Add("Content-Type", config.githubconfig.ContentType)
	req.Header.Set("User-Agent", config.globalconfig.UserAgent)
	req.SetBasicAuth(config.githubconfig.AuthUsername, config.githubconfig.AuthPassword)

	client := &http.Client{}
	resp, err := client.Do(req)
	HandleError(err)

	return resp
}

// GetResponseBody converts http responses bodies as bytes slice
func GetResponseBody(resp *http.Response) *[]byte {
	bodyBytes, err := ioutil.ReadAll(resp.Body)
	HandleError(err)
	return &bodyBytes
}

// CheckGogsExistingRepo checks if there's an existing repository in gogs
func CheckGogsExistingRepo(config *Config, repo GitHubRepo) bool {
	var isExists bool

	gogsrepourl := fmt.Sprintf(config.gogsconfig.RepoURLTmpl, config.gogsconfig.DestUsername, repo.Name)

	req, err := http.NewRequest("GET", gogsrepourl, nil)
	req.Header.Set("Authorization", config.gogsconfig.AuthToken)
	req.Header.Set("User-Agent", config.globalconfig.UserAgent)

	client := &http.Client{}
	resp, err := client.Do(req)
	HandleError(err)

	if resp.StatusCode == 200 {
		isExists = true
	} else {
		isExists = false
	}

	return isExists
}

// GetGogsUserUID get the logued user identifier
func GetGogsUserUID(config *Config) {
	var gogsorg GogsOrg

	gogsrepourl := fmt.Sprintf(config.gogsconfig.OrgsURLTmpl, config.gogsconfig.DestUsername)

	req, err := http.NewRequest("GET", gogsrepourl, nil)
	req.Header.Set("Authorization", config.gogsconfig.AuthToken)
	req.Header.Set("User-Agent", config.globalconfig.UserAgent)

	client := &http.Client{}
	resp, err := client.Do(req)
	HandleError(err)

	err = json.Unmarshal(*GetResponseBody(resp), &gogsorg)
	HandleError(err)

	config.gogsconfig.UID = gogsorg.ID
}

// MigrateReposToGogs migrates input repositories to gogs
func MigrateReposToGogs(config *Config, repolist []GitHubRepo) {
	fmt.Println("Migrate repos to Gogs...")

	client := &http.Client{}

	for _, elem := range repolist {
		if !CheckGogsExistingRepo(config, elem) {
			jsondata := fmt.Sprintf(`{"uid" : %d, "repo_name" : "%s" , "mirror" : %v, "clone_addr" : "%s"}`, config.gogsconfig.UID, elem.Name, true, elem.CloneURL)
			fmt.Println(fmt.Sprintf("Migrating repo %s to gogs rest api", elem.Name))

			req, err := http.NewRequest("POST", config.gogsconfig.MigrateURL, bytes.NewBufferString(jsondata))
			HandleError(err)

			req.Header.Add("Content-Type", config.gogsconfig.ContentType)
			req.Header.Set("User-Agent", config.globalconfig.UserAgent)
			req.Header.Set("Authorization", config.gogsconfig.AuthToken)

			client.Timeout = config.globalconfig.RequestTimeout

			_, err = client.Do(req)
			HandleFatalError(err)
		} else {
			fmt.Println(fmt.Sprintf("Not migrating, %s exists in gogs", elem.Name))
		}
	}
}

// HandleError handles errors to return err
func HandleError(err error) {
	if err != nil {
		log.Println(err)
	}
}

// HandleFatalError fatal errors
func HandleFatalError(err error) {
	if err != nil {
		log.Fatal(err)
		os.Exit(2)
	}
}

// Usage displays possible arguments
func Usage() {
	flag.PrintDefaults()
	os.Exit(1)
}