package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/exec"
	"strings"
	"syscall"

	"github.com/gogs/git-module"
)

const sites_dir = "./sites"

type DeployError struct {
	code int
	where string
	details string
	command_output string
}
func newDeployError(code int, where string, details string, command_output string) DeployError {
	return DeployError{ code: code, where: where, details: details }
}

// fileExists returns whether the given file or directory exists.
func fileExists(path string) (bool, error) {
    _, err := os.Stat(path)
    if err == nil { return true, nil }
    if os.IsNotExist(err) { return false, nil }
    return false, err
}

// startServer attempts to start a Lapis server in the given repository.
func restartServer(name string) DeployError {
	log.Printf("Restarting Lapis server on repository %s...", name)

	old_cwd, _ := os.Getwd()
	defer syscall.Chdir(old_cwd)
	syscall.Chdir(sites_dir+"/"+name)

	out, err := exec.Command("lapis", "build").CombinedOutput()
	if err != nil {
		return newDeployError(1, "restartServer", fmt.Sprintf("Failed to run 'lapis build' in repository '%s'", name), string(out))
	}
	log.Printf("[lapis build] %s", out)
	if !strings.Contains(string(out), "HUP") {
		return newDeployError(1, "restartServer", "'lapis build' command returned unexpected value!", string(out))
	}
	return DeployError{}
}

// pullRepo attempts to pull or clone a repository using the given name and url
func pullRepo(url string, name string) DeployError  {	
	exists, err := fileExists(sites_dir+"/"+name)
	if err != nil {
		return newDeployError(1, "fileExists",
			fmt.Sprintf("Failed to check whether folder '%s' exists while pulling down repository '%s'!", name, name), "")
	}
	if !exists {
		log.Printf("Cloning repository %s...", name)
		if err = git.Clone(url, sites_dir+"/"+name); err != nil {
			return newDeployError(1, "pullRepo", fmt.Sprintf("Failed to pull down repository '%s'", name), "")
		}
	} else {
		log.Printf("Pulling down repository %s...", name)
		repo,err := git.Open(sites_dir+"/"+name)
		if err != nil {
			return newDeployError(1, "pullRepo", fmt.Sprintf("Failed to open git repository '%s'", name), "")
		}
		repo.Pull()
	}
	return DeployError{}
}

func handler(data map[string]interface{}) {
	repository := data["repository"].(map[string]interface{})
	log.Default().Printf("Repo: %s", repository["full_name"])

	deploy_error := pullRepo(repository["ssh_url"].(string), repository["name"].(string))
	if deploy_error.code != 0 {
		log.Default().Printf("Error in %s! [Code: %d] (%s)", deploy_error.where, deploy_error.code, deploy_error.details)
	}
	deploy_error = restartServer(repository["name"].(string))
	if deploy_error.code != 0 {
		log.Printf("Error in %s! [Code: %d] (%s) {Command output: '%s'}",
			deploy_error.where, deploy_error.code, deploy_error.details, deploy_error.command_output)
	}	
}

func main()  {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request){
		var data map[string]interface{}
		err := json.NewDecoder(r.Body).Decode(&data)
		if err != nil {
			log.Panic(err)
			return
		}

		go handler(data)
		fmt.Fprint(w, "Received!")
	})
	log.Fatal(http.ListenAndServe(":7575", nil))
}