package setup

import (
	"fmt"
	"net/url"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"
	"time"

	"github.com/mholt/caddy/middleware"
	"github.com/mholt/caddy/middleware/git"
	"github.com/mholt/caddy/middleware/git/webhook"
)

// Git configures a new Git service routine.
func Git(c *Controller) (middleware.Middleware, error) {
	repo, err := gitParse(c)
	if err != nil {
		return nil, err
	}

	// If a HookUrl is set, we switch to event based pulling.
	// Install the url handler
	if repo.HookUrl != "" {

		c.Startup = append(c.Startup, func() error {
			return repo.Pull()
		})

		webhook := &webhook.WebHook{Repo: repo}
		return func(next middleware.Handler) middleware.Handler {
			webhook.Next = next
			return webhook
		}, nil

	} else {
		c.Startup = append(c.Startup, func() error {

			// Start service routine in background
			git.Start(repo)

			// Do a pull right away to return error
			return repo.Pull()
		})
	}

	return nil, err
}

func gitParse(c *Controller) (*git.Repo, error) {
	repo := &git.Repo{Branch: "master", Interval: git.DefaultInterval, Path: c.Root}

	for c.Next() {
		args := c.RemainingArgs()

		switch len(args) {
		case 2:
			repo.Path = filepath.Clean(c.Root + string(filepath.Separator) + args[1])
			fallthrough
		case 1:
			repo.URL = args[0]
		}

		for c.NextBlock() {
			switch c.Val() {
			case "repo":
				if !c.NextArg() {
					return nil, c.ArgErr()
				}
				repo.URL = c.Val()
			case "path":
				if !c.NextArg() {
					return nil, c.ArgErr()
				}
				repo.Path = filepath.Clean(c.Root + string(filepath.Separator) + c.Val())
			case "branch":
				if !c.NextArg() {
					return nil, c.ArgErr()
				}
				repo.Branch = c.Val()
			case "key":
				if !c.NextArg() {
					return nil, c.ArgErr()
				}
				repo.KeyPath = c.Val()
			case "interval":
				if !c.NextArg() {
					return nil, c.ArgErr()
				}
				t, _ := strconv.Atoi(c.Val())
				if t > 0 {
					repo.Interval = time.Duration(t) * time.Second
				}
			case "hook":
				if !c.NextArg() {
					return nil, c.ArgErr()
				}
				repo.HookUrl = c.Val()

				// optional secret for validation
				if c.NextArg() {
					repo.HookSecret = c.Val()
				}

			case "then":
				thenArgs := c.RemainingArgs()
				if len(thenArgs) == 0 {
					return nil, c.ArgErr()
				}
				repo.Then = strings.Join(thenArgs, " ")
			default:
				return nil, c.ArgErr()
			}
		}
	}

	// if repo is not specified, return error
	if repo.URL == "" {
		return nil, c.ArgErr()
	}

	// if private key is not specified, convert repository URL to https
	// to avoid ssh authentication
	// else validate git URL
	// Note: private key support not yet available on Windows
	var err error
	if repo.KeyPath == "" {
		repo.URL, repo.Host, err = sanitizeHTTP(repo.URL)
	} else {
		repo.URL, repo.Host, err = sanitizeGit(repo.URL)
		// TODO add Windows support for private repos
		if runtime.GOOS == "windows" {
			return nil, fmt.Errorf("Private repository not yet supported on Windows")
		}
	}

	if err != nil {
		return nil, err
	}

	// validate git requirements
	if err = git.Init(); err != nil {
		return nil, err
	}

	return repo, repo.Prepare()
}

// sanitizeHTTP cleans up repository URL and converts to https format
// if currently in ssh format.
// Returns sanitized url, hostName (e.g. github.com, bitbucket.com)
// and possible error
func sanitizeHTTP(repoURL string) (string, string, error) {
	url, err := url.Parse(repoURL)
	if err != nil {
		return "", "", err
	}

	if url.Host == "" && strings.HasPrefix(url.Path, "git@") {
		url.Path = url.Path[len("git@"):]
		i := strings.Index(url.Path, ":")
		if i < 0 {
			return "", "", fmt.Errorf("Invalid git url %s", repoURL)
		}
		url.Host = url.Path[:i]
		url.Path = "/" + url.Path[i+1:]
	}

	repoURL = "https://" + url.Host + url.Path

	// add .git suffix if missing
	if !strings.HasSuffix(repoURL, ".git") {
		repoURL += ".git"
	}

	return repoURL, url.Host, nil
}

// sanitizeGit cleans up repository url and converts to ssh format for private
// repositories if required.
// Returns sanitized url, hostName (e.g. github.com, bitbucket.com)
// and possible error
func sanitizeGit(repoURL string) (string, string, error) {
	repoURL = strings.TrimSpace(repoURL)

	// check if valid ssh format
	if !strings.HasPrefix(repoURL, "git@") || strings.Index(repoURL, ":") < len("git@a:") {
		// check if valid http format and convert to ssh
		if url, err := url.Parse(repoURL); err == nil && strings.HasPrefix(url.Scheme, "http") {
			repoURL = fmt.Sprintf("git@%v:%v", url.Host, url.Path[1:])
		} else {
			return "", "", fmt.Errorf("Invalid git url %s", repoURL)
		}
	}
	hostURL := repoURL[len("git@"):]
	i := strings.Index(hostURL, ":")
	host := hostURL[:i]

	// add .git suffix if missing
	if !strings.HasSuffix(repoURL, ".git") {
		repoURL += ".git"
	}

	return repoURL, host, nil
}