main.go

package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"net/url"
	"os"
	"strings"
	"time"

	"github.com/google/go-github/v60/github"
)

// https://goreleaser.com/cookbooks/using-main.version/
var (
	version = "unset"
	commit  = "none"
	date    = "unknown"
)

type Options struct {
	// from flag
	from                      string
	to                        string
	labels                    []string
	template                  *string
	json                      bool
	disableGeneratedByMessage bool
	customParameters          any

	// from env
	owner       string
	repo        string
	gitHubToken string
	apiUrl      *url.URL
}

func getOptions() (Options, error) {
	from := flag.String("from", "", "The base branch name.")
	to := flag.String("to", "", "The target branch name.")
	labelsFlag := flag.String("labels", "", "Specify the labels to add to the pull request as a comma-separated list of strings.")
	template := flag.String("template", "", "The path to the template file.")
	enableJsonOutput := flag.Bool("json", false, "Output the release pull request data in JSON format.")
	disableGeneratedByMessage := flag.Bool("disable-generated-by-message", false, "Disable the generated by message in the release pull request body.")
	customParametersString := flag.String("custom-parameters", "{}", "Passed to the template as an object.")
	flag.Parse()

	githubToken := os.Getenv("GITHUB_TOKEN")
	repository := strings.Split(os.Getenv("GITHUB_REPOSITORY"), "/")
	owner := repository[0]
	repo := repository[1]
	rawApiUrl := os.Getenv("GITHUB_API_URL")

	apiUrl, _ := url.Parse(rawApiUrl)

	var labels []string
	if *labelsFlag != "" {
		labels = strings.Split(*labelsFlag, ",")
	}

	var customParameters any
	err := json.Unmarshal([]byte(*customParametersString), &customParameters)
	if err != nil {
		return Options{}, err
	}

	return Options{
		from:                      *from,
		to:                        *to,
		labels:                    labels,
		template:                  template,
		json:                      *enableJsonOutput,
		disableGeneratedByMessage: *disableGeneratedByMessage,
		customParameters:          customParameters,
		owner:                     owner,
		repo:                      repo,
		gitHubToken:               githubToken,
		apiUrl:                    apiUrl,
	}, nil
}

type Result struct {
	IsCreated          bool                `json:"is_created,omitempty"`
	ReleasePullRequest *github.PullRequest `json:"release_pull_request,omitempty"`
}

func getResultJson(result Result) (string, error) {
	resultJson, err := json.Marshal(result)
	if err != nil {
		return "", err
	}
	return string(resultJson), nil
}

func exitWithError(err error) {
	fmt.Fprintln(os.Stderr, "Error: ", err)
	os.Exit(1)
}

func run(options Options) (*Result, error) {
	logger = GetLogger()
	logger.Printf("version: %s, commit: %s, date: %s\n", version, commit, date)

	ctx := context.Background()

	from := options.from
	to := options.to

	client := NewClient(GithubClientOptions{owner: options.owner, repo: options.repo, githubToken: options.gitHubToken, apiUrl: options.apiUrl})

	totalCommits, pullRequests, commits, err := client.FetchChanges(ctx, from, to)
	if err != nil {
		return nil, err
	}

	if totalCommits == 0 {
		logger.Println("No pull requests or commits were found for the release. Nothing to do.")
		return nil, nil
	}

	logger.Println("Found pull requests: ", len(pullRequests))
	logger.Println("Found commits: ", len(commits))

	currentTime := time.Now()
	date := currentTime.Format("2006-01-02")
	renderTemplateData := RenderTemplateData{
		PullRequests:     pullRequests,
		Commits:          commits,
		Date:             date,
		From:             from,
		To:               to,
		CustomParameters: options.customParameters,
	}
	data, err := RenderTemplate(options.template, renderTemplateData, options.disableGeneratedByMessage)

	if err != nil {
		return nil, err
	}

	parts := strings.SplitN(data, "\n", 2)
	title := parts[0]
	body := parts[1]

	logger.Println("Title of pull request:  ", title)

	pr, created, err := client.CreatePullRequest(ctx, title, body, from, to)
	if err != nil {
		return nil, err
	}

	if created {
		logger.Println("Created new a pull request.", pr.GetNumber())
	} else {
		_, err := client.UpdatePullRequest(ctx, pr.GetNumber(), title, body)
		if err != nil {
			return nil, err
		}
		logger.Println("The pull request already exists. The body was updated.", pr.GetNumber())
	}

	if len(options.labels) > 0 {
		err := client.AddLabelsToPullRequest(ctx, pr.GetNumber(), options.labels)
		if err != nil {
			return nil, err
		}
		logger.Println("Added labels to the pull request.", pr.GetNumber())
	}

	result := Result{IsCreated: created, ReleasePullRequest: pr}

	return &result, nil
}

func main() {
	options, err := getOptions()

	if err != nil {
		exitWithError(err)
	}

	result, err := run(options)

	if err != nil {
		exitWithError(err)
	}

	if options.json {

		if result == nil {
			result = &Result{}
		}

		resultJson, err := getResultJson(*result)

		if err != nil {
			exitWithError(err)
		}

		fmt.Println(resultJson)
	}
}