package main

import (
	"bufio"
	"fmt"
	"slices"
	"strings"

	"src.opensuse.org/autogits/common"
	"src.opensuse.org/autogits/common/gitea-generated/models"
)

type PRReviewInfo struct {
	pr      *models.PullRequest
	reviews []*models.PullReview
}

func fetchPRandReviews(gitea GiteaPRInterface, org, repo string, prNum int64) (PRReviewInfo, error) {
	pr, reviews, err := gitea.GetPullRequestAndReviews(org, repo, prNum)
	if err != nil {
		return PRReviewInfo{}, err
	}

	return PRReviewInfo{
		pr:      pr,
		reviews: reviews,
	}, nil
}

func isMaintainerApprovedPR(pr PRReviewInfo, maintainers MaintainershipData) bool {
	m := slices.Concat(maintainers.ListPackageMaintainers(pr.pr.Base.Name), maintainers.ListProjectMaintainers())
	for _, review := range pr.reviews {
		if review.Stale {
			continue
		}

		if slices.Contains(m, review.User.UserName) {
			if review.State == common.ReviewStateApproved {
				return true
			}
			return false
		}
	}

	return true
}

func IsPrjGitPRApproved(gitea common.GiteaMaintainershipInterface, giteapr GiteaPRInterface, config common.AutogitConfig, prjGitPRNumber int64) (bool, error) {
	prjPR, _ := fetchPRandReviews(giteapr, config.Organization, config.GitProjectName, prjGitPRNumber)

	maintainers, _ := FetchProjectMaintainershipData(gitea, config.Organization, config.GitProjectName, config.Branch)

	_, prjAssociatedPRs := common.ExtractDescriptionAndPRs(bufio.NewScanner(strings.NewReader(prjPR.pr.Body)))

	for _, PR := range prjAssociatedPRs {
		prInfo, _ := fetchPRandReviews(giteapr, PR.Org, PR.Repo, PR.Num)

		_, associatedPRs := common.ExtractDescriptionAndPRs(bufio.NewScanner(strings.NewReader(prInfo.pr.Body)))

		if len(associatedPRs) != 1 {
			return false, fmt.Errorf("Associated PR doesn't link only to the prjgit PR: %s/%s#%d",
				associatedPRs[0].Org, associatedPRs[0].Repo, associatedPRs[0].Num)
		}

		if associatedPRs[0].Org != config.Organization || associatedPRs[0].Repo != config.GitProjectName || associatedPRs[0].Num != prjGitPRNumber {
			return false, fmt.Errorf("Associated PR (%s/%s#%d) not linking back to prj PR (%s/%s#%d)",
				associatedPRs[0].Org, associatedPRs[0].Repo, associatedPRs[0].Num,
				config.Organization, config.GitProjectName, prjGitPRNumber)
		}

		if !isMaintainerApprovedPR(prInfo, maintainers) {
			return false, nil
		}
	}

	requiredReviews := slices.Clone(config.Reviewers)
	for _, r := range prjPR.reviews {
		if !r.Stale && r.State == common.ReviewStateApproved && slices.Contains(requiredReviews, r.User.UserName) {
			idx := slices.Index(requiredReviews, r.User.UserName)
			requiredReviews = slices.Delete(requiredReviews, idx, idx+1)
		}
	}

	return len(requiredReviews) == 0, nil
}