package github

import (
	"context"
	"encoding/base64"
	"log/slog"
	"net/http"
	"strconv"

	"forge.cadoles.com/wpetit/clearcase/internal/core/model"
	"forge.cadoles.com/wpetit/clearcase/internal/core/port"
	"forge.cadoles.com/wpetit/clearcase/internal/core/service"
	"github.com/google/go-github/v69/github"
	"github.com/pkg/errors"
)

type Forge struct {
	client *github.Client
}

// CreateIssue implements port.Forge.
func (f *Forge) CreateIssue(ctx context.Context, projectID string, title string, body string) (string, error) {
	repo, err := f.getRepository(ctx, projectID)
	if err != nil {
		return "", errors.WithStack(err)
	}

	issue, res, err := f.client.Issues.Create(ctx, *repo.Owner.Login, *repo.Name, &github.IssueRequest{
		Title: &title,
		Body:  &body,
	})
	if res.StatusCode == http.StatusForbidden || res.StatusCode == http.StatusUnauthorized {
		slog.ErrorContext(ctx, "could not create issue", slog.Any("error", errors.WithStack(err)))
		return "", errors.WithStack(service.ErrForgeNotAvailable)
	}

	return *issue.HTMLURL, nil
}

// GetAllProjects implements port.Forge.
func (f *Forge) GetAllProjects(ctx context.Context) ([]*model.Project, error) {
	projects := make([]*model.Project, 0)

	page := 1
	for {
		repos, res, err := f.client.Repositories.ListByAuthenticatedUser(ctx, &github.RepositoryListByAuthenticatedUserOptions{
			Type: "all",
			ListOptions: github.ListOptions{
				Page:    page,
				PerPage: 100,
			},
		})
		if err != nil {
			if res.StatusCode == http.StatusForbidden || res.StatusCode == http.StatusUnauthorized {
				slog.ErrorContext(ctx, "could not retrieve user repositories", slog.Any("error", errors.WithStack(err)))
				return nil, errors.WithStack(service.ErrForgeNotAvailable)
			}

			return nil, errors.WithStack(err)
		}

		for _, r := range repos {
			if r.ID == nil || r.FullName == nil {
				continue
			}

			var projectDescription string
			if r.Description != nil {
				projectDescription = *r.Description
			}

			projects = append(projects, &model.Project{
				ID:          strconv.FormatInt(*r.ID, 10),
				Name:        *r.FullName,
				Description: projectDescription,
			})

		}

		if res.NextPage == 0 {
			return projects, nil
		}

		page = res.NextPage
	}
}

// GetFile implements port.Forge.
func (f *Forge) GetFile(ctx context.Context, rawProjectID string, path string) ([]byte, error) {
	repo, err := f.getRepository(ctx, rawProjectID)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	fileContent, _, res, err := f.client.Repositories.GetContents(ctx, *repo.Owner.Login, *repo.Name, path, nil)
	if err != nil {
		if res.StatusCode == http.StatusForbidden || res.StatusCode == http.StatusUnauthorized {
			slog.ErrorContext(ctx, "could not retrieve file content", slog.Any("error", errors.WithStack(err)))
			return nil, errors.WithStack(service.ErrForgeNotAvailable)
		}

		if res.StatusCode == http.StatusNotFound {
			return nil, errors.WithStack(port.ErrFileNotFound)
		}

		return nil, errors.WithStack(err)
	}

	decoded, err := base64.StdEncoding.DecodeString(*fileContent.Content)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return decoded, nil
}

// GetIssueTemplate implements port.Forge.
func (f *Forge) GetIssueTemplate(ctx context.Context, projectID string) (string, error) {
	data, err := f.GetFile(ctx, projectID, ".github/ISSUE_TEMPLATE/bug_report.md")
	if err != nil {
		return "", errors.WithStack(err)
	}

	return string(data), nil
}

// GetIssues implements port.Forge.
func (f *Forge) GetIssues(ctx context.Context, projectID string, issueIDs ...string) ([]*model.Issue, error) {
	repo, err := f.getRepository(ctx, projectID)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	issues := make([]*model.Issue, 0)
	for _, rawIssueID := range issueIDs {
		issueID, err := strconv.ParseInt(rawIssueID, 10, 64)
		if err != nil {
			slog.ErrorContext(ctx, "could not parse issue id", slog.Any("error", errors.WithStack(err)))
			issues = append(issues, nil)
			continue
		}

		issue, _, err := f.client.Issues.Get(ctx, *repo.Owner.Login, *repo.Name, int(issueID))
		if err != nil {
			slog.ErrorContext(ctx, "could not parse retrieve issue", slog.Int("issueID", int(issueID)), slog.String("repository", *repo.FullName), slog.Any("error", errors.WithStack(err)))
			issues = append(issues, nil)
			continue
		}

		issues = append(issues, &model.Issue{
			ID:    strconv.FormatInt(*issue.ID, 10),
			Title: *issue.Title,
			Body:  *issue.Body,
		})
	}

	return issues, nil
}

// GetProject implements port.Forge.
func (f *Forge) GetProject(ctx context.Context, rawProjectID string) (*model.Project, error) {
	repo, err := f.getRepository(ctx, rawProjectID)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	var projectDescription string
	if repo.Description != nil {
		projectDescription = *repo.Description
	}

	return &model.Project{
		ID:          strconv.FormatInt(*repo.ID, 10),
		Name:        *repo.Name,
		Description: projectDescription,
	}, nil
}

// GetProjectLanguages implements port.Forge.
func (f *Forge) GetProjectLanguages(ctx context.Context, rawProjectID string) ([]string, error) {
	repo, err := f.getRepository(ctx, rawProjectID)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	mappedLanguages, res, err := f.client.Repositories.ListLanguages(ctx, *repo.Owner.Login, *repo.Name)
	if err != nil {
		if res.StatusCode == http.StatusForbidden || res.StatusCode == http.StatusUnauthorized {
			slog.ErrorContext(ctx, "could not retrieve repository languages", slog.Any("error", errors.WithStack(err)))
			return nil, errors.WithStack(service.ErrForgeNotAvailable)
		}

		return nil, errors.WithStack(err)
	}

	languages := make([]string, 0, len(mappedLanguages))

	for l := range mappedLanguages {
		languages = append(languages, l)
	}

	return languages, nil
}

func (f *Forge) getRepository(ctx context.Context, rawProjectID string) (*github.Repository, error) {
	projectID, err := strconv.ParseInt(rawProjectID, 10, 64)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	repo, res, err := f.client.Repositories.GetByID(ctx, projectID)
	if err != nil {
		if res.StatusCode == http.StatusForbidden || res.StatusCode == http.StatusUnauthorized {
			slog.ErrorContext(ctx, "could not retrieve repository", slog.Any("error", errors.WithStack(err)))
			return nil, errors.WithStack(service.ErrForgeNotAvailable)
		}

		return nil, errors.WithStack(err)
	}

	return repo, nil
}

func NewForge(client *github.Client) *Forge {
	return &Forge{client: client}
}

var _ port.Forge = &Forge{}