// Package forgejo wraps the parts of the Gitea/Forgejo SDK that
// yaju-keisatsu needs: replying to comments and opening a correction PR.
package forgejo

import (
	"encoding/base64"
	"fmt"
	"strings"

	"code.gitea.io/sdk/gitea"
)

type Client struct {
	sdk *gitea.Client
}

func New(baseURL, token string) (*Client, error) {
	c, err := gitea.NewClient(baseURL, gitea.SetToken(token))
	if err != nil {
		return nil, fmt.Errorf("create gitea client: %w", err)
	}
	return &Client{sdk: c}, nil
}

// ReplyToIssue posts a comment on an issue or pull request.
func (c *Client) ReplyToIssue(owner, repo string, index int64, body string) error {
	_, _, err := c.sdk.CreateIssueComment(owner, repo, index, gitea.CreateIssueCommentOption{Body: body})
	if err != nil {
		return fmt.Errorf("create issue comment: %w", err)
	}
	return nil
}

// FileContent fetches a file's current text content and blob SHA at ref.
func (c *Client) FileContent(owner, repo, ref, path string) (content, sha string, err error) {
	meta, _, err := c.sdk.GetContents(owner, repo, ref, path)
	if err != nil {
		return "", "", fmt.Errorf("get file %s: %w", path, err)
	}
	if meta.Content == nil {
		return "", "", fmt.Errorf("get file %s: not a regular file", path)
	}
	// The API may line-wrap the base64 payload; strip whitespace before decoding.
	clean := strings.Map(func(r rune) rune {
		if r == '\n' || r == '\r' {
			return -1
		}
		return r
	}, *meta.Content)
	decoded, err := base64.StdEncoding.DecodeString(clean)
	if err != nil {
		return "", "", fmt.Errorf("decode file %s: %w", path, err)
	}
	return string(decoded), meta.SHA, nil
}

// CommitCorrection commits newContent for path on a new branch (branched off
// baseBranch) without touching baseBranch itself.
func (c *Client) CommitCorrection(owner, repo, baseBranch, newBranch, path, sha, newContent, message string) error {
	_, _, err := c.sdk.UpdateFile(owner, repo, path, gitea.UpdateFileOptions{
		SHA:     sha,
		Content: base64.StdEncoding.EncodeToString([]byte(newContent)),
		FileOptions: gitea.FileOptions{
			Message:       message,
			BranchName:    baseBranch,
			NewBranchName: newBranch,
		},
	})
	if err != nil {
		return fmt.Errorf("update file %s: %w", path, err)
	}
	return nil
}

// OpenCorrectionPR opens a pull request from head into base.
func (c *Client) OpenCorrectionPR(owner, repo, head, base, title, body string) error {
	_, _, err := c.sdk.CreatePullRequest(owner, repo, gitea.CreatePullRequestOption{
		Head:  head,
		Base:  base,
		Title: title,
		Body:  body,
	})
	if err != nil {
		return fmt.Errorf("create pull request: %w", err)
	}
	return nil
}