gemini_service.go

package service

import (
	"context"
	"fmt"

	"github.com/google/generative-ai-go/genai"
	"github.com/spf13/viper"
	"google.golang.org/api/option"
)

type GeminiService struct{}

func NewGeminiService() *GeminiService {
	return &GeminiService{}
}

func (g *GeminiService) AnalyzeChanges(
	ctx context.Context,
	diff string,
) (string, error) {
	client, err := genai.NewClient(
		ctx,
		option.WithAPIKey(viper.GetString("api.key")),
	)
	if err != nil {
		fmt.Println("Error:", err)
		return "", err
	}
	defer client.Close()

	model := client.GenerativeModel("gemini-pro")
	resp, err := model.GenerateContent(
		ctx,
		genai.Text(
			fmt.Sprintf(
				`let's assume you're an automated AI that will generate a conventional git commit message based on this diff changes:
%s

The commit message must follow this format:
"<type>(<scope>): <description>

[optional body]

[optional footer(s)]"

Type must be one of the following:
- build: changes that affect the build system or external dependencies (example scopes: gulp, broccoli, npm)
- ci: changes to our CI configuration files and scripts (example scopes: Travis, Circle, BrowserStack, SauceLabs)
- docs: documentation only changes
- feat: a new feature
- fix: a bug fix
- perf: a code change that improves performance
- refactor: a code change that neither fixes a bug nor adds a feature
- style: changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc. Changes to web styling do not fall into this category )
- test: adding missing tests or correcting existing tests

Specification:
- Commits MUST be prefixed with a type, which consists of a noun, feat, fix, etc., followed by the OPTIONAL scope, OPTIONAL !, and REQUIRED terminal colon and space.
- A scope MAY be provided after a type. A scope MUST consist of a noun describing a section of the codebase surrounded by parenthesis, e.g., fix(parser):
- A description MUST immediately follow the colon and space after the type/scope prefix. The description is a short summary of the code changes, e.g., fix: array parsing issue when multiple spaces were contained in string.
- A description MUST started with lowercase.
- Descriptions CANNOT use past tense verbs.
- A longer commit body MAY be provided after the short description, providing additional contextual information about the code changes. The body MUST begin one blank line after the description.
- A commit body is free-form and MAY consist of any number of newline separated paragraphs.
- One or more footers MAY be provided one blank line after the body. Each footer MUST consist of a word token, followed by either a :<space> or <space># separator, followed by a string value (this is inspired by the git trailer convention).
- A footer’s token MUST use - in place of whitespace characters, e.g., Acked-by (this helps differentiate the footer section from a multi-paragraph body). An exception is made for BREAKING CHANGE, which MAY also be used as a token.
- A footer’s value MAY contain spaces and newlines, and parsing MUST terminate when the next valid footer token/separator pair is observed.
- Breaking changes MUST be indicated in the type/scope prefix of a commit, or as an entry in the footer.
- If included as a footer, a breaking change MUST consist of the uppercase text BREAKING CHANGE, followed by a colon, space, and description, e.g., BREAKING CHANGE: environment variables now take precedence over config files.
- If included in the type/scope prefix, breaking changes MUST be indicated by a ! immediately before the :. If ! is used, BREAKING CHANGE: MAY be omitted from the footer section, and the commit description SHALL be used to describe the breaking change.
- Types other than feat and fix MAY be used in your commit messages, e.g., docs: update ref docs.
- The units of information that make up Conventional Commits MUST NOT be treated as case sensitive by implementors, with the exception of BREAKING CHANGE which MUST be uppercase. 
- BREAKING-CHANGE MUST be synonymous with BREAKING CHANGE, when used as a token in a footer.

Exclude anything unnecessary, because your entire response will be passed directly into git commit`,
				diff,
			),
		),
	)
	if err != nil {
		fmt.Println("Error:", err)
		return "", nil
	}

	return fmt.Sprintf("%v", resp.Candidates[0].Content.Parts[0]), nil
}