package main

import (
	"context"
	"flag"
	"fmt"
	"log/slog"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"gitea.weiker.me/rodin/review-bot/budget"
	"gitea.weiker.me/rodin/review-bot/gitea"
	"gitea.weiker.me/rodin/review-bot/llm"
	"gitea.weiker.me/rodin/review-bot/review"
)

var version = "dev"

// setupLogger configures the global slog default logger based on format and verbosity.
func setupLogger(format, verbosity string) {
	var level slog.Level
	switch strings.ToLower(verbosity) {
	case "debug":
		level = slog.LevelDebug
	case "info":
		level = slog.LevelInfo
	case "warn":
		level = slog.LevelWarn
	case "error":
		level = slog.LevelError
	default:
		level = slog.LevelInfo
	}

	opts := &slog.HandlerOptions{Level: level}

	var handler slog.Handler
	switch strings.ToLower(format) {
	case "json":
		handler = slog.NewJSONHandler(os.Stderr, opts)
	default:
		handler = slog.NewTextHandler(os.Stderr, opts)
	}

	slog.SetDefault(slog.New(handler))
}

func main() {
	versionFlag := flag.Bool("version", false, "Print version and exit")
	// Logging flags
	logFormat := flag.String("log-format", envOrDefault("LOG_FORMAT", "text"), "Log output format: text or json")
	verbosity := flag.String("verbosity", envOrDefault("LOG_VERBOSITY", "info"), "Log verbosity: debug, info, warn, error")
	// CLI flags
	giteaURL := flag.String("gitea-url", envOrDefault("GITEA_URL", ""), "Gitea instance URL")
	repo := flag.String("repo", envOrDefault("GITEA_REPO", ""), "Repository (owner/name)")
	prNum := flag.String("pr", envOrDefault("PR_NUMBER", ""), "Pull request number")
	reviewerName := flag.String("reviewer-name", envOrDefault("REVIEWER_NAME", ""), "Reviewer display name")
	reviewerToken := flag.String("reviewer-token", envOrDefault("REVIEWER_TOKEN", ""), "Gitea token for posting review")
	llmBaseURL := flag.String("llm-base-url", envOrDefault("LLM_BASE_URL", ""), "LLM API base URL")
	llmAPIKey := flag.String("llm-api-key", envOrDefault("LLM_API_KEY", ""), "LLM API key")
	llmModel := flag.String("llm-model", envOrDefault("LLM_MODEL", ""), "LLM model name")
	conventionsFile := flag.String("conventions-file", envOrDefault("CONVENTIONS_FILE", ""), "Conventions file path in repo (e.g. CLAUDE.md)")
	systemPromptFile := flag.String("system-prompt-file", envOrDefault("SYSTEM_PROMPT_FILE", ""), "Local file with additional system prompt instructions")
	patternsRepo := flag.String("patterns-repo", envOrDefault("PATTERNS_REPO", ""), "Repo with language patterns (e.g. rodin/elixir-patterns)")
	patternsFiles := flag.String("patterns-files", envOrDefault("PATTERNS_FILES", "README.md"), "Comma-separated file paths to fetch from patterns repo")
	dryRun := flag.Bool("dry-run", false, "Print review to stdout instead of posting")
	llmTemp := flag.Float64("llm-temperature", envOrDefaultFloat("LLM_TEMPERATURE", 0), "LLM temperature (0 = server default)")
	llmTimeout := flag.Int("llm-timeout", envOrDefaultInt("LLM_TIMEOUT", 300), "LLM request timeout in seconds (default 300)")
	llmProvider := flag.String("llm-provider", envOrDefault("LLM_PROVIDER", "openai"), "LLM API provider: openai, anthropic, or aicore")
	// AI Core specific flags (only used when provider=aicore)
	aicoreClientID := flag.String("aicore-client-id", envOrDefault("AICORE_CLIENT_ID", ""), "SAP AI Core client ID (for provider=aicore)")
	aicoreClientSecret := flag.String("aicore-client-secret", envOrDefault("AICORE_CLIENT_SECRET", ""), "SAP AI Core client secret (for provider=aicore)")
	aicoreAuthURL := flag.String("aicore-auth-url", envOrDefault("AICORE_AUTH_URL", ""), "SAP AI Core auth URL (for provider=aicore)")
	aicoreAPIURL := flag.String("aicore-api-url", envOrDefault("AICORE_API_URL", ""), "SAP AI Core API URL (for provider=aicore)")
	aicoreResourceGroup := flag.String("aicore-resource-group", envOrDefault("AICORE_RESOURCE_GROUP", "default"), "SAP AI Core resource group (for provider=aicore)")

	flag.Parse()

	if *versionFlag {
		fmt.Printf("review-bot %s\n", version)
		os.Exit(0)
	}

	// Initialize structured logger
	setupLogger(*logFormat, *verbosity)

	slog.Info("review-bot starting", "version", version)

	// Validate required fields
	// For aicore provider, llm-base-url and llm-api-key are not required
	isAICore := llm.Provider(*llmProvider) == llm.ProviderAICore
	if *giteaURL == "" || *repo == "" || *prNum == "" || *reviewerToken == "" || *llmModel == "" {
		fmt.Fprintf(os.Stderr, "Error: missing required flags or environment variables\n\n")
		fmt.Fprintf(os.Stderr, "Required: --gitea-url, --repo, --pr, --reviewer-token, --llm-model\n")
		os.Exit(1)
	}
	if !isAICore && (*llmBaseURL == "" || *llmAPIKey == "") {
		fmt.Fprintf(os.Stderr, "Error: --llm-base-url and --llm-api-key are required for provider=%s\n", *llmProvider)
		os.Exit(1)
	}
	if isAICore && (*aicoreClientID == "" || *aicoreClientSecret == "" || *aicoreAuthURL == "" || *aicoreAPIURL == "") {
		fmt.Fprintf(os.Stderr, "Error: AI Core credentials required for provider=aicore\n\n")
		fmt.Fprintf(os.Stderr, "Required: --aicore-client-id, --aicore-client-secret, --aicore-auth-url, --aicore-api-url\n")
		os.Exit(1)
	}

	// Validate reviewer-name: only safe characters allowed in sentinel
	if err := validateReviewerName(*reviewerName); err != nil {
		slog.Error("invalid reviewer name", "error", err)
		os.Exit(1)
	}

	// Parse repo owner/name
	parts := strings.SplitN(*repo, "/", 2)
	if len(parts) != 2 {
		slog.Error("invalid repo format", "repo", *repo, "expected", "owner/name")
		os.Exit(1)
	}
	owner, repoName := parts[0], parts[1]

	// Parse PR number
	prNumber, err := strconv.Atoi(*prNum)
	if err != nil {
		slog.Error("invalid PR number", "pr", *prNum, "error", err)
		os.Exit(1)
	}

	// Initialize clients
	giteaClient := gitea.NewClient(*giteaURL, *reviewerToken)
	llmClient := llm.NewClient(*llmBaseURL, *llmAPIKey, *llmModel)
	if *llmTemp < 0 || *llmTemp > 2 {
		slog.Error("invalid LLM temperature", "temperature", *llmTemp, "range", "0-2")
		os.Exit(1)
	}
	if *llmTemp > 0 {
		llmClient.WithTemperature(*llmTemp)
	}
	switch llm.Provider(*llmProvider) {
	case llm.ProviderOpenAI, llm.ProviderAnthropic:
		llmClient.WithProvider(llm.Provider(*llmProvider))
	case llm.ProviderAICore:
		llmClient.WithAICore(llm.AICoreConfig{
			ClientID:      *aicoreClientID,
			ClientSecret:  *aicoreClientSecret,
			AuthURL:       *aicoreAuthURL,
			APIURL:        *aicoreAPIURL,
			ResourceGroup: *aicoreResourceGroup,
		})
		slog.Info("using SAP AI Core provider", "resource_group", *aicoreResourceGroup)
	default:
		slog.Error("invalid LLM provider", "provider", *llmProvider, "valid", "openai, anthropic, aicore")
		os.Exit(1)
	}
	if *llmTimeout > 0 {
		llmClient.WithTimeout(time.Duration(*llmTimeout) * time.Second)
	}

	// Create a top-level context. Timeout derived from LLM timeout + 1 min for other ops.
	overallTimeout := time.Duration(*llmTimeout)*time.Second + time.Minute
	ctx, cancel := context.WithTimeout(context.Background(), overallTimeout)
	defer cancel()

	slog.Info("reviewing pull request", "pr", prNumber, "repo", fmt.Sprintf("%s/%s", owner, repoName))

	// Step 1: Fetch PR metadata
	pr, err := giteaClient.GetPullRequest(ctx, owner, repoName, prNumber)
	if err != nil {
		slog.Error("failed to fetch PR", "pr", prNumber, "error", err)
		os.Exit(1)
	}
	slog.Info("fetched PR metadata", "pr", prNumber, "title", pr.Title)

	// Step 2: Fetch diff
	diff, err := giteaClient.GetPullRequestDiff(ctx, owner, repoName, prNumber)
	if err != nil {
		slog.Error("failed to fetch diff", "pr", prNumber, "error", err)
		os.Exit(1)
	}
	slog.Info("fetched diff", "bytes", len(diff))

	// Step 3: Fetch full file content for modified files
	fileContext := ""
	files, err := giteaClient.GetPullRequestFiles(ctx, owner, repoName, prNumber)
	if err != nil {
		slog.Warn("could not fetch PR files list", "pr", prNumber, "error", err)
	} else {
		fileContext = fetchFileContext(ctx, giteaClient, owner, repoName, pr.Head.Ref, files)
		slog.Debug("fetched file context", "files", len(files))
	}

	// Step 4: Check CI status
	ciPassed := true
	ciDetails := ""
	if pr.Head.Sha != "" {
		statuses, err := giteaClient.GetCommitStatuses(ctx, owner, repoName, pr.Head.Sha)
		if err != nil {
			slog.Warn("could not fetch CI status", "sha", pr.Head.Sha, "error", err)
		} else {
			ciPassed, ciDetails = evaluateCIStatus(statuses)
			slog.Info("CI status checked", "passed", ciPassed)
		}
	}

	// Step 5: Load conventions file if specified
	conventions := ""
	if *conventionsFile != "" {
		content, err := giteaClient.GetFileContent(ctx, owner, repoName, *conventionsFile)
		if err != nil {
			slog.Warn("could not load conventions file", "file", *conventionsFile, "error", err)
		} else {
			conventions = content
			slog.Debug("loaded conventions file", "file", *conventionsFile, "bytes", len(conventions))
		}
	}

	// Step 6: Load patterns from external repo if specified
	patterns := ""
	if *patternsRepo != "" {
		patterns = fetchPatterns(ctx, giteaClient, *patternsRepo, *patternsFiles)
		slog.Debug("loaded patterns", "repo", *patternsRepo, "bytes", len(patterns))
	}

	// Step 6b: Load additional system prompt if specified
	additionalPrompt := ""
	if *systemPromptFile != "" {
		workspace := os.Getenv("GITHUB_WORKSPACE")
		if workspace == "" {
			workspace, _ = os.Getwd()
		}
		absWorkspace, err := filepath.Abs(workspace)
		if err != nil {
			slog.Error("failed to resolve workspace path", "error", err)
			os.Exit(1)
		}
		promptPath := filepath.Join(absWorkspace, *systemPromptFile)
		promptPath = filepath.Clean(promptPath)
		if !strings.HasPrefix(promptPath, absWorkspace+string(filepath.Separator)) && promptPath != absWorkspace {
			slog.Error("system-prompt-file resolves outside workspace", "path", promptPath, "workspace", absWorkspace)
			os.Exit(1)
		}
		// Resolve symlinks and re-validate to prevent symlink traversal
		resolvedPath, err := filepath.EvalSymlinks(promptPath)
		if err != nil {
			slog.Error("failed to resolve system prompt file", "path", promptPath, "error", err)
			os.Exit(1)
		}
		if !strings.HasPrefix(resolvedPath, absWorkspace+string(filepath.Separator)) && resolvedPath != absWorkspace {
			slog.Error("system-prompt-file symlink resolves outside workspace", "resolved", resolvedPath, "workspace", absWorkspace)
			os.Exit(1)
		}
		data, err := os.ReadFile(resolvedPath)
		if err != nil {
			slog.Error("failed to read system prompt file", "path", promptPath, "error", err)
			os.Exit(1)
		}
		additionalPrompt = string(data)
		slog.Debug("loaded system prompt file", "file", *systemPromptFile, "bytes", len(additionalPrompt))
	}

	// Step 7: Budget-aware prompt assembly
	systemBase := review.BuildSystemBase()
	if additionalPrompt != "" {
		systemBase += "\n\n## Additional Review Instructions\n\n" + additionalPrompt
	}
	sections := budget.Sections{
		SystemBase:  systemBase,
		Patterns:    patterns,
		Conventions: conventions,
		FileContext: fileContext,
		Diff:        diff,
		UserMeta:    review.BuildUserMeta(pr.Title, pr.Body, ciPassed, ciDetails),
	}
	budgetResult := budget.Fit(*llmModel, sections)
	slog.Info("token budget calculated", "tokens", budgetResult.EstTokens, "limit", budget.LimitForModel(*llmModel), "model", *llmModel)
	if len(budgetResult.Trimmed) > 0 {
		slog.Warn("context trimmed to fit budget", "trimmed", budgetResult.Trimmed)
	}

	// Step 8: Call LLM (with retry on parse failure)
	slog.Info("sending request to LLM", "model", *llmModel)
	messages := []llm.Message{
		{Role: "system", Content: budgetResult.SystemPrompt},
		{Role: "user", Content: budgetResult.UserPrompt},
	}

	var response string
	var result *review.ReviewResult
	for attempt := 1; attempt <= 2; attempt++ {
		if attempt > 1 {
			slog.Warn("retrying LLM request after parse failure", "attempt", attempt)
			time.Sleep(time.Second)
		}

		response, err = llmClient.Complete(ctx, messages)
		if err != nil {
			slog.Error("LLM request failed", "model", *llmModel, "error", err, "attempt", attempt)
			if attempt == 2 {
				os.Exit(1)
			}
			continue
		}
		slog.Info("LLM response received", "bytes", len(response), "attempt", attempt)

		// Step 9: Parse response
		result, err = review.ParseResponse(response)
		if err != nil {
			slog.Error("failed to parse LLM response", "error", err, "attempt", attempt)
			if attempt == 2 {
				os.Exit(1)
			}
			continue
		}
		break
	}
	slog.Info("review parsed", "verdict", result.Verdict, "findings", len(result.Findings))

	// Step 10: Format and post review
	reviewBody := review.FormatMarkdown(result, *reviewerName)

	// Add commit footer so readers know which commit was evaluated
	if pr.Head.Sha != "" {
		shortSHA := pr.Head.Sha
		if len(shortSHA) > 8 {
			shortSHA = shortSHA[:8]
		}
		reviewBody += fmt.Sprintf("\n\n---\n*Evaluated against %s*", shortSHA)
	}

	event := review.GiteaEvent(result.Verdict)

	if *dryRun {
		fmt.Println("--- DRY RUN ---")
		fmt.Printf("Event: %s\n\n", event)
		fmt.Println(reviewBody)
		return
	}

	sentinel := fmt.Sprintf("<!-- review-bot:%s -->", *reviewerName)

	// Map findings to inline comments for lines present in the diff
	diffRanges := gitea.ParseDiffNewLines(diff)
	var inlineComments []gitea.ReviewComment
	for _, f := range result.Findings {
		if f.File != "" && f.Line > 0 && diffRanges.Contains(f.File, f.Line) {
			inlineComments = append(inlineComments, gitea.ReviewComment{
				Path:        f.File,
				NewPosition: int64(f.Line),
				Body:        fmt.Sprintf("**[%s]** %s", f.Severity, f.Finding),
			})
		}
	}
	if len(inlineComments) > 0 {
		slog.Debug("attaching inline comments", "count", len(inlineComments))
	}

	// --- Review update strategy ---
	// 1. POST new review first (gets non-stale approval badge on HEAD)
	// 2. Then supersede old review with link to the new one
	// Order matters: post first so we have the new review's URL for the supersede message.
	var oldReviews []gitea.Review
	if *reviewerName != "" {
		existingReviews, err := giteaClient.ListReviews(ctx, owner, repoName, prNumber)
		if err != nil {
			slog.Warn("could not list existing reviews", "pr", prNumber, "error", err)
		} else {
			if hasSharedToken(existingReviews, sentinel) {
				slog.Warn("shared token mode: skipping supersede to avoid clobbering sibling review")
			} else {
				oldReviews = findAllOwnReviews(existingReviews, sentinel)
			}
		}
	}

	// Self-request as reviewer (ensures we appear in required-reviewer checks)
	authUser, err := giteaClient.GetAuthenticatedUser(ctx)
	if err != nil {
		slog.Warn("could not determine authenticated user for reviewer self-request", "error", err)
	} else if authUser != "" {
		if err := giteaClient.RequestReviewer(ctx, owner, repoName, prNumber, authUser); err != nil {
			slog.Warn("could not self-request as reviewer", "user", authUser, "error", err)
		} else {
			slog.Debug("self-requested as reviewer", "user", authUser, "pr", prNumber)
		}
	}

	// POST new review
	slog.Info("posting review", "event", event, "pr", prNumber)
	posted, err := giteaClient.PostReview(ctx, owner, repoName, prNumber, event, reviewBody, inlineComments)
	if err != nil {
		slog.Error("failed to post review", "pr", prNumber, "event", event, "error", err)
		os.Exit(1)
	}
	slog.Info("review posted", "review_id", posted.ID, "user", posted.User.Login, "pr", prNumber)

	// Supersede all old reviews with link to the new one
	if len(oldReviews) > 0 {
		newReviewURL := fmt.Sprintf("%s/%s/%s/pulls/%d#pullrequestreview-%d", strings.TrimRight(*giteaURL, "/"), owner, repoName, prNumber, posted.ID)
		for _, oldReview := range oldReviews {
			cid, err := giteaClient.GetTimelineReviewCommentIDForReview(ctx, owner, repoName, prNumber, oldReview.ID)
			if err != nil {
				slog.Warn("could not find comment ID for old review", "review_id", oldReview.ID, "error", err)
				continue
			}
			supersededBody := buildSupersededBody(oldReview.Body, oldReview.CommitID, newReviewURL, sentinel)
			if err := giteaClient.EditComment(ctx, owner, repoName, cid, supersededBody); err != nil {
				slog.Warn("could not mark old review as superseded", "review_id", oldReview.ID, "comment_id", cid, "error", err)
				continue
			}
			slog.Info("marked old review as superseded", "review_id", oldReview.ID, "new_review_id", posted.ID, "pr", prNumber)

			// Resolve old review's inline comments
			oldComments, err := giteaClient.ListReviewComments(ctx, owner, repoName, prNumber, oldReview.ID)
			if err != nil {
				slog.Warn("could not list old review comments for resolution", "review_id", oldReview.ID, "error", err)
				continue
			}
			resolved, failed := 0, 0
			for _, c := range oldComments {
				if c.ID == 0 {
					continue
				}
				if err := giteaClient.ResolveComment(ctx, owner, repoName, c.ID); err != nil {
					slog.Debug("could not resolve inline comment", "comment_id", c.ID, "error", err)
					failed++
				} else {
					resolved++
				}
			}
			if resolved > 0 {
				slog.Info("resolved old inline comments", "review_id", oldReview.ID, "count", resolved, "pr", prNumber)
			}
			if failed > 0 {
				slog.Warn("some inline comments could not be resolved", "review_id", oldReview.ID, "failed", failed, "pr", prNumber)
			}
		}
	}

}

// fetchFileContext fetches the full content of modified files from the PR branch.
func fetchFileContext(ctx context.Context, client *gitea.Client, owner, repo, ref string, files []gitea.ChangedFile) string {
	var sb strings.Builder
	for _, f := range files {
		if ctx.Err() != nil {
			break
		}
		if f.Status == "removed" {
			continue // Skip deleted files
		}
		content, err := client.GetFileContentRef(ctx, owner, repo, f.Filename, ref)
		if err != nil {
			slog.Warn("could not fetch file content", "file", f.Filename, "error", err)
			continue
		}
		sb.WriteString(fmt.Sprintf("--- %s ---\n", f.Filename))
		sb.WriteString("```\n")
		sb.WriteString(content)
		sb.WriteString("\n```\n\n")
	}
	return sb.String()
}

// fetchPatterns fetches pattern files from one or more external repos.
// patternsRepo is comma-separated list of owner/name repos.
// patternsFiles is comma-separated list of file paths or directories.
// If a path ends with / or is a directory, all files within it are fetched recursively.
func fetchPatterns(ctx context.Context, client *gitea.Client, patternsRepo, patternsFiles string) string {
	var sb strings.Builder

	repos := strings.Split(patternsRepo, ",")
	paths := strings.Split(patternsFiles, ",")

	for _, repoRef := range repos {
		if ctx.Err() != nil {
			break
		}
		repoRef = strings.TrimSpace(repoRef)
		if repoRef == "" {
			continue
		}
		parts := strings.SplitN(repoRef, "/", 2)
		if len(parts) != 2 {
			slog.Warn("invalid patterns-repo format", "repo", repoRef, "expected", "owner/name")
			continue
		}
		owner, repo := parts[0], parts[1]

		for _, path := range paths {
			path = strings.TrimSpace(path)
			if path == "" {
				continue
			}

			files, err := client.GetAllFilesInPath(ctx, owner, repo, path)
			if err != nil {
				slog.Warn("could not fetch patterns", "path", path, "repo", repoRef, "error", err)
				continue
			}

			for filePath, content := range files {
				// Only include markdown and text files as patterns
				if !isPatternFile(filePath) {
					continue
				}
				sb.WriteString(fmt.Sprintf("### %s/%s\n\n%s\n\n", repoRef, filePath, content))
			}
		}
	}
	return sb.String()
}

// isPatternFile returns true if the file should be included as pattern content.
func isPatternFile(path string) bool {
	lower := strings.ToLower(path)
	return strings.HasSuffix(lower, ".md") ||
		strings.HasSuffix(lower, ".txt") ||
		strings.HasSuffix(lower, ".yml") ||
		strings.HasSuffix(lower, ".yaml")
}

// evaluateCIStatus checks if all CI statuses indicate success.
func evaluateCIStatus(statuses []gitea.CommitStatus) (passed bool, details string) {
	if len(statuses) == 0 {
		return true, "no CI statuses found"
	}

	var failed []string
	for _, s := range statuses {
		switch s.Status {
		case "success":
			// good
		case "pending":
			// treat pending as not-failed
		case "failure", "error":
			failed = append(failed, fmt.Sprintf("%s: %s", s.Context, s.Description))
		}
	}

	if len(failed) > 0 {
		return false, strings.Join(failed, "; ")
	}
	return true, "all checks passed"
}

func envOrDefault(key, defaultVal string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return defaultVal
}

func envOrDefaultFloat(key string, defaultVal float64) float64 {
	if v := os.Getenv(key); v != "" {
		f, err := strconv.ParseFloat(v, 64)
		if err == nil {
			return f
		}
	}
	return defaultVal
}

func envOrDefaultInt(key string, defaultVal int) int {
	if v := os.Getenv(key); v != "" {
		i, err := strconv.Atoi(v)
		if err == nil {
			return i
		}
	}
	return defaultVal
}

func envOrDefaultBool(key string, defaultVal bool) bool {
	v := strings.TrimSpace(strings.ToLower(os.Getenv(key)))
	if v == "" {
		return defaultVal
	}
	return v == "true" || v == "1" || v == "yes"
}

// validateReviewerName checks that the name contains only safe characters
// for embedding in an HTML comment sentinel ([a-zA-Z0-9_-]).
func validateReviewerName(name string) error {
	if name == "" {
		return nil
	}
	for _, ch := range name {
		if !((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9') || ch == '-' || ch == '_') {
			return fmt.Errorf("reviewer-name must contain only [a-zA-Z0-9_-] (got %q)", name)
		}
	}
	return nil
}

// buildSupersededBody creates the body for a superseded review: struck-through banner
// with collapsed original content and the commit it was evaluated against.
func buildSupersededBody(originalBody, commitSHA, newReviewURL, sentinel string) string {
	shortSHA := commitSHA
	if len(shortSHA) > 8 {
		shortSHA = shortSHA[:8]
	}
	var sb strings.Builder
	sb.WriteString("~~Original review~~\n\n")
	sb.WriteString("**Superseded** \u2014 [see current review](")
	sb.WriteString(newReviewURL)
	sb.WriteString(") for up-to-date findings.\n\n")
	if shortSHA != "" {
		sb.WriteString("<details><summary>Previous findings (commit ")
		sb.WriteString(shortSHA)
		sb.WriteString(")</summary>\n\n")
	} else {
		sb.WriteString("<details><summary>Previous findings</summary>\n\n")
	}
	sb.WriteString(originalBody)
	sb.WriteString("\n\n</details>\n\n")
	sb.WriteString(sentinel)
	return sb.String()
}

// hasSharedToken detects if another review-bot role posted under the same
// Gitea user. This indicates misconfiguration where two roles share a token
// instead of having separate Gitea accounts. Returns true if shared token
// detected (caller should skip update-in-place logic to avoid clobbering).
func hasSharedToken(reviews []gitea.Review, ownSentinel string) bool {
	ownLogin := ""
	for _, r := range reviews {
		if strings.Contains(r.Body, ownSentinel) {
			ownLogin = r.User.Login
			break
		}
	}
	if ownLogin == "" {
		return false
	}
	for _, r := range reviews {
		if r.User.Login == ownLogin && strings.Contains(r.Body, "<!-- review-bot:") && !strings.Contains(r.Body, ownSentinel) {
			slog.Warn("shared token detected — another review-bot role is using the same Gitea user",
				"sibling_role", extractSentinelName(r.Body), "user", ownLogin)
			return true
		}
	}
	return false
}

// extractSentinelName pulls the reviewer name from a sentinel comment.
func extractSentinelName(body string) string {
	const prefix = "<!-- review-bot:"
	const suffix = " -->"
	idx := strings.Index(body, prefix)
	if idx < 0 {
		return "unknown"
	}
	rest := body[idx+len(prefix):]
	end := strings.Index(rest, suffix)
	if end < 0 {
		return "unknown"
	}
	return rest[:end]
}

// findOwnReview locates the most recent non-superseded review matching the sentinel.
func findOwnReview(reviews []gitea.Review, sentinel string) *gitea.Review {
	var best *gitea.Review
	for i := range reviews {
		if !strings.Contains(reviews[i].Body, sentinel) {
			continue
		}
		if strings.Contains(reviews[i].Body, "~~Original review~~") {
			continue
		}
		if best == nil || reviews[i].ID > best.ID {
			best = &reviews[i]
		}
	}
	return best
}

// findAllOwnReviews returns all non-superseded reviews matching the sentinel.
func findAllOwnReviews(reviews []gitea.Review, sentinel string) []gitea.Review {
	var result []gitea.Review
	for i := range reviews {
		if !strings.Contains(reviews[i].Body, sentinel) {
			continue
		}
		if strings.Contains(reviews[i].Body, "~~Original review~~") {
			continue
		}
		result = append(result, reviews[i])
	}
	return result
}