package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"ai-workflow-skill/packages/repo-memory-runtime/internal/documents"
	"ai-workflow-skill/packages/repo-memory-runtime/internal/store"
)

func main() {
	if len(os.Args) < 2 {
		usage()
		os.Exit(2)
	}

	switch os.Args[1] {
	case "init":
		if err := runInit(os.Args[2:]); err != nil {
			fatal(err)
		}
	case "add":
		if err := runAdd(os.Args[2:]); err != nil {
			fatal(err)
		}
	case "ingest":
		if err := runIngest(os.Args[2:]); err != nil {
			fatal(err)
		}
	case "search":
		if err := runSearch(os.Args[2:]); err != nil {
			fatal(err)
		}
	case "list":
		if err := runList(os.Args[2:]); err != nil {
			fatal(err)
		}
	case "events":
		if err := runEvents(os.Args[2:]); err != nil {
			fatal(err)
		}
	case "link":
		if err := runLink(os.Args[2:]); err != nil {
			fatal(err)
		}
	case "verify":
		if err := runVerify(os.Args[2:]); err != nil {
			fatal(err)
		}
	case "repos":
		if err := runRepos(os.Args[2:]); err != nil {
			fatal(err)
		}
	default:
		usage()
		os.Exit(2)
	}
}

type stringSliceFlag []string

func (s *stringSliceFlag) String() string {
	return strings.Join(*s, ",")
}

func (s *stringSliceFlag) Set(value string) error {
	*s = append(*s, value)
	return nil
}

func runInit(args []string) error {
	fs := flag.NewFlagSet("init", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	if err := fs.Parse(args); err != nil {
		return err
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	if err := st.Init(context.Background()); err != nil {
		return err
	}

	fmt.Printf("initialized %s\n", *dbPath)
	return nil
}

func runIngest(args []string) error {
	fs := flag.NewFlagSet("ingest", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	repoPath := fs.String("repo", "", "Repository root")
	scanPath := fs.String("path", "docs/ai", "Relative path under repo to scan for markdown")
	if err := fs.Parse(args); err != nil {
		return err
	}
	if strings.TrimSpace(*repoPath) == "" {
		return fmt.Errorf("--repo is required")
	}

	absRepo, err := filepath.Abs(*repoPath)
	if err != nil {
		return err
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	if err := st.Init(context.Background()); err != nil {
		return err
	}

	gitState := detectGitState(absRepo)
	if _, err := st.UpsertRepo(context.Background(), store.RepoState{
		RootPath:       absRepo,
		Name:           filepath.Base(absRepo),
		VCS:            "git",
		LastSeenBranch: gitState.branch,
		LastSeenCommit: gitState.commit,
	}); err != nil {
		return err
	}

	docs, err := documents.LoadRepo(absRepo, *scanPath)
	if err != nil {
		return err
	}
	if len(docs) == 0 {
		return fmt.Errorf("no markdown files found under %s", filepath.Join(absRepo, *scanPath))
	}

	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()

	for _, doc := range docs {
		if err := st.ImportDocument(ctx, doc, store.RepoState{
			RootPath:       absRepo,
			Name:           filepath.Base(absRepo),
			VCS:            "git",
			LastSeenBranch: gitState.branch,
			LastSeenCommit: gitState.commit,
		}); err != nil {
			return fmt.Errorf("ingest %s: %w", doc.DocPath, err)
		}
	}

	fmt.Printf("ingested %d docs from %s\n", len(docs), absRepo)
	return nil
}

func runAdd(args []string) error {
	fs := flag.NewFlagSet("add", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	repoPath := fs.String("repo", "", "Repository root")
	kind := fs.String("kind", "", "Knowledge kind, e.g. term|chain|danger")
	key := fs.String("key", "", "Stable entry key")
	title := fs.String("title", "", "Display title")
	summary := fs.String("summary", "", "Short summary")
	detail := fs.String("detail", "", "Detailed markdown text")
	status := fs.String("status", "draft", "Entry status")
	confidence := fs.Float64("confidence", 0.7, "Confidence from 0 to 1")
	scopeBranch := fs.String("scope-branch", "", "Optional branch scope")
	scopeModule := fs.String("scope-module", "", "Optional module scope")
	scopePath := fs.String("scope-path-prefix", "", "Optional path prefix scope")
	sourcePath := fs.String("source-path", "", "Main evidence path")
	sourceLine := fs.Int("source-line", 0, "Main evidence line")
	var aliases stringSliceFlag
	var deps stringSliceFlag
	fs.Var(&aliases, "alias", "Alias for this entry (repeatable)")
	fs.Var(&deps, "dep", "Dependency in type:locator[:hard|soft] format (repeatable)")
	if err := fs.Parse(args); err != nil {
		return err
	}
	if strings.TrimSpace(*repoPath) == "" {
		return fmt.Errorf("--repo is required")
	}

	absRepo, err := filepath.Abs(*repoPath)
	if err != nil {
		return err
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	if err := st.Init(context.Background()); err != nil {
		return err
	}

	gitState := detectGitState(absRepo)
	if _, err := st.UpsertRepo(context.Background(), store.RepoState{
		RootPath:       absRepo,
		Name:           filepath.Base(absRepo),
		VCS:            "git",
		LastSeenBranch: gitState.branch,
		LastSeenCommit: gitState.commit,
	}); err != nil {
		return err
	}

	input := store.EntryInput{
		RepoRoot:         absRepo,
		Kind:             *kind,
		Key:              *key,
		Title:            *title,
		Summary:          *summary,
		DetailMD:         *detail,
		Status:           *status,
		Confidence:       *confidence,
		ScopeBranch:      *scopeBranch,
		ScopeModule:      *scopeModule,
		ScopePathPrefix:  *scopePath,
		SourcePath:       relativize(absRepo, *sourcePath),
		SourceLine:       *sourceLine,
		VerifiedAt:       time.Now().UTC().Format(time.RFC3339),
		VerifiedOnCommit: gitState.commit,
		Aliases:          aliases,
		Dependencies:     parseDeps(absRepo, deps),
	}
	entryID, err := st.UpsertEntry(context.Background(), input)
	if err != nil {
		return err
	}

	fmt.Printf("upserted entry %d (%s:%s)\n", entryID, input.Kind, input.Key)
	return nil
}

func runSearch(args []string) error {
	fs := flag.NewFlagSet("search", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	query := fs.String("query", "", "Search query")
	repo := fs.String("repo", "", "Optional repo path filter (substring match)")
	limit := fs.Int("limit", 10, "Result limit")
	if err := fs.Parse(args); err != nil {
		return err
	}
	if strings.TrimSpace(*query) == "" {
		return fmt.Errorf("--query is required")
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	results, err := st.Search(context.Background(), store.SearchParams{
		Query:      *query,
		RepoFilter: *repo,
		Limit:      *limit,
	})
	if err != nil {
		return err
	}
	if len(results) == 0 {
		fmt.Println("no results")
		return nil
	}

	for i, r := range results {
		fmt.Printf("%d. [%s] %s:%s [%s]\n", i+1, filepath.Base(r.RepoPath), r.Kind, r.Key, r.Status)
		fmt.Printf("   %s\n", r.Title)
		fmt.Printf("   %s\n", r.Snippet)
	}
	return nil
}

func runRepos(args []string) error {
	fs := flag.NewFlagSet("repos", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	if err := fs.Parse(args); err != nil {
		return err
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	repos, err := st.ListRepos(context.Background())
	if err != nil {
		return err
	}
	if len(repos) == 0 {
		fmt.Println("no repos")
		return nil
	}

	for _, repo := range repos {
		fmt.Printf("- %s (%d entries, updated %s)\n", repo.Path, repo.EntryCount, repo.UpdatedAt.Format(time.RFC3339))
	}
	return nil
}

func runList(args []string) error {
	fs := flag.NewFlagSet("list", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	repo := fs.String("repo", "", "Optional repo path filter (substring match)")
	kind := fs.String("kind", "", "Optional knowledge kind filter")
	status := fs.String("status", "", "Optional status filter")
	limit := fs.Int("limit", 20, "Result limit")
	if err := fs.Parse(args); err != nil {
		return err
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	items, err := st.ListEntries(context.Background(), store.ListParams{
		RepoFilter: *repo,
		Kind:       *kind,
		Status:     *status,
		Limit:      *limit,
	})
	if err != nil {
		return err
	}
	if len(items) == 0 {
		fmt.Println("no entries")
		return nil
	}

	for _, item := range items {
		fmt.Printf("- #%d [%s] %s:%s [%s]\n", item.ID, filepath.Base(item.RepoPath), item.Kind, item.Key, item.Status)
		fmt.Printf("  %s\n", item.Summary)
	}
	return nil
}

func runEvents(args []string) error {
	fs := flag.NewFlagSet("events", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	id := fs.Int64("id", 0, "Entry id")
	repo := fs.String("repo", "", "Repo root when resolving by kind/key")
	kind := fs.String("kind", "", "Knowledge kind when resolving by kind/key")
	key := fs.String("key", "", "Knowledge key when resolving by kind/key")
	limit := fs.Int("limit", 20, "Result limit")
	if err := fs.Parse(args); err != nil {
		return err
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	ref, err := buildEntryRef(*id, *repo, *kind, *key)
	if err != nil {
		return err
	}
	entry, err := st.ResolveEntry(context.Background(), ref)
	if err != nil {
		return err
	}
	events, err := st.ListEvents(context.Background(), entry.ID, *limit)
	if err != nil {
		return err
	}
	if len(events) == 0 {
		fmt.Println("no events")
		return nil
	}

	fmt.Printf("%s:%s [%s] #%d\n", entry.Kind, entry.Key, entry.Status, entry.ID)
	for _, ev := range events {
		line := fmt.Sprintf("- %s %s", ev.CreatedAt.Format(time.RFC3339), ev.EventType)
		if ev.FromStatus != "" || ev.ToStatus != "" {
			line += fmt.Sprintf(" (%s -> %s)", emptyDash(ev.FromStatus), emptyDash(ev.ToStatus))
		}
		fmt.Println(line)
		if ev.Reason != "" {
			fmt.Printf("  reason: %s\n", ev.Reason)
		}
	}
	return nil
}

func runLink(args []string) error {
	fs := flag.NewFlagSet("link", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	fromID := fs.Int64("from-id", 0, "From entry id")
	toID := fs.Int64("to-id", 0, "To entry id")
	relation := fs.String("relation", "", "Link relation")
	if err := fs.Parse(args); err != nil {
		return err
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	if err := st.AddLink(context.Background(), *fromID, *toID, *relation); err != nil {
		return err
	}

	fmt.Printf("linked #%d -[%s]-> #%d\n", *fromID, *relation, *toID)
	return nil
}

func runVerify(args []string) error {
	fs := flag.NewFlagSet("verify", flag.ContinueOnError)
	dbPath := fs.String("db", "repo-memory.db", "SQLite database path")
	repo := fs.String("repo", "", "Optional repo root to verify; if omitted, verify all known repos")
	if err := fs.Parse(args); err != nil {
		return err
	}

	st, err := store.Open(*dbPath)
	if err != nil {
		return err
	}
	defer st.Close()

	var repoRoots []string
	if strings.TrimSpace(*repo) != "" {
		absRepo, err := filepath.Abs(*repo)
		if err != nil {
			return err
		}
		repoRoots = []string{absRepo}
	} else {
		repos, err := st.ListRepos(context.Background())
		if err != nil {
			return err
		}
		for _, repoInfo := range repos {
			repoRoots = append(repoRoots, repoInfo.Path)
		}
	}
	if len(repoRoots) == 0 {
		fmt.Println("no repos")
		return nil
	}

	for _, repoRoot := range repoRoots {
		gitState := detectGitState(repoRoot)
		if gitState.commit == "" {
			fmt.Printf("%s: skipped (not a git repo or no HEAD)\n", repoRoot)
			continue
		}
		if _, err := st.UpsertRepo(context.Background(), store.RepoState{
			RootPath:       repoRoot,
			Name:           filepath.Base(repoRoot),
			VCS:            "git",
			LastSeenBranch: gitState.branch,
			LastSeenCommit: gitState.commit,
		}); err != nil {
			return err
		}

		candidates, err := st.ListVerifyCandidates(context.Background(), repoRoot)
		if err != nil {
			return err
		}
		changedCount := 0
		staleCount := 0
		for _, candidate := range candidates {
			nextStatus, reason, err := verifyCandidate(repoRoot, candidate)
			if err != nil {
				return fmt.Errorf("verify %s:%s: %w", candidate.Kind, candidate.Key, err)
			}
			if nextStatus != candidate.Status {
				switch nextStatus {
				case "needs_review":
					changedCount++
				case "stale":
					staleCount++
				}
			}
			if err := st.ApplyVerificationResult(context.Background(), candidate.ID, gitState.commit, nextStatus, reason); err != nil {
				return err
			}
		}
		fmt.Printf("%s: verified %d entries, %d downgraded, %d stale\n", repoRoot, len(candidates), changedCount, staleCount)
	}

	return nil
}

func usage() {
	fmt.Fprintf(os.Stderr, `repo-memory: repo memory CLI

Usage:
  repo-memory init   --db repo-memory.db
  repo-memory add    --db repo-memory.db --repo /path/to/repo --kind term --key AITask --summary "..."
  repo-memory ingest --db repo-memory.db --repo /path/to/repo [--path docs/ai]
  repo-memory search --db repo-memory.db --query "actionCode fill" [--repo zeus]
  repo-memory list   --db repo-memory.db [--repo zeus] [--kind term] [--status confirmed]
  repo-memory events --db repo-memory.db --id 1
  repo-memory link   --db repo-memory.db --from-id 1 --to-id 2 --relation related_to
  repo-memory verify --db repo-memory.db [--repo /path/to/repo]
  repo-memory repos  --db repo-memory.db
`)
}

func fatal(err error) {
	fmt.Fprintln(os.Stderr, err)
	os.Exit(1)
}

type gitState struct {
	branch string
	commit string
}

func detectGitState(repo string) gitState {
	return gitState{
		branch: strings.TrimSpace(run(repo, "git", "-C", repo, "rev-parse", "--abbrev-ref", "HEAD")),
		commit: strings.TrimSpace(run(repo, "git", "-C", repo, "rev-parse", "HEAD")),
	}
}

func run(dir string, name string, args ...string) string {
	cmd := exec.Command(name, args...)
	cmd.Dir = dir
	out, err := cmd.Output()
	if err != nil {
		return ""
	}
	return string(out)
}

func parseDeps(repoRoot string, values []string) []store.DependencyInput {
	var deps []store.DependencyInput
	for _, raw := range values {
		parts := strings.Split(raw, ":")
		if len(parts) < 2 {
			continue
		}
		dep := store.DependencyInput{
			Type:    strings.TrimSpace(parts[0]),
			Locator: strings.TrimSpace(parts[1]),
			IsHard:  true,
		}
		if dep.Type == "file" || dep.Type == "dir" || dep.Type == "glob" {
			dep.Locator = relativize(repoRoot, dep.Locator)
		}
		if len(parts) >= 3 {
			mode := strings.ToLower(strings.TrimSpace(parts[2]))
			if mode == "soft" {
				dep.IsHard = false
			}
		}
		if dep.Type != "" && dep.Locator != "" {
			deps = append(deps, dep)
		}
	}
	return deps
}

func relativize(repoRoot, maybePath string) string {
	if strings.TrimSpace(maybePath) == "" {
		return ""
	}
	if !filepath.IsAbs(maybePath) {
		return filepath.ToSlash(maybePath)
	}
	rel, err := filepath.Rel(repoRoot, maybePath)
	if err != nil {
		return filepath.ToSlash(maybePath)
	}
	if strings.HasPrefix(rel, "..") {
		return filepath.ToSlash(maybePath)
	}
	return filepath.ToSlash(rel)
}

func buildEntryRef(id int64, repo, kind, key string) (store.EntryRef, error) {
	if id > 0 {
		return store.EntryRef{ID: id}, nil
	}
	if strings.TrimSpace(repo) == "" || strings.TrimSpace(kind) == "" || strings.TrimSpace(key) == "" {
		return store.EntryRef{}, fmt.Errorf("either --id or --repo+--kind+--key is required")
	}
	absRepo, err := filepath.Abs(repo)
	if err != nil {
		return store.EntryRef{}, err
	}
	return store.EntryRef{RepoRoot: absRepo, Kind: kind, Key: key}, nil
}

func verifyCandidate(repoRoot string, candidate store.VerifyCandidate) (string, string, error) {
	if strings.TrimSpace(candidate.VerifiedOnCommit) == "" {
		return "needs_review", "missing verified_on_commit", nil
	}

	var paths []string
	for _, dep := range candidate.Dependencies {
		if !dep.IsHard {
			continue
		}
		switch dep.Type {
		case "file", "dir", "glob":
			paths = append(paths, dep.Locator)
			if dep.Type == "file" {
				absPath := dep.Locator
				if !filepath.IsAbs(absPath) {
					absPath = filepath.Join(repoRoot, dep.Locator)
				}
				if _, err := os.Stat(absPath); err != nil {
					if os.IsNotExist(err) {
						return "stale", "hard dependency missing: " + dep.Locator, nil
					}
					return candidate.Status, "", err
				}
			}
		}
	}
	if len(paths) == 0 {
		return candidate.Status, "", nil
	}

	changed, err := hasCommittedChanges(repoRoot, candidate.VerifiedOnCommit, paths)
	if err != nil {
		return candidate.Status, "", err
	}
	dirty, err := hasWorkingTreeChanges(repoRoot, paths)
	if err != nil {
		return candidate.Status, "", err
	}
	if changed || dirty {
		return "needs_review", "dependency paths changed since verification", nil
	}
	return candidate.Status, "", nil
}

func hasCommittedChanges(repoRoot, fromCommit string, paths []string) (bool, error) {
	args := append([]string{"-C", repoRoot, "diff", "--name-only", fromCommit + "..HEAD", "--"}, paths...)
	out, err := exec.Command("git", args...).Output()
	if err != nil {
		return false, err
	}
	return strings.TrimSpace(string(out)) != "", nil
}

func hasWorkingTreeChanges(repoRoot string, paths []string) (bool, error) {
	args := append([]string{"-C", repoRoot, "status", "--porcelain", "--"}, paths...)
	out, err := exec.Command("git", args...).Output()
	if err != nil {
		return false, err
	}
	return strings.TrimSpace(string(out)) != "", nil
}

func emptyDash(value string) string {
	if strings.TrimSpace(value) == "" {
		return "-"
	}
	return value
}