package repository

import (
	"context"
	"sort"
	"sync"

	"apps/backend/internal/module/scout/domain"
)

type MemoryStore struct {
	mu       sync.Mutex
	brands   map[string]*domain.Brand
	products map[string]*domain.Product
	active   map[int64]string
	posts    map[string]*domain.Post
	runs     map[string]*domain.Run
	seen     map[string]struct{}
	hw       map[string]*domain.Homework // key owner|theme
	crawler  map[int64]*domain.CrawlerSession
}

func NewMemory() *MemoryStore {
	return &MemoryStore{
		brands: map[string]*domain.Brand{}, products: map[string]*domain.Product{},
		active: map[int64]string{}, posts: map[string]*domain.Post{},
		runs: map[string]*domain.Run{}, seen: map[string]struct{}{},
		hw: map[string]*domain.Homework{}, crawler: map[int64]*domain.CrawlerSession{},
	}
}

func cloneRun(r *domain.Run) *domain.Run {
	if r == nil {
		return nil
	}
	cp := *r
	cp.ShortfallReasons = append([]string(nil), r.ShortfallReasons...)
	return &cp
}

func clonePost(p *domain.Post) *domain.Post {
	if p == nil {
		return nil
	}
	cp := *p
	return &cp
}

func compareRuns(a, b *domain.Run) bool {
	if a.CreatedAt != b.CreatedAt {
		return a.CreatedAt > b.CreatedAt
	}
	return a.ID > b.ID
}

func comparePosts(a, b *domain.Post) bool {
	if a.Score != b.Score {
		return a.Score > b.Score
	}
	aKnown := a.PostedAt > 0
	bKnown := b.PostedAt > 0
	if aKnown != bKnown {
		return aKnown
	}
	if aKnown && a.PostedAt != b.PostedAt {
		return a.PostedAt > b.PostedAt
	}
	if a.CreatedAt != b.CreatedAt {
		return a.CreatedAt > b.CreatedAt
	}
	return a.ID > b.ID
}

func postIdentity(p *domain.Post) string {
	if p.ExternalID != "" {
		return "external:" + p.ExternalID
	}
	if p.Permalink != "" {
		return "url:" + p.Permalink
	}
	return "id:" + p.ID
}

func uniquePosts(items []*domain.Post) []*domain.Post {
	sort.Slice(items, func(i, j int) bool { return comparePosts(items[i], items[j]) })
	seen := make(map[string]struct{}, len(items))
	out := make([]*domain.Post, 0, len(items))
	for _, p := range items {
		identity := postIdentity(p)
		if _, exists := seen[identity]; exists {
			continue
		}
		seen[identity] = struct{}{}
		out = append(out, p)
	}
	return out
}

func legacyRunFromPosts(ownerUID int64, themeKey string, posts []*domain.Post) *domain.Run {
	var latest int64
	var label string
	var brandID, mode string
	for _, p := range posts {
		if p.CreatedAt > latest {
			latest = p.CreatedAt
			label = p.ThemeLabel
			brandID = p.BrandID
			mode = p.ScoutMode
		}
	}
	if latest == 0 {
		latest = domain.NowNano()
	}
	return &domain.Run{
		ID: domain.LegacyRunID(themeKey), OwnerUID: ownerUID, JobID: "legacy",
		ThemeKey: themeKey, ThemeLabel: label, Intent: label, Mode: mode,
		BrandID: brandID, TargetCount: len(posts), Status: domain.RunSucceeded,
		SearchedCount: len(posts), EligibleCount: len(posts), PendingCount: countPending(posts),
		CreatedAt: latest, CompletedAt: latest,
	}
}

func countPending(posts []*domain.Post) int {
	n := 0
	for _, p := range posts {
		if p.OutreachStatus == domain.OutreachNew || p.OutreachStatus == domain.OutreachDrafted {
			n++
		}
	}
	return n
}

func identityKey(uid int64, identity string) string {
	return formatUID(uid) + "|" + identity
}

func key(uid int64, theme string) string {
	return formatUID(uid) + "|" + theme
}
func formatUID(uid int64) string {
	if uid == 0 {
		return "0"
	}
	neg := uid < 0
	if neg {
		uid = -uid
	}
	var b [32]byte
	i := len(b)
	for uid > 0 {
		i--
		b[i] = byte('0' + uid%10)
		uid /= 10
	}
	if neg {
		i--
		b[i] = '-'
	}
	return string(b[i:])
}

func (s *MemoryStore) SaveBrand(_ context.Context, b *domain.Brand) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	cp := *b
	s.brands[b.ID] = &cp
	return nil
}
func (s *MemoryStore) GetBrand(_ context.Context, id string) (*domain.Brand, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	b, ok := s.brands[id]
	if !ok {
		return nil, domain.ErrNotFound
	}
	cp := *b
	return &cp, nil
}
func (s *MemoryStore) ListBrands(_ context.Context, ownerUID int64) ([]*domain.Brand, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	var out []*domain.Brand
	for _, b := range s.brands {
		if b.OwnerUID == ownerUID {
			cp := *b
			out = append(out, &cp)
		}
	}
	return out, nil
}
func (s *MemoryStore) DeleteBrand(_ context.Context, id string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	if _, ok := s.brands[id]; !ok {
		return domain.ErrNotFound
	}
	delete(s.brands, id)
	return nil
}

func (s *MemoryStore) SaveProduct(_ context.Context, p *domain.Product) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	cp := *p
	if p.MatchTags != nil {
		cp.MatchTags = append([]string(nil), p.MatchTags...)
	}
	if p.PainPoints != nil {
		cp.PainPoints = append([]string(nil), p.PainPoints...)
	}
	if p.ProviderCapabilityTerms != nil {
		cp.ProviderCapabilityTerms = append([]string(nil), p.ProviderCapabilityTerms...)
	}
	if p.ProviderExcludeTerms != nil {
		cp.ProviderExcludeTerms = append([]string(nil), p.ProviderExcludeTerms...)
	}
	s.products[p.ID] = &cp
	return nil
}
func (s *MemoryStore) GetProduct(_ context.Context, id string) (*domain.Product, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p, ok := s.products[id]
	if !ok {
		return nil, domain.ErrNotFound
	}
	return copyProduct(p), nil
}
func (s *MemoryStore) ListProducts(_ context.Context, ownerUID int64, brandID string) ([]*domain.Product, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	var out []*domain.Product
	for _, p := range s.products {
		if p.OwnerUID != ownerUID {
			continue
		}
		if brandID != "" && p.BrandID != brandID {
			continue
		}
		out = append(out, copyProduct(p))
	}
	return out, nil
}
func (s *MemoryStore) DeleteProduct(_ context.Context, id string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	if _, ok := s.products[id]; !ok {
		return domain.ErrNotFound
	}
	delete(s.products, id)
	return nil
}
func copyProduct(p *domain.Product) *domain.Product {
	cp := *p
	if p.MatchTags != nil {
		cp.MatchTags = append([]string(nil), p.MatchTags...)
	}
	if p.PainPoints != nil {
		cp.PainPoints = append([]string(nil), p.PainPoints...)
	}
	if p.ProviderCapabilityTerms != nil {
		cp.ProviderCapabilityTerms = append([]string(nil), p.ProviderCapabilityTerms...)
	}
	if p.ProviderExcludeTerms != nil {
		cp.ProviderExcludeTerms = append([]string(nil), p.ProviderExcludeTerms...)
	}
	return &cp
}

func (s *MemoryStore) GetActiveBrandID(_ context.Context, ownerUID int64) (string, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.active[ownerUID], nil
}
func (s *MemoryStore) SetActiveBrandID(_ context.Context, ownerUID int64, brandID string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.active[ownerUID] = brandID
	return nil
}

func (s *MemoryStore) SavePost(_ context.Context, p *domain.Post) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	cp := *p
	s.posts[p.ID] = &cp
	return nil
}
func (s *MemoryStore) GetPost(_ context.Context, id string) (*domain.Post, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p, ok := s.posts[id]
	if !ok {
		return nil, domain.ErrNotFound
	}
	cp := *p
	return &cp, nil
}
func (s *MemoryStore) ListPosts(_ context.Context, ownerUID int64, brandID string) ([]*domain.Post, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	var out []*domain.Post
	for _, p := range s.posts {
		if p.OwnerUID != ownerUID {
			continue
		}
		if brandID != "" && p.BrandID != brandID {
			continue
		}
		cp := *p
		out = append(out, &cp)
	}
	sort.Slice(out, func(i, j int) bool { return comparePosts(out[i], out[j]) })
	return out, nil
}
func (s *MemoryStore) DeletePost(_ context.Context, id string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	if _, ok := s.posts[id]; !ok {
		return domain.ErrNotFound
	}
	delete(s.posts, id)
	return nil
}
func (s *MemoryStore) DeletePostsByTheme(_ context.Context, ownerUID int64, themeKey string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	for id, p := range s.posts {
		if p.OwnerUID == ownerUID && p.ThemeKey == themeKey {
			delete(s.posts, id)
		}
	}
	return nil
}

func (s *MemoryStore) SaveHomework(_ context.Context, h *domain.Homework) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	cp := *h
	s.hw[key(h.OwnerUID, h.ThemeKey)] = &cp
	return nil
}
func (s *MemoryStore) GetHomework(_ context.Context, ownerUID int64, themeKey string) (*domain.Homework, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	h, ok := s.hw[key(ownerUID, themeKey)]
	if !ok {
		return nil, domain.ErrNotFound
	}
	cp := *h
	return &cp, nil
}
func (s *MemoryStore) ListHomework(_ context.Context, ownerUID int64) ([]*domain.Homework, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	var out []*domain.Homework
	for _, h := range s.hw {
		if h.OwnerUID == ownerUID {
			cp := *h
			out = append(out, &cp)
		}
	}
	return out, nil
}
func (s *MemoryStore) DeleteHomework(_ context.Context, ownerUID int64, themeKey string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	k := key(ownerUID, themeKey)
	if _, ok := s.hw[k]; !ok {
		return domain.ErrNotFound
	}
	delete(s.hw, k)
	return nil
}

func (s *MemoryStore) GetCrawlerSession(_ context.Context, ownerUID int64) (*domain.CrawlerSession, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	c, ok := s.crawler[ownerUID]
	if !ok || c.StorageStateEnc == "" {
		return nil, domain.ErrNotFound
	}
	cp := *c
	return &cp, nil
}
func (s *MemoryStore) SetCrawlerSession(_ context.Context, sess *domain.CrawlerSession) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	cp := *sess
	s.crawler[sess.OwnerUID] = &cp
	return nil
}
func (s *MemoryStore) ClearCrawlerSession(_ context.Context, ownerUID int64) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	delete(s.crawler, ownerUID)
	return nil
}

func (s *MemoryStore) CreateRun(_ context.Context, r *domain.Run) error {
	if r == nil || r.ID == "" || r.OwnerUID == 0 {
		return domain.ErrValidation
	}
	s.mu.Lock()
	defer s.mu.Unlock()
	if _, exists := s.runs[r.ID]; exists {
		return domain.ErrValidation
	}
	s.runs[r.ID] = cloneRun(r)
	return nil
}

func (s *MemoryStore) GetRun(_ context.Context, ownerUID int64, id string) (*domain.Run, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	r, ok := s.runs[id]
	if ok && r.OwnerUID == ownerUID {
		return cloneRun(r), nil
	}
	if themeKey, legacy := domain.LegacyThemeKey(id); legacy {
		items := make([]*domain.Post, 0)
		for _, p := range s.posts {
			if p.OwnerUID == ownerUID && p.RunID == "" && p.ThemeKey == themeKey {
				items = append(items, clonePost(p))
			}
		}
		items = uniquePosts(items)
		if len(items) > 0 {
			return legacyRunFromPosts(ownerUID, themeKey, items), nil
		}
	}
	return nil, domain.ErrNotFound
}

func (s *MemoryStore) ListRuns(_ context.Context, filter domain.RunFilter) (domain.RunPage, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	page := domain.NormalizePage(filter.Page, filter.PageSize)
	items := make([]*domain.Run, 0)
	for _, r := range s.runs {
		if r.OwnerUID != filter.OwnerUID || (filter.BrandID != "" && r.BrandID != filter.BrandID) || (filter.Mode != "" && r.Mode != filter.Mode) {
			continue
		}
		items = append(items, cloneRun(r))
	}
	legacyGroups := map[string][]*domain.Post{}
	for _, p := range s.posts {
		if p.OwnerUID != filter.OwnerUID || p.RunID != "" {
			continue
		}
		if filter.BrandID != "" && p.BrandID != filter.BrandID {
			continue
		}
		if filter.Mode != "" && p.ScoutMode != filter.Mode {
			continue
		}
		legacyGroups[p.ThemeKey] = append(legacyGroups[p.ThemeKey], clonePost(p))
	}
	for themeKey, posts := range legacyGroups {
		items = append(items, legacyRunFromPosts(filter.OwnerUID, themeKey, uniquePosts(posts)))
	}
	sort.Slice(items, func(i, j int) bool { return compareRuns(items[i], items[j]) })
	total := int64(len(items))
	page = page.WithTotal(total)
	start := (page.Page - 1) * page.PageSize
	if start >= len(items) {
		return domain.RunPage{Items: []*domain.Run{}, Pagination: page}, nil
	}
	end := start + page.PageSize
	if end > len(items) {
		end = len(items)
	}
	return domain.RunPage{Items: items[start:end], Pagination: page}, nil
}

func (s *MemoryStore) ListRunPosts(_ context.Context, ownerUID int64, runID string, requestedPage, requestedSize int) (domain.RunPostPage, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	r, ok := s.runs[runID]
	legacyTheme, isLegacy := domain.LegacyThemeKey(runID)
	if isLegacy {
		items := make([]*domain.Post, 0)
		for _, p := range s.posts {
			if p.OwnerUID == ownerUID && p.RunID == "" && p.ThemeKey == legacyTheme {
				items = append(items, clonePost(p))
			}
		}
		items = uniquePosts(items)
		if len(items) == 0 {
			return domain.RunPostPage{}, domain.ErrNotFound
		}
		r = legacyRunFromPosts(ownerUID, legacyTheme, items)
		ok = true
	}
	if !ok || r.OwnerUID != ownerUID {
		return domain.RunPostPage{}, domain.ErrNotFound
	}
	page := domain.NormalizePage(requestedPage, requestedSize)
	if r.Status != domain.RunSucceeded {
		return domain.RunPostPage{Run: cloneRun(r), Items: []*domain.Post{}, Pagination: page.WithTotal(0)}, nil
	}
	items := make([]*domain.Post, 0)
	for _, p := range s.posts {
		if p.OwnerUID != ownerUID {
			continue
		}
		if (isLegacy && p.RunID == "" && p.ThemeKey == legacyTheme) || (!isLegacy && p.RunID == runID) {
			items = append(items, clonePost(p))
		}
	}
	items = uniquePosts(items)
	page = page.WithTotal(int64(len(items)))
	start := (page.Page - 1) * page.PageSize
	if start >= len(items) {
		return domain.RunPostPage{Run: cloneRun(r), Items: []*domain.Post{}, Pagination: page}, nil
	}
	end := start + page.PageSize
	if end > len(items) {
		end = len(items)
	}
	return domain.RunPostPage{Run: cloneRun(r), Items: items[start:end], Pagination: page}, nil
}

func (s *MemoryStore) ReplaceRunGuarded(_ context.Context, ownerUID int64, id string, expected []string, replacement *domain.Run) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	current, ok := s.runs[id]
	if !ok || current.OwnerUID != ownerUID {
		return domain.ErrNotFound
	}
	if len(expected) > 0 {
		allowed := false
		for _, status := range expected {
			if current.Status == status {
				allowed = true
				break
			}
		}
		if !allowed {
			return domain.ErrIllegalRunStatus
		}
	}
	if replacement == nil || replacement.ID != id {
		return domain.ErrValidation
	}
	if replacement.Status != current.Status && !domain.CanTransitionRun(current.Status, replacement.Status) {
		return domain.ErrIllegalRunStatus
	}
	cp := cloneRun(replacement)
	cp.OwnerUID = ownerUID
	s.runs[id] = cp
	return nil
}

func (s *MemoryStore) DeleteRun(_ context.Context, ownerUID int64, id string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	r, ok := s.runs[id]
	if !ok {
		if themeKey, legacy := domain.LegacyThemeKey(id); legacy {
			found := false
			for postID, p := range s.posts {
				if p.OwnerUID == ownerUID && p.RunID == "" && p.ThemeKey == themeKey {
					delete(s.posts, postID)
					found = true
				}
			}
			if found {
				return nil
			}
		}
	}
	if !ok || r.OwnerUID != ownerUID {
		return domain.ErrNotFound
	}
	delete(s.runs, id)
	for postID, p := range s.posts {
		if p.OwnerUID == ownerUID && p.RunID == id {
			delete(s.posts, postID)
		}
	}
	return nil
}

func (s *MemoryStore) PublishRunPosts(_ context.Context, ownerUID int64, runID string, posts []*domain.Post) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	r, ok := s.runs[runID]
	if !ok || r.OwnerUID != ownerUID {
		return domain.ErrNotFound
	}
	for _, p := range posts {
		if p == nil || p.ID == "" || p.OwnerUID != ownerUID || p.RunID != runID {
			return domain.ErrValidation
		}
	}
	for _, p := range posts {
		s.posts[p.ID] = clonePost(p)
	}
	return nil
}

func (s *MemoryStore) HasSeenIdentity(_ context.Context, ownerUID int64, identity string) (bool, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if identity == "" {
		return false, domain.ErrValidation
	}
	_, ok := s.seen[identityKey(ownerUID, identity)]
	return ok, nil
}

func (s *MemoryStore) MarkSeenIdentity(_ context.Context, ownerUID int64, identity, _ string, _ int64) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	if identity == "" {
		return domain.ErrValidation
	}
	s.seen[identityKey(ownerUID, identity)] = struct{}{}
	return nil
}

var _ domain.Repository = (*MemoryStore)(nil)