package adapter

import (
	"sort"
	"sync"
	"time"
)

// State is a publication's lifecycle, per contracts/r1.openapi.yaml's `state`
// enum on listPosts.
type State string

const (
	StatePending    State = "pending"
	StatePublished  State = "published"
	StateFailed     State = "failed"
	StateSuperseded State = "superseded"
)

// Publication is this adapter's own record of a post_id: which Telegram
// message implements it. The evidence store records that a publication
// happened; this is the adapter's mapping, kept separately per
// docs/adapter-contract.md.
type Publication struct {
	PostID         string
	State          State
	TelegramMsgID  int
	Body           string // the rendered text or caption last sent, for edit-detection
	SourceEntryID  string
	Variant        string
	PublishedAt    time.Time
	LastAttemptErr string
}

// Store is the adapter's idempotency mapping from post_id to what was sent.
// It is the adapter's own state, never fluid-core's.
type Store interface {
	Get(postID string) (Publication, bool)
	Put(Publication)
	List(filter ListFilter) []Publication
}

// ListFilter narrows GET /v1/channel-posts, mirroring its query parameters.
type ListFilter struct {
	State         State
	Variant       string
	SourceEntryID string
	Limit         int
}

type memStore struct {
	mu   sync.RWMutex
	byID map[string]Publication
}

// NewMemStore is an in-process idempotency store. It is what one adapter
// instance needs for one channel; nothing here is shared with fluid-core or
// with another channel's adapter instance.
func NewMemStore() Store {
	return &memStore{byID: map[string]Publication{}}
}

func (s *memStore) Get(postID string) (Publication, bool) {
	s.mu.RLock()
	defer s.mu.RUnlock()
	p, ok := s.byID[postID]
	return p, ok
}

func (s *memStore) Put(p Publication) {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.byID[p.PostID] = p
}

func (s *memStore) List(f ListFilter) []Publication {
	s.mu.RLock()
	defer s.mu.RUnlock()
	out := make([]Publication, 0, len(s.byID))
	for _, p := range s.byID {
		if f.State != "" && p.State != f.State {
			continue
		}
		if f.Variant != "" && p.Variant != f.Variant {
			continue
		}
		if f.SourceEntryID != "" && p.SourceEntryID != f.SourceEntryID {
			continue
		}
		out = append(out, p)
	}
	sort.Slice(out, func(i, j int) bool { return out[i].PublishedAt.After(out[j].PublishedAt) })
	if f.Limit > 0 && len(out) > f.Limit {
		out = out[:f.Limit]
	}
	return out
}