package api

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"sync"
	"testing"
	"time"

	"git.yeij.top/AskaEth/Cyrene_v2/services/gateway/store"
)

// fakeChatStore is an in-memory ChatStorer for tests.
type fakeChatStore struct {
	mu       sync.Mutex
	sessions map[string]*store.Session
	messages map[string][]store.Message
	nextID   int64
}

func newFakeChatStore() *fakeChatStore {
	return &fakeChatStore{sessions: map[string]*store.Session{}, messages: map[string][]store.Message{}}
}

func (f *fakeChatStore) CreateSession(_ context.Context, id, userID, title string) (*store.Session, error) {
	f.mu.Lock()
	defer f.mu.Unlock()
	s := &store.Session{ID: id, UserID: userID, Title: title, CreatedAt: time.Now(), UpdatedAt: time.Now()}
	f.sessions[id] = s
	return s, nil
}

func (f *fakeChatStore) ListSessions(_ context.Context, userID string) ([]store.Session, error) {
	f.mu.Lock()
	defer f.mu.Unlock()
	out := []store.Session{}
	for _, s := range f.sessions {
		if s.UserID == userID {
			out = append(out, *s)
		}
	}
	return out, nil
}

func (f *fakeChatStore) DeleteSession(_ context.Context, id, userID string) error {
	f.mu.Lock()
	defer f.mu.Unlock()
	if _, ok := f.sessions[id]; !ok {
		return fmt.Errorf("session not found")
	}
	delete(f.sessions, id)
	delete(f.messages, id)
	return nil
}

func (f *fakeChatStore) AddMessage(sessionID, role, content string) {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.nextID++
	f.messages[sessionID] = append(f.messages[sessionID], store.Message{
		ID: f.nextID, SessionID: sessionID, Role: role, Content: content, CreatedAt: time.Now(),
	})
}

func (f *fakeChatStore) ListMessages(_ context.Context, sessionID string, limit int) ([]store.Message, error) {
	f.mu.Lock()
	defer f.mu.Unlock()
	msgs := f.messages[sessionID]
	if msgs == nil {
		msgs = []store.Message{}
	}
	return msgs, nil
}

func (f *fakeChatStore) ClearMessages(_ context.Context, sessionID string) error {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.messages[sessionID] = nil
	return nil
}

func (f *fakeChatStore) SearchMessages(_ context.Context, userID, query string, limit int) ([]store.Message, error) {
	f.mu.Lock()
	defer f.mu.Unlock()
	out := []store.Message{}
	for _, msgs := range f.messages {
		for _, m := range msgs {
			if strings.Contains(m.Content, query) {
				out = append(out, m)
			}
		}
	}
	return out, nil
}

func authReq(method, url, body string) *http.Request {
	var r *http.Request
	if body != "" {
		r, _ = http.NewRequest(method, url, strings.NewReader(body))
		r.Header.Set("Content-Type", "application/json")
	} else {
		r, _ = http.NewRequest(method, url, nil)
	}
	r.Header.Set("Authorization", "Bearer stub-token-admin")
	return r
}

func TestSessionLifecycle(t *testing.T) {
	auth := NewStubAuthManager()
	auth.Login("admin", "admin") // register stub-token-admin
	chat := newFakeChatStore()
	r := New(Dependencies{AuthMgr: auth, ChatStore: chat})
	srv := httptest.NewServer(r)
	defer srv.Close()

	// Create session
	resp, err := http.DefaultClient.Do(authReq("POST", srv.URL+"/api/v1/sessions", `{"title":""}`))
	if err != nil {
		t.Fatalf("POST sessions: %v", err)
	}
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("create: expected 201, got %d", resp.StatusCode)
	}
	var created struct {
		SessionID string `json:"session_id"`
	}
	readJSON(t, resp, &created)
	if created.SessionID == "" {
		t.Fatal("empty session_id")
	}

	// Seed messages directly
	chat.AddMessage(created.SessionID, "user", "今晚想吃火锅")
	chat.AddMessage(created.SessionID, "assistant", "好呀，要不要叫上朋友")

	// List sessions
	resp, _ = http.DefaultClient.Do(authReq("GET", srv.URL+"/api/v1/sessions", ""))
	var listed struct {
		Sessions []store.Session `json:"sessions"`
	}
	readJSON(t, resp, &listed)
	if len(listed.Sessions) != 1 {
		t.Fatalf("list: expected 1 session, got %d", len(listed.Sessions))
	}

	// Get messages
	resp, _ = http.DefaultClient.Do(authReq("GET", srv.URL+"/api/v1/sessions/"+created.SessionID+"/messages", ""))
	var msgs struct {
		Messages []store.Message `json:"messages"`
	}
	readJSON(t, resp, &msgs)
	if len(msgs.Messages) != 2 {
		t.Fatalf("messages: expected 2, got %d", len(msgs.Messages))
	}

	// Search
	resp, _ = http.DefaultClient.Do(authReq("GET", srv.URL+"/api/v1/messages/search?q=火锅", ""))
	var found struct {
		Total int `json:"total"`
	}
	readJSON(t, resp, &found)
	if found.Total != 1 {
		t.Errorf("search: expected 1 hit, got %d", found.Total)
	}

	// Export markdown
	resp, _ = http.DefaultClient.Do(authReq("GET", srv.URL+"/api/v1/sessions/"+created.SessionID+"/export", ""))
	body := readBody(t, resp)
	if !strings.Contains(body, "火锅") || !strings.Contains(body, "# Cyrene Chat") {
		t.Errorf("export markdown missing content: %q", body)
	}

	// Export json
	resp, _ = http.DefaultClient.Do(authReq("GET", srv.URL+"/api/v1/sessions/"+created.SessionID+"/export?format=json", ""))
	var exported struct {
		Messages []store.Message `json:"messages"`
	}
	readJSON(t, resp, &exported)
	if len(exported.Messages) != 2 {
		t.Errorf("export json: expected 2 messages, got %d", len(exported.Messages))
	}

	// Clear messages
	resp, _ = http.DefaultClient.Do(authReq("DELETE", srv.URL+"/api/v1/sessions/"+created.SessionID+"/messages", ""))
	if resp.StatusCode != http.StatusNoContent {
		t.Errorf("clear: expected 204, got %d", resp.StatusCode)
	}
	resp.Body.Close()

	// Delete session
	resp, _ = http.DefaultClient.Do(authReq("DELETE", srv.URL+"/api/v1/sessions/"+created.SessionID, ""))
	if resp.StatusCode != http.StatusNoContent {
		t.Errorf("delete: expected 204, got %d", resp.StatusCode)
	}
	resp.Body.Close()

	resp, _ = http.DefaultClient.Do(authReq("DELETE", srv.URL+"/api/v1/sessions/"+created.SessionID, ""))
	if resp.StatusCode != http.StatusNotFound {
		t.Errorf("delete again: expected 404, got %d", resp.StatusCode)
	}
	resp.Body.Close()
}

func TestSessionsUnavailableWithoutStore(t *testing.T) {
	auth := NewStubAuthManager()
	auth.Login("admin", "admin")
	r := New(Dependencies{AuthMgr: auth})
	srv := httptest.NewServer(r)
	defer srv.Close()

	resp, _ := http.DefaultClient.Do(authReq("GET", srv.URL+"/api/v1/sessions", ""))
	if resp.StatusCode != http.StatusServiceUnavailable {
		t.Errorf("expected 503 without store, got %d", resp.StatusCode)
	}
	resp.Body.Close()
}

func readJSON(t *testing.T, resp *http.Response, v any) {
	t.Helper()
	defer resp.Body.Close()
	if err := json.NewDecoder(resp.Body).Decode(v); err != nil {
		t.Fatalf("decode response: %v", err)
	}
}

func readBody(t *testing.T, resp *http.Response) string {
	t.Helper()
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatalf("read body: %v", err)
	}
	return string(b)
}