package webui

import (
	"bytes"
	"context"
	"encoding/json"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"laodingbot/internal/config"
	"laodingbot/internal/llm"
)

func newTestBot(t *testing.T, maxUploadBytes int64) *Bot {
	t.Helper()
	b, err := NewBot(config.WebUIConfig{ListenAddr: ":8090", MaxUploadBytes: maxUploadBytes}, nil)
	if err != nil {
		t.Fatalf("NewBot failed: %v", err)
	}
	return b
}

func TestHandleChatSuccess(t *testing.T) {
	b := newTestBot(t, 1024*1024)
	b.chatHandler = func(_ context.Context, msg IncomingMessage) (string, error) {
		if msg.ChatID != "s1" || msg.UserID != "u1" || msg.Text != "hello" {
			t.Fatalf("unexpected message: %+v", msg)
		}
		return "ok", nil
	}

	body := strings.NewReader(`{"text":"hello","session_id":"s1","user_id":"u1"}`)
	req := httptest.NewRequest(http.MethodPost, "/api/chat", body)
	req.Header.Set("Content-Type", "application/json")
	w := httptest.NewRecorder()

	b.handleChat(w, req)
	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d body=%s", w.Code, w.Body.String())
	}

	var out chatResponse
	if err := json.Unmarshal(w.Body.Bytes(), &out); err != nil {
		t.Fatalf("decode response failed: %v", err)
	}
	if out.Reply != "ok" || out.SessionID != "s1" || out.UserID != "u1" {
		t.Fatalf("unexpected response: %+v", out)
	}
}

func TestHandleChatMissingText(t *testing.T) {
	b := newTestBot(t, 1024*1024)
	b.chatHandler = func(_ context.Context, _ IncomingMessage) (string, error) { return "", nil }

	body := strings.NewReader(`{"text":"   "}`)
	req := httptest.NewRequest(http.MethodPost, "/api/chat", body)
	req.Header.Set("Content-Type", "application/json")
	w := httptest.NewRecorder()

	b.handleChat(w, req)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("expected 400, got %d", w.Code)
	}
}

func TestHandleUploadSuccess(t *testing.T) {
	b := newTestBot(t, 1024*1024)
	b.uploadHandler = func(_ context.Context, chatID, userID string, files []llm.InputFile) ([]string, error) {
		if chatID != "s1" || userID != "u1" {
			t.Fatalf("unexpected ids chat=%s user=%s", chatID, userID)
		}
		if len(files) != 1 {
			t.Fatalf("unexpected files len=%d", len(files))
		}
		if files[0].FileName != "doc.pdf" || len(files[0].Content) == 0 {
			t.Fatalf("unexpected file payload: %+v", files[0])
		}
		return []string{"file_123"}, nil
	}

	var payload bytes.Buffer
	writer := multipart.NewWriter(&payload)
	_ = writer.WriteField("session_id", "s1")
	_ = writer.WriteField("user_id", "u1")
	fw, err := writer.CreateFormFile("file", "doc.pdf")
	if err != nil {
		t.Fatalf("CreateFormFile failed: %v", err)
	}
	_, _ = fw.Write([]byte("pdf-content"))
	_ = writer.Close()

	req := httptest.NewRequest(http.MethodPost, "/api/upload", &payload)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	w := httptest.NewRecorder()

	b.handleUpload(w, req)
	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d body=%s", w.Code, w.Body.String())
	}

	var out uploadResponse
	if err := json.Unmarshal(w.Body.Bytes(), &out); err != nil {
		t.Fatalf("decode response failed: %v", err)
	}
	if out.FileID != "file_123" || out.SessionID != "s1" || out.UserID != "u1" {
		t.Fatalf("unexpected response: %+v", out)
	}
}

func TestHandleUploadTooLarge(t *testing.T) {
	b := newTestBot(t, 3)
	b.uploadHandler = func(_ context.Context, _ string, _ string, _ []llm.InputFile) ([]string, error) {
		return []string{"file_should_not_reach"}, nil
	}

	var payload bytes.Buffer
	writer := multipart.NewWriter(&payload)
	fw, err := writer.CreateFormFile("file", "a.txt")
	if err != nil {
		t.Fatalf("CreateFormFile failed: %v", err)
	}
	_, _ = fw.Write([]byte("12345"))
	_ = writer.Close()

	req := httptest.NewRequest(http.MethodPost, "/api/upload", &payload)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	w := httptest.NewRecorder()

	b.handleUpload(w, req)
	if w.Code != http.StatusRequestEntityTooLarge {
		t.Fatalf("expected 413, got %d body=%s", w.Code, w.Body.String())
	}
}

func TestHandleUploadMissingFile(t *testing.T) {
	b := newTestBot(t, 1024*1024)
	b.uploadHandler = func(_ context.Context, _ string, _ string, _ []llm.InputFile) ([]string, error) {
		return []string{"file_should_not_reach"}, nil
	}

	var payload bytes.Buffer
	writer := multipart.NewWriter(&payload)
	_ = writer.WriteField("session_id", "s1")
	_ = writer.Close()

	req := httptest.NewRequest(http.MethodPost, "/api/upload", &payload)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	w := httptest.NewRecorder()

	b.handleUpload(w, req)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("expected 400, got %d", w.Code)
	}
}