package admin

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

	"github.com/go-chi/chi/v5"

	authn "ds2api/internal/auth"
	"ds2api/internal/config"
	"ds2api/internal/sse"
)

func (h *Handler) listAccounts(w http.ResponseWriter, r *http.Request) {
	page := intFromQuery(r, "page", 1)
	pageSize := intFromQuery(r, "page_size", 10)
	if page < 1 {
		page = 1
	}
	if pageSize < 1 {
		pageSize = 1
	}
	if pageSize > 100 {
		pageSize = 100
	}
	accounts := h.Store.Snapshot().Accounts
	total := len(accounts)
	reverseAccounts(accounts)
	totalPages := 1
	if total > 0 {
		totalPages = (total + pageSize - 1) / pageSize
	}
	start := (page - 1) * pageSize
	if start > total {
		start = total
	}
	end := start + pageSize
	if end > total {
		end = total
	}
	items := make([]map[string]any, 0, end-start)
	for _, acc := range accounts[start:end] {
		token := strings.TrimSpace(acc.Token)
		preview := ""
		if token != "" {
			if len(token) > 20 {
				preview = token[:20] + "..."
			} else {
				preview = token
			}
		}
		items = append(items, map[string]any{"email": acc.Email, "mobile": acc.Mobile, "has_password": acc.Password != "", "has_token": token != "", "token_preview": preview})
	}
	writeJSON(w, http.StatusOK, map[string]any{"items": items, "total": total, "page": page, "page_size": pageSize, "total_pages": totalPages})
}

func (h *Handler) addAccount(w http.ResponseWriter, r *http.Request) {
	var req map[string]any
	_ = json.NewDecoder(r.Body).Decode(&req)
	acc := toAccount(req)
	if acc.Identifier() == "" {
		writeJSON(w, http.StatusBadRequest, map[string]any{"detail": "需要 email 或 mobile"})
		return
	}
	err := h.Store.Update(func(c *config.Config) error {
		for _, a := range c.Accounts {
			if acc.Email != "" && a.Email == acc.Email {
				return fmt.Errorf("邮箱已存在")
			}
			if acc.Mobile != "" && a.Mobile == acc.Mobile {
				return fmt.Errorf("手机号已存在")
			}
		}
		c.Accounts = append(c.Accounts, acc)
		return nil
	})
	if err != nil {
		writeJSON(w, http.StatusBadRequest, map[string]any{"detail": err.Error()})
		return
	}
	h.Pool.Reset()
	writeJSON(w, http.StatusOK, map[string]any{"success": true, "total_accounts": len(h.Store.Snapshot().Accounts)})
}

func (h *Handler) deleteAccount(w http.ResponseWriter, r *http.Request) {
	identifier := chi.URLParam(r, "identifier")
	err := h.Store.Update(func(c *config.Config) error {
		idx := -1
		for i, a := range c.Accounts {
			if a.Email == identifier || a.Mobile == identifier {
				idx = i
				break
			}
		}
		if idx < 0 {
			return fmt.Errorf("账号不存在")
		}
		c.Accounts = append(c.Accounts[:idx], c.Accounts[idx+1:]...)
		return nil
	})
	if err != nil {
		writeJSON(w, http.StatusNotFound, map[string]any{"detail": err.Error()})
		return
	}
	h.Pool.Reset()
	writeJSON(w, http.StatusOK, map[string]any{"success": true, "total_accounts": len(h.Store.Snapshot().Accounts)})
}

func (h *Handler) queueStatus(w http.ResponseWriter, _ *http.Request) {
	writeJSON(w, http.StatusOK, h.Pool.Status())
}

func (h *Handler) testSingleAccount(w http.ResponseWriter, r *http.Request) {
	var req map[string]any
	_ = json.NewDecoder(r.Body).Decode(&req)
	identifier, _ := req["identifier"].(string)
	if strings.TrimSpace(identifier) == "" {
		writeJSON(w, http.StatusBadRequest, map[string]any{"detail": "需要账号标识（email 或 mobile）"})
		return
	}
	acc, ok := h.Store.FindAccount(identifier)
	if !ok {
		writeJSON(w, http.StatusNotFound, map[string]any{"detail": "账号不存在"})
		return
	}
	model, _ := req["model"].(string)
	if model == "" {
		model = "deepseek-chat"
	}
	message, _ := req["message"].(string)
	result := h.testAccount(r.Context(), acc, model, message)
	writeJSON(w, http.StatusOK, result)
}

func (h *Handler) testAllAccounts(w http.ResponseWriter, r *http.Request) {
	var req map[string]any
	_ = json.NewDecoder(r.Body).Decode(&req)
	model, _ := req["model"].(string)
	if model == "" {
		model = "deepseek-chat"
	}
	accounts := h.Store.Snapshot().Accounts
	if len(accounts) == 0 {
		writeJSON(w, http.StatusOK, map[string]any{"total": 0, "success": 0, "failed": 0, "results": []any{}})
		return
	}

	// Concurrent testing with a semaphore to limit parallelism.
	const maxConcurrency = 5
	results := runAccountTestsConcurrently(accounts, maxConcurrency, func(_ int, account config.Account) map[string]any {
		return h.testAccount(r.Context(), account, model, "")
	})

	success := 0
	for _, res := range results {
		if ok, _ := res["success"].(bool); ok {
			success++
		}
	}
	writeJSON(w, http.StatusOK, map[string]any{"total": len(accounts), "success": success, "failed": len(accounts) - success, "results": results})
}

func runAccountTestsConcurrently(accounts []config.Account, maxConcurrency int, testFn func(int, config.Account) map[string]any) []map[string]any {
	if maxConcurrency <= 0 {
		maxConcurrency = 1
	}
	sem := make(chan struct{}, maxConcurrency)
	results := make([]map[string]any, len(accounts))
	var wg sync.WaitGroup
	for i, acc := range accounts {
		wg.Add(1)
		go func(idx int, account config.Account) {
			defer wg.Done()
			sem <- struct{}{}        // acquire
			defer func() { <-sem }() // release
			results[idx] = testFn(idx, account)
		}(i, acc)
	}
	wg.Wait()
	return results
}

func (h *Handler) testAccount(ctx context.Context, acc config.Account, model, message string) map[string]any {
	start := time.Now()
	result := map[string]any{"account": acc.Identifier(), "success": false, "response_time": 0, "message": "", "model": model}
	token := strings.TrimSpace(acc.Token)
	if token == "" {
		newToken, err := h.DS.Login(ctx, acc)
		if err != nil {
			result["message"] = "登录失败: " + err.Error()
			return result
		}
		token = newToken
		_ = h.Store.UpdateAccountToken(acc.Identifier(), token)
	}
	authCtx := &authn.RequestAuth{UseConfigToken: false, DeepSeekToken: token}
	sessionID, err := h.DS.CreateSession(ctx, authCtx, 1)
	if err != nil {
		newToken, loginErr := h.DS.Login(ctx, acc)
		if loginErr != nil {
			result["message"] = "创建会话失败: " + err.Error()
			return result
		}
		token = newToken
		authCtx.DeepSeekToken = token
		_ = h.Store.UpdateAccountToken(acc.Identifier(), token)
		sessionID, err = h.DS.CreateSession(ctx, authCtx, 1)
		if err != nil {
			result["message"] = "创建会话失败: " + err.Error()
			return result
		}
	}
	if strings.TrimSpace(message) == "" {
		result["success"] = true
		result["message"] = "API 测试成功（仅会话创建）"
		result["response_time"] = int(time.Since(start).Milliseconds())
		return result
	}
	thinking, search, ok := config.GetModelConfig(model)
	if !ok {
		thinking, search = false, false
	}
	_ = search
	pow, err := h.DS.GetPow(ctx, authCtx, 1)
	if err != nil {
		result["message"] = "获取 PoW 失败: " + err.Error()
		return result
	}
	payload := map[string]any{"chat_session_id": sessionID, "prompt": "<｜User｜>" + message, "ref_file_ids": []any{}, "thinking_enabled": thinking, "search_enabled": search}
	resp, err := h.DS.CallCompletion(ctx, authCtx, payload, pow, 1)
	if err != nil {
		result["message"] = "请求失败: " + err.Error()
		return result
	}
	if resp.StatusCode != http.StatusOK {
		defer resp.Body.Close()
		result["message"] = fmt.Sprintf("请求失败: HTTP %d", resp.StatusCode)
		return result
	}
	collected := sse.CollectStream(resp, thinking, true)
	result["success"] = true
	result["response_time"] = int(time.Since(start).Milliseconds())
	if collected.Text != "" {
		result["message"] = collected.Text
	} else {
		result["message"] = "（无回复内容）"
	}
	if collected.Thinking != "" {
		result["thinking"] = collected.Thinking
	}
	return result
}

func (h *Handler) testAPI(w http.ResponseWriter, r *http.Request) {
	var req map[string]any
	_ = json.NewDecoder(r.Body).Decode(&req)
	model, _ := req["model"].(string)
	message, _ := req["message"].(string)
	apiKey, _ := req["api_key"].(string)
	if model == "" {
		model = "deepseek-chat"
	}
	if message == "" {
		message = "你好"
	}
	if apiKey == "" {
		keys := h.Store.Snapshot().Keys
		if len(keys) == 0 {
			writeJSON(w, http.StatusBadRequest, map[string]any{"detail": "没有可用的 API Key"})
			return
		}
		apiKey = keys[0]
	}
	host := r.Host
	scheme := "http"
	if strings.Contains(strings.ToLower(host), "vercel") || strings.Contains(strings.ToLower(r.Header.Get("X-Forwarded-Proto")), "https") {
		scheme = "https"
	}
	payload := map[string]any{"model": model, "messages": []map[string]any{{"role": "user", "content": message}}, "stream": false}
	b, _ := json.Marshal(payload)
	request, _ := http.NewRequestWithContext(r.Context(), http.MethodPost, fmt.Sprintf("%s://%s/v1/chat/completions", scheme, host), bytes.NewReader(b))
	request.Header.Set("Authorization", "Bearer "+apiKey)
	request.Header.Set("Content-Type", "application/json")
	resp, err := (&http.Client{Timeout: 60 * time.Second}).Do(request)
	if err != nil {
		writeJSON(w, http.StatusOK, map[string]any{"success": false, "error": err.Error()})
		return
	}
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	if resp.StatusCode == http.StatusOK {
		var parsed any
		_ = json.Unmarshal(body, &parsed)
		writeJSON(w, http.StatusOK, map[string]any{"success": true, "status_code": resp.StatusCode, "response": parsed})
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"success": false, "status_code": resp.StatusCode, "response": string(body)})
}