package handler

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

	"github.com/gin-gonic/gin"

	"github.com/sundynix/sundynix-gateway/internal/store"
	"github.com/sundynix/sundynix-shared/contract"
	"github.com/sundynix/sundynix-shared/prompts"
	"github.com/sundynix/sundynix-shared/secrets"
)

// AdminOverview: GET /api/v1/admin/overview —— 管理端系统级聚合（控制塔口径）。
// 区别于 stats/overview（桌面端个人工作台）：这里一律系统级——全平台用户/任务/评测/
// 模型配置态/提示词控制面态/服务健康。Task/Eval 表无 owner 即全量；用户/KB/Doc 走全局计数。
func (h *Handler) AdminOverview(c *gin.Context) {
	ctx := c.Request.Context()

	ov := h.db.StatsOverview(ctx, "") // owner="" → 跳过个人 KB 口径，仅取全局任务/评测
	users, kbs, docs := h.db.SystemCounts(ctx)

	// 模型配置态：主模型 + 备用链数 + 各 kind 数量。
	chat, _ := h.db.ListModels(ctx, "chat")
	emb, _ := h.db.ListModels(ctx, "embedding")
	activeChat, activeEmb, fallbacks := "", "", 0
	for _, m := range chat {
		if m.Active {
			activeChat = m.Provider + "/" + m.Model
		} else {
			fallbacks++
		}
	}
	for _, m := range emb {
		if m.Active {
			activeEmb = m.Provider + "/" + m.Model
		}
	}

	// 提示词控制面态：受管 key 总数（代码内置）vs 已激活热覆盖数。
	promptRows, _ := h.db.ListPrompts(ctx)
	overrides := map[string]struct{}{}
	for _, pr := range promptRows {
		if pr.Active {
			overrides[pr.Key] = struct{}{}
		}
	}

	// 服务健康（与 Health / StatsOverview 同口径：本地可判 + milvus/neo4j 经 mcp-go）。
	services := gin.H{"gateway": true, "nats": true, "db": h.db.Enabled(), "redis": h.cache.Enabled(), "milvus": false, "neo4j": false}
	cctx, cancel := context.WithTimeout(ctx, 2*time.Second)
	defer cancel()
	if res, err := h.bus.CallTool(cctx, contract.ToolSubjectGo("health"), &contract.ToolCall{Tool: "health"}); err == nil && res != nil && res.OK {
		var sub map[string]bool
		if json.Unmarshal([]byte(res.Content), &sub) == nil {
			services["milvus"], services["neo4j"] = sub["milvus"], sub["neo4j"]
		}
	}

	c.JSON(http.StatusOK, gin.H{
		"users": users, "kb_count": kbs, "kb_docs": docs,
		"tasks_today": ov.TasksToday, "tasks_total": ov.TasksTotal,
		"status_count": ov.StatusCount, "task_trend": ov.TaskTrend,
		"eval_avg": ov.EvalAvg, "faithful_avg": ov.FaithfulAvg, "eval_count": ov.EvalCount,
		"models": gin.H{
			"chat_count": len(chat), "embedding_count": len(emb),
			"active_chat": activeChat, "active_embedding": activeEmb, "fallbacks": fallbacks,
		},
		"prompts":    gin.H{"managed": len(prompts.Known), "overrides": len(overrides)},
		"services":   services,
		"checked_at": time.Now().Format(time.RFC3339),
	})
}

// maskPrefix 是脱敏展示用的占位前缀；前端把列表里的脱敏 key 原样回传即视为「未改动」。
const maskPrefix = "••••"

// existingModelKey 取某 id 模型库内存储的 api_key（密文，未解密）；不存在返回空。
func (h *Handler) existingModelKey(ctx context.Context, id string) string {
	if id == "" {
		return ""
	}
	rows, _ := h.db.ListModels(ctx, "")
	for _, m := range rows {
		if m.ID == id {
			return m.APIKey
		}
	}
	return ""
}

// 控制面（运维管理）：LLM 模型配置 CRUD + 测试连接 + 变更广播。
// 表 sundynix_model 由 Gateway 持有；Dispatcher 经 NATS 取激活配置。

type modelBody struct {
	ID       string `json:"id"`
	Kind     string `json:"kind"`
	Provider string `json:"provider"`
	BaseURL  string `json:"base_url"`
	APIKey   string `json:"api_key"`
	Model    string `json:"model"`
}

// ListModels: GET /api/v1/admin/models?kind=chat|embedding —— 列出模型（api_key 脱敏）。
func (h *Handler) ListModels(c *gin.Context) {
	rows, err := h.db.ListModels(c.Request.Context(), c.Query("kind"))
	if err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	out := make([]gin.H, 0, len(rows))
	for _, m := range rows {
		plain, _ := secrets.Decrypt(m.APIKey) // 库内为密文，脱敏前先还原以展示真实尾 4 位
		out = append(out, gin.H{
			"id": m.ID, "kind": m.Kind, "provider": m.Provider, "base_url": m.BaseURL,
			"model": m.Model, "active": m.Active, "api_key": mask(plain),
		})
	}
	c.JSON(http.StatusOK, gin.H{"models": out})
}

// ListPricing: GET /api/v1/admin/pricing —— 列出各模型的计价配置（token↔真钱）。
func (h *Handler) ListPricing(c *gin.Context) {
	rows, err := h.db.ListPricing(c.Request.Context())
	if err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	out := make([]gin.H, 0, len(rows))
	for _, p := range rows {
		out = append(out, gin.H{
			"model_id": p.ModelID, "input_per_1k": p.InputPer1K, "output_per_1k": p.OutputPer1K, "currency": p.Currency,
		})
	}
	c.JSON(http.StatusOK, gin.H{"pricing": out})
}

// SavePricing: PUT /api/v1/admin/pricing —— 设置某模型的输入/输出单价（每 1K token）。
func (h *Handler) SavePricing(c *gin.Context) {
	var b struct {
		ModelID     string  `json:"model_id"`
		InputPer1K  float64 `json:"input_per_1k"`
		OutputPer1K float64 `json:"output_per_1k"`
		Currency    string  `json:"currency"`
	}
	if err := c.ShouldBindJSON(&b); err != nil || b.ModelID == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "model_id required"})
		return
	}
	if b.InputPer1K < 0 || b.OutputPer1K < 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "单价不能为负"})
		return
	}
	if b.Currency == "" {
		b.Currency = "CNY"
	}
	if err := h.db.UpsertPricing(c.Request.Context(), b.ModelID, b.InputPer1K, b.OutputPer1K, b.Currency); err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"status": "ok"})
}

// SaveModel: POST /api/v1/admin/models —— 新增/更新一条模型配置。
func (h *Handler) SaveModel(c *gin.Context) {
	var b modelBody
	if err := c.ShouldBindJSON(&b); err != nil || b.BaseURL == "" || b.Model == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "provider/base_url/model required"})
		return
	}
	provider := b.Provider
	if provider == "" {
		provider = "openai-compatible"
	}
	kind := b.Kind
	if kind == "" {
		kind = contract.ConfigKindChat
	}
	// api_key 处理：空或脱敏占位 => 沿用库内既有密文（更新时未改 key）；否则视为新明文，加密落库。
	apiKey := b.APIKey
	if apiKey == "" || strings.HasPrefix(apiKey, maskPrefix) {
		apiKey = h.existingModelKey(c.Request.Context(), b.ID) // 已是密文，原样保留（不存在则空）
	} else {
		enc, err := secrets.Encrypt(apiKey)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "encrypt api_key: " + err.Error()})
			return
		}
		apiKey = enc
	}
	m := &store.LLMModel{BaseModel: store.BaseModel{ID: b.ID}, Kind: kind, Provider: provider, BaseURL: b.BaseURL, APIKey: apiKey, Model: b.Model}
	if err := h.db.SaveModel(c.Request.Context(), m); err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	h.broadcastActive(c.Request.Context())
	c.JSON(http.StatusOK, gin.H{"id": m.ID})
}

// SetActiveModel: POST /api/v1/admin/models/:id/active —— 设为激活并广播。
func (h *Handler) SetActiveModel(c *gin.Context) {
	id := c.Param("id")
	if err := h.db.SetActiveModel(c.Request.Context(), id); err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	h.broadcastActive(c.Request.Context())
	c.JSON(http.StatusOK, gin.H{"status": "ok", "active": id})
}

// DeleteModel: DELETE /api/v1/admin/models/:id
func (h *Handler) DeleteModel(c *gin.Context) {
	id := c.Param("id")
	if err := h.db.DeleteModel(c.Request.Context(), id); err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	h.broadcastActive(c.Request.Context())
	c.JSON(http.StatusOK, gin.H{"status": "ok"})
}

// TestModel: POST /api/v1/admin/models/test —— 探测 OpenAI 兼容端点连通性。
func (h *Handler) TestModel(c *gin.Context) {
	var b modelBody
	if err := c.ShouldBindJSON(&b); err != nil || b.BaseURL == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "base_url required"})
		return
	}
	// 若未带 key（或回传脱敏占位），用库里的真实 key。
	key := b.APIKey
	if key == "" || strings.HasPrefix(key, maskPrefix) {
		key = h.existingModelKey(c.Request.Context(), b.ID)
	}
	// key 此刻可能是库内密文，也可能是用户新填的明文；Decrypt 对无前缀明文透传，两种都还原成可用明文。
	if plain, err := secrets.Decrypt(key); err == nil {
		key = plain
	}
	ctx, cancel := context.WithTimeout(c.Request.Context(), 10*time.Second)
	defer cancel()
	var req *http.Request
	if b.Kind == contract.ConfigKindEmbedding {
		// embedding 端点多无 /models，发一个最小 /embeddings 探测。
		payload, _ := json.Marshal(map[string]any{"model": b.Model, "input": []string{"ping"}})
		req, _ = http.NewRequestWithContext(ctx, http.MethodPost, b.BaseURL+"/embeddings", bytes.NewReader(payload))
		req.Header.Set("Content-Type", "application/json")
	} else {
		req, _ = http.NewRequestWithContext(ctx, http.MethodGet, b.BaseURL+"/models", nil)
	}
	if key != "" {
		req.Header.Set("Authorization", "Bearer "+key)
	}
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"ok": false, "message": err.Error()})
		return
	}
	defer resp.Body.Close()
	c.JSON(http.StatusOK, gin.H{"ok": resp.StatusCode < 400, "message": "HTTP " + resp.Status})
}

// broadcastActive 重新广播各 kind 当前激活配置，触发对应消费方热更新。
// chat 配置带 Fallbacks（其它已登记 chat 模型作备用），dispatcher 据此重建 failover 链。
func (h *Handler) broadcastActive(ctx context.Context) {
	for _, kind := range []string{contract.ConfigKindChat, contract.ConfigKindEmbedding} {
		if cfg := h.db.ActiveConfig(ctx, kind); cfg != nil {
			_ = h.bus.PublishConfigUpdated(kind, cfg)
		}
	}
}

func mask(s string) string {
	if len(s) <= 4 {
		if s == "" {
			return ""
		}
		return "••••"
	}
	return "••••" + s[len(s)-4:]
}