package handler

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

	"github.com/gin-gonic/gin"

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

// 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 {
		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(m.APIKey),
		})
	}
	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
	}
	m := &store.LLMModel{BaseModel: store.BaseModel{ID: b.ID}, Kind: kind, Provider: provider, BaseURL: b.BaseURL, APIKey: b.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
	}
	// 若传了已存的 id 但未带 key，用库里的真实 key。
	key := b.APIKey
	if key == "" && b.ID != "" {
		if rows, _ := h.db.ListModels(c.Request.Context(), ""); rows != nil {
			for _, m := range rows {
				if m.ID == b.ID {
					key = m.APIKey
				}
			}
		}
	}
	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。
func (h *Handler) broadcastActive(ctx context.Context) {
	for _, kind := range []string{contract.ConfigKindChat, contract.ConfigKindEmbedding} {
		row, _ := h.db.GetActiveModel(ctx, kind)
		if row == nil {
			continue
		}
		_ = h.bus.PublishConfigUpdated(kind, &contract.ModelConfig{
			Provider: row.Provider, BaseURL: row.BaseURL, APIKey: row.APIKey, Model: row.Model,
		})
	}
}

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