package handler

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"io"
	"net/http"
	"path/filepath"
	"strings"

	"github.com/gin-gonic/gin"

	"github.com/sundynix/sundynix-shared/contract"
)

// KbIngest: POST /api/v1/kb/ingest —— 把文本入库到知识库（→ mcp-go kb_ingest → 切块/embedding/Milvus）。
// 供知识库管理页/脚本调用。
func (h *Handler) KbIngest(c *gin.Context) {
	var body struct {
		KB   string `json:"kb"`
		Text string `json:"text"`
	}
	if err := c.ShouldBindJSON(&body); err != nil || body.Text == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "text required"})
		return
	}
	res, err := h.bus.CallTool(c.Request.Context(), contract.ToolSubjectGo("kb_ingest"),
		&contract.ToolCall{Tool: "kb_ingest", Args: map[string]any{"kb": body.KB, "text": body.Text}})
	if err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	if !res.OK {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": res.Error})
		return
	}
	c.JSON(http.StatusOK, gin.H{"status": "ok", "message": res.Content})
}

// KbIngestFile: POST /api/v1/kb/ingest_file（multipart）—— 上传文件入库。
// 按类型路由：文本直读；docx/xlsx/pdf/csv → mcp-py parse_document 解析为文本 → kb_ingest。
func (h *Handler) KbIngestFile(c *gin.Context) {
	kb := c.PostForm("kb")
	fh, err := c.FormFile("file")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "file required"})
		return
	}
	f, err := fh.Open()
	if err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	defer f.Close()
	data, err := io.ReadAll(f)
	if err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	text, err := h.parseFile(c.Request.Context(), fh.Filename, data)
	if err != nil {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "解析失败: " + err.Error()})
		return
	}
	res, err := h.bus.CallTool(c.Request.Context(), contract.ToolSubjectGo("kb_ingest"),
		&contract.ToolCall{Tool: "kb_ingest", Args: map[string]any{"kb": kb, "text": text}})
	if err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	if !res.OK {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": res.Error})
		return
	}
	c.JSON(http.StatusOK, gin.H{"status": "ok", "file": fh.Filename, "chars": len([]rune(text)), "message": res.Content})
}

// parseFile 把文件字节转为纯文本：文本类直读，其余经 mcp-py parse_document（算法层）。
func (h *Handler) parseFile(ctx context.Context, filename string, data []byte) (string, error) {
	switch strings.ToLower(filepath.Ext(filename)) {
	case ".txt", ".md", ".markdown", ".text":
		return string(data), nil
	}
	res, err := h.bus.CallTool(ctx, contract.ToolSubjectPy("parse_document"),
		&contract.ToolCall{Tool: "parse_document", Args: map[string]any{
			"filename": filename, "content_b64": base64.StdEncoding.EncodeToString(data),
		}})
	if err != nil {
		return "", err
	}
	if res == nil || !res.OK {
		if res != nil && res.Error != "" {
			return "", errors.New(res.Error)
		}
		return "", errors.New("parse_document 无响应（mcp-py 未运行？）")
	}
	return res.Content, nil
}

// KbSearch: POST /api/v1/kb/search —— 检索台：查某知识库，返回带分数的命中（→ mcp-go kb_search）。
func (h *Handler) KbSearch(c *gin.Context) {
	var body struct {
		KB   string `json:"kb"`
		Q    string `json:"q"`
		TopK int    `json:"topK"`
	}
	if err := c.ShouldBindJSON(&body); err != nil || body.Q == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "q required"})
		return
	}
	args := map[string]any{"kb": body.KB, "q": body.Q}
	if body.TopK > 0 {
		args["topK"] = body.TopK
	}
	res, err := h.bus.CallTool(c.Request.Context(), contract.ToolSubjectGo("kb_search"),
		&contract.ToolCall{Tool: "kb_search", Args: args})
	if err != nil {
		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
		return
	}
	if !res.OK {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": res.Error})
		return
	}
	var hits []map[string]any
	_ = json.Unmarshal([]byte(res.Content), &hits)
	c.JSON(http.StatusOK, gin.H{"hits": hits})
}