//
//  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

package handler

import (
	"errors"
	"fmt"
	"mime/multipart"
	"net/http"
	"strconv"
	"strings"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
	"gorm.io/gorm"

	"ragflow/internal/common"
	"ragflow/internal/entity"
	"ragflow/internal/service"
)

// AgentHandler agent handler
// fileUploader is the subset of FileService used by agent handlers.
type fileUploader interface {
	UploadFile(tenantID, parentID string, files []*multipart.FileHeader) ([]map[string]interface{}, error)
}

// AgentHandler agent handler
type AgentHandler struct {
	agentService *service.AgentService
	fileService  fileUploader
}

// NewAgentHandler create agent handler
func NewAgentHandler(agentService *service.AgentService, fileService *service.FileService) *AgentHandler {
	return &AgentHandler{agentService: agentService, fileService: fileService}
}

// ListAgents lists agent canvases for the current user.
// @Summary List Agents
// @Description List agent canvases accessible to the current user (Home dashboard tile)
// @Tags agents
// @Produce json
// @Param keywords query string false "Filter by title keyword"
// @Param page query int false "Page number (0 = no pagination)"
// @Param page_size query int false "Items per page (0 = no pagination)"
// @Param orderby query string false "Order-by field (default: create_time)"
// @Param desc query bool false "Descending order (default: true)"
// @Param owner_ids query string false "Comma-separated owner IDs to filter (default: all authorised tenants)"
// @Param canvas_category query string false "Canvas category (default: agent_canvas)"
// @Success 200 {object} service.ListAgentsResponse
// @Router /api/v1/agents [get]
func (h *AgentHandler) ListAgents(c *gin.Context) {
	user, errorCode, errorMessage := GetUser(c)
	if errorCode != common.CodeSuccess {
		jsonError(c, errorCode, errorMessage)
		return
	}

	keywords := c.Query("keywords")
	canvasCategory := c.Query("canvas_category")

	page := 0
	if v := c.Query("page"); v != "" {
		if p, err := strconv.Atoi(v); err == nil && p > 0 {
			page = p
		}
	}

	pageSize := 0
	if v := c.Query("page_size"); v != "" {
		if ps, err := strconv.Atoi(v); err == nil && ps > 0 {
			pageSize = ps
		}
	}

	orderby := c.DefaultQuery("orderby", "create_time")

	desc := true
	if v := c.Query("desc"); v != "" {
		desc = strings.ToLower(v) != "false"
	}

	var ownerIDs []string
	if raw := c.Query("owner_ids"); raw != "" {
		for _, id := range strings.Split(raw, ",") {
			id = strings.TrimSpace(id)
			if id != "" {
				ownerIDs = append(ownerIDs, id)
			}
		}
	}

	result, code, err := h.agentService.ListAgents(
		user.ID,
		keywords,
		page,
		pageSize,
		orderby,
		desc,
		ownerIDs,
		canvasCategory,
	)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code":    code,
			"data":    false,
			"message": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"code":    common.CodeSuccess,
		"data":    result,
		"message": "success",
	})
}

// ListAgentVersions returns versions for a specific agent.
// @Summary List Agent Versions
// @Description Returns all versions for a specific agent, ordered by update_time DESC.
// @Tags agents
// @Produce json
// @Param agent_id path string true "Agent ID"
// @Success 200 {object} map[string]interface{}
// @Router /api/v1/agents/{agent_id}/versions [get]
func (h *AgentHandler) ListAgentVersions(c *gin.Context) {
	user, errorCode, errorMessage := GetUser(c)
	if errorCode != common.CodeSuccess {
		jsonError(c, errorCode, errorMessage)
		return
	}

	agentID := c.Param("agent_id")
	if agentID == "" {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeArgumentError,
			"data":    nil,
			"message": "agent_id is required",
		})
		return
	}

	ok, err := h.agentService.CheckCanvasAccess(user.ID, agentID)
	if err != nil || !ok {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeOperatingError,
			"data":    nil,
			"message": "Agent not found or no permission.",
		})
		return
	}

	versions, err := h.agentService.ListVersions(agentID)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeServerError,
			"data":    nil,
			"message": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"code":    common.CodeSuccess,
		"data":    versions,
		"message": "",
	})
}

// ListTemplates lists every canvas template available to authenticated users.
// @Summary List Agent Templates
// @Description List the catalogue of canvas templates that authenticated users can clone.
// @Tags agents
// @Produce json
// @Security ApiKeyAuth
// @Success 200 {object} map[string]interface{}
// @Router /api/v1/agents/templates [get]
func (h *AgentHandler) ListTemplates(c *gin.Context) {
	if _, errorCode, errorMessage := GetUser(c); errorCode != common.CodeSuccess {
		jsonError(c, errorCode, errorMessage)
		return
	}

	templates, err := h.agentService.ListTemplates()
	if err != nil {
		jsonError(c, common.CodeServerError, err.Error())
		return
	}
	if templates == nil {
		// Ensure the JSON payload is always a list, never null.
		templates = []*entity.CanvasTemplate{}
	}

	c.JSON(http.StatusOK, gin.H{
		"code":    common.CodeSuccess,
		"data":    templates,
		"message": "success",
	})
}

// UploadAgentFile uploads one or more files associated with an agent.
// @Summary Upload Agent File
// @Description Upload one or more files for an agent canvas.

// GetAgentVersion returns a specific version for an agent.
// @Summary Get Agent Version
// @Description Returns a specific version by ID, verifying it belongs to the given agent.
// @Tags agents
// @Produce json
// @Param agent_id path string true "Agent ID"
// @Param version_id path string true "Version ID"
// @Success 200 {object} map[string]interface{}
// @Router /api/v1/agents/{agent_id}/versions/{version_id} [get]
func (h *AgentHandler) GetAgentVersion(c *gin.Context) {
	user, errorCode, errorMessage := GetUser(c)
	if errorCode != common.CodeSuccess {
		jsonError(c, errorCode, errorMessage)
		return
	}

	agentID := c.Param("agent_id")
	versionID := c.Param("version_id")
	if agentID == "" || versionID == "" {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeArgumentError,
			"data":    nil,
			"message": "agent_id and version_id are required",
		})
		return
	}

	ok, err := h.agentService.CheckCanvasAccess(user.ID, agentID)
	if err != nil || !ok {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeOperatingError,
			"data":    nil,
			"message": "Agent not found or no permission.",
		})
		return
	}

	version, err := h.agentService.GetVersion(agentID, versionID)
	if err != nil {
		isNotFound := errors.Is(err, gorm.ErrRecordNotFound) || err.Error() == "version not found"
		if !isNotFound {
			common.Warn("get agent version failed", zap.String("error", err.Error()))
			c.JSON(http.StatusOK, gin.H{
				"code":    common.CodeServerError,
				"data":    nil,
				"message": "Internal server error",
			})
			return
		}
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeNotFound,
			"data":    nil,
			"message": "Version not found.",
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"code":    common.CodeSuccess,
		"data":    version,
		"message": "",
	})
}

// @Tags agents
// @Accept multipart/form-data
// @Produce json
// @Param agent_id path string true "Agent ID"
// @Param file formData file true "File(s) to upload (multiple files supported)"
// @Success 200 {object} map[string]interface{}
// @Router /api/v1/agents/{agent_id}/upload [post]
func (h *AgentHandler) UploadAgentFile(c *gin.Context) {

	user, errorCode, errorMessage := GetUser(c)
	if errorCode != common.CodeSuccess {
		jsonError(c, errorCode, errorMessage)
		return
	}

	agentID := c.Param("agent_id")
	if agentID == "" {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeArgumentError,
			"data":    nil,
			"message": "agent_id is required",
		})
		return
	}

	ok, err := h.agentService.CheckCanvasAccess(user.ID, agentID)
	if err != nil || !ok {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeOperatingError,
			"data":    nil,
			"message": "Agent not found or no permission.",
		})
		return
	}

	form, err := c.MultipartForm()
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeArgumentError,
			"data":    nil,
			"message": fmt.Sprintf("invalid form data: %v", err),
		})
		return
	}

	files := form.File["file"]
	if len(files) == 0 {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeArgumentError,
			"data":    nil,
			"message": "You have to upload at least one file.",
		})
		return
	}

	// Use the canvas owner's tenant ID for file ownership.
	uploaded, err := h.fileService.UploadFile(user.ID, "", files)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code": common.CodeOperatingError,

			"data":    nil,
			"message": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"code": common.CodeSuccess,
		"data": uploaded,

		"message": "",
	})
}

type updateAgentTagsRequest struct {
	Tags interface{} `json:"tags"`
}

func (h *AgentHandler) UpdateAgentTags(c *gin.Context) {
	user, errorCode, errorMessage := GetUser(c)
	if errorCode != common.CodeSuccess {
		jsonError(c, errorCode, errorMessage)
		return
	}

	var req updateAgentTagsRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code":    common.CodeBadRequest,
			"data":    false,
			"message": err.Error(),
		})
		return
	}

	data, code, err := h.agentService.UpdateAgentTags(user.ID, c.Param("agent_id"), req.Tags)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"code":    code,
			"data":    false,
			"message": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"code":    common.CodeSuccess,
		"data":    data,
		"message": "success",
	})
}