package controller

import (
	"encoding/json"
	"net/http"
	"strconv"
	"time"

	"ezops/model"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

type flowStep struct {
	Name         string `json:"name"`
	ApproverRole string `json:"approver_role"`
	StepType     string `json:"step_type"` // audit, execute
}

// ListProcesses 获取审批流程列表 // Logan.Li
func (h *ApprovalHandler) ListProcesses(c *gin.Context) {
	var query model.PageQuery
	c.ShouldBindQuery(&query)

	db := h.db.Model(&model.ApprovalProcess{}).
		Preload("Template").
		Preload("ApplicantUser").
		Preload("Steps", func(db *gorm.DB) *gorm.DB {
			return db.Order("step ASC")
		})

	if status := c.Query("status"); status != "" {
		db = db.Where("status = ?", status)
	}
	if category := c.Query("category"); category != "" {
		db = db.Joins("JOIN sys_approval_templates ON sys_approval_templates.id = approval_processes.template_id").
			Where("sys_approval_templates.category = ?", category)
	}

	var total int64
	db.Count(&total)

	var processes []model.ApprovalProcess
	db.Order("created_at DESC").Offset(query.GetOffset()).Limit(query.GetLimit()).Find(&processes)

	// Preload approver user for each step
	for i := range processes {
		for j := range processes[i].Steps {
			h.db.Preload("ApproverUser").First(&processes[i].Steps[j], processes[i].Steps[j].ID)
		}
	}

	c.JSON(http.StatusOK, model.Response{
		Code:    200,
		Message: "success",
		Data: model.ListResponse{
			List:  processes,
			Total: total,
		},
	})
}

// GetProcess 获取审批流程详情 // Logan.Li
func (h *ApprovalHandler) GetProcess(c *gin.Context) {
	id, _ := strconv.Atoi(c.Param("id"))

	var process model.ApprovalProcess
	if err := h.db.Preload("Template").Preload("ApplicantUser").
		Preload("Steps.ApproverUser").Preload("Steps", func(db *gorm.DB) *gorm.DB {
		return db.Order("step ASC")
	}).First(&process, id).Error; err != nil {
		c.JSON(http.StatusNotFound, model.Response{
			Code:    404,
			Message: "流程不存在",
		})
		return
	}

	c.JSON(http.StatusOK, model.Response{
		Code:    200,
		Message: "success",
		Data:    process,
	})
}

// CreateProcess 创建审批流程 — 使用审批流程配置 (sys_approval_workflows) // Logan.Li
func (h *ApprovalHandler) CreateProcess(c *gin.Context) {
	var req model.CreateApprovalProcessRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, model.Response{
			Code:    400,
			Message: "请求参数错误: " + err.Error(),
		})
		return
	}

	userIDVal, _ := c.Get("userID")
	userID := toUint(userIDVal)

	var template model.ApprovalTemplate
	if err := h.db.First(&template, req.TemplateID).Error; err != nil {
		c.JSON(http.StatusNotFound, model.Response{Code: 404, Message: "模板不存在"})
		return
	}

	// 查找该分类下的默认/活跃审批流程配置
	var workflow model.ApprovalWorkflow
	if err := h.db.Where("category = ? AND is_active = ?", template.Category, true).
		Order("is_default DESC").First(&workflow).Error; err != nil {
		// 无工作流配置，回退到模板 flow_config
	}
	// 获取工作流步骤（跳过 submit 类型）
	var workflowSteps []model.ApprovalWorkflowStep
	stepCount := 1
	var approvalSteps []struct {
		name        string
		stepType    string
		approverIDs []uint
	}
	if workflow.ID > 0 {
		h.db.Where("workflow_id = ?", workflow.ID).Order("step_number ASC").Find(&workflowSteps)
		for _, ws := range workflowSteps {
			if ws.StepType == "submit" {
				continue // 提交步骤由申请人完成，不生成审批节点
			}
			stepCount++
			approvalSteps = append(approvalSteps, struct {
				name        string
				stepType    string
				approverIDs []uint
			}{ws.Name, ws.StepType, ParseApproverIDs(ws.ApproverIDs)})
		}
	}
	totalSteps := len(approvalSteps)
	if totalSteps == 0 {
		totalSteps = 1
	}

	process := model.ApprovalProcess{
		TemplateID:  req.TemplateID,
		Title:       req.Title,
		Applicant:   userID,
		FormData:    req.FormData,
		Status:      "pending",
		CurrentStep: 1,
		TotalSteps:  totalSteps,
	}

	tx := h.db.Begin()
	if err := tx.Create(&process).Error; err != nil {
		tx.Rollback()
		c.JSON(http.StatusInternalServerError, model.Response{Code: 500, Message: "创建失败: " + err.Error()})
		return
	}

	// 创建审批步骤（仅 audit + execute）
	for i, as := range approvalSteps {
		stepType := as.stepType
		if stepType == "" {
			// 最后一步默认执行，其余审核
			if i == len(approvalSteps)-1 {
				stepType = "execute"
			} else {
				stepType = "audit"
			}
		}
		approverID := uint(1) // 默认管理员
		if len(as.approverIDs) > 0 {
			approverID = as.approverIDs[0]
		}
		step := model.ApprovalStep{
			ProcessID: process.ID,
			Step:      i + 1,
			StepType:  stepType,
			Approver:  approverID,
			Status:    "pending",
			Comment:   as.name, // 存步骤名称
		}
		if err := tx.Create(&step).Error; err != nil {
			tx.Rollback()
			c.JSON(http.StatusInternalServerError, model.Response{Code: 500, Message: "创建步骤失败"})
			return
		}
	}

	tx.Commit()

	// 重新加载完整数据
	h.db.Preload("Template").Preload("ApplicantUser").Preload("Steps.ApproverUser").First(&process, process.ID)

	c.JSON(http.StatusOK, model.Response{
		Code:    200,
		Message: "申请已提交",
		Data:    process,
	})
}

// ParseApproverIDs 解析审批人JSON数组
func ParseApproverIDs(raw string) []uint {
	if raw == "" {
		return nil
	}
	var ids []uint
	if err := json.Unmarshal([]byte(raw), &ids); err != nil {
		return nil
	}
	return ids
}

func toUint(v interface{}) uint {
	switch val := v.(type) {
	case float64:
		return uint(val)
	case uint:
		return val
	case int:
		return uint(val)
	default:
		return 0
	}
}

// ApproveProcess 审批通过 // Logan.Li
func (h *ApprovalHandler) ApproveProcess(c *gin.Context) {
	id, _ := strconv.Atoi(c.Param("id"))

	var req model.ApproveRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, model.Response{Code: 400, Message: "请求参数错误"})
		return
	}

	userIDVal, _ := c.Get("userID")
	approverID := toUint(userIDVal)

	var process model.ApprovalProcess
	if err := h.db.First(&process, id).Error; err != nil {
		c.JSON(http.StatusNotFound, model.Response{Code: 404, Message: "流程不存在"})
		return
	}

	if process.Status != "pending" {
		c.JSON(http.StatusBadRequest, model.Response{Code: 400, Message: "该申请已处理"})
		return
	}

	now := time.Now()

	// 查找当前步骤
	var currentStep model.ApprovalStep
	if err := h.db.Where("process_id = ? AND step = ?", process.ID, process.CurrentStep).First(&currentStep).Error; err != nil {
		// 无步骤记录（旧数据兼容）：直接通过
		h.db.Model(&process).Updates(map[string]interface{}{
			"status":      "approved",
			"approved_at": &now,
		})
		h.db.Preload("Template").Preload("ApplicantUser").Preload("Steps.ApproverUser").First(&process, process.ID)
		c.JSON(http.StatusOK, model.Response{Code: 200, Message: "审批通过", Data: process})
		return
	}

	tx := h.db.Begin()

	// 更新当前步骤为通过
	tx.Model(&currentStep).Updates(map[string]interface{}{
		"status":      "approved",
		"approver":    approverID,
		"comment":     req.Comment,
		"approved_at": &now,
	})

	// 推进到下一步 或 标记全部通过
	if process.CurrentStep >= process.TotalSteps {
		tx.Model(&process).Updates(map[string]interface{}{
			"status":      "approved",
			"approved_at": &now,
		})
	} else {
		tx.Model(&process).Update("current_step", process.CurrentStep+1)
	}

	tx.Commit()

	h.db.Preload("Template").Preload("ApplicantUser").Preload("Steps.ApproverUser").First(&process, process.ID)

	c.JSON(http.StatusOK, model.Response{
		Code:    200,
		Message: "审批通过",
		Data:    process,
	})
}

// RejectProcess 审批拒绝 // Logan.Li
func (h *ApprovalHandler) RejectProcess(c *gin.Context) {
	id, _ := strconv.Atoi(c.Param("id"))

	var req model.ApproveRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, model.Response{Code: 400, Message: "请求参数错误"})
		return
	}

	userIDVal, _ := c.Get("userID")
	approverID := toUint(userIDVal)

	var process model.ApprovalProcess
	if err := h.db.First(&process, id).Error; err != nil {
		c.JSON(http.StatusNotFound, model.Response{Code: 404, Message: "流程不存在"})
		return
	}

	if process.Status != "pending" {
		c.JSON(http.StatusBadRequest, model.Response{Code: 400, Message: "该申请已处理"})
		return
	}

	now := time.Now()
	tx := h.db.Begin()

	// 更新当前步骤为拒绝
	tx.Model(&model.ApprovalStep{}).Where("process_id = ? AND step = ?", process.ID, process.CurrentStep).
		Updates(map[string]interface{}{
			"status":      "rejected",
			"approver":    approverID,
			"comment":     req.Comment,
			"approved_at": &now,
		})

	tx.Model(&process).Updates(map[string]interface{}{
		"status":        "rejected",
		"rejected_at":   &now,
		"reject_reason": req.Comment,
	})

	tx.Commit()

	h.db.Preload("Template").Preload("ApplicantUser").Preload("Steps.ApproverUser").First(&process, process.ID)

	c.JSON(http.StatusOK, model.Response{
		Code:    200,
		Message: "已拒绝",
		Data:    process,
	})
}