/*
MIT License

# Copyright (c) 2023 WittonBell

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
package main

import (
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/xuri/excelize/v2"
)

var taskIDField string
var taskTitleField string
var preTaskField string
var noCaseSensitive bool // 是否不區(qū)分大小寫
var fieldNameRow uint    // 字段名所在行號
var dataStartRow uint    // 數(shù)據(jù)開始行號

type node struct {
	taskID    string
	taskTitle string
}

type multiMap map[string][]*node

func (slf multiMap) Add(key string, nd *node) {
	if len(slf) == 0 {
		slf[key] = []*node{nd}
	} else {
		slf[key] = append(slf[key], nd)
	}
}

func (slf multiMap) Get(key string) []*node {
	if slf == nil {
		return nil
	}
	return slf[key]
}

func (slf multiMap) Del(key string) {
	delete(slf, key)
}

func searchKeyCol(rows *excelize.Rows) (TaskIDCol, PreTaskIDCol, TitleCol int) {
	row, err := rows.Columns()
	if err != nil {
		fmt.Println(err.Error())
	}

	for i, col := range row {
		name := col
		if noCaseSensitive {
			name = strings.ToLower(col)
		}
		if name == preTaskField {
			PreTaskIDCol = i + 1
		} else if name == taskIDField {
			TaskIDCol = i + 1
		} else if name == taskTitleField {
			TitleCol = i + 1
		}
	}
	return
}

func readExcel(filePath string) multiMap {
	fd, err := excelize.OpenFile(filePath)
	if err != nil {
		fmt.Printf("讀取文件`%s`失敗", filePath)
		return nil
	}
	defer func() {
		fd.Close()
	}()
	TaskIDCol, PreTaskIDCol, TitleCol := -1, -1, -1
	sheetName := fd.GetSheetName(0)
	rows, err := fd.Rows(sheetName)
	if err != nil {
		return nil
	}
	defer func() {
		rows.Close()
	}()

	m := multiMap{}
	for i := 1; rows.Next(); i++ {
		if i == int(fieldNameRow) {
			TaskIDCol, PreTaskIDCol, TitleCol = searchKeyCol(rows)
			isOk := true
			if TaskIDCol < 0 {
				isOk = false
				fmt.Printf("要求字段名：%s\n", taskIDField)
			}
			if PreTaskIDCol < 0 {
				isOk = false
				fmt.Printf("要求字段名：%s\n", preTaskField)
			}
			if TitleCol < 0 {
				isOk = false
				fmt.Printf("要求字段名：%s\n", taskTitleField)
			}
			if !isOk {
				return nil
			}
		}
		if i < int(dataStartRow) {
			continue
		}
		TaskIDCell, err := excelize.CoordinatesToCellName(TaskIDCol, i)
		if err != nil {
			continue
		}
		PreTaskIDCell, err := excelize.CoordinatesToCellName(PreTaskIDCol, i)
		if err != nil {
			continue
		}

		TitleColCell, err := excelize.CoordinatesToCellName(TitleCol, i)
		if err != nil {
			continue
		}

		TaskID, err := fd.GetCellValue(sheetName, TaskIDCell)
		if err != nil || TaskID == "" {
			continue
		}

		Title, err := fd.GetCellValue(sheetName, TitleColCell)
		if err != nil || Title == "" {
			continue
		}

		PreTaskID, err := fd.GetCellValue(sheetName, PreTaskIDCell)
		if err != nil {
			continue
		}

		if PreTaskID == "" {
			PreTaskID = "0"
		}

		m.Add(PreTaskID, &node{taskID: TaskID, taskTitle: Title})
	}

	return m
}

func usage() {
	w := flag.CommandLine.Output()
	fmt.Fprintf(w, "%s 應用程序是將Excel任務表中的關(guān)系轉(zhuǎn)換成Markdown的mermaid圖，方便使用Markdown工具直觀地查看任務依賴。", filepath.Base(os.Args[0]))
	fmt.Fprintln(w)
	fmt.Fprintf(w, "命令格式：%s -hr [字段所在行號] -dr [數(shù)據(jù)起始行號] [-nc] -id [任務ID字段名] -t [任務標題字段名] -pid [前置任務ID字段名] -o <輸出文件> <Excel文件路徑>", filepath.Base(os.Args[0]))
	fmt.Fprintln(w)
	flag.CommandLine.PrintDefaults()
	fmt.Fprintln(w, "  -h")
	fmt.Fprintln(w, "    \t顯示此幫助")
}

func main() {
	var outputFile string

	flag.CommandLine.Usage = usage
	flag.BoolVar(&noCaseSensitive, "nc", false, "字段名不區(qū)分大小寫")
	flag.UintVar(&fieldNameRow, "hr", 1, "字段所在行號")
	flag.UintVar(&dataStartRow, "dr", 2, "數(shù)據(jù)起始行號")
	flag.StringVar(&taskIDField, "id", "ID", "-id [任務ID字段名]")
	flag.StringVar(&taskTitleField, "t", "Title", "-t [任務標題字段名]")
	flag.StringVar(&preTaskField, "pid", "PreTask", "-pid [前置任務ID字段名]")
	flag.StringVar(&outputFile, "o", "任務圖.md", "-o <輸出文件>")

	flag.Parse()
	if flag.NArg() < 1 {
		usage()
		return
	}
	if noCaseSensitive {
		taskIDField = strings.ToLower(taskIDField)
		taskTitleField = strings.ToLower(taskTitleField)
		preTaskField = strings.ToLower(preTaskField)
	}
	mapTask := readExcel(flag.Arg(0))
	buildGraph(mapTask, outputFile)
}

func buildGraph(mapTask multiMap, outputFile string) {
	graph := "```mermaid\ngraph TB\n"
	graph += "subgraph  \n"
	root := mapTask.Get("0")
	for _, v := range root {
		graph += visit(rootNodeName, v, mapTask)
	}
	graph += "end\n"
	graph += "```"

	os.WriteFile(outputFile, []byte(graph), os.ModePerm)

	fmt.Println("完成")
}

func visit(parent string, nd *node, mapTask multiMap) string {
	slice := mapTask.Get(nd.taskID)
	graph := fmt.Sprintf("%s --> %s:%s\n", parent, nd.taskID, nd.taskTitle)
	if parent == rootNodeName {
		graph += "subgraph  \n"
	}
	for _, x := range slice {
		graph += visit(fmt.Sprintf("%s:%s", nd.taskID, nd.taskTitle), x, mapTask)
	}
	mapTask.Del(nd.taskID)
	if parent == rootNodeName {
		graph += "end\n"
	}
	return graph
}