package template

import (
	"errors"
	"gitee.com/lllgo/gopkg/files"
	"gitee.com/lllgo/gopkg/utils"
	"github.com/valyala/bytebufferpool"
	"io/ioutil"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"text/template"
)

type MetaKey interface{}

type FuncMap template.FuncMap

var (
	metaData         = map[MetaKey]interface{}{}
	templateFilePath string
)

type Config struct {
	//渲染模板资源根路径 配置的其它文件都相对该路径
	BasePath string
	//模板来源
	TplFile, TplDir, TplText string
	//渲染模板输出 如果都没配置就输出到控制台
	DestDir, DestFile string
	DestStdout        bool
	//变量开始和结束标志
	LeftDelim, RightDelim string
	//自定义函数
	Funcs FuncMap
	//渲染模板的数据
	Data interface{}
}

func AddMetaData(key MetaKey, val interface{}) error {
	metaData[key] = val
	return nil
}

func GetMetaData(key MetaKey) interface{} {
	return metaData[key]
}

func (c *Config) getData(data []interface{}) interface{} {
	if len(data) > 0 {
		return data[0]
	}
	return c.Data
}

func (c *Config) Render(data ...interface{}) ([]byte, error) {
	if c.TplFile == "" && c.TplText == "" {
		return nil, errors.New("请指定模板源")
	}

	t := c.getOriginalTemplate()

	//模板字符串优先级比文件高
	tempText := c.TplText
	if tempText == "" && c.TplFile != "" {
		tempText = getTmplByFile(c.TplFile)
	}

	return render(t, tempText, c.getData(data))
}

// 读取文件内容为字符串
func getTmplByFile(tmplFile string) string {
	bytes, err := ioutil.ReadFile(tmplFile)
	if err != nil {
		panic("读取模板文件失败" + err.Error())
	}
	return string(bytes)
}

// 封装渲染模板方式
func render(t *template.Template, tmplText string, data interface{}) ([]byte, error) {

	if tmplText == "" {
		return nil, errors.New("模板内容为空")
	}

	buf := bytebufferpool.Get()
	defer bytebufferpool.Put(buf)

	parse, err := t.Parse(tmplText)
	if err != nil {
		return nil, err
	}

	if err = parse.Execute(buf, data); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

// 封装写入到文件方法
func writeFile(content []byte, destFile string) error {

	dest := os.Stdout

	if destFile != "" {
		var err error
		dest, err = os.Create(destFile)
		if err != nil {
			return err
		}
		defer dest.Close()
	}

	_, err := dest.Write(content)
	return err
}

// 支持渲染结果输出到控制台、文件、文件目录(只有模板文件为目录时有效)
func (c *Config) Write(data ...interface{}) error {
	if c.TplDir == "" && c.TplFile == "" && c.TplText == "" {
		return errors.New("请指定模板源")
	}

	if c.TplFile != "" || c.TplText != "" {
		render, err := c.Render(data...)
		if err != nil {
			return err
		}
		return writeFile(render, c.DestFile)
	} else if c.TplDir != "" {

		t := c.getOriginalTemplate()

		allFile := files.GetAllFile(c.TplDir, "")

		for _, f := range allFile {
			tmplText := getTmplByFile(filepath.Join(c.TplDir, f))
			bytes, err := render(t, tmplText, c.getData(data))
			if err != nil {
				return err
			}

			destFile := ""
			if c.DestDir != "" {
				destFile = filepath.Join(c.DestDir, f)
			}

			err = writeFile(bytes, destFile)
			if err != nil {
				return err
			}
		}

	} else {
		return errors.New("不支持的配置")
	}

	return nil

}

func (c *Config) getOriginalTemplate() *template.Template {
	funcs := template.FuncMap{
		"contains":  contains,
		"exists":    exists,
		"split":     strings.Split,
		"replace":   strings.Replace,
		"default":   defaultValue,
		"parseUrl":  parseUrl,
		"atoi":      strconv.Atoi,
		"add":       add,
		"isTrue":    isTrue,
		"lower":     strings.ToLower,
		"upper":     strings.ToUpper,
		"jsonQuery": jsonQuery,
		"loop":      loop,
		"abs":       abs,
		"type":      getType,
	}

	for k, v := range c.Funcs {
		funcs[k] = v
	}

	if c.LeftDelim == "" {
		c.LeftDelim = "{{"
	}

	if c.RightDelim == "" {
		c.RightDelim = "}}"
	}

	c.TplDir = utils.GetDefStringWithBool(c.TplDir != "", files.Abs(c.BasePath, c.TplDir), c.TplDir)
	c.TplFile = utils.GetDefStringWithBool(c.TplFile != "", files.Abs(c.BasePath, c.TplFile), c.TplFile)
	c.DestFile = utils.GetDefStringWithBool(c.DestFile != "", files.Abs(c.BasePath, c.DestFile), c.DestFile)
	c.DestDir = utils.GetDefStringWithBool(c.DestDir != "", files.Abs(c.BasePath, c.DestDir), c.DestDir)

	if c.TplFile != "" {
		templateFilePath = c.TplFile
	}
	if c.TplDir != "" {
		templateFilePath = c.TplDir
	}

	t := template.New("").Funcs(funcs).Delims(c.LeftDelim, c.RightDelim)

	return t
}

func RenderText2File(tmplText, destFile string, data interface{}) error {
	t := Config{TplText: tmplText, DestFile: destFile}
	return t.Write(data)
}

func RenderText(tmplText string, data interface{}) ([]byte, error) {
	t := Config{TplText: tmplText}
	return t.Render(data)
}