// Copyright 2016 bee 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 main

import (
	"bytes"
	"go/ast"
	"os"
	"path"
	"strings"
	"text/template"
	"unicode"
)

type Policy struct {
	Method   string
	Path     string
	Policies []string
}

var (
	policyList     = make(map[string]map[string]*Policy) //controllername -> method -> policy
	policyPathList = make(map[string]map[string]*Policy) //path -> method -> policy
)

func controllerFindPolicies(comments *ast.CommentGroup, controllerName, pkgpath string) {
	if comments == nil || comments.List == nil {
		return
	}
	for _, c := range comments.List {
		t := strings.TrimSpace(strings.TrimLeft(c.Text, "//"))
		if strings.HasPrefix(t, "@policy") {
			policy := Policy{
				Method: "*",
			}
			policyFields := strings.FieldsFunc(t[len("@policy"):], func(c rune) bool { return !unicode.IsLetter(c) && !unicode.IsNumber(c) && c != '_' })
			for _, val := range policyFields {
				policy.Policies = append(policy.Policies, val)
			}
			policyMethods := policyList[pkgpath+controllerName]
			if policyMethods == nil {
				policyMethods = make(map[string]*Policy)
				policyList[pkgpath+controllerName] = policyMethods
			}
			if pm := policyMethods[policy.Method]; pm != nil {
				for _, curPolicy := range policy.Policies {
					pm.Policies = append(pm.Policies, curPolicy)
				}
			} else {
				policyMethods[policy.Method] = &policy
			}
		}
	}
}

func generatePolicies(curpath string) {
	fn := template.FuncMap{
		"join": strings.Join,
	}

	tmpl, err := template.New("policy template").Funcs(fn).Parse(policyTpl)
	if err != nil {
		panic("Can't parse policy template: " + err.Error())
	}
	var buf bytes.Buffer
	err = tmpl.Execute(&buf, policyPathList)
	if err != nil {
		panic("Can't execute policy template: " + err.Error())

	}
	policyFile, err := os.Create(path.Join(curpath, "policies", "policies_autogen.go"))
	if err != nil {
		panic(err)
	}
	defer policyFile.Close()

	_, err = policyFile.Write(buf.Bytes())
	if err != nil {
		panic(err)
	}
}

var policyTpl = `// This file was auto-generated by bee tools, do not change it!
package policies

import "github.com/astaxie/beego"

func init() {
{{ range $path, $policyList := . }}{{ range $, $policy := $policyList }}	beego.Policy("{{$path}}{{$policy.Path}}", "{{$policy.Method}}", {{ join $policy.Policies ", " }})
{{ end }}{{ end }}
}
`