// Copyright 2016-2020, Pulumi Corporation.
//
// 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 codegen

import (
	"regexp"

	"github.com/pgavlin/goldmark/ast"

	"github.com/pulumi/pulumi/pkg/v2/codegen/schema"
	"github.com/pulumi/pulumi/sdk/v2/go/common/util/contract"
)

var (
	// IMPORTANT! The following regexp's contain named capturing groups.
	// It's the `?P<group_name>` where group_name can be any name.
	// When changing the group names, be sure to change the reference to
	// the corresponding group name below where they are used as well.

	// SurroundingTextRE is regexp to match the content between the {{% examples %}} short-code
	// including the short-codes themselves.
	SurroundingTextRE = regexp.MustCompile("({{% examples %}}(.|\n)*?{{% /examples %}})")
	// IndividualExampleRE is a regexp to match a single example section surrounded by the {{% example %}} short-code.
	IndividualExampleRE = regexp.MustCompile(
		"(?P<example_start>{{% example %}})(?P<example_content>(.|\n)*?)(?P<example_end>{{% /example %}})")
	// H3TitleRE is a regexp to match an h3 title tag.
	H3TitleRE = regexp.MustCompile("(### .*)")

	// The following regexp's match the code snippet blocks in a single example section.

	// TSCodeSnippetRE is a regexp to match a TypeScript code snippet.
	TSCodeSnippetRE = regexp.MustCompile("(```(typescript))((.|\n)*?)(```)")
	// GoCodeSnippetRE is a regexp to match a Go code snippet.
	GoCodeSnippetRE = regexp.MustCompile("(```(go))((.|\n)*?)(```)")
	// PythonCodeSnippetRE is a regexp to match a Python code snippet.
	PythonCodeSnippetRE = regexp.MustCompile("(```(python))((.|\n)*?)(```)")
	// CSharpCodeSnippetRE is a regexp to match a C# code snippet.
	CSharpCodeSnippetRE = regexp.MustCompile("(```(csharp))((.|\n)*?)(```)")
)

// DocLanguageHelper is an interface for extracting language-specific information from a Pulumi schema.
// See the implementation for this interface under each of the language code generators.
type DocLanguageHelper interface {
	GetPropertyName(p *schema.Property) (string, error)
	GetDocLinkForResourceType(pkg *schema.Package, moduleName, typeName string) string
	GetDocLinkForPulumiType(pkg *schema.Package, typeName string) string
	GetDocLinkForResourceInputOrOutputType(pkg *schema.Package, moduleName, typeName string, input bool) string
	GetDocLinkForFunctionInputOrOutputType(pkg *schema.Package, moduleName, typeName string, input bool) string
	GetDocLinkForBuiltInType(typeName string) string
	GetLanguageTypeString(pkg *schema.Package, moduleName string, t schema.Type, input, optional bool) string

	GetFunctionName(modName string, f *schema.Function) string
	// GetResourceFunctionResultName returns the name of the result type when a static resource function is used to lookup
	// an existing resource.
	GetResourceFunctionResultName(modName string, f *schema.Function) string
	// GetModuleDocLink returns the display name and the link for a module (including root modules) in a given package.
	GetModuleDocLink(pkg *schema.Package, modName string) (string, string)
}

// GetFirstMatchedGroupsFromRegex returns the groups for the first match of a regexp.
func GetFirstMatchedGroupsFromRegex(regex *regexp.Regexp, str string) map[string]string {
	groups := map[string]string{}

	// Get all matching groups.
	matches := regex.FindAllStringSubmatch(str, -1)
	if len(matches) == 0 {
		return groups
	}

	firstMatch := matches[0]
	// Get the named groups in our regex.
	groupNames := regex.SubexpNames()

	for i, value := range firstMatch {
		groups[groupNames[i]] = value
	}

	return groups
}

// GetAllMatchedGroupsFromRegex returns all matches and the respective groups for a regexp.
func GetAllMatchedGroupsFromRegex(regex *regexp.Regexp, str string) map[string][]string {
	// Get all matching groups.
	matches := regex.FindAllStringSubmatch(str, -1)
	// Get the named groups in our regex.
	groupNames := regex.SubexpNames()

	groups := map[string][]string{}
	for _, match := range matches {
		for j, value := range match {
			if existing, ok := groups[groupNames[j]]; ok {
				existing = append(existing, value)
				groups[groupNames[j]] = existing
				continue
			}
			groups[groupNames[j]] = []string{value}
		}
	}

	return groups
}

// ExtractExamplesSection returns the content available between the first {{% examples %}} shortcode.
// If no such section exists, the second return value will be false.
func ExtractExamplesSection(description string) (string, bool) {
	if description == "" {
		return "", false
	}

	source := []byte(description)
	parsed := schema.ParseDocs(source)

	var examples ast.Node
	err := ast.Walk(parsed, func(n ast.Node, enter bool) (ast.WalkStatus, error) {
		if shortcode, ok := n.(*schema.Shortcode); ok && string(shortcode.Name) == schema.ExamplesShortcode {
			examples = shortcode
			return ast.WalkStop, nil
		}
		return ast.WalkContinue, nil
	})
	contract.AssertNoError(err)

	if examples == nil || !examples.HasChildren() {
		return "", false
	}

	doc := ast.NewDocument()

	var c, next ast.Node
	for c = examples.FirstChild(); c != nil; c = next {
		next = c.NextSibling()
		doc.AppendChild(doc, c)
	}
	return schema.RenderDocsToString(source, doc), true
}

func stripNonRelevantExamples(source []byte, node ast.Node, lang string) {
	var c, next ast.Node
	for c = node.FirstChild(); c != nil; c = next {
		stripNonRelevantExamples(source, c, lang)

		next = c.NextSibling()
		switch c := c.(type) {
		case *ast.FencedCodeBlock:
			if string(c.Language(source)) != lang {
				node.RemoveChild(node, c)
			}
		case *schema.Shortcode:
			switch string(c.Name) {
			case schema.ExampleShortcode:
				hasCode := false
				for gc := c.FirstChild(); gc != nil; gc = gc.NextSibling() {
					if gc.Kind() == ast.KindFencedCodeBlock {
						hasCode = true
						break
					}
				}
				if hasCode {
					var grandchild, nextGrandchild ast.Node
					for grandchild = c.FirstChild(); grandchild != nil; grandchild = nextGrandchild {
						nextGrandchild = grandchild.NextSibling()
						node.InsertBefore(node, c, grandchild)
					}
				}
				node.RemoveChild(node, c)
			case schema.ExamplesShortcode:
				if first := c.FirstChild(); first != nil {
					first.SetBlankPreviousLines(c.HasBlankPreviousLines())
				}

				var grandchild, nextGrandchild ast.Node
				for grandchild = c.FirstChild(); grandchild != nil; grandchild = nextGrandchild {
					nextGrandchild = grandchild.NextSibling()
					node.InsertBefore(node, c, grandchild)
				}
				node.RemoveChild(node, c)
			}
		}
	}
}

// StripNonRelevantExamples strips the non-relevant language snippets from a resource's description.
func StripNonRelevantExamples(description string, lang string) string {
	if description == "" {
		return ""
	}

	source := []byte(description)
	parsed := schema.ParseDocs(source)
	stripNonRelevantExamples(source, parsed, lang)
	return schema.RenderDocsToString(source, parsed)
}