1 files changed, 480 insertions, 0 deletions
diff --git a/modules/issue/template/template.go b/modules/issue/template/template.go
new file mode 100644
index 00000000..cf5fcf28
--- /dev/null
+++ b/modules/issue/template/template.go
@@ -0,0 +1,480 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package template
+
+import (
+	"fmt"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"code.gitea.io/gitea/modules/container"
+	api "code.gitea.io/gitea/modules/structs"
+
+	"gitea.com/go-chi/binding"
+)
+
+// Validate checks whether an IssueTemplate is considered valid, and returns the first error
+func Validate(template *api.IssueTemplate) error {
+	if err := validateMetadata(template); err != nil {
+		return err
+	}
+	if template.Type() == api.IssueTemplateTypeYaml {
+		if err := validateYaml(template); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func validateMetadata(template *api.IssueTemplate) error {
+	if strings.TrimSpace(template.Name) == "" {
+		return fmt.Errorf("'name' is required")
+	}
+	if strings.TrimSpace(template.About) == "" {
+		return fmt.Errorf("'about' is required")
+	}
+	return nil
+}
+
+func validateYaml(template *api.IssueTemplate) error {
+	if len(template.Fields) == 0 {
+		return fmt.Errorf("'body' is required")
+	}
+	ids := make(container.Set[string])
+	for idx, field := range template.Fields {
+		if err := validateID(field, idx, ids); err != nil {
+			return err
+		}
+		if err := validateLabel(field, idx); err != nil {
+			return err
+		}
+
+		position := newErrorPosition(idx, field.Type)
+		switch field.Type {
+		case api.IssueFormFieldTypeMarkdown:
+			if err := validateStringItem(position, field.Attributes, true, "value"); err != nil {
+				return err
+			}
+		case api.IssueFormFieldTypeTextarea:
+			if err := validateStringItem(position, field.Attributes, false,
+				"description",
+				"placeholder",
+				"value",
+				"render",
+			); err != nil {
+				return err
+			}
+		case api.IssueFormFieldTypeInput:
+			if err := validateStringItem(position, field.Attributes, false,
+				"description",
+				"placeholder",
+				"value",
+			); err != nil {
+				return err
+			}
+			if err := validateBoolItem(position, field.Validations, "is_number"); err != nil {
+				return err
+			}
+			if err := validateStringItem(position, field.Validations, false, "regex"); err != nil {
+				return err
+			}
+		case api.IssueFormFieldTypeDropdown:
+			if err := validateStringItem(position, field.Attributes, false, "description"); err != nil {
+				return err
+			}
+			if err := validateBoolItem(position, field.Attributes, "multiple"); err != nil {
+				return err
+			}
+			if err := validateOptions(field, idx); err != nil {
+				return err
+			}
+			if err := validateDropdownDefault(position, field.Attributes); err != nil {
+				return err
+			}
+		case api.IssueFormFieldTypeCheckboxes:
+			if err := validateStringItem(position, field.Attributes, false, "description"); err != nil {
+				return err
+			}
+			if err := validateOptions(field, idx); err != nil {
+				return err
+			}
+		default:
+			return position.Errorf("unknown type")
+		}
+
+		if err := validateRequired(field, idx); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func validateLabel(field *api.IssueFormField, idx int) error {
+	if field.Type == api.IssueFormFieldTypeMarkdown {
+		// The label is not required for a markdown field
+		return nil
+	}
+	return validateStringItem(newErrorPosition(idx, field.Type), field.Attributes, true, "label")
+}
+
+func validateRequired(field *api.IssueFormField, idx int) error {
+	if field.Type == api.IssueFormFieldTypeMarkdown || field.Type == api.IssueFormFieldTypeCheckboxes {
+		// The label is not required for a markdown or checkboxes field
+		return nil
+	}
+	if err := validateBoolItem(newErrorPosition(idx, field.Type), field.Validations, "required"); err != nil {
+		return err
+	}
+	if required, _ := field.Validations["required"].(bool); required && !field.VisibleOnForm() {
+		return newErrorPosition(idx, field.Type).Errorf("can not require a hidden field")
+	}
+	return nil
+}
+
+func validateID(field *api.IssueFormField, idx int, ids container.Set[string]) error {
+	if field.Type == api.IssueFormFieldTypeMarkdown {
+		// The ID is not required for a markdown field
+		return nil
+	}
+
+	position := newErrorPosition(idx, field.Type)
+	if field.ID == "" {
+		// If the ID is empty in yaml, template.Unmarshal will auto autofill it, so it cannot be empty
+		return position.Errorf("'id' is required")
+	}
+	if binding.AlphaDashPattern.MatchString(field.ID) {
+		return position.Errorf("'id' should contain only alphanumeric, '-' and '_'")
+	}
+	if !ids.Add(field.ID) {
+		return position.Errorf("'id' should be unique")
+	}
+	return nil
+}
+
+func validateOptions(field *api.IssueFormField, idx int) error {
+	if field.Type != api.IssueFormFieldTypeDropdown && field.Type != api.IssueFormFieldTypeCheckboxes {
+		return nil
+	}
+	position := newErrorPosition(idx, field.Type)
+
+	options, ok := field.Attributes["options"].([]any)
+	if !ok || len(options) == 0 {
+		return position.Errorf("'options' is required and should be a array")
+	}
+
+	for optIdx, option := range options {
+		position := newErrorPosition(idx, field.Type, optIdx)
+		switch field.Type {
+		case api.IssueFormFieldTypeDropdown:
+			if _, ok := option.(string); !ok {
+				return position.Errorf("should be a string")
+			}
+		case api.IssueFormFieldTypeCheckboxes:
+			opt, ok := option.(map[string]any)
+			if !ok {
+				return position.Errorf("should be a dictionary")
+			}
+			if label, ok := opt["label"].(string); !ok || label == "" {
+				return position.Errorf("'label' is required and should be a string")
+			}
+
+			if visibility, ok := opt["visible"]; ok {
+				visibilityList, ok := visibility.([]any)
+				if !ok {
+					return position.Errorf("'visible' should be list")
+				}
+				for _, visibleType := range visibilityList {
+					visibleType, ok := visibleType.(string)
+					if !ok || !(visibleType == "form" || visibleType == "content") {
+						return position.Errorf("'visible' list can only contain strings of 'form' and 'content'")
+					}
+				}
+			}
+
+			if required, ok := opt["required"]; ok {
+				if _, ok := required.(bool); !ok {
+					return position.Errorf("'required' should be a bool")
+				}
+
+				// validate if hidden field is required
+				if visibility, ok := opt["visible"]; ok {
+					visibilityList, _ := visibility.([]any)
+					isVisible := false
+					for _, v := range visibilityList {
+						if vv, _ := v.(string); vv == "form" {
+							isVisible = true
+							break
+						}
+					}
+					if !isVisible {
+						return position.Errorf("can not require a hidden checkbox")
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func validateStringItem(position errorPosition, m map[string]any, required bool, names ...string) error {
+	for _, name := range names {
+		v, ok := m[name]
+		if !ok {
+			if required {
+				return position.Errorf("'%s' is required", name)
+			}
+			return nil
+		}
+		attr, ok := v.(string)
+		if !ok {
+			return position.Errorf("'%s' should be a string", name)
+		}
+		if strings.TrimSpace(attr) == "" && required {
+			return position.Errorf("'%s' is required", name)
+		}
+	}
+	return nil
+}
+
+func validateBoolItem(position errorPosition, m map[string]any, names ...string) error {
+	for _, name := range names {
+		v, ok := m[name]
+		if !ok {
+			return nil
+		}
+		if _, ok := v.(bool); !ok {
+			return position.Errorf("'%s' should be a bool", name)
+		}
+	}
+	return nil
+}
+
+func validateDropdownDefault(position errorPosition, attributes map[string]any) error {
+	v, ok := attributes["default"]
+	if !ok {
+		return nil
+	}
+	defaultValue, ok := v.(int)
+	if !ok {
+		return position.Errorf("'default' should be an int")
+	}
+
+	options, ok := attributes["options"].([]any)
+	if !ok {
+		// should not happen
+		return position.Errorf("'options' is required and should be a array")
+	}
+	if defaultValue < 0 || defaultValue >= len(options) {
+		return position.Errorf("the value of 'default' is out of range")
+	}
+
+	return nil
+}
+
+type errorPosition string
+
+func (p errorPosition) Errorf(format string, a ...any) error {
+	return fmt.Errorf(string(p)+": "+format, a...)
+}
+
+func newErrorPosition(fieldIdx int, fieldType api.IssueFormFieldType, optionIndex ...int) errorPosition {
+	ret := fmt.Sprintf("body[%d](%s)", fieldIdx, fieldType)
+	if len(optionIndex) > 0 {
+		ret += fmt.Sprintf(", option[%d]", optionIndex[0])
+	}
+	return errorPosition(ret)
+}
+
+// RenderToMarkdown renders template to markdown with specified values
+func RenderToMarkdown(template *api.IssueTemplate, values url.Values) string {
+	builder := &strings.Builder{}
+
+	for _, field := range template.Fields {
+		f := &valuedField{
+			IssueFormField: field,
+			Values:         values,
+		}
+		if f.ID == "" || !f.VisibleInContent() {
+			continue
+		}
+		f.WriteTo(builder)
+	}
+
+	return builder.String()
+}
+
+type valuedField struct {
+	*api.IssueFormField
+	url.Values
+}
+
+func (f *valuedField) WriteTo(builder *strings.Builder) {
+	// write label
+	if !f.HideLabel() {
+		_, _ = fmt.Fprintf(builder, "### %s\n\n", f.Label())
+	}
+
+	blankPlaceholder := "_No response_\n"
+
+	// write body
+	switch f.Type {
+	case api.IssueFormFieldTypeCheckboxes:
+		for _, option := range f.Options() {
+			if !option.VisibleInContent() {
+				continue
+			}
+			checked := " "
+			if option.IsChecked() {
+				checked = "x"
+			}
+			_, _ = fmt.Fprintf(builder, "- [%s] %s\n", checked, option.Label())
+		}
+	case api.IssueFormFieldTypeDropdown:
+		var checkeds []string
+		for _, option := range f.Options() {
+			if option.IsChecked() {
+				checkeds = append(checkeds, option.Label())
+			}
+		}
+		if len(checkeds) > 0 {
+			_, _ = fmt.Fprintf(builder, "%s\n", strings.Join(checkeds, ", "))
+		} else {
+			_, _ = fmt.Fprint(builder, blankPlaceholder)
+		}
+	case api.IssueFormFieldTypeInput:
+		if value := f.Value(); value == "" {
+			_, _ = fmt.Fprint(builder, blankPlaceholder)
+		} else {
+			_, _ = fmt.Fprintf(builder, "%s\n", value)
+		}
+	case api.IssueFormFieldTypeTextarea:
+		if value := f.Value(); value == "" {
+			_, _ = fmt.Fprint(builder, blankPlaceholder)
+		} else if render := f.Render(); render != "" {
+			quotes := minQuotes(value)
+			_, _ = fmt.Fprintf(builder, "%s%s\n%s\n%s\n", quotes, f.Render(), value, quotes)
+		} else {
+			_, _ = fmt.Fprintf(builder, "%s\n", value)
+		}
+	case api.IssueFormFieldTypeMarkdown:
+		if value, ok := f.Attributes["value"].(string); ok {
+			_, _ = fmt.Fprintf(builder, "%s\n", value)
+		}
+	}
+	_, _ = fmt.Fprintln(builder)
+}
+
+func (f *valuedField) Label() string {
+	if label, ok := f.Attributes["label"].(string); ok {
+		return label
+	}
+	return ""
+}
+
+func (f *valuedField) HideLabel() bool {
+	if f.Type == api.IssueFormFieldTypeMarkdown {
+		return true
+	}
+	if label, ok := f.Attributes["hide_label"].(bool); ok {
+		return label
+	}
+	return false
+}
+
+func (f *valuedField) Render() string {
+	if render, ok := f.Attributes["render"].(string); ok {
+		return render
+	}
+	return ""
+}
+
+func (f *valuedField) Value() string {
+	return strings.TrimSpace(f.Get(fmt.Sprintf("form-field-" + f.ID)))
+}
+
+func (f *valuedField) Options() []*valuedOption {
+	if options, ok := f.Attributes["options"].([]any); ok {
+		ret := make([]*valuedOption, 0, len(options))
+		for i, option := range options {
+			ret = append(ret, &valuedOption{
+				index: i,
+				data:  option,
+				field: f,
+			})
+		}
+		return ret
+	}
+	return nil
+}
+
+type valuedOption struct {
+	index int
+	data  any
+	field *valuedField
+}
+
+func (o *valuedOption) Label() string {
+	switch o.field.Type {
+	case api.IssueFormFieldTypeDropdown:
+		if label, ok := o.data.(string); ok {
+			return label
+		}
+	case api.IssueFormFieldTypeCheckboxes:
+		if vs, ok := o.data.(map[string]any); ok {
+			if v, ok := vs["label"].(string); ok {
+				return v
+			}
+		}
+	}
+	return ""
+}
+
+func (o *valuedOption) IsChecked() bool {
+	switch o.field.Type {
+	case api.IssueFormFieldTypeDropdown:
+		checks := strings.Split(o.field.Get(fmt.Sprintf("form-field-%s", o.field.ID)), ",")
+		idx := strconv.Itoa(o.index)
+		for _, v := range checks {
+			if v == idx {
+				return true
+			}
+		}
+		return false
+	case api.IssueFormFieldTypeCheckboxes:
+		return o.field.Get(fmt.Sprintf("form-field-%s-%d", o.field.ID, o.index)) == "on"
+	}
+	return false
+}
+
+func (o *valuedOption) VisibleInContent() bool {
+	if o.field.Type == api.IssueFormFieldTypeCheckboxes {
+		if vs, ok := o.data.(map[string]any); ok {
+			if vl, ok := vs["visible"].([]any); ok {
+				for _, v := range vl {
+					if vv, _ := v.(string); vv == "content" {
+						return true
+					}
+				}
+				return false
+			}
+		}
+	}
+	return true
+}
+
+var minQuotesRegex = regexp.MustCompilePOSIX("^`{3,}")
+
+// minQuotes return 3 or more back-quotes.
+// If n back-quotes exists, use n+1 back-quotes to quote.
+func minQuotes(value string) string {
+	ret := "```"
+	for _, v := range minQuotesRegex.FindAllString(value, -1) {
+		if len(v) >= len(ret) {
+			ret = v + "`"
+		}
+	}
+	return ret
+}