// Copyright 2019 The Hugo 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 hooks

import (
	"io"

	"github.com/gohugoio/hugo/common/hugio"
	"github.com/gohugoio/hugo/common/text"
	"github.com/gohugoio/hugo/identity"
	"github.com/gohugoio/hugo/markup/internal/attributes"
)

var _ AttributesOptionsSliceProvider = (*attributes.AttributesHolder)(nil)

type AttributesProvider interface {
	Attributes() map[string]interface{}
}

type LinkContext interface {
	Page() interface{}
	Destination() string
	Title() string
	Text() string
	PlainText() string
}

type CodeblockContext interface {
	AttributesProvider
	text.Positioner
	Options() map[string]interface{}
	Lang() string
	Code() string
	Ordinal() int
	Page() interface{}
}

type AttributesOptionsSliceProvider interface {
	AttributesSlice() []attributes.Attribute
	OptionsSlice() []attributes.Attribute
}

type LinkRenderer interface {
	RenderLink(w io.Writer, ctx LinkContext) error
	identity.Provider
}

type CodeBlockRenderer interface {
	RenderCodeblock(w hugio.FlexiWriter, ctx CodeblockContext) error
	identity.Provider
}

type IsDefaultCodeBlockRendererProvider interface {
	IsDefaultCodeBlockRenderer() bool
}

// HeadingContext contains accessors to all attributes that a HeadingRenderer
// can use to render a heading.
type HeadingContext interface {
	// Page is the page containing the heading.
	Page() interface{}
	// Level is the level of the header (i.e. 1 for top-level, 2 for sub-level, etc.).
	Level() int
	// Anchor is the HTML id assigned to the heading.
	Anchor() string
	// Text is the rendered (HTML) heading text, excluding the heading marker.
	Text() string
	// PlainText is the unrendered version of Text.
	PlainText() string

	// Attributes (e.g. CSS classes)
	AttributesProvider
}

// HeadingRenderer describes a uniquely identifiable rendering hook.
type HeadingRenderer interface {
	// Render writes the rendered content to w using the data in w.
	RenderHeading(w io.Writer, ctx HeadingContext) error
	identity.Provider
}

// ElementPositionRevolver provides a way to resolve the start Position
// of a markdown element in the original source document.
// This may be both slow and aproximate, so should only be
// used for error logging.
type ElementPositionRevolver interface {
	ResolvePosition(ctx interface{}) text.Position
}

type RendererType int

const (
	LinkRendererType RendererType = iota + 1
	ImageRendererType
	HeadingRendererType
	CodeBlockRendererType
)

type GetRendererFunc func(t RendererType, id interface{}) interface{}