package common

import (
	"crypto/ecdsa"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"errors"
	"fmt"
	"strings"
	"unicode"
	"unicode/utf8"

	"github.com/golang/protobuf/proto"

	"github.com/status-im/markdown"
	"github.com/status-im/markdown/ast"

	"github.com/status-im/status-go/eth-node/crypto"
	"github.com/status-im/status-go/images"
	"github.com/status-im/status-go/protocol/protobuf"
)

// QuotedMessage contains the original text of the message replied to
type QuotedMessage struct {
	// From is a public key of the author of the message.
	From       string          `json:"from"`
	Text       string          `json:"text"`
	ParsedText json.RawMessage `json:"parsedText,omitempty"`
	// Base64Image is the converted base64 image
	Base64Image string `json:"image,omitempty"`
	// Base64Audio is the converted base64 audio
	Base64Audio string `json:"audio,omitempty"`
	// AudioDurationMs is the audio duration in milliseconds
	AudioDurationMs uint64 `json:"audioDurationMs,omitempty"`
	// CommunityID is the id of the community advertised
	CommunityID string `json:"communityId,omitempty"`
}

type CommandState int

const (
	CommandStateRequestAddressForTransaction CommandState = iota + 1
	CommandStateRequestAddressForTransactionDeclined
	CommandStateRequestAddressForTransactionAccepted
	CommandStateRequestTransaction
	CommandStateRequestTransactionDeclined
	CommandStateTransactionPending
	CommandStateTransactionSent
)

type CommandParameters struct {
	// ID is the ID of the initial message
	ID string `json:"id"`
	// From is the address we are sending the command from
	From string `json:"from"`
	// Address is the address sent with the command
	Address string `json:"address"`
	// Contract is the contract address for ERC20 tokens
	Contract string `json:"contract"`
	// Value is the value as a string sent
	Value string `json:"value"`
	// TransactionHash is the hash of the transaction
	TransactionHash string `json:"transactionHash"`
	// CommandState is the state of the command
	CommandState CommandState `json:"commandState"`
	// The Signature of the pk-bytes+transaction-hash from the wallet
	// address originating
	Signature []byte `json:"signature"`
}

func (c *CommandParameters) IsTokenTransfer() bool {
	return len(c.Contract) != 0
}

const (
	OutgoingStatusSending   = "sending"
	OutgoingStatusSent      = "sent"
	OutgoingStatusDelivered = "delivered"
)

// Message represents a message record in the database,
// more specifically in user_messages table.
type Message struct {
	protobuf.ChatMessage

	// ID calculated as keccak256(compressedAuthorPubKey, data) where data is unencrypted payload.
	ID string `json:"id"`
	// WhisperTimestamp is a timestamp of a Whisper envelope.
	WhisperTimestamp uint64 `json:"whisperTimestamp"`
	// From is a public key of the author of the message.
	From string `json:"from"`
	// Random 3 words name
	Alias string `json:"alias"`
	// Identicon of the author
	Identicon string `json:"identicon"`
	// The chat id to be stored locally
	LocalChatID string `json:"localChatId"`
	// Seen set to true when user have read this message already
	Seen           bool   `json:"seen"`
	OutgoingStatus string `json:"outgoingStatus,omitempty"`

	QuotedMessage *QuotedMessage `json:"quotedMessage"`

	// CommandParameters is the parameters sent with the message
	CommandParameters *CommandParameters `json:"commandParameters"`

	// Computed fields
	// RTL is whether this is a right-to-left message (arabic/hebrew script etc)
	RTL bool `json:"rtl"`
	// ParsedText is the parsed markdown for displaying
	ParsedText []byte `json:"parsedText,omitempty"`
	// ParsedTextAst is the ast of the parsed text
	ParsedTextAst *ast.Node `json:"-"`
	// LineCount is the count of newlines in the message
	LineCount int `json:"lineCount"`
	// Base64Image is the converted base64 image
	Base64Image string `json:"image,omitempty"`
	// ImagePath is the path of the image to be sent
	ImagePath string `json:"imagePath,omitempty"`
	// Base64Audio is the converted base64 audio
	Base64Audio string `json:"audio,omitempty"`
	// AudioPath is the path of the audio to be sent
	AudioPath string `json:"audioPath,omitempty"`

	// CommunityID is the id of the community to advertise
	CommunityID string `json:"communityId,omitempty"`

	// Replace indicates that this is a replacement of a message
	// that has been updated
	Replace string `json:"replace,omitempty"`
	New     bool   `json:"new,omitempty"`

	SigPubKey *ecdsa.PublicKey `json:"-"`

	// Mentions is an array of mentions for a given message
	Mentions []string

	// Links is an array of links within given message
	Links []string
}

func (m *Message) MarshalJSON() ([]byte, error) {
	type StickerAlias struct {
		Hash string `json:"hash"`
		Pack int32  `json:"pack"`
	}
	item := struct {
		ID                string                           `json:"id"`
		WhisperTimestamp  uint64                           `json:"whisperTimestamp"`
		From              string                           `json:"from"`
		Alias             string                           `json:"alias"`
		Identicon         string                           `json:"identicon"`
		Seen              bool                             `json:"seen"`
		OutgoingStatus    string                           `json:"outgoingStatus,omitempty"`
		QuotedMessage     *QuotedMessage                   `json:"quotedMessage"`
		RTL               bool                             `json:"rtl"`
		ParsedText        json.RawMessage                  `json:"parsedText,omitempty"`
		LineCount         int                              `json:"lineCount"`
		Text              string                           `json:"text"`
		ChatID            string                           `json:"chatId"`
		LocalChatID       string                           `json:"localChatId"`
		Clock             uint64                           `json:"clock"`
		Replace           string                           `json:"replace"`
		ResponseTo        string                           `json:"responseTo"`
		New               bool                             `json:"new,omitempty"`
		EnsName           string                           `json:"ensName"`
		Image             string                           `json:"image,omitempty"`
		Audio             string                           `json:"audio,omitempty"`
		AudioDurationMs   uint64                           `json:"audioDurationMs,omitempty"`
		CommunityID       string                           `json:"communityId,omitempty"`
		Sticker           *StickerAlias                    `json:"sticker"`
		CommandParameters *CommandParameters               `json:"commandParameters"`
		Timestamp         uint64                           `json:"timestamp"`
		ContentType       protobuf.ChatMessage_ContentType `json:"contentType"`
		MessageType       protobuf.MessageType             `json:"messageType"`
		Mentions          []string                         `json:"mentions,omitempty"`
		Links             []string                         `json:"links,omitempty"`
	}{
		ID:                m.ID,
		WhisperTimestamp:  m.WhisperTimestamp,
		From:              m.From,
		Alias:             m.Alias,
		Identicon:         m.Identicon,
		Seen:              m.Seen,
		OutgoingStatus:    m.OutgoingStatus,
		QuotedMessage:     m.QuotedMessage,
		RTL:               m.RTL,
		ParsedText:        m.ParsedText,
		LineCount:         m.LineCount,
		Text:              m.Text,
		Replace:           m.Replace,
		ChatID:            m.ChatId,
		LocalChatID:       m.LocalChatID,
		Clock:             m.Clock,
		ResponseTo:        m.ResponseTo,
		New:               m.New,
		EnsName:           m.EnsName,
		Image:             m.Base64Image,
		Audio:             m.Base64Audio,
		CommunityID:       m.CommunityID,
		Timestamp:         m.Timestamp,
		ContentType:       m.ContentType,
		Mentions:          m.Mentions,
		Links:             m.Links,
		MessageType:       m.MessageType,
		CommandParameters: m.CommandParameters,
	}
	if sticker := m.GetSticker(); sticker != nil {
		item.Sticker = &StickerAlias{
			Pack: sticker.Pack,
			Hash: sticker.Hash,
		}
	}

	if audio := m.GetAudio(); audio != nil {
		item.AudioDurationMs = audio.DurationMs
	}

	return json.Marshal(item)
}

func (m *Message) UnmarshalJSON(data []byte) error {
	type Alias Message
	aux := struct {
		*Alias
		ResponseTo      string                           `json:"responseTo"`
		EnsName         string                           `json:"ensName"`
		ChatID          string                           `json:"chatId"`
		Sticker         *protobuf.StickerMessage         `json:"sticker"`
		AudioDurationMs uint64                           `json:"audioDurationMs"`
		ParsedText      json.RawMessage                  `json:"parsedText"`
		ContentType     protobuf.ChatMessage_ContentType `json:"contentType"`
	}{
		Alias: (*Alias)(m),
	}
	if err := json.Unmarshal(data, &aux); err != nil {
		return err
	}
	if aux.ContentType == protobuf.ChatMessage_STICKER {
		m.Payload = &protobuf.ChatMessage_Sticker{Sticker: aux.Sticker}
	}
	if aux.ContentType == protobuf.ChatMessage_AUDIO {
		m.Payload = &protobuf.ChatMessage_Audio{
			Audio: &protobuf.AudioMessage{DurationMs: aux.AudioDurationMs},
		}
	}
	m.ResponseTo = aux.ResponseTo
	m.EnsName = aux.EnsName
	m.ChatId = aux.ChatID
	m.ContentType = aux.ContentType
	m.ParsedText = aux.ParsedText
	return nil
}

// Check if the first character is Hebrew or Arabic or the RTL character
func isRTL(s string) bool {
	first, _ := utf8.DecodeRuneInString(s)
	return unicode.Is(unicode.Hebrew, first) ||
		unicode.Is(unicode.Arabic, first) ||
		// RTL character
		first == '\u200f'
}

// parseImage check the message contains an image, and if so
// it creates the a base64 encoded version of it.
func (m *Message) parseImage() error {
	if m.ContentType != protobuf.ChatMessage_IMAGE {
		return nil
	}
	image := m.GetImage()
	if image == nil {
		return errors.New("image empty")
	}

	payload := image.Payload

	e64 := base64.StdEncoding

	maxEncLen := e64.EncodedLen(len(payload))
	encBuf := make([]byte, maxEncLen)

	e64.Encode(encBuf, payload)

	mime, err := images.GetMimeType(image.Payload)

	if err != nil {
		return err
	}

	m.Base64Image = fmt.Sprintf("data:image/%s;base64,%s", mime, encBuf)

	return nil
}

// parseAudio check the message contains an audio, and if so
// it creates a base64 encoded version of it.
func (m *Message) parseAudio() error {
	if m.ContentType != protobuf.ChatMessage_AUDIO {
		return nil
	}
	audio := m.GetAudio()
	if audio == nil {
		return errors.New("audio empty")
	}

	payload := audio.Payload

	e64 := base64.StdEncoding

	maxEncLen := e64.EncodedLen(len(payload))
	encBuf := make([]byte, maxEncLen)

	e64.Encode(encBuf, payload)

	mime, err := getAudioMessageMIME(audio)

	if err != nil {
		return err
	}

	m.Base64Audio = fmt.Sprintf("data:audio/%s;base64,%s", mime, encBuf)

	return nil
}

// implement interface of https://github.com/status-im/markdown/blob/b9fe921681227b1dace4b56364e15edb3b698308/ast/node.go#L701
type SimplifiedTextVisitor struct {
	text           string
	canonicalNames map[string]string
}

func (v *SimplifiedTextVisitor) Visit(node ast.Node, entering bool) ast.WalkStatus {
	// only on entering we fetch, otherwise we go on
	if !entering {
		return ast.GoToNext
	}

	switch n := node.(type) {
	case *ast.Mention:
		literal := string(n.Literal)
		canonicalName, ok := v.canonicalNames[literal]
		if ok {
			v.text += canonicalName
		} else {
			v.text += literal
		}
	case *ast.Link:
		destination := string(n.Destination)
		v.text += destination
	default:
		var literal string

		leaf := node.AsLeaf()
		container := node.AsContainer()
		if leaf != nil {
			literal = string(leaf.Literal)
		} else if container != nil {
			literal = string(container.Literal)
		}
		v.text += literal
	}

	return ast.GoToNext
}

// implement interface of https://github.com/status-im/markdown/blob/b9fe921681227b1dace4b56364e15edb3b698308/ast/node.go#L701
type MentionsAndLinksVisitor struct {
	mentions []string
	links    []string
}

func (v *MentionsAndLinksVisitor) Visit(node ast.Node, entering bool) ast.WalkStatus {
	// only on entering we fetch, otherwise we go on
	if !entering {
		return ast.GoToNext
	}
	switch n := node.(type) {
	case *ast.Mention:
		v.mentions = append(v.mentions, string(n.Literal))
	case *ast.Link:
		v.links = append(v.links, string(n.Destination))
	}

	return ast.GoToNext
}

func extractMentionsAndLinks(parsedText ast.Node) ([]string, []string) {
	visitor := &MentionsAndLinksVisitor{}
	ast.Walk(parsedText, visitor)
	return visitor.mentions, visitor.links
}

// PrepareContent return the parsed content of the message, the line-count and whether
// is a right-to-left message
func (m *Message) PrepareContent() error {
	parsedText := markdown.Parse([]byte(m.Text), nil)
	m.Mentions, m.Links = extractMentionsAndLinks(parsedText)
	jsonParsedText, err := json.Marshal(parsedText)
	if err != nil {
		return err
	}
	m.ParsedTextAst = &parsedText
	m.ParsedText = jsonParsedText
	m.LineCount = strings.Count(m.Text, "\n")
	m.RTL = isRTL(m.Text)
	if err := m.parseImage(); err != nil {
		return err
	}
	return m.parseAudio()
}

// GetSimplifiedText returns a the text stripped of all the markdown and with mentions
// replaced by canonical names
func (m *Message) GetSimplifiedText(canonicalNames map[string]string) (string, error) {

	if m.ContentType == protobuf.ChatMessage_AUDIO {
		return "Audio", nil
	}
	if m.ContentType == protobuf.ChatMessage_STICKER {
		return "Sticker", nil
	}
	if m.ContentType == protobuf.ChatMessage_IMAGE {
		return "Image", nil
	}
	if m.ContentType == protobuf.ChatMessage_COMMUNITY {
		return "Community", nil
	}

	if m.ParsedTextAst == nil {
		err := m.PrepareContent()
		if err != nil {
			return "", err
		}
	}
	visitor := &SimplifiedTextVisitor{canonicalNames: canonicalNames}
	ast.Walk(*m.ParsedTextAst, visitor)
	return visitor.text, nil
}

func getAudioMessageMIME(i *protobuf.AudioMessage) (string, error) {
	switch i.Type {
	case protobuf.AudioMessage_AAC:
		return "aac", nil
	case protobuf.AudioMessage_AMR:
		return "amr", nil
	}

	return "", errors.New("audio format not supported")
}

// GetSigPubKey returns an ecdsa encoded public key
// this function is required to implement the ChatEntity interface
func (m Message) GetSigPubKey() *ecdsa.PublicKey {
	return m.SigPubKey
}

// GetProtoBuf returns the struct's embedded protobuf struct
// this function is required to implement the ChatEntity interface
func (m *Message) GetProtobuf() proto.Message {
	return &m.ChatMessage
}

// SetMessageType a setter for the MessageType field
// this function is required to implement the ChatEntity interface
func (m *Message) SetMessageType(messageType protobuf.MessageType) {
	m.MessageType = messageType
}

// WrapGroupMessage indicates whether we should wrap this in membership information
func (m *Message) WrapGroupMessage() bool {
	return true
}

// GetPublicKey attempts to return or recreate the *ecdsa.PublicKey of the Message sender.
// If the m.SigPubKey is set this will be returned
// If the m.From is present the string is decoded and unmarshalled into a *ecdsa.PublicKey, the m.SigPubKey is set and returned
// Else an error is thrown
// This function differs from GetSigPubKey() as this function may return an error
func (m *Message) GetSenderPubKey() (*ecdsa.PublicKey, error) {
	// TODO requires tests

	if m.SigPubKey != nil {
		return m.SigPubKey, nil
	}

	if len(m.From) > 0 {
		fromB, err := hex.DecodeString(m.From[2:])
		if err != nil {
			return nil, err
		}

		senderPubKey, err := crypto.UnmarshalPubkey(fromB)
		if err != nil {
			return nil, err
		}

		m.SigPubKey = senderPubKey
		return senderPubKey, nil
	}

	return nil, errors.New("no Message.SigPubKey or Message.From set unable to get public key")
}