package database

import (
	"database/sql"
	"errors"
	"fmt"
	"strings"
	"time"

	log "maunium.net/go/maulogger/v2"

	"maunium.net/go/mautrix/id"
	"maunium.net/go/mautrix/util/dbutil"
)

type MessageQuery struct {
	db  *Database
	log log.Logger
}

const (
	messageSelect = "SELECT dcid, dc_attachment_id, dc_edit_index, dc_chan_id, dc_chan_receiver, dc_sender, timestamp, dc_thread_id, mxid FROM message"
)

func (mq *MessageQuery) New() *Message {
	return &Message{
		db:  mq.db,
		log: mq.log,
	}
}

func (mq *MessageQuery) scanAll(rows dbutil.Rows, err error) []*Message {
	if err != nil {
		mq.log.Warnfln("Failed to query many messages: %v", err)
		panic(err)
	} else if rows == nil {
		return nil
	}

	var messages []*Message
	for rows.Next() {
		messages = append(messages, mq.New().Scan(rows))
	}

	return messages
}

func (mq *MessageQuery) GetByDiscordID(key PortalKey, discordID string) []*Message {
	query := messageSelect + " WHERE dc_chan_id=$1 AND dc_chan_receiver=$2 AND dcid=$3 AND dc_edit_index=0 ORDER BY dc_attachment_id ASC"
	return mq.scanAll(mq.db.Query(query, key.ChannelID, key.Receiver, discordID))
}

func (mq *MessageQuery) GetFirstByDiscordID(key PortalKey, discordID string) *Message {
	query := messageSelect + " WHERE dc_chan_id=$1 AND dc_chan_receiver=$2 AND dcid=$3 AND dc_edit_index=0 ORDER BY dc_attachment_id ASC LIMIT 1"
	return mq.New().Scan(mq.db.QueryRow(query, key.ChannelID, key.Receiver, discordID))
}

func (mq *MessageQuery) GetLastByDiscordID(key PortalKey, discordID string) *Message {
	query := messageSelect + " WHERE dc_chan_id=$1 AND dc_chan_receiver=$2 AND dcid=$3 AND dc_edit_index=0 ORDER BY dc_attachment_id DESC LIMIT 1"
	return mq.New().Scan(mq.db.QueryRow(query, key.ChannelID, key.Receiver, discordID))
}

func (mq *MessageQuery) GetClosestBefore(key PortalKey, threadID string, ts time.Time) *Message {
	query := messageSelect + " WHERE dc_chan_id=$1 AND dc_chan_receiver=$2 AND dc_thread_id=$3 AND timestamp<=$4 ORDER BY timestamp DESC, dc_attachment_id DESC LIMIT 1"
	return mq.New().Scan(mq.db.QueryRow(query, key.ChannelID, key.Receiver, threadID, ts.UnixMilli()))
}

func (mq *MessageQuery) GetLastInThread(key PortalKey, threadID string) *Message {
	query := messageSelect + " WHERE dc_chan_id=$1 AND dc_chan_receiver=$2 AND dc_thread_id=$3 AND dc_edit_index=0 ORDER BY timestamp DESC, dc_attachment_id DESC LIMIT 1"
	return mq.New().Scan(mq.db.QueryRow(query, key.ChannelID, key.Receiver, threadID))
}

func (mq *MessageQuery) DeleteAll(key PortalKey) {
	query := "DELETE FROM message WHERE dc_chan_id=$1 AND dc_chan_receiver=$2"
	_, err := mq.db.Exec(query, key.ChannelID, key.Receiver)
	if err != nil {
		mq.log.Warnfln("Failed to delete messages of %s: %v", key, err)
		panic(err)
	}
}

func (mq *MessageQuery) GetByMXID(key PortalKey, mxid id.EventID) *Message {
	query := messageSelect + " WHERE dc_chan_id=$1 AND dc_chan_receiver=$2 AND mxid=$3"

	row := mq.db.QueryRow(query, key.ChannelID, key.Receiver, mxid)
	if row == nil {
		return nil
	}

	return mq.New().Scan(row)
}

type Message struct {
	db  *Database
	log log.Logger

	DiscordID    string
	AttachmentID string
	EditIndex    int
	Channel      PortalKey
	SenderID     string
	Timestamp    time.Time
	ThreadID     string

	MXID id.EventID
}

func (m *Message) DiscordProtoChannelID() string {
	if m.ThreadID != "" {
		return m.ThreadID
	} else {
		return m.Channel.ChannelID
	}
}

func (m *Message) Scan(row dbutil.Scannable) *Message {
	var ts int64

	err := row.Scan(&m.DiscordID, &m.AttachmentID, &m.EditIndex, &m.Channel.ChannelID, &m.Channel.Receiver, &m.SenderID, &ts, &m.ThreadID, &m.MXID)
	if err != nil {
		if !errors.Is(err, sql.ErrNoRows) {
			m.log.Errorln("Database scan failed:", err)
			panic(err)
		}

		return nil
	}

	if ts != 0 {
		m.Timestamp = time.UnixMilli(ts)
	}

	return m
}

const messageInsertQuery = `
	INSERT INTO message (
		dcid, dc_attachment_id, dc_edit_index, dc_chan_id, dc_chan_receiver, dc_sender, timestamp, dc_thread_id, mxid
	)
	VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
`

var messageMassInsertTemplate = strings.Replace(messageInsertQuery, "($1, $2, $3, $4, $5, $6, $7, $8, $9)", "%s", 1)

type MessagePart struct {
	AttachmentID string
	MXID         id.EventID
}

func (m *Message) MassInsert(msgs []MessagePart) {
	if len(msgs) == 0 {
		return
	}
	valueStringFormat := "($1, $%d, $2, $3, $4, $5, $6, $7, $%d)"
	if m.db.Dialect == dbutil.SQLite {
		valueStringFormat = strings.ReplaceAll(valueStringFormat, "$", "?")
	}
	params := make([]interface{}, 7+len(msgs)*2)
	placeholders := make([]string, len(msgs))
	params[0] = m.DiscordID
	params[1] = m.EditIndex
	params[2] = m.Channel.ChannelID
	params[3] = m.Channel.Receiver
	params[4] = m.SenderID
	params[5] = m.Timestamp.UnixMilli()
	params[6] = m.ThreadID
	for i, msg := range msgs {
		params[7+i*2] = msg.AttachmentID
		params[7+i*2+1] = msg.MXID
		placeholders[i] = fmt.Sprintf(valueStringFormat, 7+i*2+1, 7+i*2+2)
	}
	_, err := m.db.Exec(fmt.Sprintf(messageMassInsertTemplate, strings.Join(placeholders, ", ")), params...)
	if err != nil {
		m.log.Warnfln("Failed to insert %d parts of %s@%s: %v", len(msgs), m.DiscordID, m.Channel, err)
		panic(err)
	}
}

func (m *Message) Insert() {
	_, err := m.db.Exec(messageInsertQuery,
		m.DiscordID, m.AttachmentID, m.EditIndex, m.Channel.ChannelID, m.Channel.Receiver, m.SenderID,
		m.Timestamp.UnixMilli(), m.ThreadID, m.MXID)

	if err != nil {
		m.log.Warnfln("Failed to insert %s@%s: %v", m.DiscordID, m.Channel, err)
		panic(err)
	}
}

func (m *Message) Delete() {
	query := "DELETE FROM message WHERE dcid=$1 AND dc_chan_id=$2 AND dc_chan_receiver=$3 AND dc_attachment_id=$4"
	_, err := m.db.Exec(query, m.DiscordID, m.Channel.ChannelID, m.Channel.Receiver, m.AttachmentID)
	if err != nil {
		m.log.Warnfln("Failed to delete %q of %s@%s: %v", m.AttachmentID, m.DiscordID, m.Channel, err)
		panic(err)
	}
}