const attachmentTypes = Object.freeze({
  image: ["image/png", "image/jpeg", "image/gif"]
})

module.exports.attachmentTypes = attachmentTypes

// Returns the first attachment from a message (if it exists)
function getMessageAttachment(message) {
  if (message.attachments.first()) {
    return message.attachments.first()
  } else if (message.embeds.length > 0 && message.embeds.toArray()[0].image) {
    return message.embeds.toArray()[0].image
  } else if (message.embeds.length > 0 && message.embeds.toArray()[0].thumbnail) {
    return message.embeds.toArray()[0].thumbnail
  }
  return;
}

module.exports.getMessageAttachment = getMessageAttachment

async function getRecentMedia(context, limit) {
  if (!context.message.channel) {
    return undefined;
  } else if (context.message.attachments.length > 0) {
    return [context.message.attachments.first()]
  }

  let messages = [];

  // Handle Replies
  if (context.message.messageReference) {
    messages = [[context.message.messageReference.messageId, await context.message.channel.fetchMessage(context.message.messageReference.messageId)]] // somewhat hacky but it works lol
  } else {
    messages = await context.message.channel.fetchMessages({
      limit: limit,
      before: context.message.id
    })
  }

  if (!messages) {
    return undefined;
  }

  let attachments = [];
  for (const m of messages) {
    let a = getMessageAttachment(m[1])
    if(a) attachments.push(a)
  }
  return attachments;
}


module.exports.getRecentVideo = async function(context, limit) {
  if (!context.message.channel) {
    return undefined;
  }

  // Handle Replies
  if (context.message.messageReference) {
    messages = [[context.message.messageReference.messageId, await context.message.channel.fetchMessage(context.message.messageReference.messageId)]] // somewhat hacky but it works lol
  } else {
    messages = await context.message.channel.fetchMessages({
      limit: limit,
      before: context.message.id
    })
  }

  if (!messages) {
    return undefined;
  }

  let attachments = [];
  for (const m of messages) {
    let message = m[1]
    if ( // Then the embed image
      message.embeds.length > 0 &&
      message.embeds.toArray()[0].video
    ) {
      attachments.push(message.embeds.toArray()[0].video)
    } else if (message.attachments.first() &&
    message.attachments.first().contentType?.includes("video")){
      attachments.push(message.attachments.first())
    }
  }
  return attachments;
}

function validateAttachment(attachment, type){
  let allowedTypes = attachmentTypes[type]
  if (attachment.contentType && allowedTypes.includes(attachment.contentType)) { // discord attachment
    return true
  } else if (!attachment.contentType) { // other form of media
    return true
  } else {
    return false
  }
}

module.exports.validateAttachment = validateAttachment

module.exports.getRecentImage = async function(context, limit){
  let attachments = await getRecentMedia(context, limit)

  let at;
  for (const a of attachments) {
    if(validateAttachment(a, "image") && at === undefined) at = a.url
  }
  return at;
}