/*
 * This file is part of the storage node for the Joystream project.
 * Copyright (C) 2019 Joystream Contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

'use strict'

const path = require('path')

const debug = require('debug')('joystream:colossus:api:asset')

const util_ranges = require('@joystream/storage-utils/ranges')
const filter = require('@joystream/storage-node-backend/filter')

function error_handler(response, err, code) {
	debug(err)
	response.status(err.code || code || 500).send({ message: err.toString() })
}

module.exports = function (storage, runtime) {
	const doc = {
		// parameters for all operations in this path
		parameters: [
			{
				name: 'id',
				in: 'path',
				required: true,
				description: 'Joystream Content ID',
				schema: {
					type: 'string',
				},
			},
		],

		// Head: report that ranges are OK
		async head(req, res, _next) {
			const id = req.params.id

			// Open file
			try {
				const size = await storage.size(id)
				const stream = await storage.open(id, 'r')
				const type = stream.file_info.mime_type

				// Close the stream; we don't need to fetch the file (if we haven't
				// already). Then return result.
				stream.destroy()

				res.status(200)
				res.contentType(type)
				res.header('Content-Disposition', 'inline')
				res.header('Content-Transfer-Encoding', 'binary')
				res.header('Accept-Ranges', 'bytes')
				if (size > 0) {
					res.header('Content-Length', size)
				}
				res.send()
			} catch (err) {
				error_handler(res, err, err.code)
			}
		},

		// Put for uploads
		async put(req, res, _next) {
			const id = req.params.id // content id

			// First check if we're the liaison for the name, otherwise we can bail
			// out already.
			const role_addr = runtime.identities.key.address
			const providerId = runtime.storageProviderId
			let dataObject
			try {
				debug('calling checkLiaisonForDataObject')
				dataObject = await runtime.assets.checkLiaisonForDataObject(providerId, id)
				debug('called checkLiaisonForDataObject')
			} catch (err) {
				error_handler(res, err, 403)
				return
			}

			// We'll open a write stream to the backend, but reserve the right to
			// abort upload if the filters don't smell right.
			let stream
			try {
				stream = await storage.open(id, 'w')

				// We don't know whether the filtering occurs before or after the
				// stream was finished, and can only commit if both passed.
				let finished = false
				let accepted = false
				const possibly_commit = () => {
					if (finished && accepted) {
						debug('Stream is finished and passed filters; committing.')
						stream.commit()
					}
				}

				stream.on('file_info', async (info) => {
					try {
						debug('Detected file info:', info)

						// Filter
						const filter_result = filter({}, req.headers, info.mime_type)
						if (200 != filter_result.code) {
							debug('Rejecting content', filter_result.message)
							stream.end()
							res.status(filter_result.code).send({ message: filter_result.message })

							// Reject the content
							await runtime.assets.rejectContent(role_addr, providerId, id)
							return
						}
						debug('Content accepted.')
						accepted = true

						// We may have to commit the stream.
						possibly_commit()
					} catch (err) {
						error_handler(res, err)
					}
				})

				stream.on('finish', () => {
					try {
						finished = true
						possibly_commit()
					} catch (err) {
						error_handler(res, err)
					}
				})

				stream.on('committed', async (hash) => {
					console.log('commited', dataObject)
					try {
						if (hash !== dataObject.ipfs_content_id.toString()) {
							debug('Rejecting content. IPFS hash does not match value in objectId')
							await runtime.assets.rejectContent(role_addr, providerId, id)
							res.status(400).send({ message: "Uploaded content doesn't match IPFS hash" })
							return
						}

						debug('accepting Content')
						await runtime.assets.acceptContent(role_addr, providerId, id)

						debug('creating storage relationship for newly uploaded content')
						// Create storage relationship and flip it to ready.
						const dosr_id = await runtime.assets.createAndReturnStorageRelationship(
							role_addr,
							providerId,
							id
						)

						debug('toggling storage relationship for newly uploaded content')
						await runtime.assets.toggleStorageRelationshipReady(role_addr, providerId, dosr_id, true)

						debug('Sending OK response.')
						res.status(200).send({ message: 'Asset uploaded.' })
					} catch (err) {
						debug(`${err.message}`)
						error_handler(res, err)
					}
				})

				stream.on('error', (err) => error_handler(res, err))
				req.pipe(stream)
			} catch (err) {
				error_handler(res, err)
				return
			}
		},

		// Get content
		async get(req, res, _next) {
			const id = req.params.id
			const download = req.query.download

			// Parse range header
			let ranges
			if (!download) {
				try {
					const range_header = req.headers.range
					ranges = util_ranges.parse(range_header)
				} catch (err) {
					// Do nothing; it's ok to ignore malformed ranges and respond with the
					// full content according to https://www.rfc-editor.org/rfc/rfc7233.txt
				}
				if (ranges && ranges.unit != 'bytes') {
					// Ignore ranges that are not byte units.
					ranges = undefined
				}
			}
			debug('Requested range(s) is/are', ranges)

			// Open file
			try {
				const size = await storage.size(id)
				const stream = await storage.open(id, 'r')

				// Add a file extension to download requests if necessary. If the file
				// already contains an extension, don't add one.
				let send_name = id
				const type = stream.file_info.mime_type
				if (download) {
					let ext = path.extname(send_name)
					if (!ext) {
						ext = stream.file_info.ext
						if (ext) {
							send_name = `${send_name}.${ext}`
						}
					}
				}

				const opts = {
					name: send_name,
					type,
					size,
					ranges,
					download,
				}
				util_ranges.send(res, stream, opts)
			} catch (err) {
				error_handler(res, err, err.code)
			}
		},
	}

	// OpenAPI specs
	doc.get.apiDoc = {
		description: 'Download an asset.',
		operationId: 'assetData',
		tags: ['asset', 'data'],
		parameters: [
			{
				name: 'download',
				in: 'query',
				description: 'Download instead of streaming inline.',
				required: false,
				allowEmptyValue: true,
				schema: {
					type: 'boolean',
					default: false,
				},
			},
		],
		responses: {
			200: {
				description: 'Asset download.',
				content: {
					default: {
						schema: {
							type: 'string',
							format: 'binary',
						},
					},
				},
			},
			default: {
				description: 'Unexpected error',
				content: {
					'application/json': {
						schema: {
							$ref: '#/components/schemas/Error',
						},
					},
				},
			},
		},
	}

	doc.put.apiDoc = {
		description: 'Asset upload.',
		operationId: 'assetUpload',
		tags: ['asset', 'data'],
		requestBody: {
			content: {
				'*/*': {
					schema: {
						type: 'string',
						format: 'binary',
					},
				},
			},
		},
		responses: {
			200: {
				description: 'Asset upload.',
				content: {
					'application/json': {
						schema: {
							type: 'object',
							required: ['message'],
							properties: {
								message: {
									type: 'string',
								},
							},
						},
					},
				},
			},
			default: {
				description: 'Unexpected error',
				content: {
					'application/json': {
						schema: {
							$ref: '#/components/schemas/Error',
						},
					},
				},
			},
		},
	}

	doc.head.apiDoc = {
		description: 'Asset download information.',
		operationId: 'assetInfo',
		tags: ['asset', 'metadata'],
		responses: {
			200: {
				description: 'Asset info.',
			},
			default: {
				description: 'Unexpected error',
				content: {
					'application/json': {
						schema: {
							$ref: '#/components/schemas/Error',
						},
					},
				},
			},
		},
	}

	return doc
}