const npmFetch = require('npm-registry-fetch')
const localeCompare = require('@isaacs/string-locale-compare')('en')
const npa = require('npm-package-arg')
const pacote = require('pacote')
const tufClient = require('@sigstore/tuf')
const { log, output } = require('proc-log')

const sortAlphabetically = (a, b) => localeCompare(a.name, b.name)

class VerifySignatures {
  constructor (tree, filterSet, npm, opts) {
    this.tree = tree
    this.filterSet = filterSet
    this.npm = npm
    this.opts = opts
    this.keys = new Map()
    this.invalid = []
    this.missing = []
    this.checkedPackages = new Set()
    this.auditedWithKeysCount = 0
    this.verifiedSignatureCount = 0
    this.verifiedAttestationCount = 0
    this.exitCode = 0
  }

  async run () {
    const start = process.hrtime.bigint()
    const { default: pMap } = await import('p-map')

    // Find all deps in tree
    const { edges, registries } = this.getEdgesOut(this.tree.inventory.values(), this.filterSet)
    if (edges.size === 0) {
      throw new Error('found no installed dependencies to audit')
    }

    const tuf = await tufClient.initTUF({
      cachePath: this.opts.tufCache,
      retry: this.opts.retry,
      timeout: this.opts.timeout,
    })
    await Promise.all([...registries].map(registry => this.setKeys({ registry, tuf })))

    log.verbose('verifying registry signatures')
    await pMap(edges, (e) => this.getVerifiedInfo(e), { concurrency: 20, stopOnError: true })

    // Didn't find any dependencies that could be verified, e.g. only local deps, missing version, not on a registry etc.
    if (!this.auditedWithKeysCount && !this.verifiedAttestationCount) {
      throw new Error('found no dependencies to audit that were installed from ' +
                      'a supported registry')
    }

    const invalid = this.invalid.sort(sortAlphabetically)
    const missing = this.missing.sort(sortAlphabetically)

    const hasNoInvalidOrMissing = invalid.length === 0 && missing.length === 0

    if (!hasNoInvalidOrMissing) {
      process.exitCode = 1
    }

    if (this.npm.config.get('json')) {
      output.buffer({ invalid, missing })
      return
    }
    const end = process.hrtime.bigint()
    const elapsed = end - start

    const auditedPlural = this.auditedWithKeysCount > 1 ? 's' : ''
    const timing = `audited ${this.auditedWithKeysCount} package${auditedPlural} in ` +
      `${Math.floor(Number(elapsed) / 1e9)}s`
    output.standard(timing)
    output.standard()

    const verifiedBold = this.npm.chalk.bold('verified')
    if (this.verifiedSignatureCount) {
      if (this.verifiedSignatureCount === 1) {
        output.standard(`${this.verifiedSignatureCount} package has a ${verifiedBold} registry signature`)
      } else {
        output.standard(`${this.verifiedSignatureCount} packages have ${verifiedBold} registry signatures`)
      }
      output.standard()
    }

    if (this.verifiedAttestationCount) {
      if (this.verifiedAttestationCount === 1) {
        output.standard(`${this.verifiedAttestationCount} package has a ${verifiedBold} attestation`)
      } else {
        output.standard(`${this.verifiedAttestationCount} packages have ${verifiedBold} attestations`)
      }
      output.standard()
    }

    if (missing.length) {
      const missingClr = this.npm.chalk.redBright('missing')
      if (missing.length === 1) {
        output.standard(`1 package has a ${missingClr} registry signature but the registry is providing signing keys:`)
      } else {
        output.standard(`${missing.length} packages have ${missingClr} registry signatures but the registry is providing signing keys:`)
      }
      output.standard()
      missing.map(m =>
        output.standard(`${this.npm.chalk.red(`${m.name}@${m.version}`)} (${m.registry})`)
      )
    }

    if (invalid.length) {
      if (missing.length) {
        output.standard()
      }
      const invalidClr = this.npm.chalk.redBright('invalid')
      // We can have either invalid signatures or invalid provenance
      const invalidSignatures = this.invalid.filter(i => i.code === 'EINTEGRITYSIGNATURE')
      if (invalidSignatures.length) {
        if (invalidSignatures.length === 1) {
          output.standard(`1 package has an ${invalidClr} registry signature:`)
        } else {
          output.standard(`${invalidSignatures.length} packages have ${invalidClr} registry signatures:`)
        }
        output.standard()
        invalidSignatures.map(i =>
          output.standard(`${this.npm.chalk.red(`${i.name}@${i.version}`)} (${i.registry})`)
        )
        output.standard()
      }

      const invalidAttestations = this.invalid.filter(i => i.code === 'EATTESTATIONVERIFY')
      if (invalidAttestations.length) {
        if (invalidAttestations.length === 1) {
          output.standard(`1 package has an ${invalidClr} attestation:`)
        } else {
          output.standard(`${invalidAttestations.length} packages have ${invalidClr} attestations:`)
        }
        output.standard()
        invalidAttestations.map(i =>
          output.standard(`${this.npm.chalk.red(`${i.name}@${i.version}`)} (${i.registry})`)
        )
        output.standard()
      }

      if (invalid.length === 1) {
        output.standard(`Someone might have tampered with this package since it was published on the registry!`)
      } else {
        output.standard(`Someone might have tampered with these packages since they were published on the registry!`)
      }
      output.standard()
    }
  }

  getEdgesOut (nodes, filterSet) {
    const edges = new Set()
    const registries = new Set()
    for (const node of nodes) {
      for (const edge of node.edgesOut.values()) {
        const filteredOut =
          edge.from
            && filterSet
            && filterSet.size > 0
            && !filterSet.has(edge.from.target)

        if (!filteredOut) {
          const spec = this.getEdgeSpec(edge)
          if (spec) {
            // Prefetch and cache public keys from used registries
            registries.add(this.getSpecRegistry(spec))
          }
          edges.add(edge)
        }
      }
    }
    return { edges, registries }
  }

  async setKeys ({ registry, tuf }) {
    const { host, pathname } = new URL(registry)
    // Strip any trailing slashes from pathname
    const regKey = `${host}${pathname.replace(/\/$/, '')}/keys.json`
    let keys = await tuf.getTarget(regKey)
      .then((target) => JSON.parse(target))
      .then(({ keys: ks }) => ks.map((key) => ({
        ...key,
        keyid: key.keyId,
        pemkey: `-----BEGIN PUBLIC KEY-----\n${key.publicKey.rawBytes}\n-----END PUBLIC KEY-----`,
        expires: key.publicKey.validFor.end || null,
      }))).catch(err => {
        if (err.code === 'TUF_FIND_TARGET_ERROR') {
          return null
        } else {
          throw err
        }
      })

    // If keys not found in Sigstore TUF repo, fall back to registry keys API
    if (!keys) {
      log.warn(`Fetching verification keys using TUF failed.  Fetching directly from ${registry}.`)
      keys = await npmFetch.json('/-/npm/v1/keys', {
        ...this.npm.flatOptions,
        registry,
      }).then(({ keys: ks }) => ks.map((key) => ({
        ...key,
        pemkey: `-----BEGIN PUBLIC KEY-----\n${key.key}\n-----END PUBLIC KEY-----`,
      }))).catch(err => {
        if (err.code === 'E404' || err.code === 'E400') {
          return null
        } else {
          throw err
        }
      })
    }

    if (keys) {
      this.keys.set(registry, keys)
    }
  }

  getEdgeType (edge) {
    return edge.optional ? 'optionalDependencies'
      : edge.peer ? 'peerDependencies'
      : edge.dev ? 'devDependencies'
      : 'dependencies'
  }

  getEdgeSpec (edge) {
    let name = edge.name
    try {
      name = npa(edge.spec).subSpec.name
    } catch {
      // leave it as edge.name
    }
    try {
      return npa(`${name}@${edge.spec}`)
    } catch {
      // Skip packages with invalid spec
    }
  }

  buildRegistryConfig (registry) {
    const keys = this.keys.get(registry) || []
    const parsedRegistry = new URL(registry)
    const regKey = `//${parsedRegistry.host}${parsedRegistry.pathname}`
    return {
      [`${regKey}:_keys`]: keys,
    }
  }

  getSpecRegistry (spec) {
    return npmFetch.pickRegistry(spec, this.npm.flatOptions)
  }

  getValidPackageInfo (edge) {
    const type = this.getEdgeType(edge)
    // Skip potentially optional packages that are not on disk, as these could
    // be omitted during install
    if (edge.error === 'MISSING' && type !== 'dependencies') {
      return
    }

    const spec = this.getEdgeSpec(edge)
    // Skip invalid version requirements
    if (!spec) {
      return
    }
    const node = edge.to || edge
    const { version } = node.package || {}

    if (node.isWorkspace || // Skip local workspaces packages
        !version || // Skip packages that don't have an installed version, e.g. optional dependencies
        !spec.registry) { // Skip if not from registry, e.g. git package
      return
    }

    for (const omitType of this.npm.config.get('omit')) {
      if (node[omitType]) {
        return
      }
    }

    return {
      name: spec.name,
      version,
      type,
      location: node.location,
      registry: this.getSpecRegistry(spec),
    }
  }

  async verifySignatures (name, version, registry) {
    const {
      _integrity: integrity,
      _signatures,
      _attestations,
      _resolved: resolved,
    } = await pacote.manifest(`${name}@${version}`, {
      verifySignatures: true,
      verifyAttestations: true,
      ...this.buildRegistryConfig(registry),
      ...this.npm.flatOptions,
    })
    const signatures = _signatures || []
    const result = {
      integrity,
      signatures,
      attestations: _attestations,
      resolved,
    }
    return result
  }

  async getVerifiedInfo (edge) {
    const info = this.getValidPackageInfo(edge)
    if (!info) {
      return
    }
    const { name, version, location, registry, type } = info
    if (this.checkedPackages.has(location)) {
      // we already did or are doing this one
      return
    }
    this.checkedPackages.add(location)

    // We only "audit" or verify the signature, or the presence of it, on packages whose registry returns signing keys
    const keys = this.keys.get(registry) || []
    if (keys.length) {
      this.auditedWithKeysCount += 1
    }

    try {
      const { integrity, signatures, attestations, resolved } = await this.verifySignatures(
        name, version, registry
      )

      // Currently we only care about missing signatures on registries that provide a public key
      // We could make this configurable in the future with a strict/paranoid mode
      if (signatures.length) {
        this.verifiedSignatureCount += 1
      } else if (keys.length) {
        this.missing.push({
          integrity,
          location,
          name,
          registry,
          resolved,
          version,
        })
      }

      // Track verified attestations separately to registry signatures, as all packages on registries with signing keys are expected to have registry signatures, but not all packages have provenance and publish attestations.
      if (attestations) {
        this.verifiedAttestationCount += 1
      }
    } catch (e) {
      if (e.code === 'EINTEGRITYSIGNATURE' || e.code === 'EATTESTATIONVERIFY') {
        this.invalid.push({
          code: e.code,
          message: e.message,
          integrity: e.integrity,
          keyid: e.keyid,
          location,
          name,
          registry,
          resolved: e.resolved,
          signature: e.signature,
          predicateType: e.predicateType,
          type,
          version,
        })
      } else {
        throw e
      }
    }
  }
}

module.exports = VerifySignatures
