#!@GUILE@ --no-auto-compile
-*- scheme -*-
-*- geiser-scheme-implementation: guile -*-
!#
;;; Nar Herder
;;;
;;; Copyright © 2020 Christopher Baines <mail@cbaines.net>
;;;
;;; This file is part of the nar-herder.
;;;
;;; The Nar Herder 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.
;;;
;;; The Nar Herder 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 the guix-data-service.  If not, see
;;; <http://www.gnu.org/licenses/>.

(setvbuf (current-output-port) 'line)
(setvbuf (current-error-port) 'line)

(let ((columns (string->number (or (getenv "COLUMNS") ""))))
  (setenv "COLUMNS"
          (number->string
           (if columns
               (max 256 columns)
               256))))

(use-modules (srfi srfi-1)
             (srfi srfi-19)
             (srfi srfi-37)
             (srfi srfi-43)
             (ice-9 ftw)
             (ice-9 match)
             (ice-9 format)
             (ice-9 threads)
             (ice-9 suspendable-ports)
             (web uri)
             (web client)
             (web response)
             (oop goops)
             (logging logger)
             (logging port-log)
             (prometheus)
             (fibers)
             (fibers conditions)
             (fibers web server)
             ((guix ui) #:select (read/eval string->duration))
             (guix store)
             (guix progress)
             (guix narinfo)
             (guix derivations)
             ((guix store) #:select (store-path-hash-part))
             ((guix build utils) #:select (dump-port))
             ((guix build syscalls) #:select (set-thread-name))
             (nar-herder utils)
             (nar-herder database)
             (nar-herder recent-changes)
             (nar-herder cached-compression)
             (nar-herder storage)
             (nar-herder mirror)
             (nar-herder server))

(install-suspendable-ports!)

(define %valid-log-levels
  '(DEBUG INFO WARN ERROR))

(define %base-options
  (list (option '("database") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'database
                              arg
                              result)))
        (option '("database-dump") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'database-dump
                              arg
                              result)))
        (option '("storage") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'storage
                              arg
                              (alist-delete 'storage result))))

        (option '("log-level") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'log-level
                              (let ((level (string->symbol (string-upcase arg))))
                                (if (member level %valid-log-levels)
                                    level
                                    (error
                                     (simple-format #f "unknown log level ~A\nvalid levels are: ~A\n"
                                                    level
                                                    %valid-log-levels))))
                              (alist-delete 'log-level result))))))

(define %base-option-defaults
  ;; Alist of default option values
  `((database . ,(string-append (getcwd) "/nar_herder.db"))
    (database-dump . ,(string-append (getcwd) "/nar_herder_dump.db"))

    (log-level                            . DEBUG)))

(define %import-options
  (list (option '("tag") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'tags
                              (cons (match (string-split arg #\=)
                                      ((key value)
                                       (cons key value)))
                                    (or (assq-ref result 'tags)
                                        '()))
                              (alist-delete 'tags result))))
        (option '("ensure-references-exist") #f #f
                (lambda (opt name _ result)
                  (alist-cons 'ensure-references-exist #t result)))))

(define %import-options-defaults
  '())

(define %server-options
  (list (option '("port") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'port
                              (string->number arg)
                              (alist-delete 'port result))))
        (option '("host") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'host
                              arg
                              (alist-delete 'host result))))
        (option '("pid-file") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'pid-file
                              arg
                              (alist-delete 'pid-file result))))
        (option '("storage-limit") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'storage-limit
                              (if (string=? arg "none")
                                  "none"
                                  (string->number arg))
                              (alist-delete 'storage-limit result))))

        ;; stored-on=https://other-nar-herder-server
        ;; stored-on=https://other-nar-herder-server&stored-on=https://different-server
        (option '("storage-nar-removal-criteria") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'storage-nar-removal-criteria
                              (match (string-split arg #\=)
                                ((sym rest)
                                 (list (string->symbol sym)
                                       (call-with-input-string rest read))))
                              result)))

        (option '("enable-cached-compression") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'cached-compression
                              (match (string-split arg #\:)
                                ((type)
                                 `((type . ,(string->symbol type))))
                                ((type level)
                                 `((type  . ,(string->symbol type))
                                   (level . ,(string->number level)))))
                              result)))

        (option '("cached-compression-directory") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'cached-compression-directory
                              (match (string-split arg #\=)
                                ((type directory)
                                 (cons (string->symbol type)
                                       (canonicalize-path directory))))
                              result)))

        (option '("cached-compression-directory-max-size") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'cached-compression-directory-max-size
                              (match (string-split arg #\=)
                                ((type size)
                                 (cons (string->symbol type)
                                       (string->number size))))
                              result)))

        (option '("cached-compression-min-uses") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'cached-compression-min-uses
                              (string->number arg)
                              (alist-delete 'cached-compression-min-uses
                                            result))))

        (option '("cached-compression-workers") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'cached-compression-workers
                              (string->number arg)
                              result)))

        (option '("cached-compression-nar-source") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'cached-compression-nar-source
                              arg
                              (alist-delete 'cached-compression-nar-source
                                            result))))

        (option '("ttl") #t #f
                (lambda (opt name arg result)
                  (let ((duration (string->duration arg)))
                    (unless duration
                      (simple-format (current-error-port)
                                     "~A: invalid duration\n"
                                     arg)
                      (exit 1))
                    (alist-cons 'narinfo-ttl (time-second duration)
                                result))))
        (option '("negative-ttl") #t #f
                (lambda (opt name arg result)
                  (let ((duration (string->duration arg)))
                    (unless duration
                      (simple-format (current-error-port)
                                     "~A: invalid duration\n"
                                     arg)
                      (exit 1))
                    (alist-cons 'narinfo-negative-ttl (time-second duration)
                                result))))

        (option '("recent-changes-limit") #t #f
                (lambda (opt name arg result)+
                  (alist-cons 'recent-changes-limit
                              (string->number arg)
                              (alist-delete 'recent-changes-limit result))))

        (option '("mirror") #t #f
                (lambda (opt name arg result)
                  (alist-cons 'mirror
                              arg
                              (alist-delete 'mirror result))))))

(define %server-option-defaults
  '((port                                 . 8080)
    (host                                 . "0.0.0.0")

    (storage-limit                        . "none")

    (cached-compression-workers           . 2)
    (cached-compression-min-uses          . 3)

    (recent-changes-limit                 . 32768)))

(define %check-options
  (list))

(define %check-option-defaults
  '())

(define (parse-options options defaults args)
  (args-fold
   args options
   (lambda (opt name arg result)
     (error "unrecognized option" name))
   (lambda (arg result)
     (alist-cons
      'arguments
      (cons arg
            (or (assoc-ref result 'arguments)
                '()))
      (alist-delete 'arguments result)))
   defaults))

(match (cdr (program-arguments))
  (("import" rest ...)
   (let* ((opts (parse-options (append %base-options
                                       %import-options)
                               (append %base-option-defaults
                                       %import-options-defaults)
                               rest))
          (metrics-registry
           (make-metrics-registry #:namespace
                                  "narherder"))
          (database (setup-database
                     (assq-ref opts 'database)
                     metrics-registry)))
     (let* ((narinfos
             (append-map
              (lambda (file-or-dir)
                (let ((s (stat file-or-dir)))
                  (match (stat:type s)
                    ('regular (list file-or-dir))
                    ('directory
                     (let ((dir file-or-dir))
                       (map
                        (lambda (nar-filename)
                          (string-append dir
                                         (if (string-suffix? "/" dir)
                                             ""
                                             "/")
                                         nar-filename))
                        (scandir file-or-dir
                                 (lambda (name)
                                   (string-suffix? ".narinfo" name)))))))))
              (assq-ref opts 'arguments)))
            (len (length narinfos))
            (progress
             (progress-reporter/bar len
                                    (format #f "importing ~a narinfos"
                                            len)
                                    (current-error-port))))

       (call-with-progress-reporter progress
         (lambda (report)
           (database-call-with-transaction
            database
            (lambda (db)
              (let ((read-narinfos
                     (map
                      (lambda (narinfo-file)
                        (let ((narinfo
                               (call-with-input-file narinfo-file
                                 (lambda (port)
                                   ;; Set url to a dummy value as this doesn't
                                   ;; matter
                                   (read-narinfo port
                                                 "https://narherderdummyvalue")))))

                          (database-insert-narinfo
                           database
                           narinfo
                           #:tags (or (assq-ref opts 'tags)
                                      '()))

                          (report)

                          narinfo))
                      narinfos)))

                (when (assq-ref opts 'ensure-references-exist)
                  (for-each
                   (lambda (narinfo)
                     (let ((self-reference
                            (store-path-base
                             (narinfo-path narinfo))))
                       (for-each
                        (lambda (reference)
                          (when (and
                                 (not
                                  (string=? reference self-reference))
                                 (not
                                  (database-select-narinfo-by-hash
                                   database
                                   (string-take reference 32))))
                            (error
                             (simple-format (current-error-port)
                                            "missing reference to ~A\n"
                                            reference))))
                        (narinfo-references narinfo))))
                   read-narinfos))))))))))
  (("remove" rest ...)
   (let* ((opts (parse-options %base-options
                               %base-option-defaults
                               rest))
          (metrics-registry
           (make-metrics-registry #:namespace
                                  "narherder"))
          (database (setup-database
                     (assq-ref opts 'database)
                     metrics-registry))
          (lgr (make <logger>))
          (port-log (make <port-log>
                      #:port (current-output-port)
                      #:formatter
                      (lambda (lvl time str)
                        (format #f "~a (~5a): ~a~%"
                                (strftime "%F %H:%M:%S" (localtime time))
                                lvl
                                str)))))

     (add-handler! lgr port-log)
     (open-log! lgr)
     (set-default-logger! lgr)

     (for-each
      (lambda (store-path)
        (log-msg 'INFO "removing " store-path)

        (if (assq-ref opts 'storage)
            (begin
              ;; Removing the files here isn't ideal, since the servers
              ;; metrics won't be updated until the next get-nar-files call,
              ;; but it avoids extra complexity in trying to have the server
              ;; delete the files.
              (remove-nar-files-by-hash
               database
               (assq-ref opts 'storage)
               metrics-registry
               (store-path-hash-part store-path)
               #:error-unless-files-to-remove? #f))
            (log-msg
             'WARN "no --storage set, so just removing from the database"))

        (let ((removed? (database-remove-narinfo database store-path)))
          (unless removed?
            (log-msg 'WARN store-path " not found to remove"))))
      (assq-ref opts 'arguments))))
  (("check" rest ...)
   (let* ((opts (parse-options (append %base-options
                                       %check-options)
                               (append %base-option-defaults
                                       %check-option-defaults)
                               rest))
          (lgr (make <logger>))
          (port-log (make <port-log>
                      #:port (current-output-port)
                      #:formatter
                      (lambda (lvl time str)
                        (format #f "~a (~5a): ~a~%"
                                (strftime "%F %H:%M:%S" (localtime time))
                                lvl
                                str))))
          (metrics-registry (make-metrics-registry
                             #:namespace
                             "narherder")))

     (add-handler! lgr port-log)
     (open-log! lgr)
     (set-default-logger! lgr)

     (let ((log-level (assq-ref opts 'log-level)))
       (let loop ((levels %valid-log-levels))
         (when (and (not (null? levels))
                    (not (eq? (car levels) log-level)))
           (disable-log-level! lgr (car levels))
           (loop (cdr levels)))))

     (let* ((database (setup-database (assq-ref opts 'database)
                                      metrics-registry))
            (canonical-storage (and=> (assq-ref opts 'storage)
                                      canonicalize-path)))

       (check-storage database
                      canonical-storage
                      metrics-registry))))
  (("run-server" rest ...)
   (simple-format (current-error-port) "locale is ~A\n" (check-locale!))

   (let* ((opts (parse-options (append %base-options
                                       %server-options)
                               (append %base-option-defaults
                                       %server-option-defaults)
                               rest))
          (unknown-arguments
           (or (assq-ref opts 'arguments)
               '()))
          (lgr (make <logger>))
          (port-log (make <port-log>
                      #:port (current-output-port)
                      #:formatter
                      (lambda (lvl time str)
                        (format #f "~a (~5a): ~a~%"
                                (strftime "%F %H:%M:%S" (localtime time))
                                lvl
                                str))))
          (metrics-registry (make-metrics-registry
                             #:namespace
                             "narherder")))

     (define (download-database)
       (let ((database-uri
              (string->uri
               (string-append (assq-ref opts 'mirror)
                              "/latest-database-dump"))))
         (with-fibers-port-timeouts
          (lambda ()
            (call-with-values
                (lambda ()
                  (simple-format (current-error-port)
                                 "starting downloading the database\n")
                  (http-get database-uri
                            #:decode-body? #f
                            #:streaming? #t))
              (lambda (response body)
                (when (not (= (response-code response) 200))
                  (error "unable to fetch database from mirror"))

                (let* ((reporter (progress-reporter/file
                                  (uri->string database-uri)
                                  (response-content-length response)
                                  (current-error-port)))
                       (port
                        (progress-report-port
                         reporter
                         body
                         #:download-size (response-content-length response))))

                  (call-with-output-file (assq-ref opts 'database)
                    (lambda (output-port)
                      (dump-port port output-port)))

                  (close-port port))

                (simple-format (current-error-port)
                               "finished downloading the database\n"))))
          #:timeout 30)))

     (add-handler! lgr port-log)
     (open-log! lgr)
     (set-default-logger! lgr)

     (let ((log-level (assq-ref opts 'log-level)))
       (let loop ((levels %valid-log-levels))
         (when (and (not (null? levels))
                    (not (eq? (car levels) log-level)))
           (disable-log-level! lgr (car levels))
           (loop (cdr levels)))))

     (unless (null? unknown-arguments)
       (simple-format (current-error-port)
                      "unknown arguments: ~A\n"
                      unknown-arguments)
       (exit 1))

     (unless (or (assq-ref opts 'mirror)
                 (assq-ref opts 'storage))
       (simple-format (current-error-port)
                      "error: you must specify --mirror or --storage\n")
       (exit 1))

     (and=> (assq-ref opts 'pid-file)
            (lambda (pid-file)
              (call-with-output-file pid-file
                (lambda (port)
                  (simple-format port "~A\n" (getpid))))))

     (and=>
      (assq-ref opts 'mirror)
      (lambda (mirror)
        (let ((database-file (assq-ref opts 'database)))
          (if (file-exists? database-file)
              (begin
                ;; TODO Open the database, and check if the
                ;; latest changes in the database are visible on
                ;; the source to mirror. If they're not, then
                ;; delete the database and download it to get
                ;; back in sync

                #f)
              (download-database)))))

     (let* ((database (setup-database (assq-ref opts 'database)
                                      metrics-registry))
            (canonical-storage (and=> (assq-ref opts 'storage)
                                      canonicalize-path))

            (enabled-cached-compressions
             (let ((explicit-cached-compression-directories
                    (filter-map
                     (match-lambda
                       (('cached-compression-directory . details) details)
                       (_ #f))
                     opts))
                   (cached-compression-directories-max-sizes
                    (filter-map
                     (match-lambda
                       (('cached-compression-directory-max-size . details) details)
                       (_ #f))
                     opts)))
               (filter-map
                (match-lambda
                  (('cached-compression . details)
                   (let ((compression
                          (assq-ref details 'type)))
                     (cons compression
                           `(,@(alist-delete 'type details)
                             (directory
                              . ,(or (assq-ref explicit-cached-compression-directories
                                               compression)
                                     (simple-format #f "/var/cache/nar-herder/nar/~A"
                                                    compression)))
                             (directory-max-size
                              . ,(assq-ref cached-compression-directories-max-sizes
                                           compression))))))
                  (_ #f))
                opts)))

            (cached-compression-min-uses
             (assq-ref opts 'cached-compression-min-uses))

            (maybe-trigger-creation-of-compressed-nars
             (if (null? enabled-cached-compressions)
                 #f
                 (make-maybe-trigger-creation-of-compressed-nars
                  database
                  metrics-registry
                  (or (assq-ref opts 'cached-compression-nar-source)
                      canonical-storage)
                  enabled-cached-compressions
                  cached-compression-min-uses
                  #:cached-compression-workers
                  (assq-ref opts 'cached-compression-workers)))))

       (if (string=? (assq-ref opts 'database-dump)
                     "disabled")
           (log-msg 'INFO "database dump disabled")
           (when (not (file-exists? (assq-ref opts 'database-dump)))
             (log-msg 'INFO "dumping database...")
             (dump-database database (assq-ref opts 'database-dump))))

       (let ((finished? (make-condition)))
         (call-with-new-thread
          (lambda ()
            (catch 'system-error
              (lambda ()
                (set-thread-name "maintenance"))
              (const #t))

            (run-fibers
             (lambda ()
               (start-recent-change-removal-and-database-dump-fiber
                database
                (let ((filename (assq-ref opts 'database-dump)))
                  (if (string=? filename "disabled")
                      #f
                      filename))
                (* 24 3600)                     ; 24 hours
                (assq-ref opts 'recent-changes-limit))

               (and=> (assq-ref opts 'mirror)
                      (lambda (mirror)
                        (start-fetch-changes-fiber database
                                                   canonical-storage
                                                   mirror
                                                   metrics-registry)

                        (when (assq-ref opts 'storage)
                          (start-mirroring-fiber database
                                                 mirror
                                                 (assq-ref opts 'storage-limit)
                                                 canonical-storage
                                                 metrics-registry))))


               (let ((nar-removal-criteria
                      (filter-map
                       (match-lambda
                         ((key . val)
                          (if (eq? key 'storage-nar-removal-criteria)
                              val
                              #f)))
                       opts)))
                 (when (and (assq-ref opts 'storage)
                            (number? (assq-ref opts 'storage-limit))
                            (not (null? nar-removal-criteria)))
                   (start-nar-removal-fiber database
                                            canonical-storage
                                            (assq-ref opts 'storage-limit)
                                            metrics-registry
                                            nar-removal-criteria)))

               (wait finished?))
             #:hz 0
             #:parallelism 1)))

         (call-with-sigint
          (lambda ()
            (run-fibers
             (lambda ()
               (log-msg 'INFO "starting server, listening on "
                        (assq-ref opts 'host) ":" (assq-ref opts 'port))

               (run-server/patched
                (make-request-handler database
                                      canonical-storage
                                      #:ttl (assq-ref opts 'narinfo-ttl)
                                      #:negative-ttl (assq-ref opts 'narinfo-negative-ttl)
                                      #:logger lgr
                                      #:metrics-registry metrics-registry
                                      #:maybe-trigger-creation-of-compressed-nars
                                      maybe-trigger-creation-of-compressed-nars)
                #:host (assq-ref opts 'host)
                #:port (assq-ref opts 'port))

               (wait finished?))
             #:hz 0
             #:parallelism 4))
          finished?))))))