;;;; http.scm -- HTTP API
;;; Copyright © 2016 Mathieu Lirzin <mthl@gnu.org>
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2018 Clément Lassieur <clement@lassieur.org>
;;; Copyright © 2018 Tatiana Sholokhova <tanja201396@gmail.com>
;;; Copyright © 2019 Ricardo Wurmus <rekado@elephly.net>
;;;
;;; This file is part of Cuirass.
;;;
;;; Cuirass 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.
;;;
;;; Cuirass 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 Cuirass.  If not, see <http://www.gnu.org/licenses/>.

(define-module (cuirass http)
  #:use-module (cuirass config)
  #:use-module (cuirass database)
  #:use-module (cuirass utils)
  #:use-module (cuirass logging)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-26)
  #:use-module (ice-9 binary-ports)
  #:use-module (ice-9 match)
  #:use-module (json)
  #:use-module (web request)
  #:use-module (web response)
  #:use-module ((web server) #:hide (run-server))
  #:use-module (web uri)
  #:use-module (fibers)
  #:use-module (fibers channels)
  #:use-module (sxml simple)
  #:use-module (cuirass templates)
  #:use-module (guix utils)
  #:use-module (guix build union)
  #:export (run-cuirass-server))

(define %static-directory
  ;; Define to the static file directory.
  (make-parameter (string-append
                   (or (getenv "CUIRASS_DATADIR")
                       (string-append %datadir "/" %package))
                   "/static")))

(define %page-size 10)

(define %file-mime-types
  '(("css" . (text/css))
    ("otf" . (font/otf))
    ("woff" . (font/woff))
    ("js"  . (text/javascript))
    ("png" . (image/png))
    ("gif" . (image/gif))
    ("html" . (text/html))))

(define %file-white-list
  '("css/bootstrap.css"
    "css/open-iconic-bootstrap.css"
    "fonts/open-iconic.otf"
    "fonts/open-iconic.woff"
    "images/logo.png"))

(define (build->hydra-build build)
  "Convert BUILD to an assoc list matching hydra API format."
  (define (bool->int bool)
    (if bool 1 0))

  (define finished?
    (not (memv (assq-ref build #:status)
               (list (build-status scheduled)
                     (build-status started)))))

  `((#:id . ,(assq-ref build #:id))
    (#:jobset . ,(assq-ref build #:specification))
    (#:job . ,(assq-ref build #:job-name))

    ;; Hydra's API uses "timestamp" as the time of the last useful event for
    ;; that build: evaluation or completion.
    (#:timestamp . ,(if finished?
                        (assq-ref build #:stoptime)
                        (assq-ref build #:timestamp)))

    (#:starttime . ,(assq-ref build #:starttime))
    (#:stoptime . ,(assq-ref build #:stoptime))
    (#:derivation . ,(assq-ref build #:derivation))
    (#:buildoutputs . ,(assq-ref build #:outputs))
    (#:system . ,(assq-ref build #:system))
    (#:nixname . ,(assq-ref build #:nix-name))
    (#:buildstatus . ,(assq-ref build #:status))
    (#:busy . ,(bool->int (eqv? (build-status started)
                                (assq-ref build #:status))))
    (#:priority . 0)
    (#:finished . ,(bool->int finished?))
    (#:buildproducts . #nil)
    (#:releasename . #nil)
    (#:buildinputs_builds . #nil)))

(define (handle-build-request build-id)
  "Retrieve build identified by BUILD-ID over the database and convert it to
hydra format. Return #f is not build was found."
  (let ((build (db-get-build build-id)))
    (and=> build build->hydra-build)))

(define (handle-builds-request filters)
  "Retrieve all builds matched by FILTERS in the database and convert them to
Hydra format."
  (let ((builds (with-time-logging "builds request"
                                   (db-get-builds filters))))
    (map build->hydra-build builds)))

(define (handle-builds-search-request filters)
  "Retrieve all builds matched by FILTERS in the database and convert them to
Hydra format."
  (let ((builds (with-time-logging "builds search request"
                                   (db-get-builds-by-search filters))))
    (map build->hydra-build builds)))

(define (request-parameters request)
  "Parse the REQUEST query parameters and return them under the form
  '((parameter . value) ...)."
  (let* ((uri (request-uri request))
         (query (uri-query uri)))
    (if query
        (map (lambda (param)
               (match (string-split param #\=)
                 ((key param)
                  (let ((key-symbol (string->symbol key)))
                    (cons key-symbol
                          (match key-symbol
                            ('id (string->number param))
                            ('nr (string->number param))
                            (_   param)))))))
             (string-split query #\&))
        '())))


;;;
;;; Web server.
;;;
;;; The api is derived from the hydra one. It is partially described here :
;;;
;;; https://github.com/NixOS/hydra/blob/master/doc/manual/api.xml
;;;

(define (request-path-components request)
  (split-and-decode-uri-path (uri-path (request-uri request))))

(define (url-handler request body)

  (define* (respond response #:key body)
    (values response body #f))

  (define-syntax-rule (respond-json body ...)
    (respond '((content-type . (application/json)))
             #:body body ...))

  (define-syntax-rule (respond-text body ...)
    (respond '((content-type . (text/plain)))
             #:body body ...))

  (define-syntax-rule (respond-json-with-error error-code message)
    (respond
     (build-response #:headers '((content-type . (application/json)))
                     #:code error-code)
     #:body
     (object->json-string
      `((error . ,message)))))

  (define* (respond-html body #:key code)
    (respond
     (let ((content-type '((content-type . (application/xhtml+xml)))))
       (if code
           (build-response #:headers content-type #:code code)
           content-type))
     #:body
     (lambda (port)
       (format
        port "<!DOCTYPE html PUBLIC ~s ~s>"
        "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd")
       (sxml->xml body port))))

  (define (respond-static-file path)
    ;; PATH is a list of path components
    (let ((file-name (string-join path "/"))
          (file-path (string-join (cons* (%static-directory) path) "/")))
      (if (and (member file-name %file-white-list)
               (file-exists? file-path)
               (not (file-is-directory? file-path)))
          (respond `((content-type . ,(assoc-ref %file-mime-types
                                                 (file-extension file-path))))
                   #:body (call-with-input-file file-path get-bytevector-all))
          (respond-not-found file-name))))

  (define (respond-build-not-found build-id)
    (respond-json-with-error
     404
     (format #f "Build with ID ~a doesn't exist." build-id)))

  (define (respond-html-eval-not-found eval-id)
    (respond-html
     (html-page "Page not found"
                (format #f "Evaluation with ID ~a doesn't exist." eval-id)
                '())
     #:code 404))

  (define (respond-build-log-not-found build)
    (let ((drv (assq-ref build #:derivation)))
      (respond-json-with-error
       404
       (format #f "The build log of derivation ~a is not available." drv))))

  (define (respond-not-found resource_name)
    (respond (build-response #:code 404)
             #:body (string-append "Resource not found: "
                                   resource_name)))

  (log-message "~a ~a" (request-method request)
               (uri-path (request-uri request)))

  ;; Reject OPTIONS, POST, etc.
  (match (if (eq? 'GET (request-method request))
             (request-path-components request)
             'method-not-allowed)
    (((or "jobsets" "specifications") . rest)
     (respond-json (object->json-string (db-get-specifications))))
    (("build" build-id)
     (let ((hydra-build (handle-build-request (string->number build-id))))
       (if hydra-build
           (respond-json (object->json-string hydra-build))
           (respond-build-not-found build-id))))
    (("build" build-id "details")
     (let ((build (db-get-build (string->number build-id))))
       (if build
           (respond-html
            (html-page (string-append "Build " build-id)
                       (build-details build)
                       `(((#:name . ,(assq-ref build #:specification))
                          (#:link . ,(string-append "/jobset/" (assq-ref build #:specification)))))))
           (respond-build-not-found build-id))))
    (("build" build-id "log" "raw")
     (let ((build (db-get-build (string->number build-id))))
       (if build
           (match (assq-ref build #:outputs)
             (((_ (#:path . (? string? output))) _ ...)
              ;; Redirect to a /log URL, which is assumed to be served
              ;; by 'guix publish'.
              (let ((uri (string->uri-reference
                          (string-append "/log/"
                                         (basename output)))))
                (respond (build-response #:code 302
                                         #:headers `((location . ,uri)))
                         #:body "")))
             (()
              ;; Not entry for BUILD-ID in the 'Outputs' table.
              (respond-json-with-error
               500
               (format #f "Outputs of build ~a are unknown." build-id)))
             (#f
              (respond-build-not-found build-id)))
           (respond-build-not-found build-id))))
    (("api" "evaluations")
     (let* ((params (request-parameters request))
            ;; 'nr parameter is mandatory to limit query size.
            (nr (assq-ref params 'nr)))
       (if nr
           (respond-json (object->json-string (db-get-evaluations nr)))
           (respond-json-with-error 500 "Parameter not defined!"))))
    (("api" "latestbuilds")
     (let* ((params (request-parameters request))
            ;; 'nr parameter is mandatory to limit query size.
            (valid-params? (assq-ref params 'nr)))
       (if valid-params?
           ;; Limit results to builds that are "done".
           (respond-json
            (object->json-string
             (handle-builds-request `((status . done)
                                      ,@params
                                      (order . finish-time)))))
           (respond-json-with-error 500 "Parameter not defined!"))))
    (("api" "queue")
     (let* ((params (request-parameters request))
            ;; 'nr parameter is mandatory to limit query size.
            (valid-params? (assq-ref params 'nr)))
       (if valid-params?
           (respond-json
            (object->json-string
             ;; Use the 'status+submission-time' order so that builds in
             ;; 'running' state appear before builds in 'scheduled' state.
             (handle-builds-request `((status . pending)
                                      ,@params
                                      (order . status+submission-time)))))
           (respond-json-with-error 500 "Parameter not defined!"))))
    ('()
     (respond-html (html-page
                    "Cuirass"
                    (specifications-table (db-get-specifications))
                    '())))

    (("jobset" name)
     (respond-html
      (let* ((evaluation-id-max (db-get-evaluations-id-max name))
             (evaluation-id-min (db-get-evaluations-id-min name))
             (params (request-parameters request))
             (border-high (assq-ref params 'border-high))
             (border-low (assq-ref params 'border-low))
             (evaluations (db-get-evaluations-build-summary name
                                                            %page-size
                                                            border-low
                                                            border-high)))
        (html-page name (evaluation-info-table name
                                               evaluations
                                               evaluation-id-min
                                               evaluation-id-max)
                   `(((#:name . ,name)
                      (#:link . ,(string-append "/jobset/" name))))))))

    (("eval" id)
     (let* ((params (request-parameters request))
            (status (assq-ref params 'status))
            (builds-id-max (db-get-builds-max id status))
            (builds-id-min (db-get-builds-min id status))
            (border-high-time (assq-ref params 'border-high-time))
            (border-low-time (assq-ref params 'border-low-time))
            (border-high-id (assq-ref params 'border-high-id))
            (border-low-id (assq-ref params 'border-low-id))
            (specification (db-get-evaluation-specification id)))
       (if specification
           (respond-html
            (html-page
             "Evaluation"
             `((p (@ (class "lead"))
                  ,(format #f "~@[~a~] ~:[B~;b~]uilds of evaluation #~a"
                           (and=> status string-capitalize)
                           status
                           id))
               (ul (@ (class "nav nav-tabs"))
                   (li (@ (class "nav-item"))
                       (a (@ (class ,(string-append "nav-link "
                                                    (match status
                                                      (#f "active")
                                                      (_ ""))))
                             (href "?all="))
                          "All"))
                   (li (@ (class "nav-item"))
                       (a (@ (class ,(string-append "nav-link "
                                                    (match status
                                                      ("pending" "active")
                                                      (_ ""))))
                             (href "?status=pending"))
                          (span (@ (class "oi oi-clock text-warning")
                                   (title "Scheduled")
                                   (aria-hidden "true"))
                                "")
                          " Scheduled"))
                   (li (@ (class "nav-item"))
                       (a (@ (class ,(string-append "nav-link "
                                                    (match status
                                                      ("succeeded" "active")
                                                      (_ ""))))
                             (href "?status=succeeded"))
                          (span (@ (class "oi oi-check text-success")
                                (title "Succeeded")
                                (aria-hidden "true"))
                             "")
                          " Succeeded"))
                   (li (@ (class "nav-item"))
                       (a (@ (class ,(string-append "nav-link "
                                                    (match status
                                                      ("failed" "active")
                                                      (_ ""))))
                             (href "?status=failed"))
                          (span (@ (class "oi oi-x text-danger")
                                   (title "Failed")
                                   (aria-hidden "true"))
                                "")
                          " Failed"))
                   (li (@ (class "nav-item"))
                       (a (@ (class ,(string-append "nav-link "
                                                    (match status
                                                      ("failed-dependency" "active")
                                                      (_ ""))))
                             (href "?status=failed-dependency"))
                          (span (@ (class "oi oi-warning text-danger")
                                   (title "Dependency failed")
                                   (aria-hidden "true"))
                                "")
                          " Dependency failed"))
                   (li (@ (class "nav-item"))
                       (a (@ (class ,(string-append "nav-link "
                                                    (match status
                                                      ("failed-other" "active")
                                                      (_ ""))))
                             (href "?status=failed-other"))
                          (span (@ (class "oi oi-x text-danger")
                                   (title "Failed")
                                   (aria-hidden "true"))
                                "")
                          " Other failed"))
                   (li (@ (class "nav-item"))
                       (a (@ (class ,(string-append "nav-link "
                                                    (match status
                                                      ("canceled" "active")
                                                      (_ ""))))
                             (href "?status=canceled"))
                          (span (@ (class "oi oi-question-mark text-warning")
                                   (title "Canceled")
                                   (aria-hidden "true"))
                                "")
                          " Canceled")))
               (div (@ (class "tab-content pt-3"))
                    (div (@ (class "tab-pane show active"))
                         ,(build-eval-table
                           id
                           (handle-builds-request
                            `((evaluation . ,id)
                              (status . ,(and=> status string->symbol))
                              (nr . ,%page-size)
                              (order . finish-time+build-id)
                              (border-high-time . ,border-high-time)
                              (border-low-time . ,border-low-time)
                              (border-high-id . ,border-high-id)
                              (border-low-id . ,border-low-id)))
                           builds-id-min
                           builds-id-max
                           status))))
             `(((#:name . ,specification)
                (#:link . ,(string-append "/jobset/" specification)))
               ((#:name . ,(string-append "Evaluation " id))
                (#:link . ,(string-append "/eval/" id))))))
           (respond-html-eval-not-found id))))

    (("search")
     (let* ((params (request-parameters request))
            (query (and=> (assq-ref params 'query) uri-decode))
            (builds-id-min (and=> query db-get-builds-query-min))
            (builds-id-max (and=> query db-get-builds-query-max))
            (border-low-id (assq-ref params 'border-low-id))
            (border-high-id (assq-ref params 'border-high-id)))
       (if query
           (respond-html
            (html-page
             "Search results"
             (build-search-results-table
              query
              (handle-builds-search-request
               `((query . ,query)
                 (nr . ,%page-size)
                 (order . finish-time+build-id)
                 (border-low-id . ,border-low-id)
                 (border-high-id . ,border-high-id)))
              builds-id-min
              builds-id-max)
             '()))
           (respond-json-with-error 500 "Query parameter not provided!"))))

    (("static" path ...)
     (respond-static-file path))
    ('method-not-allowed
     ;; 405 "Method Not Allowed"
     (values (build-response #:code 405) #f #f))
    (_
     (respond-not-found (uri->string (request-uri request))))))

(define* (run-cuirass-server #:key (host "localhost") (port 8080))
  (let* ((host-info  (gethostbyname host))
         (address    (inet-ntop (hostent:addrtype host-info)
                                (car (hostent:addr-list host-info)))))
    (log-message "listening on ~A:~A" address port)

    ;; Here we use our own web backend, call 'fiberized'.  We cannot use the
    ;; 'fibers' backend that comes with Fibers 1.0.0 because it does its own
    ;; thread creations and calls 'run-fibers' by itself, which isn't
    ;; necessary here (and harmful).
    ;;
    ;; In addition, we roll our own instead of using Guile's 'run-server' and
    ;; 'serve-one-client'.  The key thing here is that we spawn a fiber to
    ;; process each client request and then directly go back waiting for the
    ;; next client (conversely, Guile's 'run-server' loop processes clients
    ;; one after another, sequentially.)  We can do that because we don't
    ;; maintain any state across connections.
    ;;
    ;; XXX: We don't do 'call-with-sigint' like 'run-server' does.
    (let* ((impl (lookup-server-impl 'fiberized))
           (server (open-server impl `(#:host ,address #:port ,port))))
      (let loop ()
        (let-values (((client request body)
                      (read-client impl server)))
          ;; Spawn a fiber to handle REQUEST and reply to CLIENT.
          (spawn-fiber
           (lambda ()
             (let-values (((response body state)
                           (handle-request url-handler request body '())))
               (write-client impl server client response body)))))
        (loop)))))