;;; Handle the Search Path for XCVB modules.
#+xcvb (module (:depends-on ("commands" "grain-registry")))
(in-package :xcvb)

;;; The Source Registry itself.
;;; We directly use the code from ASDF, therefore ensuring 100% compatibility.

(defparameter *flattened-source-registry* ()
  "Either NIL (for uninitialized), or a list of one element,
said element itself being a list of directory pathnames where to look for build.xcvb files")

(defparameter *source-registry-searched-p* nil
  "Has the source registry been searched yet?")

(defparameter *builds*
  (make-hash-table :test 'equal)
  "A registry of known builds, indexed by canonical name.
Initially populated with all build.xcvb files from the search path.")

(defparameter *truename-build-fullnames*
  (make-hash-table :test 'equal)
  "A registry of known build fullnames, indexed by truename.
Initially populated with all build.xcvb files from the search path.")

;;; Special magic for build entries in the registry

(defmethod brc-pathnames ((build build-module-grain))
  (list (grain-pathname build)))
(defmethod brc-pathnames ((build invalid-build-file))
  (list (grain-pathname build)))

(defun make-invalid-ancestor-build-file (&key fullname pathname ancestor root)
  (make-instance 'invalid-build-file
    :root root
    :fullname fullname
    :pathname pathname
    :reason (format nil "ancestor ~A at ~A is invalid because of~%~A~&"
                    (fullname ancestor)
                    pathname
                    (invalid-build-reason ancestor))))

(defmethod invalid-build-reason ((x build-registry-entry))
  (format nil "a conflict between same-named builds at~%~{~S~&~}"
          (brc-pathnames x)))

(defun pathname-build (pathname)
  (loop :with truename = (truename pathname)
    :for build :being :the :hash-values :of *builds* :do
    (flet ((same-truename-p (pathname)
             (equal (truename pathname) truename)))
      (etypecase build
        (build-module-grain
         (when (same-truename-p (grain-pathname build))
           (return build)))
        (require-grain
         nil)
        (build-registry-conflict
         (when (find-if #'same-truename-p (brc-pathnames build))
           (error 'build-conflict
                  :fullname (fullname build)
                  :pathname pathname
                  :conflicts (remove-if #'same-truename-p (brc-pathnames build)))))))))

(defun compute-xcvb-source-registry (&optional parameter)
  (let ((*default-pathname-defaults* (or *xcvb-lisp-directory* *default-pathname-defaults*)))
    ;; Check to see that if this envar is defined to a non-empty string
    ;; ensure that it is an absolute path to, not a relative one.
    (handler-case
        (asdf::flatten-source-registry parameter)
      (error (c)
        (user-error "Could not properly parse the source registry:~%~A" c)))))

(defparameter *sbcl-contribs*
  '(;;:asdf-install
    :sb-aclrepl
    :sb-bsd-sockets
    :sb-cltl2
    :sb-concurrency
    :sb-cover
    ;;:sb-daemon
    :sb-executable
    :sb-grovel
    :sb-introspect
    :sb-md5
    :sb-posix
    :sb-queue
    :sb-rotate-byte
    :sb-rt
    :sb-simple-streams
    :sb-sprof)
  "special systems that are part of SBCL")

(defun initialize-builds ()
  (log-format 10 "Initializing builds to supersede ASDF...~%")
  (clrhash *builds*)
  (when (eq *lisp-implementation-type* :sbcl)
    (loop :for x :in *sbcl-contribs*
       :for n = (string-downcase x) :do
       (log-format 10 "  Initializing specific build to supersede ASDF: ~S~%"
		   n)
       (setf (registered-build `(:supersedes-asdf ,n)) (make-require-grain :name n)))))

(defun initialize-xcvb-source-registry (&optional (parameter asdf:*source-registry-parameter*))
  (setf asdf:*source-registry-parameter* parameter)
  (initialize-builds)
  (log-format 10  "Initializing source registry: ")
  (let ((source-registry (compute-xcvb-source-registry parameter)))
    (setf *flattened-source-registry* (list source-registry))
    (log-format-pp 10 "~S~%" *flattened-source-registry*))
  (search-source-registry parameter))

(defun assert-source-registry ()
  (unless *flattened-source-registry*
    (error "You should have already initialized the source registry by now!")))

;;; Now for actually searching the source registry!

(defun finalize-source-registry ()
  (log-format 10 "Finalizing (verifying) source registry~%")
  (setf *flattened-source-registry*
        (list
         (while-collecting (c)
           (loop :with visited = (make-hash-table :test 'equal)
             :for (path . flags) :in (car *flattened-source-registry*)
             :for tn = (probe-file* path)
             :for ns = (and tn (namestring tn)) :do
             (cond
               ((not tn)
                (log-format 7 "  Discarding invalid path element ~S" path))
               ((gethash ns visited)
                (log-format 7 "  Discarding duplicate path element ~S" path))
               (t
                (log-format 8 "  Verified path element: ~S ~S" path flags)
                (setf (gethash ns visited) t)
                (c (cons tn flags)))))))))

(defvar +build-path+
  (make-pathname :directory nil
                 :name "build"
                 :type "xcvb"
                 :version :newest))

(defun pathname-newest-version-p (x)
  (or
   (member (pathname-version x) '(nil :newest :unspecific))
   (and (integerp (pathname-version x))
        (equal (truename x) (truename (make-pathname :version :newest :defaults x))))))

(defun pathname-is-build.xcvb-p (x)
  (and (equal (pathname-name x) "build")
       (equal (pathname-type x) "xcvb")
       #+genera (pathname-newest-version-p x)))

(defun build.xcvb-in-directory (directory)
  (merge-pathnames* +build-path+ directory))

(defun directory-has-build-file-p (directory)
  (ignore-errors
    (and (asdf::directory* (build.xcvb-in-directory directory)) t)))

(defun collect-sub*directories-with-build.xcvb
    (directory &key
     (exclude *default-source-registry-exclusions*)
     collect)
  (asdf::collect-sub*directories
   directory
   #'directory-has-build-file-p
   #'(lambda (x) (not (member (car (last (pathname-directory x))) exclude :test #'equal)))
   collect))

(defun find-build-files-under (root)
  (destructuring-bind (pathname &key recurse (exclude asdf::*default-source-registry-exclusions*))
      root
    (if (not recurse)
        (let ((path (probe-file (merge-pathnames* +build-path+ pathname))))
          (when path (list path)))
	(mapcar 'build.xcvb-in-directory
		(while-collecting (c)
		  (collect-sub*directories-with-build.xcvb
		   pathname :exclude exclude :collect #'c))))))

(defun map-build-files-under (root fn)
  "Call FN for all BUILD files under ROOT"
  (log-format-pp
   10 "Processing all build.xcvb files in source registry root:~%    ~S~%"
   root)

  (let* ((builds (find-build-files-under root))
         ;; depth first traversal
         (builds (sort (mapcar #'truename builds) #'<
                       :key (compose #'length #'pathname-directory))))
    (map () fn builds)))

(defun search-source-registry (&optional (parameter asdf:*source-registry-parameter*))
  (log-format 10 "Searching for build files in source registry")
  (finalize-source-registry)
  (dolist (root (car *flattened-source-registry*))
    (log-format 10 " Searching for build files under ~S" root)
    (map-build-files-under root #'(lambda (x) (register-build-file x root)))
    (confirm-builds-under root))
  (search-source-registry-asdf parameter)) ;; TODO: handle packages from Quicklisp?

(defun search-source-registry-asdf (&optional (parameter asdf:*source-registry-parameter*))
  (asdf:initialize-source-registry parameter)
  (loop :for name :being :the :hash-keys :of asdf::*source-registry*
    :for fullname = `(:asdf ,name) :do
    (register-build-named fullname (make-instance 'asdf-grain :name name) :asdf))
  (unless (gethash "asdf" asdf::*source-registry*)
    (setf (registered-build `(:supersedes-asdf "asdf")) (make-require-grain :name "asdf"))))


(defun ensure-source-registry-searched ()
  (unless *source-registry-searched-p*
    (search-source-registry)))

;;;; Registering a build

(defun supersedes-asdf-name (x)
  (let ((name (etypecase x
                (string x)
                (cons (car x)))))
    `(:supersedes-asdf ,(coerce-asdf-system-name name))))

(defun registered-build (name &key ensure-build)
  (let ((build (gethash name *builds*)))
    (when ensure-build
      (unless (build-module-grain-p build)
        (error "Could not find a build with requested fullname ~A. Try xcvb show-source-registry"
               name)))
    build))

(defun (setf registered-build) (build name &key ensure-build)
  (when ensure-build
    (unless (build-module-grain-p build)
      (error "Cannot register build ~S to non-build grain ~S" name build)))
  (setf (gethash name *builds*) build))

(defun fullname-from-truename (truename)
  (gethash truename *truename-build-fullnames*))

(defun (setf fullname-from-truename) (fullname truename)
  (setf (gethash truename *truename-build-fullnames*) fullname))

(defun register-build-file (build root)
  "Registers build file build.xcvb (given as truename)
as having found under root path ROOT (as pathname),
for each of its registered names."
  (log-format 10 "  Registering build file ~S in ~S" build root)
  (let* ((build-module-grain
          (make-grain-from-file build :build-p t))
         (fullname (when build-module-grain (fullname build-module-grain))))
    (flet ((register-entry (entry)
             (setf (gethash build *truename-build-fullnames*) (fullname entry))
             (register-build-named fullname entry root)))
      (cond
        ((null fullname)
         (log-format 5 "Failed to parse build file at ~S" build))
        ((slot-boundp build-module-grain 'root)
         (log-format 7 "Already visited build at ~S" build))
        ((typep (grain-parent build-module-grain) 'invalid-build-registry-entry)
         (register-entry
          (make-invalid-ancestor-build-file
           :fullname fullname :pathname build :root root
           :ancestor (grain-parent build-module-grain))))
        (t
         (setf (bre-root build-module-grain) root)
         (register-entry build-module-grain))))
    (values)))

(defun confirm-builds-under (root)
  (log-format 10 "Confirming build files discovered under ~S" root)
  ;; This will try to register the secondary names of otherwise valid builds.
  (loop
    :with builds-under-root = (loop :for b :being :the :hash-values :of *builds*
                                :when (and (build-module-grain-p b) (equal (bre-root b) root))
                                :collect b)
    ;; Making sure we confirm parents before children, based on fullname length.
    :for b :in (sort builds-under-root #'< :key (compose #'length #'fullname))
    :for p = (grain-parent b) :do
    (if (or (null p) (eq p (registered-build (fullname p))))
        ;; The parent has already been visited and has not been invalidated,
        ;; so the current build is valid, and we register its secondary names.
        (dolist (name (append (mapcar #'canonicalize-fullname (nicknames b))
                              (mapcar #'supersedes-asdf-name (supersedes-asdf b))))
          (register-build-named name b root))
        (let* ((fullname (fullname b))
               (invalid
                (make-invalid-ancestor-build-file
                 :fullname fullname :pathname (grain-pathname b) :ancestor p :root root)))
          (setf (registered-build fullname) invalid)))))

(defun merge-build (previous-build new-build name root)
   ;; Detect ambiguities.
  ;; If the name has already been registered, then
  ;; * if the previous entry is from a previous root, it has precedence
  ;; * else if the previous entry is from same root and is in an ancestor directory,
  ;;   it has precedence
  ;; * otherwise, it's a conflict, and the name shall be marked as conflicted and
  ;;   an error be printed if/when it is used.
  ;; Note: to do that in a more functional way, have some mechanism
  ;; that applies a modify-function to a gethash value, allowing (values NIL NIL) to specify remhash.
  (check-type previous-build (or null invalid-build-registry-entry build-module-grain))
  (cond
    ((null previous-build)
     ;; we're the first entry with that name. Bingo!
     new-build)
    ((equal (bre-root previous-build) root)
     ;; There was a previous entry in same root:
     ;; there's an ambiguity, so that's a conflict!
     (make-instance 'build-registry-conflict
                    :fullname name
                    :pathnames (cons (grain-pathname new-build) (brc-pathnames previous-build))
                    :root root))
    (t
     ;; There was a previous entry in a previous root,
     ;; the previous entry takes precedence -- do nothing.
     previous-build)))

(defun register-build-named (name build-module-grain root)
  "Register under NAME pathname BUILD found in user-specified ROOT."
  (funcallf (registered-build name) #'merge-build build-module-grain name root))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Show Search Path ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defgeneric build-string-description (entry fullname)
  (:documentation "A human readable description of this grain"))

(defmethod build-string-description ((entry asdf-grain) fullname)
  (assert (and (list-of-length-p 2 fullname) (eq (first fullname) :asdf)))
  (let ((name (second fullname)))
    (format nil "(:asdf ~S :directory ~S)" name
            (pathname-directory-pathname
             (nth-value 2 (asdf:locate-system name))))))

(defmethod build-string-description ((entry require-grain) fullname)
  (assert (and (list-of-length-p 2 fullname) (eq (first fullname) :supersedes-asdf)))
  (format nil "(:asdf ~S :superseded-by ~S)"
	  (second fullname) (fullname entry)))

(defmethod build-string-description ((entry build-module-grain) fullname)
  (if (and (list-of-length-p 2 fullname) (eq (first fullname) :supersedes-asdf))
      (let* ((nn (second (assoc (second fullname)
				(asdf-supersessions (finalize-grain entry))
				:test 'equal)))
	     (b (registered-build nn)))
	(format nil "(:asdf ~S :superseded-by ~S)"
		(second fullname) (if b `(:BUILD ,nn) `(:FASL ,nn))))
      (format nil "(:build ~S :in-file ~S)"
	      fullname (namestring (grain-pathname entry)))))

(defmethod build-string-description ((entry invalid-build-file) fullname)
  (format nil "(:invalid-build :with-fullname ~S :in-file ~S)"
	  fullname (grain-pathname entry)))

(defmethod build-string-description ((entry build-registry-conflict) fullname)
  (format nil "(:invalid-build :registry-conflict ~S :among ~S)"
	  fullname (mapcar 'namestring (brc-pathnames entry))))

(defun show-source-registry ()
  "Show registered builds"
  (let ((*print-case* :downcase))
    (format t "~&;; Registered search paths:~%(:search-paths ~{~% ~S~})~%~%"
	    (car *flattened-source-registry*))
    (format t ";; Builds found in the search paths:~%(:builds ")
    (flet ((entry-string (x)
	     (destructuring-bind (fullname . entry) x
	       (build-string-description entry fullname))))
      (format t "~{~% ~A~})~%"
	      (sort (mapcar #'entry-string
			    (hash-table->alist *builds*)) #'string<)))))

(define-command show-source-registry-command
    (("show-source-registry" "source-registry" "ssr")
     (&rest keys &key)
     `(,@+source-registry-option-spec+
       ,@+verbosity-option-spec+)
     "Show builds in the configured source registry"
     "Show builds in the implicitly or explicitly configured source registry.
For debugging your XCVB configuration."
     ignore)
  (apply 'handle-global-options :use-target-lisp nil keys)
  (show-source-registry))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Find Module ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(define-command find-module
    (("find-module" "fm")
     (&rest keys &key)
     `((("name" #\n) :type string :optional nil :list t :documentation "name to search for")
       (("short" #\s) :type boolean :optional t :documentation "short output")
       ,@+source-registry-option-spec+
       ,@+verbosity-option-spec+)
     "Show builds in the specified XCVB path"
     "Show builds in the implicitly or explicitly specified XCVB path.
For debugging your XCVB configuration."
     (name short))
  (apply 'handle-global-options :use-target-lisp nil keys)
  (let ((all-good t))
    (dolist (fullname name)
      (let ((grain (resolve-absolute-module-name fullname)))
        (cond
          (grain
           (if short
             (format t "~A~%" (namestring (grain-pathname grain)))
             (format t "Found ~S at ~S~%" (fullname grain) (namestring (grain-pathname grain)))))
          (t
           (format *error-output* "Could not find ~S. Check your paths with xcvb ssr.~%" fullname)
           (setf all-good nil)))))
    (exit (if all-good 0 1))))