use re
use str

var cmd      = $e:qpdf~

fn -is-pdf {|f|
  str:has-suffix $f .pdf
}

fn -is-number {|arg|
  re:match '^\d+$' $arg
}

fn -is-rotate {|arg|
  re:match '^(\+|-)(\d+):.*' $arg
}

fn -is-seq {|arg|
  re:match '^\d+(,\d+)*$' $arg
}

fn -must-pdf {|f|
  if (not (-is-pdf $f)) {
    fail $f' n’est pas un fichier PDF'
  }
}

fn -must-not-exist {|f|
  var exist = ?(stat $f 2>&- > /dev/null)
  if (bool $exist) {
    fail $f' existe déjà'
  }
}

fn -must-exist {|f|
  var exist = ?(stat $f 2>&- > /dev/null)
  if (not (bool $exist)) {
    fail $f' n’existe pas'
  }
}

fn -make-tmp {
  mktemp -q /tmp/qpdf_XXXXXXXXXX.pdf
}

fn -make-seq {|seq|
  if (not (-is-seq $seq)) {
    fail $seq': pas une séquence'
  }
  set @seq = (order (str:split , $seq))
  var b = 1
  each {|ei|
    var e = (- $ei 1)
    if (== $b $e) {
      put $b
      set b = $ei
    } elif (< $b $e) {
      put $b'-'$e
      set b = $ei
    }
  } $seq
  put $b'-z'
}

fn -out {|in suffix|
  var out = (str:trim-suffix $in .pdf)
  str:join '' [ $out .pdf ]
}

fn -parse-selection {|in selection|
  if (-is-rotate $selection) {
    var out   = (-make-tmp)
    var i     = (str:index $selection :)
    var r sel = $selection[..$i] $selection[(+ $i 1)..]
    if (eq sel '') {
      set @sel = $in
    } else {
      set @sel = $in $sel
    }
    $cmd --empty --pages $@sel -- $out
    $cmd $out --replace-input --rotate=$r
    put $out
  } else {
    put $in $selection
  }
}

fn -parse-all {|args|
  var tmpfiles  = []
  var selection = []
  var in        = $nil
  var miss      = $nil
  try {
    each {|e|
      if (-is-pdf $e) {
        -must-exist $e
        if (not-eq $miss $nil) {
          set @selection = $@selection $miss
          set miss = $e
        }
        set in = $e
      } else {
        if (eq $in $nil) {
          fail 'Le pagerange doit être déclaré après un fichier d’entrée'
        }
        var @s = (-parse-selection $in $e)
        if (== (count $s) 1) {
          set @tmpfiles = $@tmpfiles $@s
        }
        set @selection = $@selection $@s
      }
    } $args
  } finally {
    put $selection $tmpfiles
  }
}

fn -merge {|&collate=$nil selection out|
  if (< (count $selection) 1) {
    fail 'Aucune sélection'
  }
  var @args = --empty --pages $@selection -- $out
  if (not-eq $collate $nil) {
    if (-is-number $collate) {
      set @args = $collate $@args
    }
    set @args = --collate $@args
  }
  $cmd $@args
}

fn merge {|@args|
  var l = (- (count $args) 1)
  if (< $l 1) {
    fail "la commande doit contenir au moins 2 paramètres"
  }
  var out = $args[$l]
  -must-pdf $out
  -must-not-exist $out

  var sel tmp = [] []
  try {
    set sel tmp = (-parse-all $args[..$l])
    -merge $sel $out
  } finally {
    if (> (count $tmp) 0) {
      rm -f $@tmp
    }
  }
}

fn split {|@args|
  var l = (- (count $args) 1)
  if (< $l 1) {
    fail "la commande doit contenir au moins 2 paramètres"
  }
  var out = $args[$l]
  -must-pdf $out
  -must-not-exist $out
  set args = $args[..$l]

  var size = $nil
  if (-is-number $args[0]) {
    set size @args = @args
  }

  var sel tmp = [] []
  try {
    set sel tmp = (-parse-all $args[..$l])
    var t = (-make-tmp)
    -merge $sel $t
    set @tmp = $@tmp $t
    var @ac = --split-pages
    if (not-eq $size $nil) {
      set @ac = $@ac $size
    }
    set @ac = $@ac $t $out/%d.pdf
    mkdir $out
    $cmd $@ac
  } finally {
    if (> (count $tmp) 0) {
      rm -f $@tmp
    }
  }
}

fn split-at {|@args|
  var l = (- (count $args) 1)
  if (< $l 2) {
    fail "la commande doit contenir au moins 3 paramètres"
  }
  var out = $args[$l]
  -must-pdf $out
  -must-not-exist $out
  var @seq = (-make-seq $args[0])
  set args = $args[1..$l]

  var sel tmp = [] []
  try {
    set sel tmp = (-parse-all $args[..$l])
    var t = (-make-tmp)
    -merge $sel $t
    set @tmp = $@tmp $t
    var i = 1
    each {|s|
      $cmd --empty --pages $t $s -- $out/$i.pdf
      set i = (+ $i 1)
    } $seq
  } finally {
    if (> (count $tmp) 0) {
      rm -f $@tmp
    }
  }
}

fn zip {|@args|
  var l = (- (count $args) 1)
  if (< $l 1) {
    fail "la commande doit contenir au moins 2 paramètres"
  }
  var out = $args[$l]
  var col = $true
  -must-pdf $out
  -must-not-exist $out
  set args = $args[..$l]

  if (-is-number $args[0]) {
    set col @args = $@args
  }

  var sel tmp = [] []
  try {
    set sel tmp = (-parse-all $args)
    -merge &collate=$col $sel $out
  } finally {
    if (> (count $tmp) 0) {
      rm -f $@tmp
    }
  }
}

fn unzip {|@args|
  echo '<en construction…>'
}

fn decrypt {|@args|
  var l = (count $args)
  if (or (< $l 1) (> $l 3)) {
    fail "decrypt doit contenir entre 1 et 3 paramètres"
  }
  var in  = $args[0]
  -must-pdf $in
  -must-exist $in
  var out = (-out $in _decrypted.pdf)
  var p   = $nil
  if (> $l 1) {
    set p = $args[1]
    if (== $l 3) {
      set out = $args[2]
      -must-pdf $out
    }
  }
  -must-not-exist $out
  if (eq $p $nil) {
    $cmd $in $out --decrypt
  } else {
    $cmd $in $out --decrypt $p
  }
}

fn help {|@args|
  cat $E:HOME/.config/elvish/aliases/qpdf.help
}

fn info {|@args|
  echo '<en construction…>'
}

edit:add-var epdf~ {|action @args|
  var actions = [
    &merge=$merge~
    &split=$split~
    &split-at=$split-at~
    &zip=$zip~
    &unzip=$unzip~
    &decrypt=$decrypt~
    &help=$help~
    &info=$info~
  ]
  if (not (has-key $actions $action)) {
    fail $action': action inconnue'
  }
  $actions[$action] $@args
}