#! /usr/bin/env bash

## This bash script checks that example code in markdown files runs as expected.
##  -- the script expects to be located in dafny/docs
##      and finds other parts of the dafny working tree
##      relative to that location
##  -- it is intended to be run within a development or CI environment. That is, it finds 
##     an executable dafny presuming such an environment. (The variable $dafny in the
##     script says what executable to use.)
##  -- There is only one command-line option, '-c', which
##     if present must be first. It sets the coverage mode
##     described below.
##
## What is checked?
## In each input file in turn, each code block delineated by
## markdown ``` pairs is checked, as described below.
## -- Each block is expected to have a language tag. Often this
##    tag is "dafny" (as in ```dafny) but may be other tags as well.
##    A reasonable tag to disable checking is "text".
##    If there is no tag a default tag is used (see below).
##    The script warns if there is no tag and no default.
## -- No whitespace is permitted between ``` and the tag.
## -- Markdown itself does not allow any other text on this delimiter line.
## -- The script is not robust against mismatched ``` pairs.
##
## Operational modes -- there are three modes of operation.
##    -- checking the code against an expected output file (the default behavior)
##    -- checking the code for a given error message (if %useHeadings has been set)
##    -- producing lit files for coverage checking (if the -c command-line option is present)
##
## What command is used to check?
## Instructions for checking each code block are given in a single-line HTML
## comment (which is also a markdown comment), namely, keywords
## enclosed in <!-- and -->, with the first character of the enclosed text being a '%'. 
## The text inside any such comment is interpreted as potential command information. 
##
## Global defaults.
## If the command information line contains '%default', then the 
## contents of the line are used to set defaults that apply for the
## remainder of the file (until a subsequent default setting command).
## Possible settings are:
## - if '%useHeadings' is present then the checks are against error messages, as described below
## - if '%check-ids' is present, the error-ids are checked as described below
## - if '%lang=' is present, then the alpha-numeric word after the = sign is now the default language
## - if '%exit=n' is present, then the default exit code is the value of n
## - if '%options' is present, then everything that follows is the default string of command options
## - the first word of a default line is taken as the default command, if that word is not %default
##   e.g. <!-- %check-resolve %default --> sets the default command to %check-resolve
##
## Each code block is checked according to command information set just before the code block.
## If there is no such line, the defaults above are used. The information just before a code block
## applies only to that code block.
## For example:
##   <!-- %check-resolve -->
##   ```dafny
##     ... code...
##   ```
## The command information has the format <!-- command [ expected-output ] [ other options ]  -->
## - The command has one of the forms
##    %no-check  -- meaning to skip any checking of this block
##    %check-cli -- meaning to execute the code as bash shell commands. The language must be 'bash'
##    %check-legacy -- meaning to check with dafny's legacy cli
##    %check-verb -- where 'verb' is one of dafny's new-cli verbs (e.g. resolve or verify or test)
##    The %check-verb form can have '-warn' appended to indicate that only warnings, not errors are expected
## - If the expected-output is present it is a file name (of a file in the same folder as the markdown file 
##    being tested). If the name is present, then the output of the command is checked against the content of the file
##    (and is expected to match exactly).
## - The 'other options' can be any one of these:
##    %save <file> -- save the code block (including anything appended from %use) in the given temporary file
##    %use <file> -- append to the code block the content of the given file (often a temporary saved by a previous %save)
##    %nomsg -- forget the error pattern from the heading (in the case of subsequent working examples in the explanation)
##    %first -- only look at the first error message produced (usually because the error recovery is poor)
##    %err -- check stderr output instead of stdout
##    %exit <n> -- set the expected exit code of the command.
##       If not set, the default set in the %default command is used.
##       If that is not set,  The default exit code is
##          -- 0 if there is no output file and %iuseHeadings is not being used
##          -- 0 if the command includes 'warn'
##          -- if there is an output file and no 'warn', then the default exit code depends on the verb
##    %options ... -- must be last; everything that follows is the list of options to use. If not present, then the default
##          option list is used. If that is not present a built-in default is used.
##
## Mode: Compare against output file
##   In this mode, the command is assembled as stated above and run against the code block.
##   Note that the code block (together with anything included via %use) must be a full dafny
##   program. There is no support for testing just simple expressions.
##   The exit code is compared against the expected exit code.
##   The actual output is compared aginst the stated output file, if any, and otherwise ignored.
##
## Mode: Compare against error message
##   This mode is for the special case of checking the error catalog (the HowToFAQ/Errors-*.md files).
##   These files consist of sections, each of which has a heading stating an error message and errorid,
##   a ```-delineated code snippet that is an example of the error message, and then more explanation of the error.
##   The heading line (which starts with '## **Error:' or '## **Warning:') is parsed to
##   determine the errorid and a regular expression that matches the expected error messages.
##   The test consists of running the command against the code snippet, extracting the error message and errorid
##   from the output and checking those against the expected values.
##
##   The error message as given in the header has italicized words (markdown: _word_) for variable text in the error 
##   message. The script turns these headings into regular expressions, taking into account the presence of 
##   characters special to regex processing.
##
## Mode: Generate lit
##   The -c option to the script causes lit files to be generated and written to Test/docexamples (see $outdir in the script below)
##   If these files are generated during CI prior to running integration tests, then they are both executed
##   as part of the integration tests and included in the coverage metrics. Importantly, all the error
##   catalog tests are then part of the coverage metrics.
##
##   In this mode, the code is not checked, just the lit files generated.
##
##   Also, currently, the generated lit commands just run dafny against the given dafny code and check the exit code.
##   They do not check the results other than the exit code.
##   Perhaps someday the full test will be made into a lit test and we won't need this script to do the testing.


dir=$(dirname "${BASH_SOURCE[0]}")
dir=`cd "$dir" && pwd`
dafnydir=$dir/../Scripts
dafny="$dafnydir/dafny"
outdir="$dir/../Test/docexamples"

coverage=0
permOptions="--show-snippets:false "
defOptions="--function-syntax:4 --use-basename-for-filename"
legacyOptions="-functionSyntax:4 -useBaseNameForFileName -showSnippets:0"

while getopts 'c' opt; do
  case "$opt" in
    "c") coverage=1; rm -rf $outdir; mkdir -p $outdir ;;
  esac
done
shift $(($OPTIND - 1))

## Tracks if there have been any failures
ANYFAIL=0

## Loop over all remaining command-line arguments
for file in $@ ; do
dir=$(dirname "$file")
dir=`cd "$dir" && pwd`

defaultCommand=
defaultExit=
defaultLang=
useHeadings=0
checkIds=0

## Temporary files
text="$dir/text.dfy"
actualOut="$dir/actual_out.tmp"
actualMsgs="$dir/actual_msgs.tmp"
actualError="$dir/actual_error.tmp"
tocheck="$actualOut"

## Whether this file fails
FAIL=0
## line number
n=0
## if inblock==1 we are in a ```-delimited block
inblock=0

msg=
use=
expectedExit=
command=
expectFile=
options=( )
first=0
checkerr=0
default=0
globalDefaultExit=
## Read and process each line of the file.  The file is input on stdin 
## by redirection after the 'done' corresponding to this while-do
while IFS= read -r line
do 
  let n++

  ## For header lines, extract the error message from the header text
  ## (everything but the initial ##[ ]*, the enclosing ** and the appended {#_errorid_})
  ## The sed commands turn this into a pattern matching regex to match against the output of applying dafny to the example in the text:
  ## remove the trailing error id if present; remove initial ## **; remove trailing '**' and errorid; turn any italicized text, which marks some
  ## hole in the template to a '.*' matcher. Also, escape any regex-special characters.

  ( echo "$line" | grep -E -e '[#][#] ' > /dev/null ) \
   && msg=`echo "$line" | sed -E -e 's/ [ ]*\{#.*\}[ ]*$//' -e 's/^##[ ]*[*]*//' -e 's/[*]*$//' -e 's/\\*/\\\\*/' -e 's/\[/\\\[/g' -e 's/\]/\\\]/g' -e 's/_[A-Za-z]+_/.*/g'`\
   && expid=`echo $line | sed -e 's/^.*[\{][\#]//' -e 's/[\}]$//'`
  if [ "$checkIds" == "0" ]; then expid= ; fi
  ## msg - the error message turned into a regex
  ## expid -- the expected errorId if any

  ## Check for the test command information
  echo "$line" | grep '^[ ]*<!-- [ ]*%' > /dev/null
  if [ "$?" == "0" ]; then 
      ##echo COMMAND "$line"
      contents=( `echo "$line" | sed -e 's/[^<]*<!--//' -e 's/-->//'` )
      echo "$line" | grep -e '%default' > /dev/null
      if [ "$?" == "0" ]; then 
        default=1; 
        echo "$line" | grep -e '%useHeadings' > /dev/null
        if [ "$?" == "0" ]; then useHeadings=1; fi
        echo "$line" | grep -e '%lang=' > /dev/null
        if [ "$?" == "0" ]; then defaultLang=`echo "$line" | sed -e 's/^.*%lang=//' | sed -e 's/ .*$//'` ; fi
        echo "$line" | grep -e '%exit=' > /dev/null
        if [ "$?" == "0" ]; then globalDefaultExit=`echo "$line" | sed -e 's/^.*%exit=//' | sed -e 's/ .*$//'` ; fi
        echo "$line" | grep -e '%check-ids' > /dev/null
        if [ "$?" == "0" ]; then checkIds=1; fi
        defaultCommand=${contents[0]}
        continue
      fi
      command=${contents[0]}
      contents=( ${contents[@]:1} )
      while [ ${#contents[@]} != "0" ]; do
        if [ "${contents[0]}" == "%use" ]; then
          use=${contents[1]}
          contents=( ${contents[@]:2} )
        elif [ "${contents[0]}" == "%save" ]; then
          save=${contents[1]}
          contents=( ${contents[@]:2} )
        elif [ "${contents[0]}" == "%exit" ]; then
          expectedExit=${contents[1]}
          contents=( ${contents[@]:2} )
        elif [ "${contents[0]}" == "%err" ]; then
          tocheck="$actualError"
          contents=( ${contents[@]:1} )
        elif [ "${contents[0]}" == "%first" ]; then
          first=1
          contents=( ${contents[@]:1} )
        elif [ "${contents[0]}" == "%nomsg" ]; then
          msg=
          contents=( ${contents[@]:1} )
        elif [ "${contents[0]}" == "%options" ]; then
          contents=${contents[@]:1}
          options=${contents[@]}
          contents=()
        elif [ -z "${contents[0]}" ]; then
          contents=()
        else
          expect=${contents[0]}
          contents=( ${contents[@]:1} )
        fi
      done
  fi
  ## Check for the marker
  echo "$line" | grep -e '^[ ]*[`][`][`]' > /dev/null 
  if [ "$?" != "0" ]; then
    if [ "$inblock" == "1" ]; then
      ## If in a backtick block, save the text to the temporary file - erase any ... which are just placeholders in some examples
      echo "$line" | sed -e 's/^[ ]*\.\.\./   /' >> $text
    fi
  elif [ "$inblock" == "0" ]; then
    ## Start of backtick block
    ## get language
    lang=`echo "$line" | sed -e 's/^[ ]*\`\`\`[\`]*//' -e 's/[ ]*$//'`
    if [ -z "$lang" ]; then
      lang=$defaultLang
      if [ -z "$lang" ]; then
        echo NO LANGUAGE LABEL $n "$line"
        FAIL=1
      fi
    fi

    inblock=1
    rm -f "$text"
    touch "$text"
  else
      ## End of backtick block, so check the text
      if [ -z "$command" -a "$lang" == "dafny" ]; then
        command="$defaultCommand"
        if [ -z "$command" ]; then
          echo "NO COMMAND GIVEN $n $line"
          FAIL=1
        fi
      fi
      inblock=0
      if [ -n "$use" ]; then
        cat "$use" >> $text
      fi
      if [ -n "$save" ]; then
         cp $text $save
         save=
      fi
      if [ "$lang" == "dafny" -o "$lang" == "cli" -o "$lang" == "bash" ]; then
        ## This script can take some time, so this reports progress
        if [ "$coverage" == "1" ]; then
          echo "GENERATING $n $file $command $expect $expid"
        else
          echo "TESTING $n $file $command $expect $expid"
        fi
      fi
      ischeck=0
      echo $command | grep '%check-' >> /dev/null
      if [ "$?" == "0" ]; then ischeck=1; fi
      iswarn=0
      echo $command | grep 'warn' >> /dev/null
      if [ "$?" == "0" ]; then iswarn=1; fi
      verb=`echo $command | sed -e 's/%check-//' -e 's/-warn//'`
      if [ "$command" == "%no-check" ]; then
        echo -n ""
      elif [ "$verb" == "cli" ]; then
        ## These are command-line error tests, so the expected exit is typically 1
        if [ -z "$expectedExit" ]; then expectedExit=1 ; fi
        if [ "$lang" != "bash" ]; then
          echo EXPECTED A bash BLOCK, NOT $lang
          FAIL=1
        elif [ "$coverage" == "1" ]; then
          ## The lit tests currently expect the text of the test to start with 'dafny' and become '%baredafny'
          
	  f="$outdir/$(basename $file)_${n}.dfy"
          echo "// RUN: %exits-with" $expectedExit "%bare`cat $text`" " > /dev/null 2> /dev/null" > "$f"
        else
          isverbose=
          if [ "$checkIds" == "1" ]; then isverbose="--verbose" ; fi
          PATH="$dafnydir:$PATH" . $text $isverbose > "$actualOut" 2> "$actualError"
          actualExit=$?
          if [ "$actualExit" != "$expectedExit" ]; then
             if [ "$actualExit" == "127" -a "$expectedExit" == "1" ]; then
               echo EXIT CODE is $actualExit
               which dafny
             else
               echo EXPECTED EXIT CODE OF $expectedExit, GOT $actualExit
               FAIL=1
             fi
          fi
          if [ "$first" == "1" ]; then
            act=`cat "$tocheck" | head -1 | sed -e 's/^.*Error/Error/'`
          else
            act=`cat "$tocheck" | sed -e 's/^.*Error/Error/'`
          fi
          dif=`echo "$act" | tr "\n" " " | sed -e 's/[ ]*$//' -e "s@$msg@@"`
          if [ -n "$dif" ]; then
            echo ACTUAL OUTPUT DOES NOT MATCH EXPECTED: "$msg" VS "$act"
            FAIL=1
          elif [ -z "$act" -a "$useHeadings" == "1" ]; then
            echo "NO OUTPUT TO COMPARE"
            FAIL=1
          fi
        fi
      elif [ "$ischeck" == "1" ]; then ## Not cli though
        dOptions=$defOptions
        if [ -z "$expect" -a "$useHeadings" == "0" ]; then
          defaultExit=0
        elif [ "$iswarn" == "1" ]; then
          dOptions="$dOptions --allow-warnings"
          defaultExit=0
        elif [ "$verb" == "verify" ]; then
          defaultExit=4
        elif [ "$verb" == "resolve" ]; then
          defaultExit=2
        elif [ "$verb" == "translate" ]; then
          defaultExit=3
        elif [ "$verb" == "build" ]; then
          defaultExit=0
        elif [ "$verb" == "run" ]; then
          defaultExit=0
          if [ "$useHeadings" == "1" ]; then defaultExit=3; fi
        elif [ "$verb" == "test" ]; then
          defaultExit=2
        elif [ "$verb" == "legacy" ]; then
          defaultExit=0
          if [ "$useHeadings" == "1" ]; then defaultExit=3; fi
          if [ "$defaultCommand" == "%check-resolve" ]; then defaultExit=2 ; fi
        fi
        if [ "$verb" == "legacy" ]; then 
          dOptions=$legacyOptions
          verb= 
        fi
        if [ -z "$expectedExit" ]; then expectedExit=$defaultExit ; fi
        if [ "$coverage" == "1" ] ; then
          f=$outdir/$(basename $file)_${n}.dfy
          if  [ "$command" == "%check-legacy" ]; then
            echo "// RUN: %exits-with" $expectedExit "%baredafny" "/showSnippets:0" $verb $dOptions ${options[@]} '"%s" > "%t"' > "$f"
            echo " " >> $f
            cat $text >> $f
          elif [ "$command" == "%check-cli" ]; then
            echo "// RUN: %exits-with $expectedExit %bare`cat $text` > /dev/null 2> /dev/null" > $f
          else
            echo "// RUN: %exits-with $expectedExit %baredafny $verb $dOptions ${options[@]}" '"%s" > "%t"' > "$f"
            echo " " >> "$f"
            cat "$text" >> "$f"
          fi
        else
          if [ "$command" == "%check-legacy" ]; then
            isverbose=-compileVerbose:$checkIds
            (cd "$dir"; "$dafny" /showSnippets:0 $dOptions $isverbose ${options[@]} $text   ) > "$actualOut" 2> "$actualError"
          else
            isverbose=
            if [ "$checkIds" == "1" ]; then isverbose="--verbose" ; fi
            ( cd "$dir" ; "$dafny" $verb $isverbose $permOptions $dOptions ${options[@]} $text ) > "$actualOut" 2> "$actualError"
          fi
          actualExit=$?
          if [ "$useHeadings" == "1" ]; then
            if [ "$first" == "1" ]; then
              cat "$actualOut" | grep -E '(Error|Warning):' | head -1 > "$actualMsgs"
            else
              cat "$actualOut" | grep -E '(Error|Warning):' > "$actualMsgs"
            fi
            actualid=
            grep 'ID:' "$actualMsgs" > /dev/null
            if [ "$?" == "0" -a "$checkIds" == "1" ]; then
              num=`cat "$actualMsgs" | sed -e 's/^.*[\(]ID: //' -e 's/[\)]$//' | sort -u | wc -l | sed -e 's/[ \t]*//'`
              if [ "$num" != "1" ]; then
                 echo "UNEXPECTED NUMBER OF DIFFERENT IDS: $num"
                 FAIL=1
              fi
              actualid=`cat "$actualMsgs" | sed -e 's/^.*[\(]ID: //' -e 's/[\)]$//' | sort -u`
            fi
            act=`cat "$actualMsgs" | sed -e 's/^[^:]*: //' -e 's/ [ ]*[\(]ID: .*$//' `
            if [ "$checkIds" == "1" -a "$actualid" != "$expid" -a -n "$msg" ] ; then
              echo ERROR ID MISMATCH "$actualid : $expid"
              cat "$actualMsgs"
            fi
            if [ -n "$msg" ]; then
              dif=`echo "$act" | sed -e "s@$msg@@g" | sed -e 's/[ ]*//'`
              if [ -z "$act" -a "$expectedExit" != "0" ] ; then
                 echo NO ERROR MESSAGE FOUND
                 FAIL=1
              fi
              if [ -n "$dif" ] ; then
                 echo NO MATCH 
                 echo PAT "$msg"
                 echo ACT "$act"
                 echo DIF "$dif"
                 FAIL=1
              fi
              if [ "$actualExit" != "$expectedExit" ]; then
                echo EXPECTED EXIT CODE $expectedExit, got $actualExit
                FAIL=1
              fi
            else 
              if [ -n "$act" ]; then
                echo "EXPECTED NO ERROR, got " $act
                FAIL=1
              fi
              if [ "$actualExit" != "0" ]; then
                echo EXPECTED EXIT CODE 0, got $actualec
                FAIL=1
              fi
            fi
          elif [ -z "$expect" ]; then
            # No output file -- so no error expected
            if [ "$actualExit" != "0" ]; then
              echo "TEST FAILED" $file line $n  $command $expect
              cat "$text"
              cat "$actualOut"
              FAIL=1
            fi
            if [ `cat "$actualOut" | wc -l ` != "2" ]; then
              echo ACTUAL ERROR OUTPUT BUT NONE EXPECTED
              cat "$actualOut"
              FAIL=1
            fi
          else
            if [ "$actualExit" != "$expectedExit" ]; then
              echo EXPECTED EXIT CODE $expectedExit, got $actualExit
              FAIL=1
            fi
            if [ -e "$dir/$expect" ]; then
              diff -b -B "$actualOut" "$dir/$expect"
              if [ "$?" != "0" ]; then
                FAIL=1
                echo Actual output differs from expected
                echo "TEST FAILED" $file line $n  $command $expect
                cat "$text"
                cat "$actualOut"
              fi
            else
              cat "$actualOut"
              FAIL=1
            fi
          fi
        fi
      elif [ "$lang" == "dafny" ]; then
         echo UNKNOWN TEST COMMAND $command
         FAIL=1
      fi
      use=
      command=
      expect=
      expectedExit=
      options=( )
      first=0
      tocheck="$actualOut"
  fi
done < "$file"
rm -rf *.tmp $text.*

if [ "$inblock" == "1" ]; then
  echo UNCLOSED BACKTICK BLOCK
  FAIL=1
fi

if [ "$FAIL" == "1" ] ; then 
  echo "Test Failure: $file"
  ANYFAIL=1
fi

rm -f $text *.tmp
done
exit $ANYFAIL
