#!/usr/bin/env rc

nl='
'
debounce=2
nextok=()
once=0
model=()
target=()

fn usage {
	echo 'usage: todowatch.rc [-h] [--model model] [file-or-directory]' >[1=2]
	echo 'try: todowatch.rc --help' >[1=2]
	exit usage
}

fn help {
	cat <<'---'
todowatch - watch files and run TODO(ai) tasks with opencode

usage: todowatch.rc [-h] [--model model] [file-or-directory]

With no argument, the script watches the current directory.
Give a directory name to watch a whole tree.
Give a file name to watch one file.

How it works:

- The script waits for edits with entr or inotifywait.
- After an edit, it searches the files for the exact text TODO(ai): .
- The task text starts after the marker on that line.
- Comment lines below the marker continue the task.
  The script treats these prefixes as comments:
  //  #  --  ;  *  block comments  <!-- -->
- A blank line can sit inside the task.
- A code line, or two blank lines in a row, end the task.

The script then runs one command per task:

  opencode run "Do the following TODO(ai) task: <task> File: <path>:<line>"

<path> is relative to the directory where you started the script.
Use --model to select the opencode model for each task.

Notes:

- The script waits 2 seconds after each edit before it acts.
  Change the debounce value at the top of the script to adjust this.
- You need ripgrep, awk, entr or inotifywait, and opencode.
---
}

while(! ~ $1 ()){
	switch($1){
	case -h --help
		help
		exit 0
	case --once
		once=1
	case --model
		if(~ $#* 1)
			usage
		shift
		model=$1
	case --*
		usage
	case *
		if(! ~ $#target 0)
			usage
		target=$1
	}
	shift
}
if(~ $#target 0)
	target=.
if(! test -e $target){
	usage
}

fn todotext {
	file=$1
	start=$2
	awk -v start=$start -f /dev/stdin $file <<'awk'
# Collect a TODO(ai) task that starts on line "start" of the file.
# The task continues on comment lines below it. A code line ends the task.

# Append s to the result and stop reading. END then prints the result.
function done(s){ if(s!="") out=out "\n" s; exit }

# The TODO line: keep only the text after the marker.
NR==start{
	out=$0
	sub(/.*TODO\(ai\): /,"",out)
	p=$0
	sub(/^[ \t]+/,"",p)
	inblock=0
	if(p~/^\/\*/){
		t=p
		sub(/^\/\*/,"",t)
		inblock=(t!~/\*\//)
	}
	next
}

# Each line after the TODO line.
NR>start{
	trim=$0
	sub(/\r$/,"",trim)
	sub(/^[ \t]+/,"",trim)

	# One blank line is allowed inside the task.
	# Two blank lines in a row end the task.
	if(trim==""){
		if(++blank>=2) exit
		next
	}

	l=trim

	# Inside a /* block: strip the * at the start of each line.
	# A */ ends the task; keep any text before it.
	if(inblock){
		sub(/^\*+[ \t]?/,"",l)
		if(l~/\*\/[ \t]*$/){
			sub(/[ \t]*\*\/[ \t]*$/,"",l)
			done(l)
		}
		if(l!=""){out=out "\n" l; blank=0}
		next
	}

	# A new /* here opens a block. If it closes on this same line,
	# keep the text before */ and stop.
	if(l~/^\/\*/){
		sub(/^\/\*/,"",l)
		if(l~/\*\/[ \t]*$/){
			sub(/[ \t]*\*\/[ \t]*$/,"",l)
			done(l)
		}
		inblock=1
		if(l!=""){out=out "\n" l; blank=0}
		next
	}

	# HTML comments: <!-- opens, --> closes and stops the task.
	html=0
	if(l~/^<!--/){html=1; sub(/^<!--/,"",l)}
	if(l~/-->[ \t]*$/){html=1; sub(/[ \t]*-->[ \t]*$/,"",l)}

	# Line comments in most languages: // # -- ;;
	mark=0
	if(l~/^(\/\/|#|--|;+)/){mark=1; sub(/^(\/\/|#|--|;+)[ \t]?/,"",l)}

	# A comment line adds its text to the task.
	# Any other line, for example code, ends the task.
	if(html || mark){
		if(l!=""){out=out "\n" l; blank=0}
		if(html && trim~/-->[ \t]*$/) exit
		next
	}
	exit
}

END{print out}
awk
}

fn scan {
	now=`{date +%s}
	if(! ~ $#nextok 0 && test $now -lt $nextok)
		return
	nextok=`{expr $now + $debounce}

	locs=()
	ifs=$nl{
		if(test -f $target){
			locs=`{rg -n --with-filename --no-heading 'TODO\(ai\): ' $target >[2]/dev/null | cut -d: -f1-2}
		} else {
			files=`{rg --files $target >[2]/dev/null}
			if(! ~ $#files 0)
				locs=`{rg -n --with-filename --no-heading 'TODO\(ai\): ' $files >[2]/dev/null | cut -d: -f1-2}
		}
	}
	if(~ $#locs 0)
		return
	cwd=`{pwd}
	ifs=$nl{
		for(loc in $locs){
			f=`{echo $loc | cut -d: -f1}
			n=`{echo $loc | cut -d: -f2}
			ifs=''{text=`{todotext $f $n}}
			if(! ~ $#text 0){
				rel=`{printf %s $f | sed s@^$cwd/@@}
				msg='Do the following TODO(ai) task:' ^ $nl ^ $text ^ $nl ^ $nl ^ 'File: '$rel:$n
				args=()
				if(! ~ $#model 0)
					args=(--model $model)
				opencode run $args $^msg
			}
		}
	}
}

if(~ $once 1){
	scan
	exit 0
}

watcher=()
if(which inotifywait >/dev/null >[2=1]){
	watcher=inotifywait
} else if(which entr >/dev/null >[2=1]){
	watcher=entr
}
if(~ $#watcher 0){
	echo 'todowatch: install entr or inotifywait' >[1=2]
	exit deps
}

if(~ $watcher inotifywait){
	excl='(^|/)(\.git|node_modules)(/|$)'
	args=(-q -m -e close_write,moved_to --format %w%f --exclude $excl)
	if(test -d $target)
		args=(-r $args)
	$args $target | for(f){scan}
} else {
	while(true){
		files=()
		ifs=$nl{
			if(test -f $target){files=($target)} else {files=`{rg --files $target >[2]/dev/null}}
		}
		args=($0 --once)
		if(! ~ $#model 0)
			args=($args --model $model)
		if(! ~ $#files 0)
			{for(f in $files) echo $f} | entr -d $args $target
		sleep 1
	}
}