#!/bin/sh

# Run hledger-ui in the background without needing an interactive
# terminal, passing through any arguments, and dump its first screen*
# as cleaned up plain text. This allows scripts to run hledger-ui and
# capture its output.
# * Or, all output from inputs hard-coded below.
#
# Here's some sample output for "test/hledgeruicapture -f examples/sample.journal"
# showing the initial output (accounts screen) then the outputs from four inputs: 
# RIGHT (draws register screen)
# UP    (moves selection up one row; only the heading and old/new rows are redrawn)
# LEFT  (draws accounts screen again)
# 1     (redraws accounts screen with depth limit 1).
# Note,
# - only lines which have been redrawn are shown (and perhaps redrawing parts of lines is also possible)
# - all inputs above cause the top line to be redrawn, which helps distinguish the outputs
# - the top line's border chars are converted to ---
# - empty lines and the bottom line (help & border) are omitted
#
# --- sample.journal account balances (1/8)
#  assets:bank:checking    0
#  assets:bank:saving     $1
#  assets:cash           $-2
#  expenses:food          $1
#  expenses:supplies      $1
#  income:gifts          $-1
#  income:salary         $-1
#  liabilities:debts      $1
# --- assets:bank:checking transactions (4/4)
#  2008-01-01   income                           in:salary                          $1   $1
#  2008-06-01   gift                             in:gifts                           $1   $2
#  2008-06-02   save                             as:ba:saving                      $-1   $1
#  2008-12-31 * pay off                          li:debts                          $-1    0
# --- assets:bank:checking transactions (3/4)
#  2008-06-02   save                             as:ba:saving                      $-1   $1
#  2008-12-31 * pay off                          li:debts                          $-1    0
# --- sample.journal account balances (1/8)
#  assets:bank:checking    0
#  assets:bank:saving     $1
#  assets:cash           $-2
#  expenses:food          $1
#  expenses:supplies      $1
#  income:gifts          $-1
#  income:salary         $-1
#  liabilities:debts      $1
# --- sample.journal account balances to depth 1 (1/4)
#  assets       $-1
#  expenses      $2
#  income       $-2
#  liabilities   $1
#
#
# Todo:
# - allow a sequence of inputs to be provided. Eg, first line of stdin
#   is hledger-ui arguments, and each following line is an input.
#
#
# Requirements:
# - empty (http://empty.sourceforge.net) is used as a (complicated,
#   delicate) way of running hledger-ui from a non-interactive script.
#   It is included in tools/empty/ and should be installed in PATH. It
#   seemed simpler than using expect (but maybe isn't).

# For debugging:
# watch -n0.2 "pgrep -fl '(empty|hledger-ui)' | grep -v watch"
# https://www.linuxjournal.com/article/2156

# Convert a stream of hledger-ui ANSI output captured by empty
# to a plain text sequence of outputs, suitable for tests.
# Based on https://unix.stackexchange.com/a/4529/286158, Term::ANSIColor
# First regex: 
# 1. convert "move to first column" escape sequences to newlines
# 2. strip remaining escape sequences
# 3. (replace empty's <<< delimiters with newlines - not any more, where have they gone ?)
# 4. add a final newline
# Second regex (because I couldn't fix newline matching in the first):
# 1. replace screen-width dash borders with short hyphen delimiters
# 2. strip trailing spaces on each line
# 3. hide empty lines
# 4. hide each screen's bottom help line
hledgerui2txt()
{
    perl -pe 's/\e\[\d+;1H/\n/g; s/\e\[?.*?[\@-~]//g; s/$/\n/;' | \
    perl -ne 's/(─)+/---/; s/(─)+//; s/ +$//; print unless /^$/ or /q:quit/'
}

# Be sure not to leave empty and/or hledger-ui running if this script is killed.
# (Doesn't prevent occasional "Fatal open FIFO ... No such file or directory" errors.)
cleanup() {
    (echo; echo "hledgeruicapture: interrupted, cleaning up") >&2
    if [[ -e p$$ ]]; then PID=$(cat p$$); kill $PID; rm -f c$$; fi
}
trap cleanup INT QUIT TERM

# Start hledger-ui (and empty's monitor process) in the background,
# specifying input/output FIFOs (with process-specific names in case
# of concurrent testing). We don't use empty's default FIFOs because
# finding their paths in a script is a hassle.
empty -f -i i$$ -o o$$ -p p$$ hledger-ui "$@"

# Wait for the first screen's final line (containing "q:quit"), then
# send 'q' causing hledger-ui to exit.
# Doesn't work if the line has already been displayed when this runs.
#empty -w -t 1 -i o$$ -o i$$ q:quit q

# Wait long enough to ensure the first screen has rendered
# (assuming no crazy large data is being displayed).
sleep 0.1

# # Testing: send some other stuff
# U=$'\e[A'
# D=$'\e[B'
# R=$'\e[C'
# L=$'\e[D'
# empty -s -o i$$ $R; sleep 0.1
# empty -s -o i$$ $U; sleep 0.1
# empty -s -o i$$ $L; sleep 0.1
# empty -s -o i$$ 1; sleep 0.1
# empty -s -o i$$ 2; sleep 0.1
# empty -s -o i$$ 3; sleep 0.1
# empty -s -o i$$ 1; sleep 0.1

# capture the output FIFO's content in a file, before hledger-ui quits ?
# hangs until ctrl-c, why ?
#cat o$$ #> c$$

# Send 'q' on the input FIFO, causing hledger-ui to exit.
empty -s -o i$$ q
# But wait until after the pipe has been read, below ? Doesn't help.
# (sleep 1; empty -s -o i$$ q) &

# drain the output FIFO one last time, allowing empty monitor to exit ? no
#cat o$$

# kill empty's monitor process deliberately ? no
#empty -k `cat p$$`


# Read all from the output FIFO, causing empty's monitor to exit and
# clean up the FIFOs. And convert it to plain text.

# can never get empty -r to work right
##empty -r -b 10000 -t 10 -i o$$ | hledgerui2txt

# cat works..
# but only when running interactively. When non-interactive
# (eg echo | ./uitest), the FIFO returns nothing. Could be "If all
# file descriptors referring to the write end of a pipe have been
# closed, then an attempt to read(2) from the pipe will see
# end-of-file (read(2) will return 0)"
cat o$$ | hledgerui2txt

# convert the captured output, and clean up
# cat c$$ | hledgerui2txt
# rm c$$