#!/bin/sh
set -eu

tool=${1:-zig-out/bin/pick}
tmp=${TMPDIR:-.zig-cache}/pick-smoke.$$
mkdir -p "$tmp"
trap 'rm -rf "$tmp"' EXIT HUP INT TERM

# req: pick/008
# req: pick/009
# req: pick/010

assert_eq() {
  want=$1
  got=$2
  cmp "$want" "$got"
}

assert_empty() {
  file=$1
  if [ -s "$file" ]; then
    echo "pick: expected empty file: $file" >&2
    exit 1
  fi
}

assert_fails() {
  if "$@"; then
    echo "pick: command unexpectedly succeeded: $*" >&2
    exit 1
  fi
}

# Numeric field selection preserves records and stdout contains only selected TSV.
printf 'a\tb\tc\n1\t2\t3\n' | "$tool" 2 > "$tmp/pick-one.out"
printf 'b\n2\n' > "$tmp/pick-one.want"
assert_eq "$tmp/pick-one.want" "$tmp/pick-one.out"

# Header selection emits the selected header and selected data columns.
printf 'path\tsize\tkind\na\t10\tfile\n' | "$tool" --header path size > "$tmp/pick-header.out"
printf 'path\tsize\na\t10\n' > "$tmp/pick-header.want"
assert_eq "$tmp/pick-header.want" "$tmp/pick-header.out"

# Missing fields are empty fields, not pipeline failures.
printf 'a\tb\n1\n' | "$tool" 1 2 > "$tmp/pick-missing.out"
printf 'a\tb\n1\t\n' > "$tmp/pick-missing.want"
assert_eq "$tmp/pick-missing.want" "$tmp/pick-missing.out"

# CRLF input is accepted and normalized to LF records.
printf 'a\tb\r\n1\t2\r\n' | "$tool" 2 > "$tmp/pick-crlf.out"
printf 'b\n2\n' > "$tmp/pick-crlf.want"
assert_eq "$tmp/pick-crlf.want" "$tmp/pick-crlf.out"

# A record longer than the internal read buffer still streams correctly across
# chunk boundaries without whole-input buffering.
: > "$tmp/pick-long.in"
i=0
while [ "$i" -lt 9000 ]; do
  printf x >> "$tmp/pick-long.in"
  i=$((i + 1))
done
printf '\tb\n' >> "$tmp/pick-long.in"
"$tool" 2 < "$tmp/pick-long.in" > "$tmp/pick-long.out"
printf 'b\n' > "$tmp/pick-long.want"
assert_eq "$tmp/pick-long.want" "$tmp/pick-long.out"

# Help is stdout-only and successful.
"$tool" --help > "$tmp/pick-help.out" 2> "$tmp/pick-help.err"
grep -q '^usage: pick' "$tmp/pick-help.out"
assert_empty "$tmp/pick-help.err"

# Usage errors are stderr-only and nonzero.
assert_fails "$tool" > "$tmp/pick-noargs.out" 2> "$tmp/pick-noargs.err"
assert_empty "$tmp/pick-noargs.out"
grep -q '^usage: pick' "$tmp/pick-noargs.err"

assert_fails "$tool" 0 > "$tmp/pick-zero.out" 2> "$tmp/pick-zero.err"
assert_empty "$tmp/pick-zero.out"
grep -q 'fields are 1-based' "$tmp/pick-zero.err"

assert_fails "$tool" nope > "$tmp/pick-invalid.out" 2> "$tmp/pick-invalid.err"
assert_empty "$tmp/pick-invalid.out"
grep -q 'invalid field' "$tmp/pick-invalid.err"

# Forbidden near miss: option-looking regex/expression input is rejected as data,
# not interpreted as another command language.
assert_fails "$tool" --regex '.*' > "$tmp/pick-regex.out" 2> "$tmp/pick-regex.err"
assert_empty "$tmp/pick-regex.out"
grep -q 'invalid field' "$tmp/pick-regex.err"

# Head-style consumers may close stdout early; that must not pollute stderr.
i=0
{
  while [ "$i" -lt 20000 ]; do
    printf 'a\tb\n'
    i=$((i + 1))
  done
} | "$tool" 1 2> "$tmp/pick-head.err" | sed 1q > "$tmp/pick-head.out"
printf 'a\n' > "$tmp/pick-head.want"
assert_eq "$tmp/pick-head.want" "$tmp/pick-head.out"
assert_empty "$tmp/pick-head.err"