#!/bin/sh
# scripts/coverage-tests.sh
# Generate line-coverage reports for trbldoc's shell sources from the test
# suite. Answers "what is the test suite not exercising".
#
# Mechanism: the suite runs the tool via `bash "$TRBLDOC"`, so exporting
# BASH_ENV=scripts/lib/trace-init.sh makes each target process emit an xtrace
# of every executed line. We union the executed lines across the whole run and
# compare against the executable lines in each target source. No modification
# of trbldoc.sh or the tests is required.
#
# POSIX sh; works under mingw bash, WSL bash and Alpine/busybox ash. The traced
# run itself uses bash (the suite already invokes bash), which is one of the
# supported target shells.
#
# Usage:
#   scripts/coverage-tests.sh [-s all|unit|integration] [-o OUTDIR]
#                             [-t "file.sh ..."] [-m MIN_PERCENT]
#
#   -s SUITE       suite to run (default: integration)
#   -o OUTDIR      output directory (default: reports/coverage-<timestamp>)
#   -t LIST        space-separated target source files (default: trbldoc.sh)
#   -m MIN_PERCENT fail (exit 2) if overall coverage is below this (default: 0)

set -u

SELF="$0"
. "$(dirname -- "$0")/lib/common.sh"
tb_resolve_paths "$SELF"

SUITE=integration
OUTDIR=""
TARGETS="trbldoc.sh"
MIN_PERCENT=0

while getopts ":s:o:t:m:h" opt; do
  case "$opt" in
    s) SUITE="$OPTARG" ;;
    o) OUTDIR="$OPTARG" ;;
    t) TARGETS="$OPTARG" ;;
    m) MIN_PERCENT="$OPTARG" ;;
    h) sed -n '2,30p' "$SELF"; exit 0 ;;
    :) tb_die "option -$OPTARG requires an argument" ;;
    \?) tb_die "unknown option -$OPTARG" ;;
  esac
done

tb_require awk
tb_require sort

[ -n "$OUTDIR" ] || OUTDIR="$REPO_ROOT/reports/coverage-$(tb_timestamp)"
case "$OUTDIR" in
  /*|[A-Za-z]:[\\/]*)
    ;;
  *)
    OUTDIR="$REPO_ROOT/$OUTDIR"
    ;;
esac
mkdir -p "$OUTDIR/html" || tb_die "cannot create output dir: $OUTDIR"
JUNIT_DIR="$OUTDIR/junit"; mkdir -p "$JUNIT_DIR"
TRACE_DIR="$OUTDIR/trace"; rm -rf "$TRACE_DIR"; mkdir -p "$TRACE_DIR"

SUITE_DIRS="$(tb_suite_dirs "$SUITE")"
SUITE_DIRS_REL="$(tb_suite_dirs_rel "$SUITE")"

# Basename filter for the trace hook + absolute source paths for reporting.
TRACE_TARGETS=""
SRC_FILES=""
for tf in $TARGETS; do
  TRACE_TARGETS="$TRACE_TARGETS ${tf##*/}"
  case "$tf" in
    /*) p="$tf" ;;
    *)  p="$REPO_ROOT/$tf" ;;
  esac
  [ -f "$p" ] || tb_die "target source not found: $p"
  SRC_FILES="$SRC_FILES $p"
done

# ── run suite under xtrace ───────────────────────────────────────────────────
tb_info "running bats ($SUITE) under coverage instrumentation..."
if tb_bats_usable "$SUITE"; then
  BASH_ENV="$LIB_DIR/trace-init.sh"
  TRBLDOC_TRACE_DIR="$TRACE_DIR"
  TRBLDOC_TRACE_MODE="cov"
  TRBLDOC_TRACE_TARGETS="$TRACE_TARGETS"
  export BASH_ENV TRBLDOC_TRACE_DIR TRBLDOC_TRACE_MODE TRBLDOC_TRACE_TARGETS
  # shellcheck disable=SC2086
  bats --report-formatter junit --output "$JUNIT_DIR" $SUITE_DIRS \
    > "$OUTDIR/bats-output.txt" 2>&1 || tb_info "bats reported failures (see bats-output.txt)"
  unset BASH_ENV TRBLDOC_TRACE_DIR TRBLDOC_TRACE_MODE TRBLDOC_TRACE_TARGETS
elif command -v wsl >/dev/null 2>&1; then
  tb_info "local bats appears unusable; retrying via WSL bats..."
  WSL_REPO="$(tb_to_wsl_path "$REPO_ROOT")"
  WSL_LIB="$(tb_to_wsl_path "$LIB_DIR")"
  WSL_TRACE="$(tb_to_wsl_path "$TRACE_DIR")"
  WSL_JUNIT="$(tb_to_wsl_path "$JUNIT_DIR")"
  wsl -- bash -lc \
    "cd '$WSL_REPO' && export BASH_ENV='$WSL_LIB/trace-init.sh' TRBLDOC_TRACE_DIR='$WSL_TRACE' TRBLDOC_TRACE_MODE='cov' TRBLDOC_TRACE_TARGETS='$TRACE_TARGETS'; bats --report-formatter junit --output '$WSL_JUNIT' $SUITE_DIRS_REL" \
    > "$OUTDIR/bats-output.txt" 2>&1 || tb_info "bats (WSL) reported failures (see bats-output.txt)"
else
  tb_die "local bats command appears unusable and no WSL fallback is available"
fi

if ! ls "$TRACE_DIR"/trace.*.log >/dev/null 2>&1; then
  if grep -qi "bash\\\\r" "$OUTDIR/bats-output.txt" 2>/dev/null; then
    tb_die "bats appears broken (CRLF shebang: 'bash\\r'). Reinstall bats or run dos2unix on the bats scripts, then retry."
  fi
  tb_die "no trace data captured; ensure bats actually runs tests (see $OUTDIR/bats-output.txt)"
fi

# ── union executed lines ─────────────────────────────────────────────────────
awk -f "$LIB_DIR/trace-extract.awk" -v MODE=cov "$TRACE_DIR"/trace.*.log \
  | sort -u > "$OUTDIR/covered.tsv"

# ── per-file coverage report + summary ───────────────────────────────────────
# shellcheck disable=SC2086
awk -f "$LIB_DIR/coverage-report.awk" \
  -v COVERED="$OUTDIR/covered.tsv" \
  -v HTMLDIR="$OUTDIR/html" \
  $SRC_FILES > "$OUTDIR/summary.rows"

{
  printf 'file,executable,covered,percent\n'
  cat "$OUTDIR/summary.rows"
} > "$OUTDIR/summary.csv"

awk -f "$LIB_DIR/render-coverage-index.awk" \
  -v TITLE="trbldoc coverage ($SUITE)" \
  "$OUTDIR/summary.rows" > "$OUTDIR/index.html"

# ── overall percent + threshold gate ─────────────────────────────────────────
OVERALL="$(awk -F',' '{t+=$2; c+=$3} END{ if(t>0) printf "%.1f", c*100.0/t; else print "0.0" }' "$OUTDIR/summary.rows")"

printf '\n==== coverage summary (%s) ====\n' "$SUITE"
awk -F',' '{ printf "%6.1f%%  %-20s (%d/%d)\n", $4, $1, $3, $2 }' "$OUTDIR/summary.rows"
printf '  overall: %s%%\n' "$OVERALL"
printf '\nReports written to: %s\n' "$OUTDIR"
printf '  coverage index: %s\n' "$OUTDIR/index.html"

# Threshold enforcement (integer or decimal compare via awk).
if awk -v o="$OVERALL" -v m="$MIN_PERCENT" 'BEGIN{ exit !(m>0 && o+0 < m+0) }'; then
  tb_die "coverage ${OVERALL}% is below the required minimum ${MIN_PERCENT}%"
fi