#!/usr/bin/env bash
#
# coverage-gate.sh — T-iOS-16 per-package OWN-SOURCES coverage gate (>= 80%).
#
# Usage:   coverage-gate.sh <PackageName>          # e.g. coverage-gate.sh WireProtocol
# Env:     COVERAGE_THRESHOLD=<percent>            # default 80 (red/green demo knob)
#
# WHY THIS EXISTS (plan §9 flaw, fix assigned to T-iOS-16): the raw §9 command
#   xcrun llvm-cov export -summary-only ... -ignore-filename-regex '(Tests|TestSupport|\.build)/'
#   | jq '.data[0].totals.lines.percent >= 80'
# reads the export TOTALS, which include every STATICALLY-LINKED DEPENDENCY
# source compiled into the test binary (e.g. WireProtocol sources inside
# SessionCore's test run). That lets a package's own weak coverage hide behind a
# well-covered dependency (or vice versa). The corrected filter below keeps ONLY
# files under Packages/<P>/Sources/ (excluding *Placeholder* scaffolding) and
# recomputes line coverage from the per-file summaries.
#
# Exit codes: 0 = gate passed; 1 = below threshold, filter matched no sources,
# or any build/test failure (set -e).

set -euo pipefail

PKG="${1:?usage: coverage-gate.sh <PackageName> (WireProtocol|SessionCore|HostRegistry|APIClient)}"
THRESHOLD="${COVERAGE_THRESHOLD:-80}"

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
PKG_DIR="$REPO_ROOT/ios/Packages/$PKG"

if [ ! -d "$PKG_DIR" ]; then
    echo "coverage-gate($PKG): package dir not found: $PKG_DIR" >&2
    exit 1
fi

# 1) Run the package tests with coverage instrumentation (test failure => gate red).
swift test --package-path "$PKG_DIR" --enable-code-coverage

# 2) Locate the test binary and the merged profile (paths per plan §9).
BIN="$(swift build --package-path "$PKG_DIR" --show-bin-path)/${PKG}PackageTests.xctest/Contents/MacOS/${PKG}PackageTests"
PROF="$(dirname "$(swift test --package-path "$PKG_DIR" --show-codecov-path)")/default.profdata"

# 3) Export per-file summaries and keep ONLY this package's own production
#    sources: path must contain /Packages/<PKG>/Sources/ and must not be a
#    *Placeholder* scaffold file. Dependency sources (other packages), Tests/,
#    TestSupport and .build shims all fail the path filter automatically.
read -r COVERED TOTAL < <(
    xcrun llvm-cov export -summary-only "$BIN" -instr-profile "$PROF" \
        | jq -r --arg pkg "$PKG" '
            [.data[0].files[]
              | select(.filename | contains("/Packages/" + $pkg + "/Sources/"))
              | select(.filename | contains("Placeholder") | not)
              | .summary.lines]
            | "\(map(.covered) | add // 0) \(map(.count) | add // 0)"'
)

if [ "$TOTAL" -eq 0 ]; then
    echo "coverage-gate($PKG): FAIL — filter matched no own-source files under" \
        "Packages/$PKG/Sources/ (filter bug or empty package?)" >&2
    exit 1
fi

# LC_ALL=C on both awk calls: a comma-decimal locale would print "100,00",
# which awk then compares as a STRING against the threshold (silent false FAIL).
PCT="$(LC_ALL=C awk -v c="$COVERED" -v t="$TOTAL" 'BEGIN { printf "%.2f", c * 100 / t }')"
echo "coverage-gate($PKG): own-sources line coverage ${PCT}% (${COVERED}/${TOTAL} lines, threshold ${THRESHOLD}%)"

if ! LC_ALL=C awk -v p="$PCT" -v th="$THRESHOLD" 'BEGIN { exit !(p >= th) }'; then
    echo "coverage-gate($PKG): FAIL — below threshold ${THRESHOLD}%" >&2
    exit 1
fi

echo "coverage-gate($PKG): PASS"