#!/usr/bin/env bash
# Test coverage collection and threshold enforcement.
#
# Runs Rust tests with llvm-cov and frontend tests with vitest --coverage.
# Reports line coverage percentages for each.
#
# After collecting coverage, writes a language-agnostic .coverage_report.json
# at the project root in the standard format:
#
#   {
#     "overall": <float>,
#     "threshold": <float>,
#     "files": [{ "path": <string>, "coverage": <float> }]
#   }
#
# Threshold: reads from COVERAGE_THRESHOLD env var, or .coverage_baseline file.
# Default: 0% (any coverage passes; baseline is written on first run).
#
# Coverage can only go up: if current coverage is above the stored baseline,
# the baseline is updated automatically.
#
# Exit codes:
#   0 — all coverage at or above threshold
#   1 — coverage below threshold

set -uo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
BASELINE_FILE="$PROJECT_ROOT/.coverage_baseline"
RUST_COV_JSON="$PROJECT_ROOT/.coverage_rust_raw.json"

# ── Load threshold ────────────────────────────────────────────────────────────
if [ -n "${COVERAGE_THRESHOLD:-}" ]; then
    THRESHOLD="$COVERAGE_THRESHOLD"
elif [ -f "$BASELINE_FILE" ]; then
    THRESHOLD=$(cat "$BASELINE_FILE")
else
    THRESHOLD=0
fi

echo "=== Coverage threshold: ${THRESHOLD}% ==="
echo ""

PASS=true
RUST_LINE_COV=0
FRONTEND_LINE_COV=0

# ── Rust coverage ─────────────────────────────────────────────────────────────
echo "=== Running Rust tests with coverage ==="
if cargo llvm-cov --version >/dev/null 2>&1; then
    # Run tests and generate both a text summary and a JSON report for per-file data.
    cargo llvm-cov \
        --manifest-path "$PROJECT_ROOT/Cargo.toml" \
        --summary-only \
        2>&1

    # Generate JSON report from the already-collected profdata (no re-run).
    cargo llvm-cov report \
        --manifest-path "$PROJECT_ROOT/Cargo.toml" \
        --json \
        --output-path "$RUST_COV_JSON" \
        >/dev/null 2>&1 || true

    # Parse overall Rust line coverage from the JSON (more reliable than awk on text).
    if [ -f "$RUST_COV_JSON" ]; then
        RUST_LINE_COV=$(python3 -c "
import json, sys
with open('$RUST_COV_JSON') as f:
    data = json.load(f)
pct = data['data'][0]['totals']['lines']['percent']
print(f'{pct:.1f}')
" 2>/dev/null) || RUST_LINE_COV=0
    fi
else
    echo "cargo-llvm-cov not available; skipping Rust coverage"
fi
echo "Rust line coverage: ${RUST_LINE_COV}%"
echo ""

# ── Frontend coverage ─────────────────────────────────────────────────────────
echo "=== Running frontend tests with coverage ==="
FRONTEND_DIR="$PROJECT_ROOT/frontend"
FRONTEND_LINE_COV=0
if [ -d "$FRONTEND_DIR" ]; then
    (cd "$FRONTEND_DIR" && npm run test:coverage 2>&1) || true

    # Parse overall from vitest's json-summary report (more reliable than text table).
    FRONTEND_SUMMARY="$FRONTEND_DIR/coverage/coverage-summary.json"
    if [ -f "$FRONTEND_SUMMARY" ]; then
        FRONTEND_LINE_COV=$(python3 -c "
import json
with open('$FRONTEND_SUMMARY') as f:
    data = json.load(f)
pct = data['total']['lines']['pct']
print(f'{pct:.1f}')
" 2>/dev/null) || FRONTEND_LINE_COV=0
    fi
else
    echo "No frontend/ directory found; skipping frontend coverage"
fi
echo "Frontend line coverage: ${FRONTEND_LINE_COV}%"
echo ""

# ── Overall (average of available measurements) ───────────────────────────────
if [ "$RUST_LINE_COV" != "0" ] && [ "$FRONTEND_LINE_COV" != "0" ]; then
    OVERALL=$(awk "BEGIN { printf \"%.1f\", ($RUST_LINE_COV + $FRONTEND_LINE_COV) / 2 }")
elif [ "$RUST_LINE_COV" != "0" ]; then
    OVERALL="$RUST_LINE_COV"
elif [ "$FRONTEND_LINE_COV" != "0" ]; then
    OVERALL="$FRONTEND_LINE_COV"
else
    OVERALL=0
fi

# ── Summary ───────────────────────────────────────────────────────────────────
echo "=== Coverage Summary ==="
echo "  Rust:     ${RUST_LINE_COV}%"
echo "  Frontend: ${FRONTEND_LINE_COV}%"
echo "  Overall:  ${OVERALL}%"
echo "  Threshold: ${THRESHOLD}%"
echo ""

# ── Threshold check ───────────────────────────────────────────────────────────
if awk "BEGIN { exit (($OVERALL + 0) < ($THRESHOLD + 0)) ? 0 : 1 }"; then
    echo "FAIL: Coverage ${OVERALL}% is below threshold ${THRESHOLD}%"
    PASS=false
else
    echo "PASS: Coverage ${OVERALL}% meets threshold ${THRESHOLD}%"
fi

# ── Update baseline when coverage improves ────────────────────────────────────
if [ "$PASS" = "true" ]; then
    STORED_BASELINE="${THRESHOLD}"
    if awk "BEGIN { exit (($OVERALL + 0) > ($STORED_BASELINE + 0)) ? 0 : 1 }"; then
        echo "${OVERALL}" > "$BASELINE_FILE"
        echo "Baseline updated: ${STORED_BASELINE}% → ${OVERALL}%"
    fi
fi

# ── Write .coverage_report.json ───────────────────────────────────────────────
# This language-agnostic JSON file is consumed by the huskies `coverage` bot
# command to show per-file improvement targets without any language-specific
# logic in the server.
FRONTEND_SUMMARY="${FRONTEND_DIR}/coverage/coverage-summary.json"

OVERALL_VAL="$OVERALL" \
THRESHOLD_VAL="$THRESHOLD" \
RUST_COV_JSON="$RUST_COV_JSON" \
FRONTEND_SUMMARY="$FRONTEND_SUMMARY" \
PROJECT_ROOT="$PROJECT_ROOT" \
python3 - << 'PYEOF'
import json, os, sys

overall = float(os.environ["OVERALL_VAL"])
threshold = float(os.environ["THRESHOLD_VAL"])
rust_json = os.environ["RUST_COV_JSON"]
frontend_summary = os.environ["FRONTEND_SUMMARY"]
project_root = os.environ["PROJECT_ROOT"] + "/"

files = []

# Collect per-file Rust coverage from cargo llvm-cov JSON output.
if os.path.exists(rust_json):
    with open(rust_json) as f:
        data = json.load(f)
    for file_entry in data["data"][0]["files"]:
        path = file_entry["filename"]
        if path.startswith(project_root):
            path = path[len(project_root):]
        pct = file_entry["summary"]["lines"]["percent"]
        files.append({"path": path, "coverage": round(pct, 2)})

# Collect per-file frontend coverage from vitest json-summary output.
if os.path.exists(frontend_summary):
    with open(frontend_summary) as f:
        data = json.load(f)
    for key, value in data.items():
        if key == "total":
            continue
        path = key
        if path.startswith(project_root):
            path = path[len(project_root):]
        pct = value["lines"]["pct"]
        files.append({"path": path, "coverage": round(pct, 2)})

report = {
    "overall": overall,
    "threshold": threshold,
    "files": sorted(files, key=lambda x: x["coverage"]),
}

output_path = os.path.join(project_root, ".coverage_report.json")
with open(output_path, "w") as f:
    json.dump(report, f, indent=2)
    f.write("\n")

print(f"Coverage report written: .coverage_report.json ({len(files)} files)")
PYEOF

# ── Cleanup temp files ────────────────────────────────────────────────────────
rm -f "$RUST_COV_JSON"

if [ "$PASS" = "false" ]; then
    exit 1
fi