#!/bin/bash
set -euo pipefail

# Edge Case Tests for Coverage Enforcement Script
# Tests floating-point comparisons, missing dependencies, empty reports, etc.

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

TESTS_PASSED=0
TESTS_FAILED=0

print_test() {
    printf "${BLUE}[TEST]${NC} %s\n" "$1"
}

pass() {
    printf "${GREEN}✓ PASS${NC} %s\n" "$1"
    TESTS_PASSED=$((TESTS_PASSED + 1))
}

fail() {
    printf "${RED}✗ FAIL${NC} %s\n" "$1"
    TESTS_FAILED=$((TESTS_FAILED + 1))
}

# Test 1: Floating-point comparison with bc -l
test_floating_point_comparison() {
    print_test "Floating-point comparison accuracy"

    # Test edge cases for coverage comparisons
    local test_cases=(
        "59.9 60 1"  # Just below threshold (should be less)
        "60.0 60 0"  # Exactly at threshold (should NOT be less)
        "60.1 60 0"  # Just above threshold (should NOT be less)
        "74.9 75 1"  # Just below target (should be less)
        "75.0 75 0"  # Exactly at target (should NOT be less)
        "0.0 60 1"   # Zero coverage (should be less)
        "100.0 60 0" # Perfect coverage (should NOT be less)
    )

    for test_case in "${test_cases[@]}"; do
        local value=$(echo "$test_case" | cut -d' ' -f1)
        local threshold=$(echo "$test_case" | cut -d' ' -f2)
        local expected=$(echo "$test_case" | cut -d' ' -f3)

        local result=0
        if (( $(echo "$value < $threshold" | bc -l) )); then
            result=1
        fi

        if [ "$result" -eq "$expected" ]; then
            pass "Comparison: $value < $threshold = $result (expected $expected)"
        else
            fail "Comparison: $value < $threshold = $result (expected $expected)"
        fi
    done
}

# Test 2: Handle missing llvm-cov gracefully
test_missing_llvm_cov() {
    print_test "Missing llvm-cov dependency handling"

    # Test that the enforcement script checks for cargo-llvm-cov
    if grep -q "command -v cargo-llvm-cov" scripts/enforce_coverage.sh; then
        pass "Script checks for cargo-llvm-cov availability"
    else
        fail "Script does not check for cargo-llvm-cov"
        return
    fi

    # Test that script exits on missing dependency
    if grep -A 3 "command -v cargo-llvm-cov" scripts/enforce_coverage.sh | grep -q "exit 1"; then
        pass "Script exits gracefully when cargo-llvm-cov is missing"
    else
        fail "Script does not exit when cargo-llvm-cov is missing"
    fi

    # Test for user-friendly error message
    if grep -A 3 "cargo-llvm-cov not found" scripts/enforce_coverage.sh | grep -q "Install with"; then
        pass "Script provides installation instructions for missing dependency"
    else
        fail "Script does not provide installation instructions"
    fi
}

# Test 3: Handle empty coverage reports
test_empty_coverage_report() {
    print_test "Empty coverage report handling"

    # Create a temporary empty JSON file
    local temp_json="/tmp/empty_coverage.json"
    echo '{"data":[]}' > "$temp_json"

    # Test extraction from empty report
    local lines_covered=$(jq '.data[0].totals.lines.covered' "$temp_json" 2>/dev/null || echo "0")
    local lines_total=$(jq '.data[0].totals.lines.count' "$temp_json" 2>/dev/null || echo "1")

    if [ "$lines_covered" == "null" ] || [ "$lines_covered" == "0" ]; then
        pass "Empty report handled without crash (coverage=$lines_covered)"
    else
        fail "Empty report not handled properly"
    fi

    rm "$temp_json"
}

# Test 4: Handle malformed JSON gracefully
test_malformed_json() {
    print_test "Malformed JSON handling"

    # Create a malformed JSON file
    local temp_json="/tmp/malformed.json"
    echo '{invalid json' > "$temp_json"

    # Test jq error handling
    if jq '.data[0].totals.lines.covered' "$temp_json" 2>/dev/null; then
        fail "Malformed JSON not detected"
    else
        pass "Malformed JSON detected and handled"
    fi

    rm "$temp_json"
}

# Test 5: Handle division by zero
test_division_by_zero() {
    print_test "Division by zero protection"

    # Test with zero total lines
    local lines_covered=0
    local lines_total=0

    # The script should check for zero before dividing
    if [ "$lines_total" == "0" ]; then
        pass "Zero division prevented (total lines = 0)"
    else
        fail "Zero division check failed"
    fi

    # Test bc division by zero
    local result=$(echo "scale=2; 10 / 1" | bc 2>/dev/null || echo "ERROR")
    if [ "$result" != "ERROR" ]; then
        pass "bc calculation works with valid divisor"
    else
        fail "bc calculation failed with valid divisor"
    fi
}

# Test 6: Module-level threshold validation
test_module_threshold_validation() {
    print_test "Module-level threshold validation"

    # Production modules should have 75% threshold
    local production_modules=(
        "trading_engine"
        "risk"
        "config"
        "common"
        "services/trading_service"
        "services/api_gateway"
    )

    # Test threshold assignment logic
    for module in "${production_modules[@]}"; do
        local is_production=false

        # Check if module matches production pattern (simulating script logic)
        for prod_module in "${production_modules[@]}"; do
            if [[ "$module" == *"$prod_module"* ]]; then
                is_production=true
                break
            fi
        done

        if [ "$is_production" = true ]; then
            pass "Module $module correctly identified as production"
        else
            fail "Module $module not identified as production"
        fi
    done
}

# Test 7: Handle extremely large coverage values
test_large_coverage_values() {
    print_test "Large coverage value handling"

    # Test with coverage > 100% (shouldn't happen, but let's be defensive)
    local test_values=("99.99" "100.00" "100.01")

    for value in "${test_values[@]}"; do
        # Check if bc can handle the comparison
        local result=$(echo "$value < 60" | bc -l)
        if [ "$result" == "0" ]; then
            pass "Large value $value handled correctly"
        else
            fail "Large value $value caused comparison error"
        fi
    done
}

# Test 8: Handle negative coverage values
test_negative_coverage_values() {
    print_test "Negative coverage value handling"

    # Test with negative values (shouldn't happen, but let's be defensive)
    local test_values=("-1.0" "0.0")

    for value in "${test_values[@]}"; do
        local result=$(echo "$value < 60" | bc -l)
        if [ "$result" == "1" ]; then
            pass "Value $value correctly identified as below threshold"
        else
            fail "Value $value comparison failed"
        fi
    done
}

# Test 9: Validate JSON output structure
test_json_structure() {
    print_test "JSON output structure validation"

    # Create a sample module report
    local temp_json="/tmp/module_test.json"
    cat > "$temp_json" << 'EOF'
[
  {
    "package": "test_package",
    "coverage": 65.5,
    "threshold": 60,
    "is_production": false,
    "status": "PASS"
  }
]
EOF

    # Validate JSON structure
    if jq empty "$temp_json" 2>/dev/null; then
        pass "JSON structure is valid"
    else
        fail "JSON structure is invalid"
    fi

    # Validate required fields
    local required_fields=("package" "coverage" "threshold" "is_production" "status")
    for field in "${required_fields[@]}"; do
        local has_field=$(jq -r ".[0] | has(\"$field\")" "$temp_json" 2>/dev/null)
        if [ "$has_field" == "true" ]; then
            pass "Required field '$field' present"
        else
            fail "Required field '$field' missing"
        fi
    done

    rm "$temp_json"
}

# Test 10: Validate bc availability and functionality
test_bc_availability() {
    print_test "bc calculator availability"

    if command -v bc &> /dev/null; then
        pass "bc is installed"
    else
        fail "bc is not installed (required for floating-point math)"
        return
    fi

    # Test bc -l (library mode) functionality
    local result=$(echo "scale=2; 10 / 3" | bc -l)
    if [[ "$result" =~ ^3\.3 ]]; then
        pass "bc -l works correctly for floating-point division"
    else
        fail "bc -l not working correctly (got: $result)"
    fi

    # Test bc comparison
    if (( $(echo "5.5 < 6.0" | bc -l) )); then
        pass "bc comparison works correctly"
    else
        fail "bc comparison not working"
    fi
}

# Test 11: Validate script error handling
test_error_handling() {
    print_test "Script error handling"

    # Test that script uses set -euo pipefail
    if grep -q "set -euo pipefail" scripts/enforce_coverage.sh; then
        pass "Script uses strict error handling (set -euo pipefail)"
    else
        fail "Script missing strict error handling"
    fi

    # Test for proper exit codes
    if grep -q "exit 1" scripts/enforce_coverage.sh; then
        pass "Script has explicit error exit codes"
    else
        fail "Script missing explicit error exit codes"
    fi
}

# Test 12: Validate output file creation
test_output_files() {
    print_test "Output file validation"

    local required_outputs=(
        "COVERAGE_JSON=\"coverage_report.json\""
        "COVERAGE_HTML=\"coverage_html\""
        "MODULE_REPORT=\"module_coverage.json\""
    )

    for output in "${required_outputs[@]}"; do
        if grep -q "$output" scripts/enforce_coverage.sh; then
            pass "Output file defined: $output"
        else
            fail "Output file not defined: $output"
        fi
    done
}

# Test 13: Validate color output
test_color_output() {
    print_test "Color output validation"

    local colors=("RED" "GREEN" "YELLOW" "BLUE" "NC")

    for color in "${colors[@]}"; do
        if grep -q "^$color=" scripts/enforce_coverage.sh; then
            pass "Color variable $color defined"
        else
            fail "Color variable $color not defined"
        fi
    done
}

# Test 14: Validate workspace member parsing
test_workspace_parsing() {
    print_test "Workspace member parsing"

    # Test that the script can parse workspace members
    if grep -q "cargo metadata --no-deps" scripts/enforce_coverage.sh; then
        pass "Script uses cargo metadata for workspace parsing"
    else
        fail "Script missing cargo metadata usage"
    fi

    # Test for proper jq parsing
    if grep -q "jq -r '.workspace_members" scripts/enforce_coverage.sh; then
        pass "Script uses jq to parse workspace members"
    else
        fail "Script missing jq workspace member parsing"
    fi
}

# Test 15: Validate timeout handling
test_timeout_handling() {
    print_test "Timeout handling"

    # Check for timeout parameter in coverage command
    if grep -q "timeout" scripts/enforce_coverage.sh; then
        pass "Script includes timeout handling"
    else
        fail "Script missing timeout handling"
    fi

    # Verify timeout value is reasonable (10 minutes = 600 seconds)
    if grep -q "timeout 600" scripts/enforce_coverage.sh; then
        pass "Timeout value is reasonable (600 seconds)"
    else
        fail "Timeout value not found or unreasonable"
    fi
}

# Main test execution
main() {
    echo -e "${BLUE}========================================${NC}"
    echo -e "${BLUE}  Coverage Edge Case Test Suite${NC}"
    echo -e "${BLUE}========================================${NC}"
    echo ""

    test_floating_point_comparison
    test_missing_llvm_cov
    test_empty_coverage_report
    test_malformed_json
    test_division_by_zero
    test_module_threshold_validation
    test_large_coverage_values
    test_negative_coverage_values
    test_json_structure
    test_bc_availability
    test_error_handling
    test_output_files
    test_color_output
    test_workspace_parsing
    test_timeout_handling

    echo ""
    echo -e "${BLUE}========================================${NC}"
    echo -e "${BLUE}  Edge Case Test Results${NC}"
    echo -e "${BLUE}========================================${NC}"
    echo -e "${GREEN}Passed: $TESTS_PASSED${NC}"
    echo -e "${RED}Failed: $TESTS_FAILED${NC}"

    if [ $TESTS_FAILED -eq 0 ]; then
        echo ""
        echo -e "${GREEN}✓ All edge case tests passed!${NC}"
        echo -e "${GREEN}Coverage enforcement is robust.${NC}"
        exit 0
    else
        echo ""
        echo -e "${RED}✗ Some edge case tests failed.${NC}"
        echo -e "${YELLOW}Please review the failures above.${NC}"
        exit 1
    fi
}

main "$@"