#!/bin/bash

# dedupe_list() is a helper function to dedupe a list of items separated by a given separator
# eg dedupe_list ":" "a:b:a:c" will return "a:b:c", or dedupe_list ":" "$PATH" will return a deduped $PATH
# the seperator you pass is used to split the existing list, and reinserted in the same order
dedupe_list() {
    local separator="$1"
    # Use awk to preserve order while deduping
    echo "$2" | tr "$separator" '\n' | awk '!seen[$0]++ && NF' | tr '\n' "$separator"
}

test_dedupe_list() {
    local failed=0
    local total=0

    # Helper function to run a test case
    run_test() {
        local test_name="$1"
        local separator="$2"
        local input="$3"
        local expected="$4"
        local result

        ((total++))
        result=$(dedupe_list "$separator" "$input")
        
        if [ "$result" = "$expected" ]; then
            echo "✓ PASS: $test_name"
        else
            echo "✗ FAIL: $test_name"
            echo "  Input   : $input"
            echo "  Expected: $expected"
            echo "  Got     : $result"
            ((failed++))
        fi
    }

    # Test PATH-style cases (colon separator)
    run_test "Basic PATH dedup" ":" \
        "/usr/bin:/bin:/usr/bin:/sbin" \
        "/usr/bin:/bin:/sbin:"

    run_test "Empty PATH segments" ":" \
        "/usr/bin::/bin::/usr/bin:" \
        "/usr/bin:/bin:"

    run_test "Single PATH entry" ":" \
        "/usr/bin" \
        "/usr/bin:"

    run_test "No duplicates" ":" \
        "/usr/bin:/bin:/sbin" \
        "/usr/bin:/bin:/sbin:"

    run_test "Complex PATH" ":" \
        "/usr/local/bin:/usr/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin" \
        "/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:"

    # Test space-separated variables
    run_test "Basic space-separated" " " \
        "foo bar foo baz" \
        "foo bar baz "

    run_test "Multiple spaces" " " \
        "foo   bar   foo   baz" \
        "foo bar baz "

    run_test "Single word" " " \
        "foo" \
        "foo "

    # Test with empty input
    run_test "Empty input" ":" \
        "" \
        ""

    # Test with special characters
    run_test "Special chars" ":" \
        "/path/with spaces:/path/with spaces:/path/with:colons" \
        "/path/with spaces:/path/with:colons:"

    # Summary
    echo "-------------------"
    echo "Tests completed: $total"
    echo "Failed: $failed"
    echo "Passed: $((total - failed))"
    
    return $failed
}

# Run the tests
test_dedupe_list