if(NOT DEFINED ENV_FILE)
    message(FATAL_ERROR "ENV_FILE is not set")
endif()

if(NOT DEFINED OUT_HEADER)
    message(FATAL_ERROR "OUT_HEADER is not set")
endif()

if(NOT EXISTS "${ENV_FILE}")
    message(FATAL_ERROR ".env file not found: ${ENV_FILE}")
endif()

file(STRINGS "${ENV_FILE}" ENV_LINES)

set(HEADER_CONTENT "#pragma once\n#include \"dusk.h\"\n\n")

foreach(line IN LISTS ENV_LINES)
  # Trim whitespace
  string(REGEX REPLACE "^[ \t]*" "" line "${line}")
  string(REGEX REPLACE "[ \t]*$" "" line "${line}")

  # Skip comments and empty lines (allow whitespace before # or ;)
  if(line STREQUAL "" OR line MATCHES "^[ \t]*[#;]")
    continue()
  endif()

  # Expect KEY=VALUE
  if(NOT line MATCHES "^[A-Za-z_][A-Za-z0-9_]*=")
    message(WARNING "Skipping invalid line in ${ENV_FILE}: '${line}'")
    continue()
  endif()

  # Extract key
  string(REGEX MATCH "^[A-Za-z_][A-Za-z0-9_]*" KEY "${line}")
  string(LENGTH "${KEY}" key_len)

  # Extract value
  string(SUBSTRING "${line}" ${key_len} -1 rest)
  string(REGEX REPLACE "^[ \t]*=[ \t]*" "" RAW_VALUE "${rest}")

  # Lowercase copy for boolean detection
  string(TOLOWER "${RAW_VALUE}" VALUE_LC)
  set(VALUE "${RAW_VALUE}")

  # Determine type and format accordingly
  if(VALUE_LC STREQUAL "true")
    set(HEADER_CONTENT "${HEADER_CONTENT}#define ${KEY} true\n")

  elseif(VALUE_LC STREQUAL "false")
    set(HEADER_CONTENT "${HEADER_CONTENT}#define ${KEY} false\n")

  elseif(VALUE MATCHES "^[+-]?[0-9]+$")
    # Integer
    set(HEADER_CONTENT "${HEADER_CONTENT}#define ${KEY} ${VALUE}\n")

  elseif(VALUE MATCHES "^[+-]?[0-9]*\\.[0-9]+$")
    # Float → append "f"
    set(HEADER_CONTENT "${HEADER_CONTENT}#define ${KEY} ${VALUE}f\n")

  else()
    # String → escape for C literal
    string(REPLACE "\\" "\\\\" VALUE_ESC "${VALUE}")
    string(REPLACE "\"" "\\\"" VALUE_ESC "${VALUE_ESC}")
    set(HEADER_CONTENT "${HEADER_CONTENT}#define ${KEY} \"${VALUE_ESC}\"\n")
  endif()
endforeach()

file(WRITE "${OUT_HEADER}" "${HEADER_CONTENT}")
message(STATUS "Generated header: ${OUT_HEADER}")