# Code Generation Module
# Asset packing, timeline compilation, and music compilation

# =============================================================================
# Helper Functions
# =============================================================================

# Helper to parse asset list and extract individual file paths
function(parse_asset_list INPUT_TXT OUT_FILE_LIST)
    set(ASSET_FILES "")
    if(EXISTS ${INPUT_TXT})
        # Get directory of INPUT_TXT for relative path resolution
        get_filename_component(INPUT_DIR ${INPUT_TXT} DIRECTORY)

        file(STRINGS ${INPUT_TXT} LINES)
        foreach(LINE ${LINES})
            # Skip comments and empty lines
            string(STRIP "${LINE}" LINE)
            if(NOT LINE MATCHES "^#" AND NOT LINE STREQUAL "")
                # Extract filename (third field: ASSET_NAME, COMPRESSION, FILENAME, DESC)
                string(REGEX REPLACE "^[^,]+,[^,]+,[ ]*([^,]+).*" "\\1" FILENAME "${LINE}")
                string(STRIP "${FILENAME}" FILENAME)

                # Use workspace-relative path
                set(FULL_PATH "${INPUT_DIR}/${FILENAME}")

                if(EXISTS ${FULL_PATH})
                    list(APPEND ASSET_FILES ${FULL_PATH})
                endif()
            endif()
        endforeach()
    endif()
    set(${OUT_FILE_LIST} ${ASSET_FILES} PARENT_SCOPE)
endfunction()

# Pack assets for demo (output to src/generated/)
function(pack_assets NAME INPUT_TXT HEADER_VAR DATA_CC_VAR TARGET_NAME)
    set(OUT_H ${CMAKE_CURRENT_SOURCE_DIR}/src/generated/${NAME}.h)
    set(OUT_CC ${CMAKE_CURRENT_SOURCE_DIR}/src/generated/${NAME}_data.cc)

    # Parse asset list to get individual file dependencies
    parse_asset_list(${INPUT_TXT} ASSET_FILE_DEPS)

    add_custom_command(
        OUTPUT ${OUT_H} ${OUT_CC}
        COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_SOURCE_DIR}/src/generated
        COMMAND ${ASSET_PACKER_CMD} ${INPUT_TXT} ${OUT_H} ${OUT_CC}
        DEPENDS ${ASSET_PACKER_DEPENDS} ${INPUT_TXT} ${ASSET_FILE_DEPS}
        COMMENT "Generating assets for ${NAME}..."
    )
    set(${HEADER_VAR} ${OUT_H} PARENT_SCOPE)
    set(${DATA_CC_VAR} ${OUT_CC} PARENT_SCOPE)
    add_custom_target(${TARGET_NAME} DEPENDS ${OUT_H} ${OUT_CC})
endfunction()

# Pack assets by category (filters by filename pattern)
function(pack_assets_category NAME PATTERN INPUT_TXT HEADER_VAR DATA_CC_VAR TARGET_NAME)
    set(OUT_H ${CMAKE_CURRENT_SOURCE_DIR}/src/generated/${NAME}.h)
    set(OUT_CC ${CMAKE_CURRENT_SOURCE_DIR}/src/generated/${NAME}_data.cc)

    # Get directory of INPUT_TXT for relative path resolution
    get_filename_component(INPUT_DIR ${INPUT_TXT} DIRECTORY)
    get_filename_component(INPUT_NAME ${INPUT_TXT} NAME_WE)
    set(FILTERED_TXT ${INPUT_DIR}/${INPUT_NAME}_${NAME}.txt)

    # Create filtered asset list
    file(STRINGS ${INPUT_TXT} ALL_LINES)
    set(FILTERED_LINES "")
    foreach(LINE ${ALL_LINES})
        string(STRIP "${LINE}" LINE)
        if(LINE MATCHES "^#" OR LINE STREQUAL "")
            list(APPEND FILTERED_LINES "${LINE}")
        else()
            string(REGEX REPLACE "^[^,]+,[^,]+,[ ]*([^,]+).*" "\\1" FILENAME "${LINE}")
            if(FILENAME MATCHES "${PATTERN}")
                list(APPEND FILTERED_LINES "${LINE}")
            endif()
        endif()
    endforeach()
    string(REPLACE ";" "\n" FILTERED_CONTENT "${FILTERED_LINES}")
    file(WRITE ${FILTERED_TXT} "${FILTERED_CONTENT}\n")

    # Parse filtered list for dependencies (now in same directory as INPUT_TXT)
    parse_asset_list(${FILTERED_TXT} ASSET_FILE_DEPS)

    add_custom_command(
        OUTPUT ${OUT_H} ${OUT_CC}
        COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_SOURCE_DIR}/src/generated
        COMMAND ${ASSET_PACKER_CMD} ${FILTERED_TXT} ${OUT_H} ${OUT_CC}
        DEPENDS ${ASSET_PACKER_DEPENDS} ${INPUT_TXT} ${ASSET_FILE_DEPS}
        COMMENT "Generating ${NAME} assets..."
    )
    set(${HEADER_VAR} ${OUT_H} PARENT_SCOPE)
    set(${DATA_CC_VAR} ${OUT_CC} PARENT_SCOPE)
    add_custom_target(${TARGET_NAME} DEPENDS ${OUT_H} ${OUT_CC})
endfunction()

# Pack test assets (output to build/src/generated_test/)
function(pack_test_assets NAME INPUT_TXT HEADER_VAR DATA_CC_VAR TARGET_NAME)
    set(OUT_H ${CMAKE_CURRENT_BINARY_DIR}/src/generated_test/${NAME}.h)
    set(OUT_CC ${CMAKE_CURRENT_BINARY_DIR}/src/generated_test/${NAME}_data.cc)

    # Parse asset list to get individual file dependencies
    parse_asset_list(${INPUT_TXT} ASSET_FILE_DEPS)

    add_custom_command(
        OUTPUT ${OUT_H} ${OUT_CC}
        COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/src/generated_test
        COMMAND ${ASSET_PACKER_CMD} ${INPUT_TXT} ${OUT_H} ${OUT_CC}
        DEPENDS ${ASSET_PACKER_DEPENDS} ${INPUT_TXT} ${ASSET_FILE_DEPS}
        COMMENT "Generating assets for test ${NAME}..."
    )
    set(${HEADER_VAR} ${OUT_H} PARENT_SCOPE)
    set(${DATA_CC_VAR} ${OUT_CC} PARENT_SCOPE)
    add_custom_target(${TARGET_NAME} DEPENDS ${OUT_H} ${OUT_CC})
endfunction()

# =============================================================================
# Generation Targets
# =============================================================================

# Timeline compilation
set(DEMO_SEQ_PATH ${WORKSPACE_TIMELINE})
set(GENERATED_TIMELINE_CC ${CMAKE_CURRENT_SOURCE_DIR}/src/generated/timeline.cc)
add_custom_command(
    OUTPUT ${GENERATED_TIMELINE_CC}
    COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_SOURCE_DIR}/src/generated
    COMMAND ${SEQ_COMPILER_CMD} ${DEMO_SEQ_PATH} ${GENERATED_TIMELINE_CC}
    DEPENDS ${SEQ_COMPILER_DEPENDS} ${DEMO_SEQ_PATH}
            src/gpu/demo_effects.h
    COMMENT "Compiling demo sequence from workspace ${DEMO_WORKSPACE}..."
)
add_custom_target(generate_timeline ALL DEPENDS ${GENERATED_TIMELINE_CC})

# Music compilation
set(TRACKER_MUSIC_PATH ${WORKSPACE_MUSIC})
set(GENERATED_MUSIC_DATA_CC ${CMAKE_CURRENT_SOURCE_DIR}/src/generated/music_data.cc)
add_custom_command(
    OUTPUT ${GENERATED_MUSIC_DATA_CC}
    COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_SOURCE_DIR}/src/generated
    COMMAND ${TRACKER_COMPILER_FINAL_CMD} ${TRACKER_MUSIC_PATH} ${GENERATED_MUSIC_DATA_CC}
    DEPENDS ${TRACKER_COMPILER_FINAL_DEPENDS} ${TRACKER_MUSIC_PATH} tracker_compiler_host
    COMMENT "Compiling tracker music from workspace ${DEMO_WORKSPACE}..."
)
add_custom_target(generate_tracker_music ALL DEPENDS ${GENERATED_MUSIC_DATA_CC})

# Asset packing (split by category for granular rebuild tracking)
# Generate filtered asset files per category
get_filename_component(ASSETS_DIR ${WORKSPACE_ASSETS} DIRECTORY)
set(FILTERED_SHADERS ${ASSETS_DIR}/assets_filtered_shaders.txt)
set(FILTERED_AUDIO ${ASSETS_DIR}/assets_filtered_audio.txt)
set(FILTERED_MODELS ${ASSETS_DIR}/assets_filtered_models.txt)
set(FILTERED_DATA ${ASSETS_DIR}/assets_filtered_data.txt)

# Filter assets by category at configure time
file(STRINGS ${WORKSPACE_ASSETS} ALL_ASSET_LINES)
set(SHADERS_LINES "")
set(AUDIO_LINES "")
set(MODELS_LINES "")
set(DATA_LINES "")

foreach(LINE ${ALL_ASSET_LINES})
    string(STRIP "${LINE}" LINE)
    if(LINE MATCHES "^#" OR LINE STREQUAL "")
        list(APPEND SHADERS_LINES "${LINE}")
        list(APPEND AUDIO_LINES "${LINE}")
        list(APPEND MODELS_LINES "${LINE}")
        list(APPEND DATA_LINES "${LINE}")
    else()
        string(REGEX REPLACE "^[^,]+,[^,]+,[ ]*([^,]+).*" "\\1" FILENAME "${LINE}")
        if(FILENAME MATCHES "\\.wgsl$")
            list(APPEND SHADERS_LINES "${LINE}")
        elseif(FILENAME MATCHES "\\.(spec|track)$")
            list(APPEND AUDIO_LINES "${LINE}")
        elseif(FILENAME MATCHES "\\.obj$")
            list(APPEND MODELS_LINES "${LINE}")
        elseif(FILENAME MATCHES "\\.(bin|png)$" OR FILENAME MATCHES "PROC\\(")
            list(APPEND DATA_LINES "${LINE}")
        endif()
    endif()
endforeach()

string(REPLACE ";" "\n" SHADERS_CONTENT "${SHADERS_LINES}")
string(REPLACE ";" "\n" AUDIO_CONTENT "${AUDIO_LINES}")
string(REPLACE ";" "\n" MODELS_CONTENT "${MODELS_LINES}")
string(REPLACE ";" "\n" DATA_CONTENT "${DATA_LINES}")

file(WRITE ${FILTERED_SHADERS} "${SHADERS_CONTENT}\n")
file(WRITE ${FILTERED_AUDIO} "${AUDIO_CONTENT}\n")
file(WRITE ${FILTERED_MODELS} "${MODELS_CONTENT}\n")
file(WRITE ${FILTERED_DATA} "${DATA_CONTENT}\n")

# Parse dependencies per category
parse_asset_list(${FILTERED_SHADERS} SHADERS_DEPS)
parse_asset_list(${FILTERED_AUDIO} AUDIO_DEPS)
parse_asset_list(${FILTERED_MODELS} MODELS_DEPS)
parse_asset_list(${FILTERED_DATA} DATA_DEPS)

# Single unified output (avoids duplicate symbols)
set(GEN_DEMO_H ${CMAKE_CURRENT_SOURCE_DIR}/src/generated/assets.h)
set(GEN_DEMO_CC ${CMAKE_CURRENT_SOURCE_DIR}/src/generated/assets_data.cc)

# Category-specific targets for granular rebuilds
add_custom_command(
    OUTPUT ${GEN_DEMO_H}.shaders_stamp
    COMMAND ${CMAKE_COMMAND} -E touch ${GEN_DEMO_H}.shaders_stamp
    DEPENDS ${ASSET_PACKER_DEPENDS} ${WORKSPACE_ASSETS} ${SHADERS_DEPS}
    COMMENT "Checking shader assets..."
)
add_custom_target(generate_demo_shaders DEPENDS ${GEN_DEMO_H}.shaders_stamp)

add_custom_command(
    OUTPUT ${GEN_DEMO_H}.audio_stamp
    COMMAND ${CMAKE_COMMAND} -E touch ${GEN_DEMO_H}.audio_stamp
    DEPENDS ${ASSET_PACKER_DEPENDS} ${WORKSPACE_ASSETS} ${AUDIO_DEPS}
    COMMENT "Checking audio assets..."
)
add_custom_target(generate_demo_audio DEPENDS ${GEN_DEMO_H}.audio_stamp)

add_custom_command(
    OUTPUT ${GEN_DEMO_H}.models_stamp
    COMMAND ${CMAKE_COMMAND} -E touch ${GEN_DEMO_H}.models_stamp
    DEPENDS ${ASSET_PACKER_DEPENDS} ${WORKSPACE_ASSETS} ${MODELS_DEPS}
    COMMENT "Checking model assets..."
)
add_custom_target(generate_demo_models DEPENDS ${GEN_DEMO_H}.models_stamp)

add_custom_command(
    OUTPUT ${GEN_DEMO_H}.data_stamp
    COMMAND ${CMAKE_COMMAND} -E touch ${GEN_DEMO_H}.data_stamp
    DEPENDS ${ASSET_PACKER_DEPENDS} ${WORKSPACE_ASSETS} ${DATA_DEPS}
    COMMENT "Checking data assets..."
)
add_custom_target(generate_demo_data DEPENDS ${GEN_DEMO_H}.data_stamp)

# Unified asset generation (triggered when any category changes)
add_custom_command(
    OUTPUT ${GEN_DEMO_H} ${GEN_DEMO_CC}
    COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_SOURCE_DIR}/src/generated
    COMMAND ${ASSET_PACKER_CMD} ${WORKSPACE_ASSETS} ${GEN_DEMO_H} ${GEN_DEMO_CC}
    DEPENDS ${ASSET_PACKER_DEPENDS} ${WORKSPACE_ASSETS}
            ${GEN_DEMO_H}.shaders_stamp
            ${GEN_DEMO_H}.audio_stamp
            ${GEN_DEMO_H}.models_stamp
            ${GEN_DEMO_H}.data_stamp
    COMMENT "Generating unified assets..."
)

# Combined target for compatibility
add_custom_target(generate_demo_assets DEPENDS ${GEN_DEMO_H} ${GEN_DEMO_CC})

# Test assets (unchanged)
pack_test_assets(test_assets ${CMAKE_CURRENT_SOURCE_DIR}/workspaces/test/assets.txt GEN_TEST_H GEN_TEST_CC generate_test_assets)

# Mark generated files so CMake always checks if they need rebuilding
set_source_files_properties(${GEN_DEMO_H} ${GEN_DEMO_CC} PROPERTIES GENERATED TRUE)
set_source_files_properties(${GEN_TEST_H} ${GEN_TEST_CC} PROPERTIES GENERATED TRUE)
set_source_files_properties(${GENERATED_TIMELINE_CC} PROPERTIES GENERATED TRUE)
set_source_files_properties(${GENERATED_MUSIC_DATA_CC} PROPERTIES GENERATED TRUE)