########################################################################################################################
# @file FindXilinx.cmake
# @author Andrew D. Zonenberg
# @brief Xilinx ISE toolchain CMake module
########################################################################################################################

########################################################################################################################
# Autodetect Xilinx paths (very hacky for now)

# Find /opt/Xilinx or similar
find_file(XILINX_PARENT NAMES Xilinx PATHS /opt)
if(XILINX_PARENT STREQUAL "XILINX_PARENT-NOTFOUND")
    message(FATAL_ERROR "No Xilinx toolchain installation found")
endif()

# Find /opt/Xilinx/VERSION
# TODO: Figure out a better way of doing this
find_file(XILINX NAMES 14.3 PATHS ${XILINX_PARENT})
if(XILINX STREQUAL "XILINX-NOTFOUND")
    message(FATAL_ERROR "No ISE 14.3 installation found")
endif()
message(STATUS "Found Xilinx toolchain... ${XILINX}")

# Set current OS architecture (TODO: autodetect)
set(XILINX_ARCH lin64)

# Find fuse
find_file(FUSE NAMES fuse PATHS "${XILINX}/ISE_DS/ISE/bin/${XILINX_ARCH}/")
if(FUSE STREQUAL "FUSE-NOTFOUND")
    message(FATAL_ERROR "No Xilinx fuse installation found")
endif()
message(STATUS "Found Xilinx fuse... ${FUSE}")

########################################################################################################################
# Argument parsing helper

macro(xilinx_parse_args _top_level _sources)
    set(${_top_level} FALSE)
    set(${_sources})
    set(_found_sources FALSE)
    set(_found_top_level FALSE)
    foreach(arg ${ARGN})
        if(${arg} STREQUAL "TOP_LEVEL")
            set(_found_top_level TRUE)
        elseif(${arg} STREQUAL "SOURCES")
            set(_found_sources TRUE)
        elseif(${_found_sources})
            list(APPEND ${_sources} ${arg})
        elseif(${_found_top_level})
            if(${_top_level})
                message(FATAL_ERROR "Multiple top-level files specified in xilinx_parse_args")
            else()
                set(${_top_level} ${arg})
            endif()
        else()
            message(FATAL_ERROR "Unrecognized command ${arg} in xilinx_parse_args")
        endif()
    endforeach()
endmacro()

########################################################################################################################
# ISim executable generation

function(add_isim_executable OUTPUT_FILE )

    # Parse args
    xilinx_parse_args(TOP_LEVEL SOURCES ${ARGN})

    # Get base name without extension of the top-level module
    get_filename_component(TOPLEVEL_BASENAME ${TOP_LEVEL} NAME_WE )

    # Write the .prj file
    set(PRJ_FILE "${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_FILE}.prj")
    file(WRITE ${PRJ_FILE} "verilog work \"${TOP_LEVEL}\"\n")
    foreach(f ${SOURCES})
        file(APPEND ${PRJ_FILE} "verilog work \"${f}\"\n")
    endforeach()
    file(APPEND ${PRJ_FILE} "verilog work \"${XILINX}/ISE_DS/ISE/verilog/src/glbl.v\"\n")

    # Main compile rule
    # TODO: tweak this
    add_custom_target(
        ${OUTPUT_FILE} ALL
        COMMAND ${FUSE} ${FUSE_FLAGS} -o ${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_FILE} -prj ${PRJ_FILE}
                work.${TOPLEVEL_BASENAME} work.glbl > ${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_FILE}_build.log
                2> ${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_FILE}_err.log
        DEPENDS ${SOURCES} ${TOP_LEVEL}
        COMMENT "Building ISim executable ${OUTPUT_FILE}..."
    )

    # Write the tcl script
    set(TCL_FILE "${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_FILE}.tcl")
    file(WRITE ${TCL_FILE} "onerror {resume}\n")
    file(APPEND ${TCL_FILE} "wave add /\n")
    file(APPEND ${TCL_FILE} "run 1000 ns;\n")
    file(APPEND ${TCL_FILE} "exit;\n")

    # Write the run-test wrapper script
    set(TEST_WRAPPER "${CMAKE_CURRENT_BINARY_DIR}/run${OUTPUT_FILE}.sh")
    file(WRITE ${TEST_WRAPPER} "#!/bin/bash\n")
    file(APPEND ${TEST_WRAPPER} "cd ${CMAKE_CURRENT_BINARY_DIR}\n")
    file(APPEND ${TEST_WRAPPER} "source ${XILINX}/ISE_DS/settings64.sh\n")
    file(APPEND ${TEST_WRAPPER} "./${OUTPUT_FILE} -tclbatch ${TCL_FILE} -intstyle silent -vcdfile ${OUTPUT_FILE}.vcd -vcdunit ps || exit 1\n")
    file(APPEND ${TEST_WRAPPER} "cat isim.log | grep -q FAIL\n")
    file(APPEND ${TEST_WRAPPER} "if [ \"$?\" != \"1\" ]; then\n")
    file(APPEND ${TEST_WRAPPER} "    exit 1;\n")
    file(APPEND ${TEST_WRAPPER} "fi\n")
    add_custom_command(TARGET ${OUTPUT_FILE} POST_BUILD COMMAND chmod +x ${TEST_WRAPPER})

endfunction()

########################################################################################################################
# Test generation
#
# Usage:
# add_isim_test(NandGate
#   TOP_LEVEL
#       ${CMAKE_CURRENT_SOURCE_DIR}/testNandGate.v
#   SOURCES
#       ${CMAKE_SOURCE_DIR}/hdl/NandGate.v
#   )

function(add_isim_test TEST_NAME)

    # Parse args
    xilinx_parse_args(TOP_LEVEL SOURCES ${ARGN})

    # Add the sim executable
    add_isim_executable(test${TEST_NAME}
        TOP_LEVEL
            ${TOP_LEVEL}
        SOURCES
            ${SOURCES}
        )

    add_test(${TEST_NAME}
        "${CMAKE_CURRENT_BINARY_DIR}/runtest${TEST_NAME}.sh")
    set_property(TEST ${TEST_NAME} APPEND PROPERTY DEPENDS test${TEST_NAME})


endfunction()