#include <assert.h>
#include <ast/ast.h>
#include <codegen/backend.h>
#include <llvm-c/Core.h>
#include <llvm-c/TargetMachine.h>
#include <llvm/backend.h>
#include <llvm/parser.h>
#include <mem/cache.h>
#include <sys/log.h>

Target create_native_target() {
    DEBUG("creating native target...");
    Target target;

    target.name.str        = "tmp";
    target.name.allocation = NONE;

    target.triple.str        = LLVMGetDefaultTargetTriple();
    target.triple.allocation = LLVM;
    assert(target.triple.str != NULL);

    target.cpu.str        = LLVMGetHostCPUName();
    target.cpu.allocation = LLVM;
    assert(target.cpu.str != NULL);

    target.features.str        = LLVMGetHostCPUFeatures();
    target.features.allocation = LLVM;
    assert(target.features.str != NULL);

    target.opt   = LLVMCodeGenLevelNone;
    target.reloc = LLVMRelocDefault;
    target.model = LLVMCodeModelDefault;

    return target;
}

LLVMCodeGenOptLevel llvm_opt_from_int(int level) {
    switch (level) {
        case 1:
            return LLVMCodeGenLevelLess;
        case 2:
            return LLVMCodeGenLevelDefault;
        case 3:
            return LLVMCodeGenLevelAggressive;
        default:
            break;
    }
    PANIC("invalid code generation optimization level: %d", level);
}

static char* create_target_output_name(const TargetConfig* config) {
    char* prefix = "";
    if (config->mode == Library) {
        prefix = "lib";
    }

    char* name        = g_strjoin("", prefix, config->name, NULL);
    char* cached_name = mem_strdup(MemoryNamespaceLlvm, name);
    g_free(name);

    return cached_name;
}

Target create_target_from_config(const TargetConfig* config) {
    DEBUG("Building target from configuration");

    Target target = create_native_target();

    target.name.str        = create_target_output_name(config);
    target.name.allocation = NONE; // freed later by compiler

    target.opt = llvm_opt_from_int(config->optimization_level);

    INFO("Configured target: %s/%d: (%s) on %s { %s }", target.name.str,
         target.opt, target.triple.str, target.cpu.str, target.features.str);

    return target;
}

static void delete_string(String string) {
    DEBUG("deleting string...");
    switch (string.allocation) {
        case LLVM:
            LLVMDisposeMessage(string.str);
            break;
        case LIBC:
            free(string.str);
            break;
        case NONE:
            break;
    }
}

void delete_target(Target target) {
    delete_string(target.name);
    delete_string(target.cpu);
    delete_string(target.features);
    delete_string(target.triple);
}

typedef enum LLVMBackendError_t { UnresolvedImport } LLVMBackendError;

static BackendError llvm_backend_codegen(const Module* unit,
                                         const TargetConfig* target) {
    return parse_module(unit, target);
}

static BackendError llvm_backend_codegen_init(void) {
    return new_backend_error(Success);
}

static BackendError llvm_backend_codegen_deinit(void) {
    return new_backend_error(Success);
}

void llvm_backend_init() {
    BackendError err =
      set_backend(&llvm_backend_codegen_init, &llvm_backend_codegen_deinit,
                  &llvm_backend_codegen, "LLVM");

    if (err.kind != Success) {
        PANIC("unable to init llvm backend: %ld", err);
    }
}