/*
 * Copyright (c) 2018-2019 Atmosphère-NX
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <cstdio>
#include <sys/stat.h>
#include <sys/types.h>
#include <atmosphere/version.h>

#include "fatal_config.hpp"
#include "fatal_task_error_report.hpp"

namespace sts::fatal::srv {

    namespace {

        /* Helpers. */
        void TryEnsureReportDirectories() {
            mkdir("sdmc:/atmosphere", S_IRWXU);
            mkdir("sdmc:/atmosphere/fatal_reports", S_IRWXU);
            mkdir("sdmc:/atmosphere/fatal_reports/dumps", S_IRWXU);
        }

        bool TryGetCurrentTimestamp(u64 *out) {
            /* Clear output. */
            *out = 0;

            /* Check if we have time service. */
            {
                bool has_time_service = false;
                if (R_FAILED(sm::HasService(&has_time_service, sm::ServiceName::Encode("time:s"))) || !has_time_service) {
                    return false;
                }
            }

            /* Try to get the current time. */
            {
                sm::ScopedServiceHolder<timeInitialize, timeExit> time_holder;
                return time_holder && R_SUCCEEDED(timeGetCurrentTime(TimeType_LocalSystemClock, out));
            }
        }

        /* Task definition. */
        class ErrorReportTask : public ITaskWithDefaultStack {
            private:
                void SaveReportToSdCard();
            public:
                virtual Result Run() override;
                virtual const char *GetName() const override {
                    return "WriteErrorReport";
                }
        };

        /* Task globals. */
        ErrorReportTask g_error_report_task;

        /* Task Implementation. */
        void ErrorReportTask::SaveReportToSdCard() {
            char file_path[FS_MAX_PATH];

            /* Try to Ensure path exists. */
            TryEnsureReportDirectories();

            /* Get a timestamp. */
            u64 timestamp;
            if (!TryGetCurrentTimestamp(&timestamp)) {
                timestamp = svcGetSystemTick();
            }

            /* Open report file. */
            snprintf(file_path, sizeof(file_path) - 1, "sdmc:/atmosphere/fatal_reports/%011lu_%016lx.log", timestamp, static_cast<u64>(this->context->title_id));
            FILE *f_report = fopen(file_path, "w");
            if (f_report != NULL) {
                ON_SCOPE_EXIT { fclose(f_report); };

                fprintf(f_report, "Atmosphère Fatal Report (v1.0):\n");
                fprintf(f_report, "Result:                          0x%X (2%03d-%04d)\n\n", this->context->error_code, R_MODULE(this->context->error_code), R_DESCRIPTION(this->context->error_code));
                fprintf(f_report, "Title ID:                        %016lx\n", static_cast<u64>(this->context->title_id));
                if (strlen(this->context->proc_name)) {
                    fprintf(f_report, "Process Name:                    %s\n", this->context->proc_name);
                }
                fprintf(f_report, u8"Firmware:                        %s (Atmosphère %u.%u.%u-%s)\n", GetFatalConfig().GetFirmwareVersion().display_version, ATMOSPHERE_RELEASE_VERSION, ams::GetGitRevision());

                if (this->context->cpu_ctx.architecture == CpuContext::Architecture_Aarch32) {
                    fprintf(f_report, "General Purpose Registers:\n");
                    for (size_t i = 0; i <= aarch32::RegisterName_PC; i++) {
                        if (this->context->cpu_ctx.aarch32_ctx.HasRegisterValue(static_cast<aarch32::RegisterName>(i))) {
                            fprintf(f_report,  "        %3s:                     %08x\n", aarch32::CpuContext::RegisterNameStrings[i], this->context->cpu_ctx.aarch32_ctx.r[i]);
                        }
                    }
                    fprintf(f_report, "Start Address:                   %08x\n", this->context->cpu_ctx.aarch32_ctx.base_address);
                    fprintf(f_report, "Stack Trace:\n");
                    for (unsigned int i = 0; i < this->context->cpu_ctx.aarch32_ctx.stack_trace_size; i++) {
                        fprintf(f_report, "        ReturnAddress[%02u]:       %08x\n", i, this->context->cpu_ctx.aarch32_ctx.stack_trace[i]);
                    }
                } else {
                    fprintf(f_report, "General Purpose Registers:\n");
                    for (size_t i = 0; i <= aarch64::RegisterName_PC; i++) {
                        if (this->context->cpu_ctx.aarch64_ctx.HasRegisterValue(static_cast<aarch64::RegisterName>(i))) {
                            fprintf(f_report,  "        %3s:                     %016lx\n", aarch64::CpuContext::RegisterNameStrings[i], this->context->cpu_ctx.aarch64_ctx.x[i]);
                        }
                    }
                    fprintf(f_report, "Start Address:                   %016lx\n", this->context->cpu_ctx.aarch64_ctx.base_address);
                    fprintf(f_report, "Stack Trace:\n");
                    for (unsigned int i = 0; i < this->context->cpu_ctx.aarch64_ctx.stack_trace_size; i++) {
                        fprintf(f_report, "        ReturnAddress[%02u]:       %016lx\n", i, this->context->cpu_ctx.aarch64_ctx.stack_trace[i]);
                    }
                }
            }

            if (this->context->stack_dump_size) {
                snprintf(file_path, sizeof(file_path) - 1, "sdmc:/atmosphere/fatal_reports/dumps/%011lu_%016lx.bin", timestamp, static_cast<u64>(this->context->title_id));
                FILE *f_stackdump = fopen(file_path, "wb");
                if (f_stackdump == NULL) { return; }
                ON_SCOPE_EXIT { fclose(f_stackdump); };

                fwrite(this->context->stack_dump, this->context->stack_dump_size, 1, f_stackdump);
                fflush(f_stackdump);
            }
        }

        Result ErrorReportTask::Run() {
            if (this->context->generate_error_report) {
                /* Here, Nintendo creates an error report with erpt. AMS will not do that. */
            }

            /* Save report to SD card. */
            if (!this->context->is_creport) {
                this->SaveReportToSdCard();
            }

            /* Signal we're done with our job. */
            eventFire(const_cast<Event *>(&this->context->erpt_event));

            return ResultSuccess;
        }

    }

    ITask *GetErrorReportTask(const ThrowContext *ctx) {
        g_error_report_task.Initialize(ctx);
        return &g_error_report_task;
    }

}