#include <iostream>
#include <filesystem>
#include <fstream>

#include <iomanip>
#include <algorithm>
#include <iostream>

#include <catch2/catch.hpp>

#include "daggy/Utilities.hpp"
#include "daggy/Serialization.hpp"
#include "daggy/executors/task/ForkingTaskExecutor.hpp"
#include "daggy/loggers/dag_run/OStreamLogger.hpp"

namespace fs = std::filesystem;

TEST_CASE("String Utilities", "[utilities_string]") {
    std::string test = "/this/is/{{A}}/test/{{A}}";
    auto res = daggy::globalSub(test, "{{A}}", "hello");
    REQUIRE(res == "/this/is/hello/test/hello");
}

TEST_CASE("Parameter Expansion", "[utilities_parameter_expansion]") {
    SECTION("Basic expansion") {
        std::string testParams{R"({"DATE": ["2021-05-06", "2021-05-07" ], "SOURCE": "name", "TYPE": ["a", "b", "c"]})"};
        auto params = daggy::parametersFromJSON(testParams);
        std::vector<std::string> cmd{"/usr/bin/echo", "{{DATE}}", "{{SOURCE}}", "{{TYPE}}"};
        auto allCommands = daggy::expandCommands(cmd, params);

        REQUIRE(allCommands.size() == 6);
    }

    SECTION("Skip over unused parameters") {
        std::string testParams{R"({"DATE": ["2021-05-06", "2021-05-07" ], "SOURCE": "name", "TYPE": ["a", "b", "c"]})"};
        auto params = daggy::parametersFromJSON(testParams);
        std::vector<std::string> cmd{"/usr/bin/echo", "{{DATE}}", "{{SOURCE}}"};
        auto allCommands = daggy::expandCommands(cmd, params);

        // TYPE isn't used, so it's just |DATE| * |SOURCE|
        REQUIRE(allCommands.size() == 2);
    }

    SECTION("Expand within a command part") {
        std::string testParams{
                R"({"DATE": ["2021-05-06", "2021-05-07" ], "SOURCE": ["A", "B"], "TYPE": ["a", "b", "c"]})"};
        auto params = daggy::parametersFromJSON(testParams);
        std::vector<std::string> cmd{"/usr/bin/touch", "{{DATE}}_{{SOURCE}}"};
        auto result = daggy::expandCommands(cmd, params);

        // TYPE isn't used, so it's just |DATE| * |SOURCE|
        REQUIRE(result.size() == 4);


    }
}

TEST_CASE("DAG Runner", "[utilities_dag_runner]") {
    daggy::executors::task::ForkingTaskExecutor ex(10);
    std::stringstream ss;
    daggy::loggers::dag_run::OStreamLogger logger(ss);

    SECTION("Simple execution") {
        std::string prefix = "asdlk_";
        std::string taskJSON = R"({"A": {"command": ["/usr/bin/touch", ")"
                               + prefix + R"(A"], "children": ["C"]}, "B": {"command": ["/usr/bin/touch", ")"
                               + prefix + R"(B"], "children": ["C"]}, "C": {"command": ["/usr/bin/touch", ")"
                               + prefix + R"(C"]}})";
        auto tasks = daggy::tasksFromJSON(taskJSON);
        auto dag = daggy::buildDAGFromTasks(tasks);

        auto runID = logger.startDAGRun("test_run", tasks);
        auto endDAG = daggy::runDAG(runID, ex, logger, dag);

        REQUIRE(endDAG.allVisited());

        std::vector<std::string> letters{"A", "B", "C"};
        for (const auto &letter: letters) {
            fs::path file{prefix + letter};
            REQUIRE(fs::exists(file));
            fs::remove(file);
        }

        // Get the DAG Run Attempts
        auto record = logger.getDAGRun(runID);
        for (const auto &[_, attempts]: record.taskAttempts) {
            REQUIRE(attempts.size() == 1);
            REQUIRE(attempts.front().rc == 0);
        }
    }

    SECTION("Recovery from Error") {
        auto cleanup = []() {
            // Cleanup
            std::vector<fs::path> paths{"rec_error_A", "noexist"};
            for (const auto &pth: paths) {
                if (fs::exists(pth)) fs::remove_all(pth);
            }
        };

        cleanup();

        std::string goodPrefix = "rec_error_";
        std::string badPrefix = "noexist/rec_error_";
        std::string taskJSON = R"({"A": {"command": ["/usr/bin/touch", ")"
                               + goodPrefix +
                               R"(A"], "children": ["C"]}, "B": {"command": ["/usr/bin/touch", ")"
                               + badPrefix + R"(B"], "children": ["C"]}, "C": {"command": ["/usr/bin/touch", ")"
                               + badPrefix + R"(C"]}})";
        auto tasks = daggy::tasksFromJSON(taskJSON);
        auto dag = daggy::buildDAGFromTasks(tasks);

        auto runID = logger.startDAGRun("test_run", tasks);

        auto tryDAG = daggy::runDAG(runID, ex, logger, dag);

        REQUIRE(!tryDAG.allVisited());

        // Create the missing dir, then continue to run the DAG
        fs::create_directory("noexist");
        tryDAG.resetRunning();
        auto endDAG = daggy::runDAG(runID, ex, logger, tryDAG);

        REQUIRE(endDAG.allVisited());

        // Get the DAG Run Attempts
        auto record = logger.getDAGRun(runID);
        REQUIRE(record.taskAttempts["A"].size() == 1); // A ran fine
        REQUIRE(record.taskAttempts["B"].size() == 2); // B errored and had to be retried
        REQUIRE(record.taskAttempts["C"].size() == 1); // C wasn't run because B errored

        cleanup();
    }

    SECTION("Generator tasks") {
        std::string testParams{R"({"DATE": ["2021-05-06", "2021-05-07" ]})"};
        auto params = daggy::parametersFromJSON(testParams);

        std::string generatorOutput = R"({"B": {"command": ["/usr/bin/echo", "{{DATE}}"], "children": ["C"]}})";
        std::stringstream jsonTasks;

        jsonTasks << R"({ "A": { "command": [ "/usr/bin/echo", )" << std::quoted(generatorOutput)
                  << R"(], "children": ["C"], "isGenerator": true},)"
                  << R"("C": { "command": [ "/usr/bin/echo", "hello!"] } })";

        auto tasks = daggy::tasksFromJSON(jsonTasks.str());
        auto dag = daggy::buildDAGFromTasks(tasks);
        REQUIRE(dag.size() == 2);

        auto runID = logger.startDAGRun("generator_run", tasks);
        auto finalDAG = daggy::runDAG(runID, ex, logger, dag, params);

        REQUIRE(finalDAG.size() == 4);

        // Check the logger
        auto record = logger.getDAGRun(runID);

        REQUIRE(record.tasks.size() == 4);
        REQUIRE(record.taskRunStates.size() == 4);
        for (const auto & [taskName, attempts] : record.taskAttempts) {
            REQUIRE(attempts.size() == 1);
            REQUIRE(attempts.back().rc == 0);
        }

        // Ensure that children were updated properly
        REQUIRE(record.tasks["A"].children == std::unordered_set<std::string>{"B_0",  "B_1", "C"});
        REQUIRE(record.tasks["B_0"].children == std::unordered_set<std::string>{"C"});
        REQUIRE(record.tasks["B_1"].children == std::unordered_set<std::string>{"C"});
        REQUIRE(record.tasks["C"].children.empty());

    }
}