// velox — the command-line client for veloxd.
//
//   velox add <url> [--dir D] [--out NAME] [--segments N] [--json]
//   velox ls [--json]
//   velox pause <id>...            velox resume <id>...
//   velox rm <id>... [--delete-file]
//
// Exit codes: 0 ok, 1 daemon returned an error, 2 usage error, 3 cannot reach the daemon.

#include <cstdio>
#include <cstdlib>
#include <string>
#include <string_view>
#include <vector>

#include <nlohmann/json.hpp>

#include "client.hpp"

namespace {

using nlohmann::json;
using velox::cli::CallError;
using velox::cli::Client;

constexpr int kOk = 0;
constexpr int kRpcError = 1;
constexpr int kUsage = 2;
constexpr int kNoDaemon = 3;

struct Args {
    std::vector<std::string> positional;
    bool json = false;
    bool delete_file = false;
    std::string dir;
    std::string out;
    long segments = 0;
};

[[noreturn]] void usage(int code) {
    std::fprintf(code == kOk ? stdout : stderr,
                 "usage: velox <command> [options]\n\n"
                 "  add <url> [--dir DIR] [--out NAME] [--segments N]\n"
                 "  ls\n"
                 "  pause <id>...\n"
                 "  resume <id>...\n"
                 "  rm <id>... [--delete-file]\n\n"
                 "  --json   print the raw JSON-RPC result\n");
    std::exit(code);
}

Args parse_args(int argc, char** argv) {
    Args a;
    for (int i = 2; i < argc; ++i) {
        const std::string_view arg = argv[i];
        if (arg == "--json") {
            a.json = true;
        } else if (arg == "--delete-file") {
            a.delete_file = true;
        } else if (arg == "--dir" && i + 1 < argc) {
            a.dir = argv[++i];
        } else if (arg == "--out" && i + 1 < argc) {
            a.out = argv[++i];
        } else if (arg == "--segments" && i + 1 < argc) {
            a.segments = std::strtol(argv[++i], nullptr, 10);
        } else if (arg == "-h" || arg == "--help") {
            usage(kOk);
        } else if (!arg.empty() && arg.front() == '-') {
            std::fprintf(stderr, "velox: unknown option %s\n", argv[i]);
            usage(kUsage);
        } else {
            a.positional.emplace_back(arg);
        }
    }
    return a;
}

int report_error(const CallError& e, bool as_json) {
    if (as_json) {
        json j = {{"error", {{"code", e.code}, {"message", e.message}}}};
        if (!e.data.is_null()) j["error"]["data"] = e.data;
        std::printf("%s\n", j.dump(2).c_str());
    } else {
        std::fprintf(stderr, "velox: %s\n", e.message.c_str());
    }
    return e.code == CallError::kConnect ? kNoDaemon : kRpcError;
}

void print_task_table(const json& items) {
    std::printf("%-38s  %-10s  %-9s  %s\n", "ID", "STATE", "PROGRESS", "NAME");
    for (const auto& t : items) {
        const std::string id = t.value("taskId", "");
        const std::string state = t.value("state", "");
        const std::string name = t.value("filename", "");
        const long long total = t.value("sizeBytes", 0LL);
        const long long done = t.value("downloadedBytes", 0LL);
        char pct[12] = "-";
        if (total > 0) std::snprintf(pct, sizeof(pct), "%lld%%", done * 100 / total);
        std::printf("%-38s  %-10s  %-9s  %s\n", id.c_str(), state.c_str(), pct, name.c_str());
    }
}

int cmd_ls(Client& c, const Args& a) {
    auto r = c.call("download.list", json::object());
    if (!r) return report_error(r.error(), a.json);
    if (a.json) {
        std::printf("%s\n", r->dump(2).c_str());
        return kOk;
    }
    const auto& items = r->contains("items") ? r->at("items") : json::array();
    if (items.empty()) {
        std::printf("no downloads\n");
        return kOk;
    }
    print_task_table(items);
    return kOk;
}

int cmd_add(Client& c, const Args& a) {
    if (a.positional.empty()) {
        std::fprintf(stderr, "velox add: a URL is required\n");
        return kUsage;
    }
    json params = {{"url", a.positional.front()}};
    if (!a.dir.empty()) params["saveDir"] = a.dir;
    if (!a.out.empty()) params["filename"] = a.out;
    if (a.segments > 0) params["segments"] = a.segments;

    auto r = c.call("download.add", params);
    if (!r) return report_error(r.error(), a.json);
    if (a.json) {
        std::printf("%s\n", r->dump(2).c_str());
    } else {
        std::printf("added %s\n", r->value("taskId", "?").c_str());
    }
    return kOk;
}

int cmd_bulk(Client& c, const Args& a, const char* method) {
    if (a.positional.empty()) {
        std::fprintf(stderr, "velox: at least one task id is required\n");
        return kUsage;
    }
    json params = {{"taskIds", a.positional}};
    if (std::string_view(method) == "download.remove" && a.delete_file) params["deleteFile"] = true;

    auto r = c.call(method, params);
    if (!r) return report_error(r.error(), a.json);
    if (a.json) {
        std::printf("%s\n", r->dump(2).c_str());
    } else {
        std::printf("ok\n");
    }
    return kOk;
}

}  // namespace

int main(int argc, char** argv) {
    if (argc < 2) usage(kUsage);
    const std::string command = argv[1];
    if (command == "-h" || command == "--help") usage(kOk);

    const Args args = parse_args(argc, argv);

    Client client;
    if (const auto err = client.connect()) {
        return report_error(*err, args.json);
    }

    if (command == "ls") return cmd_ls(client, args);
    if (command == "add") return cmd_add(client, args);
    if (command == "pause") return cmd_bulk(client, args, "download.pause");
    if (command == "resume") return cmd_bulk(client, args, "download.resume");
    if (command == "rm") return cmd_bulk(client, args, "download.remove");

    std::fprintf(stderr, "velox: unknown command '%s'\n", command.c_str());
    usage(kUsage);
}