#include "arg.h"
#include "common.h"
#include "log.h"

#include "cli-context.h"
#include "cli-view.h"

#include <array>
#include <algorithm>
#include <filesystem>
#include <string_view>
#include <signal.h>

#if defined(_WIN32)
#define WIN32_LEAN_AND_MEAN
#ifndef NOMINMAX
#   define NOMINMAX
#endif
#include <windows.h>
#endif

#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__)) || defined (_WIN32)
static void signal_handler(int) {
    if (g_cli_interrupted.load()) {
        // second Ctrl+C - exit immediately
        // make sure to clear colors before exiting (not using LOG or console.cpp here to avoid deadlock)
        fprintf(stdout, "\033[0m\n");
        fflush(stdout);
        std::exit(130);
    }
    g_cli_interrupted.store(true);
}
#endif

// TODO?: Make this reusable, enums, docs
static const std::array<std::string_view, 8> cmds = {
    "/audio ",
    "/clear",
    "/exit",
    "/glob ",
    "/image ",
    "/read ",
    "/regen",
    "/video ",
};

static std::vector<std::pair<std::string, size_t>> auto_completion_callback(std::string_view line, size_t cursor_byte_pos) {
    std::vector<std::pair<std::string, size_t>> matches;
    std::string cmd;

    if (line.length() > 1 && line.front() == '/' && !std::any_of(cmds.begin(), cmds.end(), [line](std::string_view prefix) {
        return string_starts_with(line, prefix);
    })) {
        auto it = cmds.begin();

        while ((it = std::find_if(it, cmds.end(), [line](std::string_view cmd_line) {
            return string_starts_with(cmd_line, line);
        })) != cmds.end()) {
            matches.emplace_back(*it, it->length());
            ++it;
        }
    } else {
        auto it = std::find_if(cmds.begin(), cmds.end(), [line](std::string_view prefix) {
            return prefix.back() == ' ' && string_starts_with(line, prefix);
        });

        if (it != cmds.end()) {
            cmd = *it;
        }
    }

    if (!cmd.empty() && cmd != "/glob " && line.length() >= cmd.length() && cursor_byte_pos >= cmd.length()) {
        const std::string path_prefix  = std::string(line.substr(cmd.length(), cursor_byte_pos - cmd.length()));
        const std::string path_postfix = std::string(line.substr(cursor_byte_pos));
        auto cur_dir = std::filesystem::current_path();
        std::string cur_dir_str = cur_dir.string();
        std::string expanded_prefix = path_prefix;

#if !defined(_WIN32)
        if (string_starts_with(path_prefix, '~')) {
            const char * home = std::getenv("HOME");
            if (home && home[0]) {
                expanded_prefix = home + path_prefix.substr(1);
            }
        }
        if (string_starts_with(expanded_prefix, '/')) {
#else
        if (std::isalpha(expanded_prefix[0]) && expanded_prefix.find(':') == 1) {
#endif
            cur_dir = std::filesystem::path(expanded_prefix).parent_path();
            cur_dir_str.clear();
        } else if (!path_prefix.empty()) {
            cur_dir /= std::filesystem::path(path_prefix).parent_path();
        }

        std::error_code ec;
        for (const auto & entry : std::filesystem::directory_iterator(cur_dir, ec)) {
            if (ec) {
                break;
            }
            if (!entry.exists(ec)) {
                ec.clear();
                continue;
            }

            const std::string path_full = entry.path().string();
            std::string path_entry = !cur_dir_str.empty() && string_starts_with(path_full, cur_dir_str) ? path_full.substr(cur_dir_str.length() + 1) : path_full;

            if (entry.is_directory(ec)) {
                path_entry.push_back(std::filesystem::path::preferred_separator);
            }

            if (expanded_prefix.empty() || string_starts_with(path_entry, expanded_prefix)) {
                const std::string updated_line = cmd + path_entry;
                matches.emplace_back(updated_line + path_postfix, updated_line.length());
            }

            if (ec) {
                ec.clear();
            }
        }

        if (matches.empty()) {
            const std::string updated_line = cmd + path_prefix;
            matches.emplace_back(updated_line + path_postfix, updated_line.length());
        }

        // Add the longest common prefix
        if (!expanded_prefix.empty() && matches.size() > 1) {
            const std::string_view match0(matches[0].first);
            const std::string_view match1(matches[1].first);
            auto it = std::mismatch(match0.begin(), match0.end(), match1.begin(), match1.end());
            size_t len = it.first - match0.begin();

            for (size_t i = 2; i < matches.size(); ++i) {
                const std::string_view matchi(matches[i].first);
                auto cmp = std::mismatch(match0.begin(), match0.end(), matchi.begin(), matchi.end());
                len = std::min(len, static_cast<size_t>(cmp.first - match0.begin()));
            }

            const std::string updated_line = std::string(match0.substr(0, len));
            matches.emplace_back(updated_line + path_postfix, updated_line.length());
        }

        std::sort(matches.begin(), matches.end(), [](const auto & a, const auto & b) {
            return a.first.compare(0, a.second, b.first, 0, b.second) < 0;
        });
    }

    return matches;
}

// satisfies -Wmissing-declarations
int llama_cli(int argc, char ** argv);

int llama_cli(int argc, char ** argv) {
    common_params params;

    params.verbosity = LOG_LEVEL_ERROR; // by default, less verbose logs

    common_init();

    if (!common_params_parse(argc, argv, params, LLAMA_EXAMPLE_CLI)) {
        return 1;
    }

    view::set_completion_callback(auto_completion_callback);

#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
    struct sigaction sigint_action;
    sigint_action.sa_handler = signal_handler;
    sigemptyset (&sigint_action.sa_mask);
    sigint_action.sa_flags = 0;
    sigaction(SIGINT, &sigint_action, NULL);
    sigaction(SIGTERM, &sigint_action, NULL);
#elif defined (_WIN32)
    auto console_ctrl_handler = +[](DWORD ctrl_type) -> BOOL {
        return (ctrl_type == CTRL_C_EVENT) ? (signal_handler(SIGINT), true) : false;
    };
    SetConsoleCtrlHandler(reinterpret_cast<PHANDLER_ROUTINE>(console_ctrl_handler), true);
#endif

    cli_context ctx_cli(params);

    if (!ctx_cli.init(argc, argv)) {
        ctx_cli.shutdown();
        return 1;
    }

    int ret = ctx_cli.run();

    ctx_cli.shutdown();

    return ret;
}