/*
Crafter® Build
Copyright (C) 2026 Catcrafts®
Catcrafts.net

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License version 3.0 as published by the Free Software Foundation;

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
*/

module;
#include <stdio.h>
#include <stdlib.h>
#if defined(_WIN32)
    #include <io.h>
    #include <windows.h>
    #ifndef STDOUT_FILENO
        #define STDOUT_FILENO _fileno(stdout)
    #endif
    #define CRAFTER_PROGRESS_ISATTY _isatty
#else
    #include <unistd.h>
    #include <sys/ioctl.h>
    #define CRAFTER_PROGRESS_ISATTY isatty
#endif

export module Crafter.Build:Progress_impl;
import std;
import :Progress;

namespace {
    std::mutex g_mutex;
    std::atomic<int> g_total{0};
    std::atomic<int> g_done{0};
    Crafter::Progress::Verbosity g_verbosity = Crafter::Progress::Verbosity::Default;
    bool g_isTty = false;
    bool g_lineDirty = false;        // status line has uncleared content
    bool g_finalized = false;
    std::chrono::steady_clock::time_point g_startTime = std::chrono::steady_clock::now();

    int TerminalWidth() {
    #if defined(_WIN32)
        HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
        CONSOLE_SCREEN_BUFFER_INFO info;
        if (h != INVALID_HANDLE_VALUE && GetConsoleScreenBufferInfo(h, &info)) {
            int w = info.srWindow.Right - info.srWindow.Left + 1;
            if (w > 0) return w;
        }
    #else
        winsize ws{};
        if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == 0 && ws.ws_col > 0) {
            return ws.ws_col;
        }
    #endif
        if (const char* col = std::getenv("COLUMNS")) {
            try { int c = std::stoi(col); if (c > 0) return c; } catch (...) {}
        }
        return 80;
    }

    // Caller holds g_mutex.
    void RenderStatus(std::string_view label) {
        if (g_verbosity != Crafter::Progress::Verbosity::Default || !g_isTty) return;
        int done = g_done.load(std::memory_order_relaxed);
        int total = g_total.load(std::memory_order_relaxed);
        std::string prefix = std::format("[{}/{}] ", done, total);
        int width = TerminalWidth();
        int avail = width - static_cast<int>(prefix.size()) - 1;
        std::string trimmed{label};
        if (avail > 0 && static_cast<int>(trimmed.size()) > avail) {
            trimmed.resize(static_cast<std::size_t>(avail));
        }
        // \r returns to col 0, \033[2K erases the whole line. No newline.
        std::fputs("\r\033[2K", stdout);
        std::fputs(prefix.c_str(), stdout);
        std::fputs(trimmed.c_str(), stdout);
        std::fflush(stdout);
        g_lineDirty = true;
    }

    // Caller holds g_mutex.
    void ClearLineLocked() {
        if (g_lineDirty) {
            std::fputs("\r\033[2K", stdout);
            std::fflush(stdout);
            g_lineDirty = false;
        }
    }
}

namespace Crafter::Progress {

void SetVerbosity(Verbosity v) {
    std::lock_guard lock(g_mutex);
    g_verbosity = v;
    g_isTty = CRAFTER_PROGRESS_ISATTY(STDOUT_FILENO) != 0;
    g_startTime = std::chrono::steady_clock::now();
    g_total.store(0);
    g_done.store(0);
    g_finalized = false;
}

Verbosity GetVerbosity() {
    std::lock_guard lock(g_mutex);
    return g_verbosity;
}

Task::Task(std::string label) : label_(std::move(label)) {
    g_total.fetch_add(1, std::memory_order_relaxed);
    std::lock_guard lock(g_mutex);
    if (g_verbosity == Verbosity::Default && g_isTty) {
        RenderStatus(label_);
    }
}

Task::~Task() {
    int done = g_done.fetch_add(1, std::memory_order_relaxed) + 1;
    std::lock_guard lock(g_mutex);
    if (g_verbosity == Verbosity::Default) {
        if (g_isTty) {
            RenderStatus(label_);
        } else {
            // Non-TTY: one append-only line per completed task (ninja-style).
            int total = g_total.load(std::memory_order_relaxed);
            std::println("[{}/{}] {}", done, total, label_);
        }
    }
}

void EchoCommand(std::string_view command) {
    std::lock_guard lock(g_mutex);
    if (g_verbosity == Verbosity::Verbose) {
        std::println("$ {}", command);
    }
}

void Clear() {
    std::lock_guard lock(g_mutex);
    ClearLineLocked();
}

void Finalize() {
    std::lock_guard lock(g_mutex);
    if (g_finalized) return;
    g_finalized = true;
    ClearLineLocked();
    if (g_verbosity == Verbosity::Quiet) return;
    int done = g_done.load();
    if (done == 0) return;  // Nothing happened (cached build); stay silent.
    auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
        std::chrono::steady_clock::now() - g_startTime);
    std::println("Built {} step{} in {}ms",
        done, done == 1 ? "" : "s", elapsed.count());
}

} // namespace Crafter::Progress