// SPDX-License-Identifier: LGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

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 StateMutex;
    std::atomic<std::int32_t> Total{0};
    std::atomic<std::int32_t> Done{0};
    Crafter::Progress::Verbosity ActiveVerbosity = Crafter::Progress::Verbosity::Default;
    bool IsTty = false;
    bool LineDirty = false;        // status line has uncleared content
    bool Finalized = false;
    std::chrono::steady_clock::time_point StartTime = std::chrono::steady_clock::now();

    std::int32_t TerminalWidth() {
    #if defined(_WIN32)
        HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
        CONSOLE_SCREEN_BUFFER_INFO info;
        if (h != INVALID_HANDLE_VALUE && GetConsoleScreenBufferInfo(h, &info)) {
            std::int32_t 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 { std::int32_t c = std::stoi(col); if (c > 0) return c; } catch (...) {}
        }
        return 80;
    }

    // Caller holds StateMutex.
    void RenderStatus(std::string_view label) {
        if (ActiveVerbosity != Crafter::Progress::Verbosity::Default || !IsTty) return;
        std::int32_t done = Done.load(std::memory_order_relaxed);
        std::int32_t total = Total.load(std::memory_order_relaxed);
        std::string prefix = std::format("[{}/{}] ", done, total);
        std::int32_t width = TerminalWidth();
        std::int32_t avail = width - static_cast<std::int32_t>(prefix.size()) - 1;
        std::string trimmed{label};
        if (avail > 0 && static_cast<std::int32_t>(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);
        LineDirty = true;
    }

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

namespace Crafter::Progress {

void SetVerbosity(Verbosity v) {
    std::lock_guard lock(StateMutex);
    ActiveVerbosity = v;
    IsTty = CRAFTER_PROGRESS_ISATTY(STDOUT_FILENO) != 0;
    StartTime = std::chrono::steady_clock::now();
    Total.store(0);
    Done.store(0);
    Finalized = false;
}

Verbosity GetVerbosity() {
    std::lock_guard lock(StateMutex);
    return ActiveVerbosity;
}

Task::Task(std::string label) : label_(std::move(label)) {
    Total.fetch_add(1, std::memory_order_relaxed);
    std::lock_guard lock(StateMutex);
    if (ActiveVerbosity == Verbosity::Default && IsTty) {
        RenderStatus(label_);
    }
}

Task::~Task() {
    std::int32_t done = Done.fetch_add(1, std::memory_order_relaxed) + 1;
    std::lock_guard lock(StateMutex);
    if (ActiveVerbosity == Verbosity::Default) {
        if (IsTty) {
            RenderStatus(label_);
        } else {
            // Non-TTY: one append-only line per completed task (ninja-style).
            std::int32_t total = Total.load(std::memory_order_relaxed);
            std::println("[{}/{}] {}", done, total, label_);
        }
    }
}

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

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

void Finalize() {
    std::lock_guard lock(StateMutex);
    if (Finalized) return;
    Finalized = true;
    ClearLineLocked();
    if (ActiveVerbosity == Verbosity::Quiet) return;
    std::int32_t done = 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() - StartTime);
    std::println("Built {} step{} in {}ms", done, done == 1 ? "" : "s", elapsed.count());
}

} // namespace Crafter::Progress