// demos_terminal.cpp — demos del modulo terminal_panel (issue 0132).
//
// Demo 1: One-shot — auto-launch al primer frame. Cross-platform:
//         Linux → bash "echo hello; date; ls /tmp | head"
//         Windows → cmd.exe "echo hello && date /t && dir /b %TEMP%"
// Demo 2: Interactivo — auto-launch al entrar al tab.
//         Linux → bash -i
//         Windows → cmd.exe
// Demo 3: Readonly — tail simulado en Linux / mensaje en Windows.
//
// Cambios issue 0132:
//   - Fondo negro + prompt input: en terminal_panel.cpp.
//   - Cross-platform: _WIN32 en todos los demos.
//   - Auto-launch: sin boton "Open shell" / "Run" en Demo 1 y Demo 2.

#include "demos.h"
#include "demo.h"
#include "viz/terminal_panel/terminal_panel.h"
#include "imgui.h"

#include <cstring>
#include <string>

// Para verificar que el binario del shell existe antes de abrir.
#ifdef _WIN32
#  ifndef WIN32_LEAN_AND_MEAN
#    define WIN32_LEAN_AND_MEAN
#  endif
#  include <windows.h>
   static bool shell_exists(const char* path) {
       return GetFileAttributesA(path) != INVALID_FILE_ATTRIBUTES;
   }
#else
#  include <unistd.h>
   static bool shell_exists(const char* path) {
       return access(path, X_OK) == 0;
   }
#endif

namespace gallery {

// ---------------------------------------------------------------------------
// Demo 1: One-shot con auto-launch
// ---------------------------------------------------------------------------

void demo_terminal_oneshot() {
    demo_header("terminal_panel", "v1.0.0",
        "Emulador TTY embebible. Demo 1: one-shot — auto-launch al primer frame, cross-platform.");

    static fn_term::TerminalPanel s_term;
    static bool s_launched = false;
    static bool s_shell_missing = false;

    if (!s_launched && !s_shell_missing) {
#ifdef _WIN32
        const char* sh = "cmd.exe";
        const char* cmd = "echo hello && date /t && dir /b %TEMP% 2>nul\r\n";
#else
        const char* sh = "/bin/bash";
        const char* cmd = "echo hello; date; ls /tmp | head -5; exit 0\n";
#endif
        if (!shell_exists(sh)) {
            s_shell_missing = true;
        } else {
            s_term.shell = sh;
            s_term.scrollback_lines = 200;
            s_term.readonly = true;
            fn_term::open(s_term);
            fn_term::send(s_term, cmd);
            s_launched = true;
        }
    }

    if (s_shell_missing) {
#ifdef _WIN32
        ImGui::TextColored(ImVec4(1.0f, 0.3f, 0.3f, 1.0f),
                           "Shell not available: cmd.exe");
#else
        ImGui::TextColored(ImVec4(1.0f, 0.3f, 0.3f, 1.0f),
                           "Shell not available: /bin/bash");
#endif
        return;
    }

    fn_term::render(s_term);

    if (s_term.process_exited.load() && s_term.is_open()) {
        ImGui::SameLine();
        ImGui::TextDisabled("[done — exit %d]", s_term.exit_code);
    }

    if (ImGui::Button("Reset demo")) {
        if (s_term.is_open()) fn_term::close(s_term);
        s_launched = false;
        s_shell_missing = false;
    }

    code_block(
#ifdef _WIN32
        "fn_term::TerminalPanel term;\n"
        "term.shell    = \"cmd.exe\";\n"
        "term.readonly = true;\n"
        "fn_term::open(term);\n"
        "fn_term::send(term, \"echo hello && date /t\\r\\n\");\n"
        "// En cada frame ImGui:\n"
        "fn_term::render(term);\n"
        "if (term.process_exited.load()) fn_term::close(term);"
#else
        "fn_term::TerminalPanel term;\n"
        "term.shell    = \"/bin/bash\";\n"
        "term.readonly = true;\n"
        "fn_term::open(term);\n"
        "fn_term::send(term, \"echo hello; date; exit 0\\n\");\n"
        "// En cada frame ImGui:\n"
        "fn_term::render(term);\n"
        "if (term.process_exited.load()) fn_term::close(term);"
#endif
    );
}

// ---------------------------------------------------------------------------
// Demo 2: Interactivo con auto-launch
// ---------------------------------------------------------------------------

void demo_terminal_interactive() {
    demo_header("terminal_panel", "v1.0.0",
        "Demo 2: terminal interactivo — auto-launch al entrar al tab. "
        "Linux: bash -i  /  Windows: cmd.exe.");

    static fn_term::TerminalPanel s_term;
    static bool s_launched = false;
    static bool s_shell_missing = false;

    // Auto-launch en el primer frame que se renderiza esta demo.
    if (!s_launched && !s_shell_missing) {
#ifdef _WIN32
        const char* sh = "cmd.exe";
#else
        const char* sh = "/bin/bash";
#endif
        if (!shell_exists(sh)) {
            s_shell_missing = true;
        } else {
            s_term.shell = sh;
            s_term.scrollback_lines = 1000;
            s_term.readonly = false;
            fn_term::open(s_term);
            s_launched = true;
        }
    }

    if (s_shell_missing) {
#ifdef _WIN32
        ImGui::TextColored(ImVec4(1.0f, 0.3f, 0.3f, 1.0f),
                           "Shell not available: cmd.exe");
#else
        ImGui::TextColored(ImVec4(1.0f, 0.3f, 0.3f, 1.0f),
                           "Shell not available: /bin/bash");
#endif
        return;
    }

    fn_term::render(s_term);

    if (s_term.is_open()) {
        ImGui::Spacing();
        if (ImGui::Button("Close shell")) {
            fn_term::close(s_term);
            s_launched = false;
        }
    } else if (s_launched) {
        ImGui::TextDisabled("[shell exited — click Reopen]");
        ImGui::SameLine();
        if (ImGui::Button("Reopen")) {
            s_launched = false;
            s_shell_missing = false;
        }
    }
}

// ---------------------------------------------------------------------------
// Demo 3: Readonly tail (Linux) / mensaje informativo (Windows)
// ---------------------------------------------------------------------------

void demo_terminal_readonly() {
    demo_header("terminal_panel", "v1.0.0",
        "Demo 3: readonly — "
#ifdef _WIN32
        "demo disponible solo en Linux (tail -f). En Windows se muestra un mensaje.");
#else
        "tail de /tmp/fn_gallery_test.log (creado al abrir).");
#endif

#ifdef _WIN32
    // En Windows nativo, tail -f no existe y /tmp tampoco.
    // Mostramos un panel readonly con mensaje estático para seguir ejercitando el render.
    static fn_term::TerminalPanel s_term;
    static bool s_launched = false;

    if (!s_launched) {
        s_term.shell    = "cmd.exe";
        s_term.readonly = true;
        s_term.scrollback_lines = 100;
        fn_term::open(s_term);
        // Imprimir unas líneas de muestra y terminar el proceso.
        fn_term::send(s_term,
            "echo [terminal_panel demo 3 - readonly] && "
            "echo This demo uses tail -f on Linux. && "
            "echo On Windows the panel renders static output. && "
            "exit 0\r\n");
        s_launched = true;
    }

    fn_term::render(s_term);

    if (ImGui::Button("Reset demo")) {
        if (s_term.is_open()) fn_term::close(s_term);
        s_launched = false;
    }
#else
    static fn_term::TerminalPanel s_term;
    static bool s_log_created = false;

    if (!s_log_created) {
        if (ImGui::Button("Start tail")) {
            FILE* f = fopen("/tmp/fn_gallery_test.log", "w");
            if (f) {
                for (int i = 0; i < 5; i++)
                    fprintf(f, "[sample] log line %d\n", i);
                fclose(f);
            }
            s_term.shell    = "/bin/bash";
            s_term.readonly = true;
            s_term.scrollback_lines = 500;
            fn_term::open(s_term);
            fn_term::send(s_term, "tail -f /tmp/fn_gallery_test.log\n");
            s_log_created = true;
        }
        return;
    }

    fn_term::render(s_term);

    ImGui::Separator();
    if (ImGui::Button("Append line")) {
        FILE* f = fopen("/tmp/fn_gallery_test.log", "a");
        if (f) {
            static int s_count = 0;
            fprintf(f, "[appended] line %d\n", s_count++);
            fclose(f);
        }
    }
    ImGui::SameLine();
    if (ImGui::Button("Stop")) {
        if (s_term.is_open()) fn_term::close(s_term);
        s_log_created = false;
    }

    code_block(
        "fn_term::TerminalPanel term;\n"
        "term.shell    = \"/bin/bash\";\n"
        "term.readonly = true;          // sin input box\n"
        "fn_term::open(term);\n"
        "fn_term::send(term, \"tail -f /tmp/agent.log\\n\");\n"
        "// En cada frame:\n"
        "fn_term::render(term);"
    );
#endif
}

// ---------------------------------------------------------------------------
// Entry point unificado (llamado desde main.cpp via demos.h)
// ---------------------------------------------------------------------------

void demo_terminal() {
    static int s_tab = 0;
    if (ImGui::BeginTabBar("##term_tabs")) {
        if (ImGui::BeginTabItem("One-shot")) {
            s_tab = 0;
            ImGui::EndTabItem();
        }
        if (ImGui::BeginTabItem("Interactive")) {
            s_tab = 1;
            ImGui::EndTabItem();
        }
        if (ImGui::BeginTabItem("Readonly tail")) {
            s_tab = 2;
            ImGui::EndTabItem();
        }
        ImGui::EndTabBar();
    }

    switch (s_tab) {
    case 0: demo_terminal_oneshot();     break;
    case 1: demo_terminal_interactive(); break;
    case 2: demo_terminal_readonly();    break;
    }
}

} // namespace gallery