// demos_terminal.cpp — demos del modulo terminal_panel (issue 0132).
//
// Demo 1: One-shot — spawn bash que ejecuta "echo hello; date; ls /tmp | head"
//         con auto-close cuando el proceso termina. Muestra el scrollback.
// Demo 2: Interactivo — bash -i (Linux) / cmd.exe (Windows) con input box.
// Demo 3: Readonly — tail simulado de un archivo de log.

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

#include <cstring>
#include <string>

namespace gallery {

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

void demo_terminal_oneshot() {
    demo_header("terminal_panel", "v1.0.0",
        "Emulador TTY embebible. Demo 1: one-shot — spawn bash, ejecuta comandos, auto-close.");

    static fn_term::TerminalPanel s_term;
    static bool s_started = false;

    if (!s_started) {
        ImGui::TextUnformatted("Pulsa 'Run' para lanzar el one-shot.");
        if (ImGui::Button("Run")) {
            if (!s_term.is_open()) {
                s_term.shell = "/bin/bash";
                s_term.scrollback_lines = 200;
                s_term.readonly = true; // solo output, sin input
                fn_term::open(s_term);
                fn_term::send(s_term, "echo hello; date; ls /tmp | head -5; exit 0\n");
                s_started = true;
            }
        }
        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_started = false;
    }

    code_block(
        "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);"
    );
}

// ---------------------------------------------------------------------------
// Demo 2: Interactivo
// ---------------------------------------------------------------------------

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

    static fn_term::TerminalPanel s_term;

    if (!s_term.is_open()) {
        if (ImGui::Button("Open shell")) {
#ifdef _WIN32
            s_term.shell = "cmd.exe";
#else
            s_term.shell = "/bin/bash";
#endif
            s_term.scrollback_lines = 1000;
            s_term.readonly = false;
            fn_term::open(s_term);
        }
        return;
    }

    fn_term::render(s_term);

    if (ImGui::Button("Close shell")) {
        fn_term::close(s_term);
    }
}

// ---------------------------------------------------------------------------
// Demo 3: Readonly tail
// ---------------------------------------------------------------------------

void demo_terminal_readonly() {
    demo_header("terminal_panel", "v1.0.0",
        "Demo 3: readonly — tail de /tmp/fn_gallery_test.log (creado al abrir).");

    static fn_term::TerminalPanel s_term;
    static bool s_log_created = false;

    // Crear el archivo de log de prueba si no existe.
    if (!s_log_created) {
        if (ImGui::Button("Start tail")) {
            // Escribir unas líneas de muestra al log.
            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);"
    );
}

// ---------------------------------------------------------------------------
// 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