#include "app_base.h"
#include "imgui.h"

#include "core/fullscreen_window.h"
#include "core/app_about.h"
#include "core/app_settings.h"
#include "core/panel_menu.h"
#include "core/button.h"
#include "core/tokens.h"

#include "viz/graph_types.h"
#include "viz/graph_viewport.h"
#include "viz/graph_renderer.h"
#include "viz/graph_force_layout.h"
#include "viz/graph_force_layout_gpu.h"
#include "viz/graph_layouts.h"
#include "viz/graph_labels.h"
#include "viz/graph_icons.h"
#include "viz/graph_sources.h"

#include "data.h"
#include "views.h"
#include "types_registry.h"
#include "layout_store.h"

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <chrono>
#include <string>

// ----------------------------------------------------------------------------
// Estado global de la app
// ----------------------------------------------------------------------------

static GraphData              g_graph{};
static GraphViewportState     g_viewport;
static ge::AppState           g_app;

static ge::InputArgs          g_input;
static std::string            g_input_path;       // copia para que .uri sea estable
static std::string            g_types_path;
static std::string            g_layout_initial;   // --layout flag
static uint64_t               g_graph_hash = 0;
static bool                   g_loaded = false;

// Force layout GPU context (lazy init).
static ForceLayoutGPU*        g_gpu_ctx   = nullptr;
static bool                   g_gpu_dirty = true;

// Icon atlas (de types.yaml)
static IconAtlas*             g_atlas       = nullptr;
static bool                   g_atlas_bound = false;

// Para detectar primera invocacion de viewport (necesitamos el renderer creado)
static bool                   g_first_render = true;

// FPS estimate
static auto                   g_last_frame = std::chrono::steady_clock::now();
static int                    g_frames_acc = 0;
static auto                   g_fps_timer  = std::chrono::steady_clock::now();

// Label policy
static graph::LabelPolicy     g_label_policy;

// ----------------------------------------------------------------------------
// Helpers
// ----------------------------------------------------------------------------

static int layout_name_to_index(const std::string& s) {
    if (s == "force")        return 0;
    if (s == "grid")         return 1;
    if (s == "circular")     return 2;
    if (s == "radial")       return 3;
    if (s == "hierarchical") return 4;
    if (s == "fixed")        return 5;
    return -1;
}

static void apply_static_layout(int mode) {
    if (g_graph.node_count == 0) return;
    switch (mode) {
        case 1: graph::layout_grid(g_graph, 20.0f); break;
        case 2: graph::layout_circular(g_graph, 200.0f); break;
        case 3: graph::layout_radial(g_graph, 0, 80.0f); break;
        case 4: graph::layout_hierarchical(g_graph, 0, 120.0f, 60.0f); break;
        case 5: graph::layout_fixed(g_graph); break;
        case 0: default: break; // force: no-op (lo mueve el bucle)
    }
    g_gpu_dirty = true;
    if (mode != 0) {
        g_graph.update_bounds();
        graph_viewport_fit(g_graph, g_viewport);
    }
}

static bool load_input() {
    g_input.kind = ge::INPUT_OPERATIONS;
    g_input.uri  = g_input_path.c_str();

    graph::GraphLoadStats stats{};
    bool ok = ge::load_graph(g_input, &g_graph, &stats);
    if (!ok) {
        std::fprintf(stderr, "[graph_explorer] load failed: %s\n", stats.error_msg);
        return false;
    }
    std::fprintf(stdout,
        "[graph_explorer] loaded %d nodes, %d edges, %d types, %d rel_types from %s\n",
        stats.nodes_loaded, stats.edges_loaded,
        stats.types_discovered, stats.rel_types_discovered, g_input.uri);

    // types.yaml
    if (!g_types_path.empty()) {
        ge::ParsedTypes pt;
        std::string err;
        if (!ge::types_load_yaml(g_types_path.c_str(), &pt, &err)) {
            std::fprintf(stderr, "[graph_explorer] types.yaml: %s\n", err.c_str());
        } else {
            std::vector<uint16_t> codepoints = ge::apply_types_yaml(g_graph, pt);
            // Reset atlas — la prox vez que el viewport tenga renderer, se baja
            g_atlas_bound = false;
            if (g_atlas) { graph_icons_destroy(g_atlas); g_atlas = nullptr; }
            g_atlas = ge::build_icon_atlas(codepoints);
            std::fprintf(stdout,
                "[graph_explorer] types.yaml: %zu entities, %zu relations, %zu icons\n",
                pt.entities.size(), pt.relations.size(), codepoints.size());
        }
    }

    // Restablecer viewport state (preserva camara user-visible)
    g_viewport.selection.clear();
    g_viewport.hovered_node = -1;
    g_viewport.selected_node = -1;
    g_viewport.layout_running = true;
    g_viewport.layout_energy  = 0.0f;

    // Posicionar nodos: si todos tienen (x,y)=0, aplicar layout circular como
    // arranque (grafos cargados desde operations.db vienen sin posiciones).
    int zero_pos = 0;
    for (int i = 0; i < g_graph.node_count; ++i) {
        if (g_graph.nodes[i].x == 0.0f && g_graph.nodes[i].y == 0.0f) ++zero_pos;
    }
    if (zero_pos == g_graph.node_count) {
        graph::layout_circular(g_graph, 200.0f);
    }
    g_graph.update_bounds();

    // Cargar posiciones guardadas para este graph_hash
    g_graph_hash = ge::compute_graph_hash(g_input.uri);
    int restored = ge::layout_store_load(g_graph_hash, g_graph);
    if (restored > 0) {
        std::fprintf(stdout, "[graph_explorer] restored %d node positions from layout store\n", restored);
        g_graph.update_bounds();
    }

    // Vista inicial
    graph_viewport_fit(g_graph, g_viewport);
    g_gpu_dirty = true;

    // App state — visibility por tipo
    g_app.graph    = &g_graph;
    g_app.viewport = &g_viewport;
    ge::views_reset_visibility(g_app);
    ge::views_apply_visibility(g_app);

    // --layout inicial (si llego del CLI)
    int idx = layout_name_to_index(g_layout_initial);
    if (idx >= 0) {
        g_app.layout_mode = idx;
        apply_static_layout(idx);
    }

    g_loaded = true;
    return true;
}

static void run_force_step() {
    if (!g_viewport.layout_running) return;
    if (g_app.layout_mode != 0) return; // force solo en mode 0

    ForceLayoutConfig cfg;
    cfg.repulsion  = g_app.repulsion;
    cfg.attraction = g_app.attraction;
    cfg.gravity    = g_app.gravity;
    cfg.iterations = 1;

    if (g_app.use_gpu) {
        if (!g_gpu_ctx) {
            g_gpu_ctx = graph_force_layout_gpu_create(g_graph.node_count + 1024,
                                                       g_graph.edge_count + 1024);
            g_gpu_dirty = true;
        }
        if (g_gpu_ctx) {
            if (g_gpu_dirty) {
                graph_force_layout_gpu_upload(g_gpu_ctx, g_graph);
                g_gpu_dirty = false;
            }
            g_viewport.layout_energy = graph_force_layout_gpu_step(g_gpu_ctx, cfg);
            graph_force_layout_gpu_readback(g_gpu_ctx, g_graph, /*include_velocities=*/true);
        } else {
            g_app.use_gpu = false;
            g_viewport.layout_energy = graph_force_layout_step(g_graph, cfg);
        }
    } else {
        g_viewport.layout_energy = graph_force_layout_step(g_graph, cfg);
    }

    // Auto-pause heuristica: si energia/nodo es muy baja durante muchos
    // frames, apagar simulacion. El usuario puede reanudarla con el toggle.
    static int low = 0;
    const float k_pause_per_node = 0.001f;
    const int   k_pause_after    = 60;
    float per = g_graph.node_count > 0
                    ? g_viewport.layout_energy / (float)g_graph.node_count
                    : 0.0f;
    if (per < k_pause_per_node) ++low;
    else                         low = 0;
    if (graph_force_layout_should_pause(low, k_pause_after)) {
        g_viewport.layout_running = false;
        low = 0;
    }
}

// FPS estimate sintetico (por segundo).
static void update_fps() {
    using namespace std::chrono;
    auto now = steady_clock::now();
    ++g_frames_acc;
    if (duration_cast<milliseconds>(now - g_fps_timer).count() >= 1000) {
        g_app.fps_estimate = g_frames_acc;
        g_frames_acc = 0;
        g_fps_timer = now;
    }
    g_last_frame = now;
}

// ----------------------------------------------------------------------------
// Label callback
// ----------------------------------------------------------------------------

static const char* get_label_cb(int node_idx, void* /*user*/) {
    if (node_idx < 0 || node_idx >= g_graph.node_count) return "";
    const GraphNode& n = g_graph.nodes[node_idx];
    return graph::graph_label(&g_graph, n.label_idx);
}

// ----------------------------------------------------------------------------
// Render
// ----------------------------------------------------------------------------

static fn_ui::PanelToggle g_panels[] = {
    {"Legend",    nullptr, &g_app.panel_legend},
    {"Inspector", nullptr, &g_app.panel_inspector},
    {"Stats",     nullptr, &g_app.panel_stats},
};

static void render() {
    update_fps();

    // No tenemos menu propio — fn::run_app llamara al app_menubar via panels[].

    if (!g_loaded) {
        fullscreen_window_begin("##empty");
        ImGui::TextColored(ImVec4(1, 0.7f, 0.3f, 1),
                           "graph_explorer — no input loaded");
        ImGui::Spacing();
        ImGui::TextWrapped(
            "Usage: graph_explorer [<operations.db>] [--input operations <path>] "
            "[--types <yaml>] [--layout <name>]");
        ImGui::Spacing();
        ge::views_open_modal(g_app);
        if (g_app.want_open_file) {
            g_input_path = g_app.open_buf;
            g_app.want_open_file = false;
            load_input();
        }
        if (fn_ui::button("Open file...", fn_ui::ButtonVariant::Primary)) {
            g_app.show_open_modal = true;
        }
        fullscreen_window_end();
        return;
    }

    // Toolbar superior — usa una ventana sin scroll y sin titulo
    ImGuiViewport* vp = ImGui::GetMainViewport();
    ImGui::SetNextWindowPos(vp->WorkPos);
    ImGui::SetNextWindowSize(ImVec2(vp->WorkSize.x, 44.0f));
    ImGui::Begin("##toolbar", nullptr,
                 ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize |
                 ImGuiWindowFlags_NoMove     | ImGuiWindowFlags_NoCollapse |
                 ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoScrollWithMouse |
                 ImGuiWindowFlags_NoSavedSettings);
    ge::views_toolbar(g_app);
    ImGui::End();

    // Modals
    ge::views_open_modal(g_app);
    ge::views_filters_modal(g_app);

    // Si el usuario aplico nuevo layout en la toolbar
    if (g_app.apply_layout_tick > 0) {
        apply_static_layout(g_app.layout_mode);
        g_app.apply_layout_tick = 0;
    }

    // Triggers desde la toolbar
    if (g_app.want_fit) {
        graph_viewport_fit(g_graph, g_viewport);
        g_app.want_fit = false;
    }
    if (g_app.want_reload) {
        g_app.want_reload = false;
        graph::GraphLoadStats stats{};
        if (ge::reload_graph(g_input, &g_graph, &stats)) {
            ge::views_reset_visibility(g_app);
            ge::views_apply_visibility(g_app);
            g_graph.update_bounds();
            graph_viewport_fit(g_graph, g_viewport);
            int restored = ge::layout_store_load(g_graph_hash, g_graph);
            if (restored > 0) g_graph.update_bounds();
            g_atlas_bound = false; // re-bind atlas tras reload
            g_gpu_dirty = true;
        }
    }
    if (g_app.want_save_layout) {
        int n = ge::layout_store_save(g_graph_hash, g_graph);
        std::fprintf(stdout, "[graph_explorer] saved %d node positions\n", n);
        g_app.want_save_layout = false;
    }
    if (g_app.want_open_file) {
        g_input_path = g_app.open_buf;
        g_app.want_open_file = false;
        // Cleanup viejo grafo
        graph::graph_free(&g_graph);
        load_input();
    }

    // Main work area — viewport central, paneles laterales
    ImGui::SetNextWindowPos(ImVec2(vp->WorkPos.x, vp->WorkPos.y + 44.0f));
    ImGui::SetNextWindowSize(ImVec2(vp->WorkSize.x, vp->WorkSize.y - 44.0f));
    ImGui::Begin("##main", nullptr,
                 ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize |
                 ImGuiWindowFlags_NoMove     | ImGuiWindowFlags_NoCollapse |
                 ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoSavedSettings);

    ImGui::Columns(3, "##cols", true);
    static bool s_cols_initialized = false;
    if (!s_cols_initialized) {
        ImGui::SetColumnWidth(0, 220.0f);
        ImGui::SetColumnWidth(1, vp->WorkSize.x - 220.0f - 320.0f);
        s_cols_initialized = true;
    }

    // Col izq: Legend
    ge::views_legend(g_app);
    ImGui::NextColumn();

    // Col centro: Viewport + force step + labels overlay
    run_force_step();

    graph_viewport("##gv", g_graph, g_viewport, ImVec2(0, 0));

    // La primera vez que el viewport se dibuja, el renderer existe — bind
    // del atlas (si tenemos uno).
    if (!g_atlas_bound && g_viewport.renderer) {
        if (g_atlas) {
            graph_renderer_set_icon_atlas(g_viewport.renderer,
                                           graph_icons_texture(g_atlas),
                                           graph_icons_uv_table(g_atlas),
                                           graph_icons_count(g_atlas));
        }
        g_atlas_bound = true;
    }

    if (g_app.labels_enabled) {
        graph::graph_labels_draw(g_graph, g_viewport, g_label_policy,
                                  &get_label_cb, nullptr);
    }
    ImGui::NextColumn();

    // Col der: Inspector + Stats
    ge::views_inspector(g_app);
    ge::views_stats(g_app);
    ImGui::NextColumn();

    ImGui::Columns(1);
    ImGui::End();

    g_first_render = false;
}

// ----------------------------------------------------------------------------
// CLI parsing
// ----------------------------------------------------------------------------

static void usage() {
    std::fprintf(stderr,
        "Usage: graph_explorer [<operations.db>]\n"
        "       graph_explorer --input operations <path>\n"
        "       graph_explorer --types <types.yaml>\n"
        "       graph_explorer --layout force|grid|circular|radial|hierarchical|fixed\n");
}

int main(int argc, char** argv) {
    for (int i = 1; i < argc; ++i) {
        const char* a = argv[i];
        if (std::strcmp(a, "--input") == 0 && i + 2 < argc) {
            const char* kind = argv[++i];
            const char* path = argv[++i];
            if (std::strcmp(kind, "operations") == 0) {
                g_input_path = path;
            } else {
                std::fprintf(stderr, "[graph_explorer] unsupported input kind: %s\n", kind);
                return 1;
            }
        } else if (std::strcmp(a, "--types") == 0 && i + 1 < argc) {
            g_types_path = argv[++i];
        } else if (std::strcmp(a, "--layout") == 0 && i + 1 < argc) {
            g_layout_initial = argv[++i];
        } else if (std::strcmp(a, "--help") == 0 || std::strcmp(a, "-h") == 0) {
            usage();
            return 0;
        } else if (a[0] == '-') {
            std::fprintf(stderr, "[graph_explorer] unknown flag: %s\n", a);
            usage();
            return 1;
        } else {
            // Positional: tratado como operations.db
            if (g_input_path.empty()) g_input_path = a;
        }
    }

    // SQLite store junto al exe.
    ge::layout_store_open("graph_explorer.db");

    if (!g_input_path.empty()) {
        load_input();
    }

    fn_ui::about_window_set_info(
        "graph_explorer",
        "0.1.0",
        "Visor de grafos GPU-accelerated agnostico del backend. Lee operations.db de "
        "cualquier app del registry y permite explorar entidades/relaciones con "
        "shapes/iconos/layouts/filtros.");

    int rc = fn::run_app(
        {.title          = "graph_explorer",
         .width          = 1600,
         .height         = 1000,
         .viewports      = true,
         .panels         = g_panels,
         .panel_count    = sizeof(g_panels) / sizeof(g_panels[0]),
         .init_gl_loader = true},
        render);

    // Cleanup
    if (g_gpu_ctx) graph_force_layout_gpu_destroy(g_gpu_ctx);
    if (g_atlas)   graph_icons_destroy(g_atlas);
    graph_viewport_destroy(g_viewport);
    graph::graph_free(&g_graph);
    ge::layout_store_close();

    return rc;
}