#include <imgui.h>
#include "app_base.h"
#include "core/panel_menu.h"
#include "core/icons_tabler.h"
#include "core/logger.h"
#include "data_http.h"
#include "http_client.h"
#include "ws_client.h"
#include "tabs.h"
#include "vendor/nlohmann/json.hpp"

#include <cstdio>
#include <cstring>
#include <string>
#include <vector>

using json = nlohmann::json;

// Config global del backend HTTP.
static std::string g_api_url      = "http://127.0.0.1:8090";
static std::string g_ws_host      = "127.0.0.1";
static int         g_ws_port      = 8090;
static std::string g_ws_path      = "/api/ws/dagruns";

// Cache en memoria del primer fetch + ultimos eventos WS.
static std::vector<dag_ui::DagInfo>  g_dags;
static std::vector<dag_ui::DagRunRow> g_live_runs;     // upsert por id desde WS
static std::vector<dag_ui::DagRunRow> g_runs_all;      // cache para Timeline (snapshot REST + WS upsert)
static long long                     g_ws_runs_wm  = 0;
static long long                     g_ws_steps_wm = 0;
static int                           g_ws_msg_count = 0;
static std::string                   g_last_error;

// Upsert por id en g_runs_all. Mantiene mas reciente al frente.
static void upsert_run_in_all(const dag_ui::DagRunRow& r) {
    for (auto& existing : g_runs_all) {
        if (existing.id == r.id) {
            existing = r;
            return;
        }
    }
    g_runs_all.push_back(r);
}

static WsClient g_ws;

// Toggles de paneles (visibles desde el menu View del menubar canonico)
static bool g_show_main       = false;  // diagnostico, off por defecto
static bool g_show_live       = true;
static bool g_show_dag_list   = true;
static bool g_show_dag_detail = true;
static bool g_show_run_detail = true;
static bool g_show_timeline   = true;
static bool g_show_all_runs   = true;
static bool g_show_health     = true;
static bool g_show_function_panel = true;

// Auto-fetch DAG list una vez al arrancar.
static bool g_initial_fetched = false;
// Flag set by tabs::draw_dag_list cuando el usuario pulsa Refresh, o cuando
// WS notifica que un run termino (status != running) — re-fetch /api/dags
// para actualizar last_runs.
static bool g_refresh_pending = false;

extern "C" void dag_list_request_refresh() { g_refresh_pending = true; }

// Upsert por id en g_live_runs.
static void upsert_live_run(const dag_ui::DagRunRow& r) {
    for (auto& existing : g_live_runs) {
        if (existing.id == r.id) {
            existing = r;
            return;
        }
    }
    g_live_runs.push_back(r);
}

static void parse_ws_payload(const std::string& payload) {
    auto j = json::parse(payload, nullptr, false);
    if (!j.is_object()) return;
    g_ws_msg_count++;
    if (j.contains("watermark") && j["watermark"].is_object()) {
        if (j["watermark"].contains("runs"))  g_ws_runs_wm  = j["watermark"]["runs"].get<long long>();
        if (j["watermark"].contains("steps")) g_ws_steps_wm = j["watermark"]["steps"].get<long long>();
    }
    if (j.contains("runs") && j["runs"].is_array()) {
        for (auto& rj : j["runs"]) {
            dag_ui::DagRunRow r;
            r.id          = rj.value("id", "");
            r.dag_name    = rj.value("dag_name", "");
            r.status      = rj.value("status", "");
            r.trigger     = rj.value("trigger", "");
            r.started_at  = rj.value("started_at", "");
            r.finished_at = rj.value("finished_at", "");
            r.error       = rj.value("error", "");
            upsert_live_run(r);
            upsert_run_in_all(r);
            // Cuando un run termina, refresca DAG List para que last_runs
            // refleje la nueva ejecucion en R1..R5.
            if (r.status == "success" || r.status == "failed" ||
                r.status == "cancelled") {
                g_refresh_pending = true;
            }
        }
    }
}

static void draw_main() {
    if (!ImGui::Begin(TI_HOME " Main", &g_show_main)) {
        ImGui::End();
        return;
    }
    ImGui::Text("API: %s", g_api_url.c_str());
    if (ImGui::Button("Fetch /api/dags")) {
        g_dags.clear();
        g_last_error.clear();
        if (!dag_ui::list_dags_http(g_api_url, g_dags)) {
            g_last_error = "list_dags_http failed (see stderr)";
        }
    }
    if (!g_last_error.empty()) {
        ImGui::TextColored(ImVec4(1, 0.4f, 0.4f, 1), "%s", g_last_error.c_str());
    }
    ImGui::Separator();
    ImGui::Text("DAGs: %zu", g_dags.size());
    for (auto& d : g_dags) {
        ImGui::BulletText("%s  (%s)  schedule=%s",
                          d.name.c_str(),
                          d.valid ? "valid" : "invalid",
                          d.schedule.empty() ? "none" : d.schedule[0].c_str());
    }
    ImGui::End();
}

static void draw_live() {
    if (!ImGui::Begin(TI_BOLT " Live (WS)", &g_show_live)) {
        ImGui::End();
        return;
    }
    bool connected = g_ws.is_connected();
    ImGui::TextColored(connected ? ImVec4(0.3f, 0.9f, 0.3f, 1) : ImVec4(0.9f, 0.4f, 0.4f, 1),
                       "%s", connected ? "connected" : "disconnected");
    ImGui::SameLine();
    ImGui::Text("| msgs=%d | wm runs=%lld steps=%lld",
                g_ws_msg_count, g_ws_runs_wm, g_ws_steps_wm);
    ImGui::Separator();
    ImGui::Text("Live runs: %zu", g_live_runs.size());
    for (auto& r : g_live_runs) {
        ImGui::BulletText("%s [%s] %s @ %s",
                          r.dag_name.c_str(), r.status.c_str(),
                          r.id.c_str(), r.started_at.c_str());
    }
    ImGui::End();
}

static void render() {
    // Auto-fetch DAGs on first frame or on explicit refresh.
    if (!g_initial_fetched || g_refresh_pending) {
        g_initial_fetched = true;
        g_refresh_pending = false;
        dag_ui::list_dags_http(g_api_url, g_dags);
        // Tambien snapshot inicial / refresh de runs para Timeline.
        std::vector<dag_ui::DagRunRow> tmp;
        if (dag_ui::list_runs_http(g_api_url, "", 200, tmp)) {
            for (auto& r : tmp) upsert_run_in_all(r);
        }
    }

    // Drain WS messages this frame (cheap, max 64).
    {
        std::vector<std::string> msgs;
        g_ws.drain(msgs, 64);
        for (auto& m : msgs) parse_ws_payload(m);
    }

    if (g_show_dag_list)   dag_ui_tabs::draw_dag_list(g_api_url, g_dags, g_live_runs);
    if (g_show_dag_detail) dag_ui_tabs::draw_dag_detail(g_api_url);
    if (g_show_run_detail) dag_ui_tabs::draw_run_detail(g_api_url);
    if (g_show_timeline)   dag_ui_tabs::draw_timeline(g_api_url, g_runs_all);
    if (g_show_all_runs)   dag_ui_tabs::draw_all_runs(g_api_url, g_runs_all);
    if (g_show_health)     dag_ui_tabs::draw_health(g_api_url, g_runs_all);
    if (g_show_main)       draw_main();
    if (g_show_live)       draw_live();
    if (g_show_function_panel) dag_ui_tabs::draw_function_panel(g_api_url, &g_show_function_panel);
}

// Self-test: blocking HTTP GET to the dag_engine backend, no GUI.
// Returns 0 if reachable (any 2xx), 1 otherwise.
static int run_self_test() {
    HttpClient client(g_ws_host, g_ws_port);
    // Probe /api/dags as a sucedaneo de /health (no dedicated /health helper).
    HttpResponse resp = client.get("/api/dags");
    if (resp.ok()) {
        std::printf("self-test ok: dag_engine reachable at %s\n", g_api_url.c_str());
        return 0;
    }
    std::printf("self-test fail: dag_engine unreachable at %s (status=%d)\n",
                g_api_url.c_str(), resp.status);
    return 1;
}

int main(int argc, char** argv) {
    // CLI flag --self-test: probe backend and exit without opening GUI.
    for (int i = 1; i < argc; i++) {
        if (argv[i] && std::strcmp(argv[i], "--self-test") == 0) {
            return run_self_test();
        }
    }

    // Conecta WS al backend dag_engine. Reconnect con backoff lo gestiona WsClient.
    g_ws.start(g_ws_host, g_ws_port, g_ws_path);

    static fn_ui::PanelToggle panels[] = {
        { "DAGs",        nullptr, &g_show_dag_list },
        { "DAG Detail",  nullptr, &g_show_dag_detail },
        { "Run Detail",  nullptr, &g_show_run_detail },
        { "Timeline",    nullptr, &g_show_timeline },
        { "All Runs",    nullptr, &g_show_all_runs },
        { "Health",      nullptr, &g_show_health },
        { "Function",    nullptr, &g_show_function_panel },
        { "Live (WS)",   nullptr, &g_show_live },
        { "Main (diag)", nullptr, &g_show_main },
    };

    fn::AppConfig cfg;
    cfg.title       = "dag_engine_ui — Frontend ImGui para dag_engine. Lista, lanza e inspecciona DAGs con live updates via WS.";
    cfg.about       = { "dag_engine_ui", "0.1.0", "Frontend ImGui para dag_engine. Lista, lanza e inspecciona DAGs con live updates via WS." };
    cfg.log         = { "dag_engine_ui.log", 1 };
    cfg.panels      = panels;
    cfg.panel_count = sizeof(panels) / sizeof(panels[0]);

    return fn::run_app(cfg, render);
}