#include <stdbool.h>
#include <stdint.h>
#include <glib.h>
#include <gio/gio.h>
#include <json-glib/json-glib.h>
#include <json-glib/json-builder.h>

#include "dwm.h"
#include "log.h"

#define IPC_MAGIC "DWM-IPC"
#define IPC_MAGIC_LEN 7

typedef struct {
  uint8_t magic[IPC_MAGIC_LEN];
  uint32_t size;
  uint8_t type;
} __attribute__((packed)) DwmIpcHeader;

struct DwmIpc {
    GSocket *socket;
    GSource *source;
    State *state;
    Color color;
    Color text_color;
    Color selected;
    Button *tags[9];
    Button *title;
    bool change_title;
    bool hidden_title;
};

typedef enum {
    IPC_TYPE_RUN_COMMAND = 0,
    IPC_TYPE_GET_MONITORS = 1,
    IPC_TYPE_GET_TAGS = 2,
    IPC_TYPE_GET_LAYOUTS = 3,
    IPC_TYPE_GET_DWM_CLIENT = 4,
    IPC_TYPE_SUBSCRIBE = 5,
    IPC_TYPE_EVENT = 6
} DwmIpcMessage;

#define IPC_EVENT_TAG_CHANGE "tag_change_event"
#define IPC_EVENT_CLIENT_FOCUS_CHANGE "client_focus_change_event"
#define IPC_EVENT_LAYOUT_CHANGE "layout_change_event"
#define IPC_EVENT_MONITOR_FOCUS_CHANGE "monitor_focus_change_event"
#define IPC_EVENT_FOCUSED_TITLE_CHANGE "focused_title_change_event"
#define IPC_EVENT_FOCUSED_STATE_CHANGE "focused_state_change_event"

static void ipc_send(DwmIpc *dwm, DwmIpcMessage msg_type, uint8_t *msg, uint32_t msg_size)
{
    DwmIpcHeader header;
    memcpy(header.magic, IPC_MAGIC, IPC_MAGIC_LEN);
    header.size = msg_size;
    header.type = msg_type;

    GError *error = NULL;

    gssize size = 0;
    while (size < sizeof(DwmIpcHeader)) {
        gssize sent = g_socket_send(dwm->socket, (void *)&header + size, sizeof(DwmIpcHeader) - size, NULL, &error);
        if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK)) {
            g_error_free(error);
            continue;
        }
        g_assert(sent != -1);
        size += sent;
    }

    size = 0;
    while (size < msg_size) {
        gssize sent = g_socket_send(dwm->socket, msg + size, msg_size - size, NULL, &error);
        if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK)) {
            g_error_free(error);
            continue;
        }
        g_assert(sent != -1);
        size += sent;
    }

    log_debug("Sent ipc message [type=%d, size=%d]", msg_type, msg_size);
}

static void ipc_subscribe(DwmIpc *dwm, const char *event)
{
    // {
    //   "event": "<event>",
    //   "action": "subscribe"
    // }

    JsonBuilder *builder = json_builder_new();

    json_builder_begin_object(builder);

    json_builder_set_member_name(builder, "event");
    json_builder_add_string_value(builder, event);

    json_builder_set_member_name(builder, "action");
    json_builder_add_string_value(builder, "subscribe");

    json_builder_end_object(builder);

    JsonNode *root = json_builder_get_root(builder);

    JsonGenerator *gen = json_generator_new();
    json_generator_set_root(gen, root);

    gsize msg_len = 0;
    gchar *msg = json_generator_to_data(gen, &msg_len);

    log_debug("Subscribing to dwm ipc: %s", msg);
    ipc_send(dwm, IPC_TYPE_SUBSCRIBE, msg, msg_len);

    json_node_free(root);
    g_object_unref(gen);
    g_object_unref(builder);
    g_free(msg);
}

static void ipc_run_command(DwmIpc *dwm, const char *cmd, JsonNode **args)
{
    // {
    //   "command": "<name>",
    //   "args": [ ... ]
    // }

    JsonBuilder *builder = json_builder_new();

    json_builder_begin_object(builder);

    json_builder_set_member_name(builder, "command");
    json_builder_add_string_value(builder, cmd);

    json_builder_set_member_name(builder, "args");
    json_builder_begin_array(builder);

    while (*args != NULL) {
        json_builder_add_value(builder, *args++);
    }

    json_builder_end_array(builder);
    json_builder_end_object(builder);

    JsonNode *root = json_builder_get_root(builder);

    JsonGenerator *gen = json_generator_new();
    json_generator_set_root(gen, root);

    gsize msg_len = 0;
    gchar *msg = json_generator_to_data(gen, &msg_len);

    log_debug("Sending command to dwm ipc: %s", msg);
    ipc_send(dwm, IPC_TYPE_RUN_COMMAND, msg, msg_len);

    json_node_free(root);
    g_object_unref(gen);
    g_object_unref(builder);
    g_free(msg);
}

#define JSON_FIELD(reader, member) (json_reader_end_member(reader), json_reader_read_member(reader, member))

static void ipc_handle(DwmIpc *dwm, DwmIpcMessage type, char *reply, uint32_t reply_size)
{
    GError *error = NULL;
    JsonParser *parser = json_parser_new();
    if (!json_parser_load_from_data(parser, reply, reply_size - 1, &error)) {
        log_warning("Failed to parse dwm ipc reply: %s", error->message);
        g_error_free(error);
        return;
    }

    JsonReader *reader = json_reader_new(json_parser_get_root(parser));

    if (type == IPC_TYPE_EVENT) {
        if (json_reader_read_member(reader, IPC_EVENT_TAG_CHANGE)) {
            log_debug("Handling dwm ipc event [event=%s]", IPC_EVENT_TAG_CHANGE);

            json_reader_read_member(reader, "new_state");
            json_reader_read_member(reader, "selected");
            long selected = json_reader_get_int_value(reader);
            json_reader_end_member(reader);
            json_reader_end_member(reader);
            json_reader_end_member(reader);

            log_debug("Selected tag mask: %ld", selected);

            if (dwm->tags[0] != NULL) {
                for (int i = 0; i < 9; i++)
                    dwm->tags[i]->color = selected & (1 << i) ? dwm->selected : dwm->color;

                state_redraw(dwm->state, false);
            }
        } else if (JSON_FIELD(reader, IPC_EVENT_CLIENT_FOCUS_CHANGE)) {
            log_debug("Handling dwm ipc event [event=%s]", IPC_EVENT_CLIENT_FOCUS_CHANGE);

            json_reader_read_member(reader, "new_win_id");
            long win_id = json_reader_get_int_value(reader);
            json_reader_end_member(reader);
            json_reader_end_member(reader);

            char *msg = g_strdup_printf("{ \"client_window_id\": %ld }\n", win_id);
            dwm->change_title = true;
            ipc_send(dwm, IPC_TYPE_GET_DWM_CLIENT, msg, strlen(msg));
            g_free(msg);
        } else if (JSON_FIELD(reader, IPC_EVENT_LAYOUT_CHANGE)) {
            log_debug("Ignoring dwm ipc event [event=%s]", IPC_EVENT_LAYOUT_CHANGE);
            // TODO

        } else if (JSON_FIELD(reader, IPC_EVENT_MONITOR_FOCUS_CHANGE)) {
            log_debug("Ignoring dwm ipc event [event=%s]", IPC_EVENT_MONITOR_FOCUS_CHANGE);
            // TODO

        } else if (JSON_FIELD(reader, IPC_EVENT_FOCUSED_TITLE_CHANGE)) {
            log_debug("Ignoring dwm ipc event [event=%s]", IPC_EVENT_FOCUSED_TITLE_CHANGE);
            // TODO

        } else if (JSON_FIELD(reader, IPC_EVENT_FOCUSED_STATE_CHANGE)) {
            log_debug("Ignoring dwm ipc event [event=%s]", IPC_EVENT_FOCUSED_STATE_CHANGE);
            // TODO

        } else {
            const char *event = "?";
            if (json_reader_read_element(reader, 0))
                event = json_reader_get_string_value(reader);

            log_warning("Unrecognized dwm ipc event: %s", event);
        }
    } else if (type == IPC_TYPE_GET_DWM_CLIENT) {
        log_debug("Received dwm client information message [type=%d]", type);

        if (dwm->change_title) {
            json_reader_read_member(reader, "name");
            const char *title = json_reader_get_string_value(reader);

            log_debug("Changing current program title: %s", title ? title : "?");
            if (title == NULL || strlen(title) == 0) {
                state_remove_button(dwm->state, dwm->title);
                dwm->hidden_title = true;
            } else {
                button_simple_set_text(dwm->title, g_strdup(title), dwm->text_color);
                if (dwm->hidden_title) {
                    state_add_button(dwm->state, dwm->title);
                    dwm->hidden_title = false;
                }
            }

            dwm->change_title = false;
            state_redraw(dwm->state, true);
            json_reader_end_member(reader);
        }
    } else {
        log_debug("Ignoring dwm ipc message [type=%d]", type);
        //log_debug("%s", reply);
    }

    g_object_unref(reader);
    g_object_unref(parser);
}

static gboolean socket_callback(GSocket *socket, GIOCondition condition, gpointer data)
{
    if (condition & (G_IO_ERR | G_IO_HUP | G_IO_NVAL)) return G_SOURCE_REMOVE;
    GError *error = NULL;

    DwmIpcHeader header;
    gssize size = 0;
    while (size < sizeof(DwmIpcHeader)) {
        gssize read = g_socket_receive(socket, (void *)&header + size, sizeof(DwmIpcHeader) - size, NULL, &error);
        if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK)) {
            g_error_free(error);
            continue;
        }
        g_assert(read != -1);
        size += read;
    }

    if (memcmp(&header, IPC_MAGIC, IPC_MAGIC_LEN) != 0) {
        log_warning("Malformed dwm ipc message");
        return G_SOURCE_CONTINUE;;
    }

    uint32_t reply_size;
    memcpy(&reply_size, (void *)&header + IPC_MAGIC_LEN, sizeof(uint32_t));

    uint8_t msg_type;
    memcpy(&msg_type, (void *)&header + IPC_MAGIC_LEN + sizeof(uint32_t), sizeof(uint8_t));

    char *reply = g_malloc(reply_size);
    size = 0;
    while (size < reply_size) {
        gssize read = g_socket_receive(socket, reply + size, reply_size - size, NULL, NULL);
        if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK)) {
            g_error_free(error);
            continue;
        }
        g_assert(read != -1);
        size += read;
    }

    //log_debug("Received dwm ipc response: %s", reply);
    ipc_handle(data, msg_type, reply, reply_size);

    return G_SOURCE_CONTINUE;
}

DwmIpc *dwm_create(State *state, const char *socket)
{
    DwmIpc *dwm = g_malloc0(sizeof(DwmIpc));
    dwm->state = state;

    GError *error = NULL;
    dwm->socket = g_socket_new(G_SOCKET_FAMILY_UNIX, G_SOCKET_TYPE_STREAM, 0, &error);
    g_assert_nonnull(dwm->socket);

    GSocketAddress *addr = g_unix_socket_address_new(socket);
    if (!g_socket_connect(dwm->socket, addr, NULL, &error)) {
        g_assert_nonnull(error);
        log_debug("Failed to connect socket %s: %s", socket, error->message);
        log_info("Skipped dwm ipc [socket=%s]", socket);

        g_error_free(error);
        g_object_unref(dwm->socket);
        g_free(dwm);
        return NULL;
    }

    dwm->source = g_socket_create_source(dwm->socket, G_IO_IN, NULL);
    g_source_set_static_name(dwm->source, "DwmIpcSource");
    g_source_set_callback(dwm->source, (GSourceFunc)socket_callback, dwm, NULL);

    const char *events[] = {
        IPC_EVENT_TAG_CHANGE,
        IPC_EVENT_CLIENT_FOCUS_CHANGE,
        IPC_EVENT_LAYOUT_CHANGE,
        IPC_EVENT_MONITOR_FOCUS_CHANGE,
        IPC_EVENT_FOCUSED_TITLE_CHANGE,
        IPC_EVENT_FOCUSED_STATE_CHANGE,
    };
    for (int i = 0; i < G_N_ELEMENTS(events); ++i)
        ipc_subscribe(dwm, events[i]);

    g_source_attach(dwm->source, NULL);
    log_info("Attached dwm ipc source [socket=%s]", socket);

    return dwm;
}

static void change_tag_action(Button *btn)
{
    ButtonSimple *sbtn = CAST(btn, ButtonSimple);
    DwmIpc *dwm = sbtn->action_data;

    int n = sbtn->text[0] - '0';
    g_assert(n >= 1 && n <= 9);

    log_info("Toggled tag %d", n);

    JsonNode *args[] = {
        json_node_init_int(json_node_alloc(), 1 << (n - 1)),
        NULL
    };
    ipc_run_command(dwm, "view", args);
}

void dwm_register_tags(DwmIpc *dwm, Color color, Color selected, Color text_color, Color line_color)
{
    if (dwm == NULL) return;

    dwm->color = color;
    dwm->text_color = text_color;
    dwm->selected = selected;

    // Tags button
    for (int i = 0; i < 9; ++i) {
        char text[] = { '1' + i, '\0' };
        dwm->tags[i] = button_simple_create(PANGO_ALIGN_LEFT, color, line_color);
        button_simple_set_text(dwm->tags[i], g_strdup(text), text_color);
        button_simple_set_action(dwm->tags[i], change_tag_action, dwm);
        state_add_button(dwm->state, dwm->tags[i]);
    }

    dwm->title = button_simple_create(PANGO_ALIGN_CENTER, color, line_color);
    dwm->hidden_title = true;
}

void dwm_destroy(DwmIpc *dwm)
{
    if (dwm == NULL) return;

    g_source_destroy(dwm->source);
    g_source_unref(dwm->source);
    g_object_unref(dwm->socket);
    g_free(dwm);
}

// vim: ts=4 sw=4 et