#include "internal.h"

#define IME_TEXT_MAX (256u * 1024)

static void show_preedit(struct wayland_surface *w, char *text, int begin, int end)
{
    bool changed = (text || w->ime_shown) &&
                   (!text || !w->ime_shown || strcmp(text, w->ime_shown) ||
                    begin != w->ime_shown_begin || end != w->ime_shown_end);
    free(w->ime_shown);
    w->ime_shown = text;
    w->ime_shown_begin = begin;
    w->ime_shown_end = end;
    if (changed)
        wayland_surface_schedule_redraw(w);
}

void ime_reset(struct wayland_surface *w)
{
    free(w->ime_preedit);
    w->ime_preedit = NULL;
    free(w->ime_commit);
    w->ime_commit = NULL;
    show_preedit(w, NULL, -1, -1);
}

void ime_send_caret(struct wayland_surface *w)
{
    struct seat *seat = w->ime_seat;
    if (!seat || !seat->text_input)
        return;
    uint32_t scale = w->scale_120 ? w->scale_120 : YASL_SCALE_UNIT;
    zwp_text_input_v3_set_cursor_rectangle(seat->text_input,
            yasl_scale_to_logical(w->ime_caret.x, scale),
            yasl_scale_to_logical(w->ime_caret.y, scale),
            yasl_scale_to_logical(w->ime_caret.width, scale),
            yasl_scale_to_logical(w->ime_caret.height, scale));
    zwp_text_input_v3_commit(seat->text_input);
}

bool wayland_surface_ime_preedit_cursor(const struct wayland_surface *w, int *begin, int *end)
{
    if (!w || !w->ime_shown || w->ime_shown_begin < 0)
        return false;
    *begin = w->ime_shown_begin;
    *end = w->ime_shown_end;
    return true;
}

void wayland_surface_set_ime_caret(struct wayland_surface *w, struct yasl_rect2i caret)
{
    if (!w || (w->ime_caret.x == caret.x && w->ime_caret.y == caret.y &&
               w->ime_caret.width == caret.width && w->ime_caret.height == caret.height))
        return;
    w->ime_caret = caret;
    ime_send_caret(w);
}

static void text_input_enter(void *data, struct zwp_text_input_v3 *text_input,
                             struct wl_surface *surface)
{
    struct seat *s = data;
    struct wayland_surface *w = surface_root(surface ?
        (struct wayland_surface *)wl_surface_get_user_data(surface) : NULL);
    s->ime_focus = w;
    if (!w) return;
    zwp_text_input_v3_enable(text_input);
    zwp_text_input_v3_set_content_type(text_input,
            ZWP_TEXT_INPUT_V3_CONTENT_HINT_NONE,
            ZWP_TEXT_INPUT_V3_CONTENT_PURPOSE_TERMINAL);
    w->ime_seat = s;
    ime_send_caret(w);
}

static void text_input_leave(void *data, struct zwp_text_input_v3 *text_input,
                             struct wl_surface *surface)
{
    (void)surface;
    struct seat *s = data;
    struct wayland_surface *w = s->ime_focus;
    s->ime_focus = NULL;
    if (!w) return;
    zwp_text_input_v3_disable(text_input);
    zwp_text_input_v3_commit(text_input);
    if (w->ime_seat == s)
        w->ime_seat = NULL;
    ime_reset(w);
}

static void text_input_preedit_string(void *data,
        struct zwp_text_input_v3 *text_input, const char *text,
        int32_t cursor_begin, int32_t cursor_end)
{
    (void)text_input;
    struct wayland_surface *w = ((struct seat *)data)->ime_focus;
    if (!w) return;
    keyboard_text_reset((struct seat *)data);
    free(w->ime_preedit);
    w->ime_preedit = text ? strndup(text, IME_TEXT_MAX) : NULL;
    int len = w->ime_preedit ? (int)strlen(w->ime_preedit) : 0;
    bool shown = cursor_begin >= 0 && cursor_end >= cursor_begin &&
                 cursor_end <= len;
    w->ime_cursor_begin = shown ? cursor_begin : -1;
    w->ime_cursor_end = shown ? cursor_end : -1;
}

static void text_input_commit_string(void *data,
        struct zwp_text_input_v3 *text_input, const char *text)
{
    (void)text_input;
    struct wayland_surface *w = ((struct seat *)data)->ime_focus;
    if (!w) return;
    keyboard_text_reset((struct seat *)data);
    free(w->ime_commit);
    w->ime_commit = (text && text[0]) ? strndup(text, IME_TEXT_MAX) : NULL;
}

static void text_input_delete_surrounding_text(void *data,
        struct zwp_text_input_v3 *text_input, uint32_t before_length,
        uint32_t after_length)
{
    (void)data; (void)text_input; (void)before_length; (void)after_length;
}

static void text_input_done(void *data, struct zwp_text_input_v3 *text_input,
                            uint32_t serial)
{
    (void)text_input; (void)serial;
    struct wayland_surface *w = ((struct seat *)data)->ime_focus;
    if (!w) return;
    if (w->ime_commit) {
        struct yasl_event ev = {
            .type = YASL_EVENT_TEXT,
            .surface = &w->base,
            .text = { .data = w->ime_commit, .len = strlen(w->ime_commit) },
        };
        input_queue_push(&w->input, &ev);
        free(w->ime_commit);
        w->ime_commit = NULL;
    }
    char *preedit = w->ime_preedit && w->ime_preedit[0] ? w->ime_preedit : NULL;
    if (!preedit)
        free(w->ime_preedit);
    w->ime_preedit = NULL;
    show_preedit(w, preedit, preedit ? w->ime_cursor_begin : -1,
                 preedit ? w->ime_cursor_end : -1);
    w->ime_cursor_begin = w->ime_cursor_end = -1;
}

static void text_input_action(void *data, struct zwp_text_input_v3 *text_input,
        uint32_t action, uint32_t serial)
{ (void)data; (void)text_input; (void)action; (void)serial; }

static void text_input_language(void *data, struct zwp_text_input_v3 *text_input,
        const char *language)
{ (void)data; (void)text_input; (void)language; }

static void text_input_preedit_hint(void *data, struct zwp_text_input_v3 *text_input,
        uint32_t start, uint32_t end, uint32_t hint)
{ (void)data; (void)text_input; (void)start; (void)end; (void)hint; }

const struct zwp_text_input_v3_listener text_input_listener = {
    .action = text_input_action,
    .language = text_input_language,
    .preedit_hint = text_input_preedit_hint,
    .enter = text_input_enter,
    .leave = text_input_leave,
    .preedit_string = text_input_preedit_string,
    .commit_string = text_input_commit_string,
    .delete_surrounding_text = text_input_delete_surrounding_text,
    .done = text_input_done,
};