#include "ecex.h"

#define RENDER_DEMO_BUF "*render-demo*"
#define RENDER_DEMO_VAR_X "x_milli"
#define RENDER_DEMO_VAR_Y "y_milli"
#define RENDER_DEMO_VAR_TARGET_X "target_x_milli"
#define RENDER_DEMO_VAR_TARGET_Y "target_y_milli"
#define RENDER_DEMO_VAR_MOVING "moving"
#define RENDER_DEMO_VAR_BOX_X "box_x"
#define RENDER_DEMO_VAR_BOX_Y "box_y"
#define RENDER_DEMO_VAR_BOX_SIZE "box_size"
#define RENDER_DEMO_VAR_TRAVEL_X "travel_x"
#define RENDER_DEMO_VAR_TRAVEL_Y "travel_y"
#define RENDER_DEMO_VAR_AREA_X "area_x"
#define RENDER_DEMO_VAR_AREA_Y "area_y"

#define RENDER_DEMO_LABEL_TITLE 20
#define RENDER_DEMO_LABEL_SUBTITLE 21
#define RENDER_DEMO_LABEL_SAFE_DRAW 22
#define RENDER_DEMO_LABEL_ANIM 23
#define RENDER_DEMO_LABEL_POSITION 24
#define RENDER_DEMO_LABEL_CLICK 25

typedef struct render_demo_state {
    ecex_t *ed;
    int log_draw_count;
} render_demo_state_t;

static int render_demo_get(ecex_t *ed, render_demo_state_t *s, const char *name, int fallback) {
    if (!ed || !s || !name) return fallback;
    return ecex_var_i32(ed, s, name, fallback);
}

static void render_demo_set(ecex_t *ed, render_demo_state_t *s, const char *name, int value) {
    if (!ed || !s || !name) return;
    ecex_var_i32_set_scalar(ed, s, name, value);
}

static void render_demo_reset(ecex_t *ed, render_demo_state_t *s) {
    ecex_log_ptr("render_demo_reset: state=", s);
    if (!ed || !s) return;

    /* Store mutable demo state in the host variable registry. This mirrors the
     * Tetris plugin flow and avoids relying on CCDJIT struct-field writes for
     * values that must survive renderer, animation, and mouse callbacks.
     * Values are fixed-point integers: 0..1000 represents the available travel
     * range inside the demo frame. */
    render_demo_set(ed, s, RENDER_DEMO_VAR_X, 0);
    render_demo_set(ed, s, RENDER_DEMO_VAR_Y, 500);
    render_demo_set(ed, s, RENDER_DEMO_VAR_TARGET_X, 0);
    render_demo_set(ed, s, RENDER_DEMO_VAR_TARGET_Y, 500);
    render_demo_set(ed, s, RENDER_DEMO_VAR_MOVING, 0);
    s->log_draw_count = 0;
}

static int render_demo_draw(ecex_t *ed, buffer_t *buffer, ecex_draw_context_t *ctx, void *userdata) {
    render_demo_state_t *s = (render_demo_state_t *)userdata;
    int w;
    int h;
    int cx;
    int cy;
    int cw;
    int ch;
    int line_h;
    int box;
    int travel;
    int x_milli;
    int y_milli;
    int box_x;
    int box_y;
    int travel_y;
    int area_x;
    int area_y;

    (void)buffer;
    if (!ed || !ctx || !s) return 0;

    s->log_draw_count++;
    if (s->log_draw_count <= 4 || (s->log_draw_count % 60) == 0) {
        ecex_log_int("render_demo_draw: count=", s->log_draw_count);
    }

    w = (int)ctx->w;
    h = (int)ctx->h;
    cx = (int)ctx->content_x;
    cy = (int)ctx->content_y;
    cw = (int)ctx->content_w;
    ch = (int)ctx->content_h;
    line_h = (int)ctx->line_height;
    if (line_h < 18) line_h = 18;
    if (cw < 1) cw = w - cx * 2;
    if (ch < 1) ch = h - cy * 2;
    if (cw < 1) cw = 1;
    if (ch < 1) ch = 1;

    ecex_draw_color_rgba8(ctx, 26, 28, 36, 255);
    ecex_draw_rect_i(ctx, 0, 0, w, h);

    ecex_draw_color_rgba8(ctx, 48, 96, 180, 255);
    ecex_draw_rect_i(ctx, cx, cy, (cw * 55) / 100, line_h * 2);

    ecex_draw_color_rgba8(ctx, 242, 230, 191, 255);
    ecex_draw_rect_outline_i(ctx, cx, cy, cw, ch, 2);
    ecex_draw_label_i(ctx, cx + 12, cy + 10, RENDER_DEMO_LABEL_TITLE);

    ecex_draw_color_rgba8(ctx, 229, 89, 64, 255);
    ecex_draw_line_i(ctx, cx, cy + ch, cx + cw, cy, 3);

    ecex_draw_color_rgba8(ctx, 160, 230, 180, 255);
    ecex_draw_label_i(ctx, cx + 12, cy + line_h * 3, RENDER_DEMO_LABEL_SUBTITLE);
    ecex_draw_label_i(ctx, cx + 12, cy + line_h * 4, RENDER_DEMO_LABEL_SAFE_DRAW);
    ecex_draw_label_i(ctx, cx + 12, cy + line_h * 5, RENDER_DEMO_LABEL_ANIM);
    ecex_draw_label_i(ctx, cx + 12, cy + line_h * 6, RENDER_DEMO_LABEL_CLICK);

    x_milli = render_demo_get(ed, s, RENDER_DEMO_VAR_X, 0);
    y_milli = render_demo_get(ed, s, RENDER_DEMO_VAR_Y, 500);
    ecex_draw_stat_i(ctx, cx + 12, cy + line_h * 8, RENDER_DEMO_LABEL_POSITION, x_milli);

    box = line_h * 2;
    if (box < 36) box = 36;
    if (box > 72) box = 72;
    travel = cw - box - 24;
    if (travel < 0) travel = 0;
    area_x = cx + 12;
    area_y = cy + line_h * 10;
    travel_y = ch - (area_y - cy) - box - 12;
    if (travel_y < 0) travel_y = 0;
    if (x_milli < 0) x_milli = 0;
    if (x_milli > 1000) x_milli = 1000;
    if (y_milli < 0) y_milli = 0;
    if (y_milli > 1000) y_milli = 1000;
    box_x = area_x + (travel * x_milli) / 1000;
    box_y = area_y + (travel_y * y_milli) / 1000;

    render_demo_set(ed, s, RENDER_DEMO_VAR_BOX_X, box_x);
    render_demo_set(ed, s, RENDER_DEMO_VAR_BOX_Y, box_y);
    render_demo_set(ed, s, RENDER_DEMO_VAR_BOX_SIZE, box);
    render_demo_set(ed, s, RENDER_DEMO_VAR_TRAVEL_X, travel);
    render_demo_set(ed, s, RENDER_DEMO_VAR_TRAVEL_Y, travel_y);
    render_demo_set(ed, s, RENDER_DEMO_VAR_AREA_X, area_x);
    render_demo_set(ed, s, RENDER_DEMO_VAR_AREA_Y, area_y);

    ecex_draw_color_rgba8(ctx, 70, 76, 90, 255);
    ecex_draw_rect_outline_i(ctx, area_x, area_y, travel + box, travel_y + box, 1);

    ecex_draw_color_rgba8(ctx, 89, 242, 140, 255);
    ecex_draw_rect_i(ctx, box_x, box_y, box, box);
    ecex_draw_color_rgba8(ctx, 20, 24, 30, 255);
    ecex_draw_rect_outline_i(ctx, box_x, box_y, box, box, 2);

    return 0;
}


static int render_demo_clamp_milli(int value) {
    if (value < 0) return 0;
    if (value > 1000) return 1000;
    return value;
}

static int render_demo_delta_step(int current, int target) {
    int delta = target - current;
    int step;
    if (delta < 0) {
        if (delta >= -4) return target;
        step = delta / 5;
        if (step == 0) step = -1;
        return current + step;
    }
    if (delta <= 4) return target;
    step = delta / 5;
    if (step == 0) step = 1;
    return current + step;
}

static int render_demo_tick(ecex_t *ed, buffer_t *buffer, int now_ms, void *userdata) {
    render_demo_state_t *s = (render_demo_state_t *)userdata;
    int x;
    int y;
    int target_x;
    int target_y;
    int next_x;
    int next_y;

    (void)buffer;
    (void)now_ms;
    if (!ed || !s) return 0;
    if (!render_demo_get(ed, s, RENDER_DEMO_VAR_MOVING, 0)) return 0;

    x = render_demo_get(ed, s, RENDER_DEMO_VAR_X, 0);
    y = render_demo_get(ed, s, RENDER_DEMO_VAR_Y, 500);
    target_x = render_demo_get(ed, s, RENDER_DEMO_VAR_TARGET_X, x);
    target_y = render_demo_get(ed, s, RENDER_DEMO_VAR_TARGET_Y, y);

    next_x = render_demo_delta_step(x, target_x);
    next_y = render_demo_delta_step(y, target_y);
    render_demo_set(ed, s, RENDER_DEMO_VAR_X, render_demo_clamp_milli(next_x));
    render_demo_set(ed, s, RENDER_DEMO_VAR_Y, render_demo_clamp_milli(next_y));

    if (next_x == target_x && next_y == target_y) {
        render_demo_set(ed, s, RENDER_DEMO_VAR_MOVING, 0);
        ecex_log("render_demo_tick: target reached");
    }
    return 1;
}

static int render_demo_mouse(ecex_t *ed, buffer_t *buffer, int event, int x, int y, int button, void *userdata) {
    render_demo_state_t *s = (render_demo_state_t *)userdata;
    int box;
    int area_x;
    int area_y;
    int travel_x;
    int travel_y;
    int nx;
    int ny;

    (void)buffer;
    if (!ed || !s || button != ECEX_MOUSE_BUTTON_LEFT) return 0;
    if (event != ECEX_MOUSE_PRESS) return 0;

    box = render_demo_get(ed, s, RENDER_DEMO_VAR_BOX_SIZE, 0);
    area_x = render_demo_get(ed, s, RENDER_DEMO_VAR_AREA_X, 0);
    area_y = render_demo_get(ed, s, RENDER_DEMO_VAR_AREA_Y, 0);
    travel_x = render_demo_get(ed, s, RENDER_DEMO_VAR_TRAVEL_X, 0);
    travel_y = render_demo_get(ed, s, RENDER_DEMO_VAR_TRAVEL_Y, 0);
    if (box <= 0) return 0;

    if (x < area_x || x >= area_x + travel_x + box ||
        y < area_y || y >= area_y + travel_y + box) {
        return 0;
    }

    nx = x - area_x - box / 2;
    ny = y - area_y - box / 2;
    if (travel_x <= 0) render_demo_set(ed, s, RENDER_DEMO_VAR_TARGET_X, 0);
    else render_demo_set(ed, s, RENDER_DEMO_VAR_TARGET_X, render_demo_clamp_milli((nx * 1000) / travel_x));
    if (travel_y <= 0) render_demo_set(ed, s, RENDER_DEMO_VAR_TARGET_Y, 0);
    else render_demo_set(ed, s, RENDER_DEMO_VAR_TARGET_Y, render_demo_clamp_milli((ny * 1000) / travel_y));

    render_demo_set(ed, s, RENDER_DEMO_VAR_MOVING, 1);
    ecex_log("render_demo_mouse: target set");
    return 1;
}

static void render_demo_free_state(void *userdata) {
    render_demo_state_t *s = (render_demo_state_t *)userdata;
    if (!s) return;
    ecex_var_free_owner(s->ed, s);
    ecex_config_free(s);
}

static int cmd_render_demo(ecex_t *ed) {
    buffer_t *buffer;
    render_demo_state_t *s;

    ecex_log("cmd_render_demo: enter");
    if (!ed) return -1;

    buffer = ecex_find_buffer(ed, RENDER_DEMO_BUF);
    if (!buffer) buffer = ecex_create_interactive_buffer(ed, RENDER_DEMO_BUF);
    if (!buffer) return -1;

    s = (render_demo_state_t *)ecex_buffer_renderer_userdata(buffer);
    if (!s) {
        s = (render_demo_state_t *)ecex_config_calloc(1, sizeof(*s));
        if (!s) return -1;
        s->ed = ed;
        render_demo_reset(ed, s);

        if (ecex_buffer_set_renderer(buffer, render_demo_draw, s, render_demo_free_state, ECEX_RENDER_REPLACE_CONTENT) != 0) {
            render_demo_free_state(s);
            return -1;
        }
        if (ecex_buffer_set_mouse_handler(buffer, render_demo_mouse, s, 0) != 0) {
            ecex_buffer_clear_renderer(buffer);
            return -1;
        }
        if (ecex_buffer_set_animation_ms(buffer, render_demo_tick, s, 0, 60) != 0) {
            ecex_buffer_clear_mouse_handler(buffer);
            ecex_buffer_clear_renderer(buffer);
            return -1;
        }
    }

    if (ecex_buffer_replace_text(buffer, "Render demo. The renderer replaces normal buffer content.\n") != 0) {
        return -1;
    }
    ecex_buffer_set_modified(buffer, 0);

    return ecex_switch_buffer(ed, RENDER_DEMO_BUF);
}

int ecex_render_demo_plugin(ecex_t *ed) {
    ECEX_CONFIG_COMMAND("render-demo", cmd_render_demo);
    return 0;
}

#ifndef ECEX_NO_STANDALONE_CONFIG
ECEX_CONFIG_BEGIN
    ECEX_CONFIG_INCLUDE(ecex_render_demo_plugin);
ECEX_CONFIG_END
#endif