#include "ecex.h"

#define MD_TEXT_TITLE 1

typedef struct md_state {
    ecex_plugin_t *plugin;
} md_state_t;

static int md_line_is_fence(const char *line) {
    const char *p = line;
    if (!p) return 0;
    while (*p == ' ' || *p == '\t') ++p;
    return p[0] == '`' && p[1] == '`' && p[2] == '`';
}

static int md_in_code_at_line(buffer_t *buffer, int line) {
    char scratch[256];
    int in_code = 0;
    int i;
    if (!buffer || line <= 0) return 0;
    for (i = 0; i < line; ++i) {
        if (ecex_buffer_line_copy_text(buffer, i, scratch, (int)sizeof(scratch)) < 0) continue;
        if (md_line_is_fence(scratch)) in_code = !in_code;
    }
    return in_code;
}

static int md_render(ecex_t *ed, buffer_t *buffer, ecex_draw_context_t *ctx, void *userdata) {
    md_state_t *state = (md_state_t *)userdata;
    int draw_count;
    int line_count;
    int scroll;
    int y;
    int h;
    int line_h;
    int in_code = 0;
    int i;

    if (!ed || !buffer || !ctx || !state) return 0;

    draw_count = ecex_plugin_slot_i32_get_scalar(state->plugin, "draw_count", 0) + 1;
    ecex_plugin_slot_i32_set_scalar(state->plugin, "draw_count", draw_count);
    if (draw_count <= 2 || (draw_count % 120) == 0) {
        ecex_log_int("markdown_plugin_draw: count=", draw_count);
    }

    line_count = ecex_buffer_line_count_int(buffer);
    ecex_log_int("markdown_plugin_draw: line_count=", line_count);
    if (line_count < 0) line_count = 0;

    ecex_plugin_text_set_from_buffer_title(state->plugin, MD_TEXT_TITLE, buffer);
    ecex_draw_markdown_canvas_auto_i(ctx, state->plugin, MD_TEXT_TITLE);

    y = ecex_markdown_body_y_px(ctx);
    h = ecex_draw_context_height_px(ctx);
    line_h = ecex_draw_context_line_height_px(ctx);
    scroll = ecex_buffer_scroll_line_index(buffer);
    if (scroll < 0) scroll = 0;
    if (scroll > line_count) scroll = line_count;
    in_code = md_in_code_at_line(buffer, scroll);

    for (i = scroll; i < line_count && y < h - line_h; ++i) {
        int packed;
        int advance;
        if (i < scroll + 4) ecex_log_int("markdown_plugin_draw: host line=", i);
        packed = ecex_markdown_draw_buffer_line_i(ctx, state->plugin, buffer, i, y, in_code);
        in_code = (packed & 0x10000) ? 1 : 0;
        advance = packed & 0xffff;
        if (advance <= 0) advance = line_h;
        y += advance;
    }

    return 0;
}

static void md_free_state(void *userdata) {
    md_state_t *state = (md_state_t *)userdata;
    if (!state) return;
    ecex_plugin_text_free_all(state->plugin);
    ecex_plugin_object_free(state->plugin, state);
}

static int md_view_buffer(ecex_t *ed, buffer_t *buffer) {
    md_state_t *state;
    if (!ed || !buffer) return -1;
    if (ecex_buffer_has_renderer(buffer)) ecex_buffer_clear_renderer(buffer);

    ecex_plugin_t *plugin = ecex_plugin_find(ed, "markdown");
    state = (md_state_t *)ecex_plugin_object_calloc(plugin, "state", 1, sizeof(*state));
    if (!state) return -1;
    state->plugin = plugin;

    if (ecex_buffer_set_renderer(buffer, md_render, state, md_free_state, ECEX_RENDER_REPLACE_CONTENT) != 0) {
        ecex_plugin_object_free(plugin, state);
        return -1;
    }
    ecex_buffer_set_major_mode_by_name(ed, buffer, "markdown-mode");
    return 0;
}

static int md_file_handler(ecex_t *ed, buffer_t *buffer) {
    if (!buffer) return -1;
    if (ecex_buffer_has_renderer(buffer)) return 0;
    return md_view_buffer(ed, buffer);
}

static int cmd_markdown_view(ecex_t *ed) {
    return md_view_buffer(ed, ecex_current_buffer(ed));
}

static int cmd_markdown_source(ecex_t *ed) {
    buffer_t *buffer = ecex_current_buffer(ed);
    if (!buffer) return -1;
    if (ecex_buffer_has_renderer(buffer)) ecex_buffer_clear_renderer(buffer);
    ecex_buffer_set_major_mode_by_name(ed, buffer, "markdown-mode");
    return 0;
}

static int cmd_markdown_toggle(ecex_t *ed) {
    buffer_t *buffer = ecex_current_buffer(ed);
    if (!buffer) return -1;
    if (ecex_buffer_has_renderer(buffer)) return cmd_markdown_source(ed);
    return md_view_buffer(ed, buffer);
}

ECEX_PLUGIN_BEGIN(ecex_markdown_plugin, "markdown")
    ECEX_CONFIG_MODE("markdown-mode");
    ECEX_CONFIG_COMMAND("markdown-view", cmd_markdown_view);
    ECEX_CONFIG_COMMAND("markdown-source", cmd_markdown_source);
    ECEX_CONFIG_COMMAND("markdown-toggle", cmd_markdown_toggle);
    ECEX_CONFIG_MODE_BIND("markdown-mode", "C-c C-c", "markdown-toggle");
    ECEX_CONFIG_MODE_BIND("markdown-mode", "C-c C-s", "markdown-source");
    ECEX_CONFIG_TRY(ecex_plugin_file_handler_register(plugin, ".md", md_file_handler));
    ECEX_CONFIG_TRY(ecex_plugin_file_handler_register(plugin, ".markdown", md_file_handler));
    ECEX_CONFIG_TRY(ecex_plugin_file_handler_register(plugin, ".mdown", md_file_handler));
    ECEX_CONFIG_TRY(ecex_plugin_file_handler_register(plugin, ".mkd", md_file_handler));
    return 0;
ECEX_PLUGIN_END

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