#include "media.h"

#include "buffers.h"
#include "common.h"
#include "ecex.h"
#include "path.h"
#include "util.h"

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

extern FILE *popen(const char *command, const char *type);
extern int pclose(FILE *stream);
extern int mkstemp(char *template);

static char *shell_quote(const char *path) {
    if (!path) return NULL;
    size_t len = 2; /* quotes */
    for (const char *p = path; *p; p++) len += (*p == '\'') ? 4 : 1;
    char *out = malloc(len + 1);
    if (!out) return NULL;
    char *w = out;
    *w++ = '\'';
    for (const char *p = path; *p; p++) {
        if (*p == '\'') {
            memcpy(w, "'\\''", 4);
            w += 4;
        } else {
            *w++ = *p;
        }
    }
    *w++ = '\'';
    *w = '\0';
    return out;
}

static int ppm_skip_ws_and_comments(FILE *f) {
    int c = 0;
    do {
        c = fgetc(f);
        if (c == '#') {
            while (c != '\n' && c != EOF) c = fgetc(f);
        }
    } while (c != EOF && isspace((unsigned char)c));
    if (c == EOF) return EOF;
    ungetc(c, f);
    return 0;
}

static int ppm_read_int(FILE *f, int *out) {
    if (!f || !out) return ECEX_ERR;
    if (ppm_skip_ws_and_comments(f) == EOF) return ECEX_ERR;
    int c = fgetc(f);
    if (c == EOF || !isdigit((unsigned char)c)) return ECEX_ERR;
    int value = 0;
    while (c != EOF && isdigit((unsigned char)c)) {
        value = value * 10 + (c - '0');
        c = fgetc(f);
    }
    if (c != EOF) ungetc(c, f);
    *out = value;
    return ECEX_OK;
}

static int read_ppm_frame(FILE *f, int *out_w, int *out_h, unsigned char **out_rgba) {
    if (!f || !out_w || !out_h || !out_rgba) return ECEX_ERR;
    int p = fgetc(f);
    int six = fgetc(f);
    if (p == EOF || six == EOF) return ECEX_ERR;
    if (p != 'P' || six != '6') return ECEX_ERR;

    int w = 0, h = 0, maxv = 0;
    if (ppm_read_int(f, &w) != ECEX_OK || ppm_read_int(f, &h) != ECEX_OK || ppm_read_int(f, &maxv) != ECEX_OK) {
        return ECEX_ERR;
    }
    if (w <= 0 || h <= 0 || maxv <= 0 || maxv > 255) return ECEX_ERR;

    int c = fgetc(f);
    if (c == EOF) return ECEX_ERR;
    if (!isspace((unsigned char)c)) ungetc(c, f);

    size_t rgb_len = (size_t)w * (size_t)h * 3u;
    size_t rgba_len = (size_t)w * (size_t)h * 4u;
    if (w > 8192 || h > 8192 || rgb_len / 3u != (size_t)w * (size_t)h) return ECEX_ERR;

    unsigned char *rgb = malloc(rgb_len);
    unsigned char *rgba = malloc(rgba_len);
    if (!rgb || !rgba) {
        free(rgb);
        free(rgba);
        return ECEX_ERR;
    }

    size_t got = fread(rgb, 1, rgb_len, f);
    if (got != rgb_len) {
        free(rgb);
        free(rgba);
        return ECEX_ERR;
    }

    for (size_t i = 0, j = 0; i < rgb_len; i += 3, j += 4) {
        rgba[j + 0] = rgb[i + 0];
        rgba[j + 1] = rgb[i + 1];
        rgba[j + 2] = rgb[i + 2];
        rgba[j + 3] = 255;
    }

    free(rgb);
    *out_w = w;
    *out_h = h;
    *out_rgba = rgba;
    return ECEX_OK;
}

static int set_buffer_pixels(buffer_t *buffer, int w, int h, unsigned char *rgba) {
    if (!buffer || w <= 0 || h <= 0 || !rgba) {
        free(rgba);
        return ECEX_ERR;
    }
    free(buffer->media_pixels);
    buffer->media_pixels = rgba;
    buffer->media_width = w;
    buffer->media_height = h;
    buffer->media_dirty = 1;
    return ECEX_OK;
}

static char *make_temp_log_path(void) {
    char tmpl[] = "/tmp/ecex-ffmpeg-XXXXXX";
    int fd = mkstemp(tmpl);
    if (fd < 0) return NULL;
    close(fd);
    return ecex_strdup(tmpl);
}

static char *read_decode_log_status(const char *log_path, const char *fallback) {
    FILE *f = log_path ? fopen(log_path, "rb") : NULL;
    if (!f) return ecex_strdup(fallback ? fallback : "ffmpeg did not decode a preview frame.");

    char body[1400];
    size_t n = fread(body, 1, sizeof(body) - 1, f);
    fclose(f);
    body[n] = '\0';

    if (n == 0) return ecex_strdup(fallback ? fallback : "ffmpeg did not decode a preview frame.");

    char *out = malloc(n + 128);
    if (!out) return ecex_strdup(fallback ? fallback : "ffmpeg did not decode a preview frame.");
    snprintf(out, n + 128, "ffmpeg did not decode a preview frame.\n\nffmpeg stderr:\n%s", body);
    return out;
}

static char *make_decode_command(const char *path, int video, char **out_log_path) {
    char *q = shell_quote(path);
    if (!q) return NULL;
    char *log_path = make_temp_log_path();
    char *qlog = log_path ? shell_quote(log_path) : NULL;
    const char *ffmpeg = getenv("ECEX_FFMPEG");
    if (!ffmpeg || !*ffmpeg) ffmpeg = "ffmpeg";
    /*
     * Important: ffmpeg's filtergraph parser treats ',' as a filter
     * separator unless it is escaped, even when the expression is inside
     * quotes.  The previous command used min(%d,iw), which makes many
     * ffmpeg builds fail before producing a single PPM frame.  Keep the
     * comma escaped in the command string that reaches ffmpeg.
     *
     * -nostdin also prevents ffmpeg from accidentally consuming editor
     * terminal input when ecex is launched from a shell.
     */
    const char *fmt = video
        ? "%s -nostdin -hide_banner -loglevel error -i %s -an -vf \"fps=60,scale='min(%d\\,iw)':-2\" -f image2pipe -vcodec ppm - %s%s"
        : "%s -nostdin -hide_banner -loglevel error -i %s -frames:v 1 -vf \"scale='min(%d\\,iw)':-2\" -f image2pipe -vcodec ppm - %s%s";
    int need = snprintf(NULL,
                        0,
                        fmt,
                        ffmpeg,
                        q,
                        ECEX_MEDIA_MAX_DIMENSION,
                        qlog ? "2>" : "",
                        qlog ? qlog : "");
    char *cmd = malloc((size_t)need + 1);
    if (cmd) {
        snprintf(cmd,
                 (size_t)need + 1,
                 fmt,
                 ffmpeg,
                 q,
                 ECEX_MEDIA_MAX_DIMENSION,
                 qlog ? "2>" : "",
                 qlog ? qlog : "");
    }
    if (out_log_path) {
        *out_log_path = log_path;
        log_path = NULL;
    }
    free(qlog);
    free(log_path);
    free(q);
    return cmd;
}

static void buffer_set_media_text(buffer_t *buffer, const char *path, int video, const char *status) {
    if (!buffer) return;
    buffer->read_only = 0;
    buffer_clear(buffer);
    char text[2048];
    snprintf(text,
             sizeof(text),
             "%s preview: %s\n\n%s\n\nRequirements:\n  install ffmpeg/ffprobe in PATH for broad image and video decoding.\n\nControls:\n  Space / p  play-pause video\n  q          quit window\n",
             video ? "Video" : "Image",
             path ? path : "(unknown)",
             status ? status : "No decoded frame available.");
    buffer_append(buffer, text);
    buffer->modified = 0;
    buffer->read_only = 1;
}

void ecex_media_buffer_clear(buffer_t *buffer) {
    if (!buffer) return;
    if (buffer->media_pipe) {
        pclose((FILE *)buffer->media_pipe);
        buffer->media_pipe = NULL;
    }
    free(buffer->media_path);
    buffer->media_path = NULL;
    free(buffer->media_pixels);
    buffer->media_pixels = NULL;
    buffer->media_kind = ECEX_MEDIA_NONE;
    buffer->media_width = 0;
    buffer->media_height = 0;
    buffer->media_dirty = 0;
    buffer->media_texture_width = 0;
    buffer->media_texture_height = 0;
    buffer->media_last_frame_time = 0.0;
    buffer->media_playing = 0;
    buffer->media_status[0] = '\0';
}

int ecex_media_buffer_has_pixels(buffer_t *buffer) {
    return buffer && buffer->media_pixels && buffer->media_width > 0 && buffer->media_height > 0;
}

static buffer_t *media_buffer_for_path(ecex_t *ed, const char *path, int video) {
    if (!ed || !path) return NULL;
    char *base = ecex_path_basename_dup(path);
    if (!base) return NULL;
    char name[1024];
    snprintf(name, sizeof(name), "*%s-preview:%s*", video ? "video" : "image", base);
    free(base);

    buffer_t *buffer = ecex_find_buffer(ed, name);
    if (!buffer) buffer = ecex_create_buffer(ed, name, path, 1);
    if (!buffer) return NULL;
    return buffer;
}

int ecex_media_load_into_buffer(ecex_t *ed, const char *path, buffer_t *buffer) {
    if (!ed || !path || !buffer || !ecex_path_is_media(path)) return ECEX_ERR;
    int video = ecex_path_is_video(path);

    ecex_media_buffer_clear(buffer);
    buffer->media_kind = video ? ECEX_MEDIA_VIDEO : ECEX_MEDIA_IMAGE;
    ecex_buffer_set_major_mode_by_name(ed, buffer, "media-preview-mode");
    buffer->media_path = ecex_path_normalize(path);
    if (!buffer->media_path) buffer->media_path = ecex_strdup(path);
    buffer->read_only = 0;
    buffer_clear(buffer);
    buffer_append(buffer, video ? "Loading video preview...\n" : "Loading image preview...\n");
    buffer->modified = 0;
    buffer->read_only = 1;

    char *log_path = NULL;
    char *cmd = make_decode_command(buffer->media_path ? buffer->media_path : path, video, &log_path);
    if (!cmd) {
        buffer_set_media_text(buffer, path, video, "Could not allocate ffmpeg command.");
        free(log_path);
        return ECEX_ERR;
    }

    FILE *pipe = popen(cmd, "r");
    free(cmd);
    if (!pipe) {
        buffer_set_media_text(buffer, path, video, "Could not launch ffmpeg.");
        if (log_path) unlink(log_path);
        free(log_path);
        return ECEX_ERR;
    }

    int w = 0, h = 0;
    unsigned char *rgba = NULL;
    if (read_ppm_frame(pipe, &w, &h, &rgba) != ECEX_OK) {
        pclose(pipe);
        char *status = read_decode_log_status(log_path, "ffmpeg did not decode a preview frame.");
        buffer_set_media_text(buffer, path, video, status);
        free(status);
        if (log_path) unlink(log_path);
        free(log_path);
        return ECEX_ERR;
    }

    if (log_path) unlink(log_path);
    free(log_path);

    if (video) {
        buffer->media_pipe = pipe;
        buffer->media_playing = 1;
        snprintf(buffer->media_status, sizeof(buffer->media_status), "Playing at decoded 60fps stream");
    } else {
        pclose(pipe);
        snprintf(buffer->media_status, sizeof(buffer->media_status), "Image decoded via ffmpeg");
    }

    set_buffer_pixels(buffer, w, h, rgba);
    buffer->read_only = 0;
    buffer_clear(buffer);
    char info[1024];
    snprintf(info,
             sizeof(info),
             "%s preview: %s\n%d x %d\n%s\n\n%s\n",
             video ? "Video" : "Image",
             buffer->media_path ? buffer->media_path : path,
             w,
             h,
             buffer->media_status,
             video ? "Space/p toggles playback. q quits window." : "q quits window.");
    buffer_append(buffer, info);
    buffer->modified = 0;
    buffer->read_only = 1;
    return ECEX_OK;
}

int ecex_media_open(ecex_t *ed, const char *path) {
    if (!ed || !path || !ecex_path_is_media(path)) return ECEX_ERR;
    int video = ecex_path_is_video(path);
    buffer_t *buffer = media_buffer_for_path(ed, path, video);
    if (!buffer) return ECEX_ERR;
    ecex_media_load_into_buffer(ed, path, buffer);
    return ecex_switch_buffer(ed, buffer->name);
}

int ecex_media_toggle_playback(ecex_t *ed) {
    buffer_t *buffer = ecex_current_buffer(ed);
    if (!buffer || buffer->media_kind != ECEX_MEDIA_VIDEO) return ECEX_ERR;
    buffer->media_playing = !buffer->media_playing;
    snprintf(buffer->media_status,
             sizeof(buffer->media_status),
             "%s",
             buffer->media_playing ? "Playing" : "Paused");
    return ECEX_OK;
}

int ecex_media_tick(ecex_t *ed, double now_seconds) {
    if (!ed) return 0;
    int dirty = 0;
    for (size_t i = 0; i < ed->buffer_count; i++) {
        buffer_t *buffer = ed->buffers[i];
        if (!buffer || buffer->media_kind != ECEX_MEDIA_VIDEO || !buffer->media_pipe || !buffer->media_playing) continue;
        if (buffer->media_last_frame_time > 0.0 && now_seconds - buffer->media_last_frame_time < (1.0 / 60.0)) continue;

        int w = 0, h = 0;
        unsigned char *rgba = NULL;
        if (read_ppm_frame((FILE *)buffer->media_pipe, &w, &h, &rgba) == ECEX_OK) {
            set_buffer_pixels(buffer, w, h, rgba);
            buffer->media_last_frame_time = now_seconds;
            dirty = 1;
        } else {
            pclose((FILE *)buffer->media_pipe);
            buffer->media_pipe = NULL;
            buffer->media_playing = 0;
            snprintf(buffer->media_status, sizeof(buffer->media_status), "Playback finished");
            dirty = 1;
        }
    }
    return dirty;
}