path: root/src/FileAnalyzer.cpp

#include "../include/FileAnalyzer.hpp"
#include "../include/AsyncImageLoader.hpp"
#include "../include/Program.hpp"
#include "../include/StringUtils.hpp"
#include <sys/stat.h>
#include <stdio.h>
#include <array>
#include <json/reader.h> // TODO: Remove this dependency

static const int MAGIC_NUMBER_BUFFER_SIZE = 36;

namespace QuickMedia {
    struct MagicNumber {
        std::array<int, MAGIC_NUMBER_BUFFER_SIZE> data;
        size_t size;
        ContentType content_type;
    };

    // Sources:
    // https://en.wikipedia.org/wiki/List_of_file_signatures
    // https://mimesniff.spec.whatwg.org/

    // TODO: Test all of these
    static const std::array<MagicNumber, 33> magic_numbers = {
        MagicNumber{ {'R', 'I', 'F', 'F', -1, -1, -1, -1, 'A', 'V', 'I', ' '}, 12, ContentType::VIDEO_AVI },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', 'p', 'i', 's', 'o', 'm'}, 12, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', 'p', 'i', 's', 'o', '5'}, 12, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', 'p', 'm', 'p', '4', '2'}, 12, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', 'p', 'M', '4', 'V'}, 11, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', 'p', '3', 'g', 'p', '4'}, 12, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', 'p', '3', 'g', 'p', '5'}, 12, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', 'm', 'p', '4', '2'}, 11, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', '3', 'g', 'p', '5'}, 11, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x00, -1, 'f', 't', 'y', 'p', 'q', 't'}, 10, ContentType::VIDEO_MP4 },
        MagicNumber{ {0x00, 0x00, 0x01, 0xBA}, 4, ContentType::VIDEO_MPEG },
        MagicNumber{ {0x00, 0x00, 0x01, 0xB3}, 4, ContentType::VIDEO_MPEG },
        MagicNumber{ {0x1A, 0x45, 0xDF, 0xA3}, 4, ContentType::VIDEO_WEBM },
        MagicNumber{ {'F', 'L', 'V', 0x01}, 4, ContentType::VIDEO_FLV },
        MagicNumber{ {0x30, 0x26, 0xB2, 0x75, 0x8E, 0x66, 0xCF}, 7, ContentType::VIDEO_WMV },
        MagicNumber{ {'.', 's', 'n', 'd'}, 4, ContentType::AUDIO_BASIC },
        MagicNumber{ {'F', 'O', 'R', 'M', -1, -1, -1, -1, 'A', 'I', 'F', 'F'}, 12, ContentType::AUDIO_AIFF },
        MagicNumber{ { 'I', 'D', '3' }, 3, ContentType::AUDIO_MPEG },
        MagicNumber{ { 0xFF, 0xFB }, 2, ContentType::AUDIO_MPEG },
        MagicNumber{ { 0xFF, 0xF3 }, 2, ContentType::AUDIO_MPEG },
        MagicNumber{ { 0xFF, 0xF2 }, 2, ContentType::AUDIO_MPEG },
        //MagicNumber{ {'O', 'g', 'g', 'S', 0x00}, 5 },
        MagicNumber{ {'M', 'T', 'h', 'd', -1, -1, -1, -1}, 8, ContentType::AUDIO_MIDI },
        MagicNumber{ {'R', 'I', 'F', 'F', -1, -1, -1, -1, 'W', 'A', 'V', 'E'}, 12, ContentType::AUDIO_WAVE },
        MagicNumber{ {'f', 'L', 'a', 'C'}, 4, ContentType::AUDIO_FLAC },
        MagicNumber{ {'O', 'g', 'g', 'S', 0x00, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 ,-1, -1, -1, -1, -1, -1, -1, -1, 'v', 'o', 'r', 'b', 'i', 's'}, 35, ContentType::AUDIO_VORBIS },
        MagicNumber{ {'O', 'g', 'g', 'S', 0x00, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 ,-1, -1, -1, -1, -1, -1, -1, 'O', 'p', 'u', 's', 'H', 'e', 'a', 'd'}, 36, ContentType::AUDIO_OPUS },
        MagicNumber{ {0xFF, 0xD8, 0xFF}, 3, ContentType::IMAGE_JPEG },
        MagicNumber{ {0x89, 'P', 'N', 'G', 0x0D, 0x0A, 0x1A, 0x0A}, 8, ContentType::IMAGE_PNG },
        MagicNumber{ {'G', 'I', 'F', '8', '7', 'a'}, 6, ContentType::IMAGE_GIF },
        MagicNumber{ {'G', 'I', 'F', '8', '9', 'a'}, 6, ContentType::IMAGE_GIF },
        MagicNumber{ {'B', 'M'}, 2, ContentType::IMAGE_BMP },
        MagicNumber{ {'R', 'I', 'F', 'F', -1, -1, -1, -1, 'W', 'E', 'B', 'P'}, 12, ContentType::IMAGE_WEBP },
        MagicNumber{ {'R', 'I', 'F', 'F', -1, -1, -1, -1, 'W', 'E', 'B', 'V', 'P'}, 13, ContentType::IMAGE_WEBP }
    };

    bool is_content_type_video(ContentType content_type) {
        return content_type >= ContentType::VIDEO_AVI && content_type <= ContentType::VIDEO_WMV;
    }

    bool is_content_type_audio(ContentType content_type) {
        return content_type >= ContentType::AUDIO_BASIC && content_type <= ContentType::AUDIO_OPUS;
    }

    bool is_content_type_image(ContentType content_type) {
        return content_type >= ContentType::IMAGE_JPEG && content_type <= ContentType::IMAGE_WEBP;
    }

    const char* content_type_to_string(ContentType content_type) {
        switch(content_type) {
            case ContentType::UNKNOWN:      return "application/octet-stream";
            case ContentType::VIDEO_AVI:    return "video/avi";
            case ContentType::VIDEO_MP4:    return "video/mp4";
            case ContentType::VIDEO_MPEG:   return "video/mpeg";
            case ContentType::VIDEO_WEBM:   return "video/webm";
            case ContentType::VIDEO_FLV:    return "video/x-flv";
            case ContentType::VIDEO_WMV:    return "video/x-ms-asf";
            case ContentType::AUDIO_BASIC:  return "audio/basic";
            case ContentType::AUDIO_AIFF:   return "audio/aiff";
            case ContentType::AUDIO_MPEG:   return "audio/mpeg";
            case ContentType::AUDIO_MIDI:   return "audio/midi";
            case ContentType::AUDIO_WAVE:   return "audio/wave";
            case ContentType::AUDIO_FLAC:   return "audio/flac";
            case ContentType::AUDIO_VORBIS: return "audio/ogg";
            case ContentType::AUDIO_OPUS:   return "audio/opus";
            case ContentType::IMAGE_JPEG:   return "image/jpeg";
            case ContentType::IMAGE_PNG:    return "image/png";
            case ContentType::IMAGE_GIF:    return "image/gif";
            case ContentType::IMAGE_BMP:    return "image/bmp";
            case ContentType::IMAGE_WEBP:   return "image/webp";
        }
        return "application/octet-stream";
    }

    bool is_image_ext(const char *ext) {
        return strcase_equals(ext, ".jpg")
            || strcase_equals(ext, ".jpeg")
            || strcase_equals(ext, ".png")
            || strcase_equals(ext, ".gif")
            || strcase_equals(ext, ".webp");
    }

    bool is_video_ext(const char *ext) {
        return strcase_equals(ext, ".webm")
            || strcase_equals(ext, ".mkv")
            || strcase_equals(ext, ".flv")
            || strcase_equals(ext, ".vob")
            || strcase_equals(ext, ".ogv")
            //|| strcase_equals(ext, ".ogg")
            || strcase_equals(ext, ".avi")
            //|| strcase_equals(ext, ".ts")
            || strcase_equals(ext, ".mov")
            || strcase_equals(ext, ".qt")
            || strcase_equals(ext, ".wmv")
            || strcase_equals(ext, ".mp4")
            || strcase_equals(ext, ".m4v")
            || strcase_equals(ext, ".mpg")
            || strcase_equals(ext, ".mpeg")
            || strcase_equals(ext, ".3gp");
    }

    bool is_music_ext(const char *ext) {
        return strcase_equals(ext, ".aac")
            || strcase_equals(ext, ".alac")
            || strcase_equals(ext, ".flac")
            || strcase_equals(ext, ".m4a")
            || strcase_equals(ext, ".m4p")
            || strcase_equals(ext, ".mp3")
            || strcase_equals(ext, ".ogg")
            || strcase_equals(ext, ".oga")
            || strcase_equals(ext, ".mogg")
            || strcase_equals(ext, ".opus")
            || strcase_equals(ext, ".vox")
            || strcase_equals(ext, ".wav")
            || strcase_equals(ext, ".wma")
            || strcase_equals(ext, ".mid");
    }

    bool video_get_frame(const FileAnalyzer &file, const char *destination_path, int width, int height, int seconds) {
        Path destination_path_tmp = destination_path;
        destination_path_tmp.append(".tmp.jpg"); // TODO: .png, but the below code also needs to be changed for that

        char seconds_str[32];
        snprintf(seconds_str, sizeof(seconds_str), "%d", seconds);

        int allowed_exit_status[] = { 0, 69 };

        if(width > 0 && height > 0) {
            char size_arg_str[512];
            snprintf(size_arg_str, sizeof(size_arg_str), "scale=%d:%d:force_original_aspect_ratio=decrease", width, height);

            const char *program_args[] = { "ffmpeg", "-y", "-v", "quiet", "-ss", seconds_str, "-i", file.get_filepath().c_str(), "-frames:v", "1", "-vf", size_arg_str, "--", destination_path_tmp.data.c_str(), nullptr };
            if(exec_program(program_args, nullptr, nullptr, allowed_exit_status, 2) != 0) {
                fprintf(stderr, "Failed to execute ffmpeg, maybe its not installed?\n");
                return false;
            }
        } else {
            const char *program_args[] = { "ffmpeg", "-y", "-v", "quiet", "-ss", seconds_str, "-i", file.get_filepath().c_str(), "-frames:v", "1", "--", destination_path_tmp.data.c_str(), nullptr };
            if(exec_program(program_args, nullptr, nullptr, allowed_exit_status, 2) != 0) {
                fprintf(stderr, "Failed to execute ffmpeg, maybe its not installed?\n");
                return false;
            }
        }

        return rename_atomic(destination_path_tmp.data.c_str(), destination_path) == 0;
    }

    bool video_get_start_frame(const FileAnalyzer &file, const char *destination_path, int width, int height) {
        const int start_seconds = std::max(0.0, std::min(3.0, file.get_duration_seconds().value_or(0.0) - 1.0));
        return video_get_frame(file, destination_path, width, height, start_seconds);
    }

    bool video_get_middle_frame(const FileAnalyzer &file, const char *destination_path, int width, int height) {
        const int middle_seconds = file.get_duration_seconds().value_or(0.0) / 2.0;
        return video_get_frame(file, destination_path, width, height, middle_seconds);
    }

    // TODO: Remove dependency on ffprobe
    static bool ffprobe_extract_metadata(const char *filepath, std::optional<Dimensions> &dimensions, std::optional<double> &duration_seconds) {
        const char *program_args[] = { "ffprobe", "-v", "quiet", "-print_format", "json", "-show_streams", "-show_format", "--", filepath, nullptr };
        std::string ffprobe_result;
        if(exec_program(program_args, accumulate_string, &ffprobe_result) != 0) {
            fprintf(stderr, "Failed to execute ffprobe, maybe its not installed?\n");
            return false;
        }

        Json::Value json_root;
        Json::CharReaderBuilder json_builder;
        std::unique_ptr<Json::CharReader> json_reader(json_builder.newCharReader());
        std::string json_errors;
        if(!json_reader->parse(&ffprobe_result[0], &ffprobe_result[ffprobe_result.size()], &json_root, &json_errors)) {
            fprintf(stderr, "ffprobe response parsing failed: %s\n", json_errors.c_str());
            return false;
        }

        if(!json_root.isObject())
            return false;

        const Json::Value &streams_json = json_root["streams"];
        if(!streams_json.isArray())
            return false;

        for(const Json::Value &stream_json : streams_json) {
            if(!stream_json.isObject())
                continue;

            const Json::Value &codec_type = stream_json["codec_type"];
            if(!codec_type.isString())
                continue;

            if(strcmp(codec_type.asCString(), "video") == 0) {
                const Json::Value &width_json = stream_json["width"];
                const Json::Value &height_json = stream_json["height"];
                if(width_json.isNumeric() && height_json.isNumeric())
                    dimensions = { width_json.asInt(), height_json.asInt() };
            }
        }

        const Json::Value &format_json = json_root["format"];
        if(!format_json.isObject())
            return true;

        const Json::Value &duration_json = format_json["duration"];
        if(duration_json.isString())
            duration_seconds = atof(duration_json.asCString());

        return true;
    }

    FileAnalyzer::FileAnalyzer() : content_type(ContentType::UNKNOWN), file_size(0), loaded(false), metadata_loaded(false) {

    }

    bool FileAnalyzer::load_file(const char *filepath, bool load_file_metadata) {
        if(loaded) {
            fprintf(stderr, "File already loaded\n");
            return false;
        }

        FILE *file = fopen(filepath, "rb");
        if(!file) {
            perror(filepath);
            return false;
        }

        content_type = ContentType::UNKNOWN;
        file_size = 0;
        dimensions = std::nullopt;
        duration_seconds = std::nullopt;

        struct stat64 stat;
        memset(&stat, 0, sizeof(stat));
        if(fstat64(fileno(file), &stat) == -1) {
            perror(filepath);
            fclose(file);
            return false;
        }

        file_size = stat.st_size;

        unsigned char magic_number_buffer[MAGIC_NUMBER_BUFFER_SIZE];
        size_t num_bytes_read = fread(magic_number_buffer, 1, sizeof(magic_number_buffer), file);
        if(feof(file) || num_bytes_read != sizeof(magic_number_buffer)) {
            perror(filepath);
            fclose(file);
            return false;
        }
        fclose(file);
        
        for(const MagicNumber &magic_number : magic_numbers) {
            if(num_bytes_read >= magic_number.size) {
                bool matching_magic_numbers = true;
                for(size_t i = 0; i < magic_number.size; ++i) {
                    if(magic_number.data[i] != (int)magic_number_buffer[i] && (int)magic_number.data[i] != -1) {
                        matching_magic_numbers = false;
                        break;
                    }
                }
                if(matching_magic_numbers) {
                    content_type = magic_number.content_type;
                    break;
                }
            }
        }

        this->filepath = filepath;
        loaded = true;

        if(load_file_metadata && content_type != ContentType::UNKNOWN)
            load_metadata();

        return true;
    }

    bool FileAnalyzer::load_metadata() {
        if(!loaded) {
            fprintf(stderr, "File not loaded\n");
            return false;
        }

        if(metadata_loaded)
            return true;

        metadata_loaded = true;

        if(!ffprobe_extract_metadata(filepath.c_str(), dimensions, duration_seconds)) {
            // This is not an error, matrix allows files to be uploaded without metadata
            fprintf(stderr, "Failed to extract metadata from file: %s, is ffprobe not installed?\n", filepath.c_str());
            return false;
        }

        if(is_content_type_image(content_type))
            duration_seconds = std::nullopt;

        return true;
    }

    const std::string& FileAnalyzer::get_filepath() const {
        return filepath;
    }

    ContentType FileAnalyzer::get_content_type() const {
        return content_type;
    }

    int64_t FileAnalyzer::get_file_size() const {
        return file_size;
    }

    std::optional<Dimensions> FileAnalyzer::get_dimensions() const {
        return dimensions;
    }

    std::optional<double> FileAnalyzer::get_duration_seconds() const {
        return duration_seconds;
    }
}