use super::{Descriptor, MediaType};
use crate::{
    error::{OciSpecError, Result},
    from_file, from_reader, to_file, to_string, to_writer,
};
use derive_builder::Builder;
use getset::{CopyGetters, Getters, Setters};
use serde::{Deserialize, Serialize};
use std::{
    collections::HashMap,
    fmt::Display,
    io::{Read, Write},
    path::Path,
};

/// The expected schema version; equals 2 for compatibility with older versions of Docker.
pub const SCHEMA_VERSION: u32 = 2;

#[derive(
    Builder, Clone, CopyGetters, Debug, Deserialize, Eq, Getters, Setters, PartialEq, Serialize,
)]
#[serde(rename_all = "camelCase")]
#[builder(
    pattern = "owned",
    setter(into, strip_option),
    build_fn(error = "OciSpecError")
)]
/// The image index is a higher-level manifest which points to specific
/// image manifests, ideal for one or more platforms. While the use of
/// an image index is OPTIONAL for image providers, image consumers
/// SHOULD be prepared to process them.
pub struct ImageIndex {
    /// This REQUIRED property specifies the image manifest schema version.
    /// For this version of the specification, this MUST be 2 to ensure
    /// backward compatibility with older versions of Docker. The
    /// value of this field will not change. This field MAY be
    /// removed in a future version of the specification.
    #[getset(get_copy = "pub", set = "pub")]
    schema_version: u32,
    /// This property is reserved for use, to maintain compatibility. When
    /// used, this field contains the media type of this document,
    /// which differs from the descriptor use of mediaType.
    #[serde(skip_serializing_if = "Option::is_none")]
    #[getset(get = "pub", set = "pub")]
    #[builder(default)]
    media_type: Option<MediaType>,
    /// This OPTIONAL property contains the type of an artifact when the manifest is used for an
    /// artifact. If defined, the value MUST comply with RFC 6838, including the naming
    /// requirements in its section 4.2, and MAY be registered with IANA.
    #[serde(skip_serializing_if = "Option::is_none")]
    #[getset(get = "pub", set = "pub")]
    #[builder(default)]
    artifact_type: Option<MediaType>,
    /// This REQUIRED property contains a list of manifests for specific
    /// platforms. While this property MUST be present, the size of
    /// the array MAY be zero.
    #[getset(get = "pub", set = "pub")]
    manifests: Vec<Descriptor>,
    /// This OPTIONAL property specifies a descriptor of another manifest. This value, used by the
    /// referrers API, indicates a relationship to the specified manifest.
    #[serde(skip_serializing_if = "Option::is_none")]
    #[getset(get = "pub", set = "pub")]
    #[builder(default)]
    subject: Option<Descriptor>,
    /// This OPTIONAL property contains arbitrary metadata for the image
    /// index. This OPTIONAL property MUST use the annotation rules.
    #[serde(skip_serializing_if = "Option::is_none")]
    #[getset(get = "pub", set = "pub")]
    #[builder(default)]
    annotations: Option<HashMap<String, String>>,
}

impl ImageIndex {
    /// Attempts to load an image index from a file.
    /// # Errors
    /// This function will return an [OciSpecError::Io](crate::OciSpecError::Io)
    /// if the file does not exist or an
    /// [OciSpecError::SerDe](crate::OciSpecError::SerDe) if the image index
    /// cannot be deserialized.
    /// # Example
    /// ``` no_run
    /// use oci_spec::image::ImageIndex;
    ///
    /// let image_index = ImageIndex::from_file("index.json").unwrap();
    /// ```
    pub fn from_file<P: AsRef<Path>>(path: P) -> Result<ImageIndex> {
        from_file(path)
    }

    /// Attempts to load an image index from a stream.
    /// # Errors
    /// This function will return an [OciSpecError::SerDe](crate::OciSpecError::SerDe)
    /// if the index cannot be deserialized.
    /// # Example
    /// ``` no_run
    /// use oci_spec::image::ImageIndex;
    /// use std::fs::File;
    ///
    /// let reader = File::open("index.json").unwrap();
    /// let image_index = ImageIndex::from_reader(reader).unwrap();
    /// ```
    pub fn from_reader<R: Read>(reader: R) -> Result<ImageIndex> {
        from_reader(reader)
    }

    /// Attempts to write an image index to a file as JSON. If the file already exists, it
    /// will be overwritten.
    /// # Errors
    /// This function will return an [OciSpecError::SerDe](crate::OciSpecError::SerDe) if
    /// the image index cannot be serialized.
    /// # Example
    /// ``` no_run
    /// use oci_spec::image::ImageIndex;
    ///
    /// let image_index = ImageIndex::from_file("index.json").unwrap();
    /// image_index.to_file("my-index.json").unwrap();
    /// ```
    pub fn to_file<P: AsRef<Path>>(&self, path: P) -> Result<()> {
        to_file(&self, path, false)
    }

    /// Attempts to write an image index to a file as pretty printed JSON. If the file
    /// already exists, it will be overwritten.
    /// # Errors
    /// This function will return an [OciSpecError::SerDe](crate::OciSpecError::SerDe) if
    /// the image index cannot be serialized.
    /// # Example
    /// ``` no_run
    /// use oci_spec::image::ImageIndex;
    ///
    /// let image_index = ImageIndex::from_file("index.json").unwrap();
    /// image_index.to_file_pretty("my-index.json").unwrap();
    /// ```
    pub fn to_file_pretty<P: AsRef<Path>>(&self, path: P) -> Result<()> {
        to_file(&self, path, true)
    }

    /// Attempts to write an image index to a stream as JSON.
    /// # Errors
    /// This function will return an [OciSpecError::SerDe](crate::OciSpecError::SerDe) if
    /// the image index cannot be serialized.
    /// # Example
    /// ``` no_run
    /// use oci_spec::image::ImageIndex;
    ///
    /// let image_index = ImageIndex::from_file("index.json").unwrap();
    /// let mut writer = Vec::new();
    /// image_index.to_writer(&mut writer);
    /// ```
    pub fn to_writer<W: Write>(&self, writer: &mut W) -> Result<()> {
        to_writer(&self, writer, false)
    }

    /// Attempts to write an image index to a stream as pretty printed JSON.
    /// # Errors
    /// This function will return an [OciSpecError::SerDe](crate::OciSpecError::SerDe) if
    /// the image index cannot be serialized.
    /// # Example
    /// ``` no_run
    /// use oci_spec::image::ImageIndex;
    ///
    /// let image_index = ImageIndex::from_file("index.json").unwrap();
    /// let mut writer = Vec::new();
    /// image_index.to_writer_pretty(&mut writer);
    /// ```
    pub fn to_writer_pretty<W: Write>(&self, writer: &mut W) -> Result<()> {
        to_writer(&self, writer, true)
    }

    /// Attempts to write an image index to a string as JSON.
    /// # Errors
    /// This function will return an [OciSpecError::SerDe](crate::OciSpecError::SerDe) if
    /// the image configuration cannot be serialized.
    /// # Example
    /// ``` no_run
    /// use oci_spec::image::ImageIndex;
    ///
    /// let image_index = ImageIndex::from_file("index.json").unwrap();
    /// let json_str = image_index.to_string().unwrap();
    /// ```
    pub fn to_string(&self) -> Result<String> {
        to_string(&self, false)
    }

    /// Attempts to write an image index to a string as pretty printed JSON.
    /// # Errors
    /// This function will return an [OciSpecError::SerDe](crate::OciSpecError::SerDe) if
    /// the image configuration cannot be serialized.
    /// # Example
    /// ``` no_run
    /// use oci_spec::image::ImageIndex;
    ///
    /// let image_index = ImageIndex::from_file("index.json").unwrap();
    /// let json_str = image_index.to_string_pretty().unwrap();
    /// ```
    pub fn to_string_pretty(&self) -> Result<String> {
        to_string(&self, true)
    }
}

impl Default for ImageIndex {
    fn default() -> Self {
        Self {
            schema_version: SCHEMA_VERSION,
            media_type: Default::default(),
            manifests: Default::default(),
            annotations: Default::default(),
            artifact_type: Default::default(),
            subject: Default::default(),
        }
    }
}

/// This ToString trait is automatically implemented for any type which implements the Display trait.
/// As such, ToString shouldn’t be implemented directly: Display should be implemented instead,
/// and you get the ToString implementation for free.
impl Display for ImageIndex {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        // Serde seralization never fails since this is
        // a combination of String and enums.
        write!(
            f,
            "{}",
            self.to_string_pretty()
                .expect("ImageIndex to JSON convertion failed")
        )
    }
}

#[cfg(test)]
mod tests {
    use std::{fs, path::PathBuf};

    use super::*;
    use crate::image::{Arch, Os};
    use crate::image::{DescriptorBuilder, PlatformBuilder};

    fn create_index() -> ImageIndex {
        let ppc_manifest = DescriptorBuilder::default()
            .media_type(MediaType::ImageManifest)
            .digest("sha256:e692418e4cbaf90ca69d05a66403747baa33ee08806650b51fab815ad7fc331f")
            .size(7143)
            .platform(
                PlatformBuilder::default()
                    .architecture(Arch::PowerPC64le)
                    .os(Os::Linux)
                    .build()
                    .expect("build ppc64le platform"),
            )
            .build()
            .expect("build ppc manifest descriptor");

        let amd64_manifest = DescriptorBuilder::default()
            .media_type(MediaType::ImageManifest)
            .digest("sha256:5b0bcabd1ed22e9fb1310cf6c2dec7cdef19f0ad69efa1f392e94a4333501270")
            .size(7682)
            .platform(
                PlatformBuilder::default()
                    .architecture(Arch::Amd64)
                    .os(Os::Linux)
                    .build()
                    .expect("build amd64 platform"),
            )
            .build()
            .expect("build amd64 manifest descriptor");

        ImageIndexBuilder::default()
            .schema_version(SCHEMA_VERSION)
            .manifests(vec![ppc_manifest, amd64_manifest])
            .build()
            .expect("build image index")
    }

    fn get_index_path() -> PathBuf {
        PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("test/data/index.json")
    }

    #[test]
    fn load_index_from_file() {
        // arrange
        let index_path = get_index_path();

        // act
        let actual = ImageIndex::from_file(index_path).expect("from file");

        // assert
        let expected = create_index();
        assert_eq!(actual, expected);
    }

    #[test]
    fn load_index_from_reader() {
        // arrange
        let reader = fs::read(get_index_path()).expect("read index");

        // act
        let actual = ImageIndex::from_reader(&*reader).expect("from reader");

        // assert
        let expected = create_index();
        assert_eq!(actual, expected);
    }

    #[test]
    fn save_index_to_file() {
        // arrange
        let tmp = std::env::temp_dir().join("save_index_to_file");
        fs::create_dir_all(&tmp).expect("create test directory");
        let index = create_index();
        let index_path = tmp.join("index.json");

        // act
        index
            .to_file_pretty(&index_path)
            .expect("write index to file");

        // assert
        let actual = fs::read_to_string(index_path).expect("read actual");
        let expected = fs::read_to_string(get_index_path()).expect("read expected");
        assert_eq!(actual, expected);
    }

    #[test]
    fn save_index_to_writer() {
        // arrange
        let mut actual = Vec::new();
        let index = create_index();

        // act
        index.to_writer_pretty(&mut actual).expect("to writer");

        // assert
        let expected = fs::read(get_index_path()).expect("read expected");
        assert_eq!(actual, expected);
    }

    #[test]
    fn save_index_to_string() {
        // arrange
        let index = create_index();

        // act
        let actual = index.to_string_pretty().expect("to string");

        // assert
        let expected = fs::read_to_string(get_index_path()).expect("read expected");
        assert_eq!(actual, expected);
    }
}