use std::fs::File;
use std::io::{BufReader, Read};

use flate2::bufread::GzDecoder;
use serde::Deserialize;
use tempfile::TempDir;

use self::compat::v4_to_v5::CompatV4ToV5;
use self::compat::v5_to_v6::{CompatIndexV5ToV6, CompatV5ToV6};
use self::v5::V5Reader;
use self::v6::{V6IndexReader, V6Reader};
use crate::{Error, Result, Version};

mod compat;

// pub(self) mod v1;
pub(self) mod v2;
pub(self) mod v3;
pub(self) mod v4;
pub(self) mod v5;
pub(self) mod v6;

pub type Document = serde_json::Map<String, serde_json::Value>;
pub type UpdateFile = dyn Iterator<Item = Result<Document>>;

pub enum DumpReader {
    Current(V6Reader),
    Compat(CompatV5ToV6),
}

impl DumpReader {
    pub fn open(dump: impl Read) -> Result<DumpReader> {
        let path = TempDir::new()?;
        let mut dump = BufReader::new(dump);
        let gz = GzDecoder::new(&mut dump);
        let mut archive = tar::Archive::new(gz);
        archive.unpack(path.path())?;

        #[derive(Deserialize)]
        #[serde(rename_all = "camelCase")]
        struct MetadataVersion {
            pub dump_version: Version,
        }
        let mut meta_file = File::open(path.path().join("metadata.json"))?;
        let MetadataVersion { dump_version } = serde_json::from_reader(&mut meta_file)?;

        match dump_version {
            // Version::V1 => Ok(Box::new(v1::Reader::open(path)?)),
            Version::V1 => Err(Error::DumpV1Unsupported),
            Version::V2 => Ok(v2::V2Reader::open(path)?.to_v3().to_v4().to_v5().to_v6().into()),
            Version::V3 => Ok(v3::V3Reader::open(path)?.to_v4().to_v5().to_v6().into()),
            Version::V4 => Ok(v4::V4Reader::open(path)?.to_v5().to_v6().into()),
            Version::V5 => Ok(v5::V5Reader::open(path)?.to_v6().into()),
            Version::V6 => Ok(v6::V6Reader::open(path)?.into()),
        }
    }

    pub fn version(&self) -> crate::Version {
        match self {
            DumpReader::Current(current) => current.version(),
            DumpReader::Compat(compat) => compat.version(),
        }
    }

    pub fn date(&self) -> Option<time::OffsetDateTime> {
        match self {
            DumpReader::Current(current) => current.date(),
            DumpReader::Compat(compat) => compat.date(),
        }
    }

    pub fn instance_uid(&self) -> Result<Option<uuid::Uuid>> {
        match self {
            DumpReader::Current(current) => current.instance_uid(),
            DumpReader::Compat(compat) => compat.instance_uid(),
        }
    }

    pub fn indexes(&self) -> Result<Box<dyn Iterator<Item = Result<DumpIndexReader>> + '_>> {
        match self {
            DumpReader::Current(current) => {
                let indexes = Box::new(current.indexes()?.map(|res| res.map(DumpIndexReader::from)))
                    as Box<dyn Iterator<Item = Result<DumpIndexReader>> + '_>;
                Ok(indexes)
            }
            DumpReader::Compat(compat) => {
                let indexes = Box::new(compat.indexes()?.map(|res| res.map(DumpIndexReader::from)))
                    as Box<dyn Iterator<Item = Result<DumpIndexReader>> + '_>;
                Ok(indexes)
            }
        }
    }

    pub fn tasks(
        &mut self,
    ) -> Result<Box<dyn Iterator<Item = Result<(v6::Task, Option<Box<UpdateFile>>)>> + '_>> {
        match self {
            DumpReader::Current(current) => Ok(current.tasks()),
            DumpReader::Compat(compat) => compat.tasks(),
        }
    }

    pub fn keys(&mut self) -> Result<Box<dyn Iterator<Item = Result<v6::Key>> + '_>> {
        match self {
            DumpReader::Current(current) => Ok(current.keys()),
            DumpReader::Compat(compat) => compat.keys(),
        }
    }
}

impl From<V6Reader> for DumpReader {
    fn from(value: V6Reader) -> Self {
        DumpReader::Current(value)
    }
}

impl From<CompatV5ToV6> for DumpReader {
    fn from(value: CompatV5ToV6) -> Self {
        DumpReader::Compat(value)
    }
}

impl From<V5Reader> for DumpReader {
    fn from(value: V5Reader) -> Self {
        DumpReader::Compat(value.to_v6())
    }
}

impl From<CompatV4ToV5> for DumpReader {
    fn from(value: CompatV4ToV5) -> Self {
        DumpReader::Compat(value.to_v6())
    }
}

pub enum DumpIndexReader {
    Current(v6::V6IndexReader),
    Compat(CompatIndexV5ToV6),
}

impl DumpIndexReader {
    pub fn new_v6(v6: v6::V6IndexReader) -> DumpIndexReader {
        DumpIndexReader::Current(v6)
    }

    pub fn metadata(&self) -> &crate::IndexMetadata {
        match self {
            DumpIndexReader::Current(v6) => v6.metadata(),
            DumpIndexReader::Compat(compat) => compat.metadata(),
        }
    }

    pub fn documents(&mut self) -> Result<Box<dyn Iterator<Item = Result<Document>> + '_>> {
        match self {
            DumpIndexReader::Current(v6) => v6
                .documents()
                .map(|iter| Box::new(iter) as Box<dyn Iterator<Item = Result<Document>> + '_>),
            DumpIndexReader::Compat(compat) => compat
                .documents()
                .map(|iter| Box::new(iter) as Box<dyn Iterator<Item = Result<Document>> + '_>),
        }
    }

    pub fn settings(&mut self) -> Result<v6::Settings<v6::Checked>> {
        match self {
            DumpIndexReader::Current(v6) => v6.settings(),
            DumpIndexReader::Compat(compat) => compat.settings(),
        }
    }
}

impl From<V6IndexReader> for DumpIndexReader {
    fn from(value: V6IndexReader) -> Self {
        DumpIndexReader::Current(value)
    }
}

impl From<CompatIndexV5ToV6> for DumpIndexReader {
    fn from(value: CompatIndexV5ToV6) -> Self {
        DumpIndexReader::Compat(value)
    }
}

#[cfg(test)]
pub(crate) mod test {
    use std::fs::File;

    use super::*;

    #[test]
    fn import_dump_v5() {
        let dump = File::open("tests/assets/v5.dump").unwrap();
        let mut dump = DumpReader::open(dump).unwrap();

        // top level infos
        insta::assert_display_snapshot!(dump.date().unwrap(), @"2022-10-04 15:55:10.344982459 +00:00:00");
        insta::assert_display_snapshot!(dump.instance_uid().unwrap().unwrap(), @"9e15e977-f2ae-4761-943f-1eaf75fd736d");

        // tasks
        let tasks = dump.tasks().unwrap().collect::<Result<Vec<_>>>().unwrap();
        let (tasks, update_files): (Vec<_>, Vec<_>) = tasks.into_iter().unzip();
        meili_snap::snapshot_hash!(meili_snap::json_string!(tasks), @"b37c01556be2e5ded407a9319915b406");
        assert_eq!(update_files.len(), 22);
        assert!(update_files[0].is_none()); // the dump creation
        assert!(update_files[1].is_some()); // the enqueued document addition
        assert!(update_files[2..].iter().all(|u| u.is_none())); // everything already processed

        // keys
        let keys = dump.keys().unwrap().collect::<Result<Vec<_>>>().unwrap();
        meili_snap::snapshot_hash!(meili_snap::json_string!(keys), @"c9d2b467fe2fca0b35580d8a999808fb");

        // indexes
        let mut indexes = dump.indexes().unwrap().collect::<Result<Vec<_>>>().unwrap();
        // the index are not ordered in any way by default
        indexes.sort_by_key(|index| index.metadata().uid.to_string());

        let mut products = indexes.pop().unwrap();
        let mut movies = indexes.pop().unwrap();
        let mut spells = indexes.pop().unwrap();
        assert!(indexes.is_empty());

        // products
        insta::assert_json_snapshot!(products.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "products",
          "primaryKey": "sku",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", products.settings()), @"9896a66a399c24a0f4f6a3c8563cd14a");
        let documents = products.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 10);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"b01c8371aea4c7171af0d4d846a2bdca");

        // movies
        insta::assert_json_snapshot!(movies.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "movies",
          "primaryKey": "id",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", movies.settings()), @"d0dc7efd1360f95fce57d7931a70b7c9");
        let documents = movies.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 200);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"e962baafd2fbae4cdd14e876053b0c5a");

        // spells
        insta::assert_json_snapshot!(spells.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "dnd_spells",
          "primaryKey": "index",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", spells.settings()), @"59c8e30c2022897987ea7b4394167b06");
        let documents = spells.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 10);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"235016433dd04262c7f2da01d1e808ce");
    }

    #[test]
    fn import_dump_v4() {
        let dump = File::open("tests/assets/v4.dump").unwrap();
        let mut dump = DumpReader::open(dump).unwrap();

        // top level infos
        insta::assert_display_snapshot!(dump.date().unwrap(), @"2022-10-06 12:53:49.131989609 +00:00:00");
        insta::assert_display_snapshot!(dump.instance_uid().unwrap().unwrap(), @"9e15e977-f2ae-4761-943f-1eaf75fd736d");

        // tasks
        let tasks = dump.tasks().unwrap().collect::<Result<Vec<_>>>().unwrap();
        let (tasks, update_files): (Vec<_>, Vec<_>) = tasks.into_iter().unzip();
        meili_snap::snapshot_hash!(meili_snap::json_string!(tasks), @"acd74244b4e6578c353899e6db30b0b5");
        assert_eq!(update_files.len(), 10);
        assert!(update_files[0].is_some()); // the enqueued document addition
        assert!(update_files[1..].iter().all(|u| u.is_none())); // everything already processed

        // keys
        let keys = dump.keys().unwrap().collect::<Result<Vec<_>>>().unwrap();
        meili_snap::snapshot_hash!(meili_snap::json_string!(keys, { "[].uid" => "[uuid]" }), @"d751713988987e9331980363e24189ce");

        // indexes
        let mut indexes = dump.indexes().unwrap().collect::<Result<Vec<_>>>().unwrap();
        // the index are not ordered in any way by default
        indexes.sort_by_key(|index| index.metadata().uid.to_string());

        let mut products = indexes.pop().unwrap();
        let mut movies = indexes.pop().unwrap();
        let mut spells = indexes.pop().unwrap();
        assert!(indexes.is_empty());

        // products
        insta::assert_json_snapshot!(products.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "products",
          "primaryKey": "sku",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", products.settings()), @"ed1a6977a832b1ab49cd5068b77ce498");
        let documents = products.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 10);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"b01c8371aea4c7171af0d4d846a2bdca");

        // movies
        insta::assert_json_snapshot!(movies.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "movies",
          "primaryKey": "id",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", movies.settings()), @"70681af1d52411218036fbd5a9b94ab5");
        let documents = movies.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 110);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"786022a66ecb992c8a2a60fee070a5ab");

        // spells
        insta::assert_json_snapshot!(spells.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "dnd_spells",
          "primaryKey": "index",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", spells.settings()), @"7019bb8f146004dcdd91fc3c3254b742");
        let documents = spells.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 10);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"235016433dd04262c7f2da01d1e808ce");
    }

    #[test]
    fn import_dump_v3() {
        let dump = File::open("tests/assets/v3.dump").unwrap();
        let mut dump = DumpReader::open(dump).unwrap();

        // top level infos
        insta::assert_display_snapshot!(dump.date().unwrap(), @"2022-10-07 11:39:03.709153554 +00:00:00");
        assert_eq!(dump.instance_uid().unwrap(), None);

        // tasks
        let tasks = dump.tasks().unwrap().collect::<Result<Vec<_>>>().unwrap();
        let (tasks, update_files): (Vec<_>, Vec<_>) = tasks.into_iter().unzip();
        meili_snap::snapshot_hash!(meili_snap::json_string!(tasks), @"fa74f7c6ab3014e09bb813fdc551db8f");
        assert_eq!(update_files.len(), 10);
        assert!(update_files[0].is_some()); // the enqueued document addition
        assert!(update_files[1..].iter().all(|u| u.is_none())); // everything already processed

        // keys
        let keys = dump.keys().unwrap().collect::<Result<Vec<_>>>().unwrap();
        meili_snap::snapshot_hash!(meili_snap::json_string!(keys), @"d751713988987e9331980363e24189ce");

        // indexes
        let mut indexes = dump.indexes().unwrap().collect::<Result<Vec<_>>>().unwrap();
        // the index are not ordered in any way by default
        indexes.sort_by_key(|index| index.metadata().uid.to_string());

        let mut products = indexes.pop().unwrap();
        let mut movies2 = indexes.pop().unwrap();
        let mut movies = indexes.pop().unwrap();
        let mut spells = indexes.pop().unwrap();
        assert!(indexes.is_empty());

        // products
        insta::assert_json_snapshot!(products.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "products",
          "primaryKey": "sku",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", products.settings()), @"1a5ed16d00e6163662d9d7ffe400c5d0");
        let documents = products.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 10);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"548284a84de510f71e88e6cdea495cf5");

        // movies
        insta::assert_json_snapshot!(movies.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "movies",
          "primaryKey": "id",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", movies.settings()), @"9a6b511669b8f53d193d2f0bd1671baa");
        let documents = movies.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 110);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"d153b5a81d8b3cdcbe1dec270b574022");

        // movies2
        insta::assert_json_snapshot!(movies2.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "movies_2",
          "primaryKey": null,
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", movies2.settings()), @"4fdf905496d9a511800ff523728728ac");
        let documents = movies2.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 0);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"d751713988987e9331980363e24189ce");

        // spells
        insta::assert_json_snapshot!(spells.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "dnd_spells",
          "primaryKey": "index",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", spells.settings()), @"4fdf905496d9a511800ff523728728ac");
        let documents = spells.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 10);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"235016433dd04262c7f2da01d1e808ce");
    }

    #[test]
    fn import_dump_v2() {
        let dump = File::open("tests/assets/v2.dump").unwrap();
        let mut dump = DumpReader::open(dump).unwrap();

        // top level infos
        insta::assert_display_snapshot!(dump.date().unwrap(), @"2022-10-09 20:27:59.904096267 +00:00:00");
        assert_eq!(dump.instance_uid().unwrap(), None);

        // tasks
        let tasks = dump.tasks().unwrap().collect::<Result<Vec<_>>>().unwrap();
        let (tasks, update_files): (Vec<_>, Vec<_>) = tasks.into_iter().unzip();
        meili_snap::snapshot_hash!(meili_snap::json_string!(tasks), @"19882e94dc085f1d60eb7df5005a3224");
        assert_eq!(update_files.len(), 9);
        assert!(update_files[0].is_some()); // the enqueued document addition
        assert!(update_files[1..].iter().all(|u| u.is_none())); // everything already processed

        // keys
        let keys = dump.keys().unwrap().collect::<Result<Vec<_>>>().unwrap();
        meili_snap::snapshot_hash!(meili_snap::json_string!(keys), @"d751713988987e9331980363e24189ce");

        // indexes
        let mut indexes = dump.indexes().unwrap().collect::<Result<Vec<_>>>().unwrap();
        // the index are not ordered in any way by default
        indexes.sort_by_key(|index| index.metadata().uid.to_string());

        let mut products = indexes.pop().unwrap();
        let mut movies2 = indexes.pop().unwrap();
        let mut movies = indexes.pop().unwrap();
        let mut spells = indexes.pop().unwrap();
        assert!(indexes.is_empty());

        // products
        insta::assert_json_snapshot!(products.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "products",
          "primaryKey": "sku",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", products.settings()), @"a7d4fed93bfc91d0f1126d3371abf48e");
        let documents = products.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 10);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"548284a84de510f71e88e6cdea495cf5");

        // movies
        insta::assert_json_snapshot!(movies.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "movies",
          "primaryKey": "id",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", movies.settings()), @"e79c3cc4eef44bd22acfb60957b459d9");
        let documents = movies.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 110);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"d153b5a81d8b3cdcbe1dec270b574022");

        // movies2
        insta::assert_json_snapshot!(movies2.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "movies_2",
          "primaryKey": null,
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", movies2.settings()), @"7917f954b6f345336073bb155540ad6d");
        let documents = movies2.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 0);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"d751713988987e9331980363e24189ce");

        // spells
        insta::assert_json_snapshot!(spells.metadata(), { ".createdAt" => "[now]", ".updatedAt" => "[now]" }, @r###"
        {
          "uid": "dnd_spells",
          "primaryKey": "index",
          "createdAt": "[now]",
          "updatedAt": "[now]"
        }
        "###);

        meili_snap::snapshot_hash!(format!("{:#?}", spells.settings()), @"7917f954b6f345336073bb155540ad6d");
        let documents = spells.documents().unwrap().collect::<Result<Vec<_>>>().unwrap();
        assert_eq!(documents.len(), 10);
        meili_snap::snapshot_hash!(format!("{:#?}", documents), @"235016433dd04262c7f2da01d1e808ce");
    }
}