use std::path::{Path, PathBuf};

use serde::{Deserialize, Serialize, de};

use crate::{
    State,
    install::{InstallPhaseDetails, InstallProgressReporter},
    pack::{
        import::{self, finish_import},
        install_from::{self, CreatePackDescription, PackDependency},
    },
    util::io,
};

// instance.cfg
// https://github.com/PrismLauncher/PrismLauncher/blob/develop/launcher/minecraft/MinecraftInstance.cpp
#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "PascalCase")]
#[serde(untagged)]
enum MMCInstanceEnum {
    General(MMCInstanceGeneral),
    Instance(MMCInstance),
}

#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "PascalCase")]
struct MMCInstanceGeneral {
    pub general: MMCInstance,
}

#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "PascalCase")]
pub struct MMCInstance {
    pub java_path: Option<String>,
    pub jvm_args: Option<String>,

    #[serde(default)]
    #[serde(deserialize_with = "deserialize_optional_bool")]
    pub managed_pack: Option<bool>,

    #[serde(rename = "ManagedPackID")]
    pub managed_pack_id: Option<String>,
    pub managed_pack_type: Option<MMCManagedPackType>,
    #[serde(rename = "ManagedPackVersionID")]
    pub managed_pack_version_id: Option<String>,
    pub managed_pack_version_name: Option<String>,

    #[serde(rename = "iconKey")]
    pub icon_key: Option<String>,
    #[serde(rename = "name")]
    pub name: Option<String>,
}

// serde_ini reads 'true' and 'false' as strings, so we need to convert them to booleans
fn deserialize_optional_bool<'de, D>(
    deserializer: D,
) -> Result<Option<bool>, D::Error>
where
    D: de::Deserializer<'de>,
{
    let s = Option::<String>::deserialize(deserializer)?;
    match s {
        Some(string) => match string.as_str() {
            "true" => Ok(Some(true)),
            "false" => Ok(Some(false)),
            _ => Err(de::Error::custom("expected 'true' or 'false'")),
        },
        None => Ok(None),
    }
}

#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "lowercase")]
pub enum MMCManagedPackType {
    Modrinth,
    Flame,
    ATLauncher,
    #[serde(other)]
    Unknown,
}

// mmc-pack.json
#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "camelCase")]
pub struct MMCPack {
    components: Vec<MMCComponent>,
    format_version: u32,
}

// https://github.com/PrismLauncher/PrismLauncher/blob/develop/launcher/minecraft/Component.h
#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "camelCase")]
pub struct MMCComponent {
    pub uid: String,

    #[serde(default)]
    pub version: Option<String>,
    #[serde(default)]
    pub dependency_only: bool,

    #[serde(default)]
    pub important: bool,
    #[serde(default)]
    pub disabled: bool,

    pub cached_name: Option<String>,
    pub cached_version: Option<String>,

    #[serde(default)]
    pub cached_requires: Vec<MMCComponentRequirement>,
    #[serde(default)]
    pub cached_conflicts: Vec<MMCComponentRequirement>,
}

#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "camelCase")]
pub struct MMCComponentRequirement {
    pub uid: String,
    pub equals_version: Option<String>,
    pub suggests: Option<String>,
}

#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "PascalCase")]
#[serde(untagged)]
enum MMCLauncherEnum {
    General(MMCLauncherGeneral),
    Instance(MMCLauncher),
}

#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "PascalCase")]
struct MMCLauncherGeneral {
    pub general: MMCLauncher,
}

#[derive(Serialize, Deserialize, Debug)]
#[serde(rename_all = "PascalCase")]
pub struct MMCLauncher {
    instance_dir: String,
}

// Checks if if its a folder, and the folder contains instance.cfg and mmc-pack.json, and they both parse
#[tracing::instrument]
pub async fn is_valid_mmc(instance_folder: PathBuf) -> bool {
    let instance_cfg = instance_folder.join("instance.cfg");
    let mmc_pack = instance_folder.join("mmc-pack.json");

    let Ok((mmc_pack, _)) = io::read_any_encoding_to_string(&mmc_pack).await
    else {
        return false;
    };

    load_instance_cfg(&instance_cfg).await.is_ok()
        && serde_json::from_str::<MMCPack>(&mmc_pack).is_ok()
}

#[tracing::instrument]
pub async fn get_instances_subpath(config: PathBuf) -> Option<String> {
    let launcher = io::read_any_encoding_to_string(&config).await.ok()?.0;
    let launcher: MMCLauncherEnum = serde_ini::from_str(&launcher).ok()?;
    match launcher {
        MMCLauncherEnum::General(p) => Some(p.general.instance_dir),
        MMCLauncherEnum::Instance(p) => Some(p.instance_dir),
    }
}

// Loading the INI (instance.cfg) file
async fn load_instance_cfg(file_path: &Path) -> crate::Result<MMCInstance> {
    match serde_ini::from_str::<MMCInstanceEnum>(
        &io::read_any_encoding_to_string(file_path).await?.0,
    )? {
        MMCInstanceEnum::General(instance_cfg) => Ok(instance_cfg.general),
        MMCInstanceEnum::Instance(instance_cfg) => Ok(instance_cfg),
    }
}

// #[tracing::instrument]
pub(crate) async fn import_mmc_instance_dir(
    mmc_instance_path: PathBuf,
    icons_dir: Option<PathBuf>,
    instance_id: &str,
    reporter: InstallProgressReporter,
    details: InstallPhaseDetails,
    symlink: bool,
) -> crate::Result<()> {
    let mmc_pack = serde_json::from_str::<MMCPack>(
        &io::read_any_encoding_to_string(
            &mmc_instance_path.join("mmc-pack.json"),
        )
        .await?
        .0,
    )?;

    let instance_cfg =
        load_instance_cfg(&mmc_instance_path.join("instance.cfg")).await?;

    // Re-cache icon
    let icon = if let Some(icon_key) = instance_cfg.icon_key {
        let mut icon = None;
        for icon_dir in
            icons_dir.iter().chain(std::iter::once(&mmc_instance_path))
        {
            let icon_path = icon_dir.join(&icon_key);
            icon = import::recache_icon(icon_path).await?;
            if icon.is_none() {
                let icon_path = icon_dir.join(format!("{icon_key}.png"));
                icon = import::recache_icon(icon_path).await?;
            }
            if icon.is_some() {
                break;
            }
        }
        icon
    } else {
        None
    };

    // Create description from instance.cfg
    let mut description = CreatePackDescription {
        icon,
        override_title: instance_cfg.name,
        project_id: None,
        version_id: None,
        instance_id: instance_id.to_string(),
        source_filename: None,
    };

    let mut minecraft_folder = mmc_instance_path.join("minecraft");
    if !minecraft_folder.is_dir() {
        minecraft_folder = mmc_instance_path.join(".minecraft");
        if !minecraft_folder.is_dir() {
            return Err(crate::ErrorKind::InputError(
                "Instance is missing Minecraft directory".to_string(),
            )
            .into());
        }
    }

    // Managed pack
    if instance_cfg.managed_pack.unwrap_or(false) {
        match instance_cfg.managed_pack_type {
            Some(MMCManagedPackType::Modrinth) => {
                description.project_id = instance_cfg.managed_pack_id;
                description.version_id = instance_cfg.managed_pack_version_id;

                // Modrinth Managed Pack
                // Kept separate as we may in the future want to add special handling for modrinth managed packs
                import_mmc_unmanaged(instance_id, minecraft_folder, "Imported Modrinth Modpack".to_string(), description, mmc_pack, reporter, details, symlink).await?;
            }
            Some(MMCManagedPackType::Flame | MMCManagedPackType::ATLauncher) => {
                // For flame/atlauncher managed packs
                // Treat as unmanaged, but with 'minecraft' folder instead of '.minecraft'
                import_mmc_unmanaged(instance_id, minecraft_folder, "Imported Modpack".to_string(), description, mmc_pack, reporter, details, symlink).await?;
            },
            Some(_) => {
                // For managed packs that aren't modrinth, flame, atlauncher
                // Treat as unmanaged
                import_mmc_unmanaged(instance_id, minecraft_folder, "ImportedModpack".to_string(), description, mmc_pack, reporter, details, symlink).await?;
            },
            _ => return Err(crate::ErrorKind::InputError("Instance is managed, but managed pack type not specified in instance.cfg".to_string()).into())
        }
    } else {
        // Directly import unmanaged pack
        import_mmc_unmanaged(
            instance_id,
            minecraft_folder,
            "Imported Modpack".to_string(),
            description,
            mmc_pack,
            reporter,
            details,
            symlink,
        )
        .await?;
    }
    Ok(())
}

async fn import_mmc_unmanaged(
    instance_id: &str,
    minecraft_folder: PathBuf,
    backup_name: String,
    description: CreatePackDescription,
    mmc_pack: MMCPack,
    reporter: InstallProgressReporter,
    details: InstallPhaseDetails,
    symlink: bool,
) -> crate::Result<()> {
    let dependencies = mmc_dependencies(&mmc_pack)?;

    install_from::set_instance_information(
        instance_id.to_string(),
        &description,
        &backup_name,
        None,
        &dependencies,
        false,
    )
    .await?;

    // Moves .minecraft folder over (ie: overrides such as resourcepacks, mods, etc)
    let state = State::get().await?;
    finish_import(
        instance_id,
        Some(minecraft_folder),
        None,
        false,
        &state.io_semaphore,
        reporter,
        details,
        symlink,
    )
    .await?;
    Ok(())
}

fn mmc_dependencies(
    mmc_pack: &MMCPack,
) -> crate::Result<std::collections::HashMap<PackDependency, String>> {
    let mut dependencies = std::collections::HashMap::new();
    let has_legacy_fabric = mmc_pack.components.iter().any(|component| {
        component
            .uid
            .to_ascii_lowercase()
            .starts_with("net.legacyfabric")
    });
    let has_cleanroom = mmc_pack.components.iter().any(|component| {
        component
            .uid
            .to_ascii_lowercase()
            .starts_with("com.cleanroommc")
    });
    for component in &mmc_pack.components {
        let uid = component.uid.to_ascii_lowercase();
        if uid.contains("labymod") {
            return Err(crate::ErrorKind::InputError(
				"Unsupported loader LabyMod: Axolotl does not install, update, or repair LabyMod instances"
					.to_string(),
			)
			.into());
        }
        let dependency = if uid.starts_with("net.fabricmc.fabric-loader") {
            Some(if has_legacy_fabric {
                PackDependency::LegacyFabric
            } else {
                PackDependency::FabricLoader
            })
        } else if uid.starts_with("net.legacyfabric") {
            Some(PackDependency::LegacyFabric)
        } else if uid.starts_with("net.minecraftforge") {
            (!has_cleanroom).then_some(PackDependency::Forge)
        } else if uid.starts_with("net.neoforged") {
            Some(PackDependency::NeoForge)
        } else if uid.starts_with("org.quiltmc.quilt-loader") {
            Some(PackDependency::QuiltLoader)
        } else if uid.starts_with("com.cleanroommc") {
            Some(PackDependency::Cleanroom)
        } else if uid.contains("liteloader") {
            Some(PackDependency::LiteLoader)
        } else if uid.contains("optifabric") {
            Some(PackDependency::OptiFabric)
        } else if uid.contains("optifine") {
            Some(PackDependency::OptiFine)
        } else if uid.starts_with("net.minecraft") {
            Some(PackDependency::Minecraft)
        } else {
            None
        };
        if let Some(dependency) = dependency {
            let version = component
                .version
                .clone()
                .filter(|v| !v.is_empty())
                .ok_or_else(|| {
                crate::ErrorKind::InputError(format!(
                    "MultiMC component {} is missing its version",
                    component.uid
                ))
            })?;
            dependencies.insert(dependency, version);
        }
    }
    Ok(dependencies)
}

#[cfg(test)]
mod tests {
    use super::*;

    fn component(uid: &str, version: &str) -> MMCComponent {
        MMCComponent {
            uid: uid.to_string(),
            version: Some(version.to_string()),
            dependency_only: false,
            important: true,
            disabled: false,
            cached_name: None,
            cached_version: None,
            cached_requires: Vec::new(),
            cached_conflicts: Vec::new(),
        }
    }

    #[test]
    fn dependencies_preserve_legacy_fabric_and_optifine_components() {
        let pack = MMCPack {
            format_version: 1,
            components: vec![
                component("net.minecraft", "1.8.9"),
                component("net.legacyfabric.intermediary", "1.8.9"),
                component("net.fabricmc.fabric-loader", "0.13.1.4"),
                component("optifine.OptiFine", "1.8.9_HD_U_M6_pre2"),
                component("optifabric.OptiFabric", "1.13.16"),
            ],
        };
        let dependencies = mmc_dependencies(&pack).unwrap();

        assert_eq!(
            dependencies.get(&PackDependency::LegacyFabric),
            Some(&"0.13.1.4".to_string())
        );
        assert_eq!(
            dependencies.get(&PackDependency::OptiFine),
            Some(&"1.8.9_HD_U_M6_pre2".to_string())
        );
        assert_eq!(
            dependencies.get(&PackDependency::OptiFabric),
            Some(&"1.13.16".to_string())
        );
    }

    #[test]
    fn dependencies_reject_labymod_components() {
        let pack = MMCPack {
            format_version: 1,
            components: vec![component("net.labymod.LabyMod", "4.4.20")],
        };

        assert!(mmc_dependencies(&pack).is_err());
    }
}