pub use git_config::*;
use git_features::threading::OnceCell;

use crate::{bstr::BString, repository::identity, revision::spec, Repository};

pub(crate) mod cache;
mod snapshot;
pub use snapshot::credential_helpers;

///
pub mod overrides;

pub mod tree;
pub use tree::root::Tree;

/// A platform to access configuration values as read from disk.
///
/// Note that these values won't update even if the underlying file(s) change.
pub struct Snapshot<'repo> {
    pub(crate) repo: &'repo Repository,
}

/// A platform to access configuration values and modify them in memory, while making them available when this platform is dropped
/// as form of auto-commit.
/// Note that the values will only affect this instance of the parent repository, and not other clones that may exist.
///
/// Note that these values won't update even if the underlying file(s) change.
///
/// Use [`forget()`][Self::forget()] to not apply any of the changes.
// TODO: make it possible to load snapshots with reloading via .config() and write mutated snapshots back to disk which should be the way
//       to affect all instances of a repo, probably via `config_mut()` and `config_mut_at()`.
pub struct SnapshotMut<'repo> {
    pub(crate) repo: Option<&'repo mut Repository>,
    pub(crate) config: git_config::File<'static>,
}

/// A utility structure created by [`SnapshotMut::commit_auto_rollback()`] that restores the previous configuration on drop.
pub struct CommitAutoRollback<'repo> {
    pub(crate) repo: Option<&'repo mut Repository>,
    pub(crate) prev_config: crate::Config,
}

pub(crate) mod section {
    pub fn is_trusted(meta: &git_config::file::Metadata) -> bool {
        meta.trust == git_sec::Trust::Full || meta.source.kind() != git_config::source::Kind::Repository
    }
}

/// The error returned when failing to initialize the repository configuration.
///
/// This configuration is on the critical path when opening a repository.
#[derive(Debug, thiserror::Error)]
#[allow(missing_docs)]
pub enum Error {
    #[error(transparent)]
    ConfigBoolean(#[from] boolean::Error),
    #[error(transparent)]
    ConfigUnsigned(#[from] unsigned_integer::Error),
    #[error(transparent)]
    ConfigTypedString(#[from] key::GenericErrorWithValue),
    #[error("Cannot handle objects formatted as {:?}", .name)]
    UnsupportedObjectFormat { name: BString },
    #[error(transparent)]
    CoreAbbrev(#[from] abbrev::Error),
    #[error("Could not read configuration file")]
    Io(#[from] std::io::Error),
    #[error(transparent)]
    Init(#[from] git_config::file::init::Error),
    #[error(transparent)]
    ResolveIncludes(#[from] git_config::file::includes::Error),
    #[error(transparent)]
    FromEnv(#[from] git_config::file::init::from_env::Error),
    #[error(transparent)]
    PathInterpolation(#[from] git_config::path::interpolate::Error),
    #[error("{source:?} configuration overrides at open or init time could not be applied.")]
    ConfigOverrides {
        #[source]
        err: overrides::Error,
        source: git_config::Source,
    },
}

///
pub mod diff {
    ///
    pub mod algorithm {
        use crate::bstr::BString;

        /// The error produced when obtaining `diff.algorithm`.
        #[derive(Debug, thiserror::Error)]
        #[allow(missing_docs)]
        pub enum Error {
            #[error("Unknown diff algorithm named '{name}'")]
            Unknown { name: BString },
            #[error("The '{name}' algorithm is not yet implemented")]
            Unimplemented { name: BString },
        }
    }
}

///
pub mod checkout_options {
    /// The error produced when collecting all information needed for checking out files into a worktree.
    #[derive(Debug, thiserror::Error)]
    #[allow(missing_docs)]
    pub enum Error {
        #[error(transparent)]
        ConfigCheckStat(#[from] super::key::GenericErrorWithValue),
        #[error(transparent)]
        ConfigBoolean(#[from] super::boolean::Error),
        #[error(transparent)]
        CheckoutWorkers(#[from] super::checkout::workers::Error),
        #[error("Failed to interpolate the attribute file configured at `core.attributesFile`")]
        AttributesFileInterpolation(#[from] git_config::path::interpolate::Error),
    }
}

///
pub mod protocol {
    ///
    pub mod allow {
        use crate::bstr::BString;

        /// The error returned when obtaining the permission for a particular scheme.
        #[derive(Debug, thiserror::Error)]
        #[allow(missing_docs)]
        #[error("The value {value:?} must be allow|deny|user in configuration key protocol{0}.allow", scheme.as_ref().map(|s| format!(".{s}")).unwrap_or_default())]
        pub struct Error {
            pub scheme: Option<String>,
            pub value: BString,
        }
    }
}

///
pub mod ssh_connect_options {
    /// The error produced when obtaining ssh connection configuration.
    #[derive(Debug, thiserror::Error)]
    #[allow(missing_docs)]
    #[error(transparent)]
    pub struct Error(#[from] super::key::GenericErrorWithValue);
}

///
pub mod key {
    use crate::bstr::BString;

    const fn prefix(kind: char) -> &'static str {
        match kind {
            'n' => "",                         // nothing
            'k' => "The value of key",         // generic key
            't' => "The date format at key",   // time
            'i' => "The timeout at key",       // timeout
            'd' => "The duration [ms] at key", // duration
            'b' => "The boolean at key",       // boolean
            'v' => "The key",                  // generic key with value
            'r' => "The refspec at",           // refspec
            's' => "The ssl version at",       // ssl-version
            'u' => "The url at",               // url
            'w' => "The utf-8 string at",      // string
            _ => panic!("BUG: invalid prefix kind - add a case for it here"),
        }
    }
    const fn suffix(kind: char) -> &'static str {
        match kind {
            'd' => "could not be decoded",                    // decoding
            'i' => "was invalid",                             // invalid
            'u' => "could not be parsed as unsigned integer", // unsigned integer
            'p' => "could not be parsed",                     // parsing
            _ => panic!("BUG: invalid suffix kind - add a case for it here"),
        }
    }
    /// A generic error suitable to produce decent messages for all kinds of configuration errors with config-key granularity.
    ///
    /// This error is meant to be reusable and help produce uniform error messages related to parsing any configuration key.
    #[derive(Debug, thiserror::Error)]
    #[error("{} \"{key}{}\"{} {}", prefix(PREFIX), value.as_ref().map(|v| format!("={v}")).unwrap_or_default(), environment_override.as_deref().map(|var| format!(" (possibly from {var})")).unwrap_or_default(), suffix(SUFFIX))]
    pub struct Error<E: std::error::Error + Send + Sync + 'static, const PREFIX: char, const SUFFIX: char> {
        /// The configuration key that contained the value.
        pub key: BString,
        /// The value that was assigned to `key`.
        pub value: Option<BString>,
        /// The associated environment variable that would override this value.
        pub environment_override: Option<&'static str>,
        /// The source of the error if there was one.
        pub source: Option<E>,
    }

    /// Initialization
    /// Instantiate a new error from the given `key`.
    ///
    /// Note that specifics of the error message are defined by the `PREFIX` and `SUFFIX` which is usually defined by a typedef.
    impl<T, E, const PREFIX: char, const SUFFIX: char> From<&'static T> for Error<E, PREFIX, SUFFIX>
    where
        E: std::error::Error + Send + Sync + 'static,
        T: super::tree::Key,
    {
        fn from(key: &'static T) -> Self {
            Error {
                key: key.logical_name().into(),
                value: None,
                environment_override: key.environment_override(),
                source: None,
            }
        }
    }

    /// Initialization
    impl<E, const PREFIX: char, const SUFFIX: char> Error<E, PREFIX, SUFFIX>
    where
        E: std::error::Error + Send + Sync + 'static,
    {
        /// Instantiate an error with all data from `key` along with the `value` of the key.
        pub fn from_value(key: &'static impl super::tree::Key, value: BString) -> Self {
            Error::from(key).with_value(value)
        }
    }

    /// Builder
    impl<E, const PREFIX: char, const SUFFIX: char> Error<E, PREFIX, SUFFIX>
    where
        E: std::error::Error + Send + Sync + 'static,
    {
        /// Attach the given `err` as source.
        pub fn with_source(mut self, err: E) -> Self {
            self.source = Some(err);
            self
        }

        /// Attach the given `value` as value we observed when the error was produced.
        pub fn with_value(mut self, value: BString) -> Self {
            self.value = Some(value);
            self
        }
    }

    /// A generic key error for use when it doesn't seem worth it say more than 'key is invalid' along with meta-data.
    pub type GenericError<E = git_config::value::Error> = Error<E, 'k', 'i'>;

    /// A generic key error which will also contain a value.
    pub type GenericErrorWithValue<E = git_config::value::Error> = Error<E, 'v', 'i'>;
}

///
pub mod checkout {
    ///
    pub mod workers {
        use crate::config;

        /// The error produced when failing to parse the the `checkout.workers` key.
        pub type Error = config::key::Error<git_config::value::Error, 'n', 'd'>;
    }
}

///
pub mod abbrev {
    use crate::bstr::BString;

    /// The error describing an incorrect `core.abbrev` value.
    #[derive(Debug, thiserror::Error)]
    #[error("Invalid value for 'core.abbrev' = '{}'. It must be between 4 and {}", .value, .max)]
    pub struct Error {
        /// The value found in the git configuration
        pub value: BString,
        /// The maximum abbreviation length, the length of an object hash.
        pub max: u8,
    }
}

///
pub mod remote {
    ///
    pub mod symbolic_name {
        /// The error produced when failing to produce a symbolic remote name from configuration.
        pub type Error = super::super::key::Error<crate::remote::name::Error, 'v', 'i'>;
    }
}

///
pub mod time {
    /// The error produced when failing to parse time from configuration.
    pub type Error = super::key::Error<git_date::parse::Error, 't', 'i'>;
}

///
pub mod lock_timeout {
    /// The error produced when failing to parse timeout for locks.
    pub type Error = super::key::Error<git_config::value::Error, 'i', 'i'>;
}

///
pub mod duration {
    /// The error produced when failing to parse durations (in milliseconds).
    pub type Error = super::key::Error<git_config::value::Error, 'd', 'i'>;
}

///
pub mod boolean {
    /// The error produced when failing to parse time from configuration.
    pub type Error = super::key::Error<git_config::value::Error, 'b', 'i'>;
}

///
pub mod unsigned_integer {
    /// The error produced when failing to parse a signed integer from configuration.
    pub type Error = super::key::Error<git_config::value::Error, 'k', 'u'>;
}

///
pub mod url {
    /// The error produced when failing to parse a url from the configuration.
    pub type Error = super::key::Error<git_url::parse::Error, 'u', 'p'>;
}

///
pub mod string {
    /// The error produced when failing to interpret configuration as UTF-8 encoded string.
    pub type Error = super::key::Error<crate::bstr::Utf8Error, 'w', 'd'>;
}

///
pub mod refspec {
    /// The error produced when failing to parse a refspec from the configuration.
    pub type Error = super::key::Error<git_refspec::parse::Error, 'r', 'p'>;
}

///
pub mod ssl_version {
    /// The error produced when failing to parse a refspec from the configuration.
    pub type Error = super::key::Error<std::convert::Infallible, 's', 'i'>;
}

///
pub mod transport {
    use std::borrow::Cow;

    use crate::bstr::BStr;

    /// The error produced when configuring a transport for a particular protocol.
    #[derive(Debug, thiserror::Error)]
    #[allow(missing_docs)]
    pub enum Error {
        #[error(
            "Could not interpret configuration key {key:?} as {kind} integer of desired range with value: {actual}"
        )]
        InvalidInteger {
            key: &'static str,
            kind: &'static str,
            actual: i64,
        },
        #[error("Could not interpret configuration key {key:?}")]
        ConfigValue {
            source: git_config::value::Error,
            key: &'static str,
        },
        #[error("Could not interpolate path at key {key:?}")]
        InterpolatePath {
            source: git_config::path::interpolate::Error,
            key: &'static str,
        },
        #[error("Could not decode value at key {key:?} as UTF-8 string")]
        IllformedUtf8 {
            key: Cow<'static, BStr>,
            source: crate::config::string::Error,
        },
        #[error("Invalid URL passed for configuration")]
        ParseUrl(#[from] git_url::parse::Error),
        #[error("Could obtain configuration for an HTTP url")]
        Http(#[from] http::Error),
    }

    ///
    pub mod http {
        use std::borrow::Cow;

        use crate::bstr::BStr;

        /// The error produced when configuring a HTTP transport.
        #[derive(Debug, thiserror::Error)]
        #[allow(missing_docs)]
        pub enum Error {
            #[error(transparent)]
            Boolean(#[from] crate::config::boolean::Error),
            #[error(transparent)]
            UnsignedInteger(#[from] crate::config::unsigned_integer::Error),
            #[error(transparent)]
            ConnectTimeout(#[from] crate::config::duration::Error),
            #[error("The proxy authentication at key `{key}` is invalid")]
            InvalidProxyAuthMethod {
                source: crate::config::key::GenericErrorWithValue,
                key: Cow<'static, BStr>,
            },
            #[error("Could not configure the credential helpers for the authenticated proxy url")]
            ConfigureProxyAuthenticate(#[from] crate::config::snapshot::credential_helpers::Error),
            #[error(transparent)]
            InvalidSslVersion(#[from] crate::config::ssl_version::Error),
            #[error("The HTTP version must be 'HTTP/2' or 'HTTP/1.1'")]
            InvalidHttpVersion(#[from] crate::config::key::GenericErrorWithValue),
            #[error("The follow redirects value 'initial', or boolean true or false")]
            InvalidFollowRedirects(#[source] crate::config::key::GenericErrorWithValue),
        }
    }
}

/// Utility type to keep pre-obtained configuration values, only for those required during initial setup
/// and other basic operations that are common enough to warrant a permanent cache.
///
/// All other values are obtained lazily using OnceCell.
#[derive(Clone)]
pub(crate) struct Cache {
    pub resolved: crate::Config,
    /// The hex-length to assume when shortening object ids. If `None`, it should be computed based on the approximate object count.
    pub hex_len: Option<usize>,
    /// true if the repository is designated as 'bare', without work tree.
    pub is_bare: bool,
    /// The type of hash to use.
    pub object_hash: git_hash::Kind,
    /// If true, multi-pack indices, whether present or not, may be used by the object database.
    pub use_multi_pack_index: bool,
    /// The representation of `core.logallrefupdates`, or `None` if the variable wasn't set.
    pub reflog: Option<git_ref::store::WriteReflog>,
    /// The configured user agent for presentation to servers.
    pub(crate) user_agent: OnceCell<String>,
    /// identities for later use, lazy initialization.
    pub(crate) personas: OnceCell<identity::Personas>,
    /// A lazily loaded rewrite list for remote urls
    pub(crate) url_rewrite: OnceCell<crate::remote::url::Rewrite>,
    /// The lazy-loaded rename information for diffs.
    pub(crate) diff_renames: OnceCell<Option<crate::object::tree::diff::Renames>>,
    /// A lazily loaded mapping to know which url schemes to allow
    #[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
    pub(crate) url_scheme: OnceCell<crate::remote::url::SchemePermission>,
    /// The algorithm to use when diffing blobs
    pub(crate) diff_algorithm: OnceCell<git_diff::blob::Algorithm>,
    /// The amount of bytes to use for a memory backed delta pack cache. If `Some(0)`, no cache is used, if `None`
    /// a standard cache is used which costs near to nothing and always pays for itself.
    pub(crate) pack_cache_bytes: Option<usize>,
    /// The amount of bytes to use for caching whole objects, or 0 to turn it off entirely.
    pub(crate) object_cache_bytes: usize,
    /// The config section filter from the options used to initialize this instance. Keep these in sync!
    filter_config_section: fn(&git_config::file::Metadata) -> bool,
    /// The object kind to pick if a prefix is ambiguous.
    pub object_kind_hint: Option<spec::parse::ObjectKindHint>,
    /// If true, we are on a case-insensitive file system.
    pub ignore_case: bool,
    /// If true, we should default what's possible if something is misconfigured, on case by case basis, to be more resilient.
    /// Also available in options! Keep in sync!
    pub lenient_config: bool,
    /// Define how we can use values obtained with `xdg_config(…)` and its `XDG_CONFIG_HOME` variable.
    xdg_config_home_env: git_sec::Permission,
    /// Define how we can use values obtained with `xdg_config(…)`. and its `HOME` variable.
    home_env: git_sec::Permission,
    // TODO: make core.precomposeUnicode available as well.
}