//! Output artifact handling

use crate::{
    artifacts::{
        contract::{CompactContract, CompactContractBytecode, Contract},
        BytecodeObject, CompactBytecode, CompactContractBytecodeCow, CompactDeployedBytecode,
        FileToContractsMap, SourceFile,
    },
    compile::output::{contracts::VersionedContracts, sources::VersionedSourceFiles},
    error::Result,
    sourcemap::{SourceMap, SyntaxError},
    sources::VersionedSourceFile,
    utils, HardhatArtifact, ProjectPathsConfig, SolFilesCache, SolcError, SolcIoError,
};
use ethers_core::{abi::Abi, types::Bytes};
use semver::Version;
use serde::{de::DeserializeOwned, Deserialize, Serialize};
use std::{
    borrow::Cow,
    collections::{btree_map::BTreeMap, HashSet},
    ffi::OsString,
    fmt, fs,
    hash::Hash,
    io,
    ops::Deref,
    path::{Path, PathBuf},
};
use tracing::{error, trace};

mod configurable;
pub(crate) mod files;

use crate::files::MappedContract;
pub use configurable::*;

/// Represents unique artifact metadata for identifying artifacts on output
#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Serialize, Deserialize)]
pub struct ArtifactId {
    /// `artifact` cache path
    pub path: PathBuf,
    pub name: String,
    /// Original source file path
    pub source: PathBuf,
    /// `solc` version that produced this artifact
    pub version: Version,
}

impl ArtifactId {
    /// Converts any `\\` separators in the `path` to `/`
    pub fn slash_paths(&mut self) {
        #[cfg(windows)]
        {
            use path_slash::PathBufExt;
            self.path = self.path.to_slash_lossy().as_ref().into();
            self.source = self.source.to_slash_lossy().as_ref().into();
        }
    }

    /// Convenience function fo [`Self::slash_paths()`]
    pub fn with_slashed_paths(mut self) -> Self {
        self.slash_paths();
        self
    }

    /// Returns a `<filename>:<name>` slug that identifies an artifact
    ///
    /// Note: This identifier is not necessarily unique. If two contracts have the same name, they
    /// will share the same slug. For a unique identifier see [ArtifactId::identifier].
    pub fn slug(&self) -> String {
        format!("{}.json:{}", self.path.file_stem().unwrap().to_string_lossy(), self.name)
    }

    /// Returns a `<source path>:<name>` slug that uniquely identifies an artifact
    pub fn identifier(&self) -> String {
        format!("{}:{}", self.source.to_string_lossy(), self.name)
    }

    /// Returns a `<filename><version>:<name>` slug that identifies an artifact
    pub fn slug_versioned(&self) -> String {
        format!(
            "{}.{}.{}.{}.json:{}",
            self.path.file_stem().unwrap().to_string_lossy(),
            self.version.major,
            self.version.minor,
            self.version.patch,
            self.name
        )
    }
}

/// Represents an artifact file representing a [`crate::Contract`]
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ArtifactFile<T> {
    /// The Artifact that was written
    pub artifact: T,
    /// path to the file where the `artifact` was written to
    pub file: PathBuf,
    /// `solc` version that produced this artifact
    pub version: Version,
}

impl<T: Serialize> ArtifactFile<T> {
    /// Writes the given contract to the `out` path creating all parent directories
    pub fn write(&self) -> Result<()> {
        trace!("writing artifact file {:?} {}", self.file, self.version);
        utils::create_parent_dir_all(&self.file)?;
        fs::write(&self.file, serde_json::to_vec_pretty(&self.artifact)?)
            .map_err(|err| SolcError::io(err, &self.file))?;
        Ok(())
    }
}

impl<T> ArtifactFile<T> {
    /// Sets the file to `root` adjoined to `self.file`.
    pub fn join(&mut self, root: impl AsRef<Path>) {
        self.file = root.as_ref().join(&self.file);
    }

    /// Removes `base` from the artifact's path
    pub fn strip_prefix(&mut self, base: impl AsRef<Path>) {
        if let Ok(prefix) = self.file.strip_prefix(base) {
            self.file = prefix.to_path_buf();
        }
    }
}

/// local helper type alias `file name -> (contract name  -> Vec<..>)`
pub(crate) type ArtifactsMap<T> = FileToContractsMap<Vec<ArtifactFile<T>>>;

/// Represents a set of Artifacts
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Artifacts<T>(pub ArtifactsMap<T>);

impl<T> From<ArtifactsMap<T>> for Artifacts<T> {
    fn from(m: ArtifactsMap<T>) -> Self {
        Self(m)
    }
}

impl<'a, T> IntoIterator for &'a Artifacts<T> {
    type Item = (&'a String, &'a BTreeMap<String, Vec<ArtifactFile<T>>>);
    type IntoIter =
        std::collections::btree_map::Iter<'a, String, BTreeMap<String, Vec<ArtifactFile<T>>>>;

    fn into_iter(self) -> Self::IntoIter {
        self.0.iter()
    }
}

impl<T> IntoIterator for Artifacts<T> {
    type Item = (String, BTreeMap<String, Vec<ArtifactFile<T>>>);
    type IntoIter =
        std::collections::btree_map::IntoIter<String, BTreeMap<String, Vec<ArtifactFile<T>>>>;

    fn into_iter(self) -> Self::IntoIter {
        self.0.into_iter()
    }
}

impl<T> Default for Artifacts<T> {
    fn default() -> Self {
        Self(Default::default())
    }
}

impl<T> AsRef<ArtifactsMap<T>> for Artifacts<T> {
    fn as_ref(&self) -> &ArtifactsMap<T> {
        &self.0
    }
}

impl<T> AsMut<ArtifactsMap<T>> for Artifacts<T> {
    fn as_mut(&mut self) -> &mut ArtifactsMap<T> {
        &mut self.0
    }
}

impl<T> Deref for Artifacts<T> {
    type Target = ArtifactsMap<T>;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl<T: Serialize> Artifacts<T> {
    /// Writes all artifacts into the given `artifacts_root` folder
    pub fn write_all(&self) -> Result<()> {
        for artifact in self.artifact_files() {
            artifact.write()?;
        }
        Ok(())
    }
}

impl<T> Artifacts<T> {
    /// Converts all `\\` separators in _all_ paths to `/`
    pub fn slash_paths(&mut self) {
        #[cfg(windows)]
        {
            use path_slash::PathExt;
            self.0 = std::mem::take(&mut self.0)
                .into_iter()
                .map(|(path, files)| (Path::new(&path).to_slash_lossy().to_string(), files))
                .collect()
        }
    }

    pub fn into_inner(self) -> ArtifactsMap<T> {
        self.0
    }

    /// Sets the artifact files location to `root` adjoined to `self.file`.
    pub fn join_all(&mut self, root: impl AsRef<Path>) -> &mut Self {
        let root = root.as_ref();
        self.artifact_files_mut().for_each(|artifact| artifact.join(root));
        self
    }

    /// Removes `base` from all artifacts
    pub fn strip_prefix_all(&mut self, base: impl AsRef<Path>) -> &mut Self {
        let base = base.as_ref();
        self.artifact_files_mut().for_each(|artifact| artifact.strip_prefix(base));
        self
    }

    /// Returns all `ArtifactFile`s for the contract with the matching name
    fn get_contract_artifact_files(&self, contract_name: &str) -> Option<&Vec<ArtifactFile<T>>> {
        self.0.values().find_map(|all| all.get(contract_name))
    }

    /// Returns the `Artifact` with matching file, contract name and version
    pub fn find_artifact(
        &self,
        file: &str,
        contract_name: &str,
        version: &Version,
    ) -> Option<&ArtifactFile<T>> {
        self.0
            .get(file)
            .and_then(|contracts| contracts.get(contract_name))
            .and_then(|artifacts| artifacts.iter().find(|artifact| artifact.version == *version))
    }

    /// Returns true if this type contains an artifact with the given path for the given contract
    pub fn has_contract_artifact(&self, contract_name: &str, artifact_path: &Path) -> bool {
        self.get_contract_artifact_files(contract_name)
            .map(|artifacts| artifacts.iter().any(|artifact| artifact.file == artifact_path))
            .unwrap_or_default()
    }

    /// Returns true if this type contains an artifact with the given path
    pub fn has_artifact(&self, artifact_path: &Path) -> bool {
        self.artifact_files().any(|artifact| artifact.file == artifact_path)
    }

    /// Iterate over all artifact files
    pub fn artifact_files(&self) -> impl Iterator<Item = &ArtifactFile<T>> {
        self.0.values().flat_map(|c| c.values().flat_map(|artifacts| artifacts.iter()))
    }
    /// Iterate over all artifact files
    pub fn artifact_files_mut(&mut self) -> impl Iterator<Item = &mut ArtifactFile<T>> {
        self.0.values_mut().flat_map(|c| c.values_mut().flat_map(|artifacts| artifacts.iter_mut()))
    }

    /// Returns an iterator over _all_ artifacts and `<file name:contract name>`
    pub fn into_artifacts<O: ArtifactOutput<Artifact = T>>(
        self,
    ) -> impl Iterator<Item = (ArtifactId, T)> {
        self.0.into_iter().flat_map(|(file, contract_artifacts)| {
            contract_artifacts.into_iter().flat_map(move |(_contract_name, artifacts)| {
                let source = PathBuf::from(file.clone());
                artifacts.into_iter().filter_map(move |artifact| {
                    O::contract_name(&artifact.file).map(|name| {
                        (
                            ArtifactId {
                                path: PathBuf::from(&artifact.file),
                                name,
                                source: source.clone(),
                                version: artifact.version,
                            }
                            .with_slashed_paths(),
                            artifact.artifact,
                        )
                    })
                })
            })
        })
    }

    /// Returns an iterator that yields the tuple `(file, contract name, artifact)`
    ///
    /// **NOTE** this returns the path as is
    pub fn into_artifacts_with_files(self) -> impl Iterator<Item = (String, String, T)> {
        self.0.into_iter().flat_map(|(f, contract_artifacts)| {
            contract_artifacts.into_iter().flat_map(move |(name, artifacts)| {
                let contract_name = name;
                let file = f.clone();
                artifacts
                    .into_iter()
                    .map(move |artifact| (file.clone(), contract_name.clone(), artifact.artifact))
            })
        })
    }

    /// Strips the given prefix from all artifact file paths to make them relative to the given
    /// `root` argument
    pub fn into_stripped_file_prefixes(self, base: impl AsRef<Path>) -> Self {
        let base = base.as_ref();
        let artifacts = self
            .0
            .into_iter()
            .map(|(file, c)| {
                let file_path = Path::new(&file);
                if let Ok(p) = file_path.strip_prefix(base) {
                    (p.to_string_lossy().to_string(), c)
                } else {
                    (file, c)
                }
            })
            .collect();

        Artifacts(artifacts)
    }

    /// Finds the first artifact `T` with a matching contract name
    pub fn find_first(&self, contract_name: impl AsRef<str>) -> Option<&T> {
        let contract_name = contract_name.as_ref();
        self.0.iter().find_map(|(_file, contracts)| {
            contracts.get(contract_name).and_then(|c| c.get(0).map(|a| &a.artifact))
        })
    }

    ///  Finds the artifact with matching path and name
    pub fn find(&self, path: impl AsRef<str>, contract: impl AsRef<str>) -> Option<&T> {
        let contract_path = path.as_ref();
        let contract_name = contract.as_ref();
        self.0.iter().filter(|(path, _)| path.as_str() == contract_path).find_map(
            |(_file, contracts)| {
                contracts.get(contract_name).and_then(|c| c.get(0).map(|a| &a.artifact))
            },
        )
    }

    /// Removes the artifact with matching file and name
    pub fn remove(&mut self, path: impl AsRef<str>, contract: impl AsRef<str>) -> Option<T> {
        let contract_path = path.as_ref();
        let contract_name = contract.as_ref();
        self.0.iter_mut().filter(|(path, _)| path.as_str() == contract_path).find_map(
            |(_file, contracts)| {
                let mut artifact = None;
                if let Some((c, mut artifacts)) = contracts.remove_entry(contract_name) {
                    if !artifacts.is_empty() {
                        artifact = Some(artifacts.remove(0).artifact);
                    }
                    if !artifacts.is_empty() {
                        contracts.insert(c, artifacts);
                    }
                }
                artifact
            },
        )
    }

    /// Removes the first artifact `T` with a matching contract name
    ///
    /// *Note:* if there are multiple artifacts (contract compiled with different solc) then this
    /// returns the first artifact in that set
    pub fn remove_first(&mut self, contract_name: impl AsRef<str>) -> Option<T> {
        let contract_name = contract_name.as_ref();
        self.0.iter_mut().find_map(|(_file, contracts)| {
            let mut artifact = None;
            if let Some((c, mut artifacts)) = contracts.remove_entry(contract_name) {
                if !artifacts.is_empty() {
                    artifact = Some(artifacts.remove(0).artifact);
                }
                if !artifacts.is_empty() {
                    contracts.insert(c, artifacts);
                }
            }
            artifact
        })
    }
}

/// A trait representation for a [`crate::Contract`] artifact
pub trait Artifact {
    /// Returns the artifact's `Abi` and bytecode
    fn into_inner(self) -> (Option<Abi>, Option<Bytes>);

    /// Turns the artifact into a container type for abi, compact bytecode and deployed bytecode
    fn into_compact_contract(self) -> CompactContract;

    /// Turns the artifact into a container type for abi, full bytecode and deployed bytecode
    fn into_contract_bytecode(self) -> CompactContractBytecode;

    /// Returns the contents of this type as a single tuple of abi, bytecode and deployed bytecode
    fn into_parts(self) -> (Option<Abi>, Option<Bytes>, Option<Bytes>);

    /// Consumes the type and returns the [Abi]
    fn into_abi(self) -> Option<Abi>
    where
        Self: Sized,
    {
        self.into_parts().0
    }

    /// Consumes the type and returns the `bytecode`
    fn into_bytecode_bytes(self) -> Option<Bytes>
    where
        Self: Sized,
    {
        self.into_parts().1
    }
    /// Consumes the type and returns the `deployed bytecode`
    fn into_deployed_bytecode_bytes(self) -> Option<Bytes>
    where
        Self: Sized,
    {
        self.into_parts().2
    }

    /// Same as [`Self::into_parts()`] but returns `Err` if an element is `None`
    fn try_into_parts(self) -> Result<(Abi, Bytes, Bytes)>
    where
        Self: Sized,
    {
        let (abi, bytecode, deployed_bytecode) = self.into_parts();

        Ok((
            abi.ok_or_else(|| SolcError::msg("abi missing"))?,
            bytecode.ok_or_else(|| SolcError::msg("bytecode missing"))?,
            deployed_bytecode.ok_or_else(|| SolcError::msg("deployed bytecode missing"))?,
        ))
    }

    /// Returns the reference of container type for abi, compact bytecode and deployed bytecode if
    /// available
    fn get_contract_bytecode(&self) -> CompactContractBytecodeCow;

    /// Returns the reference to the `bytecode`
    fn get_bytecode(&self) -> Option<Cow<CompactBytecode>> {
        self.get_contract_bytecode().bytecode
    }

    /// Returns the reference to the `bytecode` object
    fn get_bytecode_object(&self) -> Option<Cow<BytecodeObject>> {
        let val = match self.get_bytecode()? {
            Cow::Borrowed(b) => Cow::Borrowed(&b.object),
            Cow::Owned(b) => Cow::Owned(b.object),
        };
        Some(val)
    }

    /// Returns the bytes of the `bytecode` object
    fn get_bytecode_bytes(&self) -> Option<Cow<Bytes>> {
        let val = match self.get_bytecode_object()? {
            Cow::Borrowed(b) => Cow::Borrowed(b.as_bytes()?),
            Cow::Owned(b) => Cow::Owned(b.into_bytes()?),
        };
        Some(val)
    }

    /// Returns the reference to the `deployedBytecode`
    fn get_deployed_bytecode(&self) -> Option<Cow<CompactDeployedBytecode>> {
        self.get_contract_bytecode().deployed_bytecode
    }

    /// Returns the reference to the `bytecode` object
    fn get_deployed_bytecode_object(&self) -> Option<Cow<BytecodeObject>> {
        let val = match self.get_deployed_bytecode()? {
            Cow::Borrowed(b) => Cow::Borrowed(&b.bytecode.as_ref()?.object),
            Cow::Owned(b) => Cow::Owned(b.bytecode?.object),
        };
        Some(val)
    }

    /// Returns the bytes of the `deployed bytecode` object
    fn get_deployed_bytecode_bytes(&self) -> Option<Cow<Bytes>> {
        let val = match self.get_deployed_bytecode_object()? {
            Cow::Borrowed(b) => Cow::Borrowed(b.as_bytes()?),
            Cow::Owned(b) => Cow::Owned(b.into_bytes()?),
        };
        Some(val)
    }

    /// Returns the reference to the [Abi] if available
    fn get_abi(&self) -> Option<Cow<Abi>> {
        self.get_contract_bytecode().abi
    }

    /// Returns the `sourceMap` of the creation bytecode
    ///
    /// Returns `None` if no `sourceMap` string was included in the compiler output
    /// Returns `Some(Err)` if parsing the sourcemap failed
    fn get_source_map(&self) -> Option<std::result::Result<SourceMap, SyntaxError>> {
        self.get_bytecode()?.source_map()
    }

    /// Returns the creation bytecode `sourceMap` as str if it was included in the compiler output
    fn get_source_map_str(&self) -> Option<Cow<str>> {
        match self.get_bytecode()? {
            Cow::Borrowed(code) => code.source_map.as_deref().map(Cow::Borrowed),
            Cow::Owned(code) => code.source_map.map(Cow::Owned),
        }
    }

    /// Returns the `sourceMap` of the runtime bytecode
    ///
    /// Returns `None` if no `sourceMap` string was included in the compiler output
    /// Returns `Some(Err)` if parsing the sourcemap failed
    fn get_source_map_deployed(&self) -> Option<std::result::Result<SourceMap, SyntaxError>> {
        self.get_deployed_bytecode()?.source_map()
    }

    /// Returns the runtime bytecode `sourceMap` as str if it was included in the compiler output
    fn get_source_map_deployed_str(&self) -> Option<Cow<str>> {
        match self.get_bytecode()? {
            Cow::Borrowed(code) => code.source_map.as_deref().map(Cow::Borrowed),
            Cow::Owned(code) => code.source_map.map(Cow::Owned),
        }
    }
}

impl<T> Artifact for T
where
    T: Into<CompactContractBytecode> + Into<CompactContract>,
    for<'a> &'a T: Into<CompactContractBytecodeCow<'a>>,
{
    fn into_inner(self) -> (Option<Abi>, Option<Bytes>) {
        let artifact = self.into_compact_contract();
        (artifact.abi, artifact.bin.and_then(|bin| bin.into_bytes()))
    }

    fn into_compact_contract(self) -> CompactContract {
        self.into()
    }

    fn into_contract_bytecode(self) -> CompactContractBytecode {
        self.into()
    }

    fn into_parts(self) -> (Option<Abi>, Option<Bytes>, Option<Bytes>) {
        self.into_compact_contract().into_parts()
    }

    fn get_contract_bytecode(&self) -> CompactContractBytecodeCow {
        self.into()
    }
}

/// Handler invoked with the output of `solc`
///
/// Implementers of this trait are expected to take care of [`crate::Contract`] to
/// [`crate::ArtifactOutput::Artifact`] conversion and how that `Artifact` type is stored on disk,
/// this includes artifact file location and naming.
///
/// Depending on the [`crate::Project`] contracts and their compatible versions,
/// The project compiler may invoke different `solc` executables on the same
/// solidity file leading to multiple [`crate::CompilerOutput`]s for the same `.sol` file.
/// In addition to the `solidity file` to `contract` relationship (1-N*)
/// [`crate::VersionedContracts`] also tracks the `contract` to (`artifact` + `solc version`)
/// relationship (1-N+).
pub trait ArtifactOutput {
    /// Represents the artifact that will be stored for a `Contract`
    type Artifact: Artifact + DeserializeOwned + Serialize + fmt::Debug + Send + Sync;

    /// Handle the aggregated set of compiled contracts from the solc [`crate::CompilerOutput`].
    ///
    /// This will be invoked with all aggregated contracts from (multiple) solc `CompilerOutput`.
    /// See [`crate::AggregatedCompilerOutput`]
    fn on_output(
        &self,
        contracts: &VersionedContracts,
        sources: &VersionedSourceFiles,
        layout: &ProjectPathsConfig,
        ctx: OutputContext,
    ) -> Result<Artifacts<Self::Artifact>> {
        let mut artifacts = self.output_to_artifacts(contracts, sources, ctx, layout);
        fs::create_dir_all(&layout.artifacts).map_err(|err| {
            error!(dir=?layout.artifacts, "Failed to create artifacts folder");
            SolcIoError::new(err, &layout.artifacts)
        })?;

        artifacts.join_all(&layout.artifacts);
        artifacts.write_all()?;

        self.write_extras(contracts, &artifacts)?;

        Ok(artifacts)
    }

    /// Write additional files for the contract
    fn write_contract_extras(&self, contract: &Contract, file: &Path) -> Result<()> {
        ExtraOutputFiles::all().write_extras(contract, file)
    }

    /// Writes additional files for the contracts if the included in the `Contract`, such as `ir`,
    /// `ewasm`, `iropt`.
    ///
    /// By default, these fields are _not_ enabled in the [`crate::artifacts::Settings`], see
    /// [`crate::artifacts::output_selection::OutputSelection::default_output_selection()`], and the
    /// respective fields of the [`Contract`] will `None`. If they'll be manually added to the
    /// `output_selection`, then we're also creating individual files for this output, such as
    /// `Greeter.iropt`, `Gretter.ewasm`
    fn write_extras(
        &self,
        contracts: &VersionedContracts,
        artifacts: &Artifacts<Self::Artifact>,
    ) -> Result<()> {
        for (file, contracts) in contracts.as_ref().iter() {
            for (name, versioned_contracts) in contracts {
                for c in versioned_contracts {
                    if let Some(artifact) = artifacts.find_artifact(file, name, &c.version) {
                        let file = &artifact.file;
                        utils::create_parent_dir_all(file)?;
                        self.write_contract_extras(&c.contract, file)?;
                    }
                }
            }
        }

        Ok(())
    }

    /// Returns the file name for the contract's artifact
    /// `Greeter.json`
    fn output_file_name(name: impl AsRef<str>) -> PathBuf {
        format!("{}.json", name.as_ref()).into()
    }

    /// Returns the file name for the contract's artifact and the given version
    /// `Greeter.0.8.11.json`
    fn output_file_name_versioned(name: impl AsRef<str>, version: &Version) -> PathBuf {
        format!("{}.{}.{}.{}.json", name.as_ref(), version.major, version.minor, version.patch)
            .into()
    }

    /// Returns the appropriate file name for the conflicting file.
    ///
    /// This should ensure that the resulting `PathBuf` is conflict free, which could be possible if
    /// there are two separate contract files (in different folders) that contain the same contract:
    ///
    /// `src/A.sol::A`
    /// `src/nested/A.sol::A`
    ///
    /// Which would result in the same `PathBuf` if only the file and contract name is taken into
    /// account, [`Self::output_file`].
    ///
    /// This return a unique output file
    fn conflict_free_output_file(
        already_taken: &HashSet<PathBuf>,
        conflict: PathBuf,
        contract_file: impl AsRef<Path>,
        artifacts_folder: impl AsRef<Path>,
    ) -> PathBuf {
        let artifacts_folder = artifacts_folder.as_ref();
        let mut rel_candidate = conflict;
        if let Ok(stripped) = rel_candidate.strip_prefix(artifacts_folder) {
            rel_candidate = stripped.to_path_buf();
        }
        #[allow(clippy::redundant_clone)] // false positive
        let mut candidate = rel_candidate.clone();
        let contract_file = contract_file.as_ref();
        let mut current_parent = contract_file.parent();

        while let Some(parent_name) = current_parent.and_then(|f| f.file_name()) {
            // this is problematic if both files are absolute
            candidate = Path::new(parent_name).join(&candidate);
            let out_path = artifacts_folder.join(&candidate);
            if !already_taken.contains(&out_path) {
                trace!("found alternative output file={:?} for {:?}", out_path, contract_file);
                return out_path
            }
            current_parent = current_parent.and_then(|f| f.parent());
        }

        // this means we haven't found an alternative yet, which shouldn't actually happen since
        // `contract_file` are unique, but just to be safe, handle this case in which case
        // we simply numerate the parent folder

        trace!("no conflict free output file found after traversing the file");

        let mut num = 1;

        loop {
            // this will attempt to find an alternate path by numerating the first component in the
            // path: `<root>+_<num>/....sol`
            let mut components = rel_candidate.components();
            let first = components.next().expect("path not empty");
            let name = first.as_os_str();
            let mut numerated = OsString::with_capacity(name.len() + 2);
            numerated.push(name);
            numerated.push("_");
            numerated.push(num.to_string());

            let candidate: PathBuf = Some(numerated.as_os_str())
                .into_iter()
                .chain(components.map(|c| c.as_os_str()))
                .collect();
            if !already_taken.contains(&candidate) {
                trace!("found alternative output file={:?} for {:?}", candidate, contract_file);
                return candidate
            }

            num += 1;
        }
    }

    /// Returns the path to the contract's artifact location based on the contract's file and name
    ///
    /// This returns `contract.sol/contract.json` by default
    fn output_file(contract_file: impl AsRef<Path>, name: impl AsRef<str>) -> PathBuf {
        let name = name.as_ref();
        contract_file
            .as_ref()
            .file_name()
            .map(Path::new)
            .map(|p| p.join(Self::output_file_name(name)))
            .unwrap_or_else(|| Self::output_file_name(name))
    }

    /// Returns the path to the contract's artifact location based on the contract's file, name and
    /// version
    ///
    /// This returns `contract.sol/contract.0.8.11.json` by default
    fn output_file_versioned(
        contract_file: impl AsRef<Path>,
        name: impl AsRef<str>,
        version: &Version,
    ) -> PathBuf {
        let name = name.as_ref();
        contract_file
            .as_ref()
            .file_name()
            .map(Path::new)
            .map(|p| p.join(Self::output_file_name_versioned(name, version)))
            .unwrap_or_else(|| Self::output_file_name_versioned(name, version))
    }

    /// The inverse of `contract_file_name`
    ///
    /// Expected to return the solidity contract's name derived from the file path
    /// `sources/Greeter.sol` -> `Greeter`
    fn contract_name(file: impl AsRef<Path>) -> Option<String> {
        file.as_ref().file_stem().and_then(|s| s.to_str().map(|s| s.to_string()))
    }

    /// Whether the corresponding artifact of the given contract file and name exists
    fn output_exists(
        contract_file: impl AsRef<Path>,
        name: impl AsRef<str>,
        root: impl AsRef<Path>,
    ) -> bool {
        root.as_ref().join(Self::output_file(contract_file, name)).exists()
    }

    /// Read the artifact that's stored at the given path
    ///
    /// # Errors
    ///
    /// Returns an error if
    ///     - The file does not exist
    ///     - The file's content couldn't be deserialized into the `Artifact` type
    fn read_cached_artifact(path: impl AsRef<Path>) -> Result<Self::Artifact> {
        let path = path.as_ref();
        let file = fs::File::open(path).map_err(|err| SolcError::io(err, path))?;
        let file = io::BufReader::new(file);
        Ok(serde_json::from_reader(file)?)
    }

    /// Read the cached artifacts that are located the paths the iterator yields
    ///
    /// See [`Self::read_cached_artifact()`]
    fn read_cached_artifacts<T, I>(files: I) -> Result<BTreeMap<PathBuf, Self::Artifact>>
    where
        I: IntoIterator<Item = T>,
        T: Into<PathBuf>,
    {
        let mut artifacts = BTreeMap::default();
        for path in files.into_iter() {
            let path = path.into();
            let artifact = Self::read_cached_artifact(&path)?;
            artifacts.insert(path, artifact);
        }
        Ok(artifacts)
    }

    /// Convert a contract to the artifact type
    ///
    /// This is the core conversion function that takes care of converting a `Contract` into the
    /// associated `Artifact` type.
    /// The `SourceFile` is also provided
    fn contract_to_artifact(
        &self,
        _file: &str,
        _name: &str,
        contract: Contract,
        source_file: Option<&SourceFile>,
    ) -> Self::Artifact;

    /// Convert the compiler output into a set of artifacts
    ///
    /// **Note:** This does only convert, but _NOT_ write the artifacts to disk, See
    /// [`Self::on_output()`]
    fn output_to_artifacts(
        &self,
        contracts: &VersionedContracts,
        sources: &VersionedSourceFiles,
        ctx: OutputContext,
        layout: &ProjectPathsConfig,
    ) -> Artifacts<Self::Artifact> {
        let mut artifacts = ArtifactsMap::new();

        // this tracks all the `SourceFile`s that we successfully mapped to a contract
        let mut non_standalone_sources = HashSet::new();

        // this holds all output files and the contract(s) it belongs to
        let artifact_files = contracts.artifact_files::<Self>(&ctx);

        // this tracks the final artifacts, which we use as lookup for checking conflicts when
        // converting stand-alone artifacts in the next step
        let mut final_artifact_paths = HashSet::new();

        for contracts in artifact_files.files.into_values() {
            for (idx, mapped_contract) in contracts.iter().enumerate() {
                let MappedContract { file, name, contract, artifact_path } = mapped_contract;
                // track `SourceFile`s that can be mapped to contracts
                let source_file = sources.find_file_and_version(file, &contract.version);

                if let Some(source) = source_file {
                    non_standalone_sources.insert((source.id, &contract.version));
                }

                let mut artifact_path = artifact_path.clone();

                if contracts.len() > 1 {
                    // naming conflict where the `artifact_path` belongs to two conflicting
                    // contracts need to adjust the paths properly

                    // we keep the top most conflicting file unchanged
                    let is_top_most =
                        contracts.iter().enumerate().filter(|(i, _)| *i != idx).all(|(_, c)| {
                            Path::new(file).components().count() <
                                Path::new(c.file).components().count()
                        });
                    if !is_top_most {
                        // we resolve the conflicting by finding a new unique, alternative path
                        artifact_path = Self::conflict_free_output_file(
                            &final_artifact_paths,
                            artifact_path,
                            file,
                            &layout.artifacts,
                        );
                    }
                }

                final_artifact_paths.insert(artifact_path.clone());

                let artifact =
                    self.contract_to_artifact(file, name, contract.contract.clone(), source_file);

                let artifact = ArtifactFile {
                    artifact,
                    file: artifact_path,
                    version: contract.version.clone(),
                };

                artifacts
                    .entry(file.to_string())
                    .or_default()
                    .entry(name.to_string())
                    .or_default()
                    .push(artifact);
            }
        }

        // extend with standalone source files and convert them to artifacts
        // this is unfortunately necessary, so we can "mock" `Artifacts` for solidity files without
        // any contract definition, which are not included in the `CompilerOutput` but we want to
        // create Artifacts for them regardless
        for (file, sources) in sources.as_ref().iter() {
            for source in sources {
                if !non_standalone_sources.contains(&(source.source_file.id, &source.version)) {
                    // scan the ast as a safe measure to ensure this file does not include any
                    // source units
                    // there's also no need to create a standalone artifact for source files that
                    // don't contain an ast
                    if source.source_file.contains_contract_definition() ||
                        source.source_file.ast.is_none()
                    {
                        continue
                    }

                    // we use file and file stem
                    if let Some(name) = Path::new(file).file_stem().and_then(|stem| stem.to_str()) {
                        if let Some(artifact) =
                            self.standalone_source_file_to_artifact(file, source)
                        {
                            let mut artifact_path = if sources.len() > 1 {
                                Self::output_file_versioned(file, name, &source.version)
                            } else {
                                Self::output_file(file, name)
                            };

                            if final_artifact_paths.contains(&artifact_path) {
                                // preventing conflict
                                artifact_path = Self::conflict_free_output_file(
                                    &final_artifact_paths,
                                    artifact_path,
                                    file,
                                    &layout.artifacts,
                                );
                                final_artifact_paths.insert(artifact_path.clone());
                            }

                            let entries = artifacts
                                .entry(file.to_string())
                                .or_default()
                                .entry(name.to_string())
                                .or_default();

                            if entries.iter().all(|entry| entry.version != source.version) {
                                entries.push(ArtifactFile {
                                    artifact,
                                    file: artifact_path,
                                    version: source.version.clone(),
                                });
                            }
                        }
                    }
                }
            }
        }

        Artifacts(artifacts)
    }

    /// This converts a `SourceFile` that doesn't contain _any_ contract definitions (interfaces,
    /// contracts, libraries) to an artifact.
    ///
    /// We do this because not all `SourceFile`s emitted by solc have at least 1 corresponding entry
    /// in the `contracts`
    /// section of the solc output. For example for an `errors.sol` that only contains custom error
    /// definitions and no contract, no `Contract` object will be generated by solc. However, we
    /// still want to emit an `Artifact` for that file that may include the `ast`, docs etc.,
    /// because other tools depend on this, such as slither.
    fn standalone_source_file_to_artifact(
        &self,
        _path: &str,
        _file: &VersionedSourceFile,
    ) -> Option<Self::Artifact>;
}

/// Additional context to use during [`ArtifactOutput::on_output()`]
#[derive(Debug, Clone, Default)]
#[non_exhaustive]
pub struct OutputContext<'a> {
    /// Cache file of the project or empty if no caching is enabled
    ///
    /// This context is required for partially cached recompile with conflicting files, so that we
    /// can use the same adjusted output path for conflicting files like:
    ///
    /// ```text
    /// src
    /// ├── a.sol
    /// └── inner
    ///     └── a.sol
    /// ```
    pub cache: Cow<'a, SolFilesCache>,
}

// === impl OutputContext

impl<'a> OutputContext<'a> {
    /// Create a new context with the given cache file
    pub fn new(cache: &'a SolFilesCache) -> Self {
        Self { cache: Cow::Borrowed(cache) }
    }

    /// Returns the path of the already existing artifact for the `contract` of the `file` compiled
    /// with the `version`.
    ///
    /// Returns `None` if no file exists
    pub fn existing_artifact(
        &self,
        file: impl AsRef<Path>,
        contract: &str,
        version: &Version,
    ) -> Option<&PathBuf> {
        self.cache.entry(file)?.find_artifact(contract, version)
    }
}

/// An `Artifact` implementation that uses a compact representation
///
/// Creates a single json artifact with
/// ```json
///  {
///    "abi": [],
///    "bytecode": {...},
///    "deployedBytecode": {...}
///  }
/// ```
#[derive(Debug, Copy, Clone, Eq, PartialEq, Default)]
pub struct MinimalCombinedArtifacts {
    _priv: (),
}

impl ArtifactOutput for MinimalCombinedArtifacts {
    type Artifact = CompactContractBytecode;

    fn contract_to_artifact(
        &self,
        _file: &str,
        _name: &str,
        contract: Contract,
        _source_file: Option<&SourceFile>,
    ) -> Self::Artifact {
        Self::Artifact::from(contract)
    }

    fn standalone_source_file_to_artifact(
        &self,
        _path: &str,
        _file: &VersionedSourceFile,
    ) -> Option<Self::Artifact> {
        None
    }
}

/// An Artifacts handler implementation that works the same as `MinimalCombinedArtifacts` but also
/// supports reading hardhat artifacts if an initial attempt to deserialize an artifact failed
#[derive(Debug, Copy, Clone, Eq, PartialEq, Default)]
pub struct MinimalCombinedArtifactsHardhatFallback {
    _priv: (),
}

impl ArtifactOutput for MinimalCombinedArtifactsHardhatFallback {
    type Artifact = CompactContractBytecode;

    fn on_output(
        &self,
        output: &VersionedContracts,
        sources: &VersionedSourceFiles,
        layout: &ProjectPathsConfig,
        ctx: OutputContext,
    ) -> Result<Artifacts<Self::Artifact>> {
        MinimalCombinedArtifacts::default().on_output(output, sources, layout, ctx)
    }

    fn read_cached_artifact(path: impl AsRef<Path>) -> Result<Self::Artifact> {
        let path = path.as_ref();
        let content = fs::read_to_string(path).map_err(|err| SolcError::io(err, path))?;
        if let Ok(a) = serde_json::from_str(&content) {
            Ok(a)
        } else {
            error!("Failed to deserialize compact artifact");
            trace!("Fallback to hardhat artifact deserialization");
            let artifact = serde_json::from_str::<HardhatArtifact>(&content)?;
            trace!("successfully deserialized hardhat artifact");
            Ok(artifact.into_contract_bytecode())
        }
    }

    fn contract_to_artifact(
        &self,
        file: &str,
        name: &str,
        contract: Contract,
        source_file: Option<&SourceFile>,
    ) -> Self::Artifact {
        MinimalCombinedArtifacts::default().contract_to_artifact(file, name, contract, source_file)
    }

    fn standalone_source_file_to_artifact(
        &self,
        path: &str,
        file: &VersionedSourceFile,
    ) -> Option<Self::Artifact> {
        MinimalCombinedArtifacts::default().standalone_source_file_to_artifact(path, file)
    }
}

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

    #[test]
    fn is_artifact() {
        fn assert_artifact<T: Artifact>() {}

        assert_artifact::<CompactContractBytecode>();
        assert_artifact::<serde_json::Value>();
    }

    #[test]
    fn can_find_alternate_paths() {
        let mut already_taken = HashSet::new();

        let file = "v1/tokens/Greeter.sol";
        let conflict = PathBuf::from("out/Greeter.sol/Greeter.json");

        let alternative = ConfigurableArtifacts::conflict_free_output_file(
            &already_taken,
            conflict.clone(),
            file,
            "out",
        );
        assert_eq!(alternative, PathBuf::from("out/tokens/Greeter.sol/Greeter.json"));

        already_taken.insert("out/tokens/Greeter.sol/Greeter.json".into());
        let alternative = ConfigurableArtifacts::conflict_free_output_file(
            &already_taken,
            conflict.clone(),
            file,
            "out",
        );
        assert_eq!(alternative, PathBuf::from("out/v1/tokens/Greeter.sol/Greeter.json"));

        already_taken.insert("out/v1/tokens/Greeter.sol/Greeter.json".into());
        let alternative =
            ConfigurableArtifacts::conflict_free_output_file(&already_taken, conflict, file, "out");
        assert_eq!(alternative, PathBuf::from("Greeter.sol_1/Greeter.json"));
    }

    #[test]
    fn can_find_alternate_path_conflict() {
        let mut already_taken = HashSet::new();

        let file = "/Users/carter/dev/goldfinch/mono/packages/protocol/test/forge/mainnet/utils/BaseMainnetForkingTest.t.sol";
        let conflict = PathBuf::from("/Users/carter/dev/goldfinch/mono/packages/protocol/artifacts/BaseMainnetForkingTest.t.sol/BaseMainnetForkingTest.json");
        already_taken.insert("/Users/carter/dev/goldfinch/mono/packages/protocol/artifacts/BaseMainnetForkingTest.t.sol/BaseMainnetForkingTest.json".into());

        let alternative = ConfigurableArtifacts::conflict_free_output_file(
            &already_taken,
            conflict,
            file,
            "/Users/carter/dev/goldfinch/mono/packages/protocol/artifacts",
        );

        assert_eq!(alternative, PathBuf::from("/Users/carter/dev/goldfinch/mono/packages/protocol/artifacts/utils/BaseMainnetForkingTest.t.sol/BaseMainnetForkingTest.json"));
    }
}