use crate::{
    artifacts::Settings,
    cache::SOLIDITY_FILES_CACHE_FILENAME,
    error::{Result, SolcError, SolcIoError},
    remappings::Remapping,
    resolver::Graph,
    utils, Source, Sources,
};

use crate::artifacts::output_selection::ContractOutputSelection;
use serde::{Deserialize, Serialize};
use std::{
    collections::{BTreeSet, HashSet},
    fmt::{self, Formatter},
    fs,
    path::{Component, Path, PathBuf},
};

/// Where to find all files or where to write them
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ProjectPathsConfig {
    /// Project root
    pub root: PathBuf,
    /// Path to the cache, if any
    pub cache: PathBuf,
    /// Where to store build artifacts
    pub artifacts: PathBuf,
    /// Where to find sources
    pub sources: PathBuf,
    /// Where to find tests
    pub tests: PathBuf,
    /// Where to look for libraries
    pub libraries: Vec<PathBuf>,
    /// The compiler remappings
    pub remappings: Vec<Remapping>,
}

impl ProjectPathsConfig {
    pub fn builder() -> ProjectPathsConfigBuilder {
        ProjectPathsConfigBuilder::default()
    }

    /// Creates a new hardhat style config instance which points to the canonicalized root path
    pub fn hardhat(root: impl AsRef<Path>) -> Result<Self> {
        PathStyle::HardHat.paths(root)
    }

    /// Creates a new dapptools style config instance which points to the canonicalized root path
    pub fn dapptools(root: impl AsRef<Path>) -> Result<Self> {
        PathStyle::Dapptools.paths(root)
    }

    /// Creates a new config with the current directory as the root
    pub fn current_hardhat() -> Result<Self> {
        Self::hardhat(std::env::current_dir().map_err(|err| SolcError::io(err, "."))?)
    }

    /// Creates a new config with the current directory as the root
    pub fn current_dapptools() -> Result<Self> {
        Self::dapptools(std::env::current_dir().map_err(|err| SolcError::io(err, "."))?)
    }

    /// Returns a new [ProjectPaths] instance that contains all directories configured for this
    /// project
    pub fn paths(&self) -> ProjectPaths {
        ProjectPaths {
            artifacts: self.artifacts.clone(),
            sources: self.sources.clone(),
            tests: self.tests.clone(),
            libraries: self.libraries.iter().cloned().collect(),
        }
    }

    /// Same as [Self::paths()] but strips the `root` form all paths,
    /// [ProjectPaths::strip_prefix_all()]
    pub fn paths_relative(&self) -> ProjectPaths {
        let mut paths = self.paths();
        paths.strip_prefix_all(&self.root);
        paths
    }

    /// Creates all configured dirs and files
    pub fn create_all(&self) -> std::result::Result<(), SolcIoError> {
        if let Some(parent) = self.cache.parent() {
            fs::create_dir_all(parent).map_err(|err| SolcIoError::new(err, parent))?;
        }
        fs::create_dir_all(&self.artifacts)
            .map_err(|err| SolcIoError::new(err, &self.artifacts))?;
        fs::create_dir_all(&self.sources).map_err(|err| SolcIoError::new(err, &self.sources))?;
        fs::create_dir_all(&self.tests).map_err(|err| SolcIoError::new(err, &self.tests))?;
        for lib in &self.libraries {
            fs::create_dir_all(lib).map_err(|err| SolcIoError::new(err, lib))?;
        }
        Ok(())
    }

    /// Returns all sources found under the project's configured `sources` path
    pub fn read_sources(&self) -> Result<Sources> {
        tracing::trace!("reading all sources from \"{}\"", self.sources.display());
        Ok(Source::read_all_from(&self.sources)?)
    }

    /// Returns all sources found under the project's configured `test` path
    pub fn read_tests(&self) -> Result<Sources> {
        tracing::trace!("reading all tests from \"{}\"", self.tests.display());
        Ok(Source::read_all_from(&self.tests)?)
    }

    /// Returns the combined set solidity file paths for `Self::sources` and `Self::tests`
    pub fn input_files(&self) -> Vec<PathBuf> {
        utils::source_files(&self.sources)
            .into_iter()
            .chain(utils::source_files(&self.tests))
            .collect()
    }

    /// Returns the combined set of `Self::read_sources` + `Self::read_tests`
    pub fn read_input_files(&self) -> Result<Sources> {
        Ok(Source::read_all_files(self.input_files())?)
    }

    /// Attempts to resolve an `import` from the given working directory.
    ///
    /// The `cwd` path is the parent dir of the file that includes the `import`
    pub fn resolve_import(&self, cwd: &Path, import: &Path) -> Result<PathBuf> {
        let component = import
            .components()
            .next()
            .ok_or_else(|| SolcError::msg(format!("Empty import path {}", import.display())))?;
        if component == Component::CurDir || component == Component::ParentDir {
            // if the import is relative we assume it's already part of the processed input
            // file set
            utils::canonicalize(cwd.join(import)).map_err(|err| {
                SolcError::msg(format!("failed to resolve relative import \"{:?}\"", err))
            })
        } else {
            // resolve library file
            self.resolve_library_import(import.as_ref()).ok_or_else(|| {
                SolcError::msg(format!(
                    "failed to resolve library import \"{:?}\"",
                    import.display()
                ))
            })
        }
    }

    /// Attempts to find the path to the real solidity file that's imported via the given `import`
    /// path by applying the configured remappings and checking the library dirs
    ///
    /// # Example
    ///
    /// Following `@aave` dependency in the `lib` folder `node_modules`
    ///
    /// ```text
    /// <root>/node_modules/@aave
    /// ├── aave-token
    /// │   ├── contracts
    /// │   │   ├── open-zeppelin
    /// │   │   ├── token
    /// ├── governance-v2
    ///     ├── contracts
    ///         ├── interfaces
    /// ```
    ///
    /// has this remapping: `@aave/=@aave/` (name:path) so contracts can be imported as
    ///
    /// ```solidity
    /// import "@aave/governance-v2/contracts/governance/Executor.sol";
    /// ```
    ///
    /// So that `Executor.sol` can be found by checking each `lib` folder (`node_modules`) with
    /// applied remappings. Applying remapping works by checking if the import path of an import
    /// statement starts with the name of a remapping and replacing it with the remapping's `path`.
    ///
    /// There are some caveats though, dapptools style remappings usually include the `src` folder
    /// `ds-test/=lib/ds-test/src/` so that imports look like `import "ds-test/test.sol";` (note the
    /// missing `src` in the import path).
    ///
    /// For hardhat/npm style that's not always the case, most notably for [openzeppelin-contracts](https://github.com/OpenZeppelin/openzeppelin-contracts) if installed via npm.
    /// The remapping is detected as `'@openzeppelin/=node_modules/@openzeppelin/contracts/'`, which
    /// includes the source directory `contracts`, however it's common to see import paths like:
    ///
    /// `import "@openzeppelin/contracts/token/ERC20/IERC20.sol";`
    ///
    /// instead of
    ///
    /// `import "@openzeppelin/token/ERC20/IERC20.sol";`
    ///
    /// There is no strict rule behind this, but because [`crate::remappings::Remapping::find_many`]
    /// returns `'@openzeppelin/=node_modules/@openzeppelin/contracts/'` we should handle the
    /// case if the remapping path ends with `contracts` and the import path starts with
    /// `<remapping name>/contracts`. Otherwise we can end up with a resolved path that has a
    /// duplicate `contracts` segment:
    /// `@openzeppelin/contracts/contracts/token/ERC20/IERC20.sol` we check for this edge case
    /// here so that both styles work out of the box.
    pub fn resolve_library_import(&self, import: &Path) -> Option<PathBuf> {
        // if the import path starts with the name of the remapping then we get the resolved path by
        // removing the name and adding the remainder to the path of the remapping
        if let Some(path) = self.remappings.iter().find_map(|r| {
            import.strip_prefix(&r.name).ok().map(|stripped_import| {
                let lib_path = Path::new(&r.path).join(stripped_import);

                // we handle the edge case where the path of a remapping ends with "contracts"
                // (`<name>/=.../contracts`) and the stripped import also starts with `contracts`
                if let Ok(adjusted_import) = stripped_import.strip_prefix("contracts/") {
                    if r.path.ends_with("contracts/") && !lib_path.exists() {
                        return Path::new(&r.path).join(adjusted_import)
                    }
                }
                lib_path
            })
        }) {
            Some(self.root.join(path))
        } else {
            utils::resolve_library(&self.libraries, import)
        }
    }

    /// Attempts to autodetect the artifacts directory based on the given root path
    ///
    /// Dapptools layout takes precedence over hardhat style.
    /// This will return:
    ///   - `<root>/out` if it exists or `<root>/artifacts` does not exist,
    ///   - `<root>/artifacts` if it exists and `<root>/out` does not exist.
    pub fn find_artifacts_dir(root: impl AsRef<Path>) -> PathBuf {
        utils::find_fave_or_alt_path(root, "out", "artifacts")
    }

    /// Attempts to autodetect the source directory based on the given root path
    ///
    /// Dapptools layout takes precedence over hardhat style.
    /// This will return:
    ///   - `<root>/src` if it exists or `<root>/contracts` does not exist,
    ///   - `<root>/contracts` if it exists and `<root>/src` does not exist.
    pub fn find_source_dir(root: impl AsRef<Path>) -> PathBuf {
        utils::find_fave_or_alt_path(root, "src", "contracts")
    }

    /// Attempts to autodetect the lib directory based on the given root path
    ///
    /// Dapptools layout takes precedence over hardhat style.
    /// This will return:
    ///   - `<root>/lib` if it exists or `<root>/node_modules` does not exist,
    ///   - `<root>/node_modules` if it exists and `<root>/lib` does not exist.
    pub fn find_libs(root: impl AsRef<Path>) -> Vec<PathBuf> {
        vec![utils::find_fave_or_alt_path(root, "lib", "node_modules")]
    }

    /// Flattens all file imports into a single string
    pub fn flatten(&self, target: &Path) -> Result<String> {
        tracing::trace!("flattening file");
        let graph = Graph::resolve(self)?;
        self.flatten_node(target, &graph, &mut Default::default(), false, false)
    }

    /// Flattens a single node from the dependency graph
    fn flatten_node(
        &self,
        target: &Path,
        graph: &Graph,
        imported: &mut HashSet<usize>,
        strip_version_pragma: bool,
        strip_license: bool,
    ) -> Result<String> {
        let target_dir = target.parent().ok_or_else(|| {
            SolcError::msg(format!("failed to get parent directory for \"{:?}\"", target.display()))
        })?;
        let target_index = graph.files().get(target).ok_or_else(|| {
            SolcError::msg(format!("cannot resolve file at \"{:?}\"", target.display()))
        })?;

        if imported.contains(target_index) {
            // short circuit nodes that were already imported, if both A.sol and B.sol import C.sol
            return Ok(String::new())
        }
        imported.insert(*target_index);

        let target_node = graph.node(*target_index);

        let mut imports = target_node.imports().clone();
        imports.sort_by_key(|x| x.loc().0);

        let mut content = target_node.content().as_bytes().to_vec();
        let mut offset = 0_isize;

        if strip_license {
            if let Some(license) = target_node.license() {
                let (start, end) = license.loc_by_offset(offset);
                content.splice(start..end, std::iter::empty());
                offset -= (end - start) as isize;
            }
        }

        if strip_version_pragma {
            if let Some(version) = target_node.version() {
                let (start, end) = version.loc_by_offset(offset);
                content.splice(start..end, std::iter::empty());
                offset -= (end - start) as isize;
            }
        }

        for import in imports.iter() {
            let import_path = self.resolve_import(target_dir, import.data())?;
            let s = self.flatten_node(&import_path, graph, imported, true, true)?;
            let import_content = s.trim().as_bytes();
            let import_content_len = import_content.len() as isize;
            let (start, end) = import.loc_by_offset(offset);
            content.splice(start..end, import_content.iter().copied());
            offset += import_content_len - ((end - start) as isize);
        }

        let result = String::from_utf8(content).map_err(|err| {
            SolcError::msg(format!("failed to convert extended bytes to string: {}", err))
        })?;

        Ok(result)
    }
}

impl fmt::Display for ProjectPathsConfig {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        writeln!(f, "root: {}", self.root.display())?;
        writeln!(f, "contracts: {}", self.sources.display())?;
        writeln!(f, "artifacts: {}", self.artifacts.display())?;
        writeln!(f, "tests: {}", self.tests.display())?;
        writeln!(f, "libs:")?;
        for lib in &self.libraries {
            writeln!(f, "    {}", lib.display())?;
        }
        writeln!(f, "remappings:")?;
        for remapping in &self.remappings {
            writeln!(f, "    {}", remapping)?;
        }
        Ok(())
    }
}

/// This is a subset of [ProjectPathsConfig] that contains all relevant folders in the project
#[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
pub struct ProjectPaths {
    pub artifacts: PathBuf,
    pub sources: PathBuf,
    pub tests: PathBuf,
    pub libraries: BTreeSet<PathBuf>,
}

impl ProjectPaths {
    /// Joins the folders' location with `root`
    pub fn join_all(&mut self, root: impl AsRef<Path>) -> &mut Self {
        let root = root.as_ref();
        self.artifacts = root.join(&self.artifacts);
        self.sources = root.join(&self.sources);
        self.tests = root.join(&self.tests);
        let libraries = std::mem::take(&mut self.libraries);
        self.libraries.extend(libraries.into_iter().map(|p| root.join(p)));
        self
    }

    /// Removes `base` from all folders
    pub fn strip_prefix_all(&mut self, base: impl AsRef<Path>) -> &mut Self {
        let base = base.as_ref();

        if let Ok(prefix) = self.artifacts.strip_prefix(base) {
            self.artifacts = prefix.to_path_buf();
        }
        if let Ok(prefix) = self.sources.strip_prefix(base) {
            self.sources = prefix.to_path_buf();
        }
        if let Ok(prefix) = self.tests.strip_prefix(base) {
            self.tests = prefix.to_path_buf();
        }
        let libraries = std::mem::take(&mut self.libraries);
        self.libraries.extend(
            libraries
                .into_iter()
                .map(|p| p.strip_prefix(base).map(|p| p.to_path_buf()).unwrap_or(p)),
        );
        self
    }
}

impl Default for ProjectPaths {
    fn default() -> Self {
        Self {
            artifacts: "out".into(),
            sources: "src".into(),
            tests: "tests".into(),
            libraries: Default::default(),
        }
    }
}

#[derive(Debug, Clone, Eq, PartialEq)]
pub enum PathStyle {
    HardHat,
    Dapptools,
}

impl PathStyle {
    /// Convert into a `ProjectPathsConfig` given the root path and based on the styled
    pub fn paths(&self, root: impl AsRef<Path>) -> Result<ProjectPathsConfig> {
        let root = root.as_ref();
        let root = utils::canonicalize(root)?;

        Ok(match self {
            PathStyle::Dapptools => ProjectPathsConfig::builder()
                .sources(root.join("src"))
                .artifacts(root.join("out"))
                .lib(root.join("lib"))
                .remappings(Remapping::find_many(&root.join("lib")))
                .root(root)
                .build()?,
            PathStyle::HardHat => ProjectPathsConfig::builder()
                .sources(root.join("contracts"))
                .artifacts(root.join("artifacts"))
                .lib(root.join("node_modules"))
                .root(root)
                .build()?,
        })
    }
}

#[derive(Debug, Clone, Default)]
pub struct ProjectPathsConfigBuilder {
    root: Option<PathBuf>,
    cache: Option<PathBuf>,
    artifacts: Option<PathBuf>,
    sources: Option<PathBuf>,
    tests: Option<PathBuf>,
    libraries: Option<Vec<PathBuf>>,
    remappings: Option<Vec<Remapping>>,
}

impl ProjectPathsConfigBuilder {
    pub fn root(mut self, root: impl Into<PathBuf>) -> Self {
        self.root = Some(utils::canonicalized(root));
        self
    }

    pub fn cache(mut self, cache: impl Into<PathBuf>) -> Self {
        self.cache = Some(utils::canonicalized(cache));
        self
    }

    pub fn artifacts(mut self, artifacts: impl Into<PathBuf>) -> Self {
        self.artifacts = Some(utils::canonicalized(artifacts));
        self
    }

    pub fn sources(mut self, sources: impl Into<PathBuf>) -> Self {
        self.sources = Some(utils::canonicalized(sources));
        self
    }

    pub fn tests(mut self, tests: impl Into<PathBuf>) -> Self {
        self.tests = Some(utils::canonicalized(tests));
        self
    }

    /// Specifically disallow additional libraries
    pub fn no_libs(mut self) -> Self {
        self.libraries = Some(Vec::new());
        self
    }

    pub fn lib(mut self, lib: impl Into<PathBuf>) -> Self {
        self.libraries.get_or_insert_with(Vec::new).push(utils::canonicalized(lib));
        self
    }

    pub fn libs(mut self, libs: impl IntoIterator<Item = impl Into<PathBuf>>) -> Self {
        let libraries = self.libraries.get_or_insert_with(Vec::new);
        for lib in libs.into_iter() {
            libraries.push(utils::canonicalized(lib));
        }
        self
    }

    pub fn remapping(mut self, remapping: Remapping) -> Self {
        self.remappings.get_or_insert_with(Vec::new).push(remapping);
        self
    }

    pub fn remappings(mut self, remappings: impl IntoIterator<Item = Remapping>) -> Self {
        let our_remappings = self.remappings.get_or_insert_with(Vec::new);
        for remapping in remappings.into_iter() {
            our_remappings.push(remapping);
        }
        self
    }

    pub fn build_with_root(self, root: impl Into<PathBuf>) -> ProjectPathsConfig {
        let root = utils::canonicalized(root);

        let libraries = self.libraries.unwrap_or_else(|| ProjectPathsConfig::find_libs(&root));

        ProjectPathsConfig {
            cache: self
                .cache
                .unwrap_or_else(|| root.join("cache").join(SOLIDITY_FILES_CACHE_FILENAME)),
            artifacts: self
                .artifacts
                .unwrap_or_else(|| ProjectPathsConfig::find_artifacts_dir(&root)),
            sources: self.sources.unwrap_or_else(|| ProjectPathsConfig::find_source_dir(&root)),
            tests: self.tests.unwrap_or_else(|| root.join("tests")),
            remappings: self
                .remappings
                .unwrap_or_else(|| libraries.iter().flat_map(Remapping::find_many).collect()),
            libraries,
            root,
        }
    }

    pub fn build(self) -> std::result::Result<ProjectPathsConfig, SolcIoError> {
        let root = self
            .root
            .clone()
            .map(Ok)
            .unwrap_or_else(std::env::current_dir)
            .map_err(|err| SolcIoError::new(err, "."))?;
        Ok(self.build_with_root(root))
    }
}

/// The config to use when compiling the contracts
#[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
pub struct SolcConfig {
    /// How the file was compiled
    pub settings: Settings,
}

impl SolcConfig {
    /// # Example
    ///
    /// Autodetect solc version and default settings
    ///
    /// ```rust
    /// use ethers_solc::SolcConfig;
    /// let config = SolcConfig::builder().build();
    /// ```
    pub fn builder() -> SolcConfigBuilder {
        SolcConfigBuilder::default()
    }
}

impl From<SolcConfig> for Settings {
    fn from(config: SolcConfig) -> Self {
        config.settings
    }
}

#[derive(Default)]
pub struct SolcConfigBuilder {
    settings: Option<Settings>,

    /// additionally selected outputs that should be included in the `Contract` that `solc´ creates
    output_selection: Vec<ContractOutputSelection>,
}

impl SolcConfigBuilder {
    pub fn settings(mut self, settings: Settings) -> Self {
        self.settings = Some(settings);
        self
    }

    /// Adds another `ContractOutputSelection` to the set
    #[must_use]
    pub fn additional_output(mut self, output: impl Into<ContractOutputSelection>) -> Self {
        self.output_selection.push(output.into());
        self
    }

    /// Adds multiple `ContractOutputSelection` to the set
    #[must_use]
    pub fn additional_outputs<I, S>(mut self, outputs: I) -> Self
    where
        I: IntoIterator<Item = S>,
        S: Into<ContractOutputSelection>,
    {
        for out in outputs {
            self = self.additional_output(out);
        }
        self
    }

    /// Creates the solc config
    ///
    /// If no solc version is configured then it will be determined by calling `solc --version`.
    pub fn build(self) -> SolcConfig {
        let Self { settings, output_selection } = self;
        let mut settings = settings.unwrap_or_default();
        settings.push_all(output_selection);
        SolcConfig { settings }
    }
}

/// Helper struct for serializing `--allow-paths` arguments to Solc
///
/// From the [Solc docs](https://docs.soliditylang.org/en/v0.8.9/using-the-compiler.html#base-path-and-import-remapping):
/// For security reasons the compiler has restrictions on what directories it can access.
/// Directories of source files specified on the command line and target paths of
/// remappings are automatically allowed to be accessed by the file reader,
/// but everything else is rejected by default. Additional paths (and their subdirectories)
/// can be allowed via the --allow-paths /sample/path,/another/sample/path switch.
/// Everything inside the path specified via --base-path is always allowed.
#[derive(Clone, Debug, Default)]
pub struct AllowedLibPaths(pub(crate) Vec<PathBuf>);

impl AllowedLibPaths {
    pub fn is_empty(&self) -> bool {
        self.0.is_empty()
    }
}

impl fmt::Display for AllowedLibPaths {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let lib_paths = self
            .0
            .iter()
            .filter(|path| path.exists())
            .map(|path| format!("{}", path.display()))
            .collect::<Vec<_>>()
            .join(",");
        write!(f, "{}", lib_paths)
    }
}

impl<T: Into<PathBuf>> From<Vec<T>> for AllowedLibPaths {
    fn from(libs: Vec<T>) -> Self {
        let libs = libs.into_iter().map(utils::canonicalized).collect();
        AllowedLibPaths(libs)
    }
}

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

    #[test]
    fn can_autodetect_dirs() {
        let root = crate::utils::tempdir("root").unwrap();
        let out = root.path().join("out");
        let artifacts = root.path().join("artifacts");
        let contracts = root.path().join("contracts");
        let src = root.path().join("src");
        let lib = root.path().join("lib");
        let node_modules = root.path().join("node_modules");

        let root = root.path();
        assert_eq!(ProjectPathsConfig::find_source_dir(root), src,);
        std::fs::File::create(&contracts).unwrap();
        assert_eq!(ProjectPathsConfig::find_source_dir(root), contracts,);
        assert_eq!(
            ProjectPathsConfig::builder().build_with_root(&root).sources,
            utils::canonicalized(contracts),
        );
        std::fs::File::create(&src).unwrap();
        assert_eq!(ProjectPathsConfig::find_source_dir(root), src,);
        assert_eq!(
            ProjectPathsConfig::builder().build_with_root(&root).sources,
            utils::canonicalized(src),
        );

        assert_eq!(ProjectPathsConfig::find_artifacts_dir(root), out,);
        std::fs::File::create(&artifacts).unwrap();
        assert_eq!(ProjectPathsConfig::find_artifacts_dir(root), artifacts,);
        assert_eq!(
            ProjectPathsConfig::builder().build_with_root(&root).artifacts,
            utils::canonicalized(artifacts),
        );
        std::fs::File::create(&out).unwrap();
        assert_eq!(ProjectPathsConfig::find_artifacts_dir(root), out,);
        assert_eq!(
            ProjectPathsConfig::builder().build_with_root(&root).artifacts,
            utils::canonicalized(out),
        );

        assert_eq!(ProjectPathsConfig::find_libs(root), vec![lib.clone()],);
        std::fs::File::create(&node_modules).unwrap();
        assert_eq!(ProjectPathsConfig::find_libs(root), vec![node_modules.clone()],);
        assert_eq!(
            ProjectPathsConfig::builder().build_with_root(&root).libraries,
            vec![utils::canonicalized(node_modules)],
        );
        std::fs::File::create(&lib).unwrap();
        assert_eq!(ProjectPathsConfig::find_libs(root), vec![lib.clone()],);
        assert_eq!(
            ProjectPathsConfig::builder().build_with_root(&root).libraries,
            vec![utils::canonicalized(lib)],
        );
    }
}