use std::sync::Arc;

use uv_pep440::{Version, VersionParseError};

use crate::{MarkerValueString, MarkerValueVersion, StringVersion};

/// The marker values for a python interpreter, normally the current one
///
/// <https://packaging.python.org/en/latest/specifications/dependency-specifiers/#environment-markers>
///
/// Some are `(String, Version)` because we have to support version comparison
#[allow(missing_docs, clippy::unsafe_derive_deserialize)]
#[derive(Clone, Debug, Eq, Hash, PartialEq, serde::Deserialize, serde::Serialize)]
pub struct MarkerEnvironment {
    #[serde(flatten)]
    inner: Arc<MarkerEnvironmentInner>,
}

#[derive(Clone, Debug, Eq, Hash, PartialEq, serde::Deserialize, serde::Serialize)]
struct MarkerEnvironmentInner {
    implementation_name: String,
    implementation_version: StringVersion,
    os_name: String,
    platform_machine: String,
    platform_python_implementation: String,
    platform_release: String,
    platform_system: String,
    platform_version: String,
    python_full_version: StringVersion,
    python_version: StringVersion,
    sys_platform: String,
}

impl MarkerEnvironment {
    /// Returns of the PEP 440 version typed value of the key in the current environment
    pub fn get_version(&self, key: &MarkerValueVersion) -> &Version {
        match key {
            MarkerValueVersion::ImplementationVersion => &self.implementation_version().version,
            MarkerValueVersion::PythonFullVersion => &self.python_full_version().version,
            MarkerValueVersion::PythonVersion => &self.python_version().version,
        }
    }

    /// Returns of the stringly typed value of the key in the current environment
    pub fn get_string(&self, key: &MarkerValueString) -> &str {
        match key {
            MarkerValueString::ImplementationName => self.implementation_name(),
            MarkerValueString::OsName | MarkerValueString::OsNameDeprecated => self.os_name(),
            MarkerValueString::PlatformMachine | MarkerValueString::PlatformMachineDeprecated => {
                self.platform_machine()
            }
            MarkerValueString::PlatformPythonImplementation
            | MarkerValueString::PlatformPythonImplementationDeprecated
            | MarkerValueString::PythonImplementationDeprecated => {
                self.platform_python_implementation()
            }
            MarkerValueString::PlatformRelease => self.platform_release(),
            MarkerValueString::PlatformSystem => self.platform_system(),
            MarkerValueString::PlatformVersion | MarkerValueString::PlatformVersionDeprecated => {
                self.platform_version()
            }
            MarkerValueString::SysPlatform | MarkerValueString::SysPlatformDeprecated => {
                self.sys_platform()
            }
        }
    }
}

/// APIs for retrieving specific parts of a marker environment.
impl MarkerEnvironment {
    /// Returns the name of the Python implementation for this environment.
    ///
    /// This is equivalent to `sys.implementation.name`.
    ///
    /// Some example values are: `cpython`.
    #[inline]
    pub fn implementation_name(&self) -> &str {
        &self.inner.implementation_name
    }

    /// Returns the Python implementation version for this environment.
    ///
    /// This value is derived from `sys.implementation.version`. See [PEP 508
    /// environment markers] for full details.
    ///
    /// This is equivalent to `sys.implementation.name`.
    ///
    /// Some example values are: `3.4.0`, `3.5.0b1`.
    ///
    /// [PEP 508 environment markers]: https://peps.python.org/pep-0508/#environment-markers
    #[inline]
    pub fn implementation_version(&self) -> &StringVersion {
        &self.inner.implementation_version
    }

    /// Returns the name of the operating system for this environment.
    ///
    /// This is equivalent to `os.name`.
    ///
    /// Some example values are: `posix`, `java`.
    #[inline]
    pub fn os_name(&self) -> &str {
        &self.inner.os_name
    }

    /// Returns the name of the machine for this environment's platform.
    ///
    /// This is equivalent to `platform.machine()`.
    ///
    /// Some example values are: `x86_64`.
    #[inline]
    pub fn platform_machine(&self) -> &str {
        &self.inner.platform_machine
    }

    /// Returns the name of the Python implementation for this environment's
    /// platform.
    ///
    /// This is equivalent to `platform.python_implementation()`.
    ///
    /// Some example values are: `CPython`, `Jython`.
    #[inline]
    pub fn platform_python_implementation(&self) -> &str {
        &self.inner.platform_python_implementation
    }

    /// Returns the release for this environment's platform.
    ///
    /// This is equivalent to `platform.release()`.
    ///
    /// Some example values are: `3.14.1-x86_64-linode39`, `14.5.0`, `1.8.0_51`.
    #[inline]
    pub fn platform_release(&self) -> &str {
        &self.inner.platform_release
    }

    /// Returns the system for this environment's platform.
    ///
    /// This is equivalent to `platform.system()`.
    ///
    /// Some example values are: `Linux`, `Windows`, `Java`.
    #[inline]
    pub fn platform_system(&self) -> &str {
        &self.inner.platform_system
    }

    /// Returns the version for this environment's platform.
    ///
    /// This is equivalent to `platform.version()`.
    ///
    /// Some example values are: `#1 SMP Fri Apr 25 13:07:35 EDT 2014`,
    /// `Java HotSpot(TM) 64-Bit Server VM, 25.51-b03, Oracle Corporation`,
    /// `Darwin Kernel Version 14.5.0: Wed Jul 29 02:18:53 PDT 2015;
    /// root:xnu-2782.40.9~2/RELEASE_X86_64`.
    #[inline]
    pub fn platform_version(&self) -> &str {
        &self.inner.platform_version
    }

    /// Returns the full version of Python for this environment.
    ///
    /// This is equivalent to `platform.python_version()`.
    ///
    /// Some example values are: `3.4.0`, `3.5.0b1`.
    #[inline]
    pub fn python_full_version(&self) -> &StringVersion {
        &self.inner.python_full_version
    }

    /// Returns the version of Python for this environment.
    ///
    /// This is equivalent to `'.'.join(platform.python_version_tuple()[:2])`.
    ///
    /// Some example values are: `3.4`, `2.7`.
    #[inline]
    pub fn python_version(&self) -> &StringVersion {
        &self.inner.python_version
    }

    /// Returns the name of the system platform for this environment.
    ///
    /// This is equivalent to `sys.platform`.
    ///
    /// Some example values are: `linux`, `linux2`, `darwin`, `java1.8.0_51`
    /// (note that `linux` is from Python3 and `linux2` from Python2).
    #[inline]
    pub fn sys_platform(&self) -> &str {
        &self.inner.sys_platform
    }
}

/// APIs for setting specific parts of a marker environment.
impl MarkerEnvironment {
    /// Set the name of the Python implementation for this environment.
    ///
    /// See also [`MarkerEnvironment::implementation_name`].
    #[inline]
    #[must_use]
    pub fn with_implementation_name(mut self, value: impl Into<String>) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).implementation_name = value.into();
        self
    }

    /// Set the Python implementation version for this environment.
    ///
    /// See also [`MarkerEnvironment::implementation_version`].
    #[inline]
    #[must_use]
    pub fn with_implementation_version(
        mut self,
        value: impl Into<StringVersion>,
    ) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).implementation_version = value.into();
        self
    }

    /// Set the name of the operating system for this environment.
    ///
    /// See also [`MarkerEnvironment::os_name`].
    #[inline]
    #[must_use]
    pub fn with_os_name(mut self, value: impl Into<String>) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).os_name = value.into();
        self
    }

    /// Set the name of the machine for this environment's platform.
    ///
    /// See also [`MarkerEnvironment::platform_machine`].
    #[inline]
    #[must_use]
    pub fn with_platform_machine(mut self, value: impl Into<String>) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).platform_machine = value.into();
        self
    }

    /// Set the name of the Python implementation for this environment's
    /// platform.
    ///
    /// See also [`MarkerEnvironment::platform_python_implementation`].
    #[inline]
    #[must_use]
    pub fn with_platform_python_implementation(
        mut self,
        value: impl Into<String>,
    ) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).platform_python_implementation = value.into();
        self
    }

    /// Set the release for this environment's platform.
    ///
    /// See also [`MarkerEnvironment::platform_release`].
    #[inline]
    #[must_use]
    pub fn with_platform_release(mut self, value: impl Into<String>) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).platform_release = value.into();
        self
    }

    /// Set the system for this environment's platform.
    ///
    /// See also [`MarkerEnvironment::platform_system`].
    #[inline]
    #[must_use]
    pub fn with_platform_system(mut self, value: impl Into<String>) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).platform_system = value.into();
        self
    }

    /// Set the version for this environment's platform.
    ///
    /// See also [`MarkerEnvironment::platform_version`].
    #[inline]
    #[must_use]
    pub fn with_platform_version(mut self, value: impl Into<String>) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).platform_version = value.into();
        self
    }

    /// Set the full version of Python for this environment.
    ///
    /// See also [`MarkerEnvironment::python_full_version`].
    #[inline]
    #[must_use]
    pub fn with_python_full_version(
        mut self,
        value: impl Into<StringVersion>,
    ) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).python_full_version = value.into();
        self
    }

    /// Set the version of Python for this environment.
    ///
    /// See also [`MarkerEnvironment::python_full_version`].
    #[inline]
    #[must_use]
    pub fn with_python_version(mut self, value: impl Into<StringVersion>) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).python_version = value.into();
        self
    }

    /// Set the name of the system platform for this environment.
    ///
    /// See also [`MarkerEnvironment::sys_platform`].
    #[inline]
    #[must_use]
    pub fn with_sys_platform(mut self, value: impl Into<String>) -> MarkerEnvironment {
        Arc::make_mut(&mut self.inner).sys_platform = value.into();
        self
    }
}

/// A builder for constructing a marker environment.
///
/// A value of this type can be fallibly converted to a full
/// [`MarkerEnvironment`] via [`MarkerEnvironment::try_from`]. This can fail when
/// the version strings given aren't valid.
///
/// The main utility of this type is for constructing dummy or test environment
/// values.
#[allow(missing_docs)]
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub struct MarkerEnvironmentBuilder<'a> {
    pub implementation_name: &'a str,
    pub implementation_version: &'a str,
    pub os_name: &'a str,
    pub platform_machine: &'a str,
    pub platform_python_implementation: &'a str,
    pub platform_release: &'a str,
    pub platform_system: &'a str,
    pub platform_version: &'a str,
    pub python_full_version: &'a str,
    pub python_version: &'a str,
    pub sys_platform: &'a str,
}

impl<'a> TryFrom<MarkerEnvironmentBuilder<'a>> for MarkerEnvironment {
    type Error = VersionParseError;

    fn try_from(builder: MarkerEnvironmentBuilder<'a>) -> Result<Self, Self::Error> {
        Ok(MarkerEnvironment {
            inner: Arc::new(MarkerEnvironmentInner {
                implementation_name: builder.implementation_name.to_string(),
                implementation_version: builder.implementation_version.parse()?,
                os_name: builder.os_name.to_string(),
                platform_machine: builder.platform_machine.to_string(),
                platform_python_implementation: builder.platform_python_implementation.to_string(),
                platform_release: builder.platform_release.to_string(),
                platform_system: builder.platform_system.to_string(),
                platform_version: builder.platform_version.to_string(),
                python_full_version: builder.python_full_version.parse()?,
                python_version: builder.python_version.parse()?,
                sys_platform: builder.sys_platform.to_string(),
            }),
        })
    }
}
