/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */

//! Sections within an AWS config profile.

use crate::env_config::normalize;
use crate::env_config::parse::{parse_profile_file, EnvConfigParseError};
use crate::env_config::property::{Properties, Property};
use crate::env_config::source::Source;
use std::borrow::Cow;
use std::collections::HashMap;

/// Represents a top-level section (e.g., `[profile name]`) in a config file.
pub(crate) trait Section {
    /// The name of this section
    fn name(&self) -> &str;

    /// Returns all the properties in this section
    #[allow(dead_code)]
    fn properties(&self) -> &HashMap<String, Property>;

    /// Returns a reference to the property named `name`
    fn get(&self, name: &str) -> Option<&str>;

    /// True if there are no properties in this section.
    #[allow(dead_code)]
    fn is_empty(&self) -> bool;

    /// Insert a property into a section
    fn insert(&mut self, name: String, value: Property);
}

#[derive(Debug, Clone, Eq, PartialEq)]
pub(super) struct SectionInner {
    pub(super) name: String,
    pub(super) properties: HashMap<String, Property>,
}

impl Section for SectionInner {
    fn name(&self) -> &str {
        &self.name
    }

    fn properties(&self) -> &HashMap<String, Property> {
        &self.properties
    }

    fn get(&self, name: &str) -> Option<&str> {
        self.properties
            .get(name.to_ascii_lowercase().as_str())
            .map(|prop| prop.value())
    }

    fn is_empty(&self) -> bool {
        self.properties.is_empty()
    }

    fn insert(&mut self, name: String, value: Property) {
        self.properties.insert(name.to_ascii_lowercase(), value);
    }
}

/// An individual configuration profile
///
/// An AWS config may be composed of a multiple named profiles within a [`EnvConfigSections`].
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct Profile(SectionInner);

impl Profile {
    /// Create a new profile
    pub fn new(name: impl Into<String>, properties: HashMap<String, Property>) -> Self {
        Self(SectionInner {
            name: name.into(),
            properties,
        })
    }

    /// The name of this profile
    pub fn name(&self) -> &str {
        self.0.name()
    }

    /// Returns a reference to the property named `name`
    pub fn get(&self, name: &str) -> Option<&str> {
        self.0.get(name)
    }
}

impl Section for Profile {
    fn name(&self) -> &str {
        self.0.name()
    }

    fn properties(&self) -> &HashMap<String, Property> {
        self.0.properties()
    }

    fn get(&self, name: &str) -> Option<&str> {
        self.0.get(name)
    }

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

    fn insert(&mut self, name: String, value: Property) {
        self.0.insert(name, value)
    }
}

/// A `[sso-session name]` section in the config.
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct SsoSession(SectionInner);

impl SsoSession {
    /// Create a new SSO session section.
    pub(super) fn new(name: impl Into<String>, properties: HashMap<String, Property>) -> Self {
        Self(SectionInner {
            name: name.into(),
            properties,
        })
    }

    /// Returns a reference to the property named `name`
    pub fn get(&self, name: &str) -> Option<&str> {
        self.0.get(name)
    }
}

impl Section for SsoSession {
    fn name(&self) -> &str {
        self.0.name()
    }

    fn properties(&self) -> &HashMap<String, Property> {
        self.0.properties()
    }

    fn get(&self, name: &str) -> Option<&str> {
        self.0.get(name)
    }

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

    fn insert(&mut self, name: String, value: Property) {
        self.0.insert(name, value)
    }
}

/// A top-level configuration source containing multiple named profiles
#[derive(Debug, Eq, Clone, PartialEq)]
pub struct EnvConfigSections {
    pub(crate) profiles: HashMap<String, Profile>,
    pub(crate) selected_profile: Cow<'static, str>,
    pub(crate) sso_sessions: HashMap<String, SsoSession>,
    pub(crate) other_sections: Properties,
}

impl Default for EnvConfigSections {
    fn default() -> Self {
        Self {
            profiles: Default::default(),
            selected_profile: "default".into(),
            sso_sessions: Default::default(),
            other_sections: Default::default(),
        }
    }
}

impl EnvConfigSections {
    /// Create a new Profile set directly from a HashMap
    ///
    /// This method creates a ProfileSet directly from a hashmap with no normalization for test purposes.
    #[cfg(test)]
    pub fn new(
        profiles: HashMap<String, HashMap<String, String>>,
        selected_profile: impl Into<Cow<'static, str>>,
        sso_sessions: HashMap<String, HashMap<String, String>>,
        other_sections: Properties,
    ) -> Self {
        let mut base = EnvConfigSections {
            selected_profile: selected_profile.into(),
            ..Default::default()
        };
        for (name, profile) in profiles {
            base.profiles.insert(
                name.clone(),
                Profile::new(
                    name,
                    profile
                        .into_iter()
                        .map(|(k, v)| (k.clone(), Property::new(k, v)))
                        .collect(),
                ),
            );
        }
        for (name, session) in sso_sessions {
            base.sso_sessions.insert(
                name.clone(),
                SsoSession::new(
                    name,
                    session
                        .into_iter()
                        .map(|(k, v)| (k.clone(), Property::new(k, v)))
                        .collect(),
                ),
            );
        }
        base.other_sections = other_sections;
        base
    }

    /// Retrieves a key-value pair from the currently selected profile
    pub fn get(&self, key: &str) -> Option<&str> {
        self.profiles
            .get(self.selected_profile.as_ref())
            .and_then(|profile| profile.get(key))
    }

    /// Retrieves a named profile from the profile set
    pub fn get_profile(&self, profile_name: &str) -> Option<&Profile> {
        self.profiles.get(profile_name)
    }

    /// Returns the name of the currently selected profile
    pub fn selected_profile(&self) -> &str {
        self.selected_profile.as_ref()
    }

    /// Returns true if no profiles are contained in this profile set
    pub fn is_empty(&self) -> bool {
        self.profiles.is_empty()
    }

    /// Returns the names of the profiles in this config
    pub fn profiles(&self) -> impl Iterator<Item = &str> {
        self.profiles.keys().map(String::as_ref)
    }

    /// Returns the names of the SSO sessions in this config
    pub fn sso_sessions(&self) -> impl Iterator<Item = &str> {
        self.sso_sessions.keys().map(String::as_ref)
    }

    /// Retrieves a named SSO session from the config
    pub fn sso_session(&self, name: &str) -> Option<&SsoSession> {
        self.sso_sessions.get(name)
    }

    /// Returns a struct allowing access to other sections in the profile config
    pub fn other_sections(&self) -> &Properties {
        &self.other_sections
    }

    /// Given a [`Source`] of profile config, parse and merge them into a `EnvConfigSections`.
    pub fn parse(source: Source) -> Result<Self, EnvConfigParseError> {
        let mut base = EnvConfigSections {
            selected_profile: source.profile,
            ..Default::default()
        };

        for file in source.files {
            normalize::merge_in(&mut base, parse_profile_file(&file)?, file.kind);
        }
        Ok(base)
    }
}

#[cfg(test)]
mod test {
    use super::EnvConfigSections;
    use crate::env_config::file::EnvConfigFileKind;
    use crate::env_config::section::Section;
    use crate::env_config::source::{File, Source};
    use arbitrary::{Arbitrary, Unstructured};
    use serde::Deserialize;
    use std::collections::HashMap;
    use std::error::Error;
    use std::fs;
    use tracing_test::traced_test;

    /// Run all tests from `test-data/profile-parser-tests.json`
    ///
    /// These represent the bulk of the test cases and reach 100% coverage of the parser.
    #[test]
    #[traced_test]
    fn run_tests() -> Result<(), Box<dyn Error>> {
        let tests = fs::read_to_string("test-data/profile-parser-tests.json")?;
        let tests: ParserTests = serde_json::from_str(&tests)?;
        for (i, test) in tests.tests.into_iter().enumerate() {
            eprintln!("test: {}", i);
            check(test);
        }
        Ok(())
    }

    #[test]
    fn empty_source_empty_profile() {
        let source = make_source(ParserInput {
            config_file: Some("".to_string()),
            credentials_file: Some("".to_string()),
        });

        let profile_set = EnvConfigSections::parse(source).expect("empty profiles are valid");
        assert!(profile_set.is_empty());
    }

    #[test]
    fn profile_names_are_exposed() {
        let source = make_source(ParserInput {
            config_file: Some("[profile foo]\n[profile bar]".to_string()),
            credentials_file: Some("".to_string()),
        });

        let profile_set = EnvConfigSections::parse(source).expect("profiles loaded");

        let mut profile_names: Vec<_> = profile_set.profiles().collect();
        profile_names.sort();
        assert_eq!(profile_names, vec!["bar", "foo"]);
    }

    /// Run all tests from the fuzzing corpus to validate coverage
    #[test]
    #[ignore]
    fn run_fuzz_tests() -> Result<(), Box<dyn Error>> {
        let fuzz_corpus = fs::read_dir("fuzz/corpus/profile-parser")?
            .map(|res| res.map(|entry| entry.path()))
            .collect::<Result<Vec<_>, _>>()?;
        for file in fuzz_corpus {
            let raw = fs::read(file)?;
            let mut unstructured = Unstructured::new(&raw);
            let (conf, creds): (Option<&str>, Option<&str>) =
                Arbitrary::arbitrary(&mut unstructured)?;
            let profile_source = Source {
                files: vec![
                    File {
                        kind: EnvConfigFileKind::Config,
                        path: Some("~/.aws/config".to_string()),
                        contents: conf.unwrap_or_default().to_string(),
                    },
                    File {
                        kind: EnvConfigFileKind::Credentials,
                        path: Some("~/.aws/credentials".to_string()),
                        contents: creds.unwrap_or_default().to_string(),
                    },
                ],
                profile: "default".into(),
            };
            // don't care if parse fails, just don't panic
            let _ = EnvConfigSections::parse(profile_source);
        }

        Ok(())
    }

    // for test comparison purposes, flatten a profile into a hashmap
    #[derive(Debug)]
    struct FlattenedProfileSet {
        profiles: HashMap<String, HashMap<String, String>>,
        sso_sessions: HashMap<String, HashMap<String, String>>,
    }
    fn flatten(config: EnvConfigSections) -> FlattenedProfileSet {
        FlattenedProfileSet {
            profiles: flatten_sections(config.profiles.values().map(|p| p as _)),
            sso_sessions: flatten_sections(config.sso_sessions.values().map(|s| s as _)),
        }
    }
    fn flatten_sections<'a>(
        sections: impl Iterator<Item = &'a dyn Section>,
    ) -> HashMap<String, HashMap<String, String>> {
        sections
            .map(|section| {
                (
                    section.name().to_string(),
                    section
                        .properties()
                        .values()
                        .map(|prop| (prop.key().to_owned(), prop.value().to_owned()))
                        .collect(),
                )
            })
            .collect()
    }

    fn make_source(input: ParserInput) -> Source {
        Source {
            files: vec![
                File {
                    kind: EnvConfigFileKind::Config,
                    path: Some("~/.aws/config".to_string()),
                    contents: input.config_file.unwrap_or_default(),
                },
                File {
                    kind: EnvConfigFileKind::Credentials,
                    path: Some("~/.aws/credentials".to_string()),
                    contents: input.credentials_file.unwrap_or_default(),
                },
            ],
            profile: "default".into(),
        }
    }

    // wrapper to generate nicer errors during test failure
    fn check(test_case: ParserTest) {
        let copy = test_case.clone();
        let parsed = EnvConfigSections::parse(make_source(test_case.input));
        let res = match (parsed.map(flatten), &test_case.output) {
            (
                Ok(FlattenedProfileSet {
                    profiles: actual_profiles,
                    sso_sessions: actual_sso_sessions,
                }),
                ParserOutput::Config {
                    profiles,
                    sso_sessions,
                },
            ) => {
                if profiles != &actual_profiles {
                    Err(format!(
                        "mismatched profiles:\nExpected: {profiles:#?}\nActual: {actual_profiles:#?}",
                    ))
                } else if sso_sessions != &actual_sso_sessions {
                    Err(format!(
                        "mismatched sso_sessions:\nExpected: {sso_sessions:#?}\nActual: {actual_sso_sessions:#?}",
                    ))
                } else {
                    Ok(())
                }
            }
            (Err(msg), ParserOutput::ErrorContaining(substr)) => {
                if format!("{}", msg).contains(substr) {
                    Ok(())
                } else {
                    Err(format!("Expected {} to contain {}", msg, substr))
                }
            }
            (Ok(output), ParserOutput::ErrorContaining(err)) => Err(format!(
                "expected an error: {err} but parse succeeded:\n{output:#?}",
            )),
            (Err(err), ParserOutput::Config { .. }) => {
                Err(format!("Expected to succeed but got: {}", err))
            }
        };
        if let Err(e) = res {
            eprintln!("Test case failed: {:#?}", copy);
            eprintln!("failure: {}", e);
            panic!("test failed")
        }
    }

    #[derive(Deserialize, Debug)]
    #[serde(rename_all = "camelCase")]
    struct ParserTests {
        tests: Vec<ParserTest>,
    }

    #[derive(Deserialize, Debug, Clone)]
    #[serde(rename_all = "camelCase")]
    struct ParserTest {
        _name: String,
        input: ParserInput,
        output: ParserOutput,
    }

    #[derive(Deserialize, Debug, Clone)]
    #[serde(rename_all = "camelCase")]
    enum ParserOutput {
        Config {
            profiles: HashMap<String, HashMap<String, String>>,
            #[serde(default)]
            sso_sessions: HashMap<String, HashMap<String, String>>,
        },
        ErrorContaining(String),
    }

    #[derive(Deserialize, Debug, Clone)]
    #[serde(rename_all = "camelCase")]
    struct ParserInput {
        config_file: Option<String>,
        credentials_file: Option<String>,
    }
}