use anyhow::Result;
use schemars::JsonSchema;
use serde::Serialize;
use tower_lsp::lsp_types::{Diagnostic, DiagnosticSeverity};

use crate::{
    SourceRange,
    errors::Suggestion,
    lsp::IntoDiagnostic,
    parsing::ast::types::{Node as AstNode, Program},
    walk::Node,
};

/// Check the provided AST for any found rule violations.
///
/// The Rule trait is automatically implemented for a few other types,
/// but it can also be manually implemented as required.
pub trait Rule<'a> {
    /// Check the AST at this specific node for any Finding(s).
    fn check(&self, node: Node<'a>, prog: &AstNode<Program>) -> Result<Vec<Discovered>>;
}

impl<'a, FnT> Rule<'a> for FnT
where
    FnT: Fn(Node<'a>, &AstNode<Program>) -> Result<Vec<Discovered>>,
{
    fn check(&self, n: Node<'a>, prog: &AstNode<Program>) -> Result<Vec<Discovered>> {
        self(n, prog)
    }
}

/// Specific discovered lint rule Violation of a particular Finding.
#[derive(Clone, Debug, ts_rs::TS, Serialize, JsonSchema)]
#[ts(export)]
#[cfg_attr(feature = "pyo3", pyo3::pyclass)]
#[serde(rename_all = "camelCase")]
pub struct Discovered {
    /// Zoo Lint Finding information.
    pub finding: Finding,

    /// Further information about the specific finding.
    pub description: String,

    /// Source code location.
    pub pos: SourceRange,

    /// Is this discovered issue overridden by the programmer?
    pub overridden: bool,

    /// Suggestion to fix the issue.
    pub suggestion: Option<Suggestion>,
}

impl Discovered {
    #[cfg(test)]
    pub fn apply_suggestion(&self, src: &str) -> Option<String> {
        let suggestion = self.suggestion.as_ref()?;
        Some(format!(
            "{}{}{}",
            &src[0..suggestion.source_range.start()],
            suggestion.insert,
            &src[suggestion.source_range.end()..]
        ))
    }
}

#[cfg(feature = "pyo3")]
#[pyo3::pymethods]
impl Discovered {
    #[getter]
    pub fn finding(&self) -> Finding {
        self.finding.clone()
    }

    #[getter]
    pub fn description(&self) -> String {
        self.description.clone()
    }

    #[getter]
    pub fn pos(&self) -> (usize, usize) {
        (self.pos.start(), self.pos.end())
    }

    #[getter]
    pub fn overridden(&self) -> bool {
        self.overridden
    }
}

impl IntoDiagnostic for Discovered {
    fn to_lsp_diagnostics(&self, code: &str) -> Vec<Diagnostic> {
        (&self).to_lsp_diagnostics(code)
    }

    fn severity(&self) -> DiagnosticSeverity {
        (&self).severity()
    }
}

impl IntoDiagnostic for &Discovered {
    fn to_lsp_diagnostics(&self, code: &str) -> Vec<Diagnostic> {
        let message = self.finding.title.to_owned();
        let source_range = self.pos;
        let edit = self.suggestion.as_ref().map(|s| s.to_lsp_edit(code));

        vec![Diagnostic {
            range: source_range.to_lsp_range(code),
            severity: Some(self.severity()),
            code: None,
            // TODO: this is neat we can pass a URL to a help page here for this specific error.
            code_description: None,
            source: Some("lint".to_string()),
            message,
            related_information: None,
            tags: None,
            data: edit.map(|e| serde_json::to_value(e).unwrap()),
        }]
    }

    fn severity(&self) -> DiagnosticSeverity {
        DiagnosticSeverity::INFORMATION
    }
}

/// Abstract lint problem type.
#[derive(Clone, Debug, PartialEq, ts_rs::TS, Serialize, JsonSchema)]
#[ts(export)]
#[cfg_attr(feature = "pyo3", pyo3::pyclass)]
#[serde(rename_all = "camelCase")]
pub struct Finding {
    /// Unique identifier for this particular issue.
    pub code: &'static str,

    /// Short one-line description of this issue.
    pub title: &'static str,

    /// Long human-readable description of this issue.
    pub description: &'static str,

    /// Is this discovered issue experimental?
    pub experimental: bool,
}

impl Finding {
    /// Create a new Discovered finding at the specific Position.
    pub fn at(&self, description: String, pos: SourceRange, suggestion: Option<Suggestion>) -> Discovered {
        Discovered {
            description,
            finding: self.clone(),
            pos,
            overridden: false,
            suggestion,
        }
    }
}

#[cfg(feature = "pyo3")]
#[pyo3::pymethods]
impl Finding {
    #[getter]
    pub fn code(&self) -> &'static str {
        self.code
    }

    #[getter]
    pub fn title(&self) -> &'static str {
        self.title
    }

    #[getter]
    pub fn description(&self) -> &'static str {
        self.description
    }

    #[getter]
    pub fn experimental(&self) -> bool {
        self.experimental
    }
}

macro_rules! def_finding {
    ( $code:ident, $title:expr_2021, $description:expr_2021 ) => {
        /// Generated Finding
        pub const $code: Finding = $crate::lint::rule::finding!($code, $title, $description);
    };
}
pub(crate) use def_finding;

macro_rules! finding {
    ( $code:ident, $title:expr_2021, $description:expr_2021 ) => {
        $crate::lint::rule::Finding {
            code: stringify!($code),
            title: $title,
            description: $description,
            experimental: false,
        }
    };
}
pub(crate) use finding;
#[cfg(test)]
pub(crate) use test::{assert_finding, assert_no_finding, test_finding, test_no_finding};

#[cfg(test)]
mod test {

    macro_rules! assert_no_finding {
        ( $check:expr_2021, $finding:expr_2021, $kcl:expr_2021 ) => {
            let prog = $crate::Program::parse_no_errs($kcl).unwrap();

            // Ensure the code still works.
            $crate::execution::parse_execute($kcl).await.unwrap();

            for discovered_finding in prog.lint($check).unwrap() {
                if discovered_finding.finding == $finding {
                    assert!(false, "Finding {:?} was emitted", $finding.code);
                }
            }
        };
    }

    macro_rules! assert_finding {
        ( $check:expr_2021, $finding:expr_2021, $kcl:expr_2021, $output:expr_2021, $suggestion:expr_2021 ) => {
            let prog = $crate::Program::parse_no_errs($kcl).unwrap();

            // Ensure the code still works.
            $crate::execution::parse_execute($kcl).await.unwrap();

            for discovered_finding in prog.lint($check).unwrap() {
                pretty_assertions::assert_eq!(discovered_finding.description, $output,);

                if discovered_finding.finding == $finding {
                    pretty_assertions::assert_eq!(
                        discovered_finding.suggestion.clone().map(|s| s.insert),
                        $suggestion,
                    );

                    if discovered_finding.suggestion.is_some() {
                        // Apply the suggestion to the source code.
                        let code = discovered_finding.apply_suggestion($kcl).unwrap();

                        // Ensure the code still works.
                        $crate::execution::parse_execute(&code).await.unwrap();
                    }
                    return;
                }
            }
            assert!(false, "Finding {:?} was not emitted", $finding.code);
        };
    }

    macro_rules! test_finding {
        ( $name:ident, $check:expr_2021, $finding:expr_2021, $kcl:expr_2021, $output:expr_2021, $suggestion:expr_2021 ) => {
            #[tokio::test]
            async fn $name() {
                $crate::lint::rule::assert_finding!($check, $finding, $kcl, $output, $suggestion);
            }
        };
    }

    macro_rules! test_no_finding {
        ( $name:ident, $check:expr_2021, $finding:expr_2021, $kcl:expr_2021 ) => {
            #[tokio::test]
            async fn $name() {
                $crate::lint::rule::assert_no_finding!($check, $finding, $kcl);
            }
        };
    }

    pub(crate) use assert_finding;
    pub(crate) use assert_no_finding;
    pub(crate) use test_finding;
    pub(crate) use test_no_finding;
}