use hir::{db::AstDatabase, InFile};
use ide_assists::Assist;
use ide_db::base_db::FilePosition;
use syntax::AstNode;

use crate::{
    diagnostics::{unresolved_fix, Diagnostic, DiagnosticsContext},
    references::rename::rename_with_semantics,
    Severity,
};

// Diagnostic: incorrect-ident-case
//
// This diagnostic is triggered if an item name doesn't follow https://doc.rust-lang.org/1.0.0/style/style/naming/README.html[Rust naming convention].
pub(super) fn incorrect_case(ctx: &DiagnosticsContext<'_>, d: &hir::IncorrectCase) -> Diagnostic {
    Diagnostic::new(
        "incorrect-ident-case",
        format!(
            "{} `{}` should have {} name, e.g. `{}`",
            d.ident_type, d.ident_text, d.expected_case, d.suggested_text
        ),
        ctx.sema.diagnostics_display_range(InFile::new(d.file, d.ident.clone().into())).range,
    )
    .severity(Severity::WeakWarning)
    .with_fixes(fixes(ctx, d))
}

fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::IncorrectCase) -> Option<Vec<Assist>> {
    let root = ctx.sema.db.parse_or_expand(d.file)?;
    let name_node = d.ident.to_node(&root);

    let name_node = InFile::new(d.file, name_node.syntax());
    let frange = name_node.original_file_range(ctx.sema.db);
    let file_position = FilePosition { file_id: frange.file_id, offset: frange.range.start() };

    let label = format!("Rename to {}", d.suggested_text);
    let mut res = unresolved_fix("change_case", &label, frange.range);
    if ctx.resolve.should_resolve(&res.id) {
        let source_change = rename_with_semantics(&ctx.sema, file_position, &d.suggested_text);
        res.source_change = Some(source_change.ok().unwrap_or_default());
    }

    Some(vec![res])
}

#[cfg(test)]
mod change_case {
    use crate::{
        diagnostics::tests::{check_diagnostics, check_fix},
        fixture, AssistResolveStrategy, DiagnosticsConfig,
    };

    #[test]
    fn test_rename_incorrect_case() {
        check_fix(
            r#"
pub struct test_struct$0 { one: i32 }

pub fn some_fn(val: test_struct) -> test_struct {
    test_struct { one: val.one + 1 }
}
"#,
            r#"
pub struct TestStruct { one: i32 }

pub fn some_fn(val: TestStruct) -> TestStruct {
    TestStruct { one: val.one + 1 }
}
"#,
        );

        check_fix(
            r#"
pub fn some_fn(NonSnakeCase$0: u8) -> u8 {
    NonSnakeCase
}
"#,
            r#"
pub fn some_fn(non_snake_case: u8) -> u8 {
    non_snake_case
}
"#,
        );

        check_fix(
            r#"
pub fn SomeFn$0(val: u8) -> u8 {
    if val != 0 { SomeFn(val - 1) } else { val }
}
"#,
            r#"
pub fn some_fn(val: u8) -> u8 {
    if val != 0 { some_fn(val - 1) } else { val }
}
"#,
        );

        check_fix(
            r#"
fn some_fn() {
    let whatAWeird_Formatting$0 = 10;
    another_func(whatAWeird_Formatting);
}
"#,
            r#"
fn some_fn() {
    let what_a_weird_formatting = 10;
    another_func(what_a_weird_formatting);
}
"#,
        );
    }

    #[test]
    fn test_uppercase_const_no_diagnostics() {
        check_diagnostics(
            r#"
fn foo() {
    const ANOTHER_ITEM$0: &str = "some_item";
}
"#,
        );
    }

    #[test]
    fn test_rename_incorrect_case_struct_method() {
        check_fix(
            r#"
pub struct TestStruct;

impl TestStruct {
    pub fn SomeFn$0() -> TestStruct {
        TestStruct
    }
}
"#,
            r#"
pub struct TestStruct;

impl TestStruct {
    pub fn some_fn() -> TestStruct {
        TestStruct
    }
}
"#,
        );
    }

    #[test]
    fn test_single_incorrect_case_diagnostic_in_function_name_issue_6970() {
        let input = r#"fn FOO$0() {}"#;
        let expected = r#"fn foo() {}"#;

        let (analysis, file_position) = fixture::position(input);
        let diagnostics = analysis
            .diagnostics(
                &DiagnosticsConfig::default(),
                AssistResolveStrategy::All,
                file_position.file_id,
            )
            .unwrap();
        assert_eq!(diagnostics.len(), 1);

        check_fix(input, expected);
    }

    #[test]
    fn incorrect_function_name() {
        check_diagnostics(
            r#"
fn NonSnakeCaseName() {}
// ^^^^^^^^^^^^^^^^ Function `NonSnakeCaseName` should have snake_case name, e.g. `non_snake_case_name`
"#,
        );
    }

    #[test]
    fn incorrect_function_params() {
        check_diagnostics(
            r#"
fn foo(SomeParam: u8) {}
    // ^^^^^^^^^ Parameter `SomeParam` should have snake_case name, e.g. `some_param`

fn foo2(ok_param: &str, CAPS_PARAM: u8) {}
                     // ^^^^^^^^^^ Parameter `CAPS_PARAM` should have snake_case name, e.g. `caps_param`
"#,
        );
    }

    #[test]
    fn incorrect_variable_names() {
        check_diagnostics(
            r#"
fn foo() {
    let SOME_VALUE = 10;
     // ^^^^^^^^^^ Variable `SOME_VALUE` should have snake_case name, e.g. `some_value`
    let AnotherValue = 20;
     // ^^^^^^^^^^^^ Variable `AnotherValue` should have snake_case name, e.g. `another_value`
}
"#,
        );
    }

    #[test]
    fn incorrect_struct_names() {
        check_diagnostics(
            r#"
struct non_camel_case_name {}
    // ^^^^^^^^^^^^^^^^^^^ Structure `non_camel_case_name` should have CamelCase name, e.g. `NonCamelCaseName`

struct SCREAMING_CASE {}
    // ^^^^^^^^^^^^^^ Structure `SCREAMING_CASE` should have CamelCase name, e.g. `ScreamingCase`
"#,
        );
    }

    #[test]
    fn no_diagnostic_for_camel_cased_acronyms_in_struct_name() {
        check_diagnostics(
            r#"
struct AABB {}
"#,
        );
    }

    #[test]
    fn incorrect_struct_field() {
        check_diagnostics(
            r#"
struct SomeStruct { SomeField: u8 }
                 // ^^^^^^^^^ Field `SomeField` should have snake_case name, e.g. `some_field`
"#,
        );
    }

    #[test]
    fn incorrect_enum_names() {
        check_diagnostics(
            r#"
enum some_enum { Val(u8) }
  // ^^^^^^^^^ Enum `some_enum` should have CamelCase name, e.g. `SomeEnum`

enum SOME_ENUM {}
  // ^^^^^^^^^ Enum `SOME_ENUM` should have CamelCase name, e.g. `SomeEnum`
"#,
        );
    }

    #[test]
    fn no_diagnostic_for_camel_cased_acronyms_in_enum_name() {
        check_diagnostics(
            r#"
enum AABB {}
"#,
        );
    }

    #[test]
    fn incorrect_enum_variant_name() {
        check_diagnostics(
            r#"
enum SomeEnum { SOME_VARIANT(u8) }
             // ^^^^^^^^^^^^ Variant `SOME_VARIANT` should have CamelCase name, e.g. `SomeVariant`
"#,
        );
    }

    #[test]
    fn incorrect_const_name() {
        check_diagnostics(
            r#"
const some_weird_const: u8 = 10;
   // ^^^^^^^^^^^^^^^^ Constant `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
"#,
        );
    }

    #[test]
    fn incorrect_static_name() {
        check_diagnostics(
            r#"
static some_weird_const: u8 = 10;
    // ^^^^^^^^^^^^^^^^ Static variable `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
"#,
        );
    }

    #[test]
    fn fn_inside_impl_struct() {
        check_diagnostics(
            r#"
struct someStruct;
    // ^^^^^^^^^^ Structure `someStruct` should have CamelCase name, e.g. `SomeStruct`

impl someStruct {
    fn SomeFunc(&self) {
    // ^^^^^^^^ Function `SomeFunc` should have snake_case name, e.g. `some_func`
        let WHY_VAR_IS_CAPS = 10;
         // ^^^^^^^^^^^^^^^ Variable `WHY_VAR_IS_CAPS` should have snake_case name, e.g. `why_var_is_caps`
    }
}
"#,
        );
    }

    #[test]
    fn no_diagnostic_for_enum_varinats() {
        check_diagnostics(
            r#"
enum Option { Some, None }

fn main() {
    match Option::None {
        None => (),
        Some => (),
    }
}
"#,
        );
    }

    #[test]
    fn non_let_bind() {
        check_diagnostics(
            r#"
enum Option { Some, None }

fn main() {
    match Option::None {
        SOME_VAR @ None => (),
     // ^^^^^^^^ Variable `SOME_VAR` should have snake_case name, e.g. `some_var`
        Some => (),
    }
}
"#,
        );
    }

    #[test]
    fn allow_attributes_crate_attr() {
        check_diagnostics(
            r#"
#![allow(non_snake_case)]

mod F {
    fn CheckItWorksWithCrateAttr(BAD_NAME_HI: u8) {}
}
    "#,
        );
    }

    #[test]
    #[ignore]
    fn bug_trait_inside_fn() {
        // FIXME:
        // This is broken, and in fact, should not even be looked at by this
        // lint in the first place. There's weird stuff going on in the
        // collection phase.
        // It's currently being brought in by:
        // * validate_func on `a` recursing into modules
        // * then it finds the trait and then the function while iterating
        //   through modules
        // * then validate_func is called on Dirty
        // * ... which then proceeds to look at some unknown module taking no
        //   attrs from either the impl or the fn a, and then finally to the root
        //   module
        //
        // It should find the attribute on the trait, but it *doesn't even see
        // the trait* as far as I can tell.

        check_diagnostics(
            r#"
trait T { fn a(); }
struct U {}
impl T for U {
    fn a() {
        // this comes out of bitflags, mostly
        #[allow(non_snake_case)]
        trait __BitFlags {
            const HiImAlsoBad: u8 = 2;
            #[inline]
            fn Dirty(&self) -> bool {
                false
            }
        }

    }
}
    "#,
        );
    }

    #[test]
    fn infinite_loop_inner_items() {
        check_diagnostics(
            r#"
fn qualify() {
    mod foo {
        use super::*;
    }
}
            "#,
        )
    }

    #[test] // Issue #8809.
    fn parenthesized_parameter() {
        check_diagnostics(r#"fn f((O): _) {}"#)
    }

    #[test]
    fn ignores_extern_items() {
        cov_mark::check!(extern_func_incorrect_case_ignored);
        cov_mark::check!(extern_static_incorrect_case_ignored);
        check_diagnostics(
            r#"
extern {
    fn NonSnakeCaseName(SOME_VAR: u8) -> u8;
    pub static SomeStatic: u8 = 10;
}
            "#,
        );
    }

    #[test]
    #[ignore]
    fn bug_traits_arent_checked() {
        // FIXME: Traits and functions in traits aren't currently checked by
        // r-a, even though rustc will complain about them.
        check_diagnostics(
            r#"
trait BAD_TRAIT {
    // ^^^^^^^^^ Trait `BAD_TRAIT` should have CamelCase name, e.g. `BadTrait`
    fn BAD_FUNCTION();
    // ^^^^^^^^^^^^ Function `BAD_FUNCTION` should have snake_case name, e.g. `bad_function`
    fn BadFunction();
    // ^^^^^^^^^^^^ Function `BadFunction` should have snake_case name, e.g. `bad_function`
}
    "#,
        );
    }

    #[test]
    fn allow_attributes() {
        check_diagnostics(
            r#"
#[allow(non_snake_case)]
fn NonSnakeCaseName(SOME_VAR: u8) -> u8{
    // cov_flags generated output from elsewhere in this file
    extern "C" {
        #[no_mangle]
        static lower_case: u8;
    }

    let OtherVar = SOME_VAR + 1;
    OtherVar
}

#[allow(nonstandard_style)]
mod CheckNonstandardStyle {
    fn HiImABadFnName() {}
}

#[allow(bad_style)]
mod CheckBadStyle {
    fn HiImABadFnName() {}
}

mod F {
    #![allow(non_snake_case)]
    fn CheckItWorksWithModAttr(BAD_NAME_HI: u8) {}
}

#[allow(non_snake_case, non_camel_case_types)]
pub struct some_type {
    SOME_FIELD: u8,
    SomeField: u16,
}

#[allow(non_upper_case_globals)]
pub const some_const: u8 = 10;

#[allow(non_upper_case_globals)]
pub static SomeStatic: u8 = 10;
    "#,
        );
    }
}