//! Semantic Tokens helpers

use std::ops;

use lsp_types::{Range, SemanticToken, SemanticTokenModifier, SemanticTokenType, SemanticTokens};

macro_rules! define_semantic_token_types {
    ($(($ident:ident, $string:literal)),*$(,)?) => {
        $(pub(crate) const $ident: SemanticTokenType = SemanticTokenType::new($string);)*

        pub(crate) const SUPPORTED_TYPES: &[SemanticTokenType] = &[
            SemanticTokenType::COMMENT,
            SemanticTokenType::KEYWORD,
            SemanticTokenType::STRING,
            SemanticTokenType::NUMBER,
            SemanticTokenType::REGEXP,
            SemanticTokenType::OPERATOR,
            SemanticTokenType::NAMESPACE,
            SemanticTokenType::TYPE,
            SemanticTokenType::STRUCT,
            SemanticTokenType::CLASS,
            SemanticTokenType::INTERFACE,
            SemanticTokenType::ENUM,
            SemanticTokenType::TYPE_PARAMETER,
            SemanticTokenType::FUNCTION,
            SemanticTokenType::MEMBER,
            SemanticTokenType::PROPERTY,
            SemanticTokenType::MACRO,
            SemanticTokenType::VARIABLE,
            SemanticTokenType::PARAMETER,
            SemanticTokenType::LABEL,
            $($ident),*
        ];
    };
}

define_semantic_token_types![
    (ATTRIBUTE, "attribute"),
    (BUILTIN_TYPE, "builtinType"),
    (ENUM_MEMBER, "enumMember"),
    (LIFETIME, "lifetime"),
    (TYPE_ALIAS, "typeAlias"),
    (UNION, "union"),
    (UNRESOLVED_REFERENCE, "unresolvedReference"),
    (FORMAT_SPECIFIER, "formatSpecifier"),
];

macro_rules! define_semantic_token_modifiers {
    ($(($ident:ident, $string:literal)),*$(,)?) => {
        $(pub(crate) const $ident: SemanticTokenModifier = SemanticTokenModifier::new($string);)*

        pub(crate) const SUPPORTED_MODIFIERS: &[SemanticTokenModifier] = &[
            SemanticTokenModifier::DOCUMENTATION,
            SemanticTokenModifier::DECLARATION,
            SemanticTokenModifier::DEFINITION,
            SemanticTokenModifier::STATIC,
            SemanticTokenModifier::ABSTRACT,
            SemanticTokenModifier::DEPRECATED,
            SemanticTokenModifier::READONLY,
            $($ident),*
        ];
    };
}

define_semantic_token_modifiers![
    (CONSTANT, "constant"),
    (CONTROL_FLOW, "controlFlow"),
    (MUTABLE, "mutable"),
    (UNSAFE, "unsafe"),
];

#[derive(Default)]
pub(crate) struct ModifierSet(pub(crate) u32);

impl ops::BitOrAssign<SemanticTokenModifier> for ModifierSet {
    fn bitor_assign(&mut self, rhs: SemanticTokenModifier) {
        let idx = SUPPORTED_MODIFIERS.iter().position(|it| it == &rhs).unwrap();
        self.0 |= 1 << idx;
    }
}

/// Tokens are encoded relative to each other.
///
/// This is a direct port of https://github.com/microsoft/vscode-languageserver-node/blob/f425af9de46a0187adb78ec8a46b9b2ce80c5412/server/src/sematicTokens.proposed.ts#L45
#[derive(Default)]
pub(crate) struct SemanticTokensBuilder {
    prev_line: u32,
    prev_char: u32,
    data: Vec<SemanticToken>,
}

impl SemanticTokensBuilder {
    /// Push a new token onto the builder
    pub fn push(&mut self, range: Range, token_index: u32, modifier_bitset: u32) {
        let mut push_line = range.start.line as u32;
        let mut push_char = range.start.character as u32;

        if !self.data.is_empty() {
            push_line -= self.prev_line;
            if push_line == 0 {
                push_char -= self.prev_char;
            }
        }

        // A token cannot be multiline
        let token_len = range.end.character - range.start.character;

        let token = SemanticToken {
            delta_line: push_line,
            delta_start: push_char,
            length: token_len as u32,
            token_type: token_index,
            token_modifiers_bitset: modifier_bitset,
        };

        self.data.push(token);

        self.prev_line = range.start.line as u32;
        self.prev_char = range.start.character as u32;
    }

    pub fn build(self) -> SemanticTokens {
        SemanticTokens { result_id: None, data: self.data }
    }
}

pub fn type_index(type_: SemanticTokenType) -> u32 {
    SUPPORTED_TYPES.iter().position(|it| *it == type_).unwrap() as u32
}