use rustc_hash::FxHashMap;

use oxc_ast::{Comment, CommentKind};
use oxc_syntax::identifier::is_line_terminator;

use crate::{Codegen, LegalComment};

pub(crate) type CommentsMap = FxHashMap</* attached_to */ u32, Vec<Comment>>;

impl Codegen<'_> {
    pub(crate) fn build_comments(&mut self, comments: &[Comment]) {
        for comment in comments {
            self.comments.entry(comment.attached_to).or_default().push(*comment);
        }
    }

    pub(crate) fn has_comment(&self, start: u32) -> bool {
        self.comments.contains_key(&start)
    }

    pub(crate) fn has_annotation_comment(&self, start: u32) -> bool {
        if !self.options.print_annotation_comments() {
            return false;
        }
        self.comments.get(&start).is_some_and(|comments| {
            comments.iter().any(|comment| self.is_annotation_comment(comment))
        })
    }

    pub(crate) fn has_non_annotation_comment(&self, start: u32) -> bool {
        if self.options.print_annotation_comments() {
            self.comments.get(&start).is_some_and(|comments| {
                comments.iter().any(|comment| !self.is_annotation_comment(comment))
            })
        } else {
            self.has_comment(start)
        }
    }

    /// `#__PURE__` Notation Specification
    ///
    /// <https://github.com/javascript-compiler-hints/compiler-notations-spec/blob/c14f7e197cb225c9eee877143536665ce3150712/pure-notation-spec.md>
    fn is_annotation_comment(&self, comment: &Comment) -> bool {
        let s = comment.content_span().source_text(self.source_text).trim_start();
        if let Some(s) = s.strip_prefix(['@', '#']) {
            s.starts_with("__PURE__") || s.starts_with("__NO_SIDE_EFFECTS__")
        } else {
            false
        }
    }

    /// Whether to keep leading comments.
    fn is_leading_comments(&self, comment: &Comment) -> bool {
        comment.preceded_by_newline
            && (comment.is_jsdoc(self.source_text)
                || (comment.is_line() && self.is_annotation_comment(comment)))
            && !comment.content_span().source_text(self.source_text).chars().all(|c| c == '*')
        // webpack comment `/*****/`
    }

    pub(crate) fn print_leading_comments(&mut self, start: u32) {
        if self.options.minify {
            return;
        }
        let Some(comments) = self.comments.remove(&start) else {
            return;
        };
        let (comments, unused_comments): (Vec<_>, Vec<_>) =
            comments.into_iter().partition(|comment| self.is_leading_comments(comment));
        self.print_comments(start, &comments, unused_comments);
    }

    pub(crate) fn get_statement_comments(
        &mut self,
        start: u32,
    ) -> Option<(Vec<Comment>, Vec<Comment>)> {
        if self.options.minify {
            return None;
        }

        let comments = self.comments.remove(&start)?;

        let mut leading_comments = vec![];
        let mut unused_comments = vec![];

        for comment in comments {
            if self.is_leading_comments(&comment) {
                leading_comments.push(comment);
                continue;
            }
            if comment.is_legal(self.source_text) {
                match &self.options.legal_comments {
                    LegalComment::None if self.options.comments => {
                        leading_comments.push(comment);
                        continue;
                    }
                    LegalComment::Inline => {
                        leading_comments.push(comment);
                        continue;
                    }
                    LegalComment::Eof | LegalComment::Linked(_) | LegalComment::External => {
                        self.legal_comments.push(comment);
                        continue;
                    }
                    LegalComment::None => {}
                }
            }
            unused_comments.push(comment);
        }

        Some((leading_comments, unused_comments))
    }

    /// A statement comment also includes legal comments
    pub(crate) fn print_statement_comments(&mut self, start: u32) {
        if let Some((comments, unused)) = self.get_statement_comments(start) {
            self.print_comments(start, &comments, unused);
        }
    }

    pub(crate) fn print_annotation_comments(&mut self, node_start: u32) {
        if !self.options.print_annotation_comments() {
            return;
        }

        // If there is has annotation comments awaiting move to here, print them.
        let start = self.start_of_annotation_comment.take().unwrap_or(node_start);

        let Some(comments) = self.comments.remove(&start) else { return };

        for comment in comments {
            if !self.is_annotation_comment(&comment) {
                continue;
            }
            if comment.is_line() {
                self.print_str("/*");
                self.print_str(comment.content_span().source_text(self.source_text));
                self.print_str("*/");
            } else {
                self.print_str(comment.span.source_text(self.source_text));
            }
            self.print_hard_space();
        }
    }

    pub(crate) fn print_expr_comments(&mut self, start: u32) -> bool {
        if self.options.minify {
            return false;
        }
        let Some(comments) = self.comments.remove(&start) else { return false };

        let (annotation_comments, comments): (Vec<_>, Vec<_>) =
            comments.into_iter().partition(|comment| self.is_annotation_comment(comment));

        if !annotation_comments.is_empty() {
            self.comments.insert(start, annotation_comments);
        }

        for comment in &comments {
            self.print_hard_newline();
            self.print_indent();
            self.print_comment(comment);
        }

        if comments.is_empty() {
            false
        } else {
            self.print_hard_newline();
            true
        }
    }

    pub(crate) fn print_comments(
        &mut self,
        start: u32,
        comments: &[Comment],
        unused_comments: Vec<Comment>,
    ) {
        for (i, comment) in comments.iter().enumerate() {
            if i == 0 {
                if comment.preceded_by_newline {
                    // Skip printing newline if this comment is already on a newline.
                    if let Some(b) = self.last_byte() {
                        match b {
                            b'\n' => self.print_indent(),
                            b'\t' => { /* noop */ }
                            _ => {
                                self.print_hard_newline();
                                self.print_indent();
                            }
                        }
                    }
                } else {
                    self.print_indent();
                }
            }
            if i >= 1 {
                if comment.preceded_by_newline {
                    self.print_hard_newline();
                    self.print_indent();
                } else if comment.is_legal(self.source_text) {
                    self.print_hard_newline();
                }
            }
            self.print_comment(comment);
            if i == comments.len() - 1 {
                if comment.is_line() || comment.followed_by_newline {
                    self.print_hard_newline();
                } else {
                    self.print_next_indent_as_space = true;
                }
            }
        }

        if !unused_comments.is_empty() {
            self.comments.insert(start, unused_comments);
        }
    }

    fn print_comment(&mut self, comment: &Comment) {
        let comment_source = comment.span.source_text(self.source_text);
        match comment.kind {
            CommentKind::Line => {
                self.print_str(comment_source);
            }
            CommentKind::Block => {
                // Print block comments with our own indentation.
                let lines = comment_source.split(is_line_terminator);
                for line in lines {
                    if !line.starts_with("/*") {
                        self.print_indent();
                    }
                    self.print_str(line.trim_start());
                    if !line.ends_with("*/") {
                        self.print_hard_newline();
                    }
                }
            }
        }
    }

    pub(crate) fn try_print_eof_legal_comments(&mut self) {
        match self.options.legal_comments.clone() {
            LegalComment::Eof => {
                let comments = self.legal_comments.drain(..).collect::<Vec<_>>();
                for c in comments {
                    self.print_comment(&c);
                    self.print_hard_newline();
                }
            }
            LegalComment::Linked(path) => {
                self.print_str("/*! For license information please see ");
                self.print_str(&path);
                self.print_str(" */");
            }
            _ => {}
        }
    }
}