markdown-code-runner 0.1.0

//! State machine for processing Markdown files.

use anyhow::{bail, Result};
use once_cell::sync::Lazy;
use regex::Regex;
use std::collections::HashMap;
use std::path::PathBuf;

use crate::executor::{execute_code, Language};
use crate::markers::{
    get_indent, is_code_backticks_end, is_code_backticks_start, is_code_comment_bash_start,
    is_code_comment_end, is_code_comment_python_start, is_output_end, is_output_start, is_skip,
    remove_md_comment, WARNING,
};

/// Pattern to extract key=value options from a backtick line.
static OPTION_PATTERN: Lazy<Regex> =
    Lazy::new(|| Regex::new(r"(?P<key>\w+)=(?P<value>\S+)").unwrap());

/// Current section being processed.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Section {
    Normal,
    Output,
    CodeCommentPython,
    CodeCommentBash,
    CodeBackticks,
}

/// Backtick options extracted from the code fence line.
#[derive(Debug, Clone, Default)]
pub struct BacktickOptions {
    pub language: String,
    pub filename: Option<PathBuf>,
    pub other: HashMap<String, String>,
}

impl BacktickOptions {
    /// Extract backtick options from a code fence line.
    pub fn from_line(line: &str) -> Self {
        let mut options = BacktickOptions::default();

        // Extract language
        static LANG_PATTERN: Lazy<Regex> =
            Lazy::new(|| Regex::new(r"```(?P<language>\w+)").unwrap());

        if let Some(caps) = LANG_PATTERN.captures(line) {
            options.language = caps["language"].to_string();
        }

        // Extract key=value options after markdown-code-runner
        if line.contains("markdown-code-runner") {
            for caps in OPTION_PATTERN.captures_iter(line) {
                let key = caps["key"].to_string();
                let value = caps["value"].to_string();
                if key == "filename" {
                    options.filename = Some(PathBuf::from(value));
                } else {
                    options.other.insert(key, value);
                }
            }
        }

        options
    }
}

/// Processing state for the Markdown file.
pub struct ProcessingState {
    /// Current section being processed.
    pub section: Section,
    /// Code lines collected from the current code block.
    pub code: Vec<String>,
    /// Original output lines (preserved when skipping).
    pub original_output: Vec<String>,
    /// Whether to skip the next code block.
    pub skip_code_block: bool,
    /// Output from the last executed code block.
    pub output: Option<Vec<String>>,
    /// New lines being built.
    pub new_lines: Vec<String>,
    /// Options from the current backtick code block.
    pub backtick_options: BacktickOptions,
    /// Whether to standardize backticks (remove markdown-code-runner).
    pub backtick_standardize: bool,
    /// Indentation of the current code block.
    pub indent: String,
    /// Verbose mode for debugging.
    pub verbose: bool,
    /// All Python code blocks seen so far (for context sharing).
    python_blocks: Vec<Vec<String>>,
}

impl ProcessingState {
    /// Create a new processing state.
    pub fn new(backtick_standardize: bool, verbose: bool) -> Self {
        Self {
            section: Section::Normal,
            code: Vec::new(),
            original_output: Vec::new(),
            skip_code_block: false,
            output: None,
            new_lines: Vec::new(),
            backtick_options: BacktickOptions::default(),
            backtick_standardize,
            indent: String::new(),
            verbose,
            python_blocks: Vec::new(),
        }
    }

    /// Process a single line of the Markdown file.
    pub fn process_line(&mut self, line: &str) -> Result<()> {
        if is_skip(line) {
            self.skip_code_block = true;
            self.new_lines.push(line.to_string());
        } else if is_output_start(line).is_some() {
            self.process_output_start(line);
        } else if is_output_end(line) {
            self.process_output_end(line);
        } else {
            match self.section {
                Section::CodeCommentPython | Section::CodeCommentBash => {
                    self.process_comment_code(line)?;
                }
                Section::CodeBackticks => {
                    self.process_backtick_code(line)?;
                }
                Section::Output => {
                    self.original_output.push(line.to_string());
                }
                Section::Normal => {
                    let processed_line = self.process_start_markers(line);
                    self.new_lines
                        .push(processed_line.unwrap_or_else(|| line.to_string()));
                    return Ok(());
                }
            }
            if self.section != Section::Output {
                self.new_lines.push(line.to_string());
            }
        }
        Ok(())
    }

    /// Process start markers (code block starts).
    fn process_start_markers(&mut self, line: &str) -> Option<String> {
        // Check for Python code comment start
        if is_code_comment_python_start(line).is_some() {
            self.output = None;
            self.section = Section::CodeCommentPython;
            self.indent = get_indent(line);
            return Some(line.to_string());
        }

        // Check for Bash code comment start
        if is_code_comment_bash_start(line).is_some() {
            self.output = None;
            self.section = Section::CodeCommentBash;
            self.indent = get_indent(line);
            return Some(line.to_string());
        }

        // Check for backtick code block start
        if let Some(caps) = is_code_backticks_start(line) {
            self.output = None;
            self.backtick_options = BacktickOptions::from_line(line);
            self.section = Section::CodeBackticks;
            self.indent = caps.name("spaces").map_or("", |m| m.as_str()).to_string();

            // Standardize backticks if needed
            if self.backtick_standardize && line.contains("markdown-code-runner") {
                static STRIP_PATTERN: Lazy<Regex> =
                    Lazy::new(|| Regex::new(r"\s+markdown-code-runner.*").unwrap());
                return Some(STRIP_PATTERN.replace(line, "").to_string());
            }
            return Some(line.to_string());
        }

        None
    }

    /// Process output start marker.
    fn process_output_start(&mut self, line: &str) {
        self.section = Section::Output;
        if !self.skip_code_block {
            // Get the output, panicking if it's None (this is a programming error)
            let output = self.output.as_ref().unwrap_or_else(|| {
                panic!("Output must be set before OUTPUT:START, line: {}", line)
            });
            let indent = get_indent(line);

            // Add the output start marker
            self.new_lines.push(line.to_string());

            // Add the warning comment with indentation
            self.new_lines.push(format!("{}{}", indent, WARNING));

            // Add each output line with proper indentation and trailing whitespace trimmed
            for ol in output {
                let trimmed = ol.trim_end();
                if trimmed.is_empty() {
                    self.new_lines.push(String::new());
                } else {
                    self.new_lines.push(format!("{}{}", indent, trimmed));
                }
            }
        } else {
            self.original_output.push(line.to_string());
        }
    }

    /// Process output end marker.
    fn process_output_end(&mut self, line: &str) {
        self.section = Section::Normal;
        if self.skip_code_block {
            self.new_lines.append(&mut self.original_output);
            self.skip_code_block = false;
        }
        self.new_lines.push(line.to_string());
        self.original_output.clear();
        self.output = None;
    }

    /// Strip the code block's indentation prefix from a line.
    fn strip_indent(&self, line: &str) -> String {
        if !self.indent.is_empty() && line.starts_with(&self.indent) {
            line[self.indent.len()..].to_string()
        } else {
            line.to_string()
        }
    }

    /// Process code inside a comment block.
    fn process_comment_code(&mut self, line: &str) -> Result<()> {
        if is_code_comment_end(line) {
            if !self.skip_code_block {
                let language = match self.section {
                    Section::CodeCommentPython => Language::Python,
                    Section::CodeCommentBash => Language::Bash,
                    _ => unreachable!(),
                };
                self.execute_current_block(language)?;
            }
            self.section = Section::Normal;
            self.code.clear();
            self.backtick_options = BacktickOptions::default();
            self.indent.clear();
        } else {
            // Remove markdown comment and add to code
            if let Some(code_line) = remove_md_comment(line) {
                self.code.push(code_line);
            }
        }
        Ok(())
    }

    /// Process code inside a backtick block.
    fn process_backtick_code(&mut self, line: &str) -> Result<()> {
        if is_code_backticks_end(line) {
            if !self.skip_code_block {
                let language = Language::parse(&self.backtick_options.language);
                // Clone the filename to avoid borrow issues
                let output_file = self.backtick_options.filename.clone();

                if language.is_none() && output_file.is_none() {
                    bail!("Specify 'output_file' for non-Python/Bash languages.");
                }

                if let Some(lang) = language {
                    self.execute_current_block_with_file(lang, output_file.as_deref())?;
                } else {
                    // Write to file for non-executable languages
                    let code = self.code.clone();
                    let verbose = self.verbose;
                    self.output = Some(execute_code(
                        &code,
                        Language::Python,
                        output_file.as_deref(),
                        verbose,
                    )?);
                }
            }
            self.section = Section::Normal;
            self.code.clear();
            self.backtick_options = BacktickOptions::default();
            self.indent.clear();
        } else {
            // Strip the block indentation from the code line
            let stripped = self.strip_indent(line);
            self.code.push(stripped);
        }
        Ok(())
    }

    /// Execute the current code block for Python with context sharing.
    fn execute_current_block(&mut self, language: Language) -> Result<()> {
        self.execute_current_block_with_file(language, None)
    }

    /// Execute the current code block with optional output file.
    fn execute_current_block_with_file(
        &mut self,
        language: Language,
        output_file: Option<&std::path::Path>,
    ) -> Result<()> {
        if output_file.is_some() {
            // Write to file, no execution
            self.output = Some(execute_code(
                &self.code,
                language,
                output_file,
                self.verbose,
            )?);
        } else if language == Language::Python {
            // For Python, we need to share context between blocks
            // Add current block to the list of Python blocks
            self.python_blocks.push(self.code.clone());

            // We need to capture only the output from the current block
            // The Python version uses exec() with a shared context, but since we're
            // shelling out, we need to use a different approach.
            //
            // Strategy: Add a marker before the current block's output
            let marker = format!("__MCR_MARKER_{}__", self.python_blocks.len());
            let mut code_with_marker: Vec<String> = Vec::new();

            // Add all previous blocks
            for (i, block) in self.python_blocks.iter().enumerate() {
                if i == self.python_blocks.len() - 1 {
                    // Current block - add marker before it
                    code_with_marker.push(format!("print('{}')", marker));
                }
                code_with_marker.extend(block.iter().cloned());
            }

            let output = execute_code(&code_with_marker, Language::Python, None, self.verbose)?;

            // Extract only the output after our marker
            let mut in_current_block = false;
            let mut current_output: Vec<String> = Vec::new();
            for line in output {
                if line == marker {
                    in_current_block = true;
                } else if in_current_block {
                    current_output.push(line);
                }
            }

            self.output = Some(current_output);
        } else {
            // Bash doesn't need context sharing
            self.output = Some(execute_code(&self.code, language, None, self.verbose)?);
        }
        Ok(())
    }
}

/// Process markdown content and return the modified lines.
pub fn process_markdown(
    content: &[String],
    verbose: bool,
    backtick_standardize: bool,
    execute: bool,
) -> Result<Vec<String>> {
    if !execute {
        return Ok(content.to_vec());
    }

    let mut state = ProcessingState::new(backtick_standardize, verbose);

    for (i, line) in content.iter().enumerate() {
        if verbose {
            eprintln!("\x1b[1mline {:4}\x1b[0m: {}", i, line);
        }
        state.process_line(line)?;
    }

    Ok(state.new_lines)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_backtick_options_from_line() {
        let opts = BacktickOptions::from_line("```python markdown-code-runner filename=test.py");
        assert_eq!(opts.language, "python");
        assert_eq!(opts.filename, Some(PathBuf::from("test.py")));

        let opts = BacktickOptions::from_line("```bash markdown-code-runner");
        assert_eq!(opts.language, "bash");
        assert_eq!(opts.filename, None);

        let opts = BacktickOptions::from_line("```python");
        assert_eq!(opts.language, "python");
        assert_eq!(opts.filename, None);
    }

    #[test]
    fn test_process_simple_python() {
        let input = vec![
            "Some text".to_string(),
            "```python markdown-code-runner".to_string(),
            "print('Hello, world!')".to_string(),
            "```".to_string(),
            "<!-- OUTPUT:START -->".to_string(),
            "old output".to_string(),
            "<!-- OUTPUT:END -->".to_string(),
        ];

        let output = process_markdown(&input, false, false, true).unwrap();
        assert!(output.contains(&"Hello, world!".to_string()));
        assert!(!output.contains(&"old output".to_string()));
    }

    #[test]
    fn test_process_with_skip() {
        let input = vec![
            "<!-- CODE:SKIP -->".to_string(),
            "```python markdown-code-runner".to_string(),
            "print('Hello, world!')".to_string(),
            "```".to_string(),
            "<!-- OUTPUT:START -->".to_string(),
            "old output".to_string(),
            "<!-- OUTPUT:END -->".to_string(),
        ];

        let output = process_markdown(&input, false, false, true).unwrap();
        assert!(output.contains(&"old output".to_string()));
    }

    #[test]
    fn test_process_execute_false() {
        let input = vec![
            "```python markdown-code-runner".to_string(),
            "print('Hello')".to_string(),
            "```".to_string(),
        ];

        let output = process_markdown(&input, false, false, false).unwrap();
        assert_eq!(input, output);
    }
}