pub mod macros;

use pest::Parser;
use pest_derive::Parser;
use std::collections::HashMap;
use anyhow::{Result};

#[derive(Parser)]
#[grammar = "specfile.pest"]
struct SpecFileParser;

#[derive(Default, Debug)]
pub struct SpecFile {
    pub name: String,
    pub version: String,
    pub release: String,
    pub summary: String,
    pub license: String,
    pub sources: Vec<String>,
    pub variables: HashMap<String, String>,
    pub description: String,
    pub prep_script: String,
    pub build_script: String,
    pub install_script: String,
    pub files: Vec<String>,
    pub changelog: String,
}

enum KnownVariableControl {
    Name,
    Version,
    Release,
    Summary,
    License,
    None,
}

fn append_newline_string(s: &str, section_line: i32) -> String {
    if section_line == 0 {
        return s.to_owned();
    }
    return "\n".to_owned() + s;
}

pub fn parse(file_contents: String) -> Result<SpecFile> {
    let pairs = SpecFileParser::parse(Rule::file, &file_contents)?;
    let mut spec = SpecFile::default();


    for pair in pairs {
        // A pair can be converted to an iterator of the tokens which make it up:
        match pair.as_rule() {
            Rule::variable => {
                let mut var_control = KnownVariableControl::None;
                let mut var_name_tmp = String::new();
                for variable_rule in pair.clone().into_inner() {
                    match variable_rule.as_rule() {
                        Rule::variable_name => {
                            match variable_rule.as_str() {
                                "Name" => var_control = KnownVariableControl::Name,
                                "Version" => var_control = KnownVariableControl::Version,
                                "Release" => var_control = KnownVariableControl::Release,
                                "Summary" => var_control = KnownVariableControl::Summary,
                                "License" => var_control = KnownVariableControl::License,
                                _ => var_control = {
                                    var_name_tmp = variable_rule.as_str().to_string();
                                    KnownVariableControl::None
                                },
                            }
                        }
                        Rule::variable_text => {
                            match var_control {
                                KnownVariableControl::Name => spec.name = variable_rule.as_str().to_string(),
                                KnownVariableControl::Version => spec.version = variable_rule.as_str().to_string(),
                                KnownVariableControl::Release => spec.release = variable_rule.as_str().to_string(),
                                KnownVariableControl::Summary =>spec.summary = variable_rule.as_str().to_string(),
                                KnownVariableControl::License => spec.license = variable_rule.as_str().to_string(),
                                KnownVariableControl::None => {
                                    spec.variables.insert(var_name_tmp.clone(), variable_rule.as_str().to_string());
                                }
                            }
                        }
                        _ => ()
                    }
                }
            }
            Rule::section => {
                let mut section_name_tmp = String::new();
                let mut section_line = 0;
                for section_rule in pair.clone().into_inner() {
                    match section_rule.as_rule() {
                        Rule::section_name => {
                            section_name_tmp = section_rule.as_str().to_string()
                        }
                        Rule::section_line => {
                            for line_or_comment in section_rule.into_inner() {
                                match line_or_comment.as_rule() {
                                    Rule::section_text => {
                                        match section_name_tmp.as_str() {
                                            "description" => {
                                                spec.description.push_str(append_newline_string(line_or_comment.as_str(), section_line).as_str());
                                                section_line = section_line + 1
                                            },
                                            "prep" => {
                                                spec.prep_script.push_str(append_newline_string(line_or_comment.as_str(), section_line).as_str());
                                                section_line = section_line + 1
                                            },
                                            "build" => {
                                                spec.build_script.push_str(append_newline_string(line_or_comment.as_str(), section_line).as_str());
                                                section_line = section_line + 1
                                            },
                                            "files" => spec.files.push(line_or_comment.as_str().trim_end().to_string()),
                                            "install" => {
                                                spec.install_script.push_str(append_newline_string(line_or_comment.as_str(), section_line).as_str());
                                                section_line = section_line + 1
                                            },
                                            "changelog" => {
                                                spec.changelog.push_str(append_newline_string(line_or_comment.as_str(), section_line).as_str());
                                                section_line = section_line + 1
                                            },
                                            _ => panic!(
                                                "Unknown Section: {:?}",
                                                line_or_comment.as_rule()
                                            ),
                                        }
                                    }
                                    _ => ()
                                }
                            }
                        }
                        _ => panic!("Rule not known please update the code: {:?}", section_rule.as_rule()),
                    }
                }
            }
            Rule::EOI => (),
            _ => panic!("Rule not known please update the code: {:?}", pair.as_rule()),
        }
    }

    Ok(spec)
}

#[cfg(test)]
mod tests {
    use std::fs;
    use crate::parse;

    #[test]
    fn it_works() {
        assert_eq!(2 + 2, 4);
    }

    #[test]
    fn test_parse() {
        let contents = fs::read_to_string("src/test_data/simple.spec");
        match contents {
            Ok(file) => {
                let spec = parse(file);
                assert!(spec.is_ok(), "parsing error {:?}", spec)
            },
            Err(e) => panic!("io error: {:}", e)
        }
    }
}