extern crate pest;
#[macro_use]
extern crate pest_derive;

use pest::error::Error as PestError;
use pest::error::ErrorVariant;
use pest::Parser;
use pest::iterators::Pairs;
use std::path::PathBuf;

#[derive(Parser)]
#[grammar = "pipeline.pest"]
pub struct PipelineParser;

pub fn parse_file(path: &PathBuf) -> Result<(), pest::error::Error<Rule>> {
    use std::fs::File;
    use std::io::Read;

    match File::open(path) {
        Ok(mut file) => {
            let mut contents = String::new();

            if let Err(e) = file.read_to_string(&mut contents) {
                return Err(PestError::new_from_pos(
                    ErrorVariant::CustomError {
                        message: format!("{}", e),
                    },
                    pest::Position::from_start(""),
                ));
            } else {
                return parse_pipeline_string(&contents);
            }
        }
        Err(e) => {
            return Err(PestError::new_from_pos(
                ErrorVariant::CustomError {
                    message: format!("{}", e),
                },
                pest::Position::from_start(""),
            ));
        }
    }
}

/**
 * Make sure that the stage has the required directives, otherwise throw
 * out a CustomError
 */
fn parse_stage(parser: &mut Pairs<Rule>, span: pest::Span) -> Result<(), PestError<Rule>> {
    let mut met_requirements = false;

    while let Some(parsed) = parser.next() {
        match parsed.as_rule() {
            Rule::stepsDecl => {
                met_requirements = true;
            },
            Rule::parallelDecl => {
                met_requirements = true;
            },
            Rule::stagesDecl => {
                met_requirements = true;
                parse_stages(&mut parsed.into_inner())?;
            }
            _ => {},
        }
    }

    if ! met_requirements {
        Err(PestError::new_from_span(
                ErrorVariant::CustomError {
                    message: "A stage must have either steps{}, parallel{}, or nested stages {}".to_string(),
                }, span
            ))
    }
    else {
        Ok(())
    }
}

fn parse_stages(parser: &mut Pairs<Rule>) -> Result<(), PestError<Rule>> {
    while let Some(parsed) = parser.next() {
        match parsed.as_rule() {
            Rule::stage => {
                let span = parsed.as_span();
                parse_stage(&mut parsed.into_inner(), span)?;
            },
            _ => {},
        }
    }
    Ok(())
}

pub fn parse_pipeline_string(buffer: &str) -> Result<(), PestError<Rule>> {
    let mut parser = PipelineParser::parse(Rule::pipeline, buffer)?;

    let mut agents = false;
    let mut stages = false;

    while let Some(parsed) = parser.next() {
        match parsed.as_rule() {
            Rule::agentDecl => {
                if agents {
                    return Err(PestError::new_from_span(
                        ErrorVariant::CustomError {
                            message: "Cannot have two top-level `agent` directives".to_string(),
                        },
                        parsed.as_span(),
                    ));
                }
                agents = true;
            }
            Rule::stagesDecl => {
                if stages {
                    return Err(PestError::new_from_span(
                        ErrorVariant::CustomError {
                            message: "Cannot have two top-level `stages` directives".to_string(),
                        },
                        parsed.as_span(),
                    ));
                }
                stages = true;
                parse_stages(&mut parsed.into_inner())?;
            }
            _ => {}
        }
    }
    /*
     * Both agents and stages are required, the lack thereof is an error
     */
    if !agents || !stages {
        let error = PestError::new_from_pos(
            ErrorVariant::ParsingError {
                positives: vec![],
                negatives: vec![],
            },
            pest::Position::from_start(buffer),
        );
        return Err(error);
    }

    Ok(())
}

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

    #[test]
    fn parse_string_single() {
        let _str = PipelineParser::parse(Rule::string, r#"'hello world'"#)
            .unwrap()
            .next()
            .unwrap();
    }

    #[test]
    fn parse_string_double() {
        let _str = PipelineParser::parse(Rule::string, r#""hello world""#)
            .unwrap()
            .next()
            .unwrap();
    }

    #[test]
    fn simple_validation() {
        let _pipeline = PipelineParser::parse(
            Rule::pipeline,
            r#"#!/usr/bin/env groovy

pipeline {
    agent any 

    stages {
        stage('Build') { 
            steps {
                sh 'ls -lah'
            }
        }
    }
}
"#,
        )
        .expect("Failed to parse")
        .next()
        .expect("Failed to iterate");
    }

    #[test]
    fn parse_no_options() {
        let _options = PipelineParser::parse(Rule::optionsDecl, "options { }")
            .unwrap()
            .next()
            .unwrap();
    }

    #[test]
    fn parse_options_no_args() {
        let _options = PipelineParser::parse(Rule::optionsDecl, "options { timestamps() }")
            .unwrap()
            .next()
            .unwrap();
    }

    #[test]
    fn parse_options_kwargs() {
        let _options = PipelineParser::parse(
            Rule::optionsDecl,
            "options { timeout(time: 4, unit: 'HOURS') }",
        )
        .unwrap()
        .next()
        .unwrap();
    }

    /*
     * WHY DOES THIS SYNTAX EXIST
     *
     * So annoying. "Declarative"
     */
    #[test]
    fn parse_options_nested_func() {
        let _options = PipelineParser::parse(
            Rule::optionsDecl,
            "options { buildDiscarder(logRotator(daysToKeepStr: '10')) }",
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_options_optional_parens() {
        let _options = PipelineParser::parse(
            Rule::optionsDecl,
            "options { buildDiscarder logRotator(daysToKeepStr: '10') }",
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_triggers() {
        let _t = PipelineParser::parse(Rule::triggersDecl, "triggers { pollSCM('H * * * *') }")
            .unwrap()
            .next()
            .unwrap();
    }

    #[test]
    fn parse_environment() {
        let _e = PipelineParser::parse(
            Rule::environmentDecl,
            r#"environment {
                DISABLE_PROXY_CACHE = 'true'
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_block_steps() {
        let _s = PipelineParser::parse(Rule::step, "dir('foo') { sh 'make' }")
            .unwrap()
            .next()
            .unwrap();
    }

    #[test]
    fn parse_complex_step() {
        let _s = PipelineParser::parse(
            Rule::step,
            r#"checkout([
                $class: 'GitSCM',
                branches: [
                    [name: "refs/heads/${env.BRANCH_NAME}"]
                ],
                gitTool: scm.gitTool,
                extensions: [
                    [name: "refs/heads/${env.BRANCH_NAME}"],
                ],
            ])"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_not_exactly_declarative_is_it_step() {
        let _s = PipelineParser::parse(
            Rule::step,
            r#"checkout([
                $class: 'GitSCM',
                userRemoteConfigs: [
                    [ refspec: scm.userRemoteConfigs[0].refspec,
                      url: scm.userRemoteConfigs[0].url
                    ]
                ],
            ])"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_steps_with_triple_singles() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                sh '''
                    env
                '''
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_steps_with_triple_doubles() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                sh """
                    env
                """
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    /*
     * I kind of cannot believe that this is legitimate Declarative but it
     * apparently is!
     */
    #[test]
    fn parse_string_with_concatenation() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                echo 'Hello world: ' + WORKSPACE
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_step_with_symbol_concatenation() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                ws(dir: WORKSPACE + '/foo') {
                    sh 'pwd'
                }
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_steps_with_parens() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                deleteDir()
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_script_step() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                script {
                    def taskOutput = readJSON file: 'task-output.dev.json'
                    def revision = taskOutput.taskDefinition.revision
                    sh "aws ecs update-service --cluster ${CLUSTER} --service ${SERVICE} --task-definition ${FAMILY}:${revision}"
                }
            }"#)
        .unwrap().next().unwrap();
    }

    #[test]
    fn parse_script_step_nesting() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                script {
                    withAnt(installation: 'ant-latest') {
                        if (isUnix()) {
                            sh 'ant info'
                        }
                        else {
                            bat 'ant info'
                        }
                    }
                }
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    /*
     * I put a step in your step so you can step while you step
     */
    #[test]
    fn parse_sup_dawg_heard_you_liked_steps() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                sh 'rm -f task-definition.*.json'

                writeJSON(file: 'task-definition.dev.json',
                        json: readYaml(text: readFile('deploy/task-definition.yml')))
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }

    #[test]
    fn parse_abusive_chaining_of_groovy_on_steps() {
        let _s = PipelineParser::parse(
            Rule::stepsDecl,
            r#"steps {
                sh 'rm -f task-definition.*.json'

                writeJSON(file: 'task-definition.dev.json',
                        json: readYaml(text: readFile('deploy/task-definition.yml')
                                                    .replaceAll('@@IMAGE@@', params.IMAGE)
                                                    .replaceAll('@@FAMILY@@', params.FAMILY)))
                sh 'echo DEV task definition:'
                sh 'cat task-definition.dev.json'
            }"#,
        )
        .unwrap()
        .next()
        .unwrap();
    }
}