// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

use crate::colors;
use deno_core::error::AnyError;
use deno_core::serde_json;
use deno_core::serde_json::json;
use deno_core::url::Url;
use deno_runtime::inspector::InspectorSession;
use serde::Deserialize;

pub struct CoverageCollector {
  session: Box<InspectorSession>,
}

impl CoverageCollector {
  pub fn new(session: Box<InspectorSession>) -> Self {
    Self { session }
  }

  pub async fn start_collecting(&mut self) -> Result<(), AnyError> {
    self.session.post_message("Debugger.enable", None).await?;

    self.session.post_message("Profiler.enable", None).await?;

    self
      .session
      .post_message(
        "Profiler.startPreciseCoverage",
        Some(json!({"callCount": true, "detailed": true})),
      )
      .await?;

    Ok(())
  }

  pub async fn collect(&mut self) -> Result<Vec<Coverage>, AnyError> {
    let result = self
      .session
      .post_message("Profiler.takePreciseCoverage", None)
      .await?;

    let take_coverage_result: TakePreciseCoverageResult =
      serde_json::from_value(result)?;

    let mut coverages: Vec<Coverage> = Vec::new();
    for script_coverage in take_coverage_result.result {
      let result = self
        .session
        .post_message(
          "Debugger.getScriptSource",
          Some(json!({
              "scriptId": script_coverage.script_id,
          })),
        )
        .await?;

      let get_script_source_result: GetScriptSourceResult =
        serde_json::from_value(result)?;

      coverages.push(Coverage {
        script_coverage,
        script_source: get_script_source_result.script_source,
      })
    }

    Ok(coverages)
  }

  pub async fn stop_collecting(&mut self) -> Result<(), AnyError> {
    self
      .session
      .post_message("Profiler.stopPreciseCoverage", None)
      .await?;
    self.session.post_message("Profiler.disable", None).await?;
    self.session.post_message("Debugger.disable", None).await?;

    Ok(())
  }
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct CoverageRange {
  pub start_offset: usize,
  pub end_offset: usize,
  pub count: usize,
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct FunctionCoverage {
  pub function_name: String,
  pub ranges: Vec<CoverageRange>,
  pub is_block_coverage: bool,
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ScriptCoverage {
  pub script_id: String,
  pub url: String,
  pub functions: Vec<FunctionCoverage>,
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct Coverage {
  pub script_coverage: ScriptCoverage,
  pub script_source: String,
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
struct TakePreciseCoverageResult {
  result: Vec<ScriptCoverage>,
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct GetScriptSourceResult {
  pub script_source: String,
  pub bytecode: Option<String>,
}

pub struct PrettyCoverageReporter {
  quiet: bool,
}

// TODO(caspervonb) add support for lcov output (see geninfo(1) for format spec).
impl PrettyCoverageReporter {
  pub fn new(quiet: bool) -> PrettyCoverageReporter {
    PrettyCoverageReporter { quiet }
  }

  pub fn visit_coverage(&mut self, coverage: &Coverage) {
    let lines = coverage.script_source.lines().collect::<Vec<_>>();

    let mut covered_lines: Vec<usize> = Vec::new();
    let mut uncovered_lines: Vec<usize> = Vec::new();

    let mut line_start_offset = 0;
    for (index, line) in lines.iter().enumerate() {
      let line_end_offset = line_start_offset + line.len();

      let mut count = 0;
      for function in &coverage.script_coverage.functions {
        for range in &function.ranges {
          if range.start_offset <= line_start_offset
            && range.end_offset >= line_end_offset
          {
            if range.count == 0 {
              count = 0;
              break;
            }

            count += range.count;
          }
        }

        line_start_offset = line_end_offset;
      }
      if count > 0 {
        covered_lines.push(index);
      } else {
        uncovered_lines.push(index);
      }
    }

    if !self.quiet {
      print!("cover {} ... ", coverage.script_coverage.url);

      let line_coverage_ratio = covered_lines.len() as f32 / lines.len() as f32;
      let line_coverage = format!(
        "{:.3}% ({}/{})",
        line_coverage_ratio * 100.0,
        covered_lines.len(),
        lines.len()
      );

      if line_coverage_ratio >= 0.9 {
        println!("{}", colors::green(&line_coverage));
      } else if line_coverage_ratio >= 0.75 {
        println!("{}", colors::yellow(&line_coverage));
      } else {
        println!("{}", colors::red(&line_coverage));
      }

      let mut last_line = None;
      for line_index in uncovered_lines {
        const WIDTH: usize = 4;
        const SEPERATOR: &str = "|";

        // Put a horizontal separator between disjoint runs of lines
        if let Some(last_line) = last_line {
          if last_line + 1 != line_index {
            let dash = colors::gray(&"-".repeat(WIDTH + 1));
            println!("{}{}{}", dash, colors::gray(SEPERATOR), dash);
          }
        }

        println!(
          "{:width$} {} {}",
          line_index + 1,
          colors::gray(SEPERATOR),
          colors::red(&lines[line_index]),
          width = WIDTH
        );

        last_line = Some(line_index);
      }
    }
  }
}

pub fn filter_script_coverages(
  coverages: Vec<Coverage>,
  test_file_url: Url,
  test_modules: Vec<Url>,
) -> Vec<Coverage> {
  coverages
    .into_iter()
    .filter(|e| {
      if let Ok(url) = Url::parse(&e.script_coverage.url) {
        if url.path().ends_with("__anonymous__") {
          return false;
        }

        if url == test_file_url {
          return false;
        }

        for test_module_url in &test_modules {
          if &url == test_module_url {
            return false;
          }
        }

        if let Ok(path) = url.to_file_path() {
          for test_module_url in &test_modules {
            if let Ok(test_module_path) = test_module_url.to_file_path() {
              if path.starts_with(test_module_path.parent().unwrap()) {
                return true;
              }
            }
          }
        }
      }

      false
    })
    .collect::<Vec<Coverage>>()
}