use crate::error::Error;
use crate::{error::ApiResult, db};
use chrono::{DateTime, Datelike, NaiveDate, Utc};
use std::collections::{HashMap, HashSet};
use std::env;
use std::fmt::Display;
use std::str::FromStr;
use redis::{AsyncCommands, RedisResult};
use reqwest::Client;
use serde::{Deserialize, Serialize};
use crate::airports::{Airport, UpdateAirport};
use crate::db::redis_async_connection;
use crate::metars::MetarCheck;

const TABLE_NAME: &str = "metars";

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Metar {
  pub icao: String,
  pub raw_text: String,
  pub observation_time: DateTime<Utc>,
  pub flight_category: FlightCategory,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub report_modifier: Option<ReportModifier>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub becoming_change: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub no_significant_change: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub temporary_change: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub temp_c: Option<f64>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub dew_point_c: Option<f64>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub estimated_humidity: Option<f64>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub wind_dir_degrees: Option<String>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub wind_speed_kt: Option<f64>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub wind_gust_kt: Option<f64>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub variable_wind_dir_degrees: Option<String>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub visibility_statute_mi: Option<String>,
  pub runway_visual_range: Vec<RunwayVisualRange>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub altimeter_in_hg: Option<f64>, // inches of mercury units
  #[serde(skip_serializing_if = "Option::is_none")]
  pub sea_level_pressure_mb: Option<f64>,
  pub remarks: Remarks,
  pub weather_phenomena: Vec<String>,
  pub sky_condition: Vec<SkyCondition>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub max_temp_c: Option<f64>, // TODO
  #[serde(skip_serializing_if = "Option::is_none")]
  pub min_temp_c: Option<f64>, // TODO
  #[serde(skip_serializing_if = "Option::is_none")]
  pub density_altitude: Option<f64>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ReportModifier {
  #[serde(rename = "AUTO")]
  Auto,
  #[serde(rename = "COR")]
  Corrected,
}

impl FromStr for ReportModifier {
  type Err = Error;
  fn from_str(s: &str) -> Result<Self, Self::Err> {
    match s {
      "AUTO" => Ok(ReportModifier::Auto),
      "COR" => Ok(ReportModifier::Corrected),
      _ => Err(Error::new(400, format!("Invalid report modifier '{}'", s))),
    }
  }
}

impl Display for ReportModifier {
  fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
    match self {
      ReportModifier::Auto => write!(f, "AUTO"),
      ReportModifier::Corrected => write!(f, "COR"),
    }
  }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RunwayVisualRange {
  pub runway: String,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub visibility_ft: Option<String>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub variable_visibility_low_ft: Option<String>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub variable_visibility_high_ft: Option<String>,
}

impl Default for RunwayVisualRange {
  fn default() -> Self {
    RunwayVisualRange {
      runway: "".to_string(),
      visibility_ft: None,
      variable_visibility_low_ft: None,
      variable_visibility_high_ft: None,
    }
  }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AutomatedStationType {
  #[serde(rename = "AO1")]
  WithoutPrecipitationDiscriminator,
  #[serde(rename = "AO2")]
  WithPrecipitationDiscriminator,
}

impl FromStr for AutomatedStationType {
  type Err = Error;
  fn from_str(s: &str) -> Result<Self, Self::Err> {
    match s {
      "AO1" => Ok(AutomatedStationType::WithoutPrecipitationDiscriminator),
      "AO2" => Ok(AutomatedStationType::WithPrecipitationDiscriminator),
      _ => Err(Error::new(
        400,
        format!("Invalid automated station type '{}'", s),
      )),
    }
  }
}

impl Display for AutomatedStationType {
  fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
    match self {
      AutomatedStationType::WithoutPrecipitationDiscriminator => write!(f, "AO1"),
      AutomatedStationType::WithPrecipitationDiscriminator => write!(f, "AO2"),
    }
  }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Remarks {
  #[serde(skip_serializing_if = "Option::is_none")]
  pub peak_wind: Option<PeakWind>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub auto_station_type: Option<AutomatedStationType>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub maintenance_indicator: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub rvr_missing: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub precipitation_identifier_information_not_available: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub precipitation_information_not_available: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub freezing_rain_information_not_available: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub thunderstorm_information_not_available: Option<bool>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub visibility_at_secondary_location_not_available: Option<String>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub sky_condition_at_secondary_location_not_available: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PeakWind {
  pub degrees: i32,
  pub speed: i32,
  pub hour: Option<i32>,
  pub minutes: i32,
}

impl Default for Remarks {
  fn default() -> Self {
    Remarks {
      peak_wind: None,
      auto_station_type: None,
      maintenance_indicator: None,
      rvr_missing: None,
      precipitation_identifier_information_not_available: None,
      precipitation_information_not_available: None,
      freezing_rain_information_not_available: None,
      thunderstorm_information_not_available: None,
      visibility_at_secondary_location_not_available: None,
      sky_condition_at_secondary_location_not_available: None,
    }
  }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SkyCondition {
  pub sky_cover: String,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub cloud_base_ft_agl: Option<i32>,
  #[serde(skip_serializing_if = "Option::is_none")]
  pub significant_convective_clouds: Option<String>,
}

impl Default for SkyCondition {
  fn default() -> Self {
    SkyCondition {
      sky_cover: "".to_string(),
      cloud_base_ft_agl: None,
      significant_convective_clouds: None,
    }
  }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum FlightCategory {
  VFR,
  MVFR,
  LIFR,
  IFR,
  UNKN,
}

impl Default for Metar {
  fn default() -> Self {
    Self {
      raw_text: "".to_string(),
      icao: "".to_string(),
      observation_time: chrono::DateTime::parse_from_rfc3339("1970-01-01T00:00:00Z")
        .unwrap()
        .with_timezone(&Utc),
      flight_category: FlightCategory::UNKN,
      report_modifier: None,
      no_significant_change: None,
      temporary_change: None,
      becoming_change: None,
      temp_c: None,
      dew_point_c: None,
      wind_dir_degrees: None,
      wind_speed_kt: None,
      wind_gust_kt: None,
      variable_wind_dir_degrees: None,
      visibility_statute_mi: None,
      runway_visual_range: vec![],
      altimeter_in_hg: None,
      sea_level_pressure_mb: None,
      remarks: Remarks::default(),
      weather_phenomena: vec![],
      sky_condition: vec![],
      max_temp_c: None,
      min_temp_c: None,
      estimated_humidity: None,
      density_altitude: None,
    }
  }
}

#[derive(Serialize, Deserialize, sqlx::FromRow, Debug)]
struct MetarRow {
  icao: String,
  observation_time: DateTime<Utc>,
  raw_text: String,
  data: serde_json::Value,
}

impl MetarRow {
  async fn insert(&self) -> ApiResult<()> {
    let pool = db::pool();
    sqlx::query(&format!(
      r#"
      INSERT INTO {} (
        icao,
        observation_time,
        raw_text,
        data
      )
      VALUES ($1, $2, $3, $4)
      ON CONFLICT (icao, observation_time) DO UPDATE SET
        raw_text = EXCLUDED.raw_text,
        data = EXCLUDED.data
      "#,
      TABLE_NAME,
    ))
    .bind(self.icao.clone())
    .bind(self.observation_time.clone())
    .bind(self.raw_text.clone())
    .bind(self.data.clone())
    .execute(pool)
    .await?;

    Ok(())
  }
}

impl Metar {
  fn parse_multiple(metar_strings: &Vec<&str>) -> ApiResult<Vec<Self>> {
    let mut metars: Vec<Metar> = vec![];
    for metar_string in metar_strings {
      match Metar::parse(metar_string) {
        Ok(metar) => metars.push(metar),
        Err(e) => {
          log::warn!("Failed to parse metar string: {}", e);
          continue;
        }
      };
    }

    Ok(metars)
  }

  fn parse(metar_string: &str) -> ApiResult<Self> {
    if metar_string.is_empty() {
      return Err(Error::new(
        404,
        "Unable to parse empty METAR data".to_string(),
      ));
    }

    log::trace!("Parsing METAR data: {}", metar_string);
    let mut metar: Metar = Metar::default();
    metar.raw_text = metar_string.to_owned();
    let mut metar_parts: Vec<&str> = metar_string.split_whitespace().collect();
    if metar_parts.len() < 4 {
      return Err(Error::new(
        500,
        format!(
          "Unable to parse METAR data in an unexpected format: {}",
          metar_string
        ),
      ));
    }

    // Remove METAR at start of text
    if metar_parts[0].to_string() == "METAR".to_string() {
      metar_parts.remove(0);
    }

    // Station Identifier
    metar.icao = metar_parts[0].to_string();
    metar_parts.remove(0);

    // Date/Time
    let observation_time = metar_parts[0];
    metar_parts.remove(0);
    let observation_time = Self::parse_time(observation_time)?;
    metar.observation_time = match chrono::DateTime::parse_from_rfc3339(&observation_time) {
      Ok(datetime) => datetime.with_timezone(&Utc),
      Err(err) => return Err(err.into()),
    };

    loop {
      if metar_parts.is_empty() {
        break;
      }
      // Report Modifiers
      if !metar_parts.is_empty() && (metar_parts[0] == "AUTO" || metar_parts[0] == "COR") {
        metar.report_modifier = Some(ReportModifier::from_str(metar_parts[0])?);
        metar_parts.remove(0);
      }
      if !metar_parts.is_empty() && metar_parts[0] == "NOSIG" {
        metar.no_significant_change = Some(true);
        metar_parts.remove(0);
      }

      // Wind Direction and Speed
      let wind_re = regex::Regex::new(r"^(?:[0-9]{3}|VRB)[0-9]{2}(?:KT|MPS)$").unwrap();
      let wind_gust_re =
        regex::Regex::new(r"^(?:[0-9]{3}|VRB)[0-9]{2}G[0-9]{2}(?:KT|MPS)$").unwrap();
      // Handle input error where there is a space between the numbers and units
      let mut value: Option<String> = None;
      if metar_parts.len() >= 2
        && metar_parts[0].len() == 5
        && (metar_parts[1] == "KT" || metar_parts[1] == "MPS")
      {
        value = Some(format!("{}{}", metar_parts[0], metar_parts[1]));
        metar_parts.remove(0);
        metar_parts.remove(0);
      } else if metar_parts.len() >= 2
        && metar_parts[0].len() == 7
        && metar_parts[0].contains("G")
        && (metar_parts[1] == "KT" || metar_parts[1] == "MPS")
      {
        value = Some(format!("{}{}", metar_parts[0], metar_parts[1]));
        metar_parts.remove(0);
        metar_parts.remove(0);
      } else if !metar_parts.is_empty() && wind_re.is_match(metar_parts[0]) {
        value = Some(metar_parts[0].to_string());
        metar_parts.remove(0);
      } else if !metar_parts.is_empty() && wind_gust_re.is_match(metar_parts[0]) {
        value = Some(metar_parts[0].to_string());
        metar_parts.remove(0);
      }

      match value {
        Some(wind) => {
          if wind_re.is_match(&wind) {
            let wind_dir_degrees = &wind[0..3];
            metar.wind_dir_degrees = Some(wind_dir_degrees.to_string());
            let mut wind_speed_kt = wind[3..5].to_string();
            // Convert m/s to kt
            if wind.len() == 8 {
              wind_speed_kt = (wind_speed_kt.parse::<f64>().unwrap() * 1.94384).to_string();
            }
            metar.wind_speed_kt = Some(wind_speed_kt.parse::<f64>().unwrap());
          } else if wind_gust_re.is_match(&wind) {
            let wind_dir_degrees = &wind[0..3];
            metar.wind_dir_degrees = Some(wind_dir_degrees.to_string());
            let mut wind_speed_kt = wind[3..5].to_string();
            let mut wind_gust_kt = wind[6..8].to_string();
            // Convert m/s to kt
            if wind.len() == 9 {
              wind_speed_kt = (wind_speed_kt.parse::<f64>().unwrap() * 1.94384).to_string();
              wind_gust_kt = (wind_gust_kt.parse::<f64>().unwrap() * 1.94384).to_string();
            }
            metar.wind_speed_kt = Some(wind_speed_kt.parse::<f64>().unwrap());
            metar.wind_gust_kt = Some(wind_gust_kt.parse::<f64>().unwrap());
          }
        }
        None => {}
      }

      // Variable Wind Direction
      let variable_wind_re = regex::Regex::new(r"^[0-9]{3}V[0-9]{3}$").unwrap();
      if !metar_parts.is_empty() && variable_wind_re.is_match(metar_parts[0]) {
        metar.variable_wind_dir_degrees = Some(metar_parts[0].to_string());
        metar_parts.remove(0);
      }

      // Visibility
      let visibility_re = regex::Regex::new(r"^M?(?:[0-9]+|[0-9]+/[0-9]+)SM$").unwrap();
      let visibility_re_m = regex::Regex::new(r"^[0-9]{4}(:?N|NE|NW|S|SE|SW)?$").unwrap();
      if !metar_parts.is_empty() && visibility_re.is_match(metar_parts[0]) {
        let visibility_str = &metar_parts[0][0..metar_parts[0].len() - 2];
        metar_parts.remove(0);
        let visibility: String = if visibility_str.contains("/") {
          let visibility_parts: Vec<&str> = visibility_str.split("/").collect();
          let visibility_left = visibility_parts[0];
          let visibility_right = visibility_parts[1].parse::<f64>()?;
          if visibility_left.starts_with("M") {
            format!(
              "M{}",
              visibility_left[1..visibility_left.len()].parse::<f64>()? / visibility_right
            )
          } else if visibility_left.starts_with("P") {
            format!(
              "P{}",
              visibility_left[1..visibility_left.len()].parse::<f64>()? / visibility_right
            )
          } else {
            format!("{}", visibility_left.parse::<f64>()? / visibility_right)
          }
        } else {
          visibility_str.to_string()
        };
        metar.visibility_statute_mi = Some(visibility);
      } else if !metar_parts.is_empty()
        && metar_parts[0].parse::<f64>().is_ok()
        && metar_parts.len() > 1
        && visibility_re.is_match(metar_parts[1])
      {
        let visibility_whole = metar_parts[0].parse::<f64>()?;
        metar_parts.remove(0);
        let visibility_parts: Vec<&str> = metar_parts[0].split("/").collect();
        metar_parts.remove(0);
        let visibility_left = visibility_parts[0];
        let visibility_right =
          visibility_parts[1][0..visibility_parts[1].len() - 2].parse::<f64>()?;
        let visibility = if visibility_left.starts_with("M") {
          format!(
            "M{}",
            visibility_whole
              + (visibility_left[1..visibility_left.len()].parse::<f64>()? / visibility_right)
          )
        } else if visibility_left.starts_with("P") {
          format!(
            "P{}",
            visibility_whole
              + (visibility_left[1..visibility_left.len()].parse::<f64>()? / visibility_right)
          )
        } else {
          format!(
            "{}",
            visibility_whole + (visibility_left.parse::<f64>()? / visibility_right)
          )
        };
        metar.visibility_statute_mi = Some(visibility);
      } else if !metar_parts.is_empty() && visibility_re_m.is_match(metar_parts[0]) {
        // Convert meters to statute miles
        let visibility = metar_parts[0];
        metar_parts.remove(0);
        if &visibility[0..4] == "9999" {
          metar.visibility_statute_mi = Some("P10".to_string());
        } else {
          let visibility = visibility[0..4].parse::<f64>()? * 0.000621371;
          metar.visibility_statute_mi = Some(format!("{:.2}", visibility));
        }
      }

      // Runway Visual Range
      let rvr_re = regex::Regex::new(r"^R[0-9]{1,3}(?:L|R|C)?/[PM]?[0-9]{4}FT$").unwrap();
      let variable_rvr_re =
        regex::Regex::new(r"^R[0-9]{1,3}(?:L|R|C)?/[PM]?[0-9]{4}V[PM]?[0-9]{4}FT$").unwrap();
      while !metar_parts.is_empty()
        && (rvr_re.is_match(metar_parts[0]) || variable_rvr_re.is_match(metar_parts[0]))
      {
        let rvr_string = metar_parts[0];
        metar_parts.remove(0);
        let mut rvr = RunwayVisualRange::default();
        let rvr_parts: Vec<&str> = rvr_string.split("/").collect();
        rvr.runway = rvr_parts[0].to_string();
        if rvr_re.is_match(rvr_string) {
          rvr.visibility_ft = Some(rvr_parts[1].to_string());
        } else {
          let rvr_variable_parts: Vec<&str> = rvr_parts[1].split("V").collect();
          if rvr_variable_parts.len() != 2 {
            log::warn!(
              "Unable to parse runway visual range in {}: {}",
              rvr_string,
              metar_string
            );
          } else {
            rvr.variable_visibility_low_ft = Some(rvr_variable_parts[0].to_string());
            rvr.variable_visibility_high_ft = Some(rvr_variable_parts[1].to_string());
          }
        }
      }

      // Weather Phenomena
      let wx_intensity = "(?:[+-]|VC)?";
      let wx_descriptor = "(?:MI|PR|BC|DR|BL|SH|TS|FZ)?";
      let wx_precipitation =
        "(?:DZ|RA|SN|SG|IC|PL|GR|GS|UP|BR|FG|FU|VA|DU|SA|HZ|PY|PO|SQ|FC|SS|DS)?";
      let wx_re = regex::Regex::new(&format!(
        r"^{}{}{}$",
        wx_intensity, wx_descriptor, wx_precipitation
      ))
      .unwrap();
      while !metar_parts.is_empty() && wx_re.is_match(metar_parts[0]) {
        metar.weather_phenomena.push(metar_parts[0].to_string());
        metar_parts.remove(0);
      }

      // Sky Condition
      if !metar_parts.is_empty() && metar_parts[0] == "CAVOK" {
        metar.sky_condition.push(SkyCondition {
          sky_cover: "CLR".to_string(),
          cloud_base_ft_agl: None,
          significant_convective_clouds: None,
        });
        metar_parts.remove(0);
      }
      let sky_condition_re =
        regex::Regex::new(r"^(?:CLR|SKC|NSC|NCD|(?:FEW|SCT|BKN|OVC|VV)([0-9/]{3})?(?:CB|TCU)?)$")
          .unwrap();
      while !metar_parts.is_empty() && sky_condition_re.is_match(metar_parts[0]) {
        let sky_condition_string = metar_parts[0];
        metar_parts.remove(0);
        let mut sky_condition = SkyCondition::default();
        let mut vv_offset = 0;
        if &sky_condition_string[0..2] == "VV" {
          sky_condition.sky_cover = "VV".to_string();
          vv_offset = 1;
        } else {
          sky_condition.sky_cover = sky_condition_string[0..3].to_string();
        }
        if sky_condition_string.len() > 3 - vv_offset {
          // Parse out the next three digits
          let cloud_base_ft_agl = &sky_condition_string[3 - vv_offset..6 - vv_offset];
          if cloud_base_ft_agl == "///" {
            sky_condition.cloud_base_ft_agl = None;
          } else {
            sky_condition.cloud_base_ft_agl = match cloud_base_ft_agl.parse::<i32>() {
              Ok(c) => Some(c * 100),
              Err(err) => {
                log::warn!(
                  "Unable to parse cloud base in {}: {}",
                  sky_condition_string,
                  err
                );
                None
              }
            };
          }
          if sky_condition_string.len() > 6 - vv_offset {
            // Parse out the next two digits
            let scc = &sky_condition_string[6 - vv_offset..8 - vv_offset];
            sky_condition.significant_convective_clouds = Some(scc.to_string());
          }
        }
        metar.sky_condition.push(sky_condition);
      }

      // Temperature and Dewpoint
      let temp_re = regex::Regex::new(r"^(?:M?[0-9]{2})?/(?:M?[0-9]{2})?$").unwrap();
      if !metar_parts.is_empty() && temp_re.is_match(metar_parts[0]) {
        let temp_string = metar_parts[0];
        metar_parts.remove(0);
        let temp_parts: Vec<&str> = temp_string.split("/").collect();
        let mut temp_c = "";
        let mut dewpoint_c = "";
        if temp_parts.len() != 2 {
          if temp_string.ends_with("/") {
            temp_c = temp_parts[0];
          } else {
            dewpoint_c = temp_parts[0];
          }
        } else {
          temp_c = temp_parts[0];
          dewpoint_c = temp_parts[1];
        }
        if temp_c.starts_with("M") {
          metar.temp_c = Some(temp_c[1..temp_c.len()].parse::<f64>()? * -1.0);
        } else if !temp_c.is_empty() {
          metar.temp_c = match temp_c.parse::<f64>() {
            Ok(t) => Some(t),
            Err(err) => {
              log::warn!("Unable to parse temperature in {}: {}", temp_c, err);
              None
            }
          };
        }
        if dewpoint_c.starts_with("M") {
          metar.dew_point_c = Some(dewpoint_c[1..dewpoint_c.len()].parse::<f64>()? * -1.0);
        } else if !dewpoint_c.is_empty() {
          metar.dew_point_c = match dewpoint_c.parse::<f64>() {
            Ok(d) => Some(d),
            Err(err) => {
              log::warn!("Unable to parse dewpoint in {}: {}", dewpoint_c, err);
              None
            }
          };
        }
      }

      // Altimeter
      let altim_re = regex::Regex::new(r"^A[0-9]{4}$").unwrap();
      if !metar_parts.is_empty() && altim_re.is_match(metar_parts[0]) {
        let altim = metar_parts[0];
        metar_parts.remove(0);
        metar.altimeter_in_hg = Some(altim[1..altim.len()].parse::<f64>()? / 100.0);
      }

      // Pressure
      let pressure_re = regex::Regex::new(r"^Q[0-9]{4}$").unwrap();
      if !metar_parts.is_empty() && pressure_re.is_match(metar_parts[0]) {
        let pressure = metar_parts[0];
        metar_parts.remove(0);
        metar.sea_level_pressure_mb = Some(pressure[1..pressure.len()].parse::<f64>()?);
      }

      // Trend forecast - becoming change
      if !metar_parts.is_empty() && metar_parts[0] == "BECMG" {
        metar.becoming_change = Some(true);
        metar_parts.remove(0);
      }

      // Trend forecast - temporary change
      if !metar_parts.is_empty() && metar_parts[0] == "TEMPO" {
        metar.temporary_change = Some(true);
        metar_parts.remove(0);
      }

      // Trend forecast - No significant change
      if !metar_parts.is_empty() && metar_parts[0] == "NOSIG" {
        metar.no_significant_change = Some(true);
        metar_parts.remove(0);
      }

      // Remarks
      if !metar_parts.is_empty() && metar_parts[0] == "RMK" {
        metar_parts.remove(0);
        loop {
          if metar_parts.is_empty() {
            break;
          }
          let slp_re = regex::Regex::new(r"^SLP([0-9]{3})$").unwrap();
          let hourly_temp_re = regex::Regex::new(r"^T[01][0-9]{3}[01][0-9]{3}$").unwrap();
          let remark = metar_parts[0];
          metar_parts.remove(0);
          if remark == "AO1" || remark == "AO2" {
            metar.remarks.auto_station_type = Some(AutomatedStationType::from_str(remark)?);
          } else if remark == "$" {
            metar.remarks.maintenance_indicator = Some(true);
          } else if remark == "PK" && metar_parts.len() >= 2 && metar_parts[0] == "WND" {
            metar_parts.remove(0);
            let string = metar_parts[0];
            metar_parts.remove(0);
            let re = regex::Regex::new(
              r"(?<degrees>\d{3})(?<speed>\d{2,3})/(?:(?<hour>\d{2}))?(?<minutes>\d{2})",
            )
            .unwrap();
            if let Some(caps) = re.captures(string) {
              // Get degrees, speed, minutes
              let degrees: i32 = caps["degrees"].parse()?;
              let speed: i32 = caps["speed"].parse()?;
              let minutes: i32 = caps["minutes"].parse()?;

              // Get optional hours
              let hour = if let Some(hour_match) = caps.name("hour") {
                Some(hour_match.as_str().parse()?)
              } else {
                None
              };
              metar.remarks.peak_wind = Some(PeakWind {
                degrees,
                speed,
                hour,
                minutes,
              });
            } else {
              return Err(Error::new(
                500,
                "Input string format is invalid".to_string(),
              ));
            }
          } else if remark == "PNO" {
            metar.remarks.precipitation_information_not_available = Some(true);
          } else if remark == "RVRNO" {
            metar.remarks.rvr_missing = Some(true);
          } else if remark == "PWINO" {
            metar
              .remarks
              .precipitation_identifier_information_not_available = Some(true);
          } else if remark == "FZRANO" {
            metar.remarks.freezing_rain_information_not_available = Some(true);
          } else if remark == "TSNO" {
            metar.remarks.thunderstorm_information_not_available = Some(true);
          } else if remark == "VISNO" {
            let location = metar_parts[0];
            metar_parts.remove(0);
            metar.remarks.visibility_at_secondary_location_not_available =
              Some(location.to_string());
          } else if remark == "CHINO" {
            let location = metar_parts[0];
            metar_parts.remove(0);
            metar
              .remarks
              .sky_condition_at_secondary_location_not_available = Some(location.to_string());
          } else if slp_re.is_match(remark) {
            let slp = slp_re.captures(remark).unwrap();
            let sea_level_pressure = slp[1].parse::<f64>()?;
            if sea_level_pressure > 500.0 {
              metar.sea_level_pressure_mb = Some((sea_level_pressure / 10.0) + 900.0);
            } else {
              metar.sea_level_pressure_mb = Some((sea_level_pressure / 10.0) + 1000.0);
            }
          } else if hourly_temp_re.is_match(remark) {
            let temp_negation = &remark[1..2];
            let temp = &remark[2..5];
            if let Ok(t) = temp.parse::<f64>() {
              if temp_negation == "0" {
                metar.temp_c = Some(t / 10.0);
              } else {
                metar.temp_c = Some(t / 10.0 * -1.0);
              }
            }
            let dewpoint_negation = &remark[5..6];
            let dewpoint = &remark[6..9];
            if let Ok(d) = dewpoint.parse::<f64>() {
              if dewpoint_negation == "0" {
                metar.dew_point_c = Some(d / 10.0);
              } else {
                metar.dew_point_c = Some(d / 10.0 * -1.0);
              }
            }
          }
        }
      }

      // Skip unexpected fields
      if !metar_parts.is_empty() {
        log::warn!(
          "Skipping unexpected field: '{}' ({})",
          metar_parts[0],
          metar_string
        );
        metar_parts.remove(0);
      }
    }

    // Flight Category
    if metar.visibility_statute_mi.is_none() && metar.sky_condition.is_empty() {
      metar.flight_category = FlightCategory::UNKN;
    } else {
      let visibility = match &metar.visibility_statute_mi {
        Some(v) => {
          if v.starts_with("M") || v.starts_with("P") {
            v[1..v.len()].parse::<f64>()?
          } else {
            v.parse::<f64>()?
          }
        }
        None => 5.0, // Assume VFR if no visibility is present
      };
      // Ceiling is the lowest cloud base that is BKN or OVC
      let ceiling = match metar.sky_condition.first() {
        Some(s) => {
          if s.sky_cover == "VV" {
            0.0
          } else if s.sky_cover == "BKN" || s.sky_cover == "OVC" {
            match s.cloud_base_ft_agl {
              Some(c) => c as f64,
              None => 0.0,
            }
          } else {
            3000.0 // Assume VFR if no BKN or OVC sky condition is present
          }
        }
        None => 3000.0, // Assume VFR if no sky condition is present
      };
      if visibility >= 5.0 && ceiling >= 3000.0 {
        metar.flight_category = FlightCategory::VFR;
      } else if visibility >= 3.0 && ceiling >= 1000.0 {
        metar.flight_category = FlightCategory::MVFR;
      } else if visibility >= 1.0 && ceiling >= 500.0 {
        metar.flight_category = FlightCategory::IFR;
      } else {
        metar.flight_category = FlightCategory::LIFR;
      }
    }

    // Calculate estimated humidity using the magnus formula
    if metar.temp_c.is_some() && metar.dew_point_c.is_some() {
      let temp = metar.temp_c.unwrap();
      let dew_point = metar.dew_point_c.unwrap();
      let a: f64 = 17.625;
      let b: f64 = 243.04;
      let exponent_temp = a * temp / (b + temp);
      let exponent_dew = a * dew_point / (b + dew_point);
      let mut estimated_humidity = 100.0 * (exponent_dew.exp() / exponent_temp.exp());
      // Round to 3 decimal places
      estimated_humidity = (estimated_humidity * 1000.0).round() / 1000.0;
      metar.estimated_humidity = Some(estimated_humidity);
    }

    // Calculate estimated density
    // let estimated_density = ;
    // metar.density_altitude = Some(metar.density_altitude);

    // Update the airport's metar observation time
    let icao = metar.icao.clone();
    let observation_time = metar.observation_time.clone();
    tokio::spawn(async move {
      match Airport::update(
        &icao,
        &UpdateAirport {
          icao: None,
          iata: None,
          local: None,
          name: None,
          category: None,
          iso_country: None,
          iso_region: None,
          municipality: None,
          elevation_ft: None,
          longitude: None,
          latitude: None,
          has_tower: None,
          has_beacon: None,
          runways: None,
          frequencies: None,
          public: None,
          latest_metar_observation: Some(observation_time),
        },
      )
      .await
      {
        Ok(_) => {}
        Err(err) => log::error!(
          "Unable to update airport {} with the latest observation time: {}",
          icao,
          err
        ),
      };
    });

    Ok(metar)
  }

  fn parse_time(observation_time: &str) -> ApiResult<String> {
    if observation_time.len() != 7 {
      return Err(Error::new(
        500,
        format!("Unable to parse observation time in {}", observation_time),
      ));
    }
    let observation_day = match observation_time[0..2].parse::<u32>() {
      Ok(day) => day,
      Err(err) => return Err(err.into()),
    };
    let observation_hour = match observation_time[2..4].parse::<u32>() {
      Ok(hour) => hour,
      Err(err) => return Err(err.into()),
    };
    let observation_minute = match observation_time[4..6].parse::<u32>() {
      Ok(minute) => minute,
      Err(err) => return Err(err.into()),
    };
    let current_time = Utc::now().naive_utc();
    let current_year = current_time.year();
    let current_month = current_time.month();
    let candidate_date = NaiveDate::from_ymd_opt(current_year, current_month, observation_day)
      .ok_or_else(|| {
        Error::new(
          500,
          format!(
            "Invalid date with day {} for current month",
            observation_day
          ),
        )
      })?
      .and_hms_opt(observation_hour, observation_minute, 0)
      .unwrap();

    let obs_datetime = if candidate_date > current_time {
      // Subtract one month. (Handle year rollover carefully.)
      let (month, year) = if current_month == 1 {
        (12, current_year - 1)
      } else {
        (current_month - 1, current_year)
      };

      let adjusted_date =
        NaiveDate::from_ymd_opt(year, month, observation_day).ok_or_else(|| {
          Error::new(
            500,
            format!(
              "Invalid date with day {} for month {}",
              observation_day, month
            ),
          )
        })?;
      adjusted_date.and_hms(observation_hour, observation_minute, 0)
    } else {
      candidate_date
    };
    Ok(obs_datetime.format("%Y-%m-%dT%H:%M:00Z").to_string())
  }

  async fn get_remote_metars(client: &Client, icaos: &Vec<String>) -> ApiResult<Vec<Metar>> {
    let base_url = env::var("AVIATION_WEATHER_URL").expect("AVIATION_WEATHER_URL must be set");
    // Query the remote API for the missing METAR data 10 at a time
    let icao_chunks = icaos
      .chunks(10)
      .map(|chunk| chunk.join(","))
      .collect::<Vec<String>>();
    let mut metars: Vec<Metar> = vec![];
    for icao_chunk in icao_chunks {
      let url = format!(
        "{}/metar?ids={}&hours=0&order=id,-obs",
        base_url, icao_chunk
      );
      let mut m = match client.get(url).send().await {
        Ok(r) => {
          // Check if the status code is 200
          if r.status() != 200 {
            return Err(Error::new(
              500,
              format!("Request returned status {}", r.status()),
            ));
          }
          match r.text().await {
            Ok(r) => {
              let metar_chunk = r
                .trim()
                .split("\n")
                .filter(|m| !m.trim().is_empty())
                .collect();
              match Self::parse_multiple(&metar_chunk) {
                Ok(m) => m,
                Err(err) => return Err(err),
              }
            }
            Err(err) => return Err(Error::new(500, format!("METAR parse failed: {}", err))),
          }
        }
        Err(err) => return Err(err.into()),
      };
      metars.append(&mut m);
    }
    Ok(metars)
  }

  fn from_db(metar_db: MetarRow) -> ApiResult<Metar> {
    let metar: Metar = serde_json::from_value(metar_db.data)?;
    Ok(metar)
  }

  fn to_db(&self) -> ApiResult<MetarRow> {
    let data = serde_json::to_value(self)?;
    Ok(MetarRow {
      icao: self.icao.clone(),
      observation_time: self.observation_time,
      raw_text: self.raw_text.clone(),
      data,
    })
  }

  pub async fn find_all_distinct(client: &Client, icao_list: &Vec<String>) -> ApiResult<Vec<Self>> {
    if icao_list.is_empty() {
      return Ok(Vec::new());
    }

    let pool = db::pool();
    let metar_rows: Vec<MetarRow> = sqlx::query_as::<_, MetarRow>(&format!(
      r#"
      SELECT DISTINCT ON (icao) * FROM {}
      WHERE icao = ANY($1)
      ORDER BY icao, observation_time DESC
      "#,
      TABLE_NAME
    ))
    .bind(icao_list)
    .fetch_all(pool)
    .await?;

    let current_time = Utc::now().timestamp();
    let time_offset = env::var("API_METAR_TIME_OFFSET")
      .unwrap_or("1800".to_string())
      .parse::<i64>()
      .unwrap_or(1800);
    let short_time_offset: i64 = 300;

    // Setup metars and missing metar structures
    let mut metars: Vec<Metar> = vec![];
    let mut missing_metar_icaos: Vec<String> = vec![];
    let mut found_metar_icaos: HashSet<String> = HashSet::new();
    let mut requested_icaos: HashSet<String> = HashSet::from_iter(icao_list.clone());

    // Iterate over returned database metars
    for metar_row in metar_rows {
      let icao = metar_row.icao.clone();
      // Remove icao from requested icaos
      requested_icaos.remove(&icao);

      // Handle outdated metars
      if current_time > (metar_row.observation_time.timestamp() + time_offset) {
        let refresh_seconds = match MetarCheck::get(&icao).await {
          Some(c) => current_time - c.updated_at.timestamp(),
          None => short_time_offset,
        };
        // If the metar was cached more than short_time_offset minutes ago, refresh it
        if refresh_seconds >= short_time_offset {
          log::trace!("{} METAR data is outdated, marked for refresh", &icao);
          missing_metar_icaos.push(icao.clone());
        }
        // Otherwise return outdated data and wait
        else {
          log::trace!(
            "{} METAR data is outdated; refreshing in {} seconds",
            &icao,
            short_time_offset - refresh_seconds
          );
          metars.push(Metar::from_db(metar_row)?)
        }
      }
      // Otherwise add the metar to the vector
      else {
        found_metar_icaos.insert(icao.clone());
        let metar_check = MetarCheck::new(icao, true).await;
        metar_check.insert(time_offset as u64).await?;
        metars.push(Metar::from_db(metar_row)?);
      }
    }

    // Add all metars that were not in the returned database metars
    for icao in &requested_icaos {
      match MetarCheck::get(icao).await {
        Some(c) => {
          if current_time > (c.updated_at.timestamp() + short_time_offset) {
            missing_metar_icaos.push(icao.to_string());
          }
        }
        None => {
          missing_metar_icaos.push(icao.to_string());
        }
      }
    }

    if !missing_metar_icaos.is_empty() {
      log::trace!(
        "Retrieving missing METAR data for {:?}",
        missing_metar_icaos
      );
      let mut remote_metars = Self::get_remote_metars(client, &missing_metar_icaos)
        .await
        .unwrap_or_else(|err| {
          log::warn!("Unable to get remote METAR data; {}", err);
          vec![]
        });

      if remote_metars.len() > 0 {
        // Insert missing METARs
        for remote_metar in remote_metars.clone() {
          remote_metar.insert().await?;
          found_metar_icaos.insert(remote_metar.icao.to_string());
          let mut metar_check = MetarCheck::new(remote_metar.icao.clone(), true).await;
          metar_check.last_metar = Some(remote_metar);
          metar_check.insert(time_offset as u64).await?;
        }
        metars.append(&mut remote_metars);
      }

      // Update still missing metars
      // let mut still_missing_metar_icaos: Vec<String> = vec![];
      for difference in found_metar_icaos.symmetric_difference(&requested_icaos) {
        // still_missing_metar_icaos.push(difference.to_string());
        let metar_check = MetarCheck::new(difference.to_string(), false).await;
        metar_check.insert(short_time_offset as u64).await?;
        // Only add cached metar data if it's less than 4 hours old
        if let Some(last_metar) = metar_check.last_metar {
          let four_hours_ago = Utc::now() - chrono::Duration::hours(4);
          if last_metar.observation_time < four_hours_ago {
            metars.push(last_metar);
          }
        }
      }
      // if !still_missing_metar_icaos.is_empty() {
      //   log::trace!("Still missing METAR data from {:?}", still_missing_metar_icaos);
      // }
    }

    Ok(metars)
  }

  pub async fn insert(&self) -> ApiResult<()> {
    log::trace!(
      "Inserting metar {} with observation time {}",
      self.icao,
      self.observation_time
    );
    let metar: MetarRow = self.to_db()?;
    metar.insert().await?;
    Ok(())
  }
}

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

  #[test]
  fn test_parse_time() {
    for day in 1..=31 {
      for hour in 0..24 {
        for minute in 0..60 {
          // METAR form "DDHHMMZ"
          let obs_time = format!("{:02}{:02}{:02}Z", day, hour, minute);
          let result = Metar::parse_time(&obs_time);
          match result {
            Ok(datetime_str) => {
              // "YYYY-MM-DDTHH:MM:00Z"
              assert_eq!(
                datetime_str.len(),
                20,
                "Unexpected length for input {} yielded {}",
                obs_time,
                datetime_str
              );
              // Remove the trailing 'Z' and parse
              let trimmed = &datetime_str[..19];
              NaiveDateTime::parse_from_str(trimmed, "%Y-%m-%dT%H:%M:%S").unwrap_or_else(|e| {
                panic!(
                  "Parsing '{}' from input {} failed: {}",
                  trimmed, obs_time, e
                )
              });
            }
            Err(_err) => {}
          }
        }
      }
    }
  }

  #[tokio::test]
  async fn test_metar() {
    let mut metar_string = "METAR KABC 121755Z AUTO 21016G24KT 180V240 1SM R11/P6000FT -RA BR BKN015 OVC025 06/04 A2990
RMK AO2 PK WND 20032/25 WSHFT 1715 VIS 3/4V1 1/2 VIS 3/4 RWY11 RAB07 CIG 013V017 CIG 017 RWY11 PRESFR
SLP125 P0003 60009 T00640036 10066 21012 58033 TSNO $".to_string();
    let metar = Metar::parse(&metar_string).unwrap();
    dbg!(&metar.observation_time);

    metar_string = "KMIA 090053Z 33004KT 10SM FEW015 FEW024 SCT075 SCT250 25/22 A2990 RMK AO2 SLP126 T02500217 $".to_string();
    let metar = Metar::parse(&metar_string).unwrap();
    dbg!(&metar.observation_time);

    metar_string =
      "KMRB 082253Z 30014G23KT 10SM CLR 05/M12 A3002 RMK AO2 PK WND 30028/2157 SLP168 T00501117"
        .to_string();
    let metar = Metar::parse(&metar_string).unwrap();
    dbg!(&metar.observation_time);

    metar_string = "KHEF 092356Z 13009KT 10SM CLR 08/M03 A3022 RMK AO2 SLP239 6//// T00831033 10133 20078 53002 PNO $".to_string();
    let metar = Metar::parse(&metar_string).unwrap();
    dbg!(&metar.observation_time);

    metar_string = "KSLK 162351Z AUTO VRB03KT 1SM -SN BR FEW007 OVC014 00/M02 A2974 RMK AO2 SLP090 P0001 60004 T00001017 10000 21011 53026".to_string();
    let metar = Metar::parse(&metar_string).unwrap();
    dbg!(&metar.observation_time);
  }
}