use std::{collections::HashMap, path::PathBuf};

use serde::{ser::SerializeStruct, Deserialize, Deserializer, Serialize};
use serde_json::Value;

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct Plan {
    plan: Vec<PlanElement>,
    current: usize,
    #[serde(flatten)]
    metadata: PlanMetadata,
}

#[derive(Deserialize, Debug, Clone)]
pub struct PlanMetadata {
    stored_path: Option<PathBuf>,
    update_url: Option<String>,
    latest_server_etag: Option<String>,
    identifier: Option<String>,
    #[serde(default)]
    #[serde(deserialize_with = "deserialize_option_string")]
    last_stored_time: Option<String>,
}

impl PlanMetadata {
    pub fn set_stored_path(&mut self, file: Option<PathBuf>) {
        self.stored_path = file;
    }
}

impl Serialize for PlanMetadata {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        let mut state = serializer.serialize_struct("PlanMetadata", 6)?;

        state.serialize_field("update_url", &self.update_url)?;
        state.serialize_field("stored_path", &self.stored_path)?;
        state.serialize_field("latest_server_etag", &self.latest_server_etag)?;
        state.serialize_field("identifier", &self.identifier)?;
        state.serialize_field("last_stored_time", &self.last_stored_time)?;

        if let Some(path) = &self.stored_path {
            if let Some(name) = path.file_name() {
                state.serialize_field("name", &name.to_str())?;
            }
        }

        state.end()
    }
}

// Custom deserializer that accepts both strings and legacy number for the stored_time field
fn deserialize_option_string<'de, D>(deserializer: D) -> Result<Option<String>, D::Error>
where
    D: Deserializer<'de>,
{
    let v: Option<Value> = Option::deserialize(deserializer)?;
    Ok(match v {
        Some(Value::String(s)) => Some(s),
        Some(Value::Number(n)) => Some(n.to_string()),
        _ => None,
    })
}

impl From<PlanMetadata> for Option<Plan> {
    fn from(metadata: PlanMetadata) -> Self {
        Some(serde_json::from_slice(&std::fs::read(metadata.stored_path?).ok()?).ok()?)
    }
}

impl Plan {
    pub fn set_stored_path(&mut self, file: Option<PathBuf>) {
        self.metadata.stored_path = file;
    }
}

#[derive(Debug, Deserialize, Serialize, Clone)]
pub struct PlanElement {
    area_key: String,
    notes: String,

    #[serde(default = "PlanElement::generate_uuid")]
    uuid: uuid::Uuid,

    #[serde(default = "PlanElement::edited")]
    edited: bool,

    anchor_act: Option<u8>,

    #[serde(default, skip_serializing_if = "is_false")]
    checkpoint: bool,
}

fn is_false(flag: &bool) -> bool {
    !flag
}

impl PlanElement {
    pub fn generate_uuid() -> uuid::Uuid {
        uuid::Uuid::new_v4()
    }

    pub fn edited() -> bool {
        false
    }
}

#[allow(dead_code)]
#[derive(Debug, Deserialize)]
struct OldPlanElement {
    area: OldArea,
    note: String,
}

#[allow(dead_code)]
#[derive(Debug, Deserialize)]
struct OldPlan {
    elements: Vec<OldPlanElement>,
    position: usize,
}

#[derive(Debug, Deserialize)]
struct OldArea {
    _rid: usize,
}

#[allow(dead_code)]
pub fn convert_old(path: PathBuf) -> Option<Plan> {
    let plan: OldPlan =
        serde_json::from_str(&std::fs::read_to_string(path).expect("Could not convert old"))
            .expect("could not convert old");

    let map = poe_data::world_area::load_world_areas_map(include_str!(
        "../../data/processed_world_areas.json"
    ));
    let map = map
        .iter()
        .map(|(k, v)| (v.key_id, k))
        .collect::<HashMap<usize, &String>>();

    Some(Plan {
        current: plan.position,
        plan: plan
            .elements
            .into_iter()
            .map(|plan_element| PlanElement {
                area_key: map[&plan_element.area._rid].to_owned(),
                notes: plan_element.note,
                uuid: PlanElement::generate_uuid(),
                edited: PlanElement::edited(),
                anchor_act: None,
                checkpoint: false,
            })
            .collect::<Vec<PlanElement>>(),
        metadata: PlanMetadata {
            stored_path: None,
            update_url: None,
            latest_server_etag: None,
            identifier: None,
            last_stored_time: None,
        },
    })
}