use crate::store::model::FieldKind;
use crate::store::{model, Indexes, Store};
use serde_json::Value;
use std::borrow::Cow;
use std::collections::BTreeSet;

use lazy_static::lazy_static;
use indexmap::map::IndexMap;
use rocket::request::{FormItems, FromForm};

lazy_static! {
    /// This is an example for using doc comment attributes
    static ref EMPTY_SET: BTreeSet<String> = Default::default();
}

#[derive(Serialize, Debug, Default)]
pub struct RenderedField<'a> {
    pub key: Cow<'a, str>,
    pub label: Cow<'a, str>,
    pub kind: &'static str,
    pub step: &'static str,
    pub min: String,
    pub max: String,
    pub all_tags_json: String,
    pub tags_json: String,
    pub options: Option<Vec<&'a String>>,
    pub value: Cow<'a, str>,
    pub checked: bool,
}

impl<'a> RenderedField<'a> {
    pub fn from_template_field<'i>(
        key: &'i String,
        field: &'i model::Field,
        value: Option<&'i Value>,
        index: &'i Indexes,
    ) -> RenderedField<'i> {
        let mut rendered = RenderedField::default();
        rendered.key = key.as_str().into();
        rendered.label = if field.label.is_empty() {
            titlecase::titlecase(&key.replace('_', " ")).into()
        } else {
            field.label.as_str().into()
        };

        match &field.kind {
            FieldKind::String => {
                rendered.kind = "string";
            }
            FieldKind::Text => {
                rendered.kind = "text";
            }
            FieldKind::Bool { default } => {
                rendered.kind = "bool";

                rendered.checked = if let Some(Value::Bool(v)) = value {
                    *v
                } else {
                    *default
                }
            }
            FieldKind::Int { min, max, default } => {
                rendered.kind = "number";

                let num = if let Some(Value::Number(n)) = value {
                    n.as_i64().expect("Error parsing number")
                } else {
                    *default
                };

                if let Some(n) = min {
                    rendered.min = n.to_string();
                }

                if let Some(n) = max {
                    rendered.max = n.to_string();
                }

                rendered.value = Cow::Owned(num.to_string());
                rendered.step = "1";
            }
            FieldKind::Float { min, max, default } => {
                rendered.kind = "number";

                let num = if let Some(Value::Number(n)) = value {
                    n.as_f64().expect("Error parsing number")
                } else {
                    *default
                };

                if let Some(n) = min {
                    rendered.min = n.to_string();
                }

                if let Some(n) = max {
                    rendered.max = n.to_string();
                }

                rendered.value = Cow::Owned(num.to_string());
                rendered.step = "any";
            }
            FieldKind::Enum { options, default } => {
                rendered.kind = "select";
                rendered.options = Some(options.iter().collect());

                if let Some(Value::String(s)) = value {
                    rendered.value = Cow::Borrowed(&s.as_str());
                } else if let Some(def) = default {
                    rendered.value = def.to_owned().into();
                }
            }
            FieldKind::FreeEnum { enum_group } => {
                rendered.kind = "free_select";
                let group = enum_group.as_ref().unwrap_or(key);
                let options = index.free_enums.get(group).unwrap_or(&EMPTY_SET);
                rendered.options = Some(options.iter().collect());
            }
            FieldKind::Tags { options } => {
                rendered.kind = "tags";
                rendered.options = Some(options.iter().collect());

                rendered.all_tags_json = serde_json::to_string(options).unwrap();
            }
            FieldKind::FreeTags { tag_group } => {
                rendered.kind = "free_tags";
                let group = tag_group.as_ref().unwrap_or(key);
                let options = index.free_tags.get(group).unwrap_or(&EMPTY_SET);

                rendered.options = Some(options.iter().collect());
                rendered.all_tags_json = "[]".into();
            }
        }

        // Shared code by multiple variants
        match field.kind {
            FieldKind::Text | FieldKind::String => {
                if let Some(Value::String(s)) = value {
                    rendered.value = Cow::Borrowed(&s.as_str());
                }
            }
            FieldKind::Enum { .. } | FieldKind::FreeEnum { .. } => {
                if let Some(Value::String(s)) = value {
                    rendered.value = Cow::Borrowed(&s.as_str());
                }
            }
            FieldKind::Tags { .. } | FieldKind::FreeTags { .. } => {
                if let Some(v) = value {
                    rendered.value = serde_json::from_value::<Vec<String>>(v.clone())
                        .unwrap()
                        .join(" ")
                        .into();
                    rendered.tags_json = serde_json::to_string(v).unwrap();
                } else {
                    rendered.tags_json = "[]".into();
                }
            }
            _ => {}
        }

        rendered
    }
}

#[derive(Serialize, Debug)]
pub struct RenderedCard<'a> {
    pub fields: Vec<RenderedField<'a>>,
    pub id: usize,
}

pub fn render_empty_fields(store: &Store) -> Vec<RenderedField> {
    let indexes = &store.index;

    store
        .model
        .fields
        .iter()
        .map(|(key, field)| RenderedField::from_template_field(key, field, None, indexes))
        .collect()
}

pub fn render_card_fields<'a>(
    store: &'a Store,
    values: &'a serde_json::Map<String, Value>,
) -> Vec<RenderedField<'a>> {
    let indexes = &store.index;

    store
        .model
        .fields
        .iter()
        .map(|(key, field)| {
            RenderedField::from_template_field(key, field, values.get(key), indexes)
        })
        .collect()
}


#[derive(Default)]
pub struct MapFromForm {
    pub data: IndexMap<String, String>,
}

impl<'a> FromForm<'a> for MapFromForm {
    type Error = ();

    fn from_form(items: &mut FormItems, _strict: bool) -> Result<Self, Self::Error> {
        let mut new = MapFromForm::default();
        items.for_each(|item| {
            let (k, v) = item.key_value_decoded();
            new.data.insert(k, v);
        });
        Ok(new)
    }
}

pub fn collect_card_form(store: &Store, mut form: MapFromForm) -> IndexMap<String, Value> {
    let mut card = IndexMap::new();

    for (k, field) in &store.model.fields {
        let mut value: Option<Value> = None;
        if let Some(input) = form.data.remove(k) {
            value = Some(match &field.kind {
                FieldKind::Text | FieldKind::String | FieldKind::FreeEnum { .. } => {
                    Value::String(input)
                }
                FieldKind::Bool { .. } => serde_json::to_value(true).unwrap(),
                FieldKind::Int { min, max, default } => {
                    let mut val: i64 = if input.is_empty() {
                        *default
                    } else {
                        input.parse().expect("Error parse number")
                    };

                    if let Some(min) = min {
                        val = val.max(*min);
                    }

                    if let Some(max) = max {
                        val = val.min(*max);
                    }

                    serde_json::to_value(val).unwrap()
                }
                FieldKind::Float { min, max, default } => {
                    let mut val: f64 = if input.is_empty() {
                        *default
                    } else {
                        input.parse().expect("Error parse number")
                    };

                    if let Some(min) = min {
                        val = val.min(*min);
                    }

                    if let Some(max) = max {
                        val = val.max(*max);
                    }

                    serde_json::to_value(val).unwrap()
                }
                FieldKind::Enum { options, default } => {
                    if options.contains(&input) {
                        Value::String(input)
                    } else {
                        let val = default.as_ref().map(ToOwned::to_owned).unwrap_or_else(|| {
                            options
                                .first()
                                .expect("fixed enum must have values")
                                .to_owned()
                        });

                        Value::String(val)
                    }
                }
                FieldKind::Tags { options } => {
                    let mut tags: Vec<String> = input
                        .split(' ')
                        .map(ToOwned::to_owned)
                        .filter_map(|tag| {
                            if options.contains(&tag) {
                                Some(tag)
                            } else {
                                None
                            }
                        })
                        .collect();

                    tags.sort();

                    serde_json::to_value(tags).unwrap()
                }
                FieldKind::FreeTags { .. } => {
                    let mut tags: Vec<String> = input
                        .split(' ')
                        .map(str::trim)
                        .filter(|s| !s.is_empty())
                        .map(ToOwned::to_owned)
                        .collect();

                    tags.sort();

                    serde_json::to_value(tags).unwrap()
                }
            });
        } else {
            if let FieldKind::Bool { .. } = field.kind {
                value = Some(Value::Bool(false));
            }
        }

        if let Some(v) = value {
            card.insert(k.to_owned(), v);
        }
    }

    card
}