use graphql_client::reqwest::post_graphql;
use std::collections::HashMap;
use yew::prelude::*;

use crate::components;
use crate::graphql;

pub enum Msg {
    DoneFetchingCanVote {
        errors: Option<Vec<String>>,
        can_vote: bool,
    },
    DoneFetchingConfig {
        errors: Option<Vec<String>>,
        min: usize,
    },
    DoneFetchingTeachers {
        errors: Option<Vec<String>>,
        teachers: Vec<graphql::queries::teachers::teachers::TeachersTeachers>,
    },
    RadioSelect {
        priority: usize,
        teacher: i64,
    },
    Submit,
    Vote(Option<Vec<String>>),
    AddSlot,
    RemoveSlot,
    Reset,
}

#[derive(Properties, PartialEq)]
pub struct StudentVoteProps {
    pub token: String,
    pub onvoted: Callback<()>,
}

pub struct StudentVote {
    fetching: bool,
    can_vote: bool,
    errors: Option<Vec<String>>,
    min: usize,
    slots: usize,
    teachers: Vec<graphql::queries::teachers::teachers::TeachersTeachers>,
    votes: HashMap<usize, Option<i64>>,
}

impl Component for StudentVote {
    type Message = Msg;
    type Properties = StudentVoteProps;

    fn create(ctx: &Context<Self>) -> Self {
        let client = graphql::client(Some(&ctx.props().token)).unwrap();
        ctx.link().send_future(async move {
            let can_vote_response =
                post_graphql::<graphql::queries::students_can_vote::StudentsCanVote, _>(
                    &client,
                    graphql::URL.as_str(),
                    graphql::queries::students_can_vote::students_can_vote::Variables,
                )
                .await
                .unwrap();

            Msg::DoneFetchingCanVote {
                errors: components::graphql_errors::convert(can_vote_response.errors),
                can_vote: can_vote_response.data.unwrap().students_can_vote,
            }
        });

        Self {
            fetching: true,
            can_vote: false,
            errors: None,
            min: 0,
            slots: 0,
            teachers: vec![],
            votes: HashMap::new(),
        }
    }

    fn update(&mut self, ctx: &Context<Self>, msg: Self::Message) -> bool {
        match msg {
            Msg::DoneFetchingCanVote { errors, can_vote } => {
                self.errors = errors;
                self.can_vote = can_vote;

                if self.can_vote {
                    let client = graphql::client(Some(&ctx.props().token)).unwrap();
                    ctx.link().send_future(async move {
                        let response = post_graphql::<graphql::queries::config::Config, _>(
                            &client,
                            graphql::URL.as_str(),
                            graphql::queries::config::config::Variables,
                        )
                        .await
                        .unwrap();

                        Msg::DoneFetchingConfig {
                            errors: components::graphql_errors::convert(response.errors),
                            min: response
                                .data
                                .unwrap()
                                .config
                                .minimum_teacher_selection_count
                                as usize,
                        }
                    });
                } else {
                    self.fetching = false;
                }

                true
            }
            Msg::DoneFetchingConfig { errors, min } => {
                self.errors = errors;
                self.min = min;
                self.slots = self.min;

                let client = graphql::client(Some(&ctx.props().token)).unwrap();
                ctx.link().send_future(async move {
                    let response = post_graphql::<graphql::queries::teachers::Teachers, _>(
                        &client,
                        graphql::URL.as_str(),
                        graphql::queries::teachers::teachers::Variables,
                    )
                    .await
                    .unwrap();

                    Msg::DoneFetchingTeachers {
                        errors: components::graphql_errors::convert(response.errors),
                        teachers: response.data.unwrap().teachers,
                    }
                });

                true
            }
            Msg::DoneFetchingTeachers { errors, teachers } => {
                self.fetching = false;
                self.errors = errors;
                self.teachers = teachers;
                true
            }
            Msg::RadioSelect { priority, teacher } => {
                self.votes.insert(priority, Some(teacher));
                for (p, t) in self.votes.iter_mut() {
                    if *p > priority && *t == Some(teacher) {
                        *t = None;
                    }
                }

                true
            }
            Msg::Submit => {
                let client = graphql::client(Some(&ctx.props().token)).unwrap();
                let mut ids: Vec<(&usize, i64)> = self
                    .votes
                    .iter()
                    .filter_map(|(p, t)| t.map(|x| (p, x)))
                    .collect();
                ids.sort_by(|a, b| a.0.cmp(b.0));
                let teacher_ids: Vec<i64> = ids.into_iter().map(|(_, t)| t).collect();

                ctx.link().send_future(async move {
                    let response = post_graphql::<graphql::mutations::vote::Vote, _>(
                        &client,
                        graphql::URL.as_str(),
                        graphql::mutations::vote::vote::Variables { teacher_ids },
                    )
                    .await
                    .unwrap();
                    log::debug!("{:?}", response.data.unwrap().create_vote.unwrap());

                    Msg::Vote(components::graphql_errors::convert(response.errors))
                });

                false
            }
            Msg::Vote(errors) => {
                self.errors = errors;
                if self.errors.is_none() {
                    ctx.props().onvoted.emit(());
                    false
                } else {
                    true
                }
            }
            Msg::AddSlot => {
                if self.slots < self.teachers.len() {
                    self.slots += 1;
                    true
                } else {
                    false
                }
            }
            Msg::RemoveSlot => {
                if self.slots > self.min {
                    self.votes.remove(&(self.slots - 1));
                    self.slots -= 1;
                    true
                } else {
                    false
                }
            }
            Msg::Reset => {
                self.slots = self.min;
                true
            }
        }
    }

    fn view(&self, ctx: &Context<Self>) -> Html {
        if self.fetching {
            html! {
                <p>{ "Fetching..." }</p>
            }
        } else if !self.can_vote {
            html! {
                <p>{ "Noch nicht erlaubt zu wählen." }</p>
            }
        } else {
            let onsubmit = ctx.link().callback(|e: FocusEvent| {
                e.prevent_default();

                Msg::Submit
            });
            let mut teachers: Vec<i64> = vec![];

            html! {
                <>
                    <h3>{ "Wähle deine Wunschmentoren aus:" }</h3>
                    <form {onsubmit}>
                        { for (0..self.slots).map(|i| {
                            let curr_t = self.votes.get(&i);
                            if let Some(Some(t)) = curr_t {
                                teachers.push(*t);
                            }
                            let name = format!("mentors_{}", i);

                            html! {
                                <>
                                    <fieldset>
                                        <legend>{ format!("{}. Wahl", i + 1) }</legend>

                                        { for self.teachers.iter().enumerate().filter_map(|(j, t)| {
                                            let checked = curr_t == Some(&Some(t.id));

                                            if teachers.contains(&t.id) && !checked {
                                                None
                                            } else {
                                                let id = format!("{}_{}", name, j);
                                                let teacher_id = t.id;
                                                let onchange = ctx.link().callback(move |_| Msg::RadioSelect { priority: i, teacher: teacher_id });

                                                Some(html! {
                                                    <div>
                                                        <input
                                                            type="radio"
                                                            id={id.to_owned()}
                                                            name={name.to_owned()}
                                                            value={t.user.name.to_owned()}
                                                            required=true
                                                            {onchange}
                                                            {checked}
                                                        />
                                                        <label for={id}>{ &t.user.name }</label>
                                                    </div>
                                                })
                                            }
                                        }) }
                                    </fieldset>
                                    if i < self.slots - 1 {
                                        <br />
                                    }
                                </>
                            }
                        }) }

                        <div>
                            <button
                                onclick={ctx.link().callback(|e: MouseEvent| {
                                    e.prevent_default();
                                    Msg::AddSlot
                                })}
                            >
                                { "+" }
                            </button>
                            <button
                                onclick={ctx.link().callback(|e: MouseEvent| {
                                    e.prevent_default();
                                    Msg::RemoveSlot
                                })}
                            >
                                { "-" }
                            </button>
                        </div>

                        <div>
                            <input type="submit" value="Submit" />
                            <input type="reset" value="Reset" onclick={ctx.link().callback(|_| Msg::Reset)} />
                        </div>

                        <components::graphql_errors::GraphQLErrors errors={self.errors.clone()} />
                    </form>
                </>
            }
        }
    }
}