use std::{ops::RangeInclusive, sync::Arc};

use anyhow::bail;
use client::{Client, ZED_SECRET_CLIENT_TOKEN, ZED_SERVER_URL};
use db::kvp::KEY_VALUE_STORE;
use editor::{Editor, EditorEvent};
use futures::AsyncReadExt;
use gpui::{
    div, rems, serde_json, AppContext, DismissEvent, Div, EventEmitter, FocusHandle, FocusableView,
    Model, PromptLevel, Render, Task, View, ViewContext,
};
use isahc::Request;
use language::Buffer;
use project::Project;
use regex::Regex;
use serde_derive::Serialize;
use ui::{prelude::*, Button, ButtonStyle, IconPosition, Label, Tooltip};
use util::ResultExt;
use workspace::Workspace;

use crate::{system_specs::SystemSpecs, GiveFeedback, OpenZedCommunityRepo};

const DATABASE_KEY_NAME: &str = "email_address";
const EMAIL_REGEX: &str = r"\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b";
const FEEDBACK_CHAR_LIMIT: RangeInclusive<usize> = 10..=5000;
const FEEDBACK_SUBMISSION_ERROR_TEXT: &str =
    "Feedback failed to submit, see error log for details.";

#[derive(Serialize)]
struct FeedbackRequestBody<'a> {
    feedback_text: &'a str,
    email: Option<String>,
    metrics_id: Option<Arc<str>>,
    installation_id: Option<Arc<str>>,
    system_specs: SystemSpecs,
    is_staff: bool,
    token: &'a str,
}

pub struct FeedbackModal {
    system_specs: SystemSpecs,
    feedback_editor: View<Editor>,
    email_address_editor: View<Editor>,
    character_count: usize,
    pending_submission: bool,
}

impl FocusableView for FeedbackModal {
    fn focus_handle(&self, cx: &AppContext) -> FocusHandle {
        self.feedback_editor.focus_handle(cx)
    }
}
impl EventEmitter<DismissEvent> for FeedbackModal {}

impl FeedbackModal {
    pub fn register(workspace: &mut Workspace, cx: &mut ViewContext<Workspace>) {
        let _handle = cx.view().downgrade();
        workspace.register_action(move |workspace, _: &GiveFeedback, cx| {
            let markdown = workspace
                .app_state()
                .languages
                .language_for_name("Markdown");

            let project = workspace.project().clone();

            cx.spawn(|workspace, mut cx| async move {
                let markdown = markdown.await.log_err();
                let buffer = project
                    .update(&mut cx, |project, cx| {
                        project.create_buffer("", markdown, cx)
                    })?
                    .expect("creating buffers on a local workspace always succeeds");

                workspace.update(&mut cx, |workspace, cx| {
                    let system_specs = SystemSpecs::new(cx);

                    workspace.toggle_modal(cx, move |cx| {
                        FeedbackModal::new(system_specs, project, buffer, cx)
                    });
                })?;

                anyhow::Ok(())
            })
            .detach_and_log_err(cx);
        });
    }

    pub fn new(
        system_specs: SystemSpecs,
        project: Model<Project>,
        buffer: Model<Buffer>,
        cx: &mut ViewContext<Self>,
    ) -> Self {
        let email_address_editor = cx.build_view(|cx| {
            let mut editor = Editor::single_line(cx);
            editor.set_placeholder_text("Email address (optional)", cx);

            if let Ok(Some(email_address)) = KEY_VALUE_STORE.read_kvp(DATABASE_KEY_NAME) {
                editor.set_text(email_address, cx)
            }

            editor
        });

        let feedback_editor = cx.build_view(|cx| {
            let mut editor = Editor::for_buffer(buffer, Some(project.clone()), cx);
            editor.set_placeholder_text(
                "You can use markdown to add links or organize feedback.",
                cx,
            );
            // editor.set_show_gutter(false, cx);
            editor.set_vertical_scroll_margin(5, cx);
            editor
        });

        cx.subscribe(
            &feedback_editor,
            |this, editor, event: &EditorEvent, cx| match event {
                EditorEvent::Edited => {
                    this.character_count = editor
                        .read(cx)
                        .buffer()
                        .read(cx)
                        .as_singleton()
                        .expect("Feedback editor is never a multi-buffer")
                        .read(cx)
                        .len();
                    cx.notify();
                }
                _ => {}
            },
        )
        .detach();

        Self {
            system_specs: system_specs.clone(),
            feedback_editor,
            email_address_editor,
            pending_submission: false,
            character_count: 0,
        }
    }

    pub fn submit(&mut self, cx: &mut ViewContext<Self>) -> Task<anyhow::Result<()>> {
        let feedback_text = self.feedback_editor.read(cx).text(cx).trim().to_string();
        let email = self.email_address_editor.read(cx).text_option(cx);

        let answer = cx.prompt(
            PromptLevel::Info,
            "Ready to submit your feedback?",
            &["Yes, Submit!", "No"],
        );
        let client = cx.global::<Arc<Client>>().clone();
        let specs = self.system_specs.clone();
        cx.spawn(|this, mut cx| async move {
            let answer = answer.await.ok();
            if answer == Some(0) {
                match email.clone() {
                    Some(email) => {
                        let _ = KEY_VALUE_STORE
                            .write_kvp(DATABASE_KEY_NAME.to_string(), email)
                            .await;
                    }
                    None => {
                        let _ = KEY_VALUE_STORE
                            .delete_kvp(DATABASE_KEY_NAME.to_string())
                            .await;
                    }
                };

                this.update(&mut cx, |feedback_editor, cx| {
                    feedback_editor.set_pending_submission(true, cx);
                })
                .log_err();

                if let Err(error) =
                    FeedbackModal::submit_feedback(&feedback_text, email, client, specs).await
                {
                    log::error!("{}", error);
                    this.update(&mut cx, |feedback_editor, cx| {
                        let prompt = cx.prompt(
                            PromptLevel::Critical,
                            FEEDBACK_SUBMISSION_ERROR_TEXT,
                            &["OK"],
                        );
                        cx.spawn(|_, _cx| async move {
                            prompt.await.ok();
                        })
                        .detach();
                        feedback_editor.set_pending_submission(false, cx);
                    })
                    .log_err();
                }
            }
        })
        .detach();
        Task::ready(Ok(()))
    }

    fn set_pending_submission(&mut self, pending_submission: bool, cx: &mut ViewContext<Self>) {
        self.pending_submission = pending_submission;
        cx.notify();
    }

    async fn submit_feedback(
        feedback_text: &str,
        email: Option<String>,
        zed_client: Arc<Client>,
        system_specs: SystemSpecs,
    ) -> anyhow::Result<()> {
        let feedback_endpoint = format!("{}/api/feedback", *ZED_SERVER_URL);
        let telemetry = zed_client.telemetry();
        let metrics_id = telemetry.metrics_id();
        let installation_id = telemetry.installation_id();
        let is_staff = telemetry.is_staff();
        let http_client = zed_client.http_client();
        let request = FeedbackRequestBody {
            feedback_text: &feedback_text,
            email,
            metrics_id,
            installation_id,
            system_specs,
            is_staff: is_staff.unwrap_or(false),
            token: ZED_SECRET_CLIENT_TOKEN,
        };
        let json_bytes = serde_json::to_vec(&request)?;
        let request = Request::post(feedback_endpoint)
            .header("content-type", "application/json")
            .body(json_bytes.into())?;
        let mut response = http_client.send(request).await?;
        let mut body = String::new();
        response.body_mut().read_to_string(&mut body).await?;
        let response_status = response.status();
        if !response_status.is_success() {
            bail!("Feedback API failed with error: {}", response_status)
        }
        Ok(())
    }

    // TODO: Escape button calls dismiss
    // TODO: Should do same as hitting cancel / clicking outside of modal
    //     Close immediately if no text in field
    //     Ask to close if text in the field
    fn cancel(&mut self, _: &menu::Cancel, cx: &mut ViewContext<Self>) {
        cx.emit(DismissEvent);
    }
}

impl Render for FeedbackModal {
    type Element = Div;

    fn render(&mut self, cx: &mut ViewContext<Self>) -> Self::Element {
        let valid_email_address = match self.email_address_editor.read(cx).text_option(cx) {
            Some(email_address) => Regex::new(EMAIL_REGEX).unwrap().is_match(&email_address),
            None => true,
        };

        let valid_character_count = FEEDBACK_CHAR_LIMIT.contains(&self.character_count);
        let characters_remaining =
            if valid_character_count || self.character_count > *FEEDBACK_CHAR_LIMIT.end() {
                *FEEDBACK_CHAR_LIMIT.end() as i32 - self.character_count as i32
            } else {
                self.character_count as i32 - *FEEDBACK_CHAR_LIMIT.start() as i32
            };

        let allow_submission =
            valid_character_count && valid_email_address && !self.pending_submission;

        let has_feedback = self.feedback_editor.read(cx).text_option(cx).is_some();

        let submit_button_text = if self.pending_submission {
            "Sending..."
        } else {
            "Send Feedback"
        };
        let dismiss = cx.listener(|_, _, cx| {
            cx.emit(DismissEvent);
        });
        // TODO: get the "are you sure you want to dismiss?" prompt here working
        let dismiss_prompt = cx.listener(|_, _, _| {
            // let answer = cx.prompt(PromptLevel::Info, "Exit feedback?", &["Yes", "No"]);
            // cx.spawn(|_, _| async move {
            //     let answer = answer.await.ok();
            //     if answer == Some(0) {
            //         cx.emit(DismissEvent);
            //     }
            // })
            // .detach();
        });
        let open_community_repo =
            cx.listener(|_, _, cx| cx.dispatch_action(Box::new(OpenZedCommunityRepo)));

        v_stack()
            .elevation_3(cx)
            .key_context("GiveFeedback")
            .on_action(cx.listener(Self::cancel))
            .min_w(rems(40.))
            .max_w(rems(96.))
            .h(rems(32.))
            .p_4()
            .gap_4()
            .child(
                v_stack()
                    .child(
                        // TODO: Add Headline component to `ui2`
                        div().text_xl().child("Share Feedback"))
            )
            .child(
                    div()
                        .flex_1()
                        .bg(cx.theme().colors().editor_background)
                        .p_2()
                        .border()
                        .rounded_md()
                        .border_color(cx.theme().colors().border)
                        .child(self.feedback_editor.clone()),
                )
                .child(
                    div().child(
                        Label::new(
                            if !valid_character_count && characters_remaining < 0 {
                                "Feedback must be at least 10 characters.".to_string()
                            } else if !valid_character_count && characters_remaining > 5000 {
                                "Feedback must be less than 5000 characters.".to_string()
                            } else {
                                format!(
                                "Characters: {}",
                                characters_remaining
                                )
                            }
                        )
                        .map(|this|
                            if valid_character_count {
                                this.color(Color::Success)
                            } else {
                                this.color(Color::Error)
                            }
                        )
                    )

                        .child(
                    h_stack()
                    .bg(cx.theme().colors().editor_background)
                    .p_2()
                    .border()
                    .rounded_md()
                    .border_color(cx.theme().colors().border)
                    .child(self.email_address_editor.clone()))

                .child(
                    h_stack()
                        .justify_between()
                        .gap_1()
                        .child(Button::new("community_repo", "Community Repo")
                            .style(ButtonStyle::Transparent)
                            .icon(Icon::ExternalLink)
                            .icon_position(IconPosition::End)
                            .icon_size(IconSize::Small)
                            .on_click(open_community_repo)
                        )
                        .child(h_stack().gap_1()
                            .child(
                                Button::new("cancel_feedback", "Cancel")
                                    .style(ButtonStyle::Subtle)
                                    .color(Color::Muted)
                                    // TODO: replicate this logic when clicking outside the modal
                                    // TODO: Will require somehow overriding the modal dismal default behavior
                                    .map(|this| {
                                        if has_feedback {
                                            this.on_click(dismiss_prompt)
                                        } else {
                                            this.on_click(dismiss)
                                        }
                                    })
                            )
                            .child(
                                Button::new("send_feedback", submit_button_text)
                                    .color(Color::Accent)
                                    .style(ButtonStyle::Filled)
                                    // TODO: Ensure that while submitting, "Sending..." is shown and disable the button
                                    // TODO: If submit errors: show popup with error, don't close modal, set text back to "Send Feedback", and re-enable button
                                    // TODO: If submit is successful, close the modal
                                    .on_click(cx.listener(|this, _, cx| {
                                        let _ = this.submit(cx);
                                    }))
                                    .tooltip(|cx| {
                                        Tooltip::with_meta(
                                            "Submit feedback to the Zed team.",
                                            None,
                                            "Provide an email address if you want us to be able to reply.",
                                            cx,
                                        )
                                    })
                                    .when(!allow_submission, |this| this.disabled(true))
                            ),
                        )

                )
            )
    }
}

// TODO: Add compilation flags to enable debug mode, where we can simulate sending feedback that both succeeds and fails, so we can test the UI