//! Modal for request_user_input tool prompts.

use crossterm::event::{KeyCode, KeyEvent};
use ratatui::layout::{Alignment, Rect};
use ratatui::prelude::*;
use ratatui::widgets::{Block, Borders, Clear, Padding, Paragraph, Widget, Wrap};

use crate::palette;
use crate::tools::user_input::{
    UserInputAnswer, UserInputQuestion, UserInputRequest, UserInputResponse,
};
use crate::tui::views::{ModalKind, ModalView, ViewAction, ViewEvent};

fn modal_block(title: &str) -> Block<'static> {
    Block::default()
        .title(Line::from(vec![Span::styled(
            title.to_string(),
            Style::default().fg(palette::DEEPSEEK_BLUE).bold(),
        )]))
        .borders(Borders::ALL)
        .border_style(Style::default().fg(palette::BORDER_COLOR))
        .style(Style::default().bg(palette::DEEPSEEK_INK))
        .padding(Padding::uniform(1))
}

fn render_modal_chrome(area: Rect, popup_area: Rect, buf: &mut Buffer) {
    let shadow_x = popup_area.x.saturating_add(1);
    let shadow_y = popup_area.y.saturating_add(1);
    let shadow_right = area.x.saturating_add(area.width);
    let shadow_bottom = area.y.saturating_add(area.height);
    let shadow_width = popup_area.width.min(shadow_right.saturating_sub(shadow_x));
    let shadow_height = popup_area
        .height
        .min(shadow_bottom.saturating_sub(shadow_y));

    if shadow_width > 0 && shadow_height > 0 {
        Block::default()
            .style(Style::default().bg(palette::DEEPSEEK_NAVY))
            .render(
                Rect {
                    x: shadow_x,
                    y: shadow_y,
                    width: shadow_width,
                    height: shadow_height,
                },
                buf,
            );
    }

    Clear.render(popup_area, buf);
}

fn push_option_lines(
    lines: &mut Vec<Line<'static>>,
    selected: bool,
    number: usize,
    label: String,
    description: String,
) {
    let row_style = if selected {
        Style::default()
            .fg(palette::SELECTION_TEXT)
            .bg(palette::SELECTION_BG)
            .bold()
    } else {
        Style::default().fg(palette::TEXT_PRIMARY)
    };
    let detail_style = if selected {
        row_style
    } else {
        Style::default().fg(palette::TEXT_MUTED)
    };
    let prefix = if selected { ">" } else { " " };

    lines.push(Line::from(Span::styled(
        format!("{prefix} {number}) {label}"),
        row_style,
    )));
    lines.push(Line::from(Span::styled(
        format!("    {description}"),
        detail_style,
    )));
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum InputMode {
    Selecting,
    OtherInput,
}

#[derive(Debug, Clone)]
pub struct UserInputView {
    tool_id: String,
    request: UserInputRequest,
    question_index: usize,
    selected: usize,
    mode: InputMode,
    other_input: String,
    answers: Vec<UserInputAnswer>,
}

impl UserInputView {
    pub fn new(tool_id: impl Into<String>, request: UserInputRequest) -> Self {
        Self {
            tool_id: tool_id.into(),
            request,
            question_index: 0,
            selected: 0,
            mode: InputMode::Selecting,
            other_input: String::new(),
            answers: Vec::new(),
        }
    }

    fn current_question(&self) -> &UserInputQuestion {
        &self.request.questions[self.question_index]
    }

    fn option_count(&self) -> usize {
        self.current_question().options.len() + 1
    }

    fn is_other_selected(&self) -> bool {
        self.selected + 1 == self.option_count()
    }

    fn advance_question(&mut self, answer: UserInputAnswer) -> ViewAction {
        self.answers.push(answer);
        if self.question_index + 1 >= self.request.questions.len() {
            let response = UserInputResponse {
                answers: self.answers.clone(),
            };
            return ViewAction::EmitAndClose(ViewEvent::UserInputSubmitted {
                tool_id: self.tool_id.clone(),
                response,
            });
        }
        self.question_index += 1;
        self.selected = 0;
        self.mode = InputMode::Selecting;
        self.other_input.clear();
        ViewAction::None
    }

    fn handle_selecting_key(&mut self, key: KeyEvent) -> ViewAction {
        match key.code {
            KeyCode::Up | KeyCode::Char('k') => {
                self.selected = self.selected.saturating_sub(1);
                ViewAction::None
            }
            KeyCode::Down | KeyCode::Char('j') => {
                self.selected = (self.selected + 1).min(self.option_count().saturating_sub(1));
                ViewAction::None
            }
            KeyCode::Char(ch) if ch.is_ascii_digit() => {
                let Some(number) = ch.to_digit(10) else {
                    return ViewAction::None;
                };
                if number == 0 {
                    return ViewAction::None;
                }
                let index = usize::try_from(number - 1).unwrap_or(usize::MAX);
                if index >= self.option_count() {
                    return ViewAction::None;
                }
                self.selected = index;
                if self.is_other_selected() {
                    self.mode = InputMode::OtherInput;
                    self.other_input.clear();
                    ViewAction::None
                } else {
                    let question = self.current_question();
                    let option = &question.options[self.selected];
                    let answer = UserInputAnswer {
                        id: question.id.clone(),
                        label: option.label.clone(),
                        value: option.label.clone(),
                    };
                    self.advance_question(answer)
                }
            }
            KeyCode::Enter => {
                if self.is_other_selected() {
                    self.mode = InputMode::OtherInput;
                    self.other_input.clear();
                    ViewAction::None
                } else {
                    let question = self.current_question();
                    let option = &question.options[self.selected];
                    let answer = UserInputAnswer {
                        id: question.id.clone(),
                        label: option.label.clone(),
                        value: option.label.clone(),
                    };
                    self.advance_question(answer)
                }
            }
            KeyCode::Esc => ViewAction::EmitAndClose(ViewEvent::UserInputCancelled {
                tool_id: self.tool_id.clone(),
            }),
            _ => ViewAction::None,
        }
    }

    fn handle_other_input_key(&mut self, key: KeyEvent) -> ViewAction {
        match key.code {
            KeyCode::Esc => {
                self.mode = InputMode::Selecting;
                self.other_input.clear();
                ViewAction::None
            }
            KeyCode::Enter => {
                let question = self.current_question();
                let answer = UserInputAnswer {
                    id: question.id.clone(),
                    label: "Other".to_string(),
                    value: self.other_input.trim().to_string(),
                };
                self.advance_question(answer)
            }
            KeyCode::Backspace => {
                self.other_input.pop();
                ViewAction::None
            }
            KeyCode::Char(ch) => {
                if !ch.is_control() {
                    self.other_input.push(ch);
                }
                ViewAction::None
            }
            _ => ViewAction::None,
        }
    }
}

impl ModalView for UserInputView {
    fn kind(&self) -> ModalKind {
        ModalKind::UserInput
    }

    fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
        self
    }

    fn handle_key(&mut self, key: KeyEvent) -> ViewAction {
        match self.mode {
            InputMode::Selecting => self.handle_selecting_key(key),
            InputMode::OtherInput => self.handle_other_input_key(key),
        }
    }

    fn render(&self, area: Rect, buf: &mut Buffer) {
        let question = self.current_question();
        let total = self.request.questions.len();
        let header = format!(
            " {} ({}/{}) ",
            question.header,
            self.question_index + 1,
            total
        );

        let mut lines: Vec<Line> = Vec::new();
        lines.push(Line::from(vec![Span::styled(
            "Action required",
            Style::default().fg(palette::DEEPSEEK_SKY).bold(),
        )]));
        lines.push(Line::from(vec![
            Span::styled(
                question.header.clone(),
                Style::default().fg(palette::TEXT_PRIMARY).bold(),
            ),
            Span::styled(
                format!("  Question {} of {}", self.question_index + 1, total),
                Style::default().fg(palette::TEXT_MUTED),
            ),
        ]));
        lines.push(Line::from(""));
        lines.push(Line::from(vec![Span::styled(
            question.question.clone(),
            Style::default().fg(palette::TEXT_PRIMARY).bold(),
        )]));
        lines.push(Line::from(""));

        for (idx, option) in question.options.iter().enumerate() {
            let number = idx + 1;
            push_option_lines(
                &mut lines,
                self.selected == idx,
                number,
                option.label.clone(),
                option.description.clone(),
            );
        }

        let other_index = question.options.len();
        let other_number = other_index + 1;
        push_option_lines(
            &mut lines,
            self.selected == other_index,
            other_number,
            "Other".to_string(),
            "Type a custom response".to_string(),
        );

        if self.mode == InputMode::OtherInput {
            lines.push(Line::from(""));
            lines.push(Line::from(vec![
                Span::styled(
                    "> Custom response:",
                    Style::default().fg(palette::TEXT_PRIMARY).bold(),
                ),
                Span::raw(" "),
                Span::styled(
                    if self.other_input.is_empty() {
                        "(type your response)".to_string()
                    } else {
                        self.other_input.clone()
                    },
                    Style::default().fg(palette::DEEPSEEK_BLUE),
                ),
            ]));
        }

        lines.push(Line::from(""));
        if self.mode == InputMode::OtherInput {
            lines.push(Line::from(vec![
                Span::styled("Enter", Style::default().fg(palette::DEEPSEEK_SKY).bold()),
                Span::styled(" submit", Style::default().fg(palette::TEXT_MUTED)),
                Span::raw("  "),
                Span::styled("Esc", Style::default().fg(palette::DEEPSEEK_SKY).bold()),
                Span::styled(" back", Style::default().fg(palette::TEXT_MUTED)),
            ]));
        } else {
            lines.push(Line::from(vec![
                Span::styled("1-4", Style::default().fg(palette::DEEPSEEK_SKY).bold()),
                Span::styled(" quick pick", Style::default().fg(palette::TEXT_MUTED)),
                Span::raw("  "),
                Span::styled("Up/Down", Style::default().fg(palette::DEEPSEEK_SKY).bold()),
                Span::styled(" move", Style::default().fg(palette::TEXT_MUTED)),
                Span::raw("  "),
                Span::styled("Enter", Style::default().fg(palette::DEEPSEEK_SKY).bold()),
                Span::styled(" confirm", Style::default().fg(palette::TEXT_MUTED)),
                Span::raw("  "),
                Span::styled("Esc", Style::default().fg(palette::DEEPSEEK_SKY).bold()),
                Span::styled(" cancel", Style::default().fg(palette::TEXT_MUTED)),
            ]));
        }

        let paragraph = Paragraph::new(lines)
            .alignment(Alignment::Left)
            .wrap(Wrap { trim: true })
            .block(modal_block(&header));

        let popup_area = centered_rect(82, 68, area);
        render_modal_chrome(area, popup_area, buf);
        paragraph.render(popup_area, buf);
    }
}

fn centered_rect(percent_x: u16, percent_y: u16, r: Rect) -> Rect {
    let popup_layout = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Percentage((100 - percent_y) / 2),
            Constraint::Percentage(percent_y),
            Constraint::Percentage((100 - percent_y) / 2),
        ])
        .split(r);
    let horizontal = Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Percentage((100 - percent_x) / 2),
            Constraint::Percentage(percent_x),
            Constraint::Percentage((100 - percent_x) / 2),
        ])
        .split(popup_layout[1]);
    horizontal[1]
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::tools::user_input::{UserInputOption, UserInputQuestion, UserInputRequest};

    fn render_view(view: &UserInputView, width: u16, height: u16) -> String {
        let area = Rect::new(0, 0, width, height);
        let mut buf = Buffer::empty(area);
        view.render(area, &mut buf);

        (0..height)
            .map(|y| (0..width).map(|x| buf[(x, y)].symbol()).collect::<String>())
            .collect::<Vec<_>>()
            .join("\n")
    }

    fn sample_view() -> UserInputView {
        UserInputView::new(
            "tool-1",
            UserInputRequest {
                questions: vec![UserInputQuestion {
                    header: "Confirm".to_string(),
                    id: "confirm".to_string(),
                    question: "What should happen next?".to_string(),
                    options: vec![
                        UserInputOption {
                            label: "Ship it".to_string(),
                            description: "Proceed with the current change set".to_string(),
                        },
                        UserInputOption {
                            label: "Revise it".to_string(),
                            description: "Return to editing before continuing".to_string(),
                        },
                    ],
                }],
            },
        )
    }

    #[test]
    fn user_input_modal_calls_out_required_action_and_controls() {
        let rendered = render_view(&sample_view(), 110, 36);

        assert!(rendered.contains("Action required"));
        assert!(rendered.contains("Question 1 of 1"));
        assert!(rendered.contains("1-4"));
        assert!(rendered.contains("quick pick"));
    }

    #[test]
    fn user_input_modal_renders_custom_response_state() {
        let mut view = sample_view();
        view.selected = 2;
        view.mode = InputMode::OtherInput;
        view.other_input = "Need one more pass".to_string();

        let rendered = render_view(&view, 110, 36);

        assert!(rendered.contains("Custom response"));
        assert!(rendered.contains("Need one more pass"));
        assert!(rendered.contains("Enter"));
        assert!(rendered.contains("submit"));
    }
}
