use std::iter::zip;

use interim_models::presentation::{DropdownOption, Presentation, RFC_3339_S, TextInputMode};
use serde::Deserialize;

use crate::errors::AppError;

/// A subset of an HTTP form that represents a [`Presentation`] in its component
/// parts. It may be merged into a larger HTTP form using `serde(flatten)`.
#[derive(Clone, Debug, Deserialize)]
pub(crate) struct PresentationForm {
    pub(crate) presentation_tag: String,

    #[serde(default)]
    pub(crate) dropdown_option_colors: Vec<String>,

    #[serde(default)]
    pub(crate) dropdown_option_values: Vec<String>,

    #[serde(default)]
    pub(crate) text_input_mode: String,

    #[serde(default)]
    pub(crate) timestamp_format: String,
}

impl TryFrom<PresentationForm> for Presentation {
    type Error = AppError;

    fn try_from(form_value: PresentationForm) -> Result<Self, Self::Error> {
        // Parses the presentation tag into the correct enum variant, but without
        // meaningful inner value(s). Match arms should all use the
        // `MyVariant { .. }` pattern to pay attention to only the tag.
        let presentation_default = Presentation::try_from(form_value.presentation_tag.as_str())?;
        Ok(match presentation_default {
            Presentation::Dropdown { .. } => Presentation::Dropdown {
                allow_custom: false,
                options: zip(
                    form_value.dropdown_option_colors,
                    form_value.dropdown_option_values,
                )
                .map(|(color, value)| DropdownOption { color, value })
                .collect(),
            },
            Presentation::Text { .. } => Presentation::Text {
                input_mode: TextInputMode::try_from(form_value.text_input_mode.as_str())?,
            },
            Presentation::Timestamp { .. } => Presentation::Timestamp {
                format: if form_value.timestamp_format.is_empty() {
                    RFC_3339_S.to_owned()
                } else {
                    form_value.timestamp_format
                },
            },
            Presentation::Uuid { .. } => Presentation::Uuid {},
        })
    }
}