use serde::{Deserialize, Serialize};

/// One page: a prompt plus the paths on from it. `id` doubles as the URL
/// path it's served at ("/" is the landing page). Loaded from a plain
/// YAML file per question in a content directory kept in its own git
/// repo (see ../portal-content) - editing content is a content-repo
/// commit, not a Rust rebuild.
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Question {
    pub id: String,
    #[serde(default)]
    pub route: Option<String>,
    pub name: String,
    #[serde(default)]
    pub description: String,
    /// Kanidm group required to view/submit this question - `None` means
    /// open to anyone, matching every question today. Content-driven
    /// on purpose: a gated page like "/review" is just a Question with
    /// this set, not a bespoke Rust route.
    #[serde(default)]
    pub qualifies: Option<String>,
    #[serde(default)]
    pub alternatives: Vec<Alternative>,
}

/// Whether `user` may view/submit `question`. `true` when the question
/// has no `qualifies` requirement. Mirrors `chat::is_authorized_for_room`
/// in cnats - same synchronous, I/O-free shape, same staleness tradeoff
/// (group membership is fixed at login, not re-checked live).
pub fn is_qualified(user: Option<&crate::auth::User>, question: &Question) -> bool {
    match &question.qualifies {
        None => true,
        Some(group) => user.is_some_and(|u| u.groups.iter().any(|g| g == group)),
    }
}

/// One path through a question: a short pitch, an optional next question
/// to advance to on submit, and the form (via `features`) that collects
/// what's needed to get there.
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Alternative {
    pub name: String,
    #[serde(default)]
    pub description: String,
    #[serde(default)]
    pub action: Option<String>,
    #[serde(default)]
    pub consequence: Vec<String>,
    #[serde(default)]
    pub encouragements: Vec<String>,
    #[serde(default)]
    pub features: Vec<Feature>,
    /// Names a NATS KV bucket to also durably store this submission
    /// into, beyond the ephemeral NATS event every submission already
    /// gets published as - just a bucket name, not a keyword the
    /// runtime special-cases (see `src/answers.rs`). Content-driven
    /// rather than matching on the alternative's name/copy, which would
    /// silently break if the wording changes later.
    #[serde(default)]
    pub record_as: Option<String>,
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Feature {
    pub name: String,
    #[serde(default)]
    pub description: String,
    #[serde(default)]
    pub requirements: Vec<Requirement>,
    /// Live data this feature pulls in. Read-only unless `transitions`
    /// is non-empty, in which case listed answers get one action button
    /// per transition (see `src/resource.rs`, `src/answers.rs`).
    #[serde(default)]
    pub resource: Option<ResourceSpec>,
}

/// Declares a NATS KV-backed live-data read. The bucket/key here are
/// only ever read server-side, from content the server itself loaded at
/// startup - `get_resource` (`src/resource.rs`) takes a question id +
/// feature name from the client, never a bucket/key directly, so a
/// visitor can never probe an arbitrary bucket by naming it. There is
/// no render-mode/"kind" tag here on purpose - what a resource displays
/// as follows from its data's own shape (a plain value, or a list of
/// `answers::Answer`s), not from a Rust-side special case per content
/// item.
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct ResourceSpec {
    pub bucket: String,
    /// A single item; omit to list the whole bucket.
    #[serde(default)]
    pub key: Option<String>,
    /// Kanidm group required to read this resource.
    #[serde(default)]
    pub requires_group: Option<String>,
    /// Must be explicitly set for an anonymous-readable resource - a
    /// spec with neither this nor `requires_group` is unreachable by
    /// design (fail closed, not fail open). Reads only - mutations
    /// (`transitions` below) always require `requires_group` regardless
    /// of this flag.
    #[serde(default)]
    pub public: bool,
    /// States a listed answer may move to, and the button label for
    /// each - empty means the resource is read-only. The allow-list a
    /// `transition_answer` call is checked against, so a client can
    /// never move an answer to a state content didn't declare.
    #[serde(default)]
    pub transitions: Vec<Transition>,
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Transition {
    pub to: String,
    pub label: String,
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Requirement {
    pub name: String,
    #[serde(default)]
    pub label: Option<String>,
    #[serde(default)]
    pub placeholder: Option<String>,
    #[serde(default = "default_requirement_type", rename = "type")]
    pub kind: String,
    #[serde(default)]
    pub optional: bool,
    /// `type: file` only - accept multiple files.
    #[serde(default)]
    pub multiple: bool,
    /// `type: file` only - HTML `accept` hint (UX only, not a security
    /// boundary - the upload handler re-checks content-type itself).
    #[serde(default)]
    pub accept: Option<String>,
}

fn default_requirement_type() -> String {
    "text".to_string()
}

impl Requirement {
    pub fn display_label(&self) -> String {
        self.label.clone().unwrap_or_else(|| self.name.clone())
    }
}

/// Fetches every `*.yaml` file under `subdir` in a Gitea repo as a
/// `Question`, keyed by its own `id`. `repo_url` is the repo's normal
/// browser URL (e.g. `https://project.uhhm.no/uhhm/questions`) - the
/// Gitea host, owner and repo name are all read from it. Runs once at
/// startup, over Gitea's public contents API (no auth - the content
/// repo is public); no hot-reload yet - restart the process (or add
/// polling later) to pick up content changes.
#[cfg(feature = "ssr")]
pub async fn load_questions_from_gitea(
    repo_url: &str,
    branch: &str,
    subdir: &str,
) -> anyhow::Result<std::collections::HashMap<String, Question>> {
    let parsed = url::Url::parse(repo_url)
        .map_err(|e| anyhow::anyhow!("parsing content repo url {repo_url}: {e}"))?;
    let api_base = format!(
        "{}://{}",
        parsed.scheme(),
        parsed
            .host_str()
            .ok_or_else(|| anyhow::anyhow!("no host in content repo url {repo_url}"))?
    );
    let mut segments = parsed
        .path_segments()
        .ok_or_else(|| anyhow::anyhow!("no path in content repo url {repo_url}"))?;
    let owner = segments
        .next()
        .filter(|s| !s.is_empty())
        .ok_or_else(|| anyhow::anyhow!("missing owner in content repo url {repo_url}"))?;
    let repo = segments
        .next()
        .filter(|s| !s.is_empty())
        .ok_or_else(|| anyhow::anyhow!("missing repo name in content repo url {repo_url}"))?;

    let client = openidconnect::reqwest::Client::new();
    let list_url = format!("{api_base}/api/v1/repos/{owner}/{repo}/contents/{subdir}?ref={branch}");
    let listing = client
        .get(&list_url)
        .send()
        .await
        .map_err(|e| anyhow::anyhow!("listing {list_url}: {e}"))?
        .error_for_status()
        .map_err(|e| anyhow::anyhow!("listing {list_url}: {e}"))?
        .text()
        .await
        .map_err(|e| anyhow::anyhow!("reading directory listing from {list_url}: {e}"))?;
    let entries: Vec<serde_json::Value> = serde_json::from_str(&listing)
        .map_err(|e| anyhow::anyhow!("parsing directory listing from {list_url}: {e}"))?;

    let mut out = std::collections::HashMap::new();
    for entry in entries {
        let name = entry.get("name").and_then(|v| v.as_str()).unwrap_or("");
        if !name.ends_with(".yaml") {
            continue;
        }
        let download_url = entry
            .get("download_url")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow::anyhow!("no download_url for {name}"))?;
        let raw = client
            .get(download_url)
            .send()
            .await
            .map_err(|e| anyhow::anyhow!("fetching {name}: {e}"))?
            .error_for_status()
            .map_err(|e| anyhow::anyhow!("fetching {name}: {e}"))?
            .text()
            .await
            .map_err(|e| anyhow::anyhow!("reading {name}: {e}"))?;
        let question: Question =
            serde_yaml::from_str(&raw).map_err(|e| anyhow::anyhow!("parsing {name}: {e}"))?;
        out.insert(question.id.clone(), question);
    }
    Ok(out)
}