use std::{
    collections::HashMap,
    fmt::{Display, Formatter},
};

use secrecy::ExposeSecret;
use serde::Deserialize;
use terrors::OneOf;

use crate::filesystem::FileSystem;

/// Mapped from the `git-next-server.toml` file
#[derive(Debug, PartialEq, Eq, Deserialize)]
pub struct ServerConfig {
    webhook: Webhook,
    forge: HashMap<String, Forge>,
}
impl ServerConfig {
    pub(crate) fn load(fs: &FileSystem) -> Result<Self, OneOf<(std::io::Error, toml::de::Error)>> {
        let str = fs.read_file("git-next-server.toml").map_err(OneOf::new)?;
        toml::from_str(&str).map_err(OneOf::new)
    }

    pub(crate) fn forges(&self) -> impl Iterator<Item = (ForgeName, &Forge)> {
        self.forge
            .iter()
            .map(|(name, forge)| (ForgeName(name.clone()), forge))
    }
}

/// Defines the Webhook Forges should send updates to
#[derive(Debug, PartialEq, Eq, Deserialize)]
pub struct Webhook {
    url: String,
}
impl Webhook {
    #[allow(dead_code)] // TODO: (#15) register webhook
    pub fn url(&self) -> WebhookUrl {
        WebhookUrl(self.url.clone())
    }
}

/// The URL for the webhook where forges should send their updates
pub struct WebhookUrl(String);
impl AsRef<str> for WebhookUrl {
    fn as_ref(&self) -> &str {
        &self.0
    }
}

/// Mapped from `.git-next.toml` file in target repo
/// Is also derived from the optional parameters in `git-next-server.toml` at
/// `forge.{forge}.repos.{repo}.(main|next|dev)`
#[derive(Clone, Debug, PartialEq, Eq, Deserialize)]
pub struct RepoConfig {
    branches: RepoBranches,
}
impl RepoConfig {
    #[allow(dead_code)]
    pub(crate) fn load(toml: &str) -> Result<Self, OneOf<(toml::de::Error,)>> {
        toml::from_str(toml).map_err(OneOf::new)
    }

    pub(crate) const fn branches(&self) -> &RepoBranches {
        &self.branches
    }
}
impl Display for RepoConfig {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{:?}", self.branches)
    }
}

/// Mapped from `.git-next.toml` file at `branches`
#[derive(Clone, Debug, PartialEq, Eq, Deserialize)]
pub struct RepoBranches {
    main: String,
    next: String,
    dev: String,
}
impl RepoBranches {
    pub fn main(&self) -> BranchName {
        BranchName(self.main.clone())
    }

    pub fn next(&self) -> BranchName {
        BranchName(self.next.clone())
    }

    pub fn dev(&self) -> BranchName {
        BranchName(self.dev.clone())
    }
}
impl Display for RepoBranches {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{:?}", self)
    }
}

/// Defines a Forge to connect to
/// Maps from `git-next-server.toml` at `forge.{forge}`
#[derive(Clone, Debug, PartialEq, Eq, Deserialize)]
pub struct Forge {
    forge_type: ForgeType,
    hostname: String,
    user: String,
    token: String,
    // API Token
    // Private SSH Key Path
    repos: HashMap<String, Repo>,
}
impl Forge {
    #[allow(dead_code)]
    pub const fn forge_type(&self) -> &ForgeType {
        &self.forge_type
    }

    pub fn hostname(&self) -> Hostname {
        Hostname(self.hostname.clone())
    }

    pub fn user(&self) -> User {
        User(self.user.clone())
    }

    pub fn token(&self) -> ApiToken {
        ApiToken(self.token.clone().into())
    }

    pub fn repos(&self) -> impl Iterator<Item = (RepoAlias, &Repo)> {
        self.repos
            .iter()
            .map(|(name, repo)| (RepoAlias(name.clone()), repo))
    }
}
impl Display for Forge {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{} - {}@{}", self.forge_type, self.user, self.hostname)
    }
}

/// Defines a Repo within a Forge to be monitored by the server
/// Maps from `git-next-server.toml` at `forge.{forge}.repos.{name}`
#[derive(Clone, Debug, PartialEq, Eq, Deserialize)]
pub struct Repo {
    repo: String,
    branch: String,
    main: Option<String>,
    next: Option<String>,
    dev: Option<String>,
}
impl Repo {
    #[allow(dead_code)]
    pub fn repo(&self) -> RepoPath {
        RepoPath(self.repo.clone())
    }

    #[allow(dead_code)]
    pub fn branch(&self) -> BranchName {
        BranchName(self.branch.clone())
    }
    /// Returns a RepoConfig from the server configuration if ALL THREE branches were provided
    pub fn repo_config(&self) -> Option<RepoConfig> {
        match (&self.main, &self.next, &self.dev) {
            (Some(main), Some(next), Some(dev)) => Some(RepoConfig {
                branches: RepoBranches {
                    main: main.to_string(),
                    next: next.to_string(),
                    dev: dev.to_string(),
                },
            }),
            _ => None,
        }
    }
}
#[cfg(test)]
impl AsRef<Self> for Repo {
    fn as_ref(&self) -> &Self {
        self
    }
}
impl Display for Repo {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{} - {}", self.repo, self.branch)
    }
}

/// The name of a Forge to connect to
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct ForgeName(pub String);
impl Display for ForgeName {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

/// The hostname of a forge
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Hostname(pub String);
impl Display for Hostname {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

/// The user within the forge to connect as
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct User(pub String);
impl Display for User {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

/// The API Token for the [user]
/// ForgeJo: https://{hostname}/user/settings/applications
/// Github:  https://github.com/settings/tokens
#[derive(Clone, Debug)]
pub struct ApiToken(pub secrecy::Secret<String>);
impl From<String> for ApiToken {
    fn from(value: String) -> Self {
        Self(value.into())
    }
}
/// The API Token is in effect a password, so it must be explicitly exposed to access its value
impl ExposeSecret<String> for ApiToken {
    fn expose_secret(&self) -> &String {
        self.0.expose_secret()
    }
}

/// The derived information about a Forge, used to create interactions with it
#[derive(Clone, Debug)]
pub struct ForgeDetails {
    pub name: ForgeName,
    pub forge_type: ForgeType,
    pub hostname: Hostname,
    pub user: User,
    pub token: ApiToken,
    // API Token
    // Private SSH Key Path
}
impl From<(&ForgeName, &Forge)> for ForgeDetails {
    fn from(forge: (&ForgeName, &Forge)) -> Self {
        Self {
            name: forge.0.clone(),
            forge_type: forge.1.forge_type.clone(),
            hostname: forge.1.hostname(),
            user: forge.1.user(),
            token: forge.1.token(),
        }
    }
}

/// The alias of a repo
/// This is the alias for the repo within `git-next-server.toml`
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct RepoAlias(pub String);
impl Display for RepoAlias {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

/// The path for the repo within the forge.
/// Typically this is composed of the user or organisation and the name of the repo
/// e.g. `{user}/{repo}`
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct RepoPath(pub String);
impl Display for RepoPath {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

/// The name of a Branch
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub struct BranchName(pub String);
impl Display for BranchName {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

/// The derived information about a repo, used to interact with it
#[derive(Clone, Debug)]
pub struct RepoDetails {
    pub name: RepoAlias,
    pub repo: RepoPath,
    pub branch: BranchName,
    pub forge: ForgeDetails,
    pub config: Option<RepoConfig>,
}
impl RepoDetails {
    pub fn new(name: &RepoAlias, repo: &Repo, forge_name: &ForgeName, forge: &Forge) -> Self {
        Self {
            name: name.clone(),
            repo: RepoPath(repo.repo.clone()),
            config: repo.repo_config(),
            branch: BranchName(repo.branch.clone()),
            forge: ForgeDetails {
                name: forge_name.clone(),
                forge_type: forge.forge_type.clone(),
                hostname: forge.hostname(),
                user: forge.user(),
                token: forge.token(),
            },
        }
    }
}
impl Display for RepoDetails {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "{}/{} ({}): {}:{}/{} @ {}",
            self.forge.name,
            self.name,
            self.forge.forge_type,
            self.forge.hostname,
            self.forge.user,
            self.repo,
            self.branch,
        )
    }
}

/// Identifier for the type of Forge
#[derive(Clone, Debug, PartialEq, Eq, Deserialize)]
pub enum ForgeType {
    #[cfg(feature = "forgejo")]
    ForgeJo,
    // Gitea,
    // GitHub,
    // GitLab,
    // BitBucket,
    #[cfg(test)]
    MockForge,
}
impl Display for ForgeType {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{:?}", self)
    }
}

#[cfg(feature = "forgejo")]
#[cfg(test)]
mod tests {

    use crate::filesystem::FileSystem;

    use super::*;

    #[test]
    #[cfg(feature = "forgejo")]
    fn test_server_config_load() -> Result<(), OneOf<(std::io::Error, toml::de::Error)>> {
        let fs = FileSystem::new_temp().map_err(OneOf::new)?;
        fs.write_file(
            "git-next-server.toml",
            r#"
            [webhook]
            url = "http://localhost:9909/webhook"

            [forge.default]
            forge_type = "ForgeJo"
            hostname = "git.example.net"
            user = "Bob"
            token = "API-Token"

            [forge.default.repos]
            hello = { repo = "user/hello", branch = "main" }
            world = { repo = "user/world", branch = "master", main = "main", next = "next", dev = "dev" }

            [forge.default.repos.sam]
            repo = "user/sam"
            branch = "main"
            main = "master"
            next = "upcoming"
            dev = "sam-dev"
        "#,
        )
        .map_err(OneOf::new)?;
        let config = ServerConfig::load(&fs)?;
        let expected = ServerConfig {
            webhook: Webhook {
                url: "http://localhost:9909/webhook".to_string(),
            },
            forge: HashMap::from([(
                "default".to_string(),
                Forge {
                    forge_type: ForgeType::ForgeJo,
                    hostname: "git.example.net".to_string(),
                    user: "Bob".to_string(),
                    token: "API-Token".to_string(),
                    repos: HashMap::from([
                        (
                            "hello".to_string(),
                            Repo {
                                repo: "user/hello".to_string(),
                                branch: "main".to_string(),
                                main: None,
                                next: None,
                                dev: None,
                            },
                        ),
                        (
                            "world".to_string(),
                            Repo {
                                repo: "user/world".to_string(),
                                branch: "master".to_string(),
                                main: Some("main".to_string()),
                                next: Some("next".to_string()),
                                dev: Some("dev".to_string()),
                            },
                        ),
                        (
                            "sam".to_string(),
                            Repo {
                                repo: "user/sam".to_string(),
                                branch: "main".to_string(),
                                main: Some("master".to_string()),
                                next: Some("upcoming".to_string()),
                                dev: Some("sam-dev".to_string()),
                            },
                        ),
                    ]),
                },
            )]),
        };
        assert_eq!(config, expected, "ServerConfig");

        if let Some(forge) = config.forge.get("world") {
            if let Some(repo) = forge.repos.get("sam") {
                let repo_config = repo.repo_config();
                let expected = Some(RepoConfig {
                    branches: RepoBranches {
                        main: "master".to_string(),
                        next: "upcoming".to_string(),
                        dev: "sam-dev".to_string(),
                    },
                });
                assert_eq!(repo_config, expected, "RepoConfig");
            }
        }

        Ok(())
    }

    #[test]
    fn test_repo_config_load() -> Result<(), OneOf<(toml::de::Error,)>> {
        let toml = r#"
            [branches]
            main = "main"
            next = "next"
            dev = "dev"

            [options]
        "#;
        let config = RepoConfig::load(toml)?;

        assert_eq!(
            config,
            RepoConfig {
                branches: RepoBranches {
                    main: "main".to_string(),
                    next: "next".to_string(),
                    dev: "dev".to_string(),
                },
            }
        );

        Ok(())
    }
}