use thiserror::Error;

/// Represents errors that can occur during email operations.
///
/// These errors typically occur during email template rendering,
/// email confirmation token generation/verification, and SMTP sending.
#[derive(Debug, Error)]
pub enum EmailError {
    /// Error when the HMAC secret key is invalid.
    ///
    /// This error occurs when attempting to create an HMAC instance with
    /// an invalid key format or length.
    #[error("error-smokesignal-email-1 Invalid HMAC key: {0}")]
    InvalidHmacKey(String),

    /// Error when the confirmation token format is invalid.
    ///
    /// This error occurs when attempting to parse a confirmation token
    /// that doesn't match the expected format (token.time_bucket.signature).
    #[error("error-smokesignal-email-2 Invalid confirmation token format")]
    InvalidTokenFormat,

    /// Error when the time bucket in a confirmation token cannot be parsed.
    ///
    /// This error occurs when the time bucket component of a confirmation
    /// token is not a valid integer.
    #[error("error-smokesignal-email-3 Invalid time bucket in confirmation token")]
    InvalidTimeBucket,

    /// Error when the confirmation token signature is invalid or expired.
    ///
    /// This error occurs when the HMAC signature of a confirmation token
    /// doesn't match the expected value, or the token has expired (older
    /// than the previous 10-minute time bucket).
    #[error("error-smokesignal-email-4 Invalid or expired confirmation token signature")]
    InvalidOrExpiredSignature,

    /// Error when a template file contains invalid UTF-8.
    ///
    /// This error occurs when loading an email template file that contains
    /// invalid UTF-8 byte sequences.
    #[error("error-smokesignal-email-5 Invalid UTF-8 in template {template}: {details}")]
    InvalidUtf8InTemplate {
        /// The name of the template file.
        template: String,
        /// Details about the UTF-8 error.
        details: String,
    },

    /// Error when adding a template to the template engine fails.
    ///
    /// This error occurs when the template engine rejects a template,
    /// typically due to syntax errors or invalid template directives.
    #[error("error-smokesignal-email-6 Failed to add template {template}: {details}")]
    TemplateAddFailed {
        /// The name of the template file.
        template: String,
        /// Details about why adding the template failed.
        details: String,
    },

    /// Error when retrieving a text template fails.
    ///
    /// This error occurs when attempting to get a template that doesn't
    /// exist or cannot be loaded from the template engine.
    #[error("error-smokesignal-email-7 Failed to get text template {template}: {details}")]
    TextTemplateGetFailed {
        /// The path to the template.
        template: String,
        /// Details about the retrieval failure.
        details: String,
    },

    /// Error when rendering a text template fails.
    ///
    /// This error occurs when template rendering fails, typically due to
    /// missing variables or invalid template syntax.
    #[error("error-smokesignal-email-8 Failed to render text template {template}: {details}")]
    TextTemplateRenderFailed {
        /// The path to the template.
        template: String,
        /// Details about the rendering failure.
        details: String,
    },

    /// Error when retrieving an HTML template fails.
    ///
    /// This error occurs when attempting to get an HTML template that doesn't
    /// exist or cannot be loaded from the template engine.
    #[error("error-smokesignal-email-9 Failed to get HTML template {template}: {details}")]
    HtmlTemplateGetFailed {
        /// The path to the template.
        template: String,
        /// Details about the retrieval failure.
        details: String,
    },

    /// Error when rendering an HTML template fails.
    ///
    /// This error occurs when HTML template rendering fails, typically due to
    /// missing variables or invalid template syntax.
    #[error("error-smokesignal-email-10 Failed to render HTML template {template}: {details}")]
    HtmlTemplateRenderFailed {
        /// The path to the template.
        template: String,
        /// Details about the rendering failure.
        details: String,
    },

    /// Error when CSS inlining fails.
    ///
    /// This error occurs when the CSS inlining process fails, typically
    /// due to invalid CSS syntax or malformed HTML.
    #[error("error-smokesignal-email-11 Failed to inline CSS in template {template}: {details}")]
    CssInlineFailed {
        /// The path to the template.
        template: String,
        /// Details about the CSS inlining failure.
        details: String,
    },

    /// Error when HTML minification fails.
    ///
    /// This error occurs when the HTML minification process fails,
    /// typically due to malformed HTML structure.
    #[error("error-smokesignal-email-12 Failed to minify HTML in template {template}: {details}")]
    HtmlMinifyFailed {
        /// The path to the template.
        template: String,
        /// Details about the minification failure.
        details: String,
    },

    /// Error when parsing SMTP credentials fails.
    ///
    /// This error occurs when the SMTP username cannot be parsed into
    /// valid SMTP credentials format.
    #[error("error-smokesignal-email-13 Failed to parse SMTP credentials: {0}")]
    SmtpCredentialsParseFailed(String),

    /// Error when the "from" email address is invalid.
    ///
    /// This error occurs when the SMTP_FROM address cannot be parsed
    /// as a valid email address.
    #[error("error-smokesignal-email-14 Invalid from email address: {0}")]
    InvalidFromAddress(String),

    /// Error when a recipient email address is invalid.
    ///
    /// This error occurs when a recipient's email address cannot be parsed
    /// as a valid email address.
    #[error("error-smokesignal-email-15 Invalid recipient email address {address}: {details}")]
    InvalidRecipientAddress {
        /// The invalid email address.
        address: String,
        /// Details about why the address is invalid.
        details: String,
    },

    /// Error when building an email message fails.
    ///
    /// This error occurs when the email builder fails to construct a valid
    /// email message, typically due to missing required fields.
    #[error("error-smokesignal-email-16 Failed to build email message: {0}")]
    EmailBuildFailed(String),

    /// Error when sending an email fails.
    ///
    /// This error occurs when the SMTP transport fails to send the email,
    /// typically due to network issues or SMTP server errors.
    #[error("error-smokesignal-email-17 Failed to send email: {0}")]
    EmailSendFailed(String),

    /// Error when an attachment content type is invalid.
    ///
    /// This error occurs when parsing a content type string for an email
    /// attachment fails.
    #[error("error-smokesignal-email-18 Invalid attachment content type {content_type}: {details}")]
    InvalidAttachmentContentType {
        /// The invalid content type string.
        content_type: String,
        /// Details about the parsing failure.
        details: String,
    },
}