//! Plugin manifest parsing and validation

use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::path::Path;
use thiserror::Error;

use crate::{Capabilities, EnvironmentCapability, FilesystemCapability, NetworkCapability};

/// Plugin manifest file format (TOML)
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PluginManifest {
    pub plugin: PluginInfo,

    #[serde(default)]
    pub capabilities: ManifestCapabilities,

    #[serde(default)]
    pub config: HashMap<String, toml::Value>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PluginInfo {
    pub name: String,
    pub version: String,
    pub api_version: String,
    pub author: Option<String>,
    pub description: Option<String>,
    pub homepage: Option<String>,
    pub license: Option<String>,

    /// Plugin kind(s) - e.g., ["media_type", "metadata_extractor"]
    pub kind: Vec<String>,

    /// Binary configuration
    pub binary: PluginBinary,

    /// Dependencies on other plugins
    #[serde(default)]
    pub dependencies: Vec<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PluginBinary {
    /// Path to WASM binary
    pub wasm: String,

    /// Optional entrypoint function name (default: "_start")
    pub entrypoint: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct ManifestCapabilities {
    #[serde(default)]
    pub filesystem: ManifestFilesystemCapability,

    #[serde(default)]
    pub network: bool,

    #[serde(default)]
    pub environment: Option<Vec<String>>,

    #[serde(default)]
    pub max_memory_mb: Option<usize>,

    #[serde(default)]
    pub max_cpu_time_secs: Option<u64>,
}

#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct ManifestFilesystemCapability {
    #[serde(default)]
    pub read: Vec<String>,

    #[serde(default)]
    pub write: Vec<String>,
}

#[derive(Debug, Error)]
pub enum ManifestError {
    #[error("Failed to read manifest file: {0}")]
    IoError(#[from] std::io::Error),

    #[error("Failed to parse manifest: {0}")]
    ParseError(#[from] toml::de::Error),

    #[error("Invalid manifest: {0}")]
    ValidationError(String),
}

impl PluginManifest {
    /// Load and parse a plugin manifest from a TOML file
    pub fn from_file(path: &Path) -> Result<Self, ManifestError> {
        let content = std::fs::read_to_string(path)?;
        let manifest: Self = toml::from_str(&content)?;
        manifest.validate()?;
        Ok(manifest)
    }

    /// Parse a manifest from TOML string
    pub fn parse_str(content: &str) -> Result<Self, ManifestError> {
        let manifest: Self = toml::from_str(content)?;
        manifest.validate()?;
        Ok(manifest)
    }

    /// Validate the manifest
    pub fn validate(&self) -> Result<(), ManifestError> {
        // Check API version format
        if self.plugin.api_version.is_empty() {
            return Err(ManifestError::ValidationError(
                "api_version cannot be empty".to_string(),
            ));
        }

        // Check version format (basic semver check)
        if !self.plugin.version.contains('.') {
            return Err(ManifestError::ValidationError(
                "version must be in semver format (e.g., 1.0.0)".to_string(),
            ));
        }

        // Check that at least one kind is specified
        if self.plugin.kind.is_empty() {
            return Err(ManifestError::ValidationError(
                "at least one plugin kind must be specified".to_string(),
            ));
        }

        // Check plugin kinds are valid
        let valid_kinds = [
            "media_type",
            "metadata_extractor",
            "thumbnail_generator",
            "search_backend",
            "event_handler",
            "theme_provider",
        ];

        for kind in &self.plugin.kind {
            if !valid_kinds.contains(&kind.as_str()) {
                return Err(ManifestError::ValidationError(format!(
                    "Invalid plugin kind: {}. Must be one of: {}",
                    kind,
                    valid_kinds.join(", ")
                )));
            }
        }

        // Check WASM binary path is not empty
        if self.plugin.binary.wasm.is_empty() {
            return Err(ManifestError::ValidationError(
                "WASM binary path cannot be empty".to_string(),
            ));
        }

        Ok(())
    }

    /// Convert manifest capabilities to API capabilities
    pub fn to_capabilities(&self) -> Capabilities {
        Capabilities {
            filesystem: FilesystemCapability {
                read: self
                    .capabilities
                    .filesystem
                    .read
                    .iter()
                    .map(|s| s.into())
                    .collect(),
                write: self
                    .capabilities
                    .filesystem
                    .write
                    .iter()
                    .map(|s| s.into())
                    .collect(),
            },
            network: NetworkCapability {
                enabled: self.capabilities.network,
                allowed_domains: None,
            },
            environment: EnvironmentCapability {
                enabled: self.capabilities.environment.is_some(),
                allowed_vars: self.capabilities.environment.clone(),
            },
            max_memory_bytes: self
                .capabilities
                .max_memory_mb
                .map(|mb| mb.saturating_mul(1024).saturating_mul(1024)),
            max_cpu_time_ms: self
                .capabilities
                .max_cpu_time_secs
                .map(|secs| secs.saturating_mul(1000)),
        }
    }

    /// Get plugin ID (derived from name and version)
    pub fn plugin_id(&self) -> String {
        format!("{}@{}", self.plugin.name, self.plugin.version)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_parse_valid_manifest() {
        let toml = r#"
[plugin]
name = "heif-support"
version = "1.0.0"
api_version = "1.0"
author = "Test Author"
description = "HEIF image support"
kind = ["media_type", "metadata_extractor"]

[plugin.binary]
wasm = "plugin.wasm"

[capabilities.filesystem]
read = ["/tmp/pinakes-thumbnails"]
"#;

        let manifest = PluginManifest::parse_str(toml).unwrap();
        assert_eq!(manifest.plugin.name, "heif-support");
        assert_eq!(manifest.plugin.version, "1.0.0");
        assert_eq!(manifest.plugin.kind.len(), 2);
    }

    #[test]
    fn test_invalid_api_version() {
        let toml = r#"
[plugin]
name = "test"
version = "1.0.0"
api_version = ""
kind = ["media_type"]

[plugin.binary]
wasm = "plugin.wasm"
"#;

        assert!(PluginManifest::parse_str(toml).is_err());
    }

    #[test]
    fn test_invalid_kind() {
        let toml = r#"
[plugin]
name = "test"
version = "1.0.0"
api_version = "1.0"
kind = ["invalid_kind"]

[plugin.binary]
wasm = "plugin.wasm"
"#;

        assert!(PluginManifest::parse_str(toml).is_err());
    }
}