use crate::ast::{SchemaJsonError, serde_string_or_struct::*};
use crate::{BNode, IriOrStr, ShapeExprLabel};
use iri_s::error::IriSError;
use iri_s::{IriS, iri};
use prefixmap::error::PrefixMapError;
use prefixmap::{IriRef, PrefixMap};
use serde::{Deserialize, Serialize};
use std::fmt::Display;
use std::path::{Path, PathBuf};
use std::{fs, io};
use tracing::{debug, trace};

use super::{SemAct, ShapeDecl, ShapeExpr};

#[derive(Deserialize, Serialize, Debug, PartialEq, Clone)]
pub struct Schema {
    #[serde(rename = "@context")]
    context: String,

    #[serde(rename = "type")]
    type_: String,

    #[serde(skip_serializing_if = "Option::is_none")]
    imports: Option<Vec<IriOrStr>>,

    #[serde(
        default,
        skip_serializing_if = "Option::is_none",
        serialize_with = "serialize_opt_string_or_struct",
        deserialize_with = "deserialize_opt_string_or_struct"
    )]
    start: Option<ShapeExpr>,

    #[serde(default, rename = "startActs", skip_serializing_if = "Option::is_none")]
    start_acts: Option<Vec<SemAct>>,

    #[serde(skip_serializing_if = "Option::is_none")]
    shapes: Option<Vec<ShapeDecl>>,

    #[serde(skip_serializing_if = "Option::is_none")]
    prefixmap: Option<PrefixMap>,

    #[serde(skip_serializing_if = "Option::is_none")]
    base: Option<IriS>,

    /// Source IRI from which this Schema has been obtained
    #[serde(skip)]
    source_iri: IriS,
}

impl Schema {
    pub fn new(source_iri: &IriS) -> Schema {
        Schema {
            context: "http://www.w3.org/ns/shex.jsonld".to_string(),
            type_: "Schema".to_string(),
            imports: None,
            start: None,
            start_acts: None,
            shapes: None,
            prefixmap: None,
            base: None,
            source_iri: source_iri.clone(),
        }
    }

    pub fn imports(&self) -> Option<Vec<IriOrStr>> {
        self.imports.clone()
    }

    /// Returns the list of imports declared in the Schema
    pub fn imports_resolved(&self, base: &Option<IriS>) -> Result<Vec<IriS>, IriSError> {
        if let Some(imports) = &self.imports {
            let rs: Result<Vec<IriS>, IriSError> =
                imports.iter().map(|i| i.resolve(base)).collect::<Result<Vec<_>, _>>();
            let is = rs?;
            Ok(is)
        } else {
            let is: Vec<IriS> = Vec::new();
            Ok(is)
        }
    }

    pub fn source_iri(&self) -> IriS {
        self.source_iri.clone()
    }

    pub fn with_source_iri(&mut self, source_iri: &IriS) {
        self.source_iri = source_iri.clone();
    }

    /// Obtain a Schema from an IRI
    pub fn from_iri(iri: &IriS) -> Result<Schema, SchemaJsonError> {
        let body = iri
            .dereference(Some(iri))
            .map_err(|e| SchemaJsonError::DereferencingIri {
                iri: iri.clone(),
                error: e,
            })?;
        let mut schema = Schema::from_reader(body.as_bytes())?;
        schema.with_source_iri(iri);
        Ok(schema)
    }

    pub fn with_import(mut self, i: IriRef) -> Self {
        let iri = IriOrStr::IriRef(i);
        match self.imports {
            None => self.imports = Some(vec![iri]),
            Some(ref mut imports) => imports.push(iri),
        }
        self
    }

    pub fn with_start_actions(mut self, start_actions: Option<Vec<SemAct>>) -> Self {
        self.start_acts = start_actions;
        self
    }

    pub fn add_prefix(&mut self, alias: &str, iri: &IriS) -> Result<(), PrefixMapError> {
        match self.prefixmap {
            None => {
                let mut pm = PrefixMap::new();
                pm.add_prefix(alias, iri.clone())?;
                self.prefixmap = Some(pm);
            },
            Some(ref mut pm) => pm.add_prefix(alias, iri.clone())?,
        };
        Ok(())
    }

    pub fn with_prefixmap(mut self, prefixmap: Option<PrefixMap>) -> Self {
        self.prefixmap = prefixmap;
        self
    }

    pub fn with_base(mut self, base: Option<IriS>) -> Self {
        self.base = base;
        self
    }

    pub fn with_start(mut self, start: Option<ShapeExpr>) -> Self {
        self.start = start;
        self
    }

    pub fn with_shapes(mut self, shapes: Option<Vec<ShapeDecl>>) -> Self {
        self.shapes = shapes;
        self
    }

    pub fn resolve_iriref(&self, iri_ref: &IriRef) -> IriS {
        match &self.prefixmap {
            Some(pm) => match pm.resolve_iriref(iri_ref.clone()) {
                Err(_) => todo!(),
                Ok(iri) => iri.clone(),
            },
            None => match iri_ref {
                IriRef::Iri(iri) => iri.clone(),
                IriRef::Prefixed { prefix, local } => {
                    let str = format!("{prefix}{local}");
                    IriS::new_unchecked(str.as_str())
                },
            },
        }
    }

    pub fn add_shape(&mut self, shape_label: ShapeExprLabel, shape_expr: ShapeExpr, is_abstract: bool) {
        let sd: ShapeDecl = ShapeDecl::new(shape_label, shape_expr, is_abstract);
        match self.shapes {
            None => {
                self.shapes = Some(vec![sd]);
            },
            Some(ref mut ses) => ses.push(sd),
        }
    }

    pub fn add_shape_decl(&mut self, shape_decl: &ShapeDecl) {
        match self.shapes {
            None => self.shapes = Some(vec![shape_decl.clone()]),
            Some(ref mut ses) => ses.push(shape_decl.clone()),
        }
    }

    pub fn parse_schema(path: &Path) -> Result<Schema, SchemaJsonError> {
        trace!("Parsing SchemaJson from path: {}", path.display());
        let schema = {
            let schema_str = fs::read_to_string(path).map_err(|e| SchemaJsonError::ReadingPathError {
                path_name: path.display().to_string(),
                error: e.to_string(),
            })?;
            trace!("SchemaJson read from {}: {}", path.display(), schema_str);
            serde_json::from_str::<Schema>(&schema_str).map_err(|e| SchemaJsonError::JsonError {
                path_name: path.display().to_string(),
                error: e.to_string(),
            })?
        };
        debug!("SchemaJson parsed: {:?}", schema);
        Ok(schema)
    }

    pub fn from_reader<R: io::Read>(mut rdr: R) -> Result<Schema, SchemaJsonError> {
        let mut schema_str = String::new();
        rdr.read_to_string(&mut schema_str)
            .map_err(|e| SchemaJsonError::JsonErrorFromReader { error: e.to_string() })?;

        let schema = serde_json::from_str::<Schema>(&schema_str)
            .map_err(|e| SchemaJsonError::JsonErrorFromReader { error: e.to_string() })?;
        Ok(schema)
    }

    pub fn parse_schema_name(schema_name: &String, folder: &Path) -> Result<Schema, SchemaJsonError> {
        let json_path = Path::new(&schema_name);
        let mut attempt = PathBuf::from(folder);
        attempt.push(json_path);
        Self::parse_schema(&attempt)
    }

    pub fn base(&self) -> Option<IriS> {
        self.base.clone()
    }

    pub fn prefixmap(&self) -> Option<PrefixMap> {
        self.prefixmap.clone()
    }

    pub fn start_actions(&self) -> Option<Vec<SemAct>> {
        self.start_acts.clone()
    }

    pub fn start(&self) -> Option<ShapeExpr> {
        self.start.clone()
    }

    pub fn shapes(&self) -> Option<Vec<ShapeDecl>> {
        self.shapes.clone()
    }

    pub fn get_type(&self) -> String {
        self.type_.clone()
    }

    pub fn find_shape(&self, label: &str) -> Result<Option<ShapeExpr>, SchemaJsonError> {
        let label: ShapeExprLabel = if label == "START" {
            ShapeExprLabel::Start
        } else if let Some(bnode_label) = label.strip_prefix("_:") {
            ShapeExprLabel::BNode {
                value: BNode::new(bnode_label),
            }
        } else {
            ShapeExprLabel::IriRef {
                value: IriRef::try_from(label).map_err(|e| SchemaJsonError::InvalidIriRef {
                    label: label.to_string(),
                    error: e.to_string(),
                })?,
            }
        };
        match label {
            ShapeExprLabel::IriRef { value } => self.find_shape_by_iri_ref(&value),
            ShapeExprLabel::BNode { value: _ } => todo!(),
            ShapeExprLabel::Start => todo!(),
        }
    }

    pub fn find_shape_by_label(&self, label: &ShapeExprLabel) -> Result<Option<ShapeExpr>, SchemaJsonError> {
        match label {
            ShapeExprLabel::IriRef { value } => self.find_shape_by_iri_ref(value),
            ShapeExprLabel::BNode { value: _ } => todo!(),
            ShapeExprLabel::Start => todo!(),
        }
    }

    pub fn find_shape_by_iri_ref(&self, shape: &IriRef) -> Result<Option<ShapeExpr>, SchemaJsonError> {
        let prefixmap = match &self.prefixmap {
            None => PrefixMap::default(),
            Some(pm) => {
                // TODO: This should not be necessary
                pm.clone()
            },
        };
        if let Some(shapes) = self.shapes() {
            let expected_iri = prefixmap.resolve_iriref(shape.clone())?;
            for shape_decl in shapes {
                if let ShapeExprLabel::IriRef { value } = shape_decl.id {
                    let iri = prefixmap.resolve_iriref(value.clone())?;
                    if iri == expected_iri {
                        return Ok(Some(shape_decl.shape_expr));
                    }
                }
            }
            // Not found in shapes
            Ok(None)
        } else {
            // No shapes
            Ok(None)
        }
    }
}

impl Default for Schema {
    fn default() -> Self {
        Self::new(&iri!("http://default/"))
    }
}

impl Display for Schema {
    // TODO: Improve
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "{}",
            serde_json::to_string_pretty(&self).map_err(|_| std::fmt::Error)?
        )
    }
}

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

    #[test]
    fn test_deser_user() {
        let str = r#"
        {
            "type": "Schema",
            "shapes": [
              {
                "type": "ShapeDecl",
                "id": "http://example.org/User",
                "shapeExpr": {
                  "type": "Shape",
                  "expression": {
                        "type": "TripleConstraint",
                        "predicate": "http://schema.org/name",
                        "valueExpr": {
                          "type": "NodeConstraint",
                          "datatype": "http://www.w3.org/2001/XMLSchema#string",
                          "length": 3
                        }
                  }
                }
              }
            ],
            "@context": "http://www.w3.org/ns/shex.jsonld"
          }
        "#;

        let schema: Schema = serde_json::from_str(str).unwrap();
        let serialized = serde_json::to_string_pretty(&schema).unwrap();
        let schema_after_serialization = serde_json::from_str(&serialized).unwrap();
        assert_eq!(schema, schema_after_serialization);
    }

    #[test]
    fn test_deser_nplus1() {
        let str = r#"
        {
  "@context": "http://www.w3.org/ns/shex.jsonld",
  "type": "Schema",
  "shapes": [
    {
      "type": "ShapeDecl",
      "id": "http://a.example.org/S",
      "shapeExpr": {
      "type": "Shape",
      "expression": {
        "type": "EachOf",
        "expressions": [
          {
            "type": "TripleConstraint",
            "predicate": "http://a.example/a",
            "min": 0,
            "max": -1
          },
          {
            "type": "TripleConstraint",
            "predicate": "http://a.example/a"
          }
        ]
      }
    }
    }
  ]
}
        "#;

        let schema: Schema = serde_json::from_str(str).unwrap();
        let serialized = serde_json::to_string_pretty(&schema).unwrap();
        let schema_after_serialization = serde_json::from_str(&serialized).unwrap();
        assert_eq!(schema, schema_after_serialization);
    }
}
