#![allow(dead_code, unused_variables, clippy::upper_case_acronyms)]
use std::{collections::HashMap, str::FromStr};
use json::{JsonValue, object::Object};
//use curl::Curl;

#[derive(Clone, Debug, PartialEq)]
pub enum Direction {
    LTR, RTL, NULL
}

impl FromStr for Direction {
    type Err = JsonLdError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if s == "ltr" {
            Ok(Direction::LTR)
        } else if s == "rtl" {
            Ok(Direction::RTL)
        } else if s == "null" {
            Ok(Direction::NULL)
        } else {
            Err(JsonLdError::InvalidBaseDirection)
        }
    }
}

#[derive(Clone, Default, Debug, PartialEq)]
pub struct Context {
    remote_iri: String,
    base_iri: String,
    original_iri: String,
    // inverse context
    vocab: Option<String>,
    default_language: Option<String>,
    base_direction: Option<Direction>,
    previous_context: Option<Box<Context>>,
    terms: HashMap<String, Term>
}

#[derive(Clone, Default, Debug, PartialEq)]
pub struct Term {
    iri_mapping: String,
    prefix: bool,
    protected: bool,
    reverse: bool,
    base_iri: Option<String>,
    context: Option<Context>,
    container: Option<Vec<String>>,
    direction: Option<Direction>,
    index: Option<String>,
    language: Option<String>,
    nest: Option<String>,
    term_type: Option<String>
}

#[derive(Debug)]
pub enum JsonLdError {
    CollidingKeywords,
    ConflictingIndexes,
    ContextOverflow,
    CyclicIRIMapping,
    InvalidIdValue,
    InvalidImportValue,
    InvalidIncludedValue,
    InvalidIndexValue,
    InvalidNestValue,
    InvalidPrefixValue,
    InvalidPropagateValue,
    InvalidProtectedValue,
    InvalidReverseValue,
    InvalidVersionValue,
    InvalidBaseDirection,
    InvalidBaseIRI,
    InvalidContainerMapping,
    InvalidContextEntry,
    InvalidContextNullification,
    InvalidDefaultLanguage,
    InvalidIRIMapping,
    InvalidJSONLiteral,
    InvalidKeywordAlias,
    InvalidLanguageMapValue,
    InvalidLanguageMapping,
    InvalidLanguageTaggedString,
    InvalidLanguageTaggedValue,
    InvalidLocalContext,
    InvalidRemoteContext,
    InvalidReversePropertyMap,
    InvalidReversePropertyValue,
    InvalidReverseProperty,
    InvalidScopedContext,
    InvalidScriptElement,
    InvalidSetOrListObject,
    InvalidTermDefinition,
    InvalidTypeMapping,
    InvalidTypeValue,
    InvalidTypedValue,
    InvalidValueObjectValue,
    InvalidValueObject,
    InvalidVocabMapping,
    IRIConfusedWithPrefix,
    KeywordRedefinition,
    LoadingDocumentFailed,
    LoadingRemoteContextFailed,
    MultipleContextLinkHeaders,
    ProcessingModeConflict,
    ProtectedTermRedefinition
}

struct ContextOpts {
    override_protected: Option<bool>,
    propagate: Option<bool>,
    validate_scoped: Option<bool>
}

impl ContextOpts {
    fn new(override_protected: Option<bool>, propagate: Option<bool>, validate_scoped: Option<bool>) -> Self {
        Self { override_protected, propagate, validate_scoped }
    }
}

#[derive(Default)]
struct TermOpts {
    override_protected: Option<bool>,
    protected: Option<bool>,
    validate_scoped: Option<bool>
}

impl TermOpts {
    fn new(override_protected: Option<bool>, protected: Option<bool>, validate_scoped: Option<bool>) -> Self {
        Self { override_protected, protected, validate_scoped }
    }
}

pub impl From<JsonValue> for Context {
    
}

impl Context {
    fn parse_context(active_context: &mut Context, local_context: &JsonValue, base_url: &String,
                         remote_contexts: Option<Vec<Context>>, opts: ContextOpts) -> Result<Context, JsonLdError> {
        let mut result = active_context.clone();
        let remote_contexts = remote_contexts.unwrap_or(Vec::new());
        let override_protected = opts.override_protected.unwrap_or(false);
        let mut propagate = opts.propagate.unwrap_or(true);
        let validate_scoped = opts.validate_scoped.unwrap_or(true);
        let local_context = local_context.clone();

        let local_context = match local_context {
            JsonValue::Array(ctx) => ctx,
            JsonValue::Object(ref ctx) => {
                // TODO: can we move this later so we don't need to check for Object(_) twice?
                if let Some(prop) = ctx.get("@propagate") {
                    if let JsonValue::Boolean(prop) = prop {
                        propagate = *prop;
                    } else {
                        return Err(JsonLdError::InvalidPropagateValue);
                    }
                }
                vec![local_context]
            }
            _ => vec![local_context]
        };

        if !propagate && result.previous_context.is_none() {
            result.previous_context = Some(Box::new(active_context.clone()));
        }

        for context in local_context {
            let context = match &context {
                JsonValue::Null => {
                    if !override_protected {
                        for term in active_context.terms.values() {
                            if term.protected {
                                return Err(JsonLdError::InvalidContextNullification);
                            }
                        }
                    }
                    let old_result = result;
                    result = Context::default();
                    result.base_iri = base_url.clone();
                    result.original_iri = base_url.clone();
                    if !propagate {
                        result.previous_context = Some(Box::new(old_result));
                    }
                    continue;
                },
                JsonValue::String(value) => {
                    todo!()
                    // Remote context stuff
                },
                JsonValue::Object(definition) => definition,
                _ => { return Err(JsonLdError::InvalidLocalContext); }
            };

            let mut defined: HashMap<String, bool> = HashMap::new();

            if let Some(version) = context.get("@version") {
                if let JsonValue::String(version) = version {
                    if version != "1.1" {
                        return Err(JsonLdError::InvalidVersionValue);
                    }
                } else {
                    return Err(JsonLdError::InvalidVersionValue);
                }
            }

            if let Some(import) = context.get("@import") {
                if let JsonValue::String(import) = import {
                    todo!()
                } else {
                    return Err(JsonLdError::InvalidImportValue);
                }
            }

            if let Some(base) = context.get("@base") {
                if !remote_contexts.is_empty() {
                    match base {
                        JsonValue::Null => {
                            result.base_iri.clear();
                        }
                        JsonValue::String(base) => {
                            if base.contains("://") {
                                result.base_iri = base.to_string();
                            } else if base.contains(':') {
                                todo!();
                            } else {
                                return Err(JsonLdError::InvalidBaseIRI);
                            }
                        }
                        _ => return Err(JsonLdError::InvalidBaseIRI)
                    }
                }
            }

            if let Some(vocab) = context.get("@vocab") {
                match vocab {
                    JsonValue::Null => {
                        result.vocab = None;
                    },
                    JsonValue::String(vocab) => {
                        if vocab.contains("://") || vocab.starts_with("_:") {
                            Context::iri_expansion(active_context, vocab, &mut defined, Some(true), None, Some(context))?;
                        }
                    },
                    _ => return Err(JsonLdError::InvalidVocabMapping)
                }
            }

            if let Some(language) = context.get("@language") {
                match language {
                    JsonValue::Null => {
                        result.default_language = None;
                    },
                    JsonValue::String(language) => {
                        result.default_language = Some(language.to_string().to_lowercase());
                    },
                    _ => return Err(JsonLdError::InvalidDefaultLanguage)
                }
            }

            if let Some(direction) = context.get("@direction") {
                match direction {
                    JsonValue::Null => {
                        result.base_direction = None;
                    }
                    JsonValue::String(direction) => {
                        result.base_direction = Some(Direction::from_str(direction)?);
                    }
                    _ => return Err(JsonLdError::InvalidBaseDirection)
                }
            }

            if let Some(propagate) = context.get("@propagate") {
                if !propagate.is_boolean() {
                    return Err(JsonLdError::InvalidPropagateValue);
                }
            }

            let mut protected = false;
            if let Some(JsonValue::Boolean(prot)) = context.get("@protected") {
                protected = *prot;
            }

            for (key, term) in context.iter() {
                Context::create_term_definition(&mut result, context, (key, term), &mut defined, base_url,
                &remote_contexts, TermOpts::new(Some(protected), Some(override_protected), Some(validate_scoped)))?;
            }
        }

        Ok(result)
    }

    fn create_term_definition(active_context: &mut Context, local_context: &Object, term: (&str, &JsonValue),
                              defined: &mut HashMap<String, bool>, base_url: &String, remote_contexts: &Vec<Context>,
                              opts: TermOpts) -> Result<(), JsonLdError> {
        let protected = opts.protected.unwrap_or(false);
        let override_protected = opts.override_protected.unwrap_or(false);
        let validate_scoped = opts.validate_scoped.unwrap_or(true);
        let (key, term) = term;

        if key.starts_with('@') {
            return Err(JsonLdError::KeywordRedefinition);
        }

        if let Some(defined) = defined.get(key) {
            if *defined {
                return Ok(());
            } else {
                return Err(JsonLdError::CyclicIRIMapping);
            }
        }

        if key.is_empty() {
            return Err(JsonLdError::InvalidTermDefinition);
        }

        defined.insert(key.to_string(), false);

        let previous_definition = active_context.terms.remove(key);
        let value = match term {
            JsonValue::Null => {
                let mut obj = Object::new();
                obj.insert("@id", term.clone());
                obj
            }
            JsonValue::String(value) => {
                let mut obj = Object::new();
                obj.insert("@id", JsonValue::String(value.clone()));
                obj
            }
            JsonValue::Object(value) => value.clone(),
            _ => return Err(JsonLdError::InvalidTermDefinition)
        };

        let mut definition = Term {
            prefix: false,
            protected,
            reverse: false,
            ..Term::default()
        };

        let mut has_type = false;

        if let Some(protected) = value.get("@protected") {
            if let JsonValue::Boolean(protected) = protected {
                definition.protected = *protected;
            } else {
                return Err(JsonLdError::InvalidProtectedValue);
            }
        }

        if let Some(term_type) = value.get("@type") {
            has_type = true;
            if let JsonValue::String(term_type) = term_type {
                definition.term_type = Some(Context::iri_expansion(active_context, term_type, defined, None, None, Some(local_context))?);
            } else {
                return Err(JsonLdError::InvalidTypeValue);
            }
        }

        if let Some(reverse) = value.get("@reverse") {
            if let (Some(_), Some(_)) = (value.get("@id"), value.get("@nest")) {
                return Err(JsonLdError::InvalidReverseProperty);
            }

            if let JsonValue::String(reverse) = reverse {
                definition.iri_mapping = Context::iri_expansion(active_context, reverse, defined, None, None, Some(local_context))?;
                definition.reverse = true;
                if let Some(container) = value.get("@container") {
                    if container != "@set" && container != "@index" && container != "null" {
                        return Err(JsonLdError::InvalidReverseProperty);
                    }
                }
                active_context.terms.insert(key.to_string(), definition);
                defined.insert(key.to_string(), true);

                return Ok(());
            } else {
                return Err(JsonLdError::InvalidIRIMapping);
            }
        }

        if let Some(id) = value.get("@id") {
            match id {
                JsonValue::String(id) if id != key => {
                    let iri = Context::iri_expansion(active_context, id, defined, None, None, Some(local_context))?;
                    if !(iri.contains("://") || iri.starts_with("_:") || iri.starts_with('@')) {
                        return Err(JsonLdError::InvalidIRIMapping);
                    }
                    if iri == "@context" {
                        return Err(JsonLdError::InvalidKeywordAlias);
                    }
                    if key.contains(':') && !key.starts_with(':') && key.contains('/') {
                        defined.insert(key.to_string(), true);
                        let term = Context::iri_expansion(active_context, key, defined, None, None, Some(local_context))?;
                        if term != iri {
                            return Err(JsonLdError::InvalidIRIMapping);
                        }
                    } else if iri == "_" || (iri.contains("://") && iri.ends_with([':', '/', '?', '#', '[', ']', '@'])) {
                        definition.prefix = true;
                    }
                    definition.iri_mapping = iri;
                },
                _ => return Err(JsonLdError::InvalidIRIMapping)
            }
        } else if let Some(idx) = key.find(':') {
            let (prefix, suffix) = key.split_at(idx);
            if !suffix.starts_with('/') {
                if let Some(prefix_term) = local_context.get(prefix) {
                    Context::create_term_definition(active_context, local_context, (prefix, prefix_term), defined, 
                                                    base_url, remote_contexts, TermOpts::new(Some(protected),
                                                    Some(override_protected), Some(validate_scoped)))?;
                }
            }
        } else if key.contains('/') {
            let iri = Context::iri_expansion(active_context, key, defined, Some(true), Some(true), Some(local_context))?;
            if !iri.contains("://") {
                return Err(JsonLdError::InvalidIRIMapping);
            }
            definition.iri_mapping = iri;
        } else if key == "@type" {
            definition.iri_mapping = "@type".to_string();
        } else if let Some(vocab) = &active_context.vocab {
            definition.iri_mapping = format!("{}{}", vocab, key);
        } else {
            return Err(JsonLdError::InvalidIRIMapping);
        }

        if let Some(container) = value.get("@container") {
            todo!()
        }

        if let Some(index) = value.get("@index") {
            if let Some(container) = &definition.container {
                if let (JsonValue::String(index), true) = (index, container.contains(&"@index".to_string())) {
                    let iri = Context::iri_expansion(active_context, index, defined, None, None, Some(local_context))?;
                    if !iri.contains("://") {
                        return Err(JsonLdError::InvalidTermDefinition);
                    }
                } else {
                    return Err(JsonLdError::InvalidTermDefinition);
                }
            }
        }

        if let Some(context) = value.get("@context") {
            todo!()//Context::parse_context(active_context, context, base_url, Some(remote_contexts.clone()), Some(true), None, None)?;
        }

        if let (Some(lang), true) = (value.get("@language"), has_type) {
            definition.language = match lang {
                JsonValue::Null => None,
                JsonValue::String(str) => Some(str.to_owned()),
                _ => return Err(JsonLdError::InvalidLanguageMapping)
            }
        }

        if let (Some(direction), true) = (value.get("@direction"), has_type) {
            definition.direction = match direction {
                JsonValue::Null => Some(Direction::NULL),
                JsonValue::String(str) => Some(Direction::from_str(str)?),
                _ => return Err(JsonLdError::InvalidLanguageMapping)
            }
        }

        if let Some(nest) = value.get("@nest") {
            if let JsonValue::String(nest) = nest {
                definition.nest = if nest == "@nest" { Some("@nest".to_owned()) } else { return Err(JsonLdError::InvalidNestValue) };
            } else {
                return Err(JsonLdError::InvalidNestValue);
            }
        }

        if let Some(prefix) = value.get("@prefix") {
            if key.contains(':') || key.contains('/') {
                return Err(JsonLdError::InvalidTermDefinition);
            }

            if let JsonValue::Boolean(prefix) = prefix {
                if *prefix && definition.iri_mapping.starts_with('@') {
                    return Err(JsonLdError::InvalidTermDefinition);
                }
                definition.prefix = *prefix;
            }
        }

        if let (Some(prev), false) = (previous_definition, override_protected) {
            if prev.protected {
                if definition != prev {
                    return Err(JsonLdError::ProtectedTermRedefinition);
                }
                definition = prev;
            }
        }

        active_context.terms.insert(key.to_string(), definition);
        defined.insert(key.to_string(), true)  ;

        Ok(())
    }

    fn iri_expansion(active_context: &mut Context, value: &str, defined: &mut HashMap<String, bool>,
                     document_relative: Option<bool>, vocab: Option<bool>, local_context: Option<&Object>) -> Result<String, JsonLdError> {
        if value.starts_with('@') {
            return Ok(value.to_string());
        }

        let document_relative = document_relative.unwrap_or(false);
        let vocab = vocab.unwrap_or(false);

        if let Some(ctx) = local_context {
            if let Some(JsonValue::String(value)) = ctx.get(value) {
                if let Some(is_defined) = defined.get(value) {
                    if !*is_defined {
                        let term = ctx.get(value).unwrap();
                        Context::create_term_definition(active_context, ctx, (value, term), defined, &String::new(), &Vec::new(), TermOpts::default())?;
                    }
                }
            }
        }

        if let Some(term) = active_context.terms.get(value) {
            if term.iri_mapping.starts_with('@') || vocab {
                return Ok(term.iri_mapping.clone());
            }
        }

        let split_idx = value.find(':').unwrap_or(0);
        if split_idx > 0 {
            let (prefix, suffix) = value.split_at(split_idx);
            let suffix = &suffix[1..];
            if prefix == "_" || suffix.starts_with("//") {
                return Ok(value.to_string());
            }

            if let Some(ctx) = local_context {
                if let Some(JsonValue::String(value)) = ctx.get(prefix) {
                    if let Some(is_defined) = defined.get(value) {
                        if !is_defined {
                            let term = ctx.get(value).unwrap();
                            Context::create_term_definition(active_context, ctx, (value, term), defined, &String::new(), &Vec::new(), TermOpts::default())?;
                        }
                    }
                }
            }

            if let Some(term) = active_context.terms.get(prefix) {
                if term.prefix {
                    // TODO: concatenate this better
                    return Ok(format!("{}{}", term.iri_mapping, suffix));
                }
            }
        }

        if let Some(vocab_map) = &active_context.vocab {
            if vocab {
                return Ok(format!("{}{}", vocab_map, value));
            }
        }

        if document_relative {
            todo!()
        }

        Ok(value.to_string())
    }
}

#[cfg(test)]
mod tests {
    use std::{fs::File, path::Path, io::{Read, self}};

    use json::JsonValue;

    use super::{Context, ContextOpts};

    #[test]
    fn parse_context() -> Result<(), io::Error> {
        let mut json_context = String::new();
        File::open(Path::new("./person.jsonld"))?.read_to_string(&mut json_context)?;

        let context = match json::parse(json_context.as_str()).expect("Failed to parse example context") {
            JsonValue::Object(mut context) => context.remove("@context").unwrap(),
            _ => panic!()
        };

        let context = Context::parse_context(&mut Context::default(), &context, &"https://vlhl.dev".to_owned(), Some(Vec::new()), ContextOpts::new(Some(false), Some(true), Some(false)));

        println!("context: {:#?}", context);

        Ok(())
    }
}