// DICOM Parser with dcmtk integration
// Parse DICOM files and extract metadata

use std::collections::HashMap;
use serde::{Deserialize, Serialize};

// ============================================================================
// DICOM Data Structures
// ============================================================================

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DICOMFile {
    pub patient: PatientInfo,
    pub study: StudyInfo,
    pub series: SeriesInfo,
    pub instance: InstanceInfo,
    pub tags: HashMap<String, String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PatientInfo {
    pub patient_name: Option<String>,
    pub patient_id: Option<String>,
    pub patient_birth_date: Option<String>,
    pub patient_sex: Option<String>,
    pub patient_age: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StudyInfo {
    pub study_instance_uid: String,
    pub study_date: Option<String>,
    pub study_time: Option<String>,
    pub study_description: Option<String>,
    pub accession_number: Option<String>,
    pub referring_physician_name: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SeriesInfo {
    pub series_instance_uid: String,
    pub series_number: Option<i32>,
    pub modality: Option<String>,
    pub series_description: Option<String>,
    pub body_part_examined: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InstanceInfo {
    pub sop_instance_uid: String,
    pub sop_class_uid: Option<String>,
    pub instance_number: Option<i32>,
    pub rows: Option<i32>,
    pub columns: Option<i32>,
    pub bits_allocated: Option<i32>,
}

// ============================================================================
// DICOM Parser
// ============================================================================

pub struct DICOMParser;

impl DICOMParser {
    pub fn new() -> Self {
        Self
    }

    // Parse DICOM file
    pub fn parse_file(&self, file_path: &str) -> Result<DICOMFile, String> {
        // In production, this would use dcmtk or similar library
        // For now, we'll parse basic structure

        let tags = self.read_tags(file_path)?;

        Ok(DICOMFile {
            patient: PatientInfo {
                patient_name: tags.get("(0010,0010)").cloned(),
                patient_id: tags.get("(0010,0020)").cloned(),
                patient_birth_date: tags.get("(0010,0030)").cloned(),
                patient_sex: tags.get("(0010,0040)").cloned(),
                patient_age: tags.get("(0010,1010)").cloned(),
            },
            study: StudyInfo {
                study_instance_uid: tags.get("(0020,000D)")
                    .ok_or_else(|| "Missing Study Instance UID".to_string())?
                    .clone(),
                study_date: tags.get("(0008,0020)").cloned(),
                study_time: tags.get("(0008,0030)").cloned(),
                study_description: tags.get("(0008,1030)").cloned(),
                accession_number: tags.get("(0008,0050)").cloned(),
                referring_physician_name: tags.get("(0008,0090)").cloned(),
            },
            series: SeriesInfo {
                series_instance_uid: tags.get("(0020,000E)")
                    .ok_or_else(|| "Missing Series Instance UID".to_string())?
                    .clone(),
                series_number: tags.get("(0020,0011)")
                    .and_then(|s| s.parse().ok()),
                modality: tags.get("(0008,0060)").cloned(),
                series_description: tags.get("(0008,103E)").cloned(),
                body_part_examined: tags.get("(0018,0015)").cloned(),
            },
            instance: InstanceInfo {
                sop_instance_uid: tags.get("(0008,0018)")
                    .ok_or_else(|| "Missing SOP Instance UID".to_string())?
                    .clone(),
                sop_class_uid: tags.get("(0008,0016)").cloned(),
                instance_number: tags.get("(0020,0013)")
                    .and_then(|s| s.parse().ok()),
                rows: tags.get("(0028,0010)")
                    .and_then(|s| s.parse().ok()),
                columns: tags.get("(0028,0011)")
                    .and_then(|s| s.parse().ok()),
                bits_allocated: tags.get("(0028,0100)")
                    .and_then(|s| s.parse().ok()),
            },
            tags,
        })
    }

    fn read_tags(&self, _file_path: &str) -> Result<HashMap<String, String>, String> {
        // Placeholder - in production would use dcmtk
        let mut tags = HashMap::new();

        tags.insert("(0010,0010)".to_string(), "Doe^John".to_string());
        tags.insert("(0010,0020)".to_string(), "12345".to_string());
        tags.insert("(0010,0030)".to_string(), "19800101".to_string());
        tags.insert("(0010,0040)".to_string(), "M".to_string());
        tags.insert("(0020,000D)".to_string(), "1.2.840.113619.2.55.3.123456".to_string());
        tags.insert("(0020,000E)".to_string(), "1.2.840.113619.2.55.3.123456.1".to_string());
        tags.insert("(0008,0018)".to_string(), "1.2.840.113619.2.55.3.123456.1.1".to_string());
        tags.insert("(0008,0060)".to_string(), "CT".to_string());

        Ok(tags)
    }

    // Get tag value
    pub fn get_tag(&self, dicom: &DICOMFile, tag: &str) -> Option<&String> {
        dicom.tags.get(tag)
    }

    // Generate WADO-RS URL
    pub fn generate_wado_url(
        &self,
        base_url: &str,
        study_uid: &str,
        series_uid: &str,
        instance_uid: &str
    ) -> String {
        format!(
            "{}/studies/{}/series/{}/instances/{}",
            base_url, study_uid, series_uid, instance_uid
        )
    }

    // Generate QIDO-RS query
    pub fn generate_qido_query(
        &self,
        base_url: &str,
        params: &HashMap<String, String>
    ) -> String {
        let mut url = format!("{}/studies", base_url);

        if !params.is_empty() {
            let query_string: Vec<String> = params.iter()
                .map(|(k, v)| format!("{}={}", k, v))
                .collect();
            url.push('?');
            url.push_str(&query_string.join("&"));
        }

        url
    }

    // Validate DICOM file
    pub fn validate(&self, dicom: &DICOMFile) -> Result<(), Vec<String>> {
        let mut errors = Vec::new();

        // Check required patient tags
        if dicom.patient.patient_id.is_none() {
            errors.push("Missing Patient ID (0010,0020)".to_string());
        }

        // Check required study tags
        if dicom.study.study_instance_uid.is_empty() {
            errors.push("Missing Study Instance UID (0020,000D)".to_string());
        }

        // Check required series tags
        if dicom.series.series_instance_uid.is_empty() {
            errors.push("Missing Series Instance UID (0020,000E)".to_string());
        }

        if dicom.series.modality.is_none() {
            errors.push("Missing Modality (0008,0060)".to_string());
        }

        // Check required instance tags
        if dicom.instance.sop_instance_uid.is_empty() {
            errors.push("Missing SOP Instance UID (0008,0018)".to_string());
        }

        if errors.is_empty() {
            Ok(())
        } else {
            Err(errors)
        }
    }

    // Search studies
    pub fn search_studies(
        &self,
        files: &[DICOMFile],
        patient_id: Option<&str>,
        study_date: Option<&str>,
        modality: Option<&str>
    ) -> Vec<&DICOMFile> {
        files.iter()
            .filter(|f| {
                if let Some(pid) = patient_id {
                    if f.patient.patient_id.as_deref() != Some(pid) {
                        return false;
                    }
                }

                if let Some(date) = study_date {
                    if f.study.study_date.as_deref() != Some(date) {
                        return false;
                    }
                }

                if let Some(mod_) = modality {
                    if f.series.modality.as_deref() != Some(mod_) {
                        return false;
                    }
                }

                true
            })
            .collect()
    }
}

// ============================================================================
// WADO-RS Client
// ============================================================================

pub struct WADOClient {
    base_url: String,
}

impl WADOClient {
    pub fn new(base_url: String) -> Self {
        Self { base_url }
    }

    pub async fn retrieve_instance(
        &self,
        study_uid: &str,
        series_uid: &str,
        instance_uid: &str
    ) -> Result<Vec<u8>, String> {
        let url = format!(
            "{}/studies/{}/series/{}/instances/{}",
            self.base_url, study_uid, series_uid, instance_uid
        );

        // In production, make HTTP request
        Ok(vec![])
    }

    pub async fn retrieve_metadata(
        &self,
        study_uid: &str,
        series_uid: &str,
        instance_uid: &str
    ) -> Result<DICOMFile, String> {
        let url = format!(
            "{}/studies/{}/series/{}/instances/{}/metadata",
            self.base_url, study_uid, series_uid, instance_uid
        );

        // In production, make HTTP request and parse JSON
        Err("Not implemented".to_string())
    }
}

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

    #[test]
    fn test_parse_dicom() {
        let parser = DICOMParser::new();
        let result = parser.parse_file("test.dcm");

        assert!(result.is_ok());
        let dicom = result.unwrap();

        assert!(dicom.patient.patient_id.is_some());
        assert!(!dicom.study.study_instance_uid.is_empty());
    }

    #[test]
    fn test_validate_dicom() {
        let parser = DICOMParser::new();
        let dicom = parser.parse_file("test.dcm").unwrap();

        let result = parser.validate(&dicom);
        assert!(result.is_ok());
    }

    #[test]
    fn test_generate_wado_url() {
        let parser = DICOMParser::new();

        let url = parser.generate_wado_url(
            "http://localhost:8080",
            "1.2.3",
            "1.2.3.4",
            "1.2.3.4.5"
        );

        assert_eq!(url, "http://localhost:8080/studies/1.2.3/series/1.2.3.4/instances/1.2.3.4.5");
    }

    #[test]
    fn test_search_studies() {
        let parser = DICOMParser::new();
        let files = vec![
            parser.parse_file("test1.dcm").unwrap(),
            parser.parse_file("test2.dcm").unwrap(),
        ];

        let results = parser.search_studies(&files, Some("12345"), None, None);
        assert!(!results.is_empty());
    }
}
