//! Medical report generation.
//!
//! Generates structured medical reports from multi-modal analysis.

use tumorboard_shared::{
    CTFindings, CaseAnalysisRequest, FusedAnalysis, MRIFindings, MedicalReport, PathologyFindings,
    Recommendation, ReportMetadata, ReportSection,
};

/// Error type for report generation.
#[derive(Debug, thiserror::Error)]
pub enum ReportError {
    /// Missing required data.
    #[error("Missing required data: {0}")]
    MissingData(String),

    /// Template error.
    #[error("Report template error: {0}")]
    TemplateError(String),
}

/// Report generator.
#[derive(Debug)]
pub struct ReportGenerator {
    /// Include detailed methodology.
    include_methodology: bool,
    /// Model version.
    model_version: String,
}

impl Default for ReportGenerator {
    fn default() -> Self {
        Self::new()
    }
}

impl ReportGenerator {
    /// Create a new report generator.
    #[must_use]
    pub fn new() -> Self {
        Self {
            include_methodology: true,
            model_version: "TumorBoard-AI-v1.0".to_string(),
        }
    }

    /// Generate a medical report.
    ///
    /// # Errors
    ///
    /// Returns error if required data is missing.
    pub fn generate(
        &self,
        request: &CaseAnalysisRequest,
        ct_findings: &Option<CTFindings>,
        mri_findings: &Option<MRIFindings>,
        pathology_findings: &Option<PathologyFindings>,
        fused: &FusedAnalysis,
        recommendations: &[Recommendation],
    ) -> Result<MedicalReport, ReportError> {
        let mut sections = Vec::new();

        // Clinical history section
        sections.push(self.build_clinical_section(request));

        // Imaging findings section
        if ct_findings.is_some() || mri_findings.is_some() {
            sections.push(self.build_imaging_section(ct_findings, mri_findings));
        }

        // Pathology section
        if let Some(path) = pathology_findings {
            sections.push(self.build_pathology_section(path));
        }

        // Integrated findings section
        sections.push(self.build_integrated_section(fused));

        // Recommendations section
        if !recommendations.is_empty() {
            sections.push(self.build_recommendations_section(recommendations));
        }

        // Methodology section
        if self.include_methodology {
            sections.push(self.build_methodology_section());
        }

        // Generate summary
        let summary = self.build_summary(fused);

        // Generate impression
        let impression = self.build_impression(fused);

        Ok(MedicalReport {
            sections,
            summary,
            impression,
            metadata: ReportMetadata {
                generated_at: chrono_lite_timestamp(),
                model_version: self.model_version.clone(),
                disclaimer: self.generate_disclaimer(),
            },
        })
    }

    /// Build clinical history section.
    fn build_clinical_section(&self, request: &CaseAnalysisRequest) -> ReportSection {
        let mut content = String::new();

        content.push_str("CLINICAL HISTORY:\n\n");

        if let Some(age) = request.patient_info.age {
            content.push_str(&format!("Age: {age} years\n"));
        }

        if let Some(sex) = &request.patient_info.sex {
            content.push_str(&format!("Sex: {sex:?}\n"));
        }

        if !request.patient_info.medical_history.is_empty() {
            content.push_str("\nRelevant History:\n");
            for item in &request.patient_info.medical_history {
                content.push_str(&format!("  - {item}\n"));
            }
        }

        content.push_str(&format!(
            "\nClinical Question: {}\n",
            request.clinical_context.clinical_question
        ));

        if !request.clinical_context.lab_values.is_empty() {
            content.push_str("\nRelevant Lab Values:\n");
            for lab in &request.clinical_context.lab_values {
                content.push_str(&format!("  - {}: {} {}\n", lab.name, lab.value, lab.unit));
            }
        }

        ReportSection {
            title: "Clinical History".to_string(),
            content,
            image_references: vec![],
        }
    }

    /// Build imaging findings section.
    fn build_imaging_section(
        &self,
        ct: &Option<CTFindings>,
        mri: &Option<MRIFindings>,
    ) -> ReportSection {
        let mut content = String::new();

        content.push_str("IMAGING FINDINGS:\n\n");

        if let Some(ct_findings) = ct {
            content.push_str("CT Findings:\n");
            content.push_str(&format!("  {}\n", ct_findings.assessment));

            if !ct_findings.lesions.is_empty() {
                content.push_str("\n  Lesions:\n");
                for lesion in &ct_findings.lesions {
                    content.push_str(&format!(
                        "    - {}: {:.1} x {:.1} x {:.1} mm, {:?}\n",
                        lesion.location.region,
                        lesion.size[0],
                        lesion.size[1],
                        lesion.size[2],
                        lesion.lesion_type
                    ));
                }
            }

            content.push_str(&format!(
                "\n  Confidence: {:.0}%\n",
                ct_findings.confidence * 100.0
            ));
        }

        if let Some(mri_findings) = mri {
            if ct.is_some() {
                content.push('\n');
            }
            content.push_str("MRI Findings:\n");
            content.push_str(&format!("  {}\n", mri_findings.assessment));

            if !mri_findings.sequence_findings.is_empty() {
                content.push_str("\n  Sequence Findings:\n");
                for seq in &mri_findings.sequence_findings {
                    content.push_str(&format!("    - {}: {}\n", seq.sequence, seq.finding));
                }
            }

            if let Some(enh) = &mri_findings.enhancement_pattern {
                content.push_str(&format!(
                    "\n  Enhancement: {} ({:?})\n",
                    enh.pattern, enh.degree
                ));
            }

            content.push_str(&format!(
                "\n  Confidence: {:.0}%\n",
                mri_findings.confidence * 100.0
            ));
        }

        ReportSection {
            title: "Imaging Findings".to_string(),
            content,
            image_references: vec![],
        }
    }

    /// Build pathology section.
    fn build_pathology_section(&self, path: &PathologyFindings) -> ReportSection {
        let mut content = String::new();

        content.push_str("PATHOLOGY FINDINGS:\n\n");
        content.push_str(&format!("Diagnosis: {}\n", path.assessment));

        if let Some(grade) = &path.grading {
            content.push_str(&format!("\nGrade: {} ({})\n", grade.grade, grade.system));
        }

        if !path.biomarkers.is_empty() {
            content.push_str("\nBiomarkers:\n");
            for marker in &path.biomarkers {
                let expr = marker
                    .expression
                    .map(|e| format!(" ({e:.0}%)"))
                    .unwrap_or_default();
                content.push_str(&format!(
                    "  - {}: {:?}{}\n",
                    marker.name, marker.status, expr
                ));
            }
        }

        content.push_str(&format!("\nConfidence: {:.0}%\n", path.confidence * 100.0));

        ReportSection {
            title: "Pathology Findings".to_string(),
            content,
            image_references: vec![],
        }
    }

    /// Build integrated findings section.
    fn build_integrated_section(&self, fused: &FusedAnalysis) -> ReportSection {
        let mut content = String::new();

        content.push_str("INTEGRATED ANALYSIS:\n\n");

        content.push_str(&format!(
            "Primary Diagnosis: {} (probability: {:.0}%)\n",
            fused.primary_diagnosis.name,
            fused.primary_diagnosis.probability * 100.0
        ));

        if let Some(icd) = &fused.primary_diagnosis.icd_code {
            content.push_str(&format!("ICD-10: {icd}\n"));
        }

        if !fused.differential_diagnoses.is_empty() {
            content.push_str("\nDifferential Diagnoses:\n");
            for dx in &fused.differential_diagnoses {
                content.push_str(&format!(
                    "  - {} ({:.0}%)\n",
                    dx.name,
                    dx.probability * 100.0
                ));
            }
        }

        if let Some(assessment) = &fused.tumor_assessment {
            if let Some(tnm) = &assessment.tnm_stage {
                content.push_str(&format!(
                    "\nTNM Staging: T{} N{} M{} (Stage {})\n",
                    tnm.t, tnm.n, tnm.m, tnm.overall_stage
                ));
            }

            if !assessment.prognostic_factors.is_empty() {
                content.push_str("\nPrognostic Factors:\n");
                for factor in &assessment.prognostic_factors {
                    content.push_str(&format!(
                        "  - {}: {} ({:?})\n",
                        factor.name, factor.value, factor.impact
                    ));
                }
            }
        }

        if !fused.correlations.is_empty() {
            content.push_str("\nCross-Modal Correlations:\n");
            for corr in &fused.correlations {
                content.push_str(&format!(
                    "  - {:?} ↔ {:?}: {} ({:?})\n",
                    corr.modality_a, corr.modality_b, corr.description, corr.correlation_type
                ));
            }
        }

        content.push_str(&format!(
            "\nOverall Confidence: {:.0}%\n",
            fused.confidence * 100.0
        ));

        ReportSection {
            title: "Integrated Analysis".to_string(),
            content,
            image_references: vec![],
        }
    }

    /// Build recommendations section.
    fn build_recommendations_section(&self, recommendations: &[Recommendation]) -> ReportSection {
        let mut content = String::new();

        content.push_str("RECOMMENDATIONS:\n\n");

        for (i, rec) in recommendations.iter().enumerate() {
            content.push_str(&format!(
                "{}. [{:?}] {:?}: {}\n",
                i + 1,
                rec.priority,
                rec.recommendation_type,
                rec.description
            ));
            content.push_str(&format!("   Rationale: {}\n\n", rec.rationale));
        }

        ReportSection {
            title: "Recommendations".to_string(),
            content,
            image_references: vec![],
        }
    }

    /// Build methodology section.
    fn build_methodology_section(&self) -> ReportSection {
        let content = r"METHODOLOGY:

This analysis was performed using the TumorBoard AI system, which employs
deep learning models for multi-modal medical image analysis.

CT Analysis:
  - 3D convolutional neural network for lesion detection
  - Volumetric measurement using automated segmentation
  - Malignancy probability estimation based on imaging features

MRI Analysis:
  - Multi-sequence feature extraction
  - Enhancement pattern characterization
  - Diffusion analysis when available

Pathology Analysis:
  - Whole slide image analysis
  - Cell detection and classification
  - Biomarker quantification using validated algorithms

Multi-Modal Fusion:
  - Cross-attention mechanism for modality integration
  - Concordance assessment between modalities
  - Integrated staging using AJCC guidelines
"
        .to_string();

        ReportSection {
            title: "Methodology".to_string(),
            content,
            image_references: vec![],
        }
    }

    /// Build summary.
    fn build_summary(&self, fused: &FusedAnalysis) -> String {
        format!(
            "{} with {:.0}% probability. {}",
            fused.primary_diagnosis.name,
            fused.primary_diagnosis.probability * 100.0,
            fused
                .tumor_assessment
                .as_ref()
                .and_then(|a| a.tnm_stage.as_ref())
                .map(|s| format!("Stage {}.", s.overall_stage))
                .unwrap_or_default()
        )
    }

    /// Build impression.
    fn build_impression(&self, fused: &FusedAnalysis) -> String {
        let mut impression = String::new();

        impression.push_str(&format!(
            "1. {}: {:.0}% probability\n",
            fused.primary_diagnosis.name,
            fused.primary_diagnosis.probability * 100.0
        ));

        if let Some(assessment) = &fused.tumor_assessment
            && let Some(tnm) = &assessment.tnm_stage
        {
            impression.push_str(&format!(
                "2. Clinical stage: {} (T{}N{}M{})\n",
                tnm.overall_stage, tnm.t, tnm.n, tnm.m
            ));
        }

        impression.push_str(&format!(
            "3. Overall analysis confidence: {:.0}%\n",
            fused.confidence * 100.0
        ));

        impression
    }

    /// Generate disclaimer.
    fn generate_disclaimer(&self) -> String {
        "DISCLAIMER: This AI-generated report is intended to assist healthcare providers \
         and should not replace clinical judgment. All findings should be correlated with \
         clinical history and verified by qualified medical professionals before treatment \
         decisions are made. This system is not FDA-approved for clinical use."
            .to_string()
    }
}

/// Generate a simple timestamp.
fn chrono_lite_timestamp() -> String {
    use std::time::{SystemTime, UNIX_EPOCH};

    let duration = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .unwrap_or_default();

    format!("{}000", duration.as_secs())
}

#[cfg(test)]
mod tests {
    use super::*;
    use tumorboard_shared::{
        AnalysisConfig, ClinicalContext, Diagnosis, ImagingModality, LabValue, PatientInfo, Sex,
    };

    fn create_test_request() -> CaseAnalysisRequest {
        CaseAnalysisRequest {
            case_id: "TEST001".to_string(),
            patient_info: PatientInfo {
                age: Some(65),
                sex: Some(Sex::Male),
                medical_history: vec!["Former smoker".to_string()],
            },
            studies: vec![],
            clinical_context: ClinicalContext {
                clinical_question: "Evaluate lung nodule".to_string(),
                known_diagnosis: None,
                lab_values: vec![LabValue {
                    name: "CEA".to_string(),
                    value: 8.5,
                    unit: "ng/mL".to_string(),
                    reference_range: Some((0.0, 3.0)),
                }],
                prior_treatments: vec![],
            },
            config: AnalysisConfig::default(),
        }
    }

    fn create_fused_analysis() -> FusedAnalysis {
        FusedAnalysis {
            primary_diagnosis: Diagnosis {
                icd_code: Some("C34.9".to_string()),
                name: "Lung adenocarcinoma".to_string(),
                probability: 0.85,
                evidence: vec![],
            },
            differential_diagnoses: vec![],
            correlations: vec![],
            tumor_assessment: None,
            confidence: 0.88,
        }
    }

    #[test]
    fn test_report_generator_creation() {
        let generator = ReportGenerator::new();
        assert!(generator.include_methodology);
    }

    #[test]
    fn test_generate_report() {
        let generator = ReportGenerator::new();
        let request = create_test_request();
        let fused = create_fused_analysis();

        let result = generator.generate(&request, &None, &None, &None, &fused, &[]);

        assert!(result.is_ok());
        let report = result.unwrap();
        assert!(!report.sections.is_empty());
        assert!(!report.summary.is_empty());
    }

    #[test]
    fn test_clinical_section() {
        let generator = ReportGenerator::new();
        let request = create_test_request();

        let section = generator.build_clinical_section(&request);
        assert!(section.content.contains("Age: 65"));
        assert!(section.content.contains("Former smoker"));
    }

    #[test]
    fn test_summary_generation() {
        let generator = ReportGenerator::new();
        let fused = create_fused_analysis();

        let summary = generator.build_summary(&fused);
        assert!(summary.contains("Lung adenocarcinoma"));
        assert!(summary.contains("85%"));
    }

    #[test]
    fn test_impression_generation() {
        let generator = ReportGenerator::new();
        let fused = create_fused_analysis();

        let impression = generator.build_impression(&fused);
        assert!(impression.contains("Lung adenocarcinoma"));
    }

    #[test]
    fn test_disclaimer() {
        let generator = ReportGenerator::new();
        let disclaimer = generator.generate_disclaimer();

        assert!(disclaimer.contains("DISCLAIMER"));
        assert!(disclaimer.contains("clinical judgment"));
    }

    #[test]
    fn test_methodology_section() {
        let generator = ReportGenerator::new();
        let section = generator.build_methodology_section();

        assert!(section.content.contains("METHODOLOGY"));
        assert!(section.content.contains("deep learning"));
    }
}