// Copyright (c) 2025-2026 Probo Inc <hello@getprobo.com>.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

package docgen

import (
	"bytes"
	_ "embed"
	"encoding/json"
	"fmt"
	"html"
	"html/template"
	"strings"
	"time"

	"go.probo.inc/probo/pkg/coredata"
	"go.probo.inc/probo/pkg/prosemirror"
)

var (
	//go:embed mermaid.min.js
	mermaidJSSource string

	//go:embed template.html
	htmlTemplateContent string

	//go:embed processing_activities_template.html
	processingActivitiesTemplateContent string

	//go:embed data_protection_impact_assessments_template.html
	dataProtectionImpactAssessmentsTemplateContent string

	//go:embed transfer_impact_assessments_template.html
	transferImpactAssessmentsTemplateContent string

	templateFuncs = template.FuncMap{
		"now":                  func() time.Time { return time.Now() },
		"eq":                   func(a, b any) bool { return a == b },
		"add":                  func(a, b int) int { return a + b },
		"string":               func(v fmt.Stringer) string { return v.String() },
		"lower":                func(s string) string { return strings.ToLower(s) },
		"classificationString": func(c Classification) string { return string(c) },
		"boolToYesNo": func(b *bool) string {
			if b == nil {
				return ""
			}
			if *b {
				return "yes"
			}
			return "no"
		},
		"derefString": func(s *string) string {
			if s == nil {
				return ""
			}
			return *s
		},
		"boolToYesNoDash": func(b *bool) string {
			if b == nil {
				return "-"
			}
			if *b {
				return "Yes"
			}
			return "No"
		},
		"imgTag": func(src, alt, class string) template.HTML {
			return template.HTML(fmt.Sprintf(`<img src="%s" alt="%s" class="%s">`, html.EscapeString(src), html.EscapeString(alt), html.EscapeString(class)))
		},
		"formatLawfulBasis": func(basis coredata.ProcessingActivityLawfulBasis) string {
			switch basis {
			case coredata.ProcessingActivityLawfulBasisConsent:
				return "Consent"
			case coredata.ProcessingActivityLawfulBasisContractualNecessity:
				return "Contractual Necessity"
			case coredata.ProcessingActivityLawfulBasisLegalObligation:
				return "Legal Obligation"
			case coredata.ProcessingActivityLawfulBasisLegitimateInterest:
				return "Legitimate Interest"
			case coredata.ProcessingActivityLawfulBasisPublicTask:
				return "Public Task"
			case coredata.ProcessingActivityLawfulBasisVitalInterests:
				return "Vital Interests"
			default:
				return basis.String()
			}
		},
		"formatSpecialOrCriminalData": func(data coredata.ProcessingActivitySpecialOrCriminalDatum) string {
			switch data {
			case coredata.ProcessingActivitySpecialOrCriminalDatumYes:
				return "Yes"
			case coredata.ProcessingActivitySpecialOrCriminalDatumNo:
				return "No"
			case coredata.ProcessingActivitySpecialOrCriminalDatumPossible:
				return "Possible"
			default:
				return data.String()
			}
		},
		"formatTransferSafeguard": func(safeguard *coredata.ProcessingActivityTransferSafeguard) string {
			if safeguard == nil {
				return ""
			}
			switch *safeguard {
			case coredata.ProcessingActivityTransferSafeguardStandardContractualClauses:
				return "Standard Contractual Clauses"
			case coredata.ProcessingActivityTransferSafeguardBindingCorporateRules:
				return "Binding Corporate Rules"
			case coredata.ProcessingActivityTransferSafeguardAdequacyDecision:
				return "Adequacy Decision"
			case coredata.ProcessingActivityTransferSafeguardDerogations:
				return "Derogations"
			case coredata.ProcessingActivityTransferSafeguardCodesOfConduct:
				return "Codes of Conduct"
			case coredata.ProcessingActivityTransferSafeguardCertificationMechanisms:
				return "Certification Mechanisms"
			default:
				return safeguard.String()
			}
		},
		"formatDPIANeeded": func(needed coredata.ProcessingActivityDataProtectionImpactAssessment) string {
			switch needed {
			case coredata.ProcessingActivityDataProtectionImpactAssessmentNeeded:
				return "Yes"
			case coredata.ProcessingActivityDataProtectionImpactAssessmentNotNeeded:
				return "No"
			default:
				return needed.String()
			}
		},
		"formatTIANeeded": func(needed coredata.ProcessingActivityTransferImpactAssessment) string {
			switch needed {
			case coredata.ProcessingActivityTransferImpactAssessmentNeeded:
				return "Yes"
			case coredata.ProcessingActivityTransferImpactAssessmentNotNeeded:
				return "No"
			default:
				return needed.String()
			}
		},
		"formatRole": func(role coredata.ProcessingActivityRole) string {
			switch role {
			case coredata.ProcessingActivityRoleController:
				return "Controller"
			case coredata.ProcessingActivityRoleProcessor:
				return "Processor"
			default:
				return role.String()
			}
		},
		"formatResidualRisk": func(risk *coredata.DataProtectionImpactAssessmentResidualRisk) string {
			if risk == nil {
				return ""
			}
			switch *risk {
			case coredata.DataProtectionImpactAssessmentResidualRiskLow:
				return "Low"
			case coredata.DataProtectionImpactAssessmentResidualRiskMedium:
				return "Medium"
			case coredata.DataProtectionImpactAssessmentResidualRiskHigh:
				return "High"
			default:
				return risk.String()
			}
		},
	}

	documentTemplate = template.Must(template.New("document").Funcs(templateFuncs).Parse(htmlTemplateContent))

	processingActivitiesTemplate = template.Must(template.New("processingActivities").Funcs(templateFuncs).Parse(processingActivitiesTemplateContent))

	dataProtectionImpactAssessmentsTemplate = template.Must(template.New("dataProtectionImpactAssessments").Funcs(templateFuncs).Parse(dataProtectionImpactAssessmentsTemplateContent))

	transferImpactAssessmentsTemplate = template.Must(template.New("transferImpactAssessments").Funcs(templateFuncs).Parse(transferImpactAssessmentsTemplateContent))
)

type (
	Classification string

	DocumentData struct {
		Title                       string
		Content                     json.RawMessage // ProseMirror/Tiptap document JSON; use ProseMirrorJSONToHTML for HTML
		Major                       int
		Minor                       int
		Classification              Classification
		Approvers                   []string
		Description                 string
		PublishedAt                 *time.Time
		Signatures                  []SignatureData
		CompanyHorizontalLogoBase64 string
		MermaidJS                   template.JS
		Landscape                   bool
	}

	SignatureData struct {
		SignedBy    string
		SignedAt    *time.Time
		State       coredata.DocumentVersionSignatureState
		RequestedAt time.Time
	}

	ProcessingActivityTableData struct {
		CompanyName                 string
		CompanyHorizontalLogoBase64 string
		Version                     int
		PublishedAt                 time.Time
		Activities                  []ProcessingActivityRowData
	}

	ProcessingActivityRowData struct {
		Name                                 string
		Purpose                              *string
		DataSubjectCategory                  *string
		PersonalDataCategory                 *string
		SpecialOrCriminalData                coredata.ProcessingActivitySpecialOrCriminalDatum
		ConsentEvidenceLink                  *string
		LawfulBasis                          coredata.ProcessingActivityLawfulBasis
		Recipients                           *string
		Location                             *string
		InternationalTransfers               bool
		TransferSafeguards                   *coredata.ProcessingActivityTransferSafeguard
		RetentionPeriod                      *string
		SecurityMeasures                     *string
		DataProtectionImpactAssessmentNeeded coredata.ProcessingActivityDataProtectionImpactAssessment
		TransferImpactAssessmentNeeded       coredata.ProcessingActivityTransferImpactAssessment
		LastReviewDate                       *time.Time
		NextReviewDate                       *time.Time
		Role                                 coredata.ProcessingActivityRole
		DataProtectionOfficerFullName        *string
		Vendors                              string
	}

	DataProtectionImpactAssessmentTableData struct {
		CompanyName                 string
		CompanyHorizontalLogoBase64 string
		Version                     int
		PublishedAt                 time.Time
		Assessments                 []DataProtectionImpactAssessmentRowData
	}

	DataProtectionImpactAssessmentRowData struct {
		ProcessingActivityName      string
		Description                 *string
		NecessityAndProportionality *string
		PotentialRisk               *string
		Mitigations                 *string
		ResidualRisk                *coredata.DataProtectionImpactAssessmentResidualRisk
	}

	TransferImpactAssessmentTableData struct {
		CompanyName                 string
		CompanyHorizontalLogoBase64 string
		Version                     int
		PublishedAt                 time.Time
		Assessments                 []TransferImpactAssessmentRowData
	}

	TransferImpactAssessmentRowData struct {
		ProcessingActivityName string
		DataSubjects           *string
		LegalMechanism         *string
		Transfer               *string
		LocalLawRisk           *string
		SupplementaryMeasures  *string
	}

	StatementOfApplicabilityData struct {
		Title            string
		OrganizationName string
		CreatedAt        time.Time
		TotalControls    int
		Rows             []SOARow
	}

	SOARow struct {
		FrameworkName        string
		ControlSection       string
		ControlName          string
		Applicability        string
		Justification        string
		MaturityLevel        string
		NotImplJustification string
		Regulatory           string
		Contractual          string
		BestPractice         string
		RiskAssessment       string
	}

	DataListData struct {
		Title            string
		OrganizationName string
		CreatedAt        time.Time
		TotalData        int
		Rows             []DataListRow
	}

	DataListRow struct {
		Name           string
		Classification string
		Owner          string
		Vendors        string
	}

	AssetListData struct {
		Title            string
		OrganizationName string
		CreatedAt        time.Time
		TotalAssets      int
		Rows             []AssetListRow
	}

	AssetListRow struct {
		Name            string
		AssetType       string
		Amount          int
		DataTypesStored string
		Owner           string
		Vendors         string
	}
)

func BoolLabel(v bool) string {
	if v {
		return "Yes"
	}
	return "No"
}

func MaturityLabel(l coredata.ControlMaturityLevel) string {
	switch l {
	case coredata.ControlMaturityLevelNone:
		return "0 - None"
	case coredata.ControlMaturityLevelInitial:
		return "1 - Initial"
	case coredata.ControlMaturityLevelManaged:
		return "2 - Managed"
	case coredata.ControlMaturityLevelDefined:
		return "3 - Defined"
	case coredata.ControlMaturityLevelQuantitativelyManaged:
		return "4 - Quantitatively Managed"
	case coredata.ControlMaturityLevelOptimizing:
		return "5 - Optimizing"
	}
	return "Not set"
}

const (
	ClassificationPublic       Classification = "PUBLIC"
	ClassificationInternal     Classification = "INTERNAL"
	ClassificationConfidential Classification = "CONFIDENTIAL"
	ClassificationSecret       Classification = "SECRET"
)

// ProseMirrorJSONToHTML converts ProseMirror/Tiptap document JSON to an HTML fragment.
// On parse or render failure it returns a single escaped paragraph with the raw input.
func ProseMirrorJSONToHTML(content json.RawMessage) template.HTML {
	s := strings.TrimSpace(string(content))
	if s == "" {
		return template.HTML("")
	}
	node, err := prosemirror.Parse(s)
	if err != nil {
		return template.HTML(fmt.Sprintf("<p>%s</p>", html.EscapeString(s)))
	}
	htmlStr, err := prosemirror.RenderHTML(node)
	if err != nil {
		return template.HTML(fmt.Sprintf("<p>%s</p>", html.EscapeString(s)))
	}
	return template.HTML(htmlStr)
}

func RenderHTML(data DocumentData) ([]byte, error) {
	data.MermaidJS = template.JS(mermaidJSSource)

	page := struct {
		DocumentData
		BodyHTML template.HTML
	}{
		DocumentData: data,
		BodyHTML:     ProseMirrorJSONToHTML(data.Content),
	}

	var buf bytes.Buffer
	if err := documentTemplate.Execute(&buf, page); err != nil {
		return nil, fmt.Errorf("cannot execute template: %w", err)
	}

	return buf.Bytes(), nil
}

func RenderProcessingActivitiesTableHTML(data ProcessingActivityTableData) ([]byte, error) {
	var buf bytes.Buffer
	if err := processingActivitiesTemplate.Execute(&buf, data); err != nil {
		return nil, fmt.Errorf("cannot execute processing activities template: %w", err)
	}

	return buf.Bytes(), nil
}

func RenderDataProtectionImpactAssessmentsTableHTML(data DataProtectionImpactAssessmentTableData) ([]byte, error) {
	var buf bytes.Buffer
	if err := dataProtectionImpactAssessmentsTemplate.Execute(&buf, data); err != nil {
		return nil, fmt.Errorf("cannot execute data protection impact assessments template: %w", err)
	}

	return buf.Bytes(), nil
}

func RenderTransferImpactAssessmentsTableHTML(data TransferImpactAssessmentTableData) ([]byte, error) {
	var buf bytes.Buffer
	if err := transferImpactAssessmentsTemplate.Execute(&buf, data); err != nil {
		return nil, fmt.Errorf("cannot execute transfer impact assessments template: %w", err)
	}

	return buf.Bytes(), nil
}